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Infraspinatus Muscle Atrophy in Professional Baseball Players
Abstract
Infraspinatus muscle atrophy has been observed in athletes who stress their upper extremities in an overhead fashion. The majority of such case reports have been in volleyball players, with far fewer cases reported in baseball players.
Infraspinatus muscle atrophy occurs to a notable degree in professional baseball players.
Retrospective cohort study.
At the end of the 1999 baseball season, data were collected from all Major League Baseball teams in regards to players affected with infraspinatus muscle atrophy.
Twelve of the 1491 major league professional baseball players were identified as having appreciable infraspinatus muscle atrophy. There was an increased prevalence of the muscle atrophy in professional pitchers (10 of 494, 4%) compared to position players (2 of 997, 0.2%) (P <0.001). Among affected pitchers, the atrophy was identified more frequently in starting pitchers (8 of 10) compared to relief pitchers (2 of 10) (P = 0.036), pitchers who had played for more years at the major league level (8.7 +/- 4.9 versus 5.2 +/- 4.0) (P = 0.017), and pitchers who had thrown for more innings at the major league level (971.4 +/- 784.4 versus 485.0 +/- 594.6) (P <0.001).
Infraspinatus atrophy was identified in 4.4% of major league starting pitchers and occurred in those pitchers who pitched for more years and innings during their major league career.
... Isolated infraspinatus muscle atrophy is common in overhead athletes, who place significant and repetitive stresses across their dominant shoulders. Studies on volleyball and baseball players report infraspinatus atrophy in 4% to 34% of players [7][8][9][10][11]17,22,27 ; however, the prevalence of infraspinatus atrophy in professional tennis players has not been reported. The muscle wasting is thought to be secondary to irritation of the suprascapular nerve at the spinoglenoid notch, distal to its innervation of the supraspinatus muscle. ...
... Isolated atrophy and weakness of the infraspinatus muscle occur 14,27 ; however, the clinical relevance is unclear, with most patients reporting no pain and apparently normal shoulder function. 7 Infraspinatus atrophy has been associated with a higher level and duration of play, leading to the term cumulative neuropraxia 7 as a suggested origin. ...
... We found no association of infraspinatus atrophy with shoulder pain or with other shoulder disorders, and no player had undergone previous shoulder surgery for any reason. Similar to previous studies, 7,9,11,13,14 players with infraspinatus atrophy did not report compromised sporting performance because of external rotation weakness. Presumably, teres minor and the posterior deltoid muscle can compensate for loss of infraspinatus function; however, more subtle functional deficits may still be present. ...
Isolated infraspinatus muscle atrophy is common in overhead athletes, who place significant and repetitive stresses across their dominant shoulders. Studies on volleyball and baseball players report infraspinatus atrophy in 4% to 34% of players; however, the prevalence of infraspinatus atrophy in professional tennis players has not been reported.
To investigate the incidence of isolated infraspinatus atrophy in professional tennis players and to identify any correlations with other physical examination findings, ranking performance, and concurrent shoulder injuries.
Cross-sectional study; Level of evidence, 3.
A total of 125 professional female tennis players underwent a comprehensive preparticipation physical health status examination. Two orthopaedic surgeons examined the shoulders of all players and obtained digital goniometric measurements of range of motion (ROM). Infraspinatus atrophy was defined as loss of soft tissue bulk in the infraspinatus scapula fossa (and increased prominence of dorsal scapular bony anatomy) of the dominant shoulder with clear asymmetry when compared with the contralateral side. Correlations were examined between infraspinatus atrophy and concurrent shoulder disorders, clinical examination findings, ROM, glenohumeral internal rotation deficit, singles tennis ranking, and age.
There were 65 players (52%) with evidence of infraspinatus atrophy in their dominant shoulders. No wasting was noted in the nondominant shoulder of any player. No statistically significant differences were seen in mean age, left- or right-hand dominance, height, weight, or body mass index for players with or without atrophy. Of the 77 players ranked in the top 100, 58% had clinical infraspinatus atrophy, compared with 40% of players ranked outside the top 100. No associations were found with static physical examination findings (scapular dyskinesis, ROM glenohumeral internal rotation deficit, postural abnormalities), concurrent shoulder disorders, or compromised performance when measured by singles ranking.
This study reports a high level of clinical infraspinatus atrophy in the dominant shoulder of elite female tennis players. Infraspinatus atrophy was associated with a higher performance ranking, and no functional deficits or associations with concurrent shoulder disorders were found. Team physicians can be reassured that infraspinatus atrophy is a common finding in high-performing tennis players and, if asymptomatic, does not appear to significantly compromise performance.
© 2015 The Author(s).
... To this end, the following secondary aims were pursued: (1) to identify the bone landmarks of the LTSN course in preparations of formalin-fixed cadaveric shoulders, (2) to measure the SSSA in dry scapulae, (3) to evaluate the occurrence of a particular type of scapular notch among the dry scapulae. (4) to calculate the Fn value based on the magnitude of SSSA with regard to the prevalence of ISA in chosen throwing sports, as given in the literature: i.e., beach volleyball − 34% [22] and tennis − 52% [50]. ...
... The most important finding of our study is the disclosure of a potential relationship between the anatomical course of LTSN, expressed as SSSA and the aetiology of ISA in throwing sports. Neurogenic ISA affects between 4.4 and 52% of baseball, volleyball and female tennis players [4,17,22,46,50]. ...
Introduction:
Although the pathomechanism of isolated infraspinatus atrophy (ISA) in throwing sports is known to be traction, it is unclear why only some players are affected. One likely explanation is that the infraspinatus pulling force exerted by its contracture generate the compressive resultant component force (Fn) compressing the lateral trunk of the suprascapular nerve (LTSN) against the edge of scapular spine. This paper makes two key assumptions (1) the course of LTSN in relation to the scapular spine, defined as the suprascapular-scapular spine angle (SSSA) is the key individual anatomical feature influencing the Fn magnitude, and thus potentially ISA development (2) SSSA is correlated with scapular notch type.
Materials and methods:
The bone landmarks of the LTSN course were identified in 18 formalin-fixed cadaveric shoulders, and the SSSA was measured in 101 dry scapulae. The correlation between the SSSA and suprascapular notch type was evaluated. The Fn value was simulated mathematically based on the values of the SSSA of 101 dry scapulae and the prevalence of ISA in chosen throwing sports, as given in the literature: i.e., beach volleyball - 34% (group A1 - 34%; group A2-remaining 66% of scapulae) and tennis - 52% (group B1 - 52%; group B2-remaining 48% of scapulae).
Results:
The mean SSSA value was 44.57° (± 7.9) and Fn 79 N (± 13.1). No statistically significant correlation was revealed between suprascapular notch type and SSSA. Groups A1 and B1 possessed significantly lower SSSA values (p < 0.000) and significantly higher Fn magnitude (p < 0.000) than groups A2 and B2 respectively. The average difference of Fn was 28.1% between group A1 and A2 and 31% between group B1 and B2.
Conclusions:
The SSSA has a wide range of values depending on the individual: the angle influencing the magnitude of the compressive resultant force Fn on the LTSN at the lateral edge of the scapular spine via contraction of the infraspinatus muscle. The prevalence of ISA in throwing sports may be correlated with the SSSA of the LTSN. However, further combined clinical, MRI or/and CT studies are needed to confirm this.
... 12 In addition, Witvrouw et al 13 detected evidence of suprascapular neuropathy affecting only the infraspinatus in 25% of the Belgian men's national volleyball team. Both of these studies are consistent with the estimated prevalence among a cohort of skilled German volleyball players, (33%) reported by Holzgraefe et al. 14 Although IS has been described in baseball players, 15 tennis players, fencers, weight lifters, and other overhead athletes, 1 the condition is much less common in these populations (eg, IS has been estimated to occur in only 4.4% of major league baseball players). 15 Despite these findings, no theory has yet been advanced that satisfactorily explains the observed association between volleyball and selective atrophy of the infraspinatus. ...
... Both of these studies are consistent with the estimated prevalence among a cohort of skilled German volleyball players, (33%) reported by Holzgraefe et al. 14 Although IS has been described in baseball players, 15 tennis players, fencers, weight lifters, and other overhead athletes, 1 the condition is much less common in these populations (eg, IS has been estimated to occur in only 4.4% of major league baseball players). 15 Despite these findings, no theory has yet been advanced that satisfactorily explains the observed association between volleyball and selective atrophy of the infraspinatus. 16 quantified the upper limb kinematics and kinetics of 14 healthy female Division 1 collegiate volleyball athletes while spiking and serving (athletes at all positions were tested). ...
Objective Infraspinatus syndrome (IS) results from injury to the suprascapular nerve. For reasons that are poorly understood, volleyball players are at greater risk of developing IS than are athletes who compete in other overhead sports. Differences between the shoulder kinematics of volleyball-related overhead skills and those skills demanded by other overhead sports might explain the pronounced prevalence of IS among volleyball athletes.
Design Observational, laboratory-based, cross-sectional study.
Setting The American Sports Medicine Institute.
Participants Fourteen healthy female Division 1 collegiate volleyball athletes.
Methods Upper limb biomechanics of 14 healthy female Division 1 collegiate volleyball athletes while spiking and serving were quantified, then compared to the results from data previously obtained from female baseball pitchers and tennis players.
Results Although the general movement pattern at the shoulder girdle is qualitatively similar for the upper limb skills required by a variety of overhead sports, volleyball spiking and serving result in greater shoulder abduction and horizontal adduction at the moment of ball contact/release than do baseball pitching or tennis serving.
Conclusion The authors suggest that the unique scapular mechanics which permit the extreme shoulder abduction and horizontal adduction that characterise volleyball spiking and serving place anatomically predisposed volleyball athletes at increased risk for developing cumulative traction-related injury to the suprascapular nerve at the level of the spinoglenoid notch.
... 10,11 A retrospective study found that 4.4% of asymptomatic major league pitchers demonstrated atrophy of the infraspinatus muscle. 12 ...
Background
The prevalence of suprascapular neuropathy is higher than previously estimated. Recent literature highlights a myriad of treatment options for patients ranging from conservative treatment and minimally invasive options to surgical management. However, there are no comprehensive review articles comparing these treatment modalities.
Objective
The purpose of this review article is to summarize the current state of knowledge on suprascapular nerve entrapment and to compare minimally invasive treatments to surgical treatments.
Methods
The literature search was performed in Mendeley. Search fields were varied redundant. All articles were screened by title and abstract and a preliminary decision to include an article was made. A full-text screening was performed on the selected articles. Any question regarding the inclusion of an article was discussed by 3 authors until an agreement was reached.
Results
Recent studies have further elucidated the pathoanatomy and described several risk factors for entrapment ranging. Four studies met our inclusion criteria regarding peripheral nerve stimulation with good pain and clinical outcomes. Two studies met our inclusion criteria regarding pulsed radiofrequency and showed promising pain and clinical outcomes. One study met our inclusion criteria regarding transcutaneous electrical nerve stimulation and showed good results that were equivalent to pulsed radiofrequency. Surgical treatment has shifted to become nearly all arthroscopic and surgical outcomes remain higher than minimally invasive treatments.
Conclusions
Many recently elucidated anatomical factors predispose to entrapment. A history of overhead sports or known rotator cuff disease can heighten a clinician’s suspicion. Entrapment at the suprascapular notch is more common overall, yet young athletes may be predisposed to isolated spinoglenoid notch entrapment. Pulsed radiofrequency, peripheral nerve stimulation, and transcutaneous electrical nerve stimulation may be effective in treating patients with suprascapular nerve entrapment. Arthroscopic treatment remains the gold-standard in patients with refractory entrapment symptoms.
... Repetitive overhead or overuse activities can damage the suprascapular nerve by traction or entrapment and result in a painless Infraspinatus atrophy as reported in 52% of female tennis players, 33% in volleyball players, 34% beach volley ball and 4% in baseball pitchers. Despite the infraspinatus atrophy, the effect on the athletes'performance is very limited [3,[18][19][20][21][22] . Recent studies report tightening of the spinoglenoid ligament during extreme range of motion particularly when internal rotation is combined with adduction or abduction, due to its insertion into the posterior glenohumeral joint capsule. ...
Suprascapular nerve entrapment at the spinoglenoid notch by a ganglion cyst results in the paralysis of the terminal motor branch of the nerve, with isolated atrophy of the infraspinatus muscle, loss of strength in external rotation, and posterior shoulder pain. Increased awareness of this nerve compression is paramount in order to avoid the stage of irreversible infraspinatus muscle wasting and long term disability. Magnetic resonance imaging scan, electromyography and nerve conduction velocity studies can confirm the diagnosis and lead to an early arthroscopic nerve decompression and favorable functional results. We present a rare case of spinoglenoid ganglion cyst compression of the distal suprascapular nerve and discuss the recent developments in anatomy, aetiology, diagnosis, and review the treatment and current trends in the management of this condition.
... Secondly, the ISP muscle atrophy occurs commonly in overhead sports athletes [19]. In previous study, atrophy of the ISP muscle in athletes is caused by entrapment of the suprascapular nerve. ...
Rotator cuff tears in young overhead sports athletes are rare. The pathomechanism causing rotator cuff tears in young overhead athletes is different from that in aged patients. The purpose of this study was to investigate rotator cuff tear characteristics in young overhead sports athletes to reveal the pathomechanism causing these injuries. This study included 25 overhead sports athletes less than 30 years old with atraumatic rotator cuff tears necessitating repair. Rotator cuff tear characteristics were evaluated intraoperatively, including rotator cuff tear shape and injured rotator cuff tendon. Clinical outcome measures were assessed before surgery and at the final follow-up. In this study, 22 patients reported minimal to no shoulder pain and returned to sports without significant complaints at last follow-up. The isolated infraspinatus tendon was most often injured; the incidence rate of the tear at this site was 32% (8 cases). In the deceleration phase of overhead motion, the eccentric contraction force of the ISP (infraspinatus) tendon peaks and the increased load leads to injury at the ISP tendon. The pathomechanism of rotator cuff injuries in young overhead athletes might be not only internal or subacromial impingement, but also these mechanisms.
... [17][18][19] The incidence of infraspinatus tears that is secondary to nerve injury has been shown to be especially high among athletes involved in overhead activities such as volleyball or baseball. 20,21) Because atrophy of the muscles can be induced by tears or by nerve injuries, the two etiologies require differentiation to avoid misdiagnosing or neglecting the conditions. We assessed the patients' preoperative MRIs and found that no masses suggestive of impingement around the suprascapular nerve were found. ...
Background: Isolated infraspinatus tear is very rare and clinical features are not as well known, therefore the purpose of this study was to evaluate clinical characteristics and outcomes of isolated infraspinatus tear that authors experienced. Methods: Authors reviewed 288 cases of full-thickness rotator cuff tear involving infraspinatus between 2010 and 2015, and retrospectively analyzed six cases of isolated infraspinatus tear. Perioperative clinical characteristics, postoperative functional outcomes of 6 months were investigated. Functional evaluation included visual analogue scale (VAS), range of motions, American Shoulder and Elbow Surgeons (ASES) score, and Constant score. Results: Calcific tendinitis was accompanied in 4 cases (66.7%). Three of them received steroid injection or aspiration or extracorporeal shockwave therapy. Mean preoperative pain VAS was 7.1 (range, 5-9), and mean postoperative pain VAS at 6 months later was 1.6 (range, 0-5). Preoperative muscle strength by isokinetic muscle performance test showed 52% deficit of abduction and 37.6% deficit of external rotation. All 6 patients had arthroscopic repair of the infraspinatus tendon. All the patients at the 6 months follow-up exhibited clinical improvement in the Constant score (67.8 [range, 45-77] to 89.3 [range, 81-100], p
... Two of the external rotator muscles, the infraspinatus and the teres minor, muscles of the rotator cuff, are also thought to be very important in the dynamic stability of the glenohumeral joint. Together with the other two muscles of the rotator cuff (subscapularis and supraspinatus), they appear to be fundamental in maintaining the humeral head centred in the glenoid surface, when powerful arm movements are performed during the acceleration phase of overhead throws or swimming skills 6 .A lack of strength in these muscles may induce instability in the glenohumeral joint and allow excessive translation of the humeral head during overhead arm movements [7][8][9] . Thus because it is very important to maintain an adequate balance between external and internal shoulder rotators, specific exercises for strength development of the external rotator muscles are fundamental for injury prevention [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] as swimmers and throwers will perform a large number of repetitions of ballistic shoulder internal rotations during their sporting career. ...
Background: The shoulder external rotator muscles and the different portions of the trapezius muscle have never been studied in exclusivity. However, the literature has provided several exercises which have been used in this study.
Purpose: To quantify electromyographic activity of the shoulder external rotator muscles and the upper, middle and lower trapezius in seven exercises. Methods: 20 healthy males performed 7 exercises in random order. Surface electromyography was recorded for the posterior deltoid, infraspinatus, teres minor, upper, middle and lower trapezius. Results: The four prone exercises presented the highest levels of EMG activation in the External Rotators Synergy (the average activation of arm external rotator muscles group) and in the Trapezius Synergy (the average activation of the three portions of trapezius). The infraspinatus muscle obtained the highest activation values in exercises 1 (prone horizontal abduction at 90° with full external rotation, thumb up ), 4 (prone external rotation at 90º abduction and elbow at 90º), and 5 (side-lying ER with elbow on the trunk). The highest activation level of the teres minor muscle was found in Exercise 1. Conclusions: The four prone exercises demonstrated the highest EMG activity in the shoulder, considering both the external rotator muscles and the trapezius. However, if the focus of the strength training process is mainly to strengthen the two external rotator muscles of the rotator cuff, with an adequate intramuscular coordination pattern for the trapezius, the side lying ER with the elbow resting on the trunk seems to be the most appropriate exercise.
... Two of the external rotator muscles, the infraspinatus and the teres minor, muscles of the rotator cuff, are also thought to be very important in the dynamic stability of the glenohumeral joint. Together with the other two muscles of the rotator cuff (subscapularis and supraspinatus), they appear to be fundamental in maintaining the humeral head centred in the glenoid surface, when powerful arm movements are performed during the acceleration phase of overhead throws or swimming skills 6 .A lack of strength in these muscles may induce instability in the glenohumeral joint and allow excessive translation of the humeral head during overhead arm movements [7][8][9] . Thus because it is very important to maintain an adequate balance between external and internal shoulder rotators, specific exercises for strength development of the external rotator muscles are fundamental for injury prevention [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] as swimmers and throwers will perform a large number of repetitions of ballistic shoulder internal rotations during their sporting career. ...
... e atrophy of the infraspinatus has been clinically recognized as corresponding to a suprascapular nerve palsy [1]. e suprascapular nerve is sensory and motor in nature, and it provides motor innervations to the infraspinatus and supraspinatus muscles [2,3]. Atrophy of the infraspinatus muscle is an uncommon pathology, usually observed in professional athletes [4]. ...
Background
The isolated atrophy of the infraspinatus muscle is an uncommon clinical alteration, generally secondary to the selective lesion of the suprascapular nerve related to sport activities, especially in professional volleyball players. The lesion of the suprascapular nerve can cause kinesthetic deficits. The assessment of kinesthesia is determined by the ability to detect joint movement and has been traditionally conducted by measuring the Threshold of Perception of Passive Motion (TPPM).Objective
The goal of the present study was to compare the TPPM among a group of healthy individuals (control group), a group of World League volleyball players with atrophy of the infraspinatus muscle on the dominant side, and group of athletes with no shoulder pathologies.Design, setting and participantsObservational study at a controlled research laboratory at the Brazilian Volleyball Training Center (CDV – Saquarema). 12 healthy non-athlete controls, 12 athletes with atrophy of the infraspinatus muscle, and 12 athletes without the atrophy.InterventionsA proprioception-testing device passively moved the shoulder and participants were instructed to respond as soon as movement was detected (TPPM) by pressing a button-switch. EEG and electromyographic (EMG) activities were recorded simultaneously. Response latency was established as the delay between the stimulus (movement) and the response (button press). The time-frequency dynamics of the EEG was analyzed.ResultsAn analysis of variance indicated a significant latency reduction (p
... Em função da assimetria que caracteriza essas acções, um paradigma muito utilizado para identificar as adaptações no perfil muscular introduzidas pela prática de acções de lançamento, consiste na comparação dos valores de ratio RE:RI nos dois ombros de cada sujeito. Dessa forma, um ratio RE:RI mais reduzido no ombro dominante foi observado em lançadores de basebol (Hinton, 1988;Wilk et al., 1993Wilk et al., , 2002Codine, Bernard, Pocholle, Benaim, Brun, 1997;Ellenbecker & Mattalino, 1997;Ellenbecker, Roetert, Bailie, Davies, Brown, 2002;Noffal, 2003;Cummins, Messer, Schafer, 2004), jogadores de voleibol (Alfredson, Pietila, Lorentzon, 1998;Wang, Macfarlane, Cochrane, 2000), jogadores de badmington (Ng & Patrick, 2002) e em tenistas (Koziris, Kraemer, Triplett et al., 1991;Chandler, Kibler, Stracener, Ziegler, Pace, 1992;Cohen, Mont, Campbell, Vogelstein, Loewy, 1994;Codine et al., 1997;, 2003Gozlan, Bensoussan, Coudreuse et al., 2006). Essa alteração de ratio RE:RI deve-se normalmente a valores de força de rotação interna superiores no ombro dominante sem que se verifiquem alterações significativas da força de rotação externa. ...
Resumo O principal objectivo do presente artigo é caracterizar o perfil muscular em termos de força/mobilidade dos músculos envolvidos na rotação do ombro em atletas praticantes de acções de lançamento. Os lançamentos constituem uma família de gestos técnicos desportivos muito comum. A grande mobilidade do ombro e a amplitude, intensidade e natureza repetitiva dos seus movimentos nas acções de lançamento aumenta o risco de lesão. Assim, nestes atletas é necessário encontrar um compromisso entre mobilidade e potência no ombro e estabilidade funcional. Por outras palavras, é necessário garantir um equilíbrio adequado entre os músculos rotadores internos e os seus antagonistas, os músculos rotadores externos, principalmente os músculos da coifa dos rotadores. O ratio entre a força de rotação externa e a força de rotação interna (RE:RI ratio), medida em dinamómetros isocinéticos, e a amplitude de movimento, medida por goniometria, em atletas de diferentes desportos são apresentados e discutidos. Os valores de RE:RI ratio observados no ombro dominante de praticantes de acções de lançamento são normalmente mais baixos que os valores de referência, e isso depende de um aumento da força de rotação interna sem aumentos correspondentes na força de rotação externa. Em relação à amplitude de movimentos, o ombro dominante desses atletas apresenta maior amplitude de rotação externa, e uma redução na amplitude de rotação interna e de rotação total. Essas adaptações predispõem o atleta para instabilidade do ombro e aumentam o risco de lesão. O fortalecimento e o desenvolvimento da capacidade de alongamento destes músculos devem constituir premissas que contribuam para a gestão de um binómio mobilidade/estabilidade articular mais adequado às exigências do ombro de um atleta que repetirá muitas acções de lançar na sua carreira desportiva. Abstract The main purpose of this article is to characterize the shoulder rotator muscle profile (the strength/mobility characteristics) in overarm throwing athletes. The overarm throw is a very common pattern in several sports. The great mobility of the shoulder joint and the amplitude, intensity and repetitive nature of its motion in overarm skills lead to a high risk of injury. In these athletes it is necessary to find a compromise between shoulder mobility and power and functional stability. In other words, it is essential to guarantee an adequate balance between the internal rotator muscles accelerating the arm and their antagonists, the external rotator muscles. The ratio between the external and internal rotation force (RE:RI ratio), measured through isokinetic dynamometer, and the range of motion (ROM), measured through goniometry, in athletes from different sports, are presented and discussed. The values of RE:RI ratio observed in the dominant shoulder of overarm athletes are usually lower, and this is dependent on an increase in the arm internal rotation strength without changes of the same magnitude in the external rotation strength. Concerning the ROM, the dominant shoulder in overarm athletes presents higher ROM of external rotation, and a decrease in the ROM of internal rotation and in the total rotation arc. These adaptations predispose the athlete to shoulder instability and injury. Specific exercises for stretching and strength development of the external rotator muscles are fundamental to the shoulder balance necessary for injury prevention, since these athletes will perform massive repetitions of ballistic movements of shoulder internal rotation during their sport career.
... A avaliação da força isocinética vem sendo usada como uma rotina que permite acompanhar e despistar desequilíbrios musculares no ombro, quantificando o ratio entre a força dos rotadores externos e a força dos rotadores internos (ratio RE:RI). Estudos prévios propuseram que a medição do ratio RE:RI pode ser um instrumento útil para identificar desequilíbrios musculares no ombro de atletas (Brown, Niehues, Harrah, Yavorsky, Hirshman, 1988;Wilk, Andrews, Arrigo, Keirns, Erber, 1993;Wilk et al., 2002;Ellenbecker & Mattalino, 1997;Ellenbecker & Roetert, 2003 (Hinton, 1988;Wilk et al., 1993Wilk et al., , 2002Codine, Bernard, Pocholle, Benaim, Brun, 1997;Ellenbecker & Mattalino, 1997;Ellenbecker, Roetert, Bailie, Davies, Brown, 2002;Noffal, 2003;Cummins, Messer, Schafer, 2004), jogadores de voleibol (Alfredson, Pietila, Lorentzon, 1998;Wang, Macfarlane, Cochrane, 2000), jogadores de badmington (Ng & Patrick, 2002) e em tenistas (Koziris, Kraemer, Triplett et al., 1991;Chandler, Kibler, Stracener, Ziegler, Pace, 1992;Cohen, Mont, Campbell, Vogelstein, Loewy, 1994;Codine et al., 1997;Gozlan, Bensoussan, Coudreuse et al., 2006). (Greenfield, Donatelli, Wooden, Wilkes, 1990;Kuhlman, Iannotti, Kelly, Riegler, Gevaert, Ergin, 1992 (Ruivo, 2009) Os judocas registaram valores de força isocinética superiores aos do grupo controlo em ambos os movimentos, rotação interna e rotação externa, e em ambaas as velocidades 60°/s e 180°/s. ...
Introduction: Patellar taping is frequently used by physiotherapists to reduce pain and enhance neuromuscular recruitment in patients with patellofemoral disorders. Its application can lead to an inhibition or facilitation of the neuromuscular activity; therefore, the vastus lateralis inhibition taping technique is commonly introduced in the rehabilitation program to induce an inhibition in the vastus lateralis muscle and create neuromuscular balance. Purpose: Evaluate the effect of the vastus lateralis inhibition taping technique on electromyographic (EMG) activity in the vastus lateralis (VL), vastus medialis obliquus (VMO) and VMO/VL ratio. Relevance: The development and research of the effectiveness of the inhibition techniques in the patellafemoral rehabilitation program is a current need in the physiotherapy intervention. Methodology: Thirty young healthy women (20±1.5 years) without patellofemoral pain syndrome volunteered for this study. Electromyographic activity was collected during an isometric muscular contraction made at 30 and 45 degrees of the knee flexion performed in the squat exercise, with and without vastus lateralis inhibition taping Results/discussion: In spite of the results suggesting a decrease in the EMG activity of the VL in both amplitudes evaluated, this difference was only statistically significant at 30 degrees of the knee flexion (p=0.01). There were no statistically significant differences in the EMG activity of the VMO (p>0.05) muscle and VMO/VL (p>0.05).Conclusions: The vastus lateralis inhibition taping technique might lead to a decrease in the electromyographic vastus lateralis activity; as a result, this intervention must be used in the rehabilitation of the patellofemoral dysfunction. However, further research is needed to evaluate the effectiveness of the vastus lateralis inhibition taping in the presence of the patellafemoral pain syndrome.
... e atrophy of the infraspinatus has been clinically recognized as corresponding to a suprascapular nerve palsy [1]. e suprascapular nerve is sensory and motor in nature, and it provides motor innervations to the infraspinatus and supraspinatus muscles [2,3]. Atrophy of the infraspinatus muscle is an uncommon pathology, usually observed in professional athletes [4]. ...
THE GOAL OF THE PRESENT STUDY IS TO COMPARE THE ELECTROPHYSIOLOGICAL CORRELATES OF THE THRESHOLD TO DETECTION OF PASSIVE MOTION (TTDPM) AMONG THREE GROUPS: healthy individuals (control group), professional volleyball athletes with atrophy of the infraspinatus muscle on the dominant side, and athletes with no shoulder pathologies. More specifically, the study aims at assessing the effects of infraspinatus muscle atrophy on the cortical representation of the TTDPM. A proprioception testing device (PTD) was used to measure the TTDPM. The device passively moved the shoulder and participants were instructed to respond as soon as movement was detected (TTDPM) by pressing a button switch. Response latency was established as the delay between the stimulus (movement) and the response (button press). Electroencephalographic (EEG) and electromyographic (EMG) activities were recorded simultaneously. An analysis of variance (ANOVA) and subsequent post hoc tests indicated a significant difference in latency between the group of athletes without the atrophy when compared both to the group of athletes with the atrophy and to the control group. Furthermore, distinct patterns of cortical activity were observed in the three experimental groups. The results suggest that systematically trained motor abilities, as well as the atrophy of the infraspinatus muscle, change the cortical representation of the different stages of proprioceptive information processing and, ultimately, the cortical representation of the TTDPM.
... Visible atrophy has been documented as having an incidence of 4.4% (8 of 183) in professional starting pitchers. 61 The mechanism for seemingly isolated muscle atrophy is unknown. Repeated, forceful eccentric muscular contraction has been shown to be associated with motor nerve injury. ...
The shoulders of those involved in repeated forceful overhead throwing undergo a range of neural, muscular, and skeletal adaptations. Knowledge of these normal adaptations may be helpful for the understanding of the prevention and treatment of injury in these athletes. This paper summarizes the current literature regarding these adaptations, and their relation to performance and pathology are presented along with relevant clinical implications. Throwing athletes show alterations in the strength ratio of their internal rotation (IR) compared with external rotation such that IR is enhanced and external rotation remains unchanged (in comparison with their nonthrowing arm). Typical scapular postural changes are seen (often IR and anterior tilting of the scapula) in the throwing arm; the humeral cortical and trabecular bones are thickened and there is often greater humeral retrotorsion. Torsional changes are, however, variable. Throwers have a higher incidence of injury to their suprascapular nerve, which may help explain their relative external rotational weakness. There is some evidence that the posterior inferior capsule is thickened in throwing athletes.
Background
Suprascapular nerve (SSN) entrapment in volleyball players leads to infraspinatus (ISP) muscle atrophy and weakness of abduction and external rotation (ER) of the shoulder.
Purpose
To assess functional outcome after arthroscopic extended decompression of SSN in the spinoglenoid notch and suprascapular notch in a group of volleyball athletes.
Study Design
Case series; Level of evidence, 4.
Methods
Volleyballers who underwent arthroscopic SSN decompression were analyzed retrospectively. Assessment tools consisted of range of motion and ER strength on Lovett scale and postoperative ER strength measured by dynamometer, Constant-Murley score (CMS), and visual evaluation of ISP muscle recovery by assessing muscle bulk.
Results
The study included 10 patients (9 male and 1 female). The mean age was 25.9 years (range, 19-33) and mean follow-up was 77.9 months (range, 7-123). The mean range of postoperative ER at 90° of abduction (ER2) was 105.6° (88°-126°) and 108.5° (93°-124°) for the contralateral side, while ER2 strength was 8 ± 2.6 and 12.65 ± 2.8 kg ( P < .01) respectively. Mean CMS was 89.9 (84-100). In 5 cases, there was complete recovery of ISP muscle atrophy whereas 2 patients had partial recovery and 3 had none.
Conclusion
Arthroscopic SSN decompression in volleyball players improves shoulder function, but results of ISP recovery and ER strength are variable.
Peripheral nerve injuries in the upper extremities may be common in throwing athletes as the throwing motion places extreme stress on the dominant arm. The combination of extreme stress along with repetitive microtrauma from throwing uniquely places the throwing athlete at elevated risk of upper extremity peripheral nerve injury. However, because symptoms can be non-specific and frequent co-exist with pathology in the upper extremity, the diagnosis of peripheral nerve injury is often delayed. Diagnosis of peripheral nerve injuries may require a combination of history and physical exam, diagnostic imaging, electrodiagnostic testing, and diagnostic ultrasound guided injections. The primary management should include physical therapy focusing on throwing mechanics and kinetic chain evaluation. However, some athletes require surgical intervention if symptoms do not improve with conservative management. The purpose of this focused narrative review is to highlight upper extremity peripheral neuropathies reported in throwing athletes and to provide an overview of the appropriate clinical diagnosis and management of the throwing athlete with a peripheral nerve injury.
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Background
The teres minor (TMi) muscle exposed relatively high activity during the acceleration and deceleration phases of the throwing motion, compared to the infraspinatus muscle. However, few studies have identified teres minor (TMi) muscle activity in intervention exercises. The purpose of this study was to investigate TMi muscle activities in different horizontal adduction (HADD) positions in the quadruped horizontal abduction (HABD) exercise. This study hypothesized that TMi muscle activity would differ in response to resistance application across different horizontal adduction positions.
Materials and methods
Nineteen collegiate baseball players volunteered their participation. Raw EMG activity of the TMi muscle along with 7 different muscles attached to the scapula on the dominant-side were collected, and normalized by each of the corresponding maximum voluntary isometric contractions (% MVIC). All subjects performed manual isometric resistance HABD exercises at 90° and 135° of abduction with three HADD angles in the quadruped position: 1) coronal, 2) scapular, and 3) sagittal plane. EMG data were also collected from rhythmical concentric contraction of HABD at 90° of abduction in the quadruped position.
Results
TMi muscle activity was significantly greater with the arm positioned in the coronal plane than that of the scapular and sagittal planes (41, 26, and 17% MVIC respectively) (P < 0.05).
Conclusion
The present study demonstrated that TMi muscle activity varied depending on horizontal adduction positions.
Suprascapular neuropathy is an increasingly-recognized cause of shoulder pain and weakness in throwing athletes. Timely diagnosis and management are required to restore function, reduce pain, and allow the athlete to return to sport. We describe the pertinent anatomy and pathophysiology involved in suprascapular neuropathy, clinical evaluation, imaging and diagnostic testing, surgical indications, our preferred operative techniques, and a summary of the reported postoperative outcomes.
Background
Previous studies have reported visually observed apparent muscle atrophy in the infraspinous fossa of the dominant arm of overhead athletes. Several mechanisms have been proposed as etiological factors, including eccentric overload, compressive spinoglenoid notch paralabral cysts, and cumulative tensile suprascapular neurapraxia.
Purpose
To report the prevalence of apparent infraspinatus atrophy in male professional tennis players and to determine whether the suspected atrophy correlates with objectively measured weakness of external rotation.
Study Design
Cross-sectional study; Level of evidence, 3.
Methods
A total of 153 male professional tennis players underwent a musculoskeletal screening examination that included visual inspection of the infraspinous fossa. Infraspinatus atrophy was defined as hollowing or loss of soft tissue bulk inferior to the scapular spine in the infraspinous fossa of one extremity that was visibly different from the contralateral extremity. This finding was observed and independently agreed upon by both an orthopaedic surgeon and a physical therapist during the examination. Also assessed were rotator cuff instrument-assisted manual muscle testing, visual observation of scapular kinesis (or motion), and glenohumeral joint range of motion for internal and external rotation and horizontal adduction.
Results
In the 153 players, dominant-arm infraspinatus atrophy was observed in 92 players (60.1%), and only 1 player (0.7%) was identified with nondominant infraspinatus atrophy. A Pearson correlation showed a significant relationship between the presence of dominant-arm infraspinatus atrophy and dominant-arm external rotation strength measured in neutral abduction/adduction (at the side) ( P = .001) as well as between the presence of dominant-arm infraspinatus atrophy and bilateral external rotation strength measured at 90° of glenohumeral joint abduction ( P = .009 for dominant arm and .002 for nondominant arm). No significant correlation was found with scapular dyskinesis, glenohumeral range of motion, or instrument-assisted manual muscle testing of the supraspinatus (empty-can test).
Conclusion
Visually observed infraspinatus muscle atrophy is a common finding in the dominant shoulder of asymptomatic male professional tennis players and is significantly correlated with external rotation weakness. This condition is present in uninjured players without known shoulder pathology and is not related to glenohumeral joint internal rotation, total rotation range of motion, or scapular dysfunction. Players with visually observed infraspinatus atrophy should be evaluated for external rotation strength and may require preventive strengthening.
Suprascapular neuropathy is a potential source of shoulder pain and functional limitation that can present secondary to various etiologies including entrapment or compression. Cystic lesions arising from a labral or capsular tear can compress the nerve along its course over the scapula. Nerve traction is theorized to arise from chronic overhead athletics or due to a retracted rotator cuff tear. The diagnosis of suprascapular neuropathy is based on a combination of a detailed history, a comprehensive physical examination, imaging, and electrodiagnostic studies. Although the anatomic course and variations in bony constraint are well understood, the role of surgical treatment in cases of suprascapular neuropathy is less clear. Recent reviews on the topic have shed light on the outcomes after the treatment of suprascapular neuropathy because of compression, showing that surgical release can improve return to play in well-indicated patients. The incidence of compressive neuropathy is quite high in the overhead athletic cohort, but most patients do not show clinically relevant deficiencies in function. Surgical release is therefore not routinely recommended unless patients with pain or deficits in strength fail appropriate nonsurgical treatment.
Suprascapular nerve (SSN) pathology remains a relatively rare entity. In case of isolated, confirmed and compression related pathology the necessary treatment is evident—decompression of the nerve. However, the SSN correlations with associated lesions, particularly with massive rotator cuff tears, are controversial. This chapter highlights the current status concerning this subject.
Muscle atrophy in shoulders with rotator cuff tendon tears is a negative prognosticator, associated with decreased function, decreased reparability, increased retears after repair, and poorer outcomes after surgery. Muscle edema or atrophy within a neurologic distribution characterizes denervation. Because most nerve entrapments around the shoulder are not caused by mass lesions and show no nerve findings on routine MR imaging sequences, pattern of muscle denervation is often the best clue to predicting location of nerve dysfunction, which narrows the differential diagnosis and guides clinical management. The exception is suprascapular nerve compression in the spinoglenoid notch caused by a compressing cyst.
The use of musculoskeletal testing in sports medicine is a widespread practice, typically with a dual goal of injury prevention and performance enhancement. Knowledge regarding sport-specific normative results of musculoskeletal tests is important for the optimal interpretation of test findings in individual populations of athletes. Sport-specific descriptive data aids in the interpretation of these tests and helps to define characteristic adaptations inherent in certain homogenous athletic populations. The purpose of this chapter is to present the current methods and descriptive findings of a tennis-specific musculoskeletal screening examination used for elite junior and professional tennis players.
Infraspinatus muscle atrophy is common in professional volleyball players, but it is unclear whether commonly observed strength and proprioception deficits can be reversed with training. Fifty‐four participants were recruited into an infraspinatus atrophy group (IAG, n = 18) and a non‐atrophy group (NAG, n=18) of elite volleyballers plus a healthy non‐athletic control group (CG, n = 18). IAG were trained with a progressive, specific shoulder external rotator strengthening routine for 32 sessions over 8 weeks. Shoulder external rotation peak torque (SERPT) and threshold to detect passive movement (TTDPM) and joint position sense (JPS) were measured before and after the intervention. At baseline, no significant difference was detected in strength or proprioception between the injured and control groups, but the normal athletes were stronger and had better proprioception than either IAG or CG (p < 0.001). IAG (d = 2.78) and NAG (d = 0.442) improved strength significantly after training. IAG improved TTDM and JPS (p < 0.001, d = ‐ 0.719 and ‐2.942, respectively) but were still worse than NAG (p < 0.001). Elite volleyball players with Infraspinatus muscle atrophy have strength and proprioception deficits which can be improved by a specific exercise program to normal but not elite athlete control levels.
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A 28-year-old male presents with pain over the posterior aspect of his dominant right shoulder. He does not report any acute injury. He likes to play cricket at amateur level and has been unable to bowl with his right arm due to “loss of power” and weakness for the last 4 months. Clinical examination reveals tenderness over the posterior glenohumeral joint line along with wasting over the infraspinatus fossa. There is marked weakness on objective testing of infraspinatus.
Infraspinatus atrophy (IA) is much more prevalent in overhead sports compared with the general population. Its exact aetiology in this group of athletes remains unclear and definitive associations with pathology and performance have not yet been reached. The aim of this systematic review is to present the evidence on IA in overhead athletes focussing on the proposed mechanisms of suprascapular neuropathy and its associations with shoulder pathology and performance. A thorough literature search via Medline, EMBASE and Scopus was performed. From the nine articles identified, the majority of authors propose suprascapular nerve (SN) injury at the spinoglenoid notch; however, the suprascapular notch has also been suggested as a potential site of injury. With regard to the exact mechanism of suprascapular neuropathy, the majority of authors propose repeated traction of the nerve during extreme shoulder abduction and horizontal adduction and/or eccentric contractions of the infraspinatus. In the limited relevant literature, convincing links between IA and performance or shoulder pathology have not been identified. IA in overhead sports is most likely of multi-factorial aetiology. Important questions about IA and its significance in overhead sports remain unanswered and more biomechanical and prospective studies are warranted to provide further insights into this athletic injury.
Die veränderte Position bzw. Bewegung der Skapula wird als Skapuladyskinesie bezeichnet. Klinisch ist diese v. a. durch ein Abheben des medialen Skapularands sowie eine fehlende Außenrotation und posteriore Kippung beim Anheben des Arms gekennzeichnet. Das primäre Winging wird dabei aus ätiopathogenetischer Sicht in einen neurologischen, einen knöchernen und einen Weichteiltyp unterteilt. Die Kompressionsneuropathien stellen insgesamt eine seltene Ursache für Schultergürtelbeschwerden dar. Bei Hochleistungsathleten in Überkopfdisziplinen müssen sie jedoch als wichtige Differenzialdiagnose bei anhaltendem Schulterschmerz in Betracht gezogen werden. Nervenläsionen skapulothorakaler und skapulohumeraler Nerven ereignen sich zumeist im Rahmen eines Traumas. Sowohl Nervenrekonstruktionen und Dekompressionen als auch Muskeltransferoperationen bei irreparablen Muskelläsionen stehen zur effektiven Behandlung zur Verfügung, bedürfen jedoch einer besonderen operativen Expertise. Pathologische Formveränderungen betreffen sowohl die knöcherne Formgebung der Skapula als auch die periskapuläre Muskulatur, Rippen und Wirbelkörper. Klinisch äußern sich diese Ätiopathologien sehr unspezifisch mit Impingement-artigen Beschwerden der betroffenen Schulter. Beim Incisura-scapulae-Syndrom handelt es sich um ein neuronales Kompressionssyndrom des N. suprascapularis im Bereich der Incisura scapulae sowie der Basis der Spina scapulae. Pathophysiologische Folgen sind v. a. die fettige Infiltration und die muskuläre Atrophie von M. supraspinatus und/oder M. infraspinatus.
Background:
Neuralgic amyotrophy (NA) was first described in 1948. Traditional literature describes a painful attack with sudden onset, followed by paresis, with varied outcomes. Recent studies have suggested NA is currently underdiagnosed. However, a large number of studies detailing NA originate from a small group of sources. Our study compared the onset, diagnosis, investigation, and treatment of all neurologic shoulder conditions to provide comparable data for these studies.
Methods:
Data were collected from 60 patients (81.6% male; median age, 41.5 years) during a 78-month period. Patients with a diagnosis of a neurologic disorder of the shoulder with confirmatory electromyogram (EMG) studies were included.
Results:
NA was diagnosed in 18 patients before the EMG investigation. Of the clinically diagnosed NA patients, only 5 (27.8%) had EMG findings supportive of NA. A further 5 patients with a clinical diagnosis other than NA were diagnosed with NA after EMG findings. Overall, 10 patients (16.6%) in our study were diagnosed with NA after EMG studies. Only 4 (40.0%) reported a sudden onset attack associated with NA. Supraspinatus and infraspinatus were involved in 9 patients (90.0%), suggesting a predictable distribution of muscle involvement.
Conclusions:
These results suggest that NA is overdiagnosed and does not warrant the increased attention suggested by recent articles. The current study also highlights a necessity to perform EMG investigations in all cases of suspected NA because the accuracy of the clinical assessment is poor.
Die Kompressionsneuropathie des N. suprascapularis stellt insgesamt eine seltene Ursache für Schultergürtelbeschwerden dar. Bei Hochleistungsathleten in Überkopfdisziplinen muss sie jedoch als wichtige Differenzialdiagnose bei anhaltendem Schulterschmerz in Betracht gezogen werden. Bei Persistenz von Beschwerden, nach ausgeschöpfter konservativer Therapie oder der bildgebend gesicherten Diagnose einer Kompression ist die chirurgische Dekompression in Betracht zu ziehen. Chirurgisch stehen offene und effektive arthroskopische Techniken zur Verfügung.
The suprascapular nerve
is a mixed motor and sensory nerve that innervates the glenohumeral joint and the surrounding posterior shoulder girdle. Entrapment of the suprascapular nerve
is a rare but increasingly recognized disease entity that contributes to pain and weakness in the posterior shoulder region. While suprascapular nerve
entrapment is predominantly found in overhead athletes that perform repetitive activities in an abducted and externally rotated position, iatrogenic injury to the nerve has also been reported following common shoulder procedures and in patients with large and massive rotator cuff tears. As such, it is important for the surgeon to have a detailed understanding and appreciation of the anatomic arrangement and course of the suprascapular nerve
, its variability, the biomechanics with shoulder movement, and important diagnostic considerations that can effect decision-making and intervention.
Neurovascular disorders must be considered during the evaluation of any patient with a condition related to the shoulder. The purpose of this chapter is to describe the most common neurovascular disorders that cause shoulder dysfunction and to provide a detailed description of the relevant physical examination maneuvers that can be used to guide the clinician towards an appropriate diagnosis and treatment regimen.
Nerve injuries around the shoulder in athletes are uncommon causes of pain and dysfunction. Athletes involved in overhead sports appear to be at increased risk. Recognition of this uncommon and frequently misdiagnosed condition is important as delayed treatment may lead to irreversible changes and cause impairment in the athlete. The goal of this chapter is to review in a comprehensive form anatomy and pathophysiology of the nerve injury, describe the typical clinical scenario and physical exam, contemplate a differential diagnosis of sources of shoulder pain, and list the diagnostic tools available; nonoperative and operative treatment options are described with special attention to arthroscopic techniques.
The following nerve injuries and specific associated syndromes about the shoulder in athletes will be reviewed: axillary nerve and the suprascapular nerve.
The aims of our study were to compare the dominant (DOM) and non-dominant (NDOM) shoulders of high-level volleyball athletes and identify possible associations of shoulder adaptations with spike speed (SS) and shoulder pathology. A total of 22 male volleyball players from two teams participating in the first division of the Cypriot championship underwent clinical shoulder tests and simple measurements around their shoulder girdle joints bilaterally. SS was measured with the use of a sports speed radar. Compared with the NDOM side, the DOM scapula was more lateralised, the DOM dorsal capsule demonstrated greater laxity, the DOM dorsal muscles stretching ability was compromised, and the DOM pectoralis muscle was more lengthened. Players with present or past DOM shoulder pain demonstrated greater laxity in their DOM dorsal capsule, tightening of their DOM inferior capsule, and lower SS compared with those without shoulder pain. Dorsal capsule measurements bilaterally were significant predictors of SS. None of the shoulder measurements was associated with team roles or infraspinatus atrophy, while scapular lateralisation was more pronounced with increasing years of experience, and scapular antetilting was greater with increasing age. Adaptations of the DOM shoulder may be linked to pathology and performance. We describe simple shoulder measurements that may have the potential to predict chronic shoulder injury and become part of injury prevention programmes. Detailed biomechanical and large prospective studies are warranted to assess the validity of our findings and reach more definitive conclusions.
Zusammenfassung
Der Schultergürtel, als exponierte anatomische Struktur, stellt beim Sportler eine prädisponierte Region für akute Verletzungen dar, da bei Stürzen die obere Extremität häufig zum Abfangen genutzt wird und somit der Schultergürtel die einwirkende Kraft abfängt. Aber auch direkte Anprallverletzungen können bei entsprechender Krafteinwirkung zu Verletzungen führen.
Neben akuten Verletzungen sind chronische Überlastungssituationen für Einschränkungen der Funktion und Leistungsfähigkeit des Sportlers verantwortlich. Repetitive Bewegungen und Belastungen z.B. bei Wurfsportarten zeigen ein typisches Schädigungsmuster.
Ein wesentlicher Teil in der Behandlung von Leistungssportlern sind das Verständnis für mögliche Pathologien, die Notwendigkeit einer zügigen Diagnostik bei Risikosportarten sowie der häufig langen Rehabilitationsphasen, insbesondere nach operativer Therapie. Im Rahmen dieses Artikels werden diese Aspekte beleuchtet und diskutiert.
Objectives:
To retrospectively assess the qualitative and quantitative high-resolution 3-T magnetic resonance imaging (MRI) findings in nonsymptomatic baseball pitcher draft picks.
Methods:
Institutional review board-approved and HIPAA compliant study. Three-Tesla MRI of the dominant shoulder of 19 asymptomatic baseball pitcher draft picks and detailed clinical examination was performed before contract signing. Two radiologists performed independently qualitative and quantitative evaluation of shoulder structures. Descriptive statistics were performed.
Results:
Sixty-eight percent (13/19), 32% (6/19), and 21% (4/19) of the baseball pitcher draft picks showed tendinopathy, partial thickness tendon tear of the supraspinatus, and acromioclavicular joint osteoarthritis, respectively. Glenohumeral subluxation, glenoid remodeling, and Bennett lesion were present in 53% (10/19), 79% (15/19), and 21% (4/19) of the subjects, respectively. Interclass coefficient was 0.633 to 0.863 and κ was 0.27 to 1.
Conclusions:
In asymptomatic baseball pitcher draft picks, 3-T MRI frequently shows abnormalities involving rotator cuff tendons, the coracohumeral, inferior glenohumeral, labrum, and osseous structures.
The recognition of peripheral nerve injury (PNI) is important as it can be associated with significant morbidity if not properly diagnosed and treated. PNI occur in sporting activities, war, civilian trauma, and as a complication of surgery. Awareness of the prevalence of peripheral nerve injury is essential if it is to be appropriately included in the differential diagnosis. This chapter reviews injury to the upper extremity nerves with special attention paid to areas of vulnerability, typical sensory and motor deficit patterns, and specific treatment issues.
Brachial plexopathies of various etiologies are commonly discussed in the literature; however, recurrent painless shoulder weakness is an uncommon event, especially in an otherwise healthy adult man. A designated Naval F/A-18 E/F aviator presented with acute right-sided, painless shoulder girdle weakness that initially presented 2 yr earlier in a similar fashion. Extensive medical workups during both episodes did not reveal any identifiable cause. This case report discusses the most common etiologies of shoulder weakness. Additionally, we discuss the aviator's most recent presentation and evaluation for acute shoulder weakness. Lastly, we propose a hypothesis as to the cause of the patient's symptoms based on a review of the literature.
Purpose of review: Overhead athletes test the limits of shoulder girdle function and frequently seek treatment for improved participation or return to their sport. This review article highlights the most pertinent recent studies concerning the function, pathology, diagnosis, and treatment of the thrower's shoulder.
Recent findings: Modern research strategies for understanding the unique characteristics of the thrower's shoulder include pathologic correlation studies, cadaver modeling, biomechanical motion and strength analysis, radiographic and arthroscopic observation, and clinical outcomes investigations. Recent studies reveal that decreased proprioceptive sensation, rotator cuff muscle strength imbalance, differential fatigue after pitching performances, increased glenohumeral translation, and increased glenohumeral external rotation with internal rotation deficit are present in the throwing shoulder. The primary challenge for the clinician interpreting the physical examination and radiographic findings of these athletes is discerning the point at which normal adaptation becomes pathologic change. Current understanding of the phenomenon of internal impingement supports a link between translational instability, range-of-motion changes, and forces exerted on the labrum during the cocking phase of throwing. Recent clinical studies report less than satisfactory results with thermal capsulorrhaphy for symptomatic subluxation or multidirectional instability in overhead athletes and report that arthroscopic Bankart repair is less effective for returning athletes to overhead sports than in other sports.
Summary: Diagnosis of pathology in the thrower's shoulder requires understanding of specific physical and radiographic findings common to these patients. Nonoperative management is the mainstay of treatment. Operative indications are less clear and invasive procedures should be reserved for refractory conditions.
Beach volleyball is an overhead sport with a high prevalence of infraspinatus muscle atrophy of the hitting shoulder.
Infraspinatus muscle atrophy seems to be caused by a repetitive traction injury of the suprascapular nerve. Early pathological findings might be assessed with surface electromyography (EMG) and nerve conduction velocity (NCV) measurements.
Cross-sectional study; Level of evidence, 3.
Fully competitive professional beach volleyball players were assessed with a structured interview, shoulder examination, strength measurements (external rotation and elevation), and neurophysiological examination (surface EMG and NCV of the infraspinatus and supraspinatus muscles and the suprascapular nerve, respectively) during the Beach Volleyball Grand Slam tournament 2010 in Klagenfurt, Austria.
Thirty-five men with an average age of 28 years were examined. Visible infraspinatus atrophy was found in 12 players (34%), of which 8 (23%) had slight atrophy and 4 (11%) had severe atrophy. External rotation (90%; P < .006) and elevation strength (93%; P = .03) were significantly lower in the hitting shoulder. Electromyography revealed a higher activation pattern in the infraspinatus muscle of the hitting arm in players with no or slight atrophy (P = .001) but a significantly lower activation pattern in players with severe atrophy (P = .013). Nerve conduction velocity measurements showed a significant higher latency and lower amplitude in the hitting shoulder of the total study group and the subgroup with infraspinatus atrophy.
Professional beach volleyball players have a high frequency of infraspinatus atrophy (34%) and significantly reduced shoulder strength of the hitting shoulder. These findings are not associated with demographic factors. Electromyography and NCV measurements suggest a suprascapular nerve involvement caused by repetitive strain injuries of the nerve. External rotation strength measurements and NCV measurements can detect a side-to-side difference early, while EMG may show compensation mechanisms for progressive damaging of the suprascapular nerve and, as a result, loss of infraspinatus muscle strength.
The antioxidant activity of astaxanthin against paraquat (PQ) induced oxidative stress in primary cultures of chicken embryo fibroblasts (CEF) was assessed. Activities of the antioxidant enzymes superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) were measured as indices of oxidative stress. CEF incubated with 0.25 mM PQ for 18 h exhibited increased SOD and CAT activities and decreased GSH-Px activity compared to control. Incorporation of astaxanthin (0.1–10 nM) into 0.25 mM PQ treated CEF reduced SOD and CAT activities. Astaxanthin (0.1–10 nM) returned GSH-Px activity to its control value. CEF grown in astaxanthin enriched media (0.1–10 nM) were also oxidatively stressed by exposure to 0.25 mM PQ. In these studies, astaxanthin enrichment (0.1–10 nM) of the medium returned all antioxidant enzyme activities to those seen in control cells.
The aim of the study was to evaluate effects of shoulder overuse in elite symptomatic or asymptomatic gymnasts.
This was a university-based sport traumatology research, a cohort study, with a control group comparison. Patients included were: 21 elite male gymnasts performing in the Italian National team for at least 10 years and a control group of 10 patients (20 shoulders) of the same age and sex, randomly selected among a healthy non-athletic population who underwent shoulder MRI. Magnetic resonance imaging without contrast were performed to all participants and clinical findings were summarized. Two experienced musculoskeletal radiologists interpreted each MRI scan for multiple variables (rotator cuff tendons, labral signal, capsule), including type of measurements performed on soft tissues (muscles, tendons) to assess global modifications of the shoulders.
Signal abnormalities were detected in 36/36 (100%) gymnasts' shoulders, and in 4/20 (20%) of the controls. Sixteen of 36 (44.4%) shoulders had findings consistent with SLAP tears, bilateral in four patients; anteroinferior labrum lesions were identified in 10/36 (27.7%) shoulders, as compared with none (0%) in the controls. Eight of 36 (22%) shoulders had findings consistent with partial- or full-thickness tears of the rotator cuff as compared with none (0%) of the controls. Increased thickness of rotator cuff tendons and hypertrophy of rotator cuff muscles and deltoid muscles were recorded: such reports were symmetrical between dominant and non dominant arms, and increased when compared to controls.
Gymnasts' shoulders are significantly different from those of the general population. MRI findings, especially SLAP tears, and hypertrophy are symmetrical. SLAP tears seem to be responsible of most early retirement.
Atrophy of both the supraspinatus and infraspinatus muscles is usually caused by chronic rotator cuff tear, but may also derive from suprascapular nerve entrapment at the spinoglenoid notch. Isolated infraspinatus muscle atrophy is uncommon, and typically associates with suprascapular nerve entrapment occurring distal to the spinoglenoid notch. However, isolated atrophy of the infraspinatus muscle due to insertional tear of the infraspinatus tendon may also occur. We present a case of a 43-year-old male with isolated infraspinatus muscle atrophy and fatty degeneration following an isolated full-thickness infraspinatus tendon tear at the insertion site on the humerus. While it is important to rule out other causes of infraspinatus muscle atrophy, such as concomitant rotator cuff tendon/muscle pathology or suprascapular nerve palsy, we present this case to increase awareness of this uncommon clinical presentation and the potential implications for treatment.
The shoulder is one of the most complex joints in the human body and, as such, presents an evaluation and diagnostic challenge. The first steps in its evaluation are obtaining an accurate history and physical examination and evaluating conventional radiography. The use of other imaging modalities (eg, ultrasound, magnetic resonance imaging and computed tomography) should be based on the type of additional information needed. The goals of this study were to review the current limitations of evidence-based medicine with regard to shoulder examination and to assess the rationale for and against the use of diagnostic physical examination tests.
制度:新 ; 文部省報告番号:甲1988号 ; 学位の種類:博士(人間科学) ; 授与年月日:2005/1/26 ; 早大学位記番号:新3915
Beach volleyball is an Olympic overhead sport. It is not well known which clinical and imaging findings are normal and which are associated with symptoms.
There are typical clinical and imaging findings in the hitting shoulders of fully competitive professional beach volleyball players, as compared with their nonhitting shoulders.
Cross-sectional study; Level of evidence, 3.
During the Beach Volleyball Grand Slam Tournament in Klagenfurt, Austria, 84 professional players (54 men, 30 women) underwent a questionnaire-based interview and a complete physical examination, including scoring and sonography of both shoulders. Twenty-nine players had shoulder MRIs.
The mean age of the athletes was 28 years. Atrophy of the infraspinatus muscle was found in 30% of the hitting shoulders, and it was not typically recognized by the players. The absolute Constant score was significantly lower in the hitting shoulder (87 versus 93 points, P < .0001). Average external rotation strength was decreased in the hitting shoulder (8.2 versus 9.5 kg, P < .0001). There were more abnormalities on the sonography of the hitting shoulder (1.7 versus 0.4, P < .0001) and in the same shoulders on MRI than on sonography (P = .0231). Compression of the suprascapular nerve was not observed. Pain in the hitting shoulder was present in 63% of the players, without clear correlations to the investigated clinical and imaging parameters.
The prevalence of infraspinatus muscle atrophy in professional beach volleyball players is 30%. The typical, fully competitive player has subjectively unrecognized decreased strength of external rotation and frequent unspecific shoulder pain. Therefore, abnormal clinical and imaging findings in the beach volleyball player should be interpreted with care.
High-intensity repetitive athletic activities may predispose the brachial plexus to repetitive stretch, compression, and subsequent injury, although painless shoulder weakness is a rare event.
The physical examination and electrodiagnostic findings in a series of United States Navy special warfare trainees who presented with acute painless shoulder weakness are presented, along with subsequent treatment and return-to-duty timeline.
Case series; Level of evidence, 4.
From August 2005 to August 2006, a total of 11 of 212 (5%) Navy Basic Underwater Demolition School trainees were identified with acute onset (<3 weeks) painless shoulder weakness without any prior shoulder injury. In all shoulders, symptoms began during a telephone pole lift-carry drill. All trainees underwent serial examinations, electrodiagnostic testing, and a comprehensive rehabilitation program.
Physical examination revealed universal weakness in flexion and abduction and electrodiagnostic studies confirmed injury to the C5-6 area of the brachial plexus (axillary, suprascapular, and musculocutaneous). All 11 patients were removed from training and started on a physical therapy program until functional recovery at a mean of 21 weeks after onset of symptoms (range, 12-24). All 11 resumed military activities; however, only 6 completed the Navy Basic Underwater Demolition School program.
In physically intense training or athletic environments, injuries to the upper brachial plexus may present with various forms of upper extremity dysfunction, including painless shoulder weakness. This information provides insight into a potentially debilitating shoulder problem and offers guidance on future training principles.
Baseball players place significant stress across their shoulders and elbows during the throwing motion, causing unique patterns of injuries in the overhead throwing athlete. Specific nerve injuries include suprascapular neuropathy, quadrilateral space syndrome, and cubital tunnel syndrome. Nonoperative treatment includes cessation of throwing and symptom management. As symptoms improve, athletes should start rehabilitation, focusing on restoring shoulder and trunk flexibility and strength. The final rehabilitation phase involves an interval throwing program with attention directed at proper mechanics, with the goal of returning the athlete to competitive throwing. Surgery may assist in a positive outcome in particular patients who fail to improve with nonoperative treatment. Additional indications for surgery may include more profound neuropathy and nerve compression by a mass lesion.
Lesions of the suprascapular nerve can occur at the supraspinatus notch (SSN) or at the spinoglenoid notch (SGN). Electromyographic (EMG), evaluation of the infraspinatus, and especially the supraspinatus muscles distinguishes SGN from SSN lesions. Three cases of SGN lesions, which are more common than SSN lesions, are presented.
The suprascapular nerve originates from the upper trunk of the brachial plexus or less frequently from the root of C5. It runs a short way and crosses the suprascapular notch. It innervates the supraspinatus muscle and the acromioclavicular and glenohumeral joints. Then, it crosses the lateral edge of the spine of the scapula passing through the spinoglenoid notch, and innervates the infraspinatus muscle. These are potential sites of injury to the suprascapular nerve. Three cases of suprascapular nerve entrapment causing an isolated infraspinatus muscle atrophy in volleyball players were studied. It is suggested the hypothesis that the nature of the smash, in which the athlete uses the arm violently, more than does in volleyball service or in the art of reception, is the key to the pathogenesis of the lesion in volleyball players.
Isolated and painless infraspinatus atrophy and weakness are described in two top-level volleyball players. EMG revealed isolated denervation of the infraspinatus muscle. One athlete continued playing and his clinical features have not changed. The other recovered her muscle bulk and strength after stopping playing. These findings were attributed to intense activity of the shoulder joint, without any direct trauma. On clinical grounds, we did not consider these cases as true examples of entrapment neuropathy. Pathogenesis was related to traction of the distal branch of the suprascapular nerve during the act of reception of the ball ("Manchete").
Background—Suprascapular nerve entrapment with isolated paralysis of the infraspinatus muscle is uncommon. However, this pathology has been reported in volleyball players. Despite a lack of scientific evidence, excessive strain on the nerve is often cited as a possible cause of this syndrome. Previous research has shown a close association between shoulder range of motion and strain on the suprascapular nerve. No clinical studies have so far been designed to examine the association between excessive shoulder mobility and the presence of this pathology. Aim—To study the possible association between the range of motion of the shoulder joint and the presence of suprascapular neuropathy by clinically examining the Belgian male volleyball team with respect to several parameters. Methods—An electromyographic investigation, a clinical shoulder examination, shoulder range of motion measurements, and an isokinetic concentric peak torque shoulder internal/external rotation strength test were performed in 16 professional players. Results—The electrodiagnostic study showed a severe suprascapular neuropathy in four players which affected only the infraspinatus muscle. In each of these four players, suprascapular nerve entrapment was present on the dominant side. Except for the hypotrophy of the infraspinatus muscle, no significant differences between the affected and non-affected players were observed on clinical examination. Significant differences between the affected and non-affected players were found for range of motion measurements of external rotation, horizontal flexion and forward flexion, and for flexion of the shoulder girdle (protraction); all were found to be higher in the affected players than the non-affected players. Conclusions—This study suggests an association between increased range of motion of the shoulder joint and the presence of isolated paralysis of the infraspinatus muscle in volleyball players. However, the small number of patients in this study prevents definite conclusions from being drawn.
A 30-year-old recreational baseball player developed dominant-sided infraspinatus atrophy and shoulder pain after throwing a baseball. Partial denervation of the infraspinatus muscle with delayed motor latency was documented. Isolated lesions of the branch to the infraspinatus may be more common than previously suspected, particularly in throwing athletes with shoulder pain.
The clinical features and preoperative and postopera tive electrodiagnostic studies were reviewed in two professional pitchers with a suprascapular neuropathy. These studies demonstrate that denervation of the infraspinatus and/or supraspinatus muscle is not al ways due to entrapment of the nerve at the suprascap ular or spinoglenoid notches, as is often proposed. Similar studies in healthy pitchers during spring training and again at midseason demonstrate that slowing of suprascapular nerve conduction is detectable in some cases as the season progresses.
Sagittal sections of a cadaver with the arm fixed in the acceleration phase of the pitching motion demon strate five possible sites of trauma to the suprascapular nerve. Mechanisms proposed to explain these progres sive, but potentially reversible, changes include consid eration of biomechanical factors as well as anatomical features. An alternative hypothesis to nerve trauma that explains this symptom complex is intimal damage to the axillary or suprascapular artery and subsequent production of microemboli which become trapped in the suprascapular nerve vasa nervorum.
Nerve lesions are frequently overlooked in the differential diagnosis of shoulder pain, and there have been few reports in the literature of injuries of the supracapsular nerve that involve only the infraspinatus. We report four cases of suprascapular nerve injuries which involve solely the infraspinatus in which each patient presented with shoulder pain and weakness. The diagnosis can be suspected by careful history and physical examination, but must be confirmed by the appropriate electrical studies. Our patients required 6 months to 1 year to regain full function, and isokinetic testing revealed near normal return of strength. Further diagnostic work-up and surgery may be necessary for those cases which fail to demonstrate satisfactory improvement in the expected time period.
We examined ninety-six top-level volleyball players from eight teams that competed during the 1985 European Championships, and twelve players were found to have asymptomatic isolated paralysis of the infraspinatus of the dominant side. Three players were studied with electromyography and Cybex-II isokinetic dynamometry. The results revealed denervation of the infraspinatus and approximately a 22 per cent loss of strength of the affected arm during external rotation. These findings were attributed to repeated stress due to stretching of the nerve during cocking of the arm and follow-through when the athlete was serving.
The aim of the present study was to evaluate the prevalence of latent and manifest suprascapular neuropathy in high-level male volleyball players. Thirty subjects were examined clinically and electrophysiologically. Suprascapular neuropathy, most probably at the level of the suprascapular notch, was demonstrated in 12 subjects, being latent in eight. Taking into account our clinical findings in a further 36 international-level players, a remarkably high overall prevalence of suprascapular nerve lesion of 33% (22 of 66 subjects) was found. All cases involved the side of the body with the player's smashing arm. These findings suggest that careful monitoring of suprascapular nerve function may be useful in high-performance volleyball players, as early diagnosis is essential to prevent more severe damage.
To describe a case of isolated infraspinatus atrophy due to suprascapular nerve entrapment by a labral ganglion cyst in a volleyball player and to propose a mechanism for its formation.
A female volleyball player was evaluated for shoulder pain and found to have atrophy of the infraspinatus muscle. Magnetic resonance imaging (MRI) showed a loculated ganglion cyst impinging on the suprascapular nerve.
Several etiologies for isolated infraspinatus atrophy in volleyball players are cited in the literature. It is suggested here that the rapid deceleration in the volleyball spike can result in a superior labral lesion (SLAP), which can lead to ganglion cyst formation. These ganglion cysts can then cause isolated infraspinatus atrophy by impinging on the suprascapular nerve at the spinoglenoid notch.
In one study, isolated infraspinatus atrophy was found in 12% of elite volleyball players. Since infraspinatus atrophy may result from impingement of the suprascapular nerve by ganglion cysts and not just traction injuries, imaging studies, such as an MRI, should be considered in the evaluation of these patients.
Selective denervation of the infraspinatus muscle producing weakness and wasting has been reported in certain sports (eg, volleyball and baseball). Nerve kinking or friction caused by excessive infraspinatus motion and compression by superior or inferior transverse scapular ligament or ganglions have been proposed as possible causes. However, in extreme abduction with full external rotation of the shoulder, the medial tendinous margin between the infraspinatus and supraspinatus muscles impinges strongly against the lateral edge of scapular spine, compressing the intervening infraspinatus branch of the suprascapular nerve. Spinaglenoid notchplasty has been performed in 5 elite volleyball players with infraspinatus neuropathy, allowing recovery of shoulder function in all patients and correction of infraspinatus muscle wasting. All returned to the same or higher level of volleyball by 8 months after surgery. An alternative cause of infraspinatus compromise in volleyball players is proposed and has been treated surgically with satisfactory outcome.
From 1985 to 1996, we observed 38 cases of isolated atrophy of the infraspinatus muscle in athletes; all were involved in volleyball at a competitive level. There were 20 men and 18 women with a mean age of 26 years (range, 15 to 27). At the time of the first examination, 35 of these athletes had no pain and were treated with exercises to strengthen the external rotators. The remaining three patients underwent surgery because of pain at the posterior aspect of the shoulder. Sixteen of the 35 players treated nonoperatively were reviewed at a mean follow-up of 5.5 years (range, 3 to 10). Thirteen were still involved in volleyball and three had retired symptom-free at the end of their careers. On physical examination, atrophy of the infraspinatus muscle was unchanged in all cases. The patients treated surgically were reviewed at a mean follow-up of 2 years. All of them were able to play volleyball at their preinjury levels, but one had pain at the anterior aspect of the shoulder after strenuous activity. Physical examination showed a notable reduction of the atrophy in one patient. Entrapment of the suprascapular nerve at the spinoglenoid notch is a usually painless syndrome that is frequently observed in volleyball players. Surgical treatment is indicated in the rare cases of painful neuropathies after careful patient selection.
Suprascapular nerve injuries at the spinoglenoid notch are uncommon. The true incidence of this lesion is unknown; however, it appears to be more common in athletes who participate in sports involving overhead activities. When a patient is being evaluated for posterior shoulder pain and infraspinatus muscle weakness, electrodiagnostic studies are an essential part of the evaluation. Electromyography will identify an injury to the suprascapular nerve as well as assist in localizing the site of injury. In addition, imaging studies are also indicated to help exclude other diagnoses that can mimic a suprascapular nerve injury. The initial management should consist of cessation of the aggravating activity along with an organized shoulder rehabilitation program. If the patient fails to improve with 6 months to 1 year of nonoperative management, surgical exploration of the suprascapular nerve should be considered. Release of the spinoglenoid ligament with resultant suprascapular nerve decompression may result in relief of pain and a return of normal shoulder function.
In baseball pitchers, injuries to the throwing arm are common due to the extreme stresses placed on the elbow and shoulder joints. These result in peripheral nerve syndromes including ulnar neuropathy at the elbow and suprascapular neuropathy at the shoulder. Recurrent trauma to the axillary artery causing aneurysm and thrombus formation may lead to distal ischemia and stroke. Careful evaluation is required to identify musculoskeletal, neurologic, and vascular causes of upper extremity symptoms in the throwing athlete.
Atrophy of infraspinatus muscle caused by suprascapular nerve entrapment is a typical disease of overhead sports such as volleyball, baseball and javelin. The chronic distress of suprascapular nerve infraspinatus branch may derive from nerve kinking and friction caused by an entrapment at the spino-glenoid notch, often repeated during external-rotation and abduction of shoulder. From 1999 to 2000 4 athletes, out of 143 professional baseball players, were found suffering from this disease. The diagnosis was confirmed by MNR and EMG, while a isokinetic test quantified a loss of strength in external-rotation and allowed a standard parameter for the treatment result evaluation. The 4 athletes were submitted to a non-invasive rehabilitation protocol, thanks to electrostimulation and isokinetic exercises, aiming at strengthening the extrarotator muscles and restoring a suited musclar balance. A subjective improvement was verified and confirmed by isokinetic test in all the players; moreover no surgery was needed.