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Knee joint muscle function after patellectomy: How important are the hamstrings?

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Knee joint muscle function after patellectomy: How important are the hamstrings?

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Abstract

Twenty-three patients who had undergone unilateral patellectomy were tested using the Cybex II isokinetic dynamometer 9 years postoperatively. The results were compared with the performance of the uninvolved joint. There was a good correlation between loss of the quadriceps muscle function and loss of the hamstrings muscle function at 60 deg/s (R = 0.7, P < 0.001). Patients who showed a loss of quadriceps function of less than 40% also maintained good hamstrings function. A good or excellent functional result could be expected in these patients. If the loss of quadriceps function was more than 40%, a proportional loss of flexion torque was seen, indicating a functional impairment of the knee joint muscles not solely attributable to the loss of the lever arm. Furthermore, all patients with a loss of peak flexion torque of more than 30% showed an unsatisfactory clinical result. The evaluation of the hamstrings muscles by measuring the peak flexion moment at 60 deg/s can therefore be used as a preoperative assessment and as a guideline for rehabilitation after patellectomy.

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Chapter
Mit der Entfernung der Patella gehen die wichtigen Funktionen der Zentralisierung der divergierenden Kräfte des Streckapparates, die möglichst reibungsarme Übertragung der Streckwirkung, die Verbesserung der Effizienz der Streckmuskulatur durch Vergrößerung des Momentarmes und der kosmetische Effekt auf die Kniegelenkskontur verloren. Der Eingriff hat damit fundamentale Auswirkungen auf die Kniegelenkfunktion, weshalb die Indikation sehr streng zu stellen ist. Die Erfolgsaussichten der Operation hängen vom Zustand der Streckmuskulatur, der Beweglichkeit sowie von eventuellen Vorschädigungen des Kniegelenks ab. Eine vorbestehende Schwächung des Quadrizeps-Muskels, degenerative Veränderungen des Femorotibial-Gelenks und eine Bewegungseinschränkung stellen somit ungünstige Voraussetzungen dar. Die Indikation zur Patellektomie wird beim schmerzhaften Patellofemoralgelenk infolge degenerativer Veränderungen, permanenter Subluxation oder Luxation, posttraumatischer Schädigung am häufigsten zu stellen sein. Die Operationstechnik sollte primär stabile Verhältnisse schaffen, um die Frühmobilisation einschließlich frühfunktioneller Quadrizepsaktivierung zu ermöglichen. Bei der Beurteilung der Ergebnisse ist neben der Verwendung üblicher Kniescores zur objektiven Dokumentation auch die instrumentelle Bewegungsanalyse empfehlenswert, da sie die funktionellen Einschränkungen durch die Patellektomie beim Gangablauf am besten dokumentieren kann.
Article
Periprosthetic fractures are a challenging problem in view of the demographic development and the increasing number of implanted prostheses. Most of these fractures occur postoperatively after a period of two to four years after implantation of a total knee arthroplasty. They are usually caused by traumata, implantation-specific factors and loosening of the prosthesis. Beside further risk factors osteopenia and a reduced mobility of the prosthesis predispose to these fractures. Numerous classifications which also include a loosening of the prosthesis in the fracture discription are an important tool for planning the therapy. Beside the conservative treatment, the stabilization of the fracture or changing the prosthesis should be considered. The treatment options of periprosthetic fractures of the knee joint are discussed in view of different initial situations with the aim of achieving a load-stable situation. Georg Thieme Verlag KG Stuttgart · New York.
Chapter
Die Prävalenz dieser Frakturen ist steigend, und sie sind daher bereits der dritthäufigste Grund für die Revision einer Hüftprothese. Periprothetische Frakturen werden in peri- und postoperative Frakturen unterteilt. Unzementierte Schäfte sind mit einem großen Risiko für eine periprothetische Fraktur verbunden. Daten aus der Mayo-Klinik zeigen ein Risiko für eine intraoperative Fraktur von 0,3 % für zementierte Schäfte und von 5,4 % für unzementierte Schäfte. Das Risiko einer postoperativen Fraktur für zementierte und unzementierte Schäfte wird mit 1,1 % angegeben. Das Risiko einer intraoperativen Fraktur steigt bei einer Wechseloperation auf 3,6 % für zementierte und 20,9 % für unzementierte Schäfte (Berry 1999). Das Gesamtrisiko für eine periprothetische Fraktur beträgt nach den Daten der Mayo-Klinik 4,1 %. Daten aus dem schwedischen Prothesenregister zeigen für das Gesamtkollektiv ein 10-Jahres- Risko von 0,64 % (Lindahl 2007). Die Einjahresmortalität des Gesamtkollektivs beträgt 13,1 % (Lindahl et al. 2006a).
Article
Aim of the study Is there a correlation between the timing of patellectomy after trauma in crush injuries and the clinical outcome? Methods Retrospective analysis of 21 patients who had undergone patellectomy after trauma. Results In 12 patients (57.1%) a primary patellectomy was performed within 4 weeks after the fracture; in the remaining 9 (42.9%) patients the procedure was performed after an average of 21 months (range 2–72). Nineteen patients could be followed up after 9.3 years (range 3–18). In 10 of these, patellectomy had been performed primarily. The HSS Knee Score was 68.4 points (range 39–83) on average for all patients. For patients with a primary patellectomy the score was 71 points (range 54–83), while for patients in whom the patellectomy was performed secondarily the score was 63.8 points (range 39–77). The evaluated ROM was 113.6° for all patients; in the primary group ROM was 122.5° (range 65–145°), and in the secondary group it was 103° (range 85–145°). The difference was not statistically significant for either parameter. Conclusion Primary reconstruction of the patella is recommended in multifragmentary fractures; if the outcome is poor, however, patellectomy should be considered early.
Article
The demographic developments and an increasing number of total knee replacements will lead to more periprosthetic fractures in the future. These fractures can be classified into intraoperative and postoperative. Revisions in particular are associated with a higher incidence of intra-operative fractures, specifically for the tibia and patella. Most fractures occur in the postoperative period with an average of 2–4 years after the primary procedure. Most commonly the femur is involved. The history and clinical examination as well as imaging are crucial for the treatment as loose components would significantly alter the treatment strategy. In this case a revision has to be carefully planned. In the majority of the cases the prosthesis is well fixed especially at the femur. An open reduction internal fixation (ORIF) can then be carried out. A stable situation must be achieved to provide early post-operative mobilization. Also an anatomic reduction should be achieved with correct alignment especially with respect to varus/valgus and rotation. Modern locked implants can provide this with good success also with the possibility of minimally invasive techniques and polyaxial screw positioning. Retrograde intramedullary devices can be a feasible alternative. Similar principles can be used for the tibia whereas the patella can be stabilized with tension band wiring in the case of good bone stock but still remains a problem in case of bad bone stock.
Article
The demographic developments and an increasing number of total knee replacements will lead to more periprosthetic fractures in the future. These fractures can be classified into intraoperative and postoperative. Revisions in particular are associated with a higher incidence of intra-operative fractures, specifically for the tibia and patella. Most fractures occur in the postoperative period with an average of 2-4 years after the primary procedure. Most commonly the femur is involved. The history and clinical examination as well as imaging are crucial for the treatment as loose components would significantly alter the treatment strategy. In this case a revision has to be carefully planned. In the majority of the cases the prosthesis is well fixed especially at the femur. An open reduction internal fixation (ORIF) can then be carried out. A stable situation must be achieved to provide early post-operative mobilization. Also an anatomic reduction should be achieved with correct alignment especially with respect to varus/valgus and rotation. Modern locked implants can provide this with good success also with the possibility of minimally invasive techniques and polyaxial screw positioning. Retrograde intramedullary devices can be a feasible alternative. Similar principles can be used for the tibia whereas the patella can be stabilized with tension band wiring in the case of good bone stock but still remains a problem in case of bad bone stock.
Article
Full-text available
We describe 83 knees (69 patients) which had had patellectomy for anterior knee pain (52), patellofemoral osteoarthritis (25) or comminuted fractures (6) between 1942 and 1978. The patients were questioned about their symptoms and the function of the operated knee 14 to 50 years after operation. In the group with anterior knee pain, 76% achieved good results and were satisfied with the operation. Only 54% of the osteoarthritis group had satisfactory relief of pain and most had progressive deterioration of function. Sixteen patients who had had unilateral patellectomy were assessed by dynamometry, ultrasound and radiography. The average quadriceps muscle power was 60% of that on the normal side although two patients had stronger muscles in their operated than in their unoperated legs.
Article
Eight healthy male subjects performed isokinetic maximum knee extensions from 90 degrees flexion to full extension in a CYBEX n apparatus at two different speeds (30° and 180° s(-1)). Using a planar biomechanical model of the patellofemoral joint, the patellar forces in the sagittal plane were quantified. At the slower speed the patellofemoral compressive force and the suprapatellar tendon force reached values of about 12 bodyweights while the infrapatellar tendon force did not exceed 9 bodyweights. At the faster speed, the corresponding force magnitudes were 7.5 bodyweights and 5.5 bodyweights. The force peaks occurred at the beginning of the extension movement between 65° and 75° of knee flexion and were a function of knee angle and knee extension strength. The magnitude of the patellar forces during isokinetic knee extension of maximum effort were compared to other knee extending activities and were found to be considerably higher than during walking, jogging, and cycling.
Article
Twenty cases of patellectomy for fracture and 14 cases of patellectomy for chondromalacia evaluated for postoperative strength, endurance, pain and functional complaints, revealed satisfactory results in 85% of the fracture group and 79% of the chondromalacia group. Some quadriceps weakness was usually present, but quadriceps strengthening overcame the loss of mechanical efficiency caused by patellectomy. A vigorous rehabilitation program should be followed for at least one year after surgery to secure the fullest recovery of function.
Article
Twenty-eight out of a group of 38 patients, who had undergone a patellectomy during the period 1950-70, were investigated clinically and radiologically. The results were compared with the subjective symptoms of the patients to see if there was a correlation. The follow-up period was 7.4 years on average. A good subjective result was reported by only six patients. The predominant subjective symptoms were weakness of the limb and pain on movement and/or exertion. The most usual findings were atrophy of the quadriceps muscle, crepitation, and palpation tenderness. The muscular power of the quadriceps was found to be greater than or equal to 75 per cent of the power of the intact knee in only seven cases (25 per cent).
Article
Thirty-three patients were evaluated after patellectomy for subjective complaints, objective physical findings, quadriceps strength, and knee motion during activities of daily living. Partial and complete patellectomy caused an equal loss of active and passive range of motion. Complete patellectomy resulted in greater ligament instability, quadriceps atrophy, and loss of quadriceps strength compared with partial patellectomy. Complete patellectomy casued a reduction in the degree of stance-phase flexion during level walking and negotiating stairs.
Article
One hundred seven patients were examined who had undergone patellectomies between 1965 and 1983 (113 patellectomies). The mean follow-up time was 10.5 years (3-17.5 years) and the average age of the patients 42.6 years. There were three distinct groups of operative techniques: (1) the purse-string technique in 40 patellectomies; (2) the vastus medialis technique in 24 patellectomies; (3) other techniques in 49 patellectomies. The indications for patellectomy were: chondromalacia, 56 cases; comminuted patellar fractures, 32 cases; arthritis, 17 cases; recurrent patellar dislocations, 8 cases. The patients were examined for pain, rage of motion, giving way, swelling, quadriceps strength, activity and cosmetic results (interview, physical examination, Cybex and radiographic study). In the purse-string technique group, 81% of the cases ended up with good or excellent results; in the vastus medialis group there were 79% and in the third group only 73% good or excellent results. Among the patellectomies for comminuted fractures, 75% had excellent results. The clinical outcome of patelletomy for arthritis is fair, for recurrent dislocation favorable, and for chondromalacia variable and not predictable.
Article
Ten cadaver legs were mounted on a loading frame, and normal values for quadriceps excursion and tibial force were established with a constant quadriceps tension. The mean excursion of the quadriceps was 66.2 +/- 5.51 millimeters from zero to 90 degrees of knee flexion. After examining each 10-degree increment of motion we found that the maximum excursion of the quadriceps (9.49 +/- 1.35 millimeters) occurred between 30 and 40 degrees. The minimum excursion of 5.40 +/- 0.67 millimeters was found between 80 and 90 degrees of knee flexion. Incremental excursion of the quadriceps during 10-degree increments of knee flexion showed a correlation coefficient of 0.94 when compared with mean tibial torque (p less than 0.001). Patellectomy decreased excursion of the quadriceps to 51.3 +/- 1.30 millimeters from zero to 90 degrees of knee flexion. Torque was decreased by roughly 40 per cent of maximum from zero to 40 degrees of knee flexion.
Article
Twenty-seven patients with 28 patellectomies were re-examined after an average of 20 years. Twelve knees rated as excellent, ten as good and six as fair. Even though 12 patients had strenuous work, only three patients had changed occupation. Quadriceps power was on average two-thirds that of the opposite limb. Radiographs showed incipient femoro-tibial arthrosis in four patients only.
Article
The patella contributes to the knee extension moment arm through the entire range of knee motion. Its contribution increases with progressive extension. In terms of extension moment, special modifications of transverse repair have no advantage over simple transverse approximation of the patellar ligament and quadriceps tendon, but transverse repair is superior to longitudinal repair. Depending on the technique of patellectomy defect repair, full postpatellectomy extension may require as much as a 30 per cent increase in quadriceps force. Tibial tubercleplasty can lengthen the extension moment arm and permit full extension with no greater force than that required in the knee before patellectomy. A 30 per cent increase in quadriceps force may be beyond the capacity of some patients, particularly those with long-standing intra-articular disease, those in advanced age, or those who have extension lag prior to operation. If patellectomy is indicated for this select group of patients, tibial tubercleplasty ought to be considered.
Article
The Cybex-II isokinetic dynamometer was used to measure quadriceps and hamstrings function after unilateral patellectomy in twelve patients. The interval between surgery and testing averaged twenty-six months (range, fourteen to forty-two months). Data on isokinetic and isometric performance were compared with those of the untreated limb and with those of subjects who had not been operated on but who had been matched by age, sex, and weight. On the side that had been operated on, the peak torque of the quadriceps was significantly decreased whereas the peak torque of the hamstrings was preserved. Deficits in time factors related to the development of tension and high-speed performance were documented, revealing abnormalities in both muscle groups. Although patellectomy was successful in achieving relief of pain in these patients, the results of the study confirmed that the function of the knee muscles was compromised postoperatively. The objective findings documented alterations in muscle function that correlated well with the functional limitations described by the patients.
Article
When patellectomy is performed, the objectives should include restoration of a moment arm, centralization of the extensor mechanism, adequate range of motion, and cosmesis. The cruciate repair of the extensor mechanism described in this report has been developed to meet the aforementioned objectives. Eight patients with 12 patellectomies described herein were examined with Cybex testing of the knee at a follow-up period of 18 months to 20 years (mean, 56 months). A four-quadrant tissue dissection of the patellar soft-tissue enclosure was reconstructed in a cruciform pants-over-vest fashion, with the superomedial flap containing the vastus medialis insertion on top. This "soft-tissue" patella attempts to provide a greater moment arm than simpler repairs. This study examines whether this construct restored the torque of extension while concomitantly facilitating centralization of the extensor mechanism. Cybex testing of both knees examined both extensor and flexor function with specific regard to the ratio of extensor to flexor forces. Patients with patellectomies had few subjective complaints, with a mean knee score of 94 (median, 100). The extensor torque was not completely restored and there was a moderate decrease in the quadriceps function, both subjectively and objectively as measured by Cybex testing. The authors also found that in patients with unilateral patellectomies, the ratios of extension to flexion function, a parameter not yet reported in the literature, were significantly different between the normal and patellectomized knees. The same extension to flexion ratios were seen in patients with bilateral patellectomies. Because patients with patellar pathology requiring patellectomy frequently have chronic and bilateral disease, comparative functional evaluation may be difficult.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
The authors are in disagreement with the literature on the results of patellectomy after comminuted fracture of the patella. They assessed retrospectively 17 patients who underwent unilateral total patellectomy between 1955 and 1980. Subjective and objective (clinical examination, radiologic examination and Cibex II studies) assessment was carried out for each patient using the contralateral healthy knee as a control. The results demonstrated 88% patient satisfaction, no ligamentous instability and no early arthrosis but a decrease in extensor muscle strength to 75% of normal. The authors conclude that total patellectomy is better tolerated and causes less morbidity than suggested in the literature.
Patellectomy after fracture: long-term
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  • Aj Aho
  • Kallio
Einola S, Aho AJ, Kallio P (1976) Patellectomy after fracture: long-term
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