Evaluation of Muscle Size and Fatty Infiltration with MRI Nine to Eleven Years Following Hamstring Harvest for ACL Reconstruction
ABSTRACT The long-term effect of hamstring tendon harvest for anterior cruciate ligament (ACL) reconstruction on muscle morphology is not well documented. Our hypothesis was that harvest of the hamstring tendons for ACL reconstruction would result in persistent loss of volume and cross-sectional area of the gracilis and semitendinosus muscles.
Magnetic resonance images were made of both limbs of ten patients nine to eleven years after they had ACL reconstruction with ipsilateral hamstring autograft. The volume of the individual thigh muscles bilaterally was calculated. The peak cross-sectional area and the cross-sectional area 7 cm proximal to the joint line was measured for the gracilis and semitendinosus muscles. Data were evaluated with use of the paired t test and Wilcoxon signed-rank test. The gracilis and semitendinosus muscles on the operatively treated side were evaluated for fatty infiltration and tendon regeneration.
The mean volume on the operatively treated side was 54.2% of that on the noninvolved side for the gracilis muscle and 58.5% for the semitendinosus muscle. A 7% decrease in quadriceps volume and an 8% increase in the volume of the long head of the biceps on the operatively treated extremity were noted. The semimembranosus muscle and short head of the biceps muscle showed no difference in volume. The gracilis and semitendinosus muscles also showed a decrease in peak cross-sectional area, a decrease in the cross-sectional area 7 cm proximal to the joint line, and evidence of fatty infiltration. There was variable evidence of tendon or scar formation within the tendon bed, with most patients having some tissue that blended into either the sartorius muscle or medial gastrocnemius fascia at a level proximal to the joint line.
At nine to eleven years after ACL reconstruction with ipsilateral hamstring autograft, the gracilis and semitendinosus muscles showed persistent atrophy on the operatively treated side with evidence of fatty infiltration and variability in tendon regeneration. There was also persistent atrophy of the quadriceps muscles and compensatory hypertrophy of the long head of the biceps.
Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.
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ABSTRACT: The purpose of this study was to assess activation patterns of medial (MH) versus lateral (LH) hamstrings in female athletes who had undergone ACL reconstruction (ACLR) using a hamstrings-graft during single-limb functional testing.Knee Surgery Sports Traumatology Arthroscopy 09/2014; DOI:10.1007/s00167-014-3333-6 · 2.84 Impact Factor
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ABSTRACT: The aim of this study was threefold: to investigate the incidence of sensory deficits after harvesting hamstrings autografts, to localise and measure the area of altered sensibility and to investigate the impact of any sensory deficit on the patients daily life. A consecutive series of sixty-one patients were examined for sensory deficits related to harvest of hamstrings tendons 10 years after having had an anterior cruciate ligament reconstruction. A neurological examination of the leg was performed to investigate for potential altered sensibility and to quantify the extent of the lesion. The patients answered the anterior knee symptoms (AKS) questionnaire and additional questions regarding impact on activities of daily life by any sensory deficit. Eighty-five per cent of the examined patients had sensory deficits-experienced as numbness (78 %) and paraesthesia (16 %)-distal to the site of tendon harvesting. The mean affected area was 70 (SD 62) cm(2). No patients experienced sensory deficit symptoms to such a degree that it affected their activities of daily life, but the group with sensory deficit had significantly more AKS than patients without sensory deficit, as evaluated by the AKS score (P = 0.02). The most commonly reported complaints were related to strenuous activities and kneeling knee position. This long-term evaluation shows that sensory deficit after hamstring tendons harvesting affects a majority of patients and is probably permanent. Most patients reported this as being only mildly bothersome, but they have significantly more AKS as assessed by the AKS questionnaire. In clinical practice, patients should be counselled prior to tendon harvesting on the incidence and characteristic of the sensory deficit along with other possible peri- and postoperative complications. Case series, Level IV.Knee Surgery Sports Traumatology Arthroscopy 01/2014; 23(4). DOI:10.1007/s00167-014-2871-2 · 2.84 Impact Factor
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ABSTRACT: In situ studies involving supraphysiological muscle lengths and relative positions have shown that connective tissue linkages connecting adjacent muscles can transmit substantial forces, but the physiological significance is still subject to debate. The present study investigates effects of such epimuscular myofascial force transmission (EMFT) in the rat calf muscles. Unlike previous approaches, we quantified the mechanical interaction between the soleus (SO) and the lateral gastrocnemius and plantaris complex (LG+PL) applying a set of muscle lengths and relative positions corresponding to the range of knee and ankle angles occurring during normal movements. In nine deeply anesthetized Wistar rats, the superficial posterior crural compartment was exposed, distal and proximal tendons of LG+PL and the distal SO tendon were severed and connected to force transducers. The target muscles were excited simultaneously. We found that SO active and passive tendon force was substantially affected by proximally lengthening of LG+PL mimicking knee extension (10% and 0.8% of maximal active SO force, respectively; p<0.05). Moreover, SO relative position significantly changed the LG+PL length-force relationship, resulting in non-unique values for passive slack-length and optimum-length estimates. We conclude that also for physiological muscle conditions, isometric force of rat triceps surae muscles is determined by its muscle-tendon unit length as well as by the length and relative position of its synergists. This has implications for understanding the neuromechanics of skeletal muscle in normal and pathological conditions, as well as for studies relying on the assumption that muscles act as independent force actuators. Copyright © 2014, Journal of Applied Physiology.Journal of Applied Physiology 12/2014; 118(4):jap.00703.2014. DOI:10.1152/japplphysiol.00703.2014 · 3.43 Impact Factor