Injuries in Muscle-Tendon-Bone Units: A Systematic Review Considering the Role of Passive Tissue Fatigue

Background: Low-cycle fatigue damage accumulating to the point of structural failure has been recently reported at the origin of the human anterior cruciate ligament under strenuous repetitive loading. If this can occur in a ligament, low-cycle fatigue damage may also occur in the connective tissue of muscle-tendon units. To this end, we reviewed what is known about how, when, and where injuries of muscle-tendon units occur throughout the body. Purpose: To systematically review injuries in the muscle-tendon-bone complex; assess the site of injury (muscle belly, musculotendinous junction [MTJ], tendon/aponeurosis, tendon/aponeurosis–bone junction, and tendon/aponeurosis avulsion), incidence, muscles and tendons involved, mechanism of injury, and main symptoms; and consider the hypothesis that injury may often be consistent with the accumulation of multiscale material fatigue damage during repetitive submaximal loading regimens. Methods: PubMed, Web of Science, Scopus, and ProQuest were searched on July 24, 2019. Quality assessment was undertaken using ARRIVE, STROBE, and CARE (Animal Research: Reporting In Vivo Experiments, Strengthening the Reporting of Observational Studies in Epidemiology, and the Case Report Statement and Checklist, respectively). Results: Overall, 131 studies met the inclusion criteria, including 799 specimens and 2,823 patients who sustained 3,246 injuries. Laboratory studies showed a preponderance of failures at the MTJ, a viscoelastic behavior of muscle-tendon units, and damage accumulation at the MTJ with repetitive loading. Observational studies showed that 35% of injuries occurred in the tendon midsubstance; 28%, at the MTJ; 18%, at the tendon-bone junction; 13%, within the muscle belly and that 6% were tendon avulsions including a bone fragment. The biceps femoris was the most injured muscle (25%), followed by the supraspinatus (12%) and the Achilles tendon (9%). The most common symptoms were hematoma and/or swelling, tenderness, edema and muscle/tendon retraction. The onset of injury was consistent with tissue fatigue at all injury sites except for tendon avulsions, where 63% of the injuries were caused by an evident trauma. Conclusion: Excluding traumatic tendon avulsions, most injuries were consistent with the hypothesis that material fatigue damage accumulated during repetitive submaximal loading regimens. If supported by data from better imaging modalities, this has implications for improving injury detection, prevention, and training regimens.

Hemangioma of First Extensor Compartment of the Wrist– A Rare Case Report

Introduction: Although upper extremity intramuscular hemangioma is a rare clinical entity, it poses considerable morbidity in the functional needs of an individual. The diagnosis of intramuscular hemangioma poses a diagnostic glitch. The combined radiological and histopathological assessment provides a complete understanding and diagnosis for the same. Every tumor follows an individualized protocol for its management. Case Report: A 15-year-old female presented with swelling over dorsal aspect of distal 1/3rd right forearm, which was 3 cm away from the articular surface of the right wrist from the past 5 years. There was no history of trauma or infection over the right wrist. Finkelstein’s test was negative, which rule out de Quervain’s tenosynovitis. The movements of the right wrist were unrestricted without any distal neurovascular deficit. MRI of her right wrist and hand suggested the presence of low flow vascular malformation within the musculotendinous junction of APL and EPB muscles. The patient underwent excision biopsy of the hemangiomatous lesion in toto without any neurological complications. No recurrence was noted in the follow-up period for 6 months. Conclusion: Being a benign vascular tumor, MRI provides the gateway to diagnose intramuscular hemangioma for early intervention to provide better functional results. The choice of definitive treatment for APL and EPB hemangioma was excision biopsy in toto which provided better functional results in our patient. Keywords: Hemangioma, intramuscular, abductor pollicis longus, extensor pollicis brevis, MRI, excision biopsy.

The anatomical variant of high soleus muscle may predispose to tendinopathy: a preliminary MR study

Purpose This study aimed to examine the anatomic variations at the level of the distal soleus musculotendinous junction and the possible association between the length of the free tendon and the development of symptomatic Achilles tendinopathy. Methods We retrospectively assessed 72 ankle MRI studies with findings of Achilles tendinopathy (study group, 26 females/46 males, mean age 52.6 ± 10.5 years, 30 right/42 left) and 72 ankle MRI studies with normal Achilles tendon (control group, 32 females/40 males, mean age 35.7 ± 13.7 years, 42 right/30 left side). We measured the distance from the lowest outline of the soleus myotendinous junction to the proximal outline of the Achilles tendon insertion (length of the free tendon, diameter a) and to the distal outline of the insertion (distance B). We also measured the maximum thickness of the free tendon (diameter c) and the distance between the levels of maximum thickness to the proximal outline of the Achilles tendon insertion (distance D). All measurements were assessed twice. Statistical analysis was performed using independent t test. Results Distances A and B were significantly larger in tendinopathic tendons (59.7 and 83.4 mm, respectively) than normal Achilles tendons (38.5 and 60.8 mm, respectively) (p = 0.001). Mean distance C was larger in tendinopathic than normal tendons (11.2 versus 4.9 mm). Distances C and D were significantly larger in males than females. There was no significant difference in the measurements between sides. Conclusion There is wide anatomical variation in the length of the free Achilles tendon. Tendinopathy may be associated with the thicker free part of the Achilles tendon. The anatomical variant of the high soleus musculotendinous junction resulting in a longer free Achilles tendon may be a predisposing factor to the development of tendinopathy.

Intratendinous Strain Variations of the Supraspinatus Tendon Depending on Repair Technique: A Biomechanical Analysis Regarding the Cause of Medial Cuff Failure

Background: Double-row (DR) and transosseous-equivalent (TOE) techniques for rotator cuff repair offer more stability and promote better tendon healing compared with single-row (SR) repairs and are preferred by many surgeons. However, they can lead to more disastrous retear patterns with failure at the medial anchor row or the musculotendinous junction. The biomechanics of medial cuff failure have not been thoroughly investigated thus far. Purpose: To investigate the intratendinous strain distribution within the supraspinatus tendon depending on repair technique. Study Design: Controlled laboratory study. Methods: Twelve fresh-frozen cadaveric shoulders were used. The intratendinous strain within the supraspinatus tendon was analyzed in 2 regions—(1) at the footprint at the greater tuberosity and (2) medial to the footprint up to the musculotendinous junction—using a high-resolution 3-dimensional camera system. Testing was performed at submaximal loads of 40 N, 60 N, and 80 N for intact tendons, after SR repair, after DR repair, and after TOE repair. Results: The tendon strain of the SR group differed significantly in both regions from that of the intact tendons and the TOE group at 40 N ( P≤ .043) and from the intact tendons, the DR group, and the TOE group at 60 N and 80 N ( P≤ .048). SR repairs showed more tendon elongation at the footprint and less elongation medial to the footprint. DR and TOE repairs did not provide significant differences in tendon strain when compared with the intact tendons. However, the increase in tendon strain medial to the footprint from 40 N to 80 N was significantly more pronounced in the DR and TOE group ( P≤ .029). Conclusion: While DR and TOE repair techniques more closely reproduced the strains of the supraspinatus tendon than did SR repair in a cadaveric model, they showed a significantly increased tendon strain at the musculotendinous junction with higher loads in comparison with the intact tendon. Clinical Relevance: DR and TOE rotator cuff reconstructions lead to a more anatomic tendon repair. However, their use has to be carefully evaluated whenever tendon quality is diminished, as they lead to a more drastic increase in tendon strain medial to the footprint, putting these repairs at risk of medial cuff failure.

Pectoralis Major Tendon Reconstruction at the Myotendinous Junction With Semitendinosus Allograft: An Operative Technique

Background: Pectoralis major (PM) tendon tears are a relatively uncommon injury that typically occurs in a young, active population during weightlifting or recreational sports. Musculotendinous junction and chronic PM tears often require tendon reconstruction due to inadequate remnant tendon stump or inability to reduce the remnant tendon stump to humeral footprint. Indications: We favor operative repair or reconstruction of PM tears in all young and active patients medically appropriate for surgery as supported by the literature. We present a technique for PM tendon reconstruction with semitendinosus allograft. This technique is applicable to musculotendinous junction and chronic tears. Technique: A modified deltopectoral approach is used. The PM tear is identified at the musculotendinous junction and the retracted muscle belly is mobilized. The PM tendon is reconstructed with a semitendinosus allograft using a Pulvertaft weave technique. The humeral footprint is prepped and the reconstructed tendon is properly tensioned and reduced. Fixation is performed with fibertapes loaded on 3 unicortical buttons. Postoperatively, the patient follows a graduated rehabilitation protocol. Results: There is a paucity of literature regarding outcomes of PM tendon reconstructions for musculotendinous junction tears. One study reported outcomes on 6 patients who had musculotendinous junction tears and underwent semitendinosus allograft reconstruction with a technique similar to ours. They report good clinical outcomes with high patient satisfaction regarding cosmetic outcome, return of strength, and overall satisfaction postoperatively. Discussion: It is our experience that the described technique for reconstruction of the PM tendon with semitendinosus allograft provides a viable option with good clinical outcomes for patients with PM ruptures at the musculotendinous junction.

FUNCTIONAL OUTCOME OF MODIFIED PUTTI PLATT PROCEDURE IN RECURRENT DISLOCATION OF SHOULDER – A RETROSPECTIVE ANALYSIS

Hand, which is considered to be an extension of brain and a tool for the execution of human intellect and will, owes much to the versatility of the movement of the shoulder for its placement on the desired spot of action. The shoulder, by virtue of its anatomy and biomechanics, is one of the most unstable and frequently dislocated joints, accounting for nearly 50% of all dislocations. Most of the recurrent dislocations of shoulder (96%) follow an initial signicant traumatic dislocation. There are two basic types of surgical approaches for shoulders with anterior instability: "anatomic" and "non-anatomic" repairs. With anatomic repairs, the goals are to restore the labrum toits normal position and to reestablish the appropriate tension in the shoulder capsule and ligaments. The goal of non-anatomic surgical procedures is to stabilize the shoulder by compensating for the capsulolabral and osseous injury with an osseous or soft-tissue checkrein that blocks excessive translation and restores stability. In Modied Putti Platt procedure, as done in our institute, after proper positioning and adequate exposure, the subscapularis muscle and capsule is incised at the musculotendinous junction. Aquadrangular unicortical graft, harvested from the iliac crest, is inserted fully into the trough made in the anterior glenoid, resulting in deepening of the glenoid articular surface. Subscapularis and the capsule are closed by double breasting, keeping the arm in external rotation. We did a retrospective analysis to assess the outcome of this procedure done in our institute. 102 patients were assessed and the required data were collected using hospital medical records, telephonic interview and direct clinicoradiological assessment. All the patients had positive apprehension test, pre- operatively. The mean Rowe score was 30.98 (standard deviation 5.846). The mean follow up duration was 44.52 months. 91 patients (89.2%) had no pain at last follow up duration and the rest had slight and occasional pain. All the patients were able to work above shoulder. The mean external rotation at 6 months follow up was 37.89° (SD 9.239), which increased to 65.88° (SD 8.967) at last follow up. The mean internal rotation at 6 months follow up was 61.18° (SD 4.623), which increased to 77.16° (SD 6.234) at last follow up. There was signicant improvement of Rowe's score post-operatively when compared to pre-operative Rowe's score. There was a signicant mean increase of 49.216 points post operatively with a correlation coefcient of +0.513. (p<0.05). All patients, at last follow up had a UCLA score of more than 27, with 96 patients (94.1%) had good clinical outcome (according to UCLA grading system). 6 patients had fair clinical outcome. 77 patients (75.5 %), according to Rowe score had good clinical outcome.12 patients (11.8%) had excellent outcome. 13 patients had fair clinical outcome. None of the patients who were operated in our institute had recurrence of dislocation. None of them were reoperated. 91 patients (89.2%) had negative apprehension with no evidence of subluxation. 10 patients (9.8%) had negative apprehension, but slight discomfort in abduction and external rotation. One person had positive apprehension test, but he was able to continue his activities of daily living and continued to engage in professional non contact sports, though at one level below; and he did not choose to undergo a reoperation. 6 patients, all aged more than 45 years, had clinicoradiological evidence of mild arthrosis of the shoulder joint. They are being treated conservatively with physical therapy and analgesics Mild donor site pain was there in 6 patients in the rst yr of surgery. This subsided with time with analgesics. None had evidence of donor site infection, and none had evidence of visceral injuries.

The Relevant Anatomy of the Biceps Tendon When Performing Tenodesis in Filipino Cadaveric Specimens

Background: Biceps tenodesis is a technique frequently performed in shoulder surgeries. Various techniques have been described, but there is no consensus on which technique restores the length-tension relationship. Restoration of the physiologic length-tension relationship has been correlated to better functional outcomes, such as decreased incidence of residual pain or weakness of the biceps. The objective of this study was to measure the anatomic relationship of the origin of the biceps tendon with its zones in the upper extremity. This would provide an anatomic guide or an acceptable placement of the tenodesis to reestablish good biceps tension during surgery. Methods: The study used nine adult cadavers (five males, four females) from the [withheld for blinded review]. Nine shoulder specimens were dissected and markers were placed at five points along each biceps tendon: (1) Labral origin (LO) (2) Superior bicipital groove (SBG) (3) Superior border of the pectoralis tendon (SBPMT) (4) Musculotendinous junction (MTJ) and (5) Inferior border of the pectoralis tendon (IBPMT). Using the origin of the tendon as the initial point of reference, measurements were made to the four subsequent sites. The humeral length was recorded by measuring the distance between the greater tuberosity and the lateral epicondyle as well as the tendon diameter at the articular surface. Results: The intraclass correlation coefficient was excellent across all measures. A total of nine cadavers were included. Mean age of patients was 66.33 years old, ranging from 52-82 years old. These were composed of five male and four female cadavers. The mean tendon length was 24.83mm ± 4.32 from the origin to the superior border of the bicipital groove, 73.50mm ± 6.96 to the Superior Border Pectoralis Major Tendon, 100.89mm ± 6.88 to the Musculotendinous Junction, and 111.11mm ± 7.45 to the Inferior Border Pectoralis Major Tendon. The mean tendon diameter at the articular origin was 6.44mm ± 1.76. Conclusion: This study provided measurement guidelines that could restore the natural length-tension relationship during biceps tenodesis using the interference screw technique in Filipinos. A simple method of restoring a normal length-tension relationship is by doing tenodesis close to the articular origin and creating a bone socket of approximately 25mm in depth, using the superior border of the bicipital groove as a landmark.