Faculty Bibliography

The rotator cable, an extension of the coracohumeral ligament, is a fibrous band-like structure that courses along the undersurface of the supraspinatus and infraspinatus tendons perpendicular to their tendon fibers. Originally described in the orthopaedic literature, the rotator cable likely plays an important role in the biomechanics of the intact and torn rotator cuff. Published data addressing the performance of MR imaging in the evaluation of the rotator cable is rather limited. The purpose of this exhibit is threefold: 1) to describe the normal gross anatomy, histology, as well as the MR imaging anatomy of the rotator cable, 2) to describe the role of imaging as it pertains to the cable's function in the biomechanics of the intact and torn rotator cuff, 3) to underscore the clinical significance of the cable in terms of classification and treatment of rotator cuff tears. Introduction to the most current knowledge on the origin, distribution, and insertions of the rotator cable using gross anatomy, histology, and MR imaging correlation will be presented. Emphasis will be placed on the MR appearance of the rotator cable in orthogonal imaging planes in both intact and torn rotator cuffs. The role of the rotator cable in the setting of rotator cuff pathology will be underscored using MRI, including its potential contributions to the geometric configuration of cuff tears, altered glenohumeral biomechanics, and fatty degeneration of the rotator cuff musculature. Lastly, a review of the clinical importance of the rotator cable will be provided focused on the effect of the cable's integrity in the management of rotator cuff tears

The extreme range of motion at the shoulder, high velocities and stresses, and repetitive nature of the throwing motion place the throwing athlete at risk for a wide range of pathologic entities. The treating orthopedist must fully understand the biomechanics of the throwing cycle and how it contributes to the potential injuries in the throwing shoulder during each phase of the throwing motion. The goal of orthopedic care and rehabilitation is to allow the throwing athlete to return symptom free to the preinjury level of competition.

PURPOSE: We have occasionally observed suture loosening in initial suture legs after final fixation of adjacent suture legs in the lateral row of rotator cuff repairs during arthroscopic rotator cuff repair with transosseous-equivalent suture-bridge constructs. We sought to determine how this occurred and what effects it had on tendon fixation stability. METHODS: Six pairs of fresh-frozen human shoulders were prepared with a simulated cuff defect. A suture-bridge repair was performed in each specimen with one of each pair randomized to one type of 'knotless' lateral-row screw-in anchor and the other of the pair to a knotless push-in type. The repairs were cyclically loaded with 100 N for 1,000 cycles. Suture leg tensions were measured during the repair and after cycling. Lateral tendon laxity was measured before and after cycling. A pilot study on the effect of suture tension on the tendon contact footprint was also performed. RESULTS: The initial suture legs did not show a decrease in tension after the second lateral-row anchor was secured. Tension of the suture legs after cycling showed that no one leg loosened more than another; however, they all loosened when compared with total suture tensions before cycling (0.1 to 1.0 mm, P = .008). There was no significant difference between suture tension changes for the 2 anchor types after cycling (P = .140). Although the lateral tendon laxity increased slightly (0.04 mm) after cycling, this was not significant (P = .245), nor was there a difference between anchor types. CONCLUSIONS: Suture loosening occurred after cycling these rotator cuff repairs, but this did not appear to affect lateral tendon laxity for the 2 lateral anchor types studied, although medial tendon movement was observed. CLINICAL RELEVANCE: Suture loosening after cycling the 2 transosseous-equivalent suture-bridge repairs studied could affect the area and pressure of tendon-bone contact

The pathology, assessment, and management of articular cartilage lesions of the hip and knee have been the subject of considerable attention in the recent orthopaedic literature. MRI has long been an important tool in the diagnosis and management of articular cartilage pathology, but detecting and interpreting early cartilaginous degeneration with this technology has been difficult. Biochemical-based MRI has been advocated to detect early cartilaginous degenerative changes and assess cartilage repair. Techniques such as T2 mapping, T1rho (ie, T1 in the rotating frame), sodium MRI, and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) take advantage of changes in the complex biochemical composition of articular cartilage and may help detect morphologic cartilaginous changes earlier than does conventional MRI. Although the newer modalities have been used primarily in the research setting, their ability to assess the microstructure of articular cartilage may eventually enhance the diagnosis and management of osteoarthritis

Anterior cruciate ligament (ACL) and meniscal injuries are common in both athletes and the general population. Such injuries may lead to early-onset post-traumatic osteoarthritis (OA) in 50% to 60% of patients, regardless of whether patients had reconstruction performed. In younger patients, intra-articular (IA) injection of hyaluronic acid (HA) may be useful for improving short-term outcomes and possibly slowing or arresting the progression of OA. Hyaluronic acid has anti-inflammatory, anabolic, and chondroprotective effects, which have been demonstrated in in vitro and animal models of meniscal and ACL injury. Results from several clinical trials and patient series have demonstrated the benefit of IA HA injection in younger patients with acute knee damage, including symptomatic meniscal tears and isolated ACL injury with chondral injury, although evidence for this is less extensive than the large database supporting the use of IA HA injection in older patients with knee OA. Administration of HA has been shown to improve outcomes in patients undergoing knee arthroscopy, and IA HA also has direct antinociceptive effects that may contribute to its benefit in patients with patellofemoral pain. However, the use of IA HA in patients with ACL injury or early OA has been evaluated in only a few studies. Thus, there is a need for larger-scale randomized controlled trials with longer durations of follow-up to provide more definitive evaluation of the efficacy and safety of IA HA in these patients. Such studies provide an opportunity to further elucidate the benefits of IA HA in younger patients with knee damage and may result in appropriate expansion of use in this large population, which has a substantial need for new treatment alternatives

The use of bioabsorbable cross-pin transcondylar fixation has remained a viable option for femoral fixation in anterior cruciate ligament reconstruction. Although numerous biomechanical studies have demonstrated high fixation strength and minimal slippage with use of this method of fixation, there have been increasing reports of a variety of clinical complications associated with these implants. We reviewed the literature for all complications associated with the Bio-TransFix implant and present a case report of a patient status after ACL reconstruction using Bio-TransFix cross-pin femoral fixation with iliotibial band friction syndrome from a broken cross-pin four month post-operatively.

OBJECTIVE: The purpose of this article is to review imaging of the rotator interval, an anatomically complex region in the shoulder that plays an important role in the normal function of the shoulder joint. The rotator interval can be difficult to evaluate by imaging, and it is not routinely evaluated arthroscopically unless the clinical examination or imaging findings suggest an abnormality of the rotator interval. Rotator interval pathology is implicated in glenohumeral instability, biceps instability and adhesive capsulitis-entities which remain a challenge to diagnose and treat. CONCLUSION: Imaging can play an important role in increasing suspicion for injury to the rotator interval so that this region can be evaluated and appropriate treatment can be initiated