Faculty Bibliography

BACKGROUND: To date, repair of the lacertus in distal biceps tendon ruptures, recommended by some, has not been evaluated. The goal of these biomechanical experiments was to evaluate the degree to which its repair increases the strength of a distal biceps tendon repair. HYPOTHESIS: An intact or repaired lacertus fibrosus will increase the strength of a distal biceps tendon repair. STUDY DESIGN: Controlled laboratory study. METHODS: Four matched pairs of fresh-frozen human cadaveric upper extremities were prepared by isolating the lacertus fibrosus and the distal biceps tendon. The extremity was placed in a custom-built rig with the distal biceps brachii clamped and affixed to a stepper motor assembly. The distal biceps tendon was sharply removed directly from the radial tuberosity and repaired through a bony tunnel in all specimens. One side of each pair was randomized to also receive repair of the lacertus. The specimens were pulled at a constant rate until failure. RESULTS: The mean failure strength, defined as maximal strength to 15 mm of displacement, was higher in specimens with a repaired lacertus (250.2 N vs 158.2 N; P =.012), as was mean maximum strength (256.8 N v. 164.5 N; P =.0058). Mean stiffness was not significantly different (16.36 N/mm vs 13.8 N/mm; P =.58). All specimens failed due to fracture at the bony bridge. CONCLUSION: Repair of the lacertus strengthened distal biceps tendon repair in a controlled laboratory setting. CLINICAL RELEVANCE: Repair of the lacertus fibrosus as an adjunct to distal biceps tendon repair strengthens the repair in the laboratory setting. Clinical testing is needed to verify that this increased strength improves clinical results. Surgeons should be cautioned to protect the underlying neurovascular structures during repair of the lacertus fibrosus and to avoid an overly tight repair

Posterior cruciate ligament injuries occur much less frequently than anterior cruciate ligament injuries. We review the important physical examination and radiographic findings, as well as provide the indications for nonoperative and operative treatment

The purpose of this study was to evaluate any differences in the accuracy of knee MRI interpretation between radiology and orthopaedic surgery residents as well as to evaluate differences in quality of interpretation relative to resident training level. In this study, 20 MRI scans demonstrating specific pathology of the knee were identified. From one institution, two radiology residents and two orthopaedic surgery residents of each postgraduate year (PGY) of training (2 to 5) were recruited. Each resident was asked to interpret all the studies and choose up to 16 diagnoses for each scan from the list provided. Orthopaedic surgery residents showed improvement in overall accuracy and specificity with each year of additional training. Level of training did not correspond with increased sensitivity in the orthopaedic residents tested. Radiology residents did not demonstrate a consistent trend toward improved accuracy, sensitivity, or specificity with additional years of training. The only statistically significant differences in specificity observed between the two groups were seen in the readings of ACL tears, lateral femoral condyle chondromalacia, and chondromalacia patella. This study found that the accuracy of knee MRI interpretations between radiology and orthopaedic surgery residents did not demonstrate any differences. Level of training had no effect on the interpretation of the MRIs by radiology residents. Orthopaedic surgery residents did show an improvement with each year of additional training

This study was performed to determine if a meniscal al- lograft with attached bone plug and suture offers superior ixation when compared to allograft afixed with suture alone through a bony tunnel. Seven pairs of human cadaver proximal tibia specimens were obtained. The specimens were then randomly assigned to either Group 1 (suture alone) or Group 2 (bone plug plus suture). All Group 1 specimens had the meniscus detached at the bony insertion of the anterior and posterior horns, with two No. 2 Ethibond sutures placed at the posterior root insertion. All Group 2 specimens had a posterior horn with a bone plug and two No. 2 Ethibond sutures. Both groups had their respective sutures passed through a 7 mm tibial tunnel and secured over a screw and post on the proximal tibia. The specimens were then loaded to failure. The mean failure load for Group 1 was 111.8 N (SD: 21 N) and for Group 2 was 112 N (SD: 32 N). Based on the Wilcoxon Rank-Sum analysis, the two groups were not signiicantly different. This study demonstrated no difference in the mean pullout strength of medial meniscal allograft posterior horn ixation between the two groups. This biome- chanical cadaveric study demonstrated that it may not be necessary to use an attached bone plug for medial meniscal transplant ixation, as using suture alone will sufice. The choice of using suture alone for the posterior horn meniscal attachment eases the technique of surgery when compared to using a bone plug plus suture

The posterolateral region of the knee is an anatomically complex area that plays an important role in the stabilization of the knee relative to specific force vectors at low angles of knee flexion. A renewed interest in this region and advanced biomechanical studies have brought additional understanding of both the anatomy and the function of posterolateral structures in knee stabilization and kinematics. Through sectioning and loading studies, the posterolateral corner has been shown to play a role in the prevention of varus angulation, external rotation, and posterior translation. The potential for long-term disability from these injuries may be related to increased articular pressure and chondral degeneration. The failure of the reconstruction of cruciate ligaments may be due to unrecognized or untreated posterolateral corner injuries. Various methods of repair and reconstruction have been described and new research is yielding superior results from reconstruction of this region

Articular cartilage defects are common and play a significant role in degenerative joint disease. Cartilage is unable to regenerate, secondary to an inherent lack of vascular supply, thus, various techniques have been described in an attempt to treat and potentially restore these defects. Treatment decisions should be based on appropriate evaluation and classification of the pathology. Only then can the surgeon choose to perform a repair or a restoration of the articular surface. Current literature and techniques for the treatment of articular cartilage defects are reviewed, with an algorithm developed for the management of articular cartilage defects by orthopaedic surgeons.

PURPOSE: To retrospectively assess magnetic resonance (MR) imaging features of radial tunnel syndrome. MATERIALS AND METHODS: Institutional review board approval was obtained, and informed consent was waived for the retrospective HIPAA-compliant study. MR images of 10 asymptomatic volunteers (six men, four women; mean age, 30 years) and 25 patients (11 men, 14 women; mean age, 49 years) clinically suspected of having radial tunnel syndrome were reviewed for morphologic and signal intensity alterations of the posterior interosseous nerve and adjacent soft-tissue structures. MR images of the asymptomatic volunteers were reviewed to establish the normal appearance of the radial tunnel. MR images of the symptomatic patients were evaluated for the following: signal intensity alteration and morphologic alteration of the posterior interosseous nerve; the presence of mass effect on the posterior interosseous nerve such as the presence of bursae, a thickened leading edge of the extensor carpi radialis brevis, or prominent radial recurrent vessels; signal intensity alteration within the depicted forearm musculature such as edema or atrophy; and signal intensity changes at the origin of the common extensor and common flexor tendons, which would suggest a diagnosis of epicondylitis. RESULTS: All images of volunteers demonstrated normal morphology and signal intensity within the posterior interosseous nerve and adjacent soft tissues. Two volunteers had borderline thickening of the leading edge of the extensor carpi radialis brevis. Thirteen patients (52%) had denervation edema or atrophy within muscles (supinator and extensors) innervated by the posterior interosseous nerve. One patient had isolated pronator teres edema. Seven (28%) patients had the following mass effects along the posterior interosseous nerve: thickened leading edge of the extensor carpi radialis brevis (n = 4), prominent radial recurrent vessels (n = 1), schwannoma (n = 1), or bicipitoradial bursa (n = 1). The rest of the patients had either normal MR imaging findings (n = 4) or lateral epicondylitis (n = 2). CONCLUSION: Muscle denervation edema or atrophy along the distribution of the posterior interosseous nerve is the most common MR finding in radial tunnel syndrome

Tibial fixation of soft-tissue grafts is a weak link in anterior cruciate ligament reconstruction. Previous studies have examined varying interference screw lengths, screw types and tunnel sizes as means to improve graft fixation. We hypothesized that increasing interference screw diameter would significantly increase the maximum load to failure of the graft and decrease the graft's initial slippage. Seventy tibialis anterior and tibialis posterior tendons were divided, looped, trimmed, and sutured to simulate 4-strand hamstring grafts. These grafts were then inserted into composite bone blocks having pre-drilled 8 mm holes and fixed with 8 mm, 9 mm, 10 mm, 11 mm, or 12 mm interference screws. Fourteen grafts were tested for each screw size. The graft was first cyclically loaded from 50 N to 250 N at 0.3 Hz for 100 cycles to measure graft slippage. The graft was then tested to failure at 0.5 mm/sec to determine the maximum load to failure and mode of failure. Graft slippage was not affected by screw diameter. Maximum load to failure increased with increasing screw diameter up to 11 mm; 11 mm screw fixation was 20% stronger than 8 mm screw fixation. In this model, no increase in graft fixation was seen in by increasing interference screw diameter beyond 3 mm of the tunnel diameter