Biomechanical Comparison of Two Surgical Repair Techniques of the Distal Biceps Tendon.

Purpose: This study aimed to characterize the relationship between the distal biceps tendon force and the supination and flexion rotations during the initiation phase and to compare the functional efficiency of anatomic versus nonanatomic repairs. Methods: Seven matched pairs of fresh-frozen cadaver arms were dissected to expose the humerus and elbow while preserving the biceps brachii, elbow joint capsule, and distal radioulnar soft tissue complex. For each pair, the distal biceps tendon was severed with a scalpel and then repaired with bone tunnels placed at either the anterior (anatomic) or the posterior (nonanatomic) aspect of the bicipital tuberosity on the proximal radius. A supination test with 90° of elbow flexion and an unconstrained flexion test were conducted on a customized loading frame. The biceps tension was applied incrementally at 200 g per step, whereas the radius rotation was tracked with a 3-dimensional motion analysis system. The tendon force needed to produce a degree of supination or flexion was derived as the regression slope of the tendon force-radial rotation plots. A two-tailed paired t test was performed to compare the difference between the anatomic repair and the nonanatomic repair cadavers. Results: Significantly greater tendon force was required to initiate the first 10° of supination with the elbow in flexion for the nonanatomic group compared with the anatomic group (1.04 ± 0.44 N/degree vs 0.68 ± 0.17 N/degree, P = .02). The average nonanatomic to anatomic ratio was 149% ± 38%. No difference existed between the two groups in the mean tendon force needed to produce the degree of flexion. Conclusions: Our results show that anatomic repair is more efficient in producing supination than nonanatomic repair, but only when the elbow is in 90° of flexion. When the elbow joint is not constrained, the nonanatomic supination efficiency improved, and the difference between the techniques was not significant. Clinical relevance: The present study added to the body of evidence in comparing anatomic versus nonanatomic repair of the distal biceps tendon and serves as a foundation for future biomechanical and clinical studies in this topic. Given no difference when the elbow joint was not constrained, one could argue that surgeon comfort and preference could guide which technique to use when addressing the distal biceps tendon tears. More studies will be needed to clearly define whether there will be a clinical difference between the two techniques.

Is the radial groove a myth? Is the radial nerve in direct contact with the posterior humerus?

BACKGROUND: The radial groove is known as a sulcus on the posterior humerus and protects the radial nerve from adjacent muscle and soft tissue. In the literature, there exists heterogeneity regarding the presence of an actual radial groove and the radial nerve's interaction with the periosteum of the humerus. This study aimed to determine if there is a real radial groove, "sulcus," and define the relationship between the radial nerve and the periosteum of the posterior humerus. METHODS: Eighteen fresh-frozen cadaveric specimens were dissected using a posterior triceps splitting approach. The radial nerve's interaction with the periosteum of the humerus was determined. The presence of a visible and palpable radial groove was also examined. RESULTS: In 56% of specimens, the radial nerve was directly seated over the periosteum of the posterior humerus (direct contact between the nerve and bone). In comparison, 44% of specimens had a layer of the medial head of the triceps brachii muscle fibers interposition between the nerve and bone. 89% of specimens had no visible or palpable radial groove. In 11% of specimens, there was mild palpable depression. CONCLUSION: This study shows that the radial groove may not exist and is probably not a true anatomical structure. In addition, the nerve is in direct contact with the posterior periosteum of the humerus in most specimens. These anatomic relationships and findings add to the anatomical understanding of the radial nerve, which helps during operative approaches and fixation of the humerus.

TightRope Versus Biocomposite Interference Screw for Fixation in Allograft ACL Reconstruction: Prospective Evaluation of Osseous Integration and Patient Outcomes.

BACKGROUND: Anterior cruciate ligament (ACL) reconstruction is a commonly performed procedure with many options regarding graft choice and graft fixation. The purpose of this study was to compare suspensory and aperture fixation in terms of femoral osseous integration of the bone block after ACL reconstruction with an Achilles tendon allograft. METHODS: After institutional review board approval and patient consent were obtained, 37 patients underwent ACL reconstruction with an Achilles tendon allograft. The patients were randomized according to the graft femoral fixation technique, which was with either a suspensory device (Arthrex TightRope) or aperture fixation by a biocomposite interference screw (Arthrex BioComposite Interference Screw or DePuy Mitek MILAGRO Interference Screw). Tibial fixation, performed with a biocomposite screw and knotless anchor, was identical in all patients. All patients underwent a computed tomography (CT) scan at 6 months to evaluate bone block incorporation of the femoral graft within the femoral tunnel, which was the study's primary outcome. Secondary outcome measures included a postoperative visual analogue scale (VAS) pain score, range-of-motion measures, and International Knee Documentation Committee scores. Demographic data were collected. RESULTS: Thirty-three patients (89%) completed the study's 6-month follow-up, at which time the femoral ossification score was significantly greater in the aperture fixation group (p = 0.025). There was no substantial difference between the 2 groups with regard to any other outcome measure. CONCLUSIONS: Performing Achilles tendon allograft ACL reconstruction with femoral aperture fixation results in greater femoral bone block incorporation at 6 months postoperatively compared with what is seen after suspensory fixation. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Efficacy of a Virtual Arthroscopic Simulator for Orthopaedic Surgery Residents by Year in Training.

BACKGROUND: Virtual reality arthroscopic simulators are an attractive option for resident training and are increasingly used across training programs. However, no study has analyzed the utility of simulators for trainees based on their level of training/postgraduate year (PGY). PURPOSE/HYPOTHESIS: The primary aim of this study was to determine the utility of the ArthroS arthroscopic simulator for orthopaedic trainees based on their level of training. We hypothesized that residents at all levels would show similar improvements in performance after completion of the training modules. STUDY DESIGN: Descriptive laboratory study. METHODS: Eighteen orthopaedic surgery residents performed diagnostic knee and shoulder tasks on the ArthroS simulator. Participants completed a series of training modules and then repeated the diagnostic tasks. Correlation coefficients (r 2) were calculated for improvements in the mean composite score (based on the Imperial Global Arthroscopy Rating Scale [IGARS]) as a function of PGY. RESULTS: The mean improvement in the composite score for participants as a whole was 11.2 ± 10.0 points (P = .0003) for the knee simulator and 14.9 ± 10.9 points (P = .0352) for the shoulder simulator. When broken down by PGY, all groups showed improvement, with greater improvements seen for junior-level residents in the knee simulator and greater improvements seen for senior-level residents in the shoulder simulator. Analysis of variance for the score improvement variable among the different PGY groups yielded an f value of 1.640 (P = .2258) for the knee simulator data and an f value of 0.2292 (P = .917) for the shoulder simulator data. The correlation coefficient (r 2) was -0.866 for the knee score improvement and 0.887 for the shoulder score improvement. CONCLUSION: Residents training on a virtual arthroscopic simulator made significant improvements in both knee and shoulder arthroscopic surgery skills. CLINICAL RELEVANCE: The current study adds to mounting evidence supporting virtual arthroscopic simulator-based training for orthopaedic residents. Most significantly, this study also provides a baseline for evidence-based targeted use of arthroscopic simulators based on resident training level.

Management of distal humeral coronal shear fractures.

Coronal shear fractures of the distal humerus are rare, complex fractures that can be technically challenging to manage. They usually result from a low-energy fall and direct compression of the distal humerus by the radial head in a hyper-extended or semi-flexed elbow or from spontaneous reduction of a posterolateral subluxation or dislocation. Due to the small number of soft tissue attachments at this site, almost all of these fractures are displaced. The incidence of distal humeral coronal shear fractures is higher among women because of the higher rate of osteoporosis in women and the difference in carrying angle between men and women. Distal humeral coronal shear fractures may occur in isolation, may be part of a complex elbow injury, or may be associated with injuries proximal or distal to the elbow. An associated lateral collateral ligament injury is seen in up to 40% and an associated radial head fracture is seen in up to 30% of these fractures. Given the complex nature of distal humeral coronal shear fractures, there is preference for operative management. Operative fixation leads to stable anatomic reduction, restores articular congruity, and allows initiation of early range-of-motion movements in the majority of cases. Several surgical exposure and fixation techniques are available to reconstruct the articular surface following distal humeral coronal shear fractures. The lateral extensile approach and fixation with countersunk headless compression screws placed in an anterior-to-posterior fashion are commonly used. We have found a two-incision approach (direct anterior and lateral) that results in less soft tissue dissection and better outcomes than the lateral extensile approach in our experience. Stiffness, pain, articular incongruity, arthritis, and ulnohumeral instability may result if reduction is non-anatomic or if fixation fails.