Copeland EAS hemi-resurfacing arthroplasty for rotator cuff tear arthropathy: preliminary results.

Hemiarthroplasty is a common form of treatment for rotator cuff tear arthropathy. Clinical outcomes of the bone-sparing Copeland Extended Articular Surface (EAS) hemi-resurfacing arthroplasty for rotator cuff tear arthropathy have not been reported in the literature. This article presents the authors' preliminary results in this study. Six patients treated with this prosthesis were retrospectively reviewed and the preoperative and postoperative scores for range of motion and outcomes as assessed by the disabilities of the arm, shoulder, and hand (DASH) questionnaire and visual analog scale for pain were compared. Significant improvements were found in function, with DASH scores decreasing from an average of 55 to 22, pain improving from 8.83 to 4.5, and external rotation improving from 49; to 67;. Five of the six patients were satisfied with the outcome of the procedure. This level IV therapeutic study concluded that the bone-sparing Copeland EAS hemi-resurfacing arthroplasty is a viable alternative to stemmed hemiarthroplasty for the treatment of rotator cuff tear arthropathy in younger, more active patients in whom future revision is a likely possibility.

Evaluation of the accuracy of three CT-free surgical navigation systems in total knee arthroplasty (TKA) using a coordinate measuring machine.

Previous studies have shown that the accuracy of computer-assisted surgery (CAS) via computed tomography (CT) free systems is useful when applied in the clinical realm. However, few studies have compared CAS systems to the current gold standard, manually applied measuring guides. Thirty total knee arthroplasties (TKA) were performed on artificial Sawbones knees using three different navigational systems. The TKAs were performed by a fellowship-trained joint reconstruction surgeon as well as a third- and a fourth-year orthopedic resident to assess differences in performance with regard to surgical experience. Using a two-way multivariate analysis of variance (MANOVA), no statistical differences were found in the accuracy of each of the three CAS navigational systems. Similarly, no differences were found between the accuracy of CAS systems and the gold standard measuring method. No differences in performance were found between the orthopedic residents and the fellowship-trained surgeon, suggesting a relatively small learning curve and usability. Definitive assessment of the clinical efficacy should be further assessed in a cadaveric study or, ideally, by way of a randomized clinical trial.

An in vitro analysis of ligament reconstruction or extension osteotomy on trapeziometacarpal joint stability and contact area.

PURPOSE: Painful instability of the minimally osteoarthritic thumb carpometacarpal (CMC) joint can be treated successfully by either ligament reconstruction or metacarpal extension osteotomy. The purpose of this study was to measure the laxity of cadaveric thumb CMC joints and to determine the influence of ligament reconstruction and metacarpal osteotomy on joint laxity and contact area. METHODS: The baseline laxity of CMC joints from 25 fresh-frozen human cadaveric specimens (average age, 42 y; range, 18-55 y) was measured in the position of lateral pinch on a custom-designed CMC joint laxity tester. Joint laxity was measured again after 2 surgical simulations consisting of either a metacarpal extension osteotomy (at 10 degrees and 15 degrees) or a simulated Eaton-Littler ligament reconstruction (including total, volar, and dorsal ligament reconstructions relative to the plane of the thumbnail). Contact area between the thumb metacarpal and trapezium during testing was determined using stereophotogrammetry. RESULTS: The 15 degrees extension osteotomy significantly reduced CMC joint laxity in the radial-ulnar, dorsal-volar, pronation-supination, and distraction directions in the position of lateral pinch. The 10 degrees osteotomy reduced laxity only in the dorsal-volar direction. The total ligament reconstruction significantly reduced joint laxity in the radial-ulnar, dorsal-volar, and pronation-supination directions. The dorsal ligament reconstruction reduced laxity in the dorsal-volar direction only; the volar ligament reconstruction reduced laxity in both dorsovolar and radioulnar directions. The 10 degrees and 15 degrees osteotomies produced a dorsal shift of the weighted centroid of contact on the metacarpal and trapezium, whereas the ligament reconstruction did not produce such an effect. CONCLUSIONS: In the position of lateral pinch the 15 degrees osteotomy and total ligament reconstruction significantly reduced laxity of the thumb CMC joint in all directions tested. The isolated dorsal or volar ligament reconstructions both reduced dorsal-volar laxity. Metacarpal extension osteotomy may stabilize the thumb CMC joint in lateral pinch to a degree similar to that of a standard ligament reconstruction.

Simulated extension osteotomy of the thumb metacarpal reduces carpometacarpal joint laxity in lateral pinch.

PURPOSE: To assess the effect of an extension osteotomy of the thumb metacarpal on thumb carpometacarpal (CMC) joint laxity with respect to the lateral pinch position. METHODS: Seven fresh-frozen specimens were dissected. The metacarpal, trapezium, and trapezoid were removed en bloc and rigidly fixed proximally and distally. The laxity of each specimen was measured by cyclically loading the CMC joint in a custom-built laxity testing device designed to allow relative movement of the trapezium and first metacarpal in 4 directions. The position of the CMC joint in lateral pinch was used as the baseline joint position. An extension osteotomy then was simulated by flexing the metacarpal base 30 degrees, thus placing the joint in the relationship it would assume if an extension osteotomy was performed and the specimen was positioned in lateral pinch. Laxity measurements then were repeated. RESULTS: The simulated extension osteotomy reduced laxity in all directions tested: dorsal-volar (40% reduction), radial-ulnar (23% reduction), distraction (15% reduction), and pronation-supination (29% reduction). CONCLUSIONS: The beneficial clinical effects of a thumb metacarpal extension osteotomy may be partially due to reduced joint laxity in the position of lateral pinch.