QUANTIFICATION OF THE DYNAMIC GLENOHUMERAL STABILITY PROVIDED BY THE ROTATOR CUFF MUSCLES IN THE LATE COCKING PHASE OF THROWING

The purpose of this study was to investigate quantitatively the dynamic glenohumeral stability provided by the rotator cuff muscles in the late-cocking phase of throwing. Using ten cadaveric shoulders, a new biomechanical parameter (dynamic stability index) was calculated considering compressive and shear forces to the glenoid provided by each cuff muscle. The rotator cuff muscles provided the joint with significant dynamic stability in the late cocking. However, the dynamic stability provided by the cuff muscles with the arm in coronal plane significantly decreased when compared with that in the scapular plane. Rehabilitation of the throwing athletes should emphasize strengthening of the external and internal rotators. Moving the arm into the coronal plane in the late cocking phase should be avoided by a specific strengthening program to prevent further anatomic damage to the static stabilizers

A hinged external fixator for complex elbow dislocations: A multicenter prospective cohort study

Background: Elbow dislocations can be classified as simple or complex. Simple dislocations are characterized by the absence of fractures, while complex dislocations are associated with fractures of the radial head, olecranon, or coronoid process. The majority of patients with these complex dislocations are treated with open reduction and internal fixation (ORIF), or arthroplasty in case of a non-reconstructable radial head fracture. If the elbow joint remains unstable after fracture fixation, a hinged elbow fixator can be applied. The fixator provides stability to the elbow joint, and allows for early mobilization. The latter may be important for preventing stiffness of the joint. The aim of this study is to determine the effect of early mobilization with a hinged external elbow fixator on clinical outcome in patients with complex elbow dislocations with residual instability following fracture fixation. Methods/Design. The design of the study will be a multicenter prospective cohort study of 30 patients who have sustained a complex elbow dislocation and are treated with a hinged elbow fixator following fracture fixation because of residual instability. Early active motion exercises within the limits of pain will be started immediately after surgery under supervision of a physical therapist. Outcome will be evaluated at regular intervals over the subsequent 12 months. The primary outcome is the Quick Disabilities of the Arm, Shoulder, and Hand score. The secondary outcome measures are the Mayo Elbow Performance Index, Oxford Elbow Score, pain level at both sides, range of motion of the elbow joint at both sides, radiographic healing of the fractures and formation of periarticular ossifications, rate of secondary interventions and complications, and health-related quality of life (Short-Form 36). Discussion. The outcome of this study will yield quantitative data on the functional outcome in patients with a complex elbow dislocation and who are treated with ORIF and additional stabilization with a hinged elbow fixator. Trial Registration. The trial is registered at the Netherlands Trial Register (NTR1996)

Radiocapitellar prosthetic arthroplasty: a report of 6 cases and review of the literature

Radiocapitellar prosthetic arthroplasty has recently been introduced to treat isolated degenerative arthritis of the radiocapitellar joint. Although this procedure is conceptually attractive and sound in situations in which radial head resection is inadequate, clinical experience is still limited. Its role in the treatment of isolated radiocapitellar degenerative arthritis in the ligamentous-intact elbow and forearm is not yet defined. Our purpose was to report the short-term results of 6 patients who were treated by radiocapitellar prosthetic arthroplasty for isolated radiocapitellar degenerative arthritis in the ligamentous-intact elbow, as well as to provide a review of the literature. Six patients were treated by radiocapitellar prosthetic arthroplasty for isolated degenerative arthritis of the radiocapitellar joint in the ligamentous-intact elbow. Their medical records were reviewed, and each patient was seen in the office. The mean follow-up period was 50 months (range, 30-64 months). The implant survival rate was 100%. Pain improved in all patients and all patients were satisfied. The mean flexion-extension arc increased from 98° (range, 75°-115°) to 110° (range, 105°-120°) (P = .17), and the mean pronation-supination arc increased from 133° (range, 75°-115°) to 143° (range, 120°-170°) (P = .34). The mean Disabilities of the Arm, Shoulder and Hand score was 24.3 (range, 6.7-52.5). According to the Mayo Elbow Performance Score, there were 3 excellent and 3 good results. The short-term follow-up results of radiocapitellar prosthetic arthroplasty for isolated radiocapitellar degenerative arthritis in the ligamentous-intact elbow and forearm seem favorable. Level IV, case series, treatment stud

Aseptic loosening rate of the humeral stem in the Coonrad-Morrey total elbow arthroplasty. Does size matter?

BACKGROUND Aseptic implant loosening is one of the most common complications leading to revision surgery in total elbow arthroplasty. Different humeral stem lengths are available with varying designs. In general, the decision of which stem length to use depends on the surgical diagnosis or simply the surgeon preference. Often, the longer stem is used for post-traumatic or revision cases while for rheumatoid patients the shorter stem is preferred. There are no data in the literature to favor one humeral stem size over the other according to the diagnosis. METHODS We analyzed the total elbow joint database of the Coonrad-Morrey design at our institution for aseptic loosening leading to revision and compared the revision rate and the survival of the 4- and 6-inch humeral stems. RESULTS Overall, revision for aseptic humeral loosening is infrequent and occurred in only 16 of 711 total elbow arthroplasties during a mean follow-up of 88 months. There was no significant difference in the revision rate between the 2 stem lengths (1.9% for the 4-inch stems and 2.6% for the 6-inch stem). CONCLUSION Revision rate was correlated to the surgical diagnosis and was significantly higher for post-traumatic patients than for rheumatoid patients (5.1% vs 0.66%, P < .001). Of interest, and possibly not surprising, the mean time to revision was shorter for the 4-inch stems than it was for the 6-inch stems (37 vs 95 months, P = .034)