Aims

The aim of this systematic review and meta-analysis was to gather epidemiological information on selected musculoskeletal injuries and to provide pooled injury-specific incidence rates.

Aims. The conventionally described mechanism of distal biceps tendon rupture (DBTR) is of a ‘considerable extension force suddenly applied to a resisting, actively flexed forearm’. This has been commonly paraphrased as an ‘eccentric contracture to a flexed elbow’. Both definitions have been frequently used in the literature with little objective analysis or citation. The aim of the present study was to use video footage of real time distal biceps ruptures to revisit and objectively define the mechanism of injury. Methods. An online search identified 61 videos reporting a DBTR. Videos were independently reviewed by three surgeons to assess forearm rotation, elbow flexion, shoulder position, and type of muscle contraction being exerted at the time of rupture. Prospective data on mechanism of injury and arm position was also collected concurrently for 22 consecutive patients diagnosed with an acute DBTR in order to corroborate the video analysis. Results. Four videos were excluded, leaving 57 for final analysis. Mechanisms of injury included deadlift, bicep curls, calisthenics, arm wrestling, heavy lifting, and boxing. In all, 98% of ruptures occurred with the arm in supination and 89% occurred at 0° to 10° of elbow flexion. Regarding muscle activity, 88% occurred during isometric contraction, 7% during eccentric contraction, and 5% during concentric contraction. Interobserver correlation scores were calculated as 0.66 to 0.89 using the free-marginal Fleiss Kappa tool. The prospectively collected patient data was consistent with the video analysis, with 82% of injuries occurring in supination and 95% in relative elbow extension. Conclusion. Contrary to the classically described injury mechanism, in this study the usual arm position during DBTR was forearm supination and elbow extension, and the muscle contraction was typically isometric. This was demonstrated for both video analysis and ‘real’ patients across a range of activities leading to rupture. Cite this article: Bone Jt Open 2022;3(10):826–831

The February 2014 Shoulder & Elbow Roundup³⁶⁰ looks at: whether arthroscopic acromioplasty is a cost-effective intervention; shockwave therapy in cuff tear; whether microfracture relieves short-term pain in cuff repair; the promising early results from L-PRF augmented cuff repairs; rehabilitation following cuff repair; supination strength following biceps tendon rupture; whether longer is better in humeral components; fatty degeneration in a rodent model; and the controversial acromioclavicular joint dislocation.