Is the Internal Rotation Lag Sign a Sensitive Test for Detecting Hip Abductor Tendon Ruptures after Total Hip Arthroplasty?

INTRODUCTION: Total hip arthroplasty (THA) is one of the most frequently performed procedures in orthopaedics and weakness of external rotators is often recognized thereafter. However, the etiology of lateral hip pain is multifaceted. For the diagnosis of abductor tendon rupture, magnetic resonance imaging (MRI) is the gold standard. As not every patient can be subjected to MRI, a clinical diagnostic test for easy detection of lesions of the abductor tendon is missing. Here, we present the internal rotation lack sign indicating abductor tendon pathology. METHODS: The patient is placed in lateral position on a stretcher with hips and knees in neutral position. The knee is flexed to 45° and the hip passively abducted and elevated by the investigator. With the foot passively abducted, the patient is then asked to bring his knee in direction to the examination table. This motion is also tested passively. The test is regarded positive, if no internal rotation is possible and/or if this is painful. If groin pain is elicited during either of the exercises, the test is also rated positive. RESULTS: We evaluated this test in 20 patients clinically and by magnetic resonance imaging (MRI). All patients demonstrated a positive internal rotation lag sign. Twelve of them lag of internal rotation and evidence of anterior abductor tendon rupture on MRI, 8 with lag of internal rotation and no evidence of abductor tendon rupture. CONCLUSION: The new clinical diagnostic sign presented here may improve the diagnosis of abductor tendon rupture in the future.Level of Evidence: Diagnostic study, level I

Tuberosity union in patients with proximal humerus fractures treated with reverse shoulder arthroplasty: a technical note and exploratory analysis

PURPOSE: The use of reverse shoulder arthroplasty (RSA) to treat complex humerus fractures is increasing, especially in older, osteoporotic patients. Refixation and tuberosity healing are needed to achieve an optimal range of motion (ROM), external rotation, active forward elevation, and patient satisfaction. Proper healing has been reported, however, in only 40-84% of cases. Our study's aim was to describe a simple, reproducible fixation technique designed to improve tuberosity healing. METHODS: We included 30 patients with acute proximal humerus fractures undergoing RSA (Global Unite Reverse Fracture, DePuy Synthes, Warsaw, IN, USA) with tuberosity reattachment. The humerus stem was cemented in 24 cases. A standardized suture technique with two fiber tapes was used to reattach tuberosities. Clinical and radiological parameters, which were collected one year post-operatively, included ROM, pain level, Constant scores, subjective shoulder value (SSV), and tuberosity healing. RESULTS: The mean age of the patients was 79.3 years (± 7; range 65-92), and the tuberosity healing rate was 90.0% (27 of 30). Two patients showed migration (one nonunion, one malunion), and another had complete resorption after an initial period of proper healing. Radiolucent lines around the humerus stem occurred in one case, and three patients had scapular notching. The mean SSV was 86% (± 11; range 60-100), the Constant score was 72 (± 10.3; range 48-92), the active forward flexion was 140° (± 14.3; range 115-165), and external rotation was 23° (± 16.5; range 0-50). CONCLUSIONS: This reattachment technique, which is simple and reproducible, achieved a higher tuberosity healing rate than previously published rates

Light-Responsive Block Copolymers

Stimuli-responsive polymers are the subject of intense research because they are able to show responses to various environmental changes. Among those stimuli, light has attracted much attention since it can be localized in time and space and it can also be triggered from outside of the system. In this paper, we review light-responsive block copolymers (LRBCs) that combine characteristic features of block copolymers, e. g., self-assembly behavior, and light-responsive systems. The different photo-responsive moieties that have been incorporated so far in block copolymers as well as the proposed applications are discussed