Hartzler, Robert U.

Background: Recurrent anterior shoulder instability may lead to capsuloligamentous and bony lesions of the glenoid and humerus. To date, there is no clear consensus on how to best measure anterior glenoid bone loss (GBL) in the setting of recurrent instability. The objective of this study, therefore, was to evaluate the accuracy and reliability of 7 different methods of measuring anterior GBL on three-dimensional models based on computed tomography. Methods: Eight levels of GBL in the anterior and anteroinferior directions were virtually generated in 14 three-dimensional healthy glenoid models. GBL was measured with 7 different methods: based on a height/width ratio (M1), based on surface area within a circle (M2 and M3), based on linear distance within a circle, (M4, M5, and M6), and based on a volume ratio (M7). For each method, the measurement accuracy was assessed by comparing the calculated value with the true amount of generated GBL. The measurement reliability was assessed by computing the score variance and intraclass correlation coefficient. Results: The most accurate (average measurement error of <2% and largest proportion with error <5%) and reliable (ICC >0.96) measurement methods for GBL were M2 (based on surface area) and M5 (based on the linear distance). The average measurement error for the other methods ranged between 3% and 11% for anterior GBL and between 2% and 9% for anteroinferior GBL. For anterior GBL, the measurement increased by an average of 0.5% for each 1% increase in circle radius, leading to an overestimation of GBL with a larger circle diameter Conclusion: The methods for calculating glenoid bone loss performed better for the more common direct anterior bone loss rather than the less common anteroinferior-directed bone loss. Both an area-based method (M2) and linear distance–based method (M5) resulted in accurate and reliable measurements of glenoid bone loss; however, the linear distance–based methods may be easier to perform clinically. The height-width ratio and volume methods were less accurate and reliable. Level of Evidence: Level IV ; case series; diagnostic studies. See Instructions for Authors for a complete description of levels of evidence.

Background The purpose was to evaluate the relationship of component size and position to postoperative range of motion following reverse shoulder arthroplasty. The hypothesis was that increased lateralization, larger glenospheres, and a decreased acromiohumeral distance would be associated with excellent postoperative range of motion. Methods A retrospective multicenter study was performed at a minimum of one year postoperatively on 160 patients who underwent primary reverse shoulder arthroplasty with a 135° humeral component. Outcomes were stratified based on postoperative forward flexion and external rotation into excellent ( n = 42), defined as forward flexion >140° and external rotation > 30°, or poor ( n = 36), defined as forward flexion <100° and external rotation < 15°. Radiographic measurements and component features were compared between the two groups. Results A larger glenosphere size was associated with an excellent outcome ( p = 0.009). A 2-mm posterior offset humeral cup ( p = 0.012) and an increased inferior glenosphere overhang (3.1 mm vs 1.4 mm; p = 0.002) were also associated with excellent outcomes. Humeral lateralization and distalization were not associated with an excellent outcome. Conclusion: Larger glenosphere size and inferior positioning as well as posterior humeral offset are associated with improved postoperative range of motion following reverse shoulder arthroplasty. Level of Evidence Level 3, retrospective comparative study.

Background: Polyethylene (PE) liner and femoral head exchange is commonly used to treat periprosthetic osteolysis associated with PE wear after total hip arthroplasty (THA). The purpose of our study was to determine long-term implant survivorship, risk factors for mechanical failure, clinical outcomes, and complications following PE liner and head exchange. Methods: We identified 116 hips in 110 patients treated with PE liner and head exchange from 1993 to 2004. There were 64 women (58%) in the series, the mean age at revision surgery was 58 years, and the mean follow-up was 11 years (range, 2 to 23 years). Radiographic review determined the location and size of osteolytic defects before the revision surgery. Implant survivorship was determined using Kaplan-Meier survival analysis. Cox regression analysis was used to determine factors that were predictive of failure. Results: Implant survivorship free of repeat revision for any cause was 91% (95% confidence interval [CI] = 86% to 96%) at 5 years, 81% (95% CI = 74% to 90%) at 10 years, and 69% (95% CI = 55% to 84%) at 15 years. Reasons for repeat revision included aseptic acetabular loosening in 5 hips (4%) and subsequent wear of conventional PE with osteolysis in 5 hips (4%). No patient who underwent revision with highly cross-linked PE subsequently had a repeat revision due to wear. The absolute risk of acetabular component loosening was 23% for patients with osteolysis in 3 zones, 40% for those with osteolysis involving more than half the cup circumference, and 21% for those with osteolytic defects of >600 mm 2 . The mean Harris hip score improved from 77 before the PE liner and head exchange to 87 after it (p < 0.001). The most common complication was dislocation, which occurred in 19 hips (16%). Conclusions: PE liner and head exchange provides acceptable long-term implant survivorship with good clinical outcomes. Complications are not uncommon, and steps should be taken to mitigate hip instability. Acetabular revision may be considered when in situ components have a poor track record or are malpositioned, or when preoperative radiographs demonstrate large osteolytic defects threatening cup fixation. Use of highly cross-linked PE at revision was protective against subsequent PE wear and osteolysis, although this did not reach significance. Level of Evidence: Therapeutic Level IV . See Instructions for Authors for a complete description of levels of evidence.

Aims Animal models have been developed that allow simulation of post-traumatic joint contracture. One such model involves contracture-forming surgery followed by surgical capsular release. This model allows testing of antifibrotic agents, such as rosiglitazone. Methods A total of 20 rabbits underwent contracture-forming surgery. Eight weeks later, the animals underwent a surgical capsular release. Ten animals received rosiglitazone (intramuscular initially, then orally). The animals were sacrificed following 16 weeks of free cage mobilisation. The joints were tested biomechanically, and the posterior capsule was assessed histologically and via genetic microarray analysis. Results There was no significant difference in post-traumatic contracture between the rosiglitazone and control groups (33° (standard deviation (sd) 11) vs 37° (sd14), respectively; p = 0.4). There was no difference in number or percentage of myofibroblasts. Importantly, there were ten genes and 17 pathways that were significantly modulated by rosiglitazone in the posterior capsule. Discussion Rosiglitazone significantly altered the genetic expression of the posterior capsular tissue in a rabbit model, with ten genes and 17 pathways demonstrating significant modulation. However, there was no significant effect on biomechanical or histological properties. Cite this article: M. P. Abdel. Effectiveness of rosiglitazone in reducing flexion contracture in a rabbit model of arthrofibrosis with surgical capsular release: A biomechanical, histological, and genetic analysis. Bone Joint Res 2016;5:11–17. doi: 10.1302/2046-3758.51.2000593

Surgical treatment has been advocated for ischial tuberosity avulsion fractures in athletes. This article presents the case of an elite rower with a large avulsion fracture involving the entire inferior obturator ring with a novel technique for open reduction using a limited Kocher-Langenbeck approach and percutaneous fixation using posterior column lag screws. The fracture healed anatomically, and at 1 year follow-up the patient had full range of motion, normal gait and had returned to high-level sporting activities.

ABSTRACTAnimal models of joint contracture may be used to elucidate the mechanisms of arthrofibrosis. Patients with joint contracture commonly undergo surgical capsular release. Previous animal models of joint contracture do not simulate this aspect of arthrofibrosis. We hypothesize that a surgical capsular release will decrease the severity of arthrofibrosis in this rabbit model. A capsular contracture was surgically created in 20 skeletally mature rabbits. Eight weeks later, ten rabbits underwent capsular release, which consisted of elevation of the posterior capsule through a lateral incision and manipulation under anesthesia. Ten rabbits had a sham incision, without release (control group). Immediately after release or sham surgery, extension loss (calculated by subtracting the knee extension angle (degrees) of the operative limb from the nonoperative, contralateral limb) was measured using fluoroscopy. All animals were sacrificed following 16 weeks of postoperative free cage activity. At sacrifice, joint contracture was measured using a custom, calibrated device. The histology of the posterior joint capsule was assessed at sacrifice. All animals survived both operations without complications. Immediately after surgical release or sham surgery, the average extension loss was 129.2 ± 10.7° in the control group versus 29.6 ± 8.2° in the capsular release group (p = 0.0002). Following 16 weeks of remobilization, the average extension loss of the control and capsular release animals were 49.0 ± 12.7° and 36.5 ± 14.2°, respectively (p = 0.035). There were no histological differences between the two groups. In this animal model, a surgical capsular release decreased the extension loss (flexion contracture) immediately after surgery, as well as following sixteen weeks of remobilization. There were no histological changes detected in the posterior joint capsule. © 2013 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:1529–1532, 2013