Jonathan D. Barlow

Myofibroblast cells are preferentially expressed early in a rabbit model of joint contracture

Studies have demonstrated increased myofibroblasts in contractures. However, the timeline is largely unknown. The aim of this study was to determine the number of myofibroblasts in contracting joint capsules at 3‐time points over a 24‐week period. Eighteen rabbits subjected to a surgical procedure designed to elicit a knee joint contracture were divided into three groups of six. Rabbits were sacrificed at each respective time point and myofibroblasts in the joint capsules were quantified using immunohistochemistry. The percent of myofibroblasts was significantly elevated in the operated limbs compared to the control limbs at 2 weeks (20% vs. 7%, respectively; p = 0.014). There was no difference in the percent of myofibroblasts between the operated and control limbs at 8 or 24 weeks (p = 0.96 and 0.07, respectively). The percent of myofibroblasts dropped from 20% at 2 weeks to 3.0% at 8 weeks (p < 0.001). The decrease from 8 to 24 weeks was not significant (p = 0.19). A large proportion of myofibroblasts are present in contracted joints at 2 weeks. By week 8, the proportion of myofibroblasts seem to return to normal. Interventions aimed at affecting the myofibroblast cell in order to prevent fibrosis should be instituted early.

Activities after total elbow arthroplasty.

BACKGROUND Knowledge of patient activities after total elbow arthroplasty may help delineate the true functional gains obtained after replacement. Experience suggests that some patients may perform activities excessively demanding on elbow implants, but compliance with activity restrictions recommended after elbow arthroplasty is largely unknown. MATERIALS AND METHODS All patients who underwent a primary or revision total elbow arthroplasty at a single institution from 2005 to 2007 were surveyed regarding their activity level. The University of California, Los Angeles (UCLA) activity score and Mayo Elbow Performance Score were assessed. Patients were also questioned about whether they recalled which activities were not recommended by their surgeon. RESULTS One hundred thirteen completed surveys were analyzed. There were 29 men and 84 women with a mean age of 65 years. Of the patients, 64 had primary and 49 had revision operations. The mean Mayo Elbow Performance Score was 77 points (range, 15-100 points). The mean University of California, Los Angeles activity score was 5 points (range, 1-10 points). Moderate-demand activities were performed by 94% of patients, and high-demand activities were performed by 40% of patients. Male gender and a diagnosis of fracture/nonunion was associated with increased performance of high-demand activities (P < .05). Eighty percent of patients remembered receiving postoperative restrictions, and of these patients, 83% interpreted that they were compliant with their restrictions. CONCLUSION Ninety-four percent of patients engaged in moderate-demand activities after total elbow arthroplasty. Forty percent engaged in high-demand activities. Factors correlated with more demanding activities included male gender and diagnosis of fracture/nonunion. The vast majority of patients remembered receiving postoperative restrictions.

Intra-articular decorin influences the fibrosis genetic expression profile in a rabbit model of joint contracture

Objectives The goal of this study was to determine whether intra-articular administration of the potentially anti-fibrotic agent decorin influences the expression of genes involved in the fibrotic cascade, and ultimately leads to less contracture, in an animal model. Methods A total of 18 rabbits underwent an operation on their right knees to form contractures. Six limbs in group 1 received four intra-articular injections of decorin; six limbs in group 2 received four intra-articular injections of bovine serum albumin (BSA) over eight days; six limbs in group 3 received no injections. The contracted limbs of rabbits in group 1 were biomechanically and genetically compared with the contracted limbs of rabbits in groups 2 and 3, with the use of a calibrated joint measuring device and custom microarray, respectively. Results There was no statistical difference in the flexion contracture angles between those limbs that received intra-articular decorin versus those that received intra-articular BSA (66° vs 69°; p = 0.41). Likewise, there was no statistical difference between those limbs that received intra-articular decorin versus those who had no injection (66° vs 72°; p = 0.27). When compared with BSA, decorin led to a statistically significant increase in the mRNA expression of 12 genes (p < 0.01). In addition, there was a statistical change in the mRNA expression of three genes, when compared with those without injection. Conclusions In this model, when administered intra-articularly at eight weeks, 2 mg of decorin had no significant effect on joint contractures. However, our genetic analysis revealed a significant alteration in several fibrotic genes. Cite this article: Bone Joint Res 2014;3:82–8.

Surgical capsular release reduces flexion contracture in a rabbit model of arthrofibrosis

Animal 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.

Synthetic Mesh Augmentation of Acute and Subacute Quadriceps Tendon Repair.

Quadriceps tendon rupture is an uncommon injury. To date, surgical results have been less than favorable. A novel repair technique that uses Marlex mesh (C R Bard, Murray Hill, New Jersey) has been developed. Use of this repair may allow earlier range of motion and functional restoration of extension. The authors sought to evaluate the technical feasibility, durability, and postoperative function of this repair. This study retrospectively analyzed 8 knees (7 patients) operated on with this technique from 1990 to 2011. Mean follow-up was 9 years. Average age at the time of injury was 69 years. Mean operative time was 130 minutes. No perioperative complications occurred, no patients had clinical evidence of failure, and no patients required subsequent reoperation. Mean flexion at final follow-up was 100°. Of the 8 knees, 7 knees had no extensor lag at final follow-up. Marlex mesh augmentation for quadriceps tendon ruptures has promising clinical results, despite significant comorbidities. The results showed that the technique was feasible, with low cost and reasonable operative time. The clinical results were durable, with no intraoperative complications, no re-ruptures, rare extension lag, and good range of motion. Therefore, synthetic mesh augmentation is a feasible option in acute quadriceps tendon ruptures.

What factors are predictors of emotional health in patients with full-thickness rotator cuff tears?

BACKGROUND The importance of emotional and psychological factors in treatment of patients with rotator cuff disease has been recently emphasized. Our goal was to establish factors most predictive of poor emotional health in patients with full-thickness rotator cuff tears (FTRCTs). METHODS In 2007, we began to prospectively collect data on patients with symptomatic, atraumatic FTRCTs. All patients completed a questionnaire collecting data on demographics, symptom characteristics, comorbidities, willingness to undergo surgery, and patient-related outcomes (12-Item Short Form Health Survey, American Shoulder and Elbow Surgeons score, Western Ontario Rotator Cuff Index [WORC], Single Assessment Numeric Evaluation score, Shoulder Activity Scale). Physicians recorded physical examination and imaging data. To evaluate the predictors of lower WORC emotion scores, a linear multiple regression model was fit. RESULTS Baseline data for 452 patients were used for analysis. In patients with symptomatic FTRCTs, the factors most predictive of worse WORC emotion scores were higher levels of pain (interquartile range odds ratio, -18.9; 95% confidence interval, -20.2 to -11.6; P < .0001) and lower Single Assessment Numeric Evaluation scores (rating of percentage normal that patients perceive their shoulder to be; interquartile range odds ratio, 6.2; 95% confidence interval, 2.5-9.95; P = .0012). Higher education (P = .006) and unemployment status (P = .0025) were associated with higher WORC emotion scores. CONCLUSIONS Education level, employment status, pain levels, and patient perception of percentage of shoulder normalcy were most predictive of emotional health in patients with FTRCTs. Structural data, such astendon tear size, were not. Those with poor emotional health may perceive their shoulder to be worse than others and experience more pain. This may allow us to better optimize patient outcomes with nonoperative and operative treatment of rotator cuff tears.

Shoulder arthroplasty for atraumatic osteonecrosis of the humeral head.

BACKGROUND Osteonecrosis (ON) of the humeral head represents <5% of the shoulder arthroplasty population. Depending on the stage of disease, surgeons must decide between hemiarthroplasty (HA) and total shoulder arthroplasty (TSA). To date, the peer-reviewed literature offers minimal insight into the best form of treatment of this population of patients. METHODS Between August 1973 and November 2010, 141 shoulder arthroplasties were performed for operatively confirmed ON of the humeral head; 67 HAs and 71 TSAs were observed for at least 2 years (mean, 9.3 years) or until reoperation. Indications for surgery included imaging-confirmed ON in a patient who had failed to respond to conservative treatment modalities. RESULTS Shoulder arthroplasty provided significant improvements in pain scores (P < .001), elevation (P < .01), and external rotation (P < .01) for both the HA and TSA populations. Both groups showed similar patient-reported satisfaction (>75%) and excellent/satisfactory Neer ratings (>65%). Eleven percent of HAs had moderate to severe glenoid erosion at follow-up, and 25% of glenoid components were radiographically at risk. Eight HAs and 11 TSAs underwent reoperation. The most common cause for reoperation was painful glenoid arthrosis in the HA group (7) and aseptic loosening (4) in the TSA group. The estimated 20-year survivorship of HA and TSA was 87% and 79%, respectively. CONCLUSIONS In patients with atraumatic ON of the humeral head, both HA and TSA can be expected to provide lasting pain relief and improved range of motion, with HA having longer follow-up. HA should be strongly considered in patients with atraumatic ON of the humeral head and preserved glenoid cartilage.

Use of a Bicortical Button to Safely Repair the Distal Biceps in a Two-Incision Approach: A Cadaveric Analysis

PURPOSE No consensus has been reached on the most effective anatomic approach or fixation method for distal biceps repair. It is our hypothesis that, using a cortical biceps button through a 2-incision technique, the distal biceps can be safely and anatomically repaired. METHODS A 2-incision biceps button distal biceps repair was completed on 10 fresh-frozen cadavers. The proximity of the guide pin to the critical structures of the forearm, including the posterior interosseous nerve and recurrent radial artery, was measured. The location of repair was mapped and compared with anatomic insertion. RESULTS The average distance from the tip of the guide pin to the posterior interosseous nerve was 11.4 mm (range, 8-14 mm). The average distance from the tip of the guide pin to the recurrent radial artery was 12.5 mm (range, 8-19 mm). The distal biceps tendon was repaired to the anatomic insertion site on the tuberosity using the biceps button technique in all specimens. CONCLUSIONS The 2-incision biceps button repair described here allows safe and accurate repair of the tendon to the radial tuberosity in this cadaveric study. CLINICAL RELEVANCE The goal of distal biceps repair is to safely, securely, and anatomically repair the torn biceps tendon to the radial tuberosity. The most commonly performed techniques (single anterior incision with cortical button and the double-incision procedure with bone tunnels and trough) have limitations. A 2-incision button repair safely and anatomically repairs the distal biceps tendon.

Transplantation of a tibial osteochondral allograft to restore a large glenoid osteochondral defect.

Osteochondral disease of the glenoid is a well-known cause of shoulder pain and disability in young and active patients. The etiology can be multifactorial, and disease severity can exist across a wide spectrum. Symptoms can often interfere with athletic performance, job responsibilities, and activities of daily living. Although a number of cartilage restoration techniques exist for other joints, such as the hip, knee, ankle, and elbow, restorative options for glenoid osteochondral defects are currently limited. Given the success of osteochondral allograft transplantation in other joints, the authors hypothesized that osteochondral allograft transplantation may be a reasonable option in treating osteochondral disease of the glenoid if a suitable donor source could be identified. After performing the procedure in a cadaveric model, the authors found the articular geometry of the medial tibial plateau to closely resemble that of the glenoid articular surface. This graft option is advantageous because it is readily accessible from allograft tissue banks, whereas glenoid allografts are not currently available. After failure of extensive nonoperative treatment, a former multisport athlete underwent osteochondral allograft transplantation of a large glenoid defect with a medial tibial plateau osteochondral allograft. After 1 year of follow-up, the patient showed significant improvement in the subjective shoulder value (from 40% to 99%), QuickDASH score (from 36 to 2), and American Shoulder and Elbow Score (from 46 to 92). Ultimately, medial tibial plateau allograft was a viable option for treatment of an osteochondral glenoid defect in this patient, and additional study of this treatment strategy is warranted.

Open Reduction and Internal Fixation of Three- and Four-Part Proximal Humerus Fractures

Decision making regarding operative and nonoperative management of proximal humerus fractures involves a careful assessment of patient factors, clinical exam, and radiographic parameters (both plain film and axial imaging). Open reduction and internal fixation of proximal humerus fractures is indicated for three- and four-part fractures in the young and in select patterns in older patients. Surgical treatment is optimized by paying careful attention to surgical positioning and the ability to obtain intraoperative fluoroscopic images. Following approach and tuberosity identification, a stable reduction should be obtained prior to application of a plate. A locking plate should be applied in a neutralization manner, with supplementation of plate fixation with sutures through the rotator cuff. Rehabilitation should be dictated by bone quality and strength of fixation, prioritizing healing of fracture fragments over early range of motion.