Mark E. Morrey

Elevated Postoperative Blood Glucose and Preoperative Hemoglobin A1C Are Associated with Increased Wound Complications Following Total Joint Arthroplasty

BACKGROUND Diabetes is an established risk factor for complications following total joint arthroplasty. However, the correlation between postoperative blood glucose and preoperative hemoglobin A1C levels with complications following total joint arthroplasty is not well described. METHODS All patients undergoing elective primary total joint arthroplasty at our institution from 2004 through 2011 with both postoperative blood glucose and preoperative hemoglobin A1C levels were identified in a retrospective review. From among 1702 patients, those with wound complications within thirty days after the index arthroplasty were identified. A control group matched for exact age, sex, procedure, tourniquet use, surgical approach, and use of antibiotic cement was also created. Thirty patients met the study group inclusion criteria. The mean patient age was seventy-two years (range, fifty-three to eighty-nine years); the majority (53%) of patients were female. RESULTS The odds ratio for developing a wound complication was 3.75 (95% confidence interval, 1.25 to 11.22; p = 0.02) in patients with a mean postoperative glucose of >200 mg/dL, 3.0 (95% confidence interval, 0.97 to 9.30; p = 0.08) in patients with a maximum postoperative blood glucose of >260 mg/dL, and 9.0 (95% confidence interval, 1.14 to 71.20; p = 0.03) in patients with a preoperative hemoglobin A1C value of >6.7%. CONCLUSIONS Patients with a mean postoperative blood glucose of >200 mg/dL or a preoperative hemoglobin A1C level of >6.7% are at increased risk for wound complications following elective primary total joint arthroplasty. These results show that poor preoperative and postoperative glucose control is independently associated with wound complications.

Increased long-term survival of posterior cruciate-retaining versus posterior cruciate-stabilizing total knee replacements.

BACKGROUND Considerable debate remains regarding the use of posterior cruciate-retaining or posterior cruciate-stabilizing designs for total knee arthroplasty. Multiple studies have investigated kinematic, radiographic, and clinical outcomes of both. Nevertheless, long-term survivorship analyses directly comparing the two designs have not been performed, to our knowledge. Our goal was to analyze the fifteen-year survival of posterior cruciate-retaining and posterior cruciate-stabilizing total knee replacements at our institution. METHODS A retrospective review identified 8117 total knee arthroplasties (5389 posterior cruciate-retaining and 2728 posterior cruciate-stabilizing) that had been performed from 1988 to 1998. This range was chosen because both designs were used in high volumes at our institution during this period. Patients were followed via our total joint registry at one, two, and five years after the arthroplasty and every five years thereafter. Aseptic revision surgery was the primary end point of our analysis. Implant survival was estimated with Kaplan-Meier curves. RESULTS Survival at fifteen years was 90% for posterior cruciate-retaining total knee replacements, compared with 77% for posterior cruciate-stabilizing total knee replacements (p < 0.001). In knees with preoperative deformity, the fifteen-year survival was 90% for posterior cruciate-retaining total knee replacements, compared with 75% for posterior cruciate-stabilizing total knee replacements (p < 0.04). Likewise, in knees without preoperative deformity, the fifteen-year survival was 88% for posterior cruciate-retaining total knee replacements, compared with 78% for posterior cruciate-stabilizing total knee replacements (p < 0.001). After adjustment for age, sex, preoperative diagnosis, and preoperative deformity, the risk of revision was significantly lower in knees with a posterior cruciate-retaining total knee replacement (p < 0.001; hazard ratio = 0.5; 95% confidence interval, 0.4 to 0.6). CONCLUSIONS In evaluating the implants used at our institution for total knee arthroplasty during the study period, posterior cruciate-retaining prostheses had significantly improved survival in comparison with posterior cruciate-stabilizing prostheses at fifteen years. Furthermore, this significant difference remained when accounting for age, sex, diagnosis, and deformity.

New rabbit knee model of posttraumatic joint contracture: Indirect capsular damage induces a severe contracture

Reported models of joint contracture fail to result in severe motion loss. Our purpose was to develop a rabbit model of knee contracture and compare it to another well‐accepted model to determine if more severe stiffness can be achieved. Sixteen skeletally mature New Zealand White female rabbits had their right knee operated to create 3‐mm defects on the noncartilaginous portions of the femoral condyles, hyperextend the joint to disrupt the posterior capsule, and immobilize the joint in maximum flexion with a Kirschner‐wire for 8 weeks (group I). Sixteen additional rabbits were operated on using an identical protocol except for the absence of capsular injury (group II). In each group, mechanical testing was performed at the time of Kirschner‐wire release in eight animals, and 16 weeks after remobilization in eight animals. At immobilization release, the average contracture was 76 ± 24° in group I versus 20 ± 10° in group II (p < 0.001). Sixteen weeks after remobilization, the mean contracture was 49 ± 15° group I versus 11 ± 10° in group II (p < 0.001). When associated with bone perforations and immobilization in forced flexion, injury to the posterior capsule results in a severe contracture in the rabbit knee.

Arthroscopic management of native shoulder septic arthritis

BACKGROUND There is little information on the results of arthroscopic treatment of native shoulder sepsis. Therefore, the purpose of this study was to determine the presentation, preoperative indices, intraoperative findings, and outcomes related to native shoulder sepsis treated with arthroscopy. MATERIALS AND METHODS We retrospectively reviewed 50 consecutive native shoulders with septic arthritis between 1994 and 2008. Patients (75% male) were an average age of 66 years. Four patients had bilateral involvement. All underwent arthroscopic irrigation and debridement. The mean follow-up was 31 months (range, 1-185 months). RESULTS Patients were immunocompromised in 57% of cases. The mean preoperative values (normal reference ranges) included white blood cell count, 13 × 10(9)/L (3.5-10.5 × 10(9)/L); erythrocyte sedimentation rate, 66 mm/h (0-29 mm/h), and C-creative protein, 83 mg/L (0-10 mg/L). The average aspiration cell count was 110,988, with a mean differential of 87% neutrophils. The most common organisms were methicillin-susceptible Staphylococcus aureus (44%). Repeat irrigation and debridement was required within the first month in 16 of 50 shoulders (32%). Within 1 year, 17% of patients had died. Final Gächter staging was I or II for 32 shoulders and III or IV for 18 shoulders. CONCLUSIONS Most patients with native shoulder sepsis are elderly and immunocompromised and present with increased inflammatory markers and a supporting aspiration cell count. Patients and surgeons must be aware that after initial arthroscopy, 1 in 3 patients will require additional surgical intervention, whether anticipated or not. LEVEL OF EVIDENCE Level IV, Case Series, Treatment Study.

Posttraumatic elbow arthritis in the young adult: evaluation and management.

Abstract Degenerative joint disease following trauma to the elbow is difficult to manage in any patient. However, this condition becomes substantially more challenging in the young, active population. Increased activity demands and limited functional capacity of total elbow arthroplasty mean that joint arthroplasty should be regarded as a salvage procedure. The primary goal of treatment is to restore a pain‐free or minimally painful functional joint while preserving future surgical options. This requires accurate assessment of the primary patient complaint, be it terminal pain and stiffness or pain along the entire arc of motion. Patients who report stiffness and pain at terminal motion may benefit from arthroscopic or open osteocapsular débridement. Those with advanced degenerative changes and pain throughout the entire arc of motion may require joint resurfacing with interposition arthroplasty, partial joint arthroplasty, or total joint arthroplasty.

Allograft-Prosthetic Composite Reconstruction for Massive Bone Loss Including Catastrophic Failure in Total Elbow Arthroplasty

INTRODUCTION Revision total elbow arthroplasty with an allograft-prosthetic composite is a difficult salvage procedure due to massive bone loss and a compromised soft-tissue envelope. High failure rates in prior studies of patients treated with allograft-prosthetic composites and an increased burden of revision total elbow arthroplasties necessitate optimized reconstructive techniques to improve incorporation of allograft-prosthetic composites. The goal of this report is to describe novel techniques for, and outcomes of, reconstructions done with an allograft-prosthetic composite. METHODS From 2003 through 2008, twenty-five patients underwent revision total elbow arthroplasty with an allograft-prosthetic composite in the humerus (six), ulna (eighteen), or both (one). Indications included aseptic implant loosening with a fracture or cortical breach (eleven), aseptic implant loosening without fracture (three), infection (seven), failed implants (one), bone loss after hemiarthroplasty (one), nonunion (one), and resection arthroplasty (one). Three reconstructive strategies were used: intussusception of the allograft-prosthesis-composite (Type I), strut-like coaptation (Type II), and side-to-side contact between the cortices of the allograft-prosthetic composite and the host bone (Type III). The outcomes that were examined included the Mayo Elbow Performance Score (MEPS), radiographic union, and overall revision and complication rates. RESULTS The mean MEPS improved from 30 points preoperatively to 84 points at the time of follow-up. Ninety-two percent of the allograft-prosthetic composites incorporated. There were eight major and four minor complications in nine patients, leading to nine reoperations in six patients. Complications included infection (three), fracture (three), nonunion (one), malunion (one), skin necrosis (one), triceps insufficiency/weakness (two), and ulnar nerve paresthesia (one). Four of the twenty-five patients had definitive resection arthroplasty, one had osteosynthesis, and one had a successful revision, so twenty-one (84%) of the twenty-five had a functional elbow. Five of seven infected joints were salvaged with staged allograft-prosthesis-composite procedures. CONCLUSIONS Larger graft-host contact areas in the three types of allograft-prosthetic composites provided good functional outcomes and a high rate of union compared with prior experience and resection arthroplasty. Allograft-prosthetic composites can be a safe, reliable option with an acceptable complication rate for revision total elbow arthroplasty.

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.

A layered electrospun and woven surgical scaffold to enhance endogenous tendon repair.

Surgical reattachments of tendon to bone in the rotator cuff are reported to fail in around 40% of cases. There are no adequate solutions to improve tendon healing currently available. Electrospun, sub-micron materials, have been extensively studied as scaffolds for tendon repair with promising results, but are too weak to be surgically implanted or to mechanically support the healing tendon. To address this, we developed a bonding technique that enables the processing of electrospun sheets into multi-layered, robust, implantable fabrics. Here, we show a first prototype scaffold created with this method, where an electrospun sheet was reinforced with a woven layer. The resulting scaffold presents a maximum suture pull out strength of 167N, closely matched with human rotator cuff tendons, and the desired nanofibre-mediated bioactivity in vitro and in vivo. This type of scaffold has potential for broader application for augmenting other soft tissues.

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.