Increased Duration and Frequency of Lateral C-Arm Draping Does Not Increase Contamination Rates.

This study sought to quantify the rate of culture-positive drape contamination with varying degrees of drape manipulation for intra-operative fluoroscopic imaging. In this prospective cohort study, 30 patients with operatively closed lower extremity fractures were evaluated. The clip-drape technique was employed to cover the emitter. Swab samples were collected for bacterial growth. A t-test was applied for statistical comparison. Three of 30 cases (10% of operations) showed evidence of contamination. There was no statistically significant difference between duration of drape use or the amount of drape manipulations. None of the 30 patients in this study developed surgical site infection 90-days post-surgery. The clip drape technique for lateral fluoroscopy appears to be effective in maintaining surgical field sterility. Moreover, the number of drape manipulations and length of time the drape was in use was not related to drape contamination. Level of Evidence: Therapeutic Level II. (Journal of Surgical Orthopaedic Advances 32(2):107-110, 2023).

The role of relaxin in anterior cruciate ligament injuries: a systematic review.

OBJECTIVE: Anterior cruciate ligament (ACL) tears are exceedingly common among the athletic population and are seen with higher incidence in females. Observational studies have noted peak ACL tear rates in the luteal phase of the menstrual cycle, a time in which the hormone relaxin peaks in serum concentration. METHODS: A systematic review of the literature was performed. Inclusion criteria specified all prospective and retrospective studies which included the role of relaxin in the pathogenesis of ACL tears. RESULTS: Six studies met inclusion criteria yielding 189 subjects from clinical studies and 51 in vitro samples. Included studies found that ACL samples exhibit selective relaxin binding. When pre-treated with estrogen prior to relaxin exposure, female ACL tissue samples exhibit increased expression of collagen degrading receptors. CONCLUSION: Relaxin displays binding specificity to the female ACL and increased serum concentrations are correlated with increased ACL tear rates in female athletes. Further research is needed in this area. LEVEL OF EVIDENCE: V.

Serum CD64 as a Marker for Chronic Periprosthetic Joint Infection.

Background: Serum cluster of differentiation 64 (CD64) has emerged as a diagnostic test for musculoskeletal infections. The purpose of this study was to evaluate the utility of serum CD64 in diagnosing periprosthetic joint infections (PJIs) compared to conventional markers like white blood count (WBC), C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), and interleukin-6 (IL-6). Methods: A prospective case-control study on patients undergoing revision hip or knee arthroplasty surgery >6 weeks after their index surgery was performed at a single institution. Whole blood samples were drawn within 24 hours prior to revision surgery for white blood count, ESR, CRP, IL-6, and CD64. Intraoperative cultures were obtained during the revision, and PJI was defined using the major criteria from the 2018 Musculoskeletal Infection Society criteria. Two-sample Wilcoxon rank-sum test and Fisher's exact test were used to determine if there were significant differences in serum laboratory values between patients with and without infection. The sensitivity, specificity, positive predictive value (PPV), negative predictive value, and accuracy of each test were calculated. Results: With an average age of 67 years, 39 patients with 15 revision THAs and 24 TKAs, were included. 19 patients (48.7%) were determined to have PJI. Patients with PJI had significantly higher CD64 (P = .036), CRP (P = .016), and ESR (P = .045). CD64 had the highest specificity (100%) and PPV (100%), moderate accuracy (69.2%), but low sensitivity (37.0%) and negative predictive value (62.5%). Conclusions: Given the high specificity, PPV, and accuracy, CD64 may be an excellent confirmatory test to help diagnose PJI.

Revision total knee arthroplasty for arthrofibrosis improves range of motion.

PURPOSE: Arthrofibrosis after primary total knee arthroplasty (TKA) is a significant contributor to patient dissatisfaction. While treatment algorithms involve early physical therapy and manipulation under anaesthesia (MUA), some patients ultimately require revision TKA. It is unclear whether revision TKA can consistently improve these patient's range of motion (ROM). The purpose of this study was to evaluate ROM when revision TKA was performed for arthrofibrosis. METHODS: A retrospective study of 42 TKA's diagnosed with arthrofibrosis from 2013 to 2019 at a single institution with a minimum 2-year follow-up was performed. The primary outcome was ROM (flexion, extension, and total arc of motion) before and after revision TKA, and secondary outcomes included patient reported outcomes information system (PROMIS) scores. Categorical data were compared using chi-squared analysis, and paired samples t tests were performed to compare ROM at three different times: pre-primary TKA, pre-revision TKA, and post-revision TKA. A multivariable linear regression analysis was performed to assess for effect modification on total ROM. RESULTS: The patient's pre-revision mean flexion was 85.6 degrees, and mean extension was 10.1 degrees. At the time of the revision, the mean age of the cohort was 64.7 years, the average body mass index (BMI) was 29.8, and 62% were female. At a mean follow-up of 4.5 years, revision TKA significantly improved terminal flexion by 18.4 degrees (p < 0.001), terminal extension by 6.8 degrees (p = 0.007), and total arc of motion by 25.2 degrees (p < 0.001). The final ROM after revision TKA was not significantly different from the patient's pre-primary TKA ROM (p = 0.759). PROMIS physical function, depression, and pain interference scores were 39 (SD = 7.72), 49 (SD = 8.39), and 62 (SD = 7.25), respectively. CONCLUSION: Revision TKA for arthrofibrosis significantly improved ROM at a mean follow-up of 4.5 years with over 25 degrees of improvement in the total arc of motion, resulting in final ROM similar to pre-primary TKA ROM. PROMIS physical function and pain scores showed moderate dysfunction, while depression scores were within normal limits. While physical therapy and MUA remain the gold standard for the early treatment of stiffness after TKA, revision TKA can improve ROM. LEVEL OF EVIDENCE: IV.

Phosphaturic Mesenchymal Tumor-induced Osteomalacia Masquerading as an Orthopedic Polytrauma Patient: A Case Report and Review of the Literature.

Introduction: Phosphaturic mesenchymal tumor (PMT) is a rare benign tumor (500 cases to date) that can present in combination with a paraneoplastic syndrome called tumor-induced osteomalacia (TIO). To the best of our knowledge, it is the first case to date that presented as an orthopedic trauma patient. Case Report: This is a case of a 61-year-old male who initially presented as a polytrauma patient, but further investigation revealed a PMT causing TIO. This report describes his initial diagnosis and management from 2015 to 2021. Conclusion: TIO resultant of PMT may lead to severe bone pain, impending fractures, and delayed or misdiagnosis. This case demonstrates the importance of careful diagnosis and a team-based approach to managing PMT and its sequelae.

Activity Recommendations After Total Hip and Total Knee Arthroplasty.

¼: A formal unsupervised activity program should be recommended to all patients recovering from total knee arthroplasty (TKA) and total hip arthroplasty (THA). ¼: In a subset of all patients undergoing TKA or THA, studies have found that an unsupervised activity program may be as efficacious as supervised physical therapy (PT) after surgery. Certain patients with inadequate independent function may continue to benefit from supervised PT. ¼: For TKA, supervised telerehabilitation has also been proven to be an effective modality, with studies suggesting equivalent efficacy compared with supervised in-person PT. ¼: Following TKA, there is no benefit to the use of continuous passive motion or cryotherapy devices, but there are promising benefits from the use of pedaling exercises, weight training, and balance and/or sensorimotor training as adjuncts to a multidisciplinary program after TKA. ¼: No standardized postoperative limitations exist following TKA, and the return to preoperative activities should be dictated by an individual's competency and should consist of methods to minimize high impact stress on the joint. ¼: Despite traditional postoperative protocols recommending range-of-motion restrictions after THA, it is reasonable to recommend that hip precautions may not be needed routinely following elective primary THA.

Is There an Optimal Cutoff for Aspiration Fluid Volume in the Diagnosis of Periprosthetic Joint Infection?

BACKGROUND: The diagnosis of periprosthetic joint infection is often challenging in the setting of low aspiration volumes, or in the presence of infection with a slow-growing organism. We sought to determine if an optimal threshold of aspiration fluid volume exists when cultures from the preoperative aspiration are compared to intraoperative cultures. METHODS: All revision total hip and knee arthroplasty procedures over 5 years at our institution were reviewed. Cases were excluded if they underwent joint lavage during aspiration, had an antibiotic spacer in place, were suspected of adverse local tissue reaction to metal debris, did not have an accurate aspiration volume recorded, or if there were no aspiration or operative cultures available. Receiver operating characteristic curves were used to evaluate aspiration volume for identifying cases with identical aspiration and culture results. RESULTS: A total of 857 revision cases were reviewed, among which 294 met inclusion criteria. There were 45 cases (15.3%) with discordant aspiration and operative cultures. The mean aspiration volume for identical cases was significantly higher than for discordant cases (19.1 vs 10.2 mL, P = .02). The proportion of slow-growing organisms was significantly greater among discordant compared to identical operative cultures (52.4% for discordant cases vs 8.2% for identical cases, P < .001). The optimal cutoff value for predicting identical cultures was 3.5 mL for typical organisms and 12.5 mL for slow-growing organisms. CONCLUSION: Aspiration cultures are more likely to correlate with intraoperative cultures with higher aspiration volumes, and the optimal aspiration volume is higher for slow-growing organisms.

The Veil of Obscuration: Additional Radiographic Sign of Posterior Shoulder Dislocation.

OBJECTIVE: To describe a new radiographic sign, "veil of obscuration", associated with posterior glenohumeral joint (shoulder) dislocations and determine its incidence and validity compared to other known classic radiographic signs. METHODS: Four-year retrospective study identified 30 acute posterior shoulder dislocation patients. Radiographs reviewed in consensus by 2 musculoskeletal radiologists for the "veil of obscuration", seen on AP shoulder radiographs and representing a comminuted fracture of the lesser tuberosity projecting over the humeral head or glenohumeral joint. Incidence of this radiographic sign of posterior glenohumeral joint dislocation in addition to other previously described classic radiographic signs, and association with other fractures, surgery, and mechanism of injury were evaluated. Continuous data was analyzed with student t-test and categorical data with Chi-Square test. RESULTS: There were 20 right and 10 left posterior shoulder dislocations. Majority of injuries resulted from vehicle crash (44%). In most cases, reverse Hill-Sachs lesion (83%) and fixed internal rotation of the humeral head (76%) were present, followed by trough line (43%) and "veil of obscuration" (40%). Trough line was seen in significantly more major trauma and vehicle crashes (78% and 46%; P=0.015), while "veil of obscuration" was seen in more seizures (86%; P=0.037) and in all surgical patients. No significant difference in presence of other classic radiographic signs in regards to surgery. CONCLUSION: The newly described radiographic sign of posterior shoulder dislocations named the "veil of obscuration" has comparable incidence as other classic radiographic signs and may be useful in the recognition and diagnosis of these injuries.