Robotic-assisted Total Knee Arthroplasty Reduces Radiographic Outliers for Low-volume Total Knee Arthroplasty Surgeons.

Background: Most studies evaluating robotic-assisted total knee arthroplasty (RA TKA) analyzed the advantages offered to high-volume surgeons. This study aims to determine if RA TKA improves radiographic or clinical outcomes for low-volume, non-arthroplasty-trained surgeons. Methods: Radiographic and early clinical outcomes of 19 RA TKAs and 41 conventional TKAs, all performed by a single, non-arthroplasty-trained orthopaedic surgeon, were compared. Radiographic outliers were based on surgeon targets and defined as tibial posterior slope outside of 0°-5°, tibial tray varus outside of 0°-3°, and the presence of notching. Clinical outcomes included inpatient narcotic usage, length of stay, range of motion, and Patient-Reported Outcome Measurement Information System scores. Results: There was a significant decrease in tibial slope outliers (RA TKA 0% vs non-RA TKA 22%, P = .024) and notching incidence (RA TKA 0% vs non-RA TKA 19.5%, P = .044) in the RA group. Tibial tray varus/valgus outliers trended lower in the RA TKA group (10.0% vs 26.8%, P = .189). Length of stay was significantly shorter in RA patients (48.0 hours [standard deviation: 25.5] vs 67.7 hours [34.3], P = .038). RA patients trended toward lower in postoperative inpatient total mean morphine equivalents usage (79.9 [89.2] vs 140.1 [169.3], P = .142) and inpatient mean morphine equivalents usage per day (30.36 [26.9] vs 45.6 [36.7], P = .105). There was no significant difference in Patient-Reported Outcome Measurement Information System scores or range of motion at first and second postoperative follow-up within 3 months. Conclusions: RA TKA reduced the incidence of radiographic outliers when compared to conventional TKA for a low-volume arthroplasty surgeon.

Optimizing the Entry Point for Medullary Hip Screws.

INTRODUCTION: Medullary hip screws (MHSs) are the most common treatment of intertrochanteric hip fractures because they can be used for varied fracture patterns and resist shortening. Identifying the appropriate MHS entry point can be intellectually and technically challenging. We aimed to quantify the variability in the ideal entry point (IEP) for MHSs. METHODS: Standing alignment radiographs of 50 patients were evaluated using TraumaCad (Brainlab). The femoral neck shaft angle and the offset from the tip of the greater trochanter (GT) to the femur's longitudinal axis ('greater trochanter offset') were measured. Five MHS system templates were superimposed on the femur's longitudinal axis, and the distance from the GT tip to MHS's top center was measured. Five independent reviewers each templated 20 images such that all images were measured at least twice. A random sample of five images was selected for all five raters to measure and to calculate an intraclass coefficient Mean IEPs were compared with an independent sample Student t -test. RESULTS: The mean GT offset was 13.5 ± 5.6 mm (range 12.9 to 26.7 mm). The mean neck shaft angle was 129.5 ± 4.0 (range 120 to 139). The mean IEP for nail systems ranged from 5.7 to 7.1 mm medial to the GT tip; there was no notable difference in pairwise comparison of nail systems or in aggregate. Intraclass coefficient for all ratings, measurements, and nail types ranged from moderate to good. Both intra-rater and inter-rater reliability were excellent. DISCUSSION AND CONCLUSION: In a sample with broad variation in femoral anatomy, there is a specific, roughly 1.5 mm wide interval that is 6.4 mm medial to the GT tip that serves as the IEP for the most common MHS systems. No notable difference seems to exist in the IEP among these MHS systems.

Preoperative Depression Is Associated With Increased Short-term Complications But Equivalent Long-term Outcomes in Total Knee Arthroplasty.

Concomitant depression negatively impacts outcomes following total knee arthroplasty (TKA). Patient-Reported Outcomes Measurement Information System (PROMIS) surveys are validated measures that quantify depression, pain, and physical function. We hypothesized that higher preoperative PROMIS-depression scores would be associated with inferior outcomes following TKA. A total of 258 patients underwent primary TKA at a tertiary academic center between June 2018 and August 2020. PROMIS scores were collected preoperatively and at 6 weeks, 3 months, 1 year, and 2 years postoperatively. Patients with preoperative PROMIS depression scores of 55 or greater were considered PROMIS depressed (PD) and patients with scores less than 55 were considered not PROMIS depressed (ND). The primary outcomes were changes in PROMIS scores. Secondary outcomes included total and daily mean morphine milligram equivalents (MME) received during admission as well as 90-day hospital readmission and 2-year all-cause revision rates. There were 66 (25.58%) patients in the PD group and 192 (74.42%) in the ND group. Patients in the PD group had improved depression scores at all follow-up intervals (P<.001) and decreased pain scores at 1 year (P=.016). Both groups experienced similar changes in function scores at each follow-up interval. Patients in the PD group had higher total (P=.176) and daily (P=.433) mean MME use while admitted. Ninety-day hospital readmissions were higher in the PD group (P=.002). There were no differences in 2-year revision rates (P=.648). Preoperative PROMIS-depression scores of 55 or greater do not negatively impact postoperative function, depression, or pain, and patients with these scores have greater improvement in depression and pain at certain intervals. Patients in the PD group had higher readmission rates. [Orthopedics. 2024;47(1):40-45.].

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.

Optimizing the Entry Point for Reconstruction Nailing of the Femur.

INTRODUCTION: Varus after antegrade medullary nailing of the proximal femur is associated with worse outcomes. Anecdotally, a more medialized "trochiformis" entry is beneficial to avoid varus with valgus-bend (greater trochanteric entry) femoral nails. However, the optimal entry point remains unknown. The purpose of this study was to define the optimal entry point for reconstruction nailing. METHODS: Using standing alignment radiographs from 51 patients, we templated the ideal entry point for straight and valgus-bend nails from three major manufacturers using TraumaCad software. We measured the distance from the tip of the trochanter to the ideal entry site for each nail. We compared piriformis (PF) with trochanteric (GT) entry for each company and across manufacturers. RESULTS: The mean greater trochanter offset from the femoral axis was 15.2 mm. The mean PF entry was 5.9 to 6.7 mm medial to the mean GT entry for each company's nail and was statistically distinct. No differences were observed in GT and PF entry points across manufacturers. Only 2 of 153 ideal GT entry points were lateral to the tip of the trochanter. An increased neck-shaft angle (NSA) and increased GT offset were correlated with a more medial ideal entry point. DISCUSSION: The ideal entry point for GT nails is similar across manufacturers and is medial to the tip of the greater trochanter; however, PF and GT entry sites remain distinct. During preoperative planning and when executing femoral nailing intraoperatively, it may also be important to consider the NSA and GT offset of a patient before committing to a certain entry point.

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.

Impact of Antibiotic-Impregnated Spacer Design in the Treatment of Periprosthetic Hip Infection.

Background: Although 2-stage exchange arthroplasty, consisting of temporary insertion of an antibiotic-impregnated cement spacer (AICS), is considered the standard of care for chronic periprosthetic joint infection (PJI) in total hip arthroplasty (THA), a consensus on the AICS design has not yet been established. Ceramic-on-polyethylene AICSs (Poly-AICS) are theorized to cause less pain and better function than cement-on-bone AICS (CemB-AICS) but use non-antibiotic-impregnated components that may harbor bacteria. This study evaluates the impact of spacer design on infection-free survivorship following THA reimplantation as well as pain and function during the interim AICS stage. Methods: A retrospective review was performed of all cases of THA PJI treated with either Poly-AICS or CemB-AICS at a single high-volume academic center. Data were collected until the final follow-up after THA reimplantation with an average follow-up duration of 2.6 years. The primary outcome was infection-free survivorship after the final reimplantation. Secondary outcomes included postoperative pain scores, opioid use, time to ambulation, length of stay, complications, and discharge disposition. Results: A total of 99 cases (67 CemB-AICS; 32 Poly-AICS) were included. There were no baseline differences between the 2 groups. There were no differences in infection-free survivorship after reimplantation in survivorship curve comparisons (P = .122) and no differences in postoperative inpatient pain scores, opioid use, length of stay, time to ambulation, complications, or discharge disposition during the AICS stage. Conclusions: Patients with THA PJI treated with Poly-AICS did not have worse infection-related outcomes despite the use of non-antibiotic-impregnated components but also did not appear to have less pain or improved function during the early AICS stage.

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.

The July Effect for Total Joint Arthroplasty Procedures.

The "July effect" refers to the assumed increased risk of complications during the months when medical school graduates transition to residency programs. The actual existence of a July effect is controversial. With this study, the authors sought to determine whether evidence exists for the presence of a July effect among total joint arthroplasty (TJA) procedures. The 2013 and 2014 Nationwide Readmission Databases were combined and all index primary and revision arthroplasty procedures were identified, and then patients from December were excluded. Thirty-day readmission rates, time to readmission, and readmission costs were analyzed by index procedure month and index procedure type. A total of 1,193,034 procedures (index primary: n=1,107,657; revision arthroplasty: n=85,377) were identified. Among all procedure types, 46,674 (3.9%) 30-day readmissions were observed. Among all procedures, an index procedure with a discharge in July resulted in the highest monthly readmission rate of the year (4.2%), which was significantly higher than the mean annual readmission rate (P<.0001). This effect was most pronounced for primary total knee arthroplasty (3.9% vs 3.6%, P<.0001). When stratifying results into teaching vs nonteaching hospitals, the highest readmission rate occurred if the index procedure occurred at a nonteaching hospital in July (4.5%, P<.0001). These data provide evidence that a July effect appears to exist for TJA procedures and is most pronounced at nonteaching institutions. Based on published mean readmission costs, the total annualized cost variation attributable to the higher readmission rate for primary TJA procedures in July is approximately $18.6 million. [Orthopedics. 2020;43(6):e543-e548.].

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.