Early Total Hip Arthroplasty is a Cost-Effective Treatment for Severe Radiographic Slipped Capital Femoral Epiphysis Over an Individual's Lifetime.

BACKGROUND: Slipped capital femoral epiphysis (SCFE) causes degenerative changes warranting total hip arthroplasty (THA) in approximately 50% of patients by age 60 years. For severe SCFE, a reorienting intertrochanteric osteotomy (ITO) following in situ pinning (ISP) can decrease impingement with hip flexion, but by altering proximal femoral geometry, complicates subsequent conversion THA. We hypothesized that increasing implant survivorship would affect the most cost-effective treatment strategy (ISP followed by ITO [ISP + ITO] with later THA versus ISP alone [ISPa] with earlier THA) over a patient's lifetime. METHODS: A state-transition Markov model was constructed to analyze the cost-effectiveness of either ISPa or ISP + ITO over a 60-year time horizon for children who have severe, stable SCFE. Transition probabilities associated with implant and native hip survivorship, state utilities, and costs were derived from the literature. Sensitivity analyses assessed the model robustness. Incremental cost-effectiveness ratios (ICERs) were compared to a societal willingness to pay (WTP) of $100,000 per quality-adjusted life year (QALY). RESULTS: Over a 60-year horizon, ISPa was costlier ($291,836) than ISP + ITO ($75,227) but achieved overall better outcomes (51.4 QALYs ISPa versus 48.7 QALYs ISP + ITO), rendering ISPa cost-effective with an ICER of $80,980/QALY. Implant survivorship and time horizon were sensitive variables. CONCLUSION: Based upon current implant performance, ISPa with subsequent earlier THA is cost-effective when considering an individual's life expectancy and thereby deserves consideration in patients who have severe SCFE. Without clear level 1 clinical data, our economic model considers a difficult problem, while providing families and clinicians with a framework for understanding treatment options. LEVEL OF EVIDENCE: Economic and decision analysis, Level III.

Cannabis Use Does Not Affect Outcomes After Total Hip Arthroplasty.

BACKGROUND: Cannabis use in patients undergoing arthroplasty has increased with ongoing legalization throughout the United States. The purpose of this study was to report total hip arthroplasty (THA) outcomes in patients self-reporting cannabis use. METHODS: There were 74 patients who underwent primary THA from January 2014 to December 2019 at a single institution with minimum 1-year follow-up who had their self-reported cannabis use retrospectively reviewed. Patients who had a history of alcohol or illicit drug abuse were excluded. A match control was conducted based on age; body mass index; sex; Charlson Comorbidity Index; insurance status; and use of nicotine, narcotics, antidepressants, or benzodiazepines to patients undergoing THA who did not self-report cannabis use. Outcomes included Harris Hip Score (HHS), Hip Disability and Osteoarthritis Outcome Score for Joint Reconstruction (HOOS JR), in hospital morphine milligram equivalents (MMEs) consumed, outpatient MMEs prescribed, in hospital lengths of stay (LOS), postoperative complications, and readmissions. RESULTS: There was no difference in the preoperative, postoperative, or change in Harris Hip Score or HOOS JR between cohorts. There was also no difference in hospital MMEs consumed (102.4 versus 101, P = .92), outpatient MMEs prescribed (119 versus 156, P = .11) or lengths of stay (1.4 versus 1.5 days, P = .32). Also, readmissions (4 versus 4, P = 1.0) and reoperations (2 versus 1, P = .56) were not different between groups. CONCLUSION: Self-reported cannabis use does not influence 1-year outcomes after THA. Further studies are warranted to determine the efficacy and safety of perioperative cannabis use after THA to help guide orthopaedic surgeons in counseling patients.

An Innovative Seven-year Physician Scientist Residency Training Program That Addresses the Shortage of Academic Surgeons.

Due to the declining number of scientifically trained physicians and increasing demand for high-quality literature, our institution pioneered a seven-year Physician Scientist Training Program (PSTP) to provide research-oriented residents the knowledge and skills for a successful academic career. The present study sought to identify orthopaedic surgeons with MD/PhD degrees, residency programs with dedicated research tracks, and to assess the effectiveness of the novel seven-year program in training prospective academic orthopaedic surgeons. Surgeons with MD/PhD degrees account for 2.3% of all 3,408 orthopaedic faculty positions in U.S. residency programs. During the last 23 years, our PSTP residents produced 752 peer-reviewed publications and received $349,354 from 23 resident-authored extramural grants. Eleven of our seven-year alumni practice orthopaedic surgery in an academic setting. The seven-year PSTP successfully develops clinically trained surgeon scientists with refined skills in basic science and clinical experimental design, grant proposals, scientific presentations, and manuscript preparation. (Journal of Surgical Orthopaedic Advances 31(3):144-149, 2022).

Improved osseointegration using porcine xenograft compared to demineralized bone matrix for the treatment of critical defects in a small animal model.

BACKGROUND: Autograft (AG) is the gold standard bone graft due to biocompatibility, osteoconductivity, osteogenicity, and osteoinductivity. Alternatives include allografts and xenografts (XG). METHODS: We investigated the osseointegration and biocompatibility of a decellularized porcine XG within a critical defect animal model. We hypothesized that the XG will result in superior osseointegration compared to demineralized bone matrix (DBM) and equivalent immune response to AG. Critical defects were created in rat femurs and treated with XG, XG plus bone morphogenetic protein (BMP)-2, DBM, or AG. Interleukin (IL)-2 and IFN-gamma levels (inflammatory markers) were measured from animal blood draws at 1 week and 1 month post-operatively. At 1 month, samples underwent micro-positron-emission tomography (microPET) scans following 18-NaF injection. At 16 weeks, femurs were retrieved and sent for micro-computerized tomography (microCT) scans for blinded grading of osseointegration or were processed for histologic analysis with tartrate resistant acid phosphatase (TRAP) and pentachrome. RESULTS: Enzyme linked immunosorbent assay testing demonstrated greater IL-2 levels in the XG vs. AG 1 week post-op; which normalized by 28 days post-op. MicroPET scans showed increased uptake within the AG compared to all groups. XG and XG + BMP-2 showed a trend toward increased uptake compared with DBM. MicroCT scans demonstrated increased osseointegration in XG and XG + BMP groups compared to DBM. Pentachrome staining demonstrated angiogenesis and endochondral bone formation. Furthermore, positive TRAP staining in samples from all groups indicated bone remodeling. CONCLUSIONS: These data suggest that decellularized and oxidized porcine XG is biocompatible and at least equivalent to DBM in the treatment of a critical defect in a rat femur model.

Tourniquet Use Improves Cement Penetration and Reduces Radiolucent Line Progression at 5 Years After Total Knee Arthroplasty.

BACKGROUND: Although the effect of tourniquet use during total knee arthroplasty (TKA) on functional outcomes is controversial, there are little data examining cement penetration and implant stability. This study examines the effect of tourniquet use on cement penetration and radiolucent line (RLL) progression. METHODS: Patients undergoing primary total knee arthroplasty with a single surgeon, implant, and cement with minimum 5-year follow-up were retrospectively reviewed. Tourniquet use was defined as 30 minutes minimum, while no tourniquet was 0 minutes. Patients were 1:1 matched (n = 61 per group) by age (±5), gender, body mass index (±5), and follow-up (±2 years). Cement penetration and RLL were measured on the tibia at 6 weeks, and RLL at 1, 2, and 5 years postoperatively using the Knee Society Radiographic Evaluation System. RESULTS: Cement penetration was significantly increased in the tourniquet group in anterior-posterior zones 1 (2.16 vs 1.03 mm, P < .0005), 2 (2.23 vs 1.51 mm, P < .0005), and 5 (8.56 vs 6.3 mm, P = .009), and lateral zones 1 (2.89 vs 2.17 mm, P < .0005), 2 (2.86 vs 2.12 mm, P < .0005), 3P (3.99 vs 3.5 mm, P = .039), and 5 (8.18 vs 5.93 mm, P = .006). Cumulative cement penetration averaged 34.48 vs 43.33 mm in the tourniquet group (P < .005). Progression of RLL >2 mm was observed in 27.8% (17/61) vs 11.4% (7/61) of patients in the tourniquet group (P < .005). There were 2 failures for aseptic tibial loosening in the no tourniquet group. CONCLUSION: Tourniquet use improves cement penetration and reduces RLL progression. Dryer surfaces during cementation may improve penetration, resulting in superior initial fixation strength and potentially reducing the long-term risk of aseptic loosening.

A Prophylactic Tibial Stem Reduces Rates of Early Aseptic Loosening in Patients with Severe Preoperative Varus Deformity in Primary Total Knee Arthroplasty.

BACKGROUND: Patients with a preoperative varus deformity >8 degrees are at increased risk of aseptic loosening after total knee arthroplasty. This study analyzes the effect of a tibial stem on the rate of aseptic loosening in patients with a severe preoperative varus deformity. METHODS: Patients with a preoperative varus deformity of >8 degrees and 2-year minimum follow-up with a stemmed tibial component (n = 67) were matched 1:2 to patients with a similar preoperative varus deformity with a standard tibial component (n = 134). Radiolucent lines were measured on the tibia at 6 weeks, 1 year, and 2 years postoperatively using the Knee Society Radiographic Evaluation System. Failure was defined as revision due to aseptic loosening of the tibial component. Outcomes were evaluated using Student's t-tests and log-rank tests. RESULTS: Patients with tibial stems had greater preoperative deformity (12.9 vs 11.3 degrees, P = .004). There was no difference in postoperative alignment (1.7 vs 2.1 degrees varus, P = .25) or tibial component angle (1.8 vs 2.1 degrees varus, P = .33). Patients with stems were more likely to have more constraint (44.8% vs 1.5%, P < .001). Progression of radiolucent lines >2 mm was observed in 17.6% (23/134) vs 5.97% (4/67) of patients in the stem group (P = .03). Rates of aseptic loosening were lower in the stem group (0% vs 5.15%, P = .05). CONCLUSION: Despite worse preoperative deformity and higher utilization of constraint, tibial stem use in patients with severe preoperative varus deformity resulted in lower rates of aseptic loosening. Prophylactic use of stems in these patients may help increase implant survival.

Incidence and Predictive Risk Factors of Postoperative Urinary Retention After Primary Total Knee Arthroplasty.

BACKGROUND: Postoperative urinary retention (POUR) after total knee arthroplasty (TKA) may cause urologic injury and delay patient discharge. This study measures the incidence of POUR and identifies predictive risk factors. METHODS: Two-hundred seventy-one consecutive patients undergoing primary unilateral TKA were prospectively enrolled. Bladder scans were performed in the postanesthesia care unit (PACU) and every four hours thereafter. POUR was defined as >400cc with inability to void and was treated with catheterization. Patient demographics, urologic history, operative data, perioperative medications, and bladder scanner volumes were investigated with the univariate and multivariate logistic regression analysis. RESULTS: Fifty-five patients (20%) developed POUR. Compared with non-POUR patients, PACU bladder scan volumes were greater in patients who developed POUR (344cc vs 120cc, P < .001). POUR patients had lower BMI (27.8 vs 29.4, P = .03), longer operative duration (83.9 vs 76.0 minutes, P = .002), and lower ASA scores (2.2 vs 2.4, P = .02). Total intravenous fluid was equivalent between groups (1134cc vs 1185cc, P = .41). POUR patients received less narcotics measured by morphine milligram equivalents (16.1 vs 23.9, P < .001). Fifteen variables including spinal type (bupivacaine and ropivacaine) and paralytic use were not predictive of POUR. Potentially predictive variables included anesthetic types administered (spinal, general, regional, and combination) and perioperative administration of nonsteroidal anti-inflammatory drugs (NSAIDs), glycopyrrolate, and muscle relaxants. The multivariate analysis showed that NSAIDs (P = .05) and glycopyrrolate (P = .04) were significant predictors. CONCLUSION: A significant percentage of patients develop POUR after TKA. Select patient demographics and PACU bladder scanning may identify those at risk. Appropriate pain control and judicious use of perioperative NSAIDs and glycopyrrolate may help minimize the risk of POUR.

Bone xenotransplantation: A review of the history, orthopedic clinical literature, and a single-center case series.

BACKGROUND: One-half of all orthopedic surgeries require bone grafting for successful outcomes in fusions, reconstructive procedures, and the treatment of osseous defects resulting from trauma, tumor, infection, or congenital deformity. Autologous bone grafts are taken from the patient's own body and remain the "gold standard" graft choice but are limited in supply and impart significant patient morbidity. Xenograft bone is an attractive alternative from donors with controlled biology, in large supply and at a theoretically lower cost. Clinical results with xenograft bone for orthopedic applications have been mixed in the limited clinical trials published. METHODS: In the current review, we introduce fundamental principles of bone grafting, systematically review all orthopedic clinical studies reporting outcomes on patients transplanted with xenograft bone, and we present our own clinical results from patients grafted with bovine bone in foot and ankle reconstructive procedures. RESULTS: Thirty-one clinical studies were identified for review and the majority (47%) were from spine surgery literature. Favorable results were reported in 44% of studies while 47% of studies reported poor outcomes and discouraged use of xenograft bone products. In our own clinical series, xenograft failed to integrate with host bone in 58% of cases and persistent pain was reported in 83% of cases. CONCLUSIONS: This is the first systematic review of clinical results reported after bone xenotransplantation for orthopaedic surgery applications. Current literature does not support the use of xenograft bone products and our institution's results are consistent with this conclusion. Our laboratory has reported promising pre-clinical results with a xenograft product derived from porcine cancellous bone, but additional testing is required before considering clinical translation.

Investigating the Osteoinductive Potential of a Decellularized Xenograft Bone Substitute.

Bone grafting is the second most common tissue transplantation procedure worldwide. One of the alternative methods for bone repair under investigation is a tissue-engineered bone substitute. An ideal property of tissue-engineered bone substitutes is osteoinductivity, defined as the ability to stimulate primitive cells to differentiate into a bone-forming lineage. In the current study, we use a decellularization and oxidation protocol to produce a porcine bone scaffold and examine whether it possesses osteoinductive potential and can be used to create a tissue-engineered bone microenvironment. The decellularization protocol was patented by our lab and consists of chemical decellularization and oxidation steps using combinations of deionized water, trypsin, antimicrobials, peracetic acid, and triton-X100. To test if the bone scaffold was a viable host, preosteoblasts were seeded and analyzed for markers of osteogenic differentiation. The osteoinductive potential was observed in vitro with similar osteogenic markers being expressed in preosteoblasts seeded on the scaffolds and demineralized bone matrix. To assess these properties in vivo, scaffolds with and without preosteoblasts preseeded were subcutaneously implanted in mice for 4 weeks. MicroCT scanning revealed 1.6-fold increased bone volume to total volume ratio and 1.4-fold increase in trabecular thickness in scaffolds after implantation. The histological analysis demonstrates new bone formation and blood vessel formation with pentachrome staining demonstrating osteogenesis and angiogenesis, respectively, within the scaffold. Furthermore, CD31+ staining confirmed the endothelial lining of the blood vessels. These results demonstrate that porcine bone maintains its osteoinductive properties after the application of a patented decellularization and oxidation protocol developed in our laboratory. Future work must be performed to definitively prove osteogenesis of human mesenchymal stem cells, biocompatibility in large animal models, and osteoinduction/osseointegration in a relevant clinical model in vivo. The ability to create a functional bone microenvironment using decellularized xenografts will impact regenerative medicine, orthopedic reconstruction, and could be used in the research of multiple diseases.

A porcine xenograft-derived bone scaffold is a biocompatible bone graft substitute: An assessment of cytocompatibility and the alpha-Gal epitope.

BACKGROUND: Xenografts are an attractive alternative to traditional bone grafts because of the large supply from donors with predictable morphology and biology as well as minimal risk of human disease transmission. Clinical series involving xenograft bone transplantation, most commonly from bovine sources, have reported poor results with frequent graft rejection and failure to integrate with host tissue. Failures have been attributed to residual alpha-Gal epitope in the xenograft which humans produce natural antibody against. To the authors' knowledge, there is currently no xenograft-derived bone graft substitute that has been adopted by orthopedic surgeons for routine clinical use. METHODS: In the current study, a bone scaffold intended to serve as a bone graft substitute was derived from porcine cancellous bone using a tissue decellularization and chemical oxidation protocol. In vitro cytocompatibility, pathogen clearance, and alpha-Gal quantification tests were used to assess the safety of the bone scaffold intended for human use. RESULTS: In vitro studies showed the scaffold was free of processing chemicals and biocompatible with mouse and human cell lines. When bacterial and viral pathogens were purposefully added to porcine donor tissue, processing successfully removed these pathogens to comply with sterility assurance levels established by allograft tissue providers. Critically, 98.5% of the alpha-Gal epitope was removed from donor tissue after decellularization as shown by ELISA inhibition assay and immunohistochemical staining. CONCLUSIONS: The current investigation supports the biologic safety of bone scaffolds derived from porcine donors using a decellularization protocol that meets current sterility assurance standards. The majority of the highly immunogenic xenograft carbohydrate was removed from donor tissue, and these findings support further in vivo investigation of xenograft-derived bone tissue for orthopedic clinical application.

History of Breast Cancer Increases 90-Day Pulmonary Embolism Rates and Reimbursements After Total Hip Arthroplasty: A National Matched-Pair Analysis.

BACKGROUND: Rates of total hip arthroplasty (THA) are projected to increase in the coming decades. Multiple studies have focused on identifying risk factors for adverse events after joint arthroplasty, and recent attention has been directed toward cancer. Very limited data have been published examining the effects of history of malignancy on outcomes after THA. With a concomitant increase in breast cancer diagnosis and treatments in recent years, it is expected that orthopedic surgeons will likely see more breast cancer survivors in clinic. The purpose of this study is to examine the effects of a personal history of breast cancer on 90-day outcomes after THA. METHODS: We conducted a retrospective case-control study of the entire Medicare records. The endpoints of this study included length of stay, medical complications, surgical complications, and costs (examined here as reimbursements). Patients were matched by age and gender in order to decrease confounding. A 1:1 matching was performed. RESULTS: After age and demographics matching, our findings demonstrated that patients with a history of breast cancer have increased rates of pulmonary embolism (0.59% vs 0.45%, P = .003), increased use of chest computed tomography (1.72% vs 1.18%, P < .001), and higher mean 90-day reimbursements (mean $15,432 vs mean $14,701, P = .011) in the 90 days following surgery. Other medical and surgical complications were equally distributed in both cohorts. CONCLUSION: Surgeons should be aware of the increased rate of pulmonary embolism and have a more aggressive thromboprophylaxis protocol in these patients.

The Development of a Xenograft-Derived Scaffold for Tendon and Ligament Reconstruction Using a Decellularization and Oxidation Protocol.

PURPOSE: To evaluate the biological, immunological, and biomechanical properties of a scaffold derived by architectural modification of a fresh-frozen porcine patella tendon using a decellularization protocol that combines physical, chemical, and enzymatic modalities. METHODS: Porcine patellar tendons were processed using a decellularization and oxidation protocol that combines physical, chemical, and enzymatic modalities. Scaffolds (n = 88) were compared with native tendons (n = 70) using histologic, structural (scanning electron microscopy, porosimetry, and tensile testing), biochemical (mass spectrometry, peracetic acid reduction, DNA quantification, alpha-galactosidase [α-gal] content), as well as in vitro immunologic (cytocompatibility, cytokine induction) and in vivo immunologic nonhuman primate analyses. RESULTS: A decrease in cellularity based on histology and a significant decrease in DNA content were observed in the scaffolds compared with the native tendon (P < .001). Porosity and pore size were increased significantly (P < .001). Scaffolds were cytocompatible in vitro. There was no difference between native tendons and scaffolds when comparing ultimate tensile load, stiffness, and elastic modulus. The α-gal xenoantigen level was significantly lower in the decellularized scaffold group compared with fresh-frozen, nondecellularized tissue (P < .001). The in vivo immunological response to implanted scaffolds measured by tumor necrosis factor-α and interleukin-6 levels was significantly (P < .001) reduced compared with untreated controls in vitro. These results were confirmed by an attenuated response to scaffolds in vivo after implantation in a nonhuman primate model. CONCLUSIONS: Porcine tendon was processed via a method of decellularization and oxidation to produce a scaffold that possessed significantly less inflammatory potential than a native tendon, was biocompatible in vitro, of increased porosity, and with significantly reduced amounts of α-gal epitope while retaining tensile properties. CLINICAL RELEVANCE: Porcine-derived scaffolds may provide a readily available source of material for musculoskeletal reconstruction and repair while eliminating concerns regarding disease transmission and the morbidity of autologous harvest.

Obesity has no effect on outcomes following unicompartmental knee arthroplasty.

PURPOSE: Although obesity has historically been described as a contraindication to UKA, improved outcomes with modern UKA implant designs have challenged this perception. The purpose of this study was to assess the influence of obesity on the outcomes of UKA with a robotic-assisted system at a minimum follow-up of 24 months with the hypothesis that obesity has no effect on robotic-assisted UKA outcomes. METHODS: There were 746 medial robotic-assisted UKAs (672 patients) with a mean age of 64 years (SD 11) and a mean follow-up time of 34.6 months (SD 7.8). Mean overall body mass index (BMI) was 32.1 kg/m2 (SD 6.5), and patients were stratified into seven weight categories according to the World Health Organization classification. RESULTS: Patient BMI did not influence the rate of revision surgery to TKA (5.8 %) or conversion from InLay to OnLay design (1.7 %, n.s.). Mean postoperative Oxford knee score was 37 (SD 11) without correlation with BMI (n.s.). The type of prosthesis (InLay/OnLay) regardless of BMI had no influence on revision rate (n.s.). BMI did not influence 90-day readmissions (4.4 %, n.s.), but showed significant correlation with higher opioid medication requirements and a higher number of physical therapy session needed to reach discharge goals (p = 0.031). CONCLUSION: These findings suggest that BMI does not influence clinical outcomes and readmission rates of robotic-assisted UKA at mid-term. The classic contraindication of BMI >30 kg/m2 may not be justified with the use of modern UKA designs or techniques. LEVEL OF EVIDENCE: IV.

A Bundle Protocol to Reduce the Incidence of Periprosthetic Joint Infections After Total Joint Arthroplasty: A Single-Center Experience.

BACKGROUND: Periprosthetic joint infection (PJI) represents a devastating complication of total hip arthroplasty (THA) or total knee arthroplasty (TKA). Modifiable patient risk factors as well as various intraoperative and postoperative variables have been associated with risk of PJI. In 2011, our institution formulated a "bundle" to optimize patient outcomes after THA and TKA. The purpose of this report is to describe the "bundle" protocol we implemented for primary THA and TKA patients and to analyze its impact on rates of PJI and readmission. METHODS: Our bundle protocol for primary THA and TKA patients is conceptually organized about 3 chronological periods of patient care: preoperative, intraoperative, and postoperative. The institutional total joint database and electronic medical record were reviewed to identify all primary THAs and TKAs performed in the 2 years before and following implementation of the bundle. Rates of PJI and readmission were then calculated. RESULTS: Thirteen of 908 (1.43%) TKAs performed before the bundle became infected compared to only 1 of 890 (0.11%) TKAs performed after bundle implementation (P = .0016). Ten of 641 (1.56%) THAs performed before the bundle became infected, which was not statistically different from the 4 of 675 (0.59%) THAs performed after the bundle that became infected (P = .09). CONCLUSION: The bundle protocol we describe significantly reduced PJIs at our institution, which we attribute to patient selection, optimization of modifiable risk factors, and our perioperative protocol. We believe the bundle concept represents a systematic way to improve patient outcomes and increase value in total joint arthroplasty.

Incidence of heterotopic ossification in direct anterior vs posterior approach to total hip arthroplasty: a retrospective radiographic review.

PURPOSE: To investigate the prevalence of heterotopic ossification following direct anterior approach total hip arthroplasty compared to posterior approach, performed by a single surgeon at one institution METHODS: All primary THAs performed by the senior author (JEL) over a 70-month period were reviewed, including 235 DAA and 120 posterior THAs. Brooker's system was used to grade HO at a minimum of six months follow-up. RESULTS: Patients undergoing DAA were less likely to develop clinically significant HO compared to posterior THA (p = 0.04). The overall incidence of HO following DAA THA was 24.3 % (3 % grade 3 and 0 % grade 4), and following posterior THA was 27.5 % (4.2 % grade 3 and 3.3 % grade 4). CONCLUSIONS: Lower rates of clinically significant (Brooker grade 3 and 4) HO were observed in DAA THA than in posterior approach THA. This data may be instructive when approaching THA candidates with conditions that predispose them to HO.

Effects of patellofemoral overstuffing on knee flexion and patellar kinematics following total knee arthroplasty: a cadaveric study.

PURPOSE: The purpose of this study was to test the hypothesis that overstuffing the patellofemoral joint during total knee arthroplasty (TKA) would decrease passive knee flexion and alter patellar kinematics during knee flexion. METHODS: Ten cadaveric knees were implanted with cruciate-retaining TKAs, and the patellofemoral joint was overstuffed in 2-mm increments with custom-augmented patellar prostheses (+2 mm through +8 mm). Changes to knee flexion, patellar shift, tilt and rotation were measured with an imageless optical-tracking computer navigation system. RESULTS: Knee flexion decreased an average 1.2° with each additional 2 mm of patellar thickness. Compared with control TKA (+0 mm), no significant decrease in knee flexion was detected until the patellofemoral joint was overstuffed with the +8-mm patellar prosthesis. Kinematic tracking data showed significantly greater lateral shift of patella with the +6- and +8-mm prostheses and significantly greater lateral tilt with the +8-mm prosthesis. Overstuffing had no appreciable effect on patellar rotation. CONCLUSIONS: Passive knee flexion after TKA is significantly reduced when overstuffing the patellofemoral joint by +8 mm, and patellofemoral kinematics are altered when overstuffing the joint by +6 mm. These results demonstrate the relatively modest effects of patellofemoral overstuffing on knee flexion and patellar tracking kinematics after TKA.

Comparison of transposition techniques to reduce gap associated with high ulnar nerve lesions.

PURPOSE: To determine in a cadaveric model which of 3 anterior transposition techniques allows for maximum gap reduction for high ulnar nerve lesions. METHODS: Six fresh-frozen human adult upper extremity cadaveric transhumeral specimens were used. We anchored the ulnar nerve to bone 10 cm proximal and distal to the medial epicondyle along its exact course while keeping the elbow in 30° flexion as the baseline measurement. We then used a thick suture to mimic and measure the exact course of the nerve between the pins in varying elbow positions. The nerve was then transposed first subcutaneously, then intramuscularly, and then submuscularly while taking exact measurements of the distance the nerve had to travel in varying degrees of elbow flexion for each transposition method. We performed comparative analysis to analyze gap reduction with respect to transposition method and elbow position. RESULTS: Transposing the ulnar nerve reduced the repair gap required to cross the elbow regardless of transposition technique. When comparing individual techniques, however, the greatest gap reduction was achieved by intramuscular, followed by submuscular and finally subcutaneous transposition. A maximum gap reduction of 25 mm (average, 23 mm) was achieved using intramuscular transposition with the elbow in 90° flexion. Subcutaneous transposition actually increased the repair gap when the elbow was in an extended position. CONCLUSIONS: An intramuscular transposition with the elbow in 90° flexion provided the best gap reduction. However, post-neurorrhaphy mobilization may compromise repair site integrity and vascularity if elbow flexion is required to achieve a primary repair, and these factors should be considered carefully when planning treatment. CLINICAL RELEVANCE: This study provides guidance on techniques to reduce nerve gap for primary repair of the ulnar nerve at the elbow using transposition and elbow flexion.

Anterior intrapelvic migration of femoral trial head requiring secondary surgical approach for retrieval.

The current report describes a revision total hip arthroplasty in which the trial femoral head disassociated during reduction and migrated into a soft tissue capsule of the true pelvis between the external iliac vein and corona mortise. The authors believe this previously undescribed migration pattern was created by the patient's history of recurrent dislocations. To retrieve the trial prosthesis without injuring the adjacent vasculature, a secondary surgical approach was utilized. The described case identifies the risk of pelvic migration in patients with a history of dislocations and reminds us that a secondary surgical approach should be considered to avoid devastating injury to the neighboring vasculature.

Prevalence of Depressive Symptoms in Aseptic Revision Total Knee Arthroplasty Based on the Mode of Failure.

Background: Complications following total knee arthroplasty (TKA) that necessitate revision cause considerable psychological distress and symptoms of depression, which are linked to poorer postoperative outcomes, increased complications, and increased healthcare utilization. We aimed to identify the prevalence of mental health disorders and symptoms preoperatively and postoperatively in patients undergoing aseptic revision TKA and to stratify these patients based on their mechanism of failure. Methods: All patients undergoing aseptic revision TKA from 2008 to 2019 with a minimum 1-year follow-up were retrospectively reviewed at a single institution. Patients (n = 394) were grouped based on 7 failure modes previously described. Patients were considered to have depressive symptoms if their Veterans RAND-12 mental component score was below 42. Preoperative and postoperative Veterans RAND-12 mental component scores at the latest follow-up were evaluated. Results: Overall comparative prevalence of preoperative to postoperative depressive symptoms was 23.4%-18.8%. By mode of failure are as follows: arthrofibrosis (25.8%-16.7%), aseptic loosening (25.3%-18.9%), extensor mechanism disruption (25%-50%), failed unicompartmental knee arthroplasty (8.6%-14.3%), instability (25.7%-17.1%), osteolysis or polyethylene wear (23.1%-23.1%), and patellar failure (11.8%-23.5%). There was no difference in depressive symptoms among failure modes preoperatively (P = .376) or at the latest postoperative follow-up (P = .175). Conclusions: The prevalence of depressive symptoms in revision TKA patients appears to be independent of failure mode. Surgeon awareness and screening for depressive symptoms in this patient population preoperatively with referral for potential treatment may improve early postoperative outcomes.

Hemoglobinopathy is Associated With Total Hip Arthroplasty Indication Even Beyond Sickle Cell Anemia.

Background: The extent to which hemoglobinopathies other than sickle anemia (HbSS) are associated with hip osteonecrosis is unknown. Sickle cell trait (HbS), hemoglobin SC (HbSC), and sickle/ß-thalassemia (HbSßTh) may also predispose to osteonecrosis of the femoral head (ONFH). We sought to compare the distributions of indications for a total hip arthroplasty (THA) in patients with and without specific hemoglobinopathies. Methods: PearlDiver, an administrative claims database, was used to identify 384,401 patients aged 18 years or older undergoing a THA not for fracture from 2010 to 2020, with patients grouped by diagnosis code (HbSS N = 210, HbSC N = 196, HbSßTh N = 129, HbS N = 356). ß-Thalassemia minor (N = 142) acted as a negative control, and patients without hemoglobinopathy as a comparison group (N = 383,368). The proportion of patients with ONFH was compared to patients without it by hemoglobinopathy groups using chi-squared tests before and after matching on age, sex, Elixhauser Comorbidity Index, and tobacco use. Results: The proportion of patients with ONFH as the indication for THA was higher among those with HbSS (59%, P < .001), HbSC (80%, P < .001), HbSßTh (77%, P < .001), and HbS (19%, P < .001) but not with ß-thalassemia minor (9%, P = .6) than the proportion of patients without hemoglobinopathy (8%). After matching, the proportion of patients with ONFH remained higher among those with HbSS (59% vs 21%, P < .001), HbSC (80% vs 34%, P < .001), HbSßTh (77% vs 26%, P < .001), and HbS (19% vs 12%, P < .001). Conclusions: Hemoglobinopathies beyond sickle cell anemia were strongly associated with having osteonecrosis as the indication for THA. Further research is needed to confirm whether this modifies THA outcomes.