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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.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).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.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.Economic and decision analysis, Level III.

Postoperative urinary retention (POUR) is a disruptive complication after modern rapid recovery total joint arthroplasty. This review aims to synthesize the recent literature on POUR in the setting of total joint arthroplasty. The incidence of POUR ranges from 5.5% to 46.3%. The lack of a standardized definition of POUR accounts for some of this variability. Risk factors previously associated with the development of POUR include increasing age, male sex, benign prostatic hyperplasia, use of bupivacaine and intrathecal morphine in spinal anesthesia, glycopyrrolate, and volume of intraoperative intravenous fluid administered. Predictive scoring assessments, such as the International Prostate Symptom Score and a newer predictive nomogram, have not been adequately validated by high-quality studies. The treatment of POUR comprises either intermittent or indwelling urethral catheterization. Higher quality prospective studies are needed to allow for the standardization of all aspects of POUR from its diagnostic criteria to its treatment.

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).

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.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 as400cc 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.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.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.

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 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.

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.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.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 RLL2 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.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.

Aims Cross-table lateral (CTL) radiographs are commonly used to measure acetabular component anteversion after total hip arthroplasty (THA). The CTL measurements may differ by > 10° from CT scan measurements but the reasons for this discrepancy are poorly understood. Anteversion measurements from CTL radiographs and CT scans are compared to identify spinopelvic parameters predictive of inaccuracy. Methods THA patients (n = 47; 27 males, 20 females; mean age 62.9 years (SD 6.95)) with preoperative spinopelvic mobility, radiological analysis, and postoperative CT scans were retrospectively reviewed. Acetabular component anteversion was measured on postoperative CTL radiographs and CT scans using 3D reconstructions of the pelvis. Two cohorts were identified based on a CTL-CT error of ≥ 10° (n = 11) or < 10° (n = 36). Spinopelvic mobility parameters were compared using independent-samples t-tests. Correlation between error and mobility parameters were assessed with Pearson’s coefficient. Results Patients with CTL error > 10° (10° to 14°) had stiffer lumbar spines with less mean lumbar flexion (38.9°(SD 11.6°) vs 47.4° (SD 13.1°); p = 0.030), different sagittal balance measured by pelvic incidence-lumbar lordosis mismatch (5.9° (SD 18.8°) vs -1.7° (SD 9.8°); p = 0.042), more pelvic extension when seated (pelvic tilt -9.7° (SD 14.1°) vs -2.2° (SD 13.2°); p = 0.050), and greater change in pelvic tilt between supine and seated positions (12.6° (SD 12.1°) vs 4.7° (SD 12.5°); p = 0.036). The CTL measurement error showed a positive correlation with increased CTL anteversion ( r = 0.5; p = 0.001), standing lordosis ( r = 0.23; p = 0.050), seated lordosis ( r = 0.4; p = 0.009), and pelvic tilt change between supine and step-up positions ( r = 0.34; p = 0.010). Conclusion Differences in spinopelvic mobility may explain the variability of acetabular anteversion measurements made on CTL radiographs. Patients with stiff spines and increased compensatory pelvic movement have less accurate measurements on CTL radiographs. Flexion of the contralateral hip is required to obtain clear CTL radiographs. In patients with lumbar stiffness, this movement may extend the pelvis and increase anteversion of the acetabulum on CTL views. Reliable analysis of acetabular component anteversion in this patient population may require advanced imaging with a CT scan. Cite this article: Bone Joint J 2021;103-B(7 Supple B):59–65.

It is known that chondrocytes from joints with osteoarthritis (OA) exhibit high levels of DNA damage, but the degree to which chondrocytes accumulate DNA damage during "normal aging" has not been established. The goal of this study was to quantify the DNA damage present in chondrocytes obtained from cadaveric donors of a wide age range, and to compare the extent of this damage to OA chondrocytes. The alkaline comet assay was used to measure the DNA damage in normal cartilage from the ankle (talus) and the knee (femur) of cadaveric donors, as well as in OA chondrocytes obtained at the time of total knee replacement. Chondrocytes from younger donors (45 years) had less DNA damage than older donors (70 years) as assessed by the percentage of DNA in the comet "tail". In donors between 50 and 60 years old, there was increased DNA damage in chondrocytes from OA cartilage as compared to cadaveric. Talar chondrocytes from 23 donors between the ages of 34 and 78 revealed a linear increase in DNA damage with age (R

Decellularized tendon xenografts offer a promising alternative for reconstruction by using ubiquitously available material. This study compares static and centrifugal seeding of avian tendon scaffolds with NIH 3T3 fibroblasts. Incorporation of viable cells was achievable with both techniques, represented by DNA content. Proliferation rate and viability assay showed neither damage by centrifugal force nor superiority of the technique. Cell proliferation after 10 days of culture demonstrated that the scaffold did not hinder 3-D culturing. Confocal laser microscopy revealed structural details as formation of focal adhesions, to provide deeper insight into the process of cell attachment and growth in xenografts.

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.

Secondary femoral fractures after the successful plate-screw fixation of a primary Vancouver type B1 periprosthetic femoral fracture (PFF) have been associated with the altered state of stress/strain in the femur as the result of plating. The laterally implanted condyle-spanning plate-screw constructs have shown promises clinically in avoiding secondary bone and implant failures as compared with shorter diaphyseal plates. Though the condyle-spanning plating has been hypothesized to avoid stress concentration in the femoral diaphysis through increasing the working length of the plate, biomechanical evidence is lacking on how plate length may impact the stress/strain state of the implanted femur. Through developing and experimentally validating finite element (FE) models of 3 cadaveric femurs, this study investigated the impact of plating on bone strains, load transfer and local stiffness, which were compared between FE models of 2 different plating systems that each had a diaphyseal configuration and a condyle-spanning configuration. Under simulated gait-loading, the condyle-spanning constructs of both plating systems were shown to lower the bone strains around the distal fixation screws (up to 24.8% reduction in maximum principal strain and 26.6% reduction in minimum principal strain) and in the distal metaphyseal shaft of the femur (up to 15.9% and 25.7% reductions in maximum and minimum principal strains, respectively), where secondary bone fractures have been typically reported. In the distal diaphyseal and metaphyseal shaft of femur, FE models of the condyle-spanning constructs were shown to increase the local compressive stiffness (up to 152.9% increases under simulated gait-loading) and decrease the transfer of compressive load (37.1% decreases under simulated gait-loading), which may be indicative of the lowered risks of bone damage.

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.

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.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.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.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.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.

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.

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.

1.AbstractBone grafting is the second most common tissue transplantation procedure worldwide. The gold standard for bone grafting is the autograft; however, due to morbidity and limited supply, new alternatives, including allograft and tissue-engineered bone substitutes, are needed to satisfy long-term demand. One of the most desired properties 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 treated porcine bone with a decellularization protocol to produce a bone scaffold. We examined whether the scaffold possessed osteoinductive potential and could be used to create a tissue-engineered bone microenvironment. To test if the bone scaffold was a viable host, pre-osteoblasts were seeded, incubated in vitro, and analyzed for markers of osteogenic differentiation. To assess these properties in vivo, scaffolds with and without pre-osteoblasts pre-seeded were subcutaneously implanted in mice for four weeks. The scaffolds underwent micro-computed tomography (microCT) scanning before implantation. After retrieval, the scaffolds were analyzed for osteogenic differentiation or re-scanned by microCT to assess new bone formation with the subsequent histological assessment. The osteoinductive potential was observed in vitro with similar osteogenic markers being expressed as observed in demineralized bone matrix and significantly greater expression of these markers than controls. By microCT, paired t-tests demonstrated significantly increased bone volume:total volume (BV/TV) and trabecular thickness (Tb.Th) after explantation in all groups. Pentachrome staining demonstrated osteogenesis within the scaffold, and angiogenesis in the scaffold was confirmed by CD31 staining for blood vessels. These results demonstrate that porcine bone maintains its osteoinductive properties after the application of a novel decellularization and oxidation protocol. 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, orthopaedic reconstruction, and could be used in the research of multiple diseases.

Introduction15%-20% of patients presenting for total hip arthroplasty (THA) have bilateral disease. While simultaneous bilateral THA is of interest to patients and surgeons, debate persists regarding its merits. The majority of previous reports on simultaneous bilateral THA involve patients in the lateral decubitus position, which require repositioning, prepping and draping, and exposure of a fresh wound to pressure and manipulation for the contralateral THA. The purpose of this study was to compare complications, component position, and financial parameters for simultaneous versus staged bilateral THAs using the direct anterior approach (DAA).MethodsMedical records were reviewed for patient demographics, medical history, operative time, estimated blood loss (EBL), change in hemoglobin, transfusion, tranexamic acid (TXA) use, length of stay (LOS), discharge disposition, leg length discrepancy, acetabular cup position, and perioperative complications. Cost and reimbursement data were analysed.Results44 patients were included in the sequential group and fifteen patients in the simultaneous group. Operative time, EBL, hemoglobin drop, transfusion rate, and LOS were significantly increased for simultaneous group. There was no significant difference in component position, complications, or readmissions between groups. Profit per hip was significantly higher for the simultaneous group.DiscussionWhile simultaneous DAA THA presents challenges, our results suggest that simultaneous DAA THA may add value to the healthcare system without resulting in increased complications compared to sequential hip arthroplasty.

Introduction: Hip fractures are common in the elderly patients with an incidence of 320 000 fractures/year in the United States, representing a health-care cost of US$9 to 20 billion. Hip fracture incidence is projected to increase dramatically. Hospitals must modify clinical models to accommodate this growing burden. Comanagement strategies are reported in the literature, but few have addressed orthopedic-hospitalist models. An orthopedic-hospitalist comanagement (OHC) service was established at our hospital to manage hip fracture patients. We sought to determine whether the OHC (1) improves the efficiency of hip fracture management as measured by inpatient length of stay (LOS) and time to surgery (TTS) and (2) whether our results are comparable to those reported in hip fracture comanagement literature. Methods: A comparative retrospective–prospective cohort study of patients older than 60 years with an admitting diagnosis of hip fracture was conducted to compare inpatient LOS and TTS for hip fracture patients admitted 10 months before (n = 45) and 10 months after implementation (n = 54) of the OHC at a single academic hospital. Secondary outcome measures included percentage of patients taken to surgery within 24 or 48 hours, 30-day readmission rates, and mortality. Outcomes were compared to comanagement study results published in MEDLINE-indexed journals. Results: Patient cohort demographics and comorbidities were similar. Inpatient LOS was reduced by 1.6 days after implementation of the OHC ( P = .01) without an increase in 30-day readmission rates or mortality. Time to surgery was insignificantly reduced from 27.4 to 21.9 hours ( P = .27) and surgery within 48 hours increased from 86% to 96% ( P = .15). Discussion: The OHC has improved efficiency of hip fracture management as judged by significant reductions in LOS with a trend toward reduced TTS at our institution. Conclusion: Orthopedic-hospitalist comanagement may represent an effective strategy to improve hip fracture management in the setting of a rapidly expanding patient population.

Background: Bone grafts are used in approximately one half of all musculoskeletal surgeries. Autograft bone is the historic gold standard but is limited in supply and its harvest imparts significant morbidity to the patient. Alternative sources of bone graft include allografts, synthetics and, less commonly, xenografts which are taken from animal species. Xenografts are available in unlimited supply from healthy animal donors with controlled biology, avoiding the risk of human disease transmission, and may satisfy current demand for bone graft products. Methods: In the current study, cancellous bone was harvested from porcine femurs and subjected to a novel decellularization protocol to derive a bone scaffold. Results: The scaffold was devoid of donor cellular material on histology and DNA sampling (p &lt, 0.01). Microarchitectural properties important for osteoconductive potential were preserved after decellularization as shown by high resolution imaging modalities. Proteomics data demonstrated similar profiles when comparing the porcine bone scaffold against commercially available human demineralized bone matrix approved for clinical use. Conclusion: We are unaware of any porcine-derived bone graft products currently used in orthopaedic surgery practice. Results from the current study suggest that porcine-derived bone scaffolds warrant further consideration to serve as a potential bone graft substitute.

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 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. 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). 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.

Unicompartmental knee arthroplasty (UKA) for end-stage degenerative disease of the knee limited to one compartment is a viable alternative to total knee arthroplasty (TKA). UKA necessitates less bone resection and tissue disruption, reduces blood loss, and preserves cruciate ligaments. UKA can be performed in either of the 3 knee compartments with medial compartment the most common. Lateral compartment UKA is a technically difficult surgery, but robotic systems can mitigate the difficulty for surgeons. Recently, robot-assisted systems have become available for UKA that have been shown to improve accuracy of component placement and allow for intraoperative real-time dynamic ligament balancing. A 3-dimensional model of the patient’s anatomy is created from a preoperative computed tomography scan of the patient’s knee, which is mapped to anatomical landmarks registered intraoperatively. Components are then placed for an operative resection plan. The robot-assisted system provides haptic feedback to the surgeon during bone resection, including an alert, should the high-speed burr leave the preplanned resection area. Postoperative measures have shown superior accuracy of component accuracy with robotic systems compared with conventional UKA surgical techniques. Currently, short-term and midterm clinical outcomes of robot-assisted UKA are available that appear similar to those of conventional UKA.

All-polyethylene and metal-backed tibial components are available for unicompartmental knee arthroplasty. Although the early design of all-polyethylene component was largely replaced by metal-backed components, improvements in polyethylene wear characteristics, component design, and surgical technique have renewed interest in all-polyethylene (InLay) components. In comparison with metal-backed (OnLay) designs, InLays require less bone resection and are easier to revise total knee replacements. Early aseptic loosening, tibial component subsidence, and anterior knee pain were found to be the primary contributors to failure of InLay designs. Controversy remains whether InLay or OnLay components are preferable for unicompartmental knee arthroplasty. Despite the component design, proper component alignment, cementation technique, and ligamentous balance remain crucial for implant survival and are highlighted in this article along with a comparison of InLay and OnLay results.

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. 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. 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. 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.

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.

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.

Introduction Arthroscopy is one of the most challenging surgical skills to assess and teach. Although basic psychomotor arthroscopic skills, such as triangulation and object manipulation, are incorporated into many simulation exercises, they are not always individually taught or objectively evaluated. In addition, arthroscopic instruments, arthroscopy cameras, and the cadaver or joint models necessary for practice are costly. Methods A low-cost arthroscopic simulator was created to practice triangulation, probing, horizon changes, suture management, and object manipulation. The simulator materials were purchased exclusively from national hardware stores with a total cost averaging $79. The universal serial bus (USB) camera is included in the total cost. Three residency programs accredited by the Accreditation Council for Graduate Medical Education were tested on the simulator. Replica boards were created at each institution. Participants included medical students (20), residents (46), and attending physicians (9). Results Construct validity-the ability to differentiate between novice, intermediate, and senior level participants-was obtained. On all tasks, junior residents scored at a statistically significant lower rate than senior residents and attending physicians. Conclusions This cost-effective arthroscopic surgical simulator objectively demonstrated that attending physicians and senior residents performed at a higher level than junior residents and novice medical students. The results of this study demonstrate that this simulator could be an important training tool for resident education.

Background: Radiation-induced fibrosis (RIF) of musculoskeletal tissue is a common complication of radiation therapy for extremity soft-tissue sarcoma, with no standardized strategy for prevention and treatment. Angiotensin-(1-7) (Ang-[1-7]), a well-tolerated endogenous heptapeptide hormone with antitumor and antifibrotic properties, was tested as a radioprotectant for RIF and stiffening of irradiated muscles. Methods: Male CD-1 mice were randomized to one of three treatment groups: control, simulated sarcoma radiation therapy to the gastrocnemius and soleus muscles, or radiation therapy along with continuous Ang-(1-7) delivery initiated three days before radiation therapy. The biologically equivalent dose of radiation (∼100.3 Gy) absorbed by normal musculature during the course of radiation therapy for extremity sarcoma was delivered by means of four dose fractions of 7.3 Gy over two weeks. Fibrosis (n = 5 per group) and mechanical properties (n = 4 to 6 per group) of the muscles were measured at six weeks and four months after radiation therapy, and the intramuscular concentration of the profibrotic cytokines transforming growth factor-beta (TGF-β) and connective tissue growth factor (CTGF) (n = 8 to 10 per group) were measured at six weeks. Results: Interstitial (p < 0.01) and perivascular (p < 0.05) fibrosis increased significantly in the muscles treated with radiation therapy alone versus the nonirradiated controls at both six weeks (interstitial, +89%; perivascular, +112%) and four months (interstitial, +154%; perivascular, +88%). The muscles treated with radiation alone also exhibited increased tension (p < 0.01) versus nonirradiated controls at both six weeks (+779%) and four months (+1761%) when placed under 5% strain, and at four months (+1390%; p < 0.001) under 10% strain. At four months, muscle stiffness had increased in the mice treated with radiation therapy alone (+90%; p = 0.002) compared with nonirradiated controls. TGF-β production was also greater in this group at six weeks (+37%; p = 0.06) versus control. Ang-(1-7) administration prevented RIF and stiffening, with no differences observed for any other outcome between those receiving radiation therapy with Ang-(1-7) and the nonirradiated controls. Likewise, Ang-(1-7) mitigated the increase in TGF-β and CTGF concentration from radiation therapy. Conclusions: Ang-(1-7) attenuated RIF, stiffening, and production of profibrotic cytokines that were elevated in mouse skeletal muscles after simulated radiation therapy for extremity sarcoma. Clinical Relevance: Ang-(1-7) may serve as a potential therapy for the prevention of RIF in patients who require radiation therapy as adjuvant treatment for soft-tissue sarcoma.

Background: Psychomotor testing has been recently incorporated into residency training programs not only to objectively assess a surgeon’s abilities but also to address current patient-safety advocacy and medicolegal trends. The purpose of this study was to develop and test a cost-effective psychomotor training and assessment tool—The Fundamentals of Orthopaedic Surgery (FORS)—for junior-level orthopaedic surgery resident education. Methods: An orthopaedic skills board was made from supplies purchased at a local hardware store with a total cost of less than $350 so as to assess six different psychomotor skills. The six skills included fracture reduction, three-dimensional drill accuracy, simulated fluoroscopy-guided drill accuracy, depth-of-plunge minimization, drill-by-feel accuracy, and suture speed and quality. Medical students, residents, and attending physicians from three orthopaedic surgery residency programs accredited by the Accreditation Council for Graduate Medical Education participated in the study. Twenty-five medical students were retained for longitudinal training and testing for four weeks. Each training session involved an initial examination followed by thirty minutes of board training. The time to perform each task was measured with accuracy measurements for the appropriate tasks. Statistical analysis was done with one-way analysis of variance, with significance set at p < 0.05. Results: Forty-seven medical students, twenty-nine attending physicians, and fifty-eight orthopaedic surgery residents participated in the study. Stratification among medical students, junior residents, and senior residents and/or attending physicians was found in all tasks. The twenty-five medical students who were retained for longitudinal training improved significantly above junior resident level in four of the six tasks. Conclusions: The FORS is an effective simulator of basic motor skills that translates across a wide variety of operations and has the potential to advance junior-level participants to senior resident skill level. Clinical Relevance: The FORS simulator may serve as a valuable tool for resident education.

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. 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. 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). 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. IV.

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.

This study sought to determine whether templating for metal-on-metal hip resurfacing is more accurate with digital or acetate methodology. The medical records of 102 consecutive patients who underwent hip resurfacing at our institution were retrospectively reviewed. Records lacking preoperative radiographs that included a magnification-establishing marker were excluded, leaving 78 records for study. Two investigators independently prepared acetate and digital templates of the preoperative radiographs, which had been calibrated to 120% magnification, to predict femoral and acetabular component size. Accuracy was measured by comparing the predicted component sizes to the surgically implanted component sizes. Digital templating was more accurate than acetate templating in predicting hip resurfacing component size when measuring accuracy of templates by the absolute error of predicted component sizes (femoral, P.001; acetabular, P = .002), and by the prediction of components to +/-1 size difference (femoral, P = .001; acetabular, P = .002). Experience of the templating surgeon did not correlate with templating accuracy for acetate or digital templating. Although acetate templating is often regarded as the "gold standard" in preoperative planning, data from the current study shows that digital technology can be used for accurate preoperative templating prior to hip resurfacing procedures.