Faculty Bibliography

INTRODUCTION/BACKGROUND:While the learning curve for direct anterior approach (DAA) total hip arthroplasty (THA) is steep, no classification exists to predict technically challenging cases. We propose and validate a new Davidovitch direct anterior (DDA) classification system for predicting DAA THA case complexity. METHODS:We retrospectively reviewed primary DAA THAs by two fellowship-trained surgeons (October 2019 to June 2025). Exclusions included fracture, contralateral hardware, incomplete pelvis radiographs, or less than one year of follow-up. Cases were grouped into learning curve, proficient, and expert phases. Classification was based on preoperative antero-posterior (AP) pelvis radiographs. Operative time served as a proxy for case difficulty. Univariate and multivariate regressions assessed the effects of classification, surgeon experience, fixation method, and body mass index (BMI). RESULTS:Multivariate analyses of 283 cases, including DDA classification, surgeon experience, fixation method, and BMI, demonstrated that operative times were significantly longer for DDA 4 versus DDA 1 cases (P = 0.011). Operative time decreased across learning curve, proficient, and expert phases (P < 0.001). Higher BMI (P < 0.001) and cemented fixation (P = 0.004) independently increased operative time. There were 13 overall complications and two revision THAs within 90 days. CONCLUSION/CONCLUSIONS:This novel radiographic classification system predicted case difficulty in DAA THA, as DDA 4 cases took longer than DDA 1 cases, particularly during the learning curve. Beyond the learning curve, the impact of DDA classification on operative time diminished. This classification system has the potential to serve as a valuable preoperative tool for operative planning and workday efficiency, particularly for early-career surgeons on their learning curve.

INTRODUCTION/BACKGROUND:Periprosthetic patellar fracture (PPPF) after total knee arthroplasty (TKA) is a rare complication, but can significantly affect patient function and implant survival. This study sought to better identify radiographic and anatomical risk factors for PPPF compared to a propensity-matched cohort. METHODS:We retrospectively queried 22,092 TKAs from January 2011 to December 2024 with patellar resurfacing at a single, urban, academic institution, yielding 44 (0.2%) verified cases of PPPF after TKA. Using propensity score matching on the basis of age, sex, body mass index (BMI), race, and Charlson Comorbidity Index, 44 control TKA patients who had patellar resurfacing without fracture were identified and analyzed using the same methods. RESULTS:The mean time to PPPF was two years after TKA (range, 10 days to 10 years), and 46% were atraumatic. A decreased native lateral patellar tilt (20.0 versus 22.6°, P = 0.039) and thinner native patellar thickness (22.6 versus 24.0 mm, P = 0.018) were associated with increased PPPF risk. Lateralization of the patella during resurfacing also increased risk (P = 0.011), as well as increased patellar component size (P = 0.034). On Receiver Operating Characteristic analysis, thinner native patella thickness was the most predictive of fracture risk (Area Under the Curve = 0.621); however, this result was underpowered, thus an optimal cutoff value could not be meaningfully established. CONCLUSION/CONCLUSIONS:The PPPFs are rare complications following TKA and may occur with or without trauma. Native patellar thickness was inversely correlated with fracture risk, and lateral positioning during resurfacing and increased component size were associated with increased risk. Patients who had PPPFs also demonstrated lesser lateral patellar tilt compared to non-fractured controls. Further investigation with a larger cohort may enable more precise risk factor stratification.

BACKGROUND:The Coronal Plane Alignment of the Knee (CPAK) classification method describes knee phenotypes. The rise in robotic-assisted total knee arthroplasties (RA-TKA) has enabled surgeons to fine-tune bony cuts, minimizing soft tissue release while prioritizing balanced gaps rather than predetermined alignment targets, a technique known as functional alignment (FA). As a patient’s preoperative CPAK changes when using FA, our aim was to assess which preoperative CPAK phenotypes are maintained post-TKA and further define this change with a simplified classification. METHODS:We retrospectively reviewed 1,028 primary RA-TKA cases performed using functional alignment (FA) technique from 2023 to 2024. Arithmetic hip-knee-ankle (aHKA) and joint line obliquity (JLO) angles were obtained using robotic software, with boundaries in accordance with CPAK. Demographics, CPAK phenotypes, and planned resections were collected and analyzed. RESULTS: < 0.001). Based on results, we classified preoperative alignment according to final functional coronal alignment that would reflect tibia and aHKA angles and propose a new, simplified Functional Coronal Alignment (FCA) classification composing of four categories. CONCLUSION:This study highlighted the clinical usefulness of robotics for FA and described the FCA classification system to guide surgeons in optimizing kinematics using robotic assistance for FA.

BACKGROUND:Varying degrees of flexion contracture appear commonly in total knee arthroplasty (TKA) patients and can be corrected using increasing distal femoral bone resection. Robotic-assisted (RA) technology aims to avoid ligament release through optimized bony resections. This study evaluated the influence of preoperative flexion contracture on the magnitude of resections surgeons perform to balance knees in RA-TKA. MATERIALS AND METHODS/METHODS:We reviewed 789 primary RA-TKAs from 2023 to 2024 using cruciate-retaining (CR) implants. The cohort was divided by native flexion deformity into three groups: <0° flexion ("hyperextension", n = 157), 0-9.9° flexion ("minimal contracture", n = 457), and ≥ 10° flexion ("clinically important contracture", n = 175). Mean preoperative flexion contracture was - 3.8, 4.1, and 13.5° for the hyperextension, minimal contracture, and clinically important contracture cohorts, respectively. Demographics, implants, and intraoperative data were collected and analyzed. The arithmetic hip-knee-ankle (aHKA) angle was used to determine native deformity groups for additional subanalyses. RESULTS:Significant differences were found between cohorts for mean distal femur and proximal tibia resections, with the clinically important contracture group having the largest resections. After accounting for implanted polyethylene thickness, differences in mean tibia resections were quite small, varying by 0.9 millimeters (mm) laterally and 0.7 mm medially. Similarly, the mean distal femoral resection varied by only 1.4 mm laterally and 0.7 mm medially between the hyperextension and clinically important contracture cohorts. Indeed, 85% of cases with clinically important contractures were managed with less than 2 mm of additional distal femoral resection compared to the minimal contracture cohort. CONCLUSION/CONCLUSIONS:With robotic-assisted TKA, bone resections can be guided by collateral ligament tension in flexion and extension. Our data suggest that surgeons can follow this strategy and successfully address flexion contractures with very small increases in resection magnitudes, which may help to maintain the joint line.

BACKGROUND:Patients treated at a health safety-net hospital have increased medical complexity and social determinants of health that are associated with an increasing risk of complications after TKA and THA. Fast-track rapid recovery protocols (RRPs) are associated with reduced complications and length of stay in the general population; however, whether that is the case among patients who are socioeconomically disadvantaged in health safety-net hospitals remains poorly defined. QUESTIONS/PURPOSES/OBJECTIVE:When an RRP protocol is implemented in a health safety-net hospital after TKA and THA: (1) Was there an associated change in complications, specifically infection, symptomatic deep venous thromboembolism (DVT), symptomatic pulmonary embolism (PE), myocardial infarction (MI), and mortality? (2) Was there an associated difference in inpatient opioid consumption? (3) Was there an associated difference in length of stay and 90-day readmission rate? (4) Was there an associated difference in discharge disposition? METHODS:An observational study with a historical control group was conducted in an urban, academic, tertiary-care health safety-net hospital. Between May 2022 and April 2023, an RRP consistent with current guidelines was implemented for patients undergoing TKA or THA for arthritis. We considered all patients aged 18 to 90 years presenting for primary TKA and THA as eligible. Based on these criteria, 562 patients with TKAs or THAs were eligible. Of these 33% (183) were excluded because they were lost before 90 days of follow-up and had incomplete datasets, leaving 67% (379) for evaluation. Patients in the historical control group (September 2014 to May 2022) met the same criteria, and 2897 were eligible. Of these, 31% (904) were excluded because they were lost before 90 days of follow-up and had incomplete datasets, leaving 69% (1993) for evaluation. The mean age in the historical control group was 61 ± 10 years and 63 ± 10 years in the RRP group. Both groups were 36% (725 of 1993 and 137 of 379) men. In the historical control group, 39% (770 of 1993) of patients were Black and 33% (658 of 1993) were White, compared with 38% (142 of 379) and 32% (121 of 379) in the RRP group, respectively. English was the most-spoken primary language, by 69% (1370 of 1993) and 68% (256 of 379) of the historical and RRP groups, respectively. A total of 65% (245 of 379) of patients in the RRP group had a peripheral nerve block compared with 54% (1070 of 1993) in the historical control group, and 39% (147 of 379) of them received spinal anesthesia, compared with 31% (615 of 1993) in the historical control group. The main elements of the RRP were standardization of preoperative visits, nutritional management, neuraxial anesthesia, accelerated physical therapy, and pain management. The primary outcomes were the proportions of patients with 90-day complications and opioid consumption. The secondary outcomes were length of stay, 90-day readmission, and discharge disposition. A multivariate analysis adjusting for age, BMI, gender, race, American Society of Anaesthesiologists class, and anesthesia type was performed by a staff biostatistician using R statistical programming. RESULTS:After controlling for the confounding variables as noted, patients in the RRP group had fewer complications after TKA than those in the historical control group (odds ratio 2.0 [95% confidence interval 1.3 to 3.3]; p = 0.005), and there was a trend toward fewer complications in THA (OR 1.8 [95% CI 1.0 to 3.5]; p = 0.06), decreased opioid consumption during admission (517 versus 676 morphine milligram equivalents; p = 0.004), decreased 90-day readmission (TKA: OR 1.9 [95% CI 1.3 to 2.9]; p = 0.002; THA: OR 2.0 [95% CI 1.6 to 3.8]; p = 0.03), and increased proportions of discharge to home (TKA: OR 2.4 [95% CI 1.6 to 3.6]; p = 0.01; THA: OR 2.5 [95% CI 1.5 to 4.6]; p = 0.002). Patients in the RRP group had no difference in the mean length of stay (TKA: 3.2 ± 2.6 days versus 3.1 ± 2.0 days; p = 0.64; THA: 3.2 ± 2.6 days versus 2.8 ± 1.9 days; p = 0.33). CONCLUSION/CONCLUSIONS:Surgeons should consider developing an RRP in health safety-net hospitals. Such protocols emphasize preparing patients for surgery and supporting them through the acute recovery phase. There are possible benefits of neuraxial and nonopioid perioperative anesthesia, with emphasis on early mobility, which should be further characterized in comparative studies. Continued analysis of opioid use trends after discharge would be a future area of interest. Analysis of RRPs with expanded inclusion criteria should be undertaken to better understand the role of these protocols in patients who undergo revision TKA and THA. LEVEL OF EVIDENCE/METHODS:Level III, therapeutic study.

BACKGROUND/UNASSIGNED:Osteoporotic pelvic fractures in the elderly lead to pain and immobility resulting in decreased quality of life and worsening frailty. Teriparatide has been shown to shorten time to fracture union, diminish pain, and improve mobilization. At our hospital, this medication is prescribed by an outpatient endocrinologist or geriatrician. We hypothesize that elderly female patients sustaining low energy lateral compression (LC) pelvic fractures are not given Teriparatide. This study reports rates of successful Teriparatide initiation and looks for areas of improvement. MATERIALS AND METHODS/UNASSIGNED:A retrospective chart review of stable LC pelvic fractures admitted to a single urban academic level 1 trauma center from January 2012 to February 2021 was conducted. Females over 60 years old with stable LC pelvic fractures were included. Males and those aged less than 60 were excluded. RESULTS/UNASSIGNED:0.10). Insurance did not approve the medication in 2 instances and in 1 instance it was discontinued at follow-up. CONCLUSION/UNASSIGNED:Despite level 1 evidence of Teriparatide's benefit for elderly osteoporotic women with low energy LC pelvic fractures, we failed to initiate treatment in 93% of eligible patients. Barriers to initiation included low rates of medical evaluation for its use and failure of insurance coverage. There are opportunities for multidisciplinary collaboration to increase evaluation for and initiation of Teriparatide. LEVEL OF EVIDENCE/UNASSIGNED:Cohort Retrospective (level III evidence).

INTRODUCTION/BACKGROUND:Hip resurfacing arthroplasty (HRA) is a surgical option with positive outcomes at medium-term follow-up for young, active patients with osteoarthritis. However, early failures of HRA often occur due to improper implant placement. The purpose of this study was to assess the utility of computer-assisted navigation in the effort to optimize implant positioning following HRA. MATERIALS AND METHODS/METHODS:A retrospective analysis of 262 consecutive HRAs at a single institution was performed. Radiographic analysis included measurements of cup inclination and anteversion, leg length restoration (LLR), and offset. Cup position was evaluated based on placement within Lewinnek parameters and the surgeon's preferred anteversion (10° to 20°). Chi-squared and unpaired Student's t-test were performed for all categorical and continuous variables, respectively. RESULTS:One hundred fifty-six cases were performed using conventional technique and 106 cases used computernavigation. Computer-assisted HRA (caHRA) had a longer mean surgical time (129 vs. 110 minutes; p < 0.001) but shorter average LOS (1.1 vs. 1.5 days; p < 0.001). Cup position was within the surgeon-preferred target zone in 47% of caHRA versus 22% of conventional HRA (p = 0.0001). Cup position fell within the Lewinnek safe zone in 86% of caHRA versus 60% of conventional HRA (p < 0.001). Global offset was reduced by a mean of 6.4 mm in caHRA versus 8.4 mm (p = 0.036). No differences in rates of complication (p = 0.406), reoperation (p = 1.00), or 90-day readmission (p = 0.568) were observed. CONCLUSION/CONCLUSIONS:Computer-assisted technology in HRA allows for comparable clinical outcomes to conventional technique. Cup position accuracy and precision is improved by computer navigation in HRA.

BACKGROUND:Periacetabular osteotomy (PAO) has been used as a treatment modality for development dysplasia of the hip (DDH). Many patients will progress to total hip arthroplasty (THA) following PAO. There is a discrepancy in the literature regarding outcomes of THA after PAO. METHODS:A retrospective study was performed. Ten pa- tients (12 hips) with prior PAO who progressed to THA with at least 1-year follow-up after THA were identified. A control group of patients matched for age, sex, and body mass index (BMI) who underwent primary THA with minimum of 1-year follow-up were included. Demographic and radiographic parameters as well as clinical outcomes using the modified Harris Hip Score (mHHS) were collected. RESULTS:The mean age at the time of THA was 36.2 ± 9.7 years for the PAO and 37.8 ± 9.1 years for the control cohorts. There was no difference in the demographics be- tween the groups. At mean follow-up time of 22.8 ± 10.7 months for the PAO group and 25 ± 13.8 months for the control group, there was no significant difference in mHHS following THA. There was significant improvement in mHHS from preoperative to postoperative levels (p < 0.01). CONCLUSION/CONCLUSIONS:Total hip arthroplasty is an effective means to restore quality of life and function in patients who develop osteoarthritis following PAO, with equivalent outcomes to those undergoing primary THA.