Faculty Bibliography

BACKGROUND:This study evaluated differences in surgical and clinical outcomes among patients who have identical versus different implant sizes in sequential total knee arthroplasty (TKA) surgeries. METHODS:We retrospectively reviewed patients who underwent primary, elective, staged, bilateral, same-surgeon, same-prosthesis TKA between 2011 and 2024 at a large academic health system. Patients were grouped by femoral and tibial implant size consistency: same femoral and tibial (SS), different femoral, same tibial, different tibial, same femoral, and different femoral and tibial (DD). RESULTS:A total of 4,536 TKAs were performed in 2,268 patients. The SS had the shortest length of stay compared to DD (51.8 versus 58.2 hours, P < 0.001). The majority had the same femoral (75.6%) and tibial (76.6%) sizes in both knees, whereas polyethylene thickness varied. Undergoing contralateral surgery within one year was associated with receiving the same implant sizes (P < 0.001). The DD were more common in manual surgery, and the SS were more common using navigation assistance (P < 0.001). Different assistance modalities between surgeries increased different femoral, same tibial and DD, whereas the same navigation assistance increased SS (P < 0.001). Complication and revision rates were not significantly different between the groups. All groups showed improvement in their Knee injury and Osteoarthritis Outcome Score for Joint Replacement and Patient-Reported Outcomes Measurement Information System Pain Intensity and Interference scores with no significant intergroup differences (P > 0.05). CONCLUSIONS:Over one-third of patients (37.3%) undergoing staged, bilateral TKA received different implant sizes for at least one component, and over half had different polyethylene thicknesses. Although implant size consistency was influenced by factors such as time between surgeries and assistance modality, these variations did not significantly affect length of stay, complications, or patient-reported outcomes. Surgeons should be aware that minor implant size differences between knees are common, even when using the same prosthesis.

BACKGROUND:Patients with chronic kidney disease (CKD) and dialysis dependence represent high-risk populations with increased demand for total joint arthroplasty (TJA). We aimed to assess surgical outcomes of CKD and dialysis-dependent (DD) patients undergoing TJA. METHODS:A multicenter retrospective review of TJA records between June 2011 and July 2022 was conducted. Patients with a diagnosis of CKD who were DD at the time of surgery were propensity-matched to non-DD CKD patients and control subjects without CKD in a ratio of 1:5:5. Matched comparisons and Kaplan-Meier survival analyses were conducted for a total of 176 (DD: 16) total knee arthroplasty (TKA) and 297 (DD: 27) total hip arthroplasty (THA) patients. RESULTS:Medical complications within 90 days after both TKA (control: n = 1, 1.3%; CKD: n = 3, 3.8%; DD: n = 3, 18.8%; P = 0.005) and THA (control: n = 4, 3%; CKD: n = 4, 3%; DD: n = 6, 22.2%; P < 0.001) were significantly higher in the DD group. Infection and revision rates at last follow-up were similar between the three groups after TKA (P > 0.05) and THA (P > 0.05). In Kaplan-Meier analyses, survivorship free of mortality was lowest in the DD group after THA at 40.3% compared with 100% in the control and 78.8% in the CKD groups (P < 0.001). CONCLUSION/CONCLUSIONS:Dialysis-dependent patients are at an increased risk of postoperative medical complications and mortality compared with matched groups with and without CKD. Infection and revision rates seem to be similar. We advocate for a shared decision-making approach between patient and surgeon to include a thorough discussion weighing postoperative complication risk, patient function, and life expectancy. LEVEL OF EVIDENCE/METHODS:III.

BACKGROUND:Robotic-assisted total joint arthroplasty (RTJA) is increasingly used to improve patient outcomes and reduce revision rates in total joint arthroplasty (TJA). With robotic-assisted total knee arthroplasty (RTKA) projected to exceed 70% of cases by 2030, concern exists about whether orthopaedic residents are being adequately trained. METHODS:Orthopaedic arthroplasty fellows between 2023 and 2025 completed an anonymous electronic survey assessing exposure to RTJA and conventional TJA (CTJA), impact on fellowship selection, and projected future use. Incomplete responses and non-fellows were excluded. RESULTS:Of 60 respondents, 78% were exposed to RTKA, 52% to robotic-assisted unicompartmental knee arthroplasty (RUKA), and 48% to robotic-assisted total hip arthroplasty (RTHA). Satisfaction with training was higher for conventional procedures: 82 versus 53% (TKA), 97 versus 32% (THA), and 23 versus 31% (UKA). Most felt comfortable performing conventional TKA (CTKA) and THA (CTHA) independently; among robotic procedures, only RTKA had similar comfort levels. Fellowship selection was influenced by a desire for balanced robotic and manual experience (66.7%). While 42% did not believe robotics should be required in residency, most agreed it improved understanding and performance (68% RTKA, 61% RUKA, and 75% RTHA respondents). Robotic exposure during residency was associated with higher satisfaction and preparedness (P < 0.001) and increased support for requiring training in RUKA (P = 0.015) and RTHA (P = 0.006). Regional differences in exposure and satisfaction were also observed. Fellows planning to use robotics in greater than 50% of future cases were more likely to choose robotics-focused fellowships (P = 0.003). CONCLUSION/CONCLUSIONS:Arthroplasty fellows reported high satisfaction with conventional arthroplasty training, whereas satisfaction and self-reported preparedness for robotic-assisted procedures were lower. Prior robotic exposure during residency was associated with higher satisfaction and preparedness, and fellows expressed interest in balanced robotic and manual fellowship experiences. These findings provided a baseline of current trainee perceptions.

BACKGROUND:Simultaneous bilateral total knee arthroplasty (BTKA) is avoided due to higher perioperative risk, favoring staged procedures. This study evaluated how the interval between staged TKAs affects patient-reported outcome measures (PROMs) and compared complications between the first and second procedures. METHODS:We retrospectively reviewed patients undergoing primary, elective, staged, BTKAs at a high-volume academic center between 2011 and 2024. Intra- and perioperative data and complications were compared between the surgeries. Patients were stratified by interval: less than three months ("extremely short waiters"), three to six months, six to nine months, nine to 12 months, one to two years, two to five years, and greater than five years. The PROMs were compared across these groups. A total of 4,210 patients underwent 8,420 staged, BTKAs at a mean 21.4-month interval. The most common intervals were six to nine months (27.4%) and nine to 12 months (21.1%). RESULTS:Patients were more likely to return to the emergency department (22 versus 16, P = 0.030) and be readmitted (48 versus 26, P = 0.113) after the second surgery, primarily due to infection. Revision rates did not differ. "Extremely short waiters" had the greatest improvement in Patient-Reported Outcomes Measurements Information System Pain Intensity and interference scores nine months after the second TKA (change 13.4 and 15.1, P < 0.001). At three months following the second surgery, those who waited three to six months had the largest Knee Injury and Osteoarthritis Outcome Score for Joint Replacement score improvement (change 23.7, P = 0.004). At one year after the second surgery, "extremely short waiters" again showed the greatest reduction in Patient-Reported Outcomes Measurements Information System Pain Intensity (change 10.5, P = 0.007) and Interference (change 11.3, P < 0.001). CONCLUSIONS:The interval between surgeries significantly impacted PROMs, with shorter intervals associated with better pain relief and functional recovery. Surgical timing should be tailored to individual patient goals and recovery trajectories.

INTRODUCTION/BACKGROUND:Reported average total joint arthroplasty (TJA) volumes among orthopaedic surgeons in the United States range from 22 to 65 cases per year. However, this figure is heavily influenced by a large cohort of ultra-low-volume surgeons who perform fewer than 10 TJAs annually, representing a relatively small number of patients. This study reassessed surgeon volume trends by taking ultra-low-volume surgeons into account while also quantifying the average caseload of a typical TJA patient's surgeon. METHODS:A national insurer database was used to identify all patients who underwent primary total knee arthroplasty (TKA) and total hip arthroplasty (THA) from 2016 to 2023. Surgeon volume was defined as the number of TJAs performed in a calendar year. Surgeons were categorized as standard-volume (≥ 10 cases/year) or ultra-low-volume (< 10 cases/year). Descriptive statistics were used to characterize trends before and after excluding ultra-low-volume surgeons. The average caseload of a typical TJA patient's surgeon was calculated by averaging surgeon volume on a patient-by-patient basis. RESULTS:Between 2016 and 2023, mean case volume increased from 35.5 to 37.7 while the median decreased from six to four. The percentage of ultra-low-volume surgeons (< 10 cases) increased from 57.0% of all surgeons in 2016 to 60.0% in 2023, accounting for only 4.1% of all cases in 2016 and 3.8% in 2023. Standard-volume surgeons accounted for 95.9% of all cases in 2016 and 96.2% in 2023. After including only standard-volume surgeons, the mean number of cases per year increased from 79.1 to 90.7, and the median increased from 44 to 53. Moreover, the average patient undergoing TJA was treated by a surgeon whose annual caseload increased from 188.7 to 192.8. DISCUSSION/CONCLUSIONS:Annual case volume averages are heavily skewed by ultra-low-volume surgeons, obscuring an increase in the number of cases performed by standard joint arthroplasty surgeons. The typical TJA patient is treated by a high-volume surgeon whose caseload has increased from 2016 to 2023.

While there have been great advancements in total knee arthroplasty (TKA) over the past 50 years, anterior knee pain (AKP) remains the most common concern among patients postoperatively. Despite exhausting evidence supporting no clinical difference in AKP with resurfaced vs. unresurfaced patellae in TKA, 87% of TKAs are resurfaced in the United States, compared with 2% in other countries. These large practice variations underscore a lack of consensus regarding the role of the patella and the approach to the anterior compartment of the knee in TKA. The aim of this review was to go beyond patellar resurfacing and describe the effects that surgical technique and implant design may have on AKP in current TKA.

BACKGROUND:Modern polyethylene allows larger bearings in fixed-bearing total hip arthroplasty (THA), but any stability benefits of fully maximizing bearing diameter (e.g., 36-millimeter (mm) in 48/50-mm cups) are not well-established. We hypothesized that maximizing bearing diameter reduces odds of dislocation in primary fixed-bearing THA. METHODS:We retrospectively reviewed all patients who underwent fixed-bearing THA at a large, urban, academic institution between 2016 and 2022. We noted cases receiving the largest bearing available from any manufacturer for the acetabular diameter: 28 mm in 40/42 mm, 32 mm in 44/46-, 36- in 48/50-, or 40- in 52/54/56 mm. Larger cups were excluded because proportionately larger bearings were unavailable. Multivariate analyses using least-absolute-shrinkage-and-selection-operator (LASSO) logistic regression were performed to explore the association between maximized bearing diameter and dislocation risk while controlling for confounders. RESULTS:Bearing diameter was maximized in 835 (9.8%) of 8,607 patients, whereas 7,309 (84.9%) received the second-largest bearing available. There were 79 dislocations (0.9% overall); none occurred with maximized bearing diameters (P = 0.003). On univariate analyses, dislocation risk also varied with intraoperative technology use, surgical approach, and liner geometry (P = 0.017, P = 0.008, P = 0.007, respectively). In LASSO regression including these variables, maximized bearing diameters heavily protected against dislocation (odds ratio (OR) = 0.14). Robotic surgery (OR = 0.35), computer-navigation (OR = 0.90), lateral (OR = 0.48), and anterior (OR = 0.62) approaches were also protective. Lipped (OR = 1.2) and offset (OR = 1.4) liners, commonly used with posterior approaches and non-maximized bearing diameters, were associated with slightly higher odds of dislocation. Subanalysis of 4,185 patients who underwent posterior approach THA using non-maximized bearings revealed that liner geometry did not impact dislocation odds within this subgroup. CONCLUSION/CONCLUSIONS:Fully maximizing bearing diameter markedly reduced dislocation odds in primary fixed-bearing THA. The magnitude of this effect was substantially larger compared to other variables under surgeon control.

INTRODUCTION/BACKGROUND:This multicenter randomized controlled trial (RCT) sought to determine if dual-mobility bearings (DM) reduce dislocations in patients at high-risk for instability undergoing primary total hip arthroplasty (THA) compared to single bearing (SB) femoral heads. METHODS:A total of 555 patients undergoing primary posterior approach THA were randomized to DM (n = 271; 42 mm mean effective head, range 36 to 55) or SB heads (n = 284; 28 mm [n = 2], 32 mm [n = 42], 36 mm [n = 168], 40 mm [n = 61], 44 mm [n = 11]). High-risk criteria included: prior lumbosacral fusion (n = 170) or other inclusions (age ≥ 75, preoperative combined flexion-adduction-internal rotation ≥ 115°, substance abuse, inflammatory arthritis, neuromuscular disorder, removal of hardware, cognitive impairment, acute displaced femoral neck fracture, and kyphosis/scoliosis; n = 385). There were 28 patients (5.0%) lost to follow-up before 90 days, leaving 527 patients followed for a median of 23 months (range, 3.0 to 87.2). RESULTS:There were two dislocations in the DM group and six in the SB group (0.7 versus 2.1%, P = 0.29). There was no difference in 2-year dislocation-free survivorship between cohorts (DM: 99.0 versus SB: 97.6%; P = 0.63). There were 16 hips revised (DM: 2.2 versus SB: 3.5%; P = 0.45), with no difference in 2-year all-cause revision-free survivorship (DM: 97.5 versus SB: 96.4%; P = 0.53). Infection was the most common revision indication (two DM [0.7%] versus five SB [1.8%]). There were no differences in patient reported outcome measures at any time point (P > 0.05). CONCLUSION/CONCLUSIONS:In this multicenter RCT, DM bearings were associated with a threefold reduction in dislocation risk, but given the lower than anticipated overall dislocation rate, this difference did not reach statistical significance. Further follow-up is required to capture late dislocations or instability.

This study compared distance traveled by total joint arthroplasty (TJA) patients to surgeons' clinics who are language concordant (LC) versus language discordant (LD) with their surgeons. A retrospective review of all non-English speaking patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA), stratified according to language concordance, was conducted at a single institution between 2011 and 2021. The distance from home to clinic zip code where patients received TJA care was recorded. Of the 837 patients receiving THA, 401 (47.9%) were in the LD group and 436 (52.1%) were in the LC group. In total, 1,675 patients received TKA, with 874 (52.2%) in the LD group and 801 (47.8%) in the LC group. Both TKA and THA LD patients traveled significantly farther from home to clinic than the LC groups (p < 0.001). Non-English-speaking patients undergoing TJA who are language concordant with their surgeon may live closer to their surgeons' clinic. Level of Evidence: Level III. (Journal of Surgical Orthopaedic Advances 35(2):077-080, 2026).

BACKGROUND/UNASSIGNED:Osteoporosis (OP) is a common comorbidity in patients undergoing total hip arthroplasty (THA) and is a known risk factor for poor postoperative outcomes such as periprosthetic fracture (PPF). The impact of preoperative OP medications in patients with OP undergoing THA remains unclear. This study aimed to compare THA outcomes by OP diagnosis and preoperative bone strengthening medication usage. METHODS/UNASSIGNED:This was a retrospective review of primary elective THAs from June 2011-January 2024. Patients were stratified by OP diagnosis and OP medication usage, then propensity matched in a 1:2:3 ratio by age, sex, body mass index, and comorbidities. The resulting cohorts: (1) OP and medication usage for at least 1 year preoperatively and within 7 years of the procedure (n = 296), (2) OP and no medication usage (n = 592), and (3) no diagnosis of OP and no medication usage (n = 888) were then compared for postoperative outcomes. RESULTS/UNASSIGNED:= .009). Of the 12 revisions due to periprosthetic femoral fracture in cohorts 1 and 2 combined, 11 (91.7%) occurred around an uncemented implant. CONCLUSIONS/UNASSIGNED:Osteoporotic patients on OP medications did not have improved outcomes after THA compared with nonmedicated osteoporotic patients or those without a diagnosis of OP. PPF in osteoporotic patients overwhelmingly occurred around uncemented femoral implants. Surgeons should use caution when operating on osteoporotic patients, regardless of utilization of preoperative medications, and strongly consider using cemented femoral implants to decrease the risk of PPF.