Survivorship and Patient Outcomes of Conforming Bearings in Modern Primary Total Knee Arthroplasty: Mean 3.5 Year Follow-Up.

BACKGROUND: The use of conforming and congruent bearings in total knee arthroplasty (TKA) have rapidly increased due to the benefits of increased stability and the potential for replicating normal knee kinematics. However, limited data exist for these newly available bearings. This study evaluated revision-free survivorship and patient-reported outcome measures (PROMs) of a large granular database of primary TKAs using a single conforming bearing design. METHODS: A total of 1,306 consecutive primary TKAs performed using a single conforming bearing design (85% cemented and 15% cementless) were retrospectively reviewed. Kaplan-Meier survivorship estimates were calculated based on the latest clinical follow-up. The PROMs and minimal clinically important differences were evaluated. A total of 93% of cases achieved minimum 1-year clinical follow-up (mean 3.5 years; range, 1 to 7), with a subset of 261 cases that achieved minimum 5-year follow-up (mean 5.8 years; range, 5 to 7). RESULTS: All-cause and aseptic Kaplan-Meier survivorship estimates were 97.6 (95% CI [confidence interval], 97 to 99) and 98.1% (95% CI, 97 to 99) at 7.0 years. Revision-free survivorship did not differ by cemented or cementless fixation (98 versus 97%, P = .163). All PROM scores significantly improved from preoperative baseline (P < .001), and ≥ 86% of patients achieved minimal clinically important differences for Knee Society pain and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement total scores. A total of 89% of cases reported their knees to 'sometimes or always' feel normal. For cases with minimum 5-year PROMs, 93% were 'very satisfied' or 'satisfied.' CONCLUSIONS: Conforming-bearing TKA demonstrated excellent survivorship up to 7.0 years. In addition, PROMs were comparable to other designs reported in the literature. While mid-term (mean 3.5-year) results are promising, long-term data are warranted on survivorship due to potential polyethylene wear in conforming bearings with more surface area in contact with articulating surfaces. LEVEL OF EVIDENCE: IV.

Efficacy and Safety of Catheter Interventions for Postoperative Urinary Retention After Primary Hip and Knee Total Joint Arthroplasty.

INTRODUCTION: Postoperative urinary retention (POUR) is a common barrier to rapid-discharge hip and knee total joint arthroplasty (TJA). We evaluated the efficacy and safety of catheterization intervention methods for POUR before and after discharge. METHODS: A total of 1,659 primary TJAs were retrospectively reviewed. POUR resolutions before and after discharge were evaluated relative to catheterization type and other covariates. Complications before and within 90 days of discharge were quantified. A total of 113 POUR cases comprised the analysis sample of 76 hips and 37 knees in 51 women and 62 men with an average age and body mass index of 68.6 (range 22 to 92) years and 31.7 (range 16 to 49) kg/m2. RESULTS: POUR resolved before discharge for 82.3% (93/113) of patients, with equivalent resolution rates for intermittent catheterization alone (84.2%, 32/38) compared with indwelling catheterization with or without intermittent catheterization (82.6%, 57/69, P < 0.999), equivalent time to resolution (P = 0.319), and no difference in complication rates (P = 0.999). Complication rates within 90 days of discharge were higher for patients treated with indwelling catheters before discharge (P = 0.049). Resolution before discharge was more likely with increasing body mass index (P = 0.026) and less likely for patients with a history of urinary retention (P = 0.033). 60 percent (12/20) of patients with unresolved POUR were discharged with self-intermittent catheterization and 40% (8/20) with indwelling catheters, with no differences in efficacy and safety based on the catheterization type (P = 0.109). DISCUSSION: Before discharge, we observed equivalent resolution rates and equivalent time to resolution for indwelling and intermittent catheterization alone without compromising patient safety. Intermittent catheterization is favored, however, because in situ catheter exposure is dramatically reduced and postdischarge complication rates are lower. Additional research is needed to develop evidence-based POUR guidelines for outpatient TJA.

Durability of Primary Total Hip Arthroplasty With Cementless Stems Without a Collar in Elderly Patients Age 75 Years and Over.

BACKGROUND: Cementless femoral fixation in total hip arthroplasty (THA) has increased in prevalence worldwide. However, cementless fixation in elderly patients is controversial due to the risks of periprosthetic fracture and aseptic loosening. This study evaluated outcomes in patients undergoing primary THA utilizing a cementless stem without a collar, comparing those less than 75 years to those older than 75 years. METHODS: Between 2011 and 2021, there were 2,605 cementless THAs performed by 4 surgeons utilizing a highly porous metal fixation surface without a collar and consistent clinical protocols. There were 469 patients who had an age ≥ 75 years. Revision rates, intraoperative fractures, and 90-day mortality were compared between cohorts. In the ≥ 75 year age group, there were more women, more American Society of Anesthesiologists physical status classification III or IV, a lower body mass index, and more kidney disease, osteoporosis, and thyroid disease (P ≤ .002). RESULTS: All-cause revision rates trended lower for the ≥75 year age group compared to < 75 year (1.9 versus 3.5%, P = .082) at 20-months of follow-up. Moreover, there was no difference in all-cause femoral component revisions comparing ≥ 75 to < 75 year age groups (1.5 versus 2.2%, P = .375), with only 3 of 10 femoral revisions due to aseptic loosening being in the ≥ 75 year age group. Intraoperative fracture (0.2 versus 0.5%, P = .701) and 90-day mortality (0.2 versus 0.1%, P = .460) did not differ between ≥ 75 and < 75 year age groups. CONCLUSIONS: Older patients had comparable revision rates compared to younger patients using cementless femoral fixation without a collar. Furthermore, there was no difference in 90-day mortality or intraoperative fracture rates. Study findings provide evidence for the safety and durability of cementless THA using collarless femoral stems in elderly patients ≥ 75 years of age. LEVEL OF EVIDENCE: III.

Instability in Patients With Lumbar Spine Disease Undergoing Posterior Approach and Lateral Approach Primary Total Hip Arthroplasty.

INTRODUCTION: Dislocation rates in patients who have fixed spinopelvic motion have been reported up to 20%. Few studies have directly compared dislocation rates in patients who have spine pathology undergoing total hip arthroplasty (THA) through different surgical approaches. This study compared postoperative dislocation rates in patients who had lumbar spine disease and underwent primary THA using a posterior or direct lateral approach. METHODS: Between 2011 and 2017, consecutive cohorts of primary THAs were retrospectively reviewed. One surgeon routinely used a posterior approach, while the other used a direct lateral approach. Chart and radiographic review were conducted to identify patients who had lumbar spine disease. Dislocations among cohorts with and without lumbar spine disease were compared by posterior and direct lateral approaches. RESULTS: The overall dislocation rate was 1.3% (15/1,198). The top four predictors of dislocation were presence of lumbar spine disease (odds ratio [OR] 5.0; P = 0.014), posterior surgical approach (OR, 6.5; P = 0.074), cases performed for fracture (OR, 4.4; P = 0.035), and women (OR, 4.6; P = 0.050). Dislocation rates among direct lateral approach patients who had lumbar spine pathology were significantly lower than posterior approach patients who had lumbar spine pathology (0.0% versus 3.6%; P = 0.011). DISCUSSION: Although dislocation rates were low in both groups, study results suggest that a direct lateral approach for primary THA may reduce postoperative dislocations for patients who have limited spinopelvic motion due to lumbar spine pathology. Furthermore, surgeons using the posterior approach might consider optimizing the femoral head to acetabular cup ratio in patients who have lumbar spine disease.

Incidence and Predictors of Subsidence Using Modular, Tapered, Fluted Titanium Femoral Stems in Aseptic Revision Total Hip Arthroplasty.

BACKGROUND: Tapered, fluted titanium (TFT) femoral stems have become the gold standard in revision total hip arthroplasty (rTHA). However, there is a paucity of data on TFT stem subsidence rates following aseptic rTHA. Subsidence can lead to instability, mechanical failure, leg-length discrepancy, and may require revision surgery. This study evaluated the incidences and predictors of TFT subsidence in aseptic rTHA. METHODS: A total of 102 TFT femoral stems of 4 designs were retrospectively reviewed. Stem subsidence was measured on digital radiographs taken immediately after surgery and at standard clinical follow-up. Patient characteristics, risk factors for subsidence, revision etiologies, and implant characteristics were recorded. Patient-reported outcome measures were also evaluated for a subset of cases. RESULTS: Overall, 12% of stems subsided >1 cm, and subsidence was minimal (<3 mm) in ≥64% of cases. From immediate postoperative to 1-month radiographic follow-up, 79% of stems subsided a mean of 2.9 mm (range, 0.1 to 12 mm). Beyond 1 month, subsidence was minimal for ≥77% of cases. In multivariate analyses, women and less femoral implant canal fill were associated with greater subsidence (P ≤ .034). The TFT stem design was not associated with early subsidence (P = .816). There were no modular junction fractures. There were 2 fractures and 2 subsidence-related revisions for aseptic loosening that occurred postoperatively. CONCLUSIONS: The amount of subsidence in TFT stems was low and was detectable in the early (less than 1 year) postoperative period. Maximizing TFT stem fill within the femoral canal appears to reduce the risk of subsidence without increasing femoral fracture rates and should be the goal with implantation of these devices. LEVEL OF EVIDENCE: IV-Case Series, No Control Group.

Nutritional Laboratory Studies Prior to Total Knee Arthroplasty: Practice Versus Publication.

BACKGROUND: Recent emphasis has been placed on nutritional status assessment prior to total knee arthroplasty (TKA), including multiple American Academy of Orthopaedic Surgeons publications recommending specific laboratory studies; however, the frequency with which surgeons obtain these laboratory studies remains unclear. We sought to assess the incidence of ordering nutritional laboratory studies in the 90 days prior to TKA, utilizing data from a large administrative claims database. METHODS: With use of the PearlDiver database, we identified 557,670 patients undergoing primary TKA from 2011 to 2020 with a metabolic panel or blood cell count claim within 90 days prior to TKA. We then determined the incidence of prealbumin, transferrin, vitamin D, and zinc laboratory tests claimed 90 days prior to TKA. Associations between claims and the year of surgery, patient demographics, and clinical characteristics were assessed by comparing proportions and chi-square testing. RESULTS: Nutritional laboratory studies were infrequently claimed within 90 days prior to TKA, with studies for prealbumin being performed in 2.2% of patients; transferrin, 1.9%; vitamin D, 10.2%; and zinc, 0.2%. From 2011 to 2020, there was a moderate but steady increase in the proportion of patients with claims for prealbumin (change from 0.8% in 2011 to 3.4% in 2020; p < 0.001), transferrin (0.8% to 2.7%; p < 0.001), and vitamin D (7.6% to 9.4%; p < 0.001) laboratory tests but there was less of a change for zinc (0.1% to 0.2%; p < 0.001). There were weak-to-absent associations of age, gender, obesity, diabetes, and anemia with laboratory claims. CONCLUSIONS: Despite multiple publications and recommendations, nutritional laboratory studies are infrequently ordered prior to TKA. Although there has been a slight increase in the use of nutritional laboratory studies over the past decade, patient factors such as gender and obesity were not associated with this increase. Understanding current practice patterns may help target future areas for improvement. LEVEL OF EVIDENCE: Diagnostic Level III . See Instructions for Authors for a complete description of levels of evidence.

Obesity is Associated With Greater Improvement in Patient-Reported Outcomes Following Primary Total Knee Arthroplasty.

BACKGROUND: Body mass index (BMI) cutoffs have been established for total knee arthroplasty (TKA) patients due to increased risk of medical complications in obese patients. However, evidence-based medical optimization may mitigate risk in these patients. This study examined the influence of BMI on patient-reported outcome measures (PROMs) following primary TKA with specialized perioperative optimization. METHODS: Between 2016 and 2020, 1,329 consecutive primary TKAs using standardized perioperative optimization were retrospectively reviewed. Patients were categorized into ordinal groups based on BMI in 5 kg/m2 increments (range, 17 to 61). Primary outcomes related to activity level, pain, function, and satisfaction were evaluated. BMI groups ≥35 had significantly lower age, more women, and higher prevalence of comorbidities (P ≤ .004). Mean follow-up was 1.7 years (range, 1 to 5 years). RESULTS: Each successive BMI group from 35 to ≥50 demonstrated continually greater improvement in pain with level walking and stair climbing (P ≤ .001), Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (P = .001), and greater satisfaction (P = .007). No patients who had a BMI ≥35 were revised for aseptic loosening, and rates of periprosthetic joint infection were not different between BMI groups (P = 1.000). CONCLUSION: Despite being more debilitated preoperatively, patients who had a BMI ≥35 experienced greater improvements in PROMs compared to patients who had lower BMI. Given the significant improvements in PROMs and quality of life in obese patients, with appropriate perioperative optimization, these patients should not be prohibited from having a TKA when appropriately indicated. LEVEL OF EVIDENCE: III.

Time Required for Planned and Unplanned Episodes of Care in Aseptic Hip and Knee Revision Arthroplasty.

BACKGROUND: Studies indicate aseptic revision total hip arthroplasty (rTHA) and revision total knee arthroplasty (rTKA) requires much more effort but is reimbursed less than primary procedures per minute work time. This study quantified planned and unplanned work performed by the surgeon and/or their team during the entire episode of care "reimbursement window" and compared it to allowed reimbursement times by Centers for Medicare and Medicaid Services (CMS). METHODS: Between October, 2010, and December, 2020, all unilateral aseptic rTHA and rTKA procedures performed by a single surgeon at a single institution were retrospectively reviewed. Time dedicated to planned work was calculated from surgery scheduling to 90 days postoperative. Impromptu patient inquiries and treatments after discharge but within the episode of care, involving the surgeon/surgeon team constituted unplanned work. Planned and unplanned work minutes were summed and divided by the number of patients reviewed to obtain average minutes of work per patient. Work time was compared to CMS allowable times for rTHA (617 minutes) and rTKA (520 minutes). RESULTS: There were 292 Aseptic rTKA and 63 aseptic rTHA procedures included. Based upon CMS allowable times per patient there were a mean of 4.4 hours (267 minutes) of uncompensated care time per rTKA patient and a mean of 2.4 hours (141 minutes) of uncompensated care time per rTHA patient. CONCLUSION: Aseptic revisions are substantially more complex than primaries, requiring work effort that is not commensurate with current reimbursements. Financially disincentivizing surgeons to care for patients requiring revision surgery could reduce patient access to care when high quality care is needed the most.

Patients With Previous COVID-19 Infection Can Safely Undergo Primary Total Joint Arthroplasty.

BACKGROUND: The COVID-19 virus is believed to increase the risk of diffusing intravascular coagulation. Total joint arthroplasty (TJA) is one of the most common elective surgeries and is also associated with a temporarily increased risk of venous thromboembolism (VTE). However, the influence of a history of COVID-19 infection on perioperative outcomes following TJA remains unknown. Therefore, this study sought to determine what effect a history of COVID-19 infection had on outcomes following primary TJA. METHODS: A retrospective case-control study using the national database was performed to identify all patients who had a history of COVID-19 and had undergone TJA, between 2019 and 2020. Patients who had a history of both were 1:1 matched to those who did not have a history of COVID-19, and 90-day outcomes were compared. A total of 661 TKA and 635 THA patients who had a history of COVID-19 were 1:1 matched to controls. There were no differences in demographics and comorbidities between the propensity-matched pairs in both TKAs and THAs studied. Previous COVID-19 diagnosis was noted in 28.3% of patients 5 days within TJA and in 78.6%, 90 days before TJA. RESULTS: Patients who had a previous diagnosis of COVID-19 had a higher risk of pneumonia during the postoperative period for both THA and TKA (6.9% versus 3.5%, P < .001 and 2.27% versus 1.21%, P = .04, respectively). Mean lengths of stay were also greater for those with a previous COVID-19 infection in both cohorts (TKA: 3.12 versus 2.57, P = .027, THA: 4.52 versus 3.62, P < .001). Other postoperative outcomes were similar between the 2 groups. CONCLUSION: COVID-19 infection history does not appear to increase the risk of VTE following primary TJA, but appears to increase the risk of pneumonia in addition to lengths of stay postoperatively. Individual risk factors should be discussed with patients, to set reasonable expectations regarding perioperative outcomes.

Same-Day Discharge Following Aseptic Revision and Conversion Total Joint Arthroplasty: A Single-Institution Experience.

Background: With hospital inpatient capacity increasingly limited and primary total joint arthroplasty (TJA) rapidly transitioning to outpatient settings, the feasibility of outpatient aseptic revision and conversion TJA (rTJA) has been considered. Before the widespread adoption of outpatient rTJA, guidelines must be established to prevent patient harm. To this end, this study describes our initial experience with same-day-discharge (SDD) aseptic rTJA. Methods: All aseptic rTJAs performed between May 8, 2015, and December 30, 2021, were retrospectively reviewed. Revision indications, patient selection criteria, and outcomes including SDD success rate, predischarge complications, all-cause emergency department visits, inpatient readmissions, and unplanned clinic encounters within 90 days of surgery were recorded. Results: Thirty-five SDD aseptic rTJAs were performed. Conversion total hip arthroplasty (55.0%) and instability (27.3%) were the most common indications for hip revision. Instability (50%) and conversion total knee arthroplasty (20.8%) were most common for knee revision. SDD was achieved in 97% (34/35) of cases. One hip patient failed SDD due to persistent hypoxia requiring an overnight hospital stay and also underwent closed reduction for dislocation in the emergency department within 90 days of discharge. Two additional patients had unplanned clinic encounters within 90 days of the index procedure. There were no hospital readmissions or reoperations within 90 days. Conclusions: Our initial experience suggests SDD aseptic rTJA can be safe and effective when modern perioperative outpatient protocols and surgical techniques are implemented. Future studies should further define patient selection criteria to optimize outcomes and minimize complications in this population.

The Fate and Relevance of the Patella in Two-Stage Revision Total Knee Arthroplasty for Periprosthetic Joint Infection.

BACKGROUND: It remains unclear whether reimplantation of a patellar component during a two-stage revision for periprosthetic total knee arthroplasty infection (PJI) affects patient reported outcome measures (PROMs) or implant survivorship. The purpose of this study was to evaluate whether patellar resurfacing during reimplantation confers a functional benefit or increases implant survivorship after two-stage treatment for PJI. METHODS: Two-stage revisions for knee PJI performed by three surgeons at a single tertiary care center were reviewed retrospectively. All original patellar components and cement were removed during resection and the patella was resurfaced whenever feasible during reimplantation. PROMs, implant survivorship, and radiographic measurements (patellar tilt and displacement) were compared between knees reimplanted with a patellar component versus those without a patellar component. RESULTS: A total of 103 patients met the inclusion criteria. Forty-three patients (41.7%) underwent reimplantation with, and 60 patients (58.3%) without a patellar component. At a mean follow-up of 33.5 months, there were no significant differences in patient demographics or PROMs between groups (P ≥ .156). No significant differences were found in the estimated Kaplan-Meier all-cause, aseptic, or septic survivorship between groups (P ≥ .342) at a maximum of 75 months follow-up. There was no significant difference in the change (pre-resection to post-reimplant) of patellar tilt (P = .504) or displacement (P = .097) between the groups. CONCLUSION: Patellar resurfacing during knee reimplantation does not appear to meaningfully impact postoperative PROMs or survivorship. Given the risk of potential extensor mechanism complications with patellar resurfacing, surgeons may choose to leave the patella without an implant during total knee reimplantation and expect similar clinical outcomes. LEVEL OF EVIDENCE: Level III.

Dually Insured Medicare/Medicaid Patients Undergoing Primary TJA Have More Comorbidities, Higher Complication Rates, and Lower Reimbursements Compared to Privately Insured Patients.

BACKGROUND: Dual eligibility status (DES: qualifying for both Medicare and a Medicaid supplement) was recently proposed by the Center for Medicare and Medicaid Services as a socioeconomic qualifier for risk adjustment in primary total joint arthroplasty. However, the profile and outcomes of DES patients have never been compared to privately insured patients. METHODS: A retrospective case-control study of the Mariner database within the PearlDiver server between 2010 and 2017 was performed. Patients aged 60 to 80 undergoing primary total hip arthroplasty (THA) and total knee arthroplasty (TKA) (separately) were stratified based upon payer type: DES versus private payer. A propensity score-matched analysis with nearest neighbor pairing (1:1 ratio) was performed to compare 90-day outcomes and reimbursements. RESULTS: A total of 315,664 private and 3961 DES THA patients and 670,899 private and 2255 DES TKA patients were identified. DES patients were older and had a greater prevalence of comorbidities (31/36, P < .001). The THA DES matched cohort had greater transfusion rates (6.8% versus 3.9%, P < .001), higher 90-day emergency department visits (22.8% versus 16.3%, P < .001) and readmissions (16.8% versus 9.5%, P < .001), and lower reimbursements ($19,615 versus $13,036, P < .001). The TKA DES matched cohort had more cardiac events (0.4% versus 0.09%, P = .03), emergency department visits (25.2% versus 19.9%, P < .001), readmissions (14.4% versus 11.2%, P = .001), and reoperations (0.85% versus 0.35%, P = .03) CONCLUSION: DES patients have different comorbidity profiles, and even after propensity score matching have a greater risk of complications and are reimbursed less compared to privately insured patients. In the setting of alternative payment models, these differences should be accounted for through risk adjustment.

The Effect of Joint Line Elevation on Patient-Reported Outcomes After Contemporary Revision Total Knee Arthroplasty.

BACKGROUND: Joint line elevation in revision total knee arthroplasty (rTKA) is considered a risk factor for inferior outcomes, engendering a dogmatic protocol of joint line restoration. However, this precedent is based on historical data using rudimentary revision systems and unvalidated outcome measures. This study's purpose was to evaluate the effect of joint line height elevation on validated patient-reported outcome measures (PROMs) using modern revision implants. METHODS: A total of 327 rTKAs performed at a single institution were reviewed. Surgical technique prioritized flexion-extension gap balancing and accepted joint line elevation if necessary to achieve a balanced flexion space. Radiographic measurements included changes in joint line height (from preoperative and calculated "intended" anatomic/native) and change in posterior condylar offset. Prospectively collected PROMs were evaluated using multivariate regression. RESULTS: The mean joint line elevation from preoperative and "intended" to postoperative joint line was 4.9 ± 5.7 mm and 7.2 ± 6.6 mm, respectively. The mean increase in posterior condylar offset was 1.0 ± 4.6 mm. Patients within ±5 mm of preoperative joint line height were 3.88× more likely to achieve the substantial clinical benefit for Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (P = .004). An increase from intended joint line height >5 mm was not associated with differences in any other PROMs (P ≥ .165). CONCLUSIONS: In contemporary rTKA, recreating the joint line within 5 mm of preoperative improves knee-specific health outcomes. These data support approximating native joint line height as a viable technique to optimize flexion gap balance and subsequent patient outcomes in rTKA. LEVEL OF EVIDENCE: Level III retrospective cohort study.

Time Required for Planned and Unplanned Episodes of Care in Septic Two-Stage Revision Hip and Knee Arthroplasty.

BACKGROUND: Septic revision total hip (rTHA) and knee (rTKA) arthroplasty requires more effort but is reimbursed less than primary procedures per minute of intraoperative time. This study quantified planned and unplanned work performed by the surgical team for septic 2-stage revision surgeries during the entire episode-of-care "reimbursement window" and compared that time to allowable reimbursement amounts. METHODS: Between October 2010 and December 2020 all unilateral septic 2-stage rTHA and rTKA procedures performed by a single surgeon at a single institution were retrospectively reviewed. Time dedicated to planned work was calculated over each episode of care, from surgery scheduling to 90 days postoperatively. Impromptu patient inquiries and treatments after discharge, but within the episode of care, involving the surgeon/surgeon team constituted unplanned work. Planned and unplanned work minutes were summed and divided by the number of patients reviewed to obtain average minutes of work per patient. RESULTS: Sixty-eight hips and 64 knees were included. For 2-stage rTHA and rTKA the average time per patient for planned care was 1728 and 1716 minutes and for unplanned care was 339 and 237 minutes. Compared to the Centers for Medicare and Medicaid Services' allowable reimbursement times, an additional 799 and 887 minutes of uncompensated time was required to care for 2-stage rTHA and rTKA patients. CONCLUSION: Two-stage revision procedures are substantially more complex than primary procedures. Financially disincentivizing surgeons to care for these patients reduces access to care when high-quality care is most needed. These findings support increasing the allowable times for 2-stage septic revision cases.

Tibial baseplate position and posterior cruciate ligament status impact patient-reported outcomes in conforming dual-pivot bearing total knee arthroplasty.

BACKGROUND: In an effort to optimize clinical outcomes and enhance stability, ultracongruent bearings have been increasingly used in primary total knee arthroplasty (TKA). The importance of the posterior cruciate ligament (PCL) and optimal sagittal tibial baseplate position in ultracongruent bearing TKA remains unknown. This study sought to determine whether these modifiable, surgical-technique-dependent variables meaningfully impact patient-reported outcome measures. METHODS: A total of 759 primary TKAs of the same dual-pivot design performed using a consistent surgical technique between January 2016 and April 2019 were retrospectively reviewed. PCL status was recorded, and anteroposterior (AP) tibial baseplate position and posterior tibial slope were measured by two independent blinded raters. Patient-reported outcomes related to pain, function, satisfaction, and activity level were analyzed in relationship to PCL status, posterior tibial slope, and AP tibial baseplate position, in addition to other pertinent covariates. RESULTS: Median age and body mass index of the cohort were 68.3 years and 33.4 kg/m2, respectively, with 73% being female. In multivariate analysis, partial or full release of the PCL was predictive of a knee "always" feeling normal (odds ratio 1.42, P = .041). Furthermore, tibial baseplate position closer to the middle of the tibia was associated with greater improvements in pain with level walking, pain while climbing stairs, and Knee Injury and Osteoarthritis Outcome Score for Joint Replacement total scores (P ≤ .079). CONCLUSION: In congruent dual-pivot bearing TKA, partially or fully releasing the PCL and AP tibial baseplate position closer to the middle of the tibia may provide greater improvement in pain and function scores at minimum 1-year follow-up.

Complications and Outcomes Associated With a Novel, Prefabricated, Articulating Spacer for Two-Stage Periprosthetic Joint Infection Treatment.

BACKGROUND: Various prefabricated articulating spacer options have been described for 2-stage treatment of chronic periprosthetic joint infection, but their results are poorly generalizable between designs due to differing antibiotic and material properties. This study reports outcomes for a novel, prefabricated, commercially available cement-on-cement articulating spacer. METHODS: A retrospective review of prospectively collected data for patients undergoing treatment with a prefabricated articulating cement spacer was performed. Outcomes were categorized as spacer complications, reimplantation rates, function, reinfection, and mortality. RESULTS: Seventy-six knees and 28 hips were analyzed. Spacer survival free of fracture, instability, or other implant-related complication until reimplantation was 100%. There were no bony or spacer fractures during the interstage or reimplantation. Reimplantation occurred in 84.6% of resected joints. Following spacer implantation, all but 1 patient was allowed to bear weight. The proportion of patients requiring an assistive device decreased from 67% prior to resection to 31% following reimplantation. Knee flexion improved from an average of 88.1° before resection to 111.9° following reimplantation. Eighty-seven percent of cases were infection free at mean follow-up of 16.6 ± 10.4 months. CONCLUSION: Study results demonstrate that this novel, prefabricated, articulating antibiotic spacer is safe, allows for good interstage function, and results in reasonable infection eradication rates at early term follow-up. LEVEL OF EVIDENCE: Therapeutic Level III.

Comparison of Surgical Site Complications With Negative Pressure Wound Therapy vs Silver Impregnated Dressing in High-Risk Total Knee Arthroplasty Patients: A Matched Cohort Study.

BACKGROUND: Closed incision negative pressure wound therapy (ciNPWT) may reduce surgical site complications following total joint arthroplasty. Although unlikely necessary for all patients, the criteria for utilizing ciNPWT in primary total knee arthroplasty (TKA) remain poorly defined. This study's purpose was to compare the incidence of incisional wound complications, non-incisional complications (ie, dressing reactions), reoperations, and periprosthetic joint infections (PJIs) among a group of high-risk primary TKA patients treated with ciNPWT vs an occlusive silver impregnated dressing. METHODS: One hundred thirty high-risk primary TKA patients treated with ciNPWT were 1:1 propensity matched and compared to a historical control group treated with an occlusive silver impregnated dressing. High-risk criteria included the following: active tobacco use, diabetes mellitus, body mass index >35 kg/m2, autoimmune disease, chronic kidney disease, Staphylococcus aureus nasal colonization, and non-aspirin anticoagulation. RESULTS: Age, gender, and risk factor profile were comparable between cohorts. The ciNPWT cohort had significantly fewer incisional wound complications (6.9% vs 16.2%; P = .031) and significantly more non-incisional complications (16.9% vs 1.5%; P < .001). No dressing reactions required clinical intervention. There were no differences in reoperations or periprosthetic joint infections (P = 1.000). In multivariate analysis, occlusive silver impregnated dressings (odds ratio 2.9, 95% confidence interval 1.3-6.8, P = .012) and non-aspirin anticoagulation (odds ratio 2.5, 95% confidence interval 1.1-5.6, P = .028) were associated with the development of incisional wound complications. CONCLUSION: Among high-risk patients undergoing primary TKA, ciNPWT decreased incisional wound complications when compared to occlusive silver impregnated dressings, particularly among those receiving non-aspirin anticoagulation. Although an increase in dressing reactions was observed, the clinical impact was minimal.