Outpatient Total Knee Arthroplasty Shows Decreasing Complication Burden From 2010 to 2020.

BACKGROUND: The number of total knee arthroplasties (TKAs) performed on an outpatient basis continues to increase. The purpose of this study was to compare complication rates over the last decade to evaluate trends in the safety of outpatient TKA. METHODS: Patients who underwent TKA from 2010 to 2020 from a large administrative claims database were retrospectively identified and stratified based on the year of surgery. Propensity-score matching was performed to match patients who were discharged within 24 hours of surgery to inpatients based on age, sex, comorbidity index, and year of surgery. Linear regression analyses were used to compare trends from 2010 to 2020. The 90-day adverse events in the early cohort (2010-2012) were compared to those in the late cohort (2018-2020) using multivariable regression analyses. Of the 547,137 patients in the sample, 28,951 outpatients (5.3%) were propensity matched to inpatients. RESULTS: The incidence of outpatient TKA increased from 2010 to 2018 (1.9 versus 13.8%, P < .001). Despite a similar complication rate early (24.1 versus 22.6%, P = .164), outpatient TKA had fewer complications at the end of the study period (13.7 versus 16.7%, P < .001). Multivariate analyses demonstrated that the risk of any complication after outpatient TKA was lower than inpatient from 2018 to 2020 (odds ratio, 0.78; 95% confidence interval, 0.71-0.84). CONCLUSIONS: Complications in both cohorts declined dramatically suggesting improvements in quality of care over time, with the greatest decline in patients undergoing outpatient surgery. These results suggest that outpatient TKA today is not higher risk for the patient than inpatient TKA. LEVEL OF EVIDENCE: Level III.

Management of Periprosthetic Bone Cysts After Total Ankle Arthroplasty.

Modern improvements in total ankle arthroplasty (TAA) have increased the performance of this procedure for treatment of end-stage ankle arthritis. A common finding after TAA is the formation of periprosthetic bone cysts, which can be clinically silent or result in TAA failure. The exact cause of periprosthetic bones cysts has not been established, but major theories are related to osteolysis secondary to implant wear, micromotion, and stress shielding. Treatment can be nonoperative with clinical observation for small, asymptomatic cysts. Large, progressive, and symptomatic cysts often merit surgical treatment with debridement and grafting, revision TAA, or salvage arthrodesis.

Hypoalbuminemia Predicts Adverse Events following Unicompartmental Knee Arthroplasty.

Hypoalbuminemia is a potentially modifiable risk factor associated with adverse events following total knee arthroplasty. The present study aimed to evaluate whether hypoalbuminemia similarly predisposes to adverse events following unicompartmental knee arthroplasty (UKA). Patients who underwent UKA during 2006-2018 were identified through the American College of Surgeons National Surgical Quality Improvement Program. Only patients with preoperative serum albumin concentration were included. Outcomes were compared between patients with and without hypoalbuminemia (serum albumin concentration < 3.5 g/dL). All associations were adjusted for demographic, comorbidity, and laboratory differences between populations. A total of 11,342 patients were identified, of whom 6,049 (53.3%) had preoperative serum albumin laboratory values available for analysis. After adjustment for potential confounders, patients with hypoalbuminemia had a greater than 2-fold increased probability for occurrence of any complication (7.02% vs. 2.23%, p = 0.009) and a 4-fold increased probability of receiving a blood transfusion (1.81% vs. 0.25%, p = 0.045). Among procedures performed as inpatients, mean postoperative length of stay (LOS) was longer in patients with hypoalbuminemia (2.2 vs. 1.8 days; p = 0.031). Hypoalbuminemia is independently associated with complications and increased LOS following UKA and a marker for patients at higher risk of postoperative complications. Patients should be screened for hypoalbuminemia and nutritional deficiencies addressed prior to UKA.

Initial Impact of the COVID-19 Pandemic on a US Orthopaedic Foot and Ankle Clinic.

Background: In the United States, the COVID-19 pandemic led to a nationwide quarantine that forced individuals to adjust their daily activities, potentially impacting the burden of foot and ankle disease. The purpose of this study was to compare diagnoses made in an orthopaedic foot and ankle clinic during the shelter-in-place period of the COVID-19 pandemic to diagnoses made during the same months of the previous year. Methods: A retrospective review of new patients presenting to the clinics of 4 fellowship-trained orthopaedic foot and ankle surgeons in a major United States city was performed. Patients in the COVID-19 group presented between March 22 and July 1, 2020, during the peak of the quarantine for this city. Patients in the control group presented during the same period of 2019. Final diagnosis, chronicity of symptoms (acute: ≤1 month), and mechanism of disease were compared between groups. Results: A total of 1409 new patient visits were reviewed with 449 visits in the COVID-19 group and 960 visits in the control group. The COVID-19 group had a significantly higher proportion of ankle fractures (8.7% vs 5.4%, P = .020) and stress fractures (4.2% vs 2.2%, P = .031), but a smaller proportion of Achilles tendon ruptures (0.7% vs 2.5%, P = .019). The COVID-19 group had a higher proportion of acute injuries (35.4% vs 23.5%, P < .001). Conclusion: There was a shift in prevalence of pathology seen in the foot and ankle clinic during the COVID-19 pandemic, which may reflect the adoption of different activities during the quarantine period and reluctance to present for evaluation of non-urgent injuries. Level of Evidence: Level III, retrospective cohort study.

Fewer Adverse Events Following Outpatient Compared with Inpatient Unicompartmental Knee Arthroplasty.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is a common procedure for unicompartmental knee arthritis, often resulting in pain relief and improved function. The demand for total knee arthroplasty in the U.S. is projected to grow 85% between 2014 and 2030, and the volume of UKA procedures is growing 3 to 6 times faster than that of total knee arthroplasty. The purpose of the present study was to examine the safety of outpatient and inpatient UKA and to investigate changes over time as outpatient procedures were performed more frequently. METHODS: Patients who underwent UKA from 2005 to 2018 as part of the National Surgical Quality Improvement Program were identified. Patients were divided into an early cohort (5,555 patients from 2005 to 2015) and late cohort (5,627 patients from 2016 to 2018). Outpatient status was defined as discharge on the day of surgery. Adverse events within 30 days postoperatively were compared, with adjustment for baseline characteristics with use of standard multivariate regression and propensity-score-matching techniques. RESULTS: Among the 5,555 cases in the early cohort, the rate of surgical-site infection was lower for inpatient (0.84%) compared with outpatient UKA (1.69%; adjusted relative risk [RR] for inpatient, 0.5; 95% confidence interval [CI], 0.2 to 1.0; p = 0.045); no other significant differences were identified. Among the 5,627 cases in the late cohort, inpatient UKA had higher rates of any complication (2.53% compared with 0.95% for outpatient UKA; adjusted RR for inpatient, 2.5; 95% CI, 1.4 to 4.3; p = 0.001) and readmission (1.81% compared with 0.88% for outpatient UKA; adjusted RR for inpatient, 2.0; 95% CI, 1.1 to 3.5; p = 0.023). In the propensity-score-matched comparison for the late cohort, inpatient UKA had a higher rate of any complication (RR for inpatient, 2.0; 95% CI, 1.0 to 4.0; p = 0.049) and return to the operating room (RR for inpatient, 4.3; 95% CI, 1.4 to 12.6; p = 0.009). Although the rate of readmission was almost twice as high among inpatients (1.67% compared with 0.84% for outpatients; RR for inpatient, 2.0; 95% CI, 1.0 to 4.1; p = 0.059), this difference did not reach significance with the sample size studied. There was a significant reduction in the overall rate of complications over time (3.44% in the early cohort compared with 2.11% in the late cohort; adjusted RR for late cohort, 0.7; 95% CI, 0.5 to 0.8; p = 0.001), with a more than fourfold reduction among outpatients (3.95% in the early cohort compared with 0.95% in the late cohort; adjusted RR for late cohort, 0.3; 95% CI, 0.1 to 0.5; p < 0.001). CONCLUSIONS: Outpatient UKA was associated with a lower risk of complications compared with inpatient UKA when contemporary data are examined. We identified a dramatic reduction in complications across the early and late cohorts, suggesting an improvement in quality over time, with the largest improvements seen among outpatients. This shift may represent changes in patient selection or improvements in perioperative protocols. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Pathogenesis, Evaluation, and Management of Osteolysis Following Total Ankle Arthroplasty.

Periprosthetic osteolysis is a common occurrence after total ankle arthroplasty (TAA) and poses many challenges for the foot and ankle surgeon. Osteolysis may be asymptomatic and remain benign, or it may lead to component instability and require revision or arthrodesis. In this article, we present a current and comprehensive review of osteolysis in TAA with illustrative cases. We examine the basic science principles behind the etiology of osteolysis, discuss the workup of a patient with suspected osteolysis, and present a review of the evidence of various management strategies, including grafting of cysts, revision TAA, and arthrodesis.Level of Evidence: Level V, expert opinion.

Lateral Ligament Instability: Review of Pathology and Diagnosis.

PURPOSE OF REVIEW: Ankle sprains are a common injury that can lead to chronic lateral ankle instability resulting in pain, poor function, and decreased quality of life. The purpose of this review is to present information regarding injury mechanisms to the lateral ligaments of the ankle and the necessary steps to appropriately diagnose lateral ligament instability. RECENT FINDINGS: The literature demonstrates that history and physical examination is often a reliable method for diagnosis of lateral ankle instability. In addition, imaging modalities are often used as adjuncts for diagnosis, especially when physical exam findings are equivocal. In summary, chronic lateral ligament instability of the ankle occurs secondary to failure of the lateral ligamentous complex. A focused physical examination to evaluate the anterior talofibular ligament, calcaneofibular ligament, and posterior talofibular ligament is necessary for diagnosis. Imaging modalities including plain radiographs, stress radiographs, and MRI are helpful for definitive diagnosis and to rule out other pathology.

Second Metatarsophalangeal Joint Interpositional Arthroplasty Using Decellularized Human Dermal Allograft: Operative Technique.

Arthrodesis of an osteoarthritic second metatarsophalangeal (MTP) joint is suboptimal because of altered gait mechanics; hence, joint-preserving procedures are of value. Autograft interpositional arthroplasty is one available option with excellent results, but there are potential concerns regarding donor site morbidity and insufficiency of the autograft material. We present here an alternative technique, an interpositional arthroplasty using allograft. Our technique includes a dorsal incision and joint exposure, removal of cartilage from the metatarsal head, and interposition of human decellularized dermal allograft sutured to the metatarsal head. Allograft interpositional arthroplasty is a feasible technique and can be further investigated as an alternative procedure for patients with second MTP osteoarthritis. LEVEL OF EVIDENCE: Level V, expert opinion.

Molecular Mechanism for Isoform-Selective Inhibition of Acyl Protein Thioesterases 1 and 2 (APT1 and APT2).

Post-translational S-palmitoylation directs the trafficking and membrane localization of hundreds of cellular proteins, often involving a coordinated palmitoylation cycle that requires both protein acyl transferases (PATs) and acyl protein thioesterases (APTs) to actively redistribute S-palmitoylated proteins toward different cellular membrane compartments. This process is necessary for the trafficking and oncogenic signaling of S-palmitoylated Ras isoforms, and potentially many peripheral membrane proteins. The depalmitoylating enzymes APT1 and APT2 are separately conserved in all vertebrates, suggesting unique functional roles for each enzyme. The recent discovery of the APT isoform-selective inhibitors ML348 and ML349 has opened new possibilities to probe the function of each enzyme, yet it remains unclear how each inhibitor achieves orthogonal inhibition. Herein, we report the high-resolution structure of human APT2 in complex with ML349 (1.64 Å), as well as the complementary structure of human APT1 bound to ML348 (1.55 Å). Although the overall peptide backbone structures are nearly identical, each inhibitor adopts a distinct conformation within each active site. In APT1, the trifluoromethyl group of ML348 is positioned above the catalytic triad, but in APT2, the sulfonyl group of ML349 forms hydrogen bonds with active site resident waters to indirectly engage the catalytic triad and oxyanion hole. Reciprocal mutagenesis and activity profiling revealed several differing residues surrounding the active site that serve as critical gatekeepers for isoform accessibility and dynamics. Structural and biochemical analysis suggests the inhibitors occupy a putative acyl-binding region, establishing the mechanism for isoform-specific inhibition, hydrolysis of acyl substrates, and structural orthogonality important for future probe development.