Predictors of Patient Satisfaction Following Primary Total Knee Arthroplasty: Results from a Traditional Statistical Model and a Machine Learning Algorithm.

BACKGROUND: It is well-documented in the orthopedic literature that 1 in 5 patients are dissatisfied following total knee arthroplasty (TKA). However, multiple statistical models have failed to explain the causes of dissatisfaction. Furthermore, payers are interested in using patient-reported satisfaction scores to adjust surgeon reimbursement rates without a full understanding of the influencing parameters. The purpose of this study was to more comprehensively identify predictors of satisfaction and compare results using both a statistical model and a machine learning (ML) algorithm. METHODS: A retrospective review of consecutive TKAs performed by 2 surgeons was conducted. Identical perioperative protocols were utilized by both surgeons. Patients were grouped as satisfied or unsatisfied based on self-reported satisfaction scores. Fifteen variables were correlated with satisfaction using binary logistic regression and stochastic gradient boosted ML models. RESULTS: In total, 1325 consecutive TKAs were performed. After exclusions, 897 TKAs were available with minimum 1-year follow-up. Overall, 85.3% of patients were satisfied. Older age generation and performing surgeon were predictors of satisfaction in both models. The ML model also retained cruciate-retaining/condylar-stabilizing implant; lack of inflammatory conditions, preoperative narcotic use, depression, and lumbar spine pain; female gender; and a preserved posterior cruciate ligament as predictors of satisfaction which allowed for a significantly higher area under the receiver operator characteristic curve compared to the binary logistic regression model (0.81 vs 0.60). CONCLUSION: Findings indicate that patient satisfaction may be multifactorial with some factors beyond the scope of a surgeon's control. Further study is warranted to investigate predictors of patient satisfaction particularly with awareness of differences in results between traditional statistical models and ML algorithms. LEVEL OF EVIDENCE: Therapeutic Level III.

Prevalence of Pseudotumor in Patients After Metal-On-Metal Hip Arthroplasty Evaluated with Metal Ion Analysis and MARS-MRI.

The purpose of this study is to quantify the prevalence of pseudotumors in patients with well-functioning and painful metal-on-metal total hip arthroplasty, to characterize the pseudotumor with the use of MARS-MRI, and to assess the relationship between pseudotumors and metal ions. We retrospectively reviewed 102 single surgeon patients. The results showed that 68.6% developed pseudotumor with 60.9% of the asymptomatic group developing pseudotumor. The symptomatic group had a higher proportion of patients with elevated serum cobalt levels (P=0.035). There was no difference found with elevated metal ions and prevalence of pseudotumor, but elevated cobalt levels were associated with larger pseudotumor size (P=0.001). The available evidence indicated that most patients that develop pseudotumors are asymptomatic, and that elevated serum cobalt levels may be associated with symptoms and pseudotumor size.

Obtaining Volar Tilt in Distal Radius Fixation: Use of a Screw as a Proximal Post.

Volar plating of distal radius fractures was introduced as a means to circumvent some of the issues with dorsal-based plating but has been shown not to be a complete panacea, as other advantages and challenges have subsequently been discovered. Careful attention and proper technique must be utilized to restore and maintain volar tilt. This study reports a technique of using a locking screw as a proximal peg to reliably obtain the volar tilt in a simple fashion.

Difficulty of Total Hip Arthroplasty Following Open Reduction and Internal Fixation of Acetabular Fractures.

BACKGROUND: The incidence of posttraumatic arthrosis after acetabular fractures is significant, and patients frequently require secondary total hip arthroplasty. Conversion arthroplasty is more technically difficult, and there is higher risk than with routine primary total hip arthroplasty. The goal of this study was to identify the challenges and risks of secondary total hip arthroplasty compared to primary total hip arthroplasty. METHODS: We retrospectively identified 30 patients who underwent secondary total hip arthroplasty after open reduction and internal fixation of an acetabulum fracture and compared them with 20 patients who had undergone primary total hip arthroplasty for degenerative joint disease. RESULTS: Demographic data were similar between groups. Hardware removal was deemed necessary in 21 patients (70%). Allograft was needed for bone defects in 33% of secondary total hip arthroplasty cases, while no primary cases required grafting. Operative time (217.4 vs. 113.7 min, P < 0.01) and estimated blood loss (875.8 vs. 365 mL, P < 0.01) were significantly greater in the secondary arthroplasty group. Early postoperative complications were also higher in the secondary arthroplasty group. CONCLUSIONS: Total hip arthroplasty after acetabular fracture open reduction and internal fixation is a more complex procedure due to exposure difficulty, possible implant removal, management of bony deficits, and the potential use of cages and revision components. Experienced surgeons managing these complicated cases must take great care not only in ensuring appropriate technique but also in appropriate patient education regarding increased risk of major and minor complications. LEVEL OF EVIDENCE: Level III.

Safety of bilateral total knee arthroplasty in morbidly obese patients.

There has been an increase in the prevalence of morbid obesity and the demand for total knee arthroplasty (TKA). Physicians must help patients with bilateral knee arthritis to make informed decisions regarding whether to undergo staged, sequential, or simultaneous TKA. The purpose of this study was to evaluate the perioperative complications of 2-team simultaneous bilateral TKA in the morbidly obese. The authors performed a retrospective review of the records at a single tertiary hospital from 1997 to 2007 and identified 35 morbidly obese (body mass index [BMI] greater than 40 kg/m(2)) patients who had undergone unilateral TKA, as well as 42 morbidly obese and 79 nonobese (BMI less than 30 kg/m(2)) patients who underwent simultaneous bilateral TKA. Clinical, operative, and postoperative variables and complication rates were recorded. Clinical variables were similar between the morbidly obese TKA patients. The bilateral group had significantly increased operative times (132.4 vs 115.5 minutes; P<.01), intravenous fluids (2556.1 vs 2114.7 mL; P=.03), percentage transfused (64.2% vs 11.4%; P<.01), days in the hospital (3.6 vs 3.2 days; P=.03), and discharge rates to rehabilitation facility (72.7% vs 48.6%; P=.01). Major and minor complications were few and comparable, with the need for manipulation under anesthesia in unilateral TKA (11.4%; P=.04) as the only significant difference between groups, including when comparing bilateral nonobese TKAs with bilateral morbidly obese TKAs. The authors feel that morbidly obese patients may undergo 2-team simultaneous bilateral TKA after careful discussion regarding some of the differences in short-term outcomes.