Prevalence of Depressive Symptoms in Aseptic Revision Total Knee Arthroplasty Based on the Mode of Failure.

Background: Complications following total knee arthroplasty (TKA) that necessitate revision cause considerable psychological distress and symptoms of depression, which are linked to poorer postoperative outcomes, increased complications, and increased healthcare utilization. We aimed to identify the prevalence of mental health disorders and symptoms preoperatively and postoperatively in patients undergoing aseptic revision TKA and to stratify these patients based on their mechanism of failure. Methods: All patients undergoing aseptic revision TKA from 2008 to 2019 with a minimum 1-year follow-up were retrospectively reviewed at a single institution. Patients (n = 394) were grouped based on 7 failure modes previously described. Patients were considered to have depressive symptoms if their Veterans RAND-12 mental component score was below 42. Preoperative and postoperative Veterans RAND-12 mental component scores at the latest follow-up were evaluated. Results: Overall comparative prevalence of preoperative to postoperative depressive symptoms was 23.4%-18.8%. By mode of failure are as follows: arthrofibrosis (25.8%-16.7%), aseptic loosening (25.3%-18.9%), extensor mechanism disruption (25%-50%), failed unicompartmental knee arthroplasty (8.6%-14.3%), instability (25.7%-17.1%), osteolysis or polyethylene wear (23.1%-23.1%), and patellar failure (11.8%-23.5%). There was no difference in depressive symptoms among failure modes preoperatively (P = .376) or at the latest postoperative follow-up (P = .175). Conclusions: The prevalence of depressive symptoms in revision TKA patients appears to be independent of failure mode. Surgeon awareness and screening for depressive symptoms in this patient population preoperatively with referral for potential treatment may improve early postoperative outcomes.

Joint aspiration for diagnosis of chronic periprosthetic joint infection: when, how, and what tests?

Diagnosing chronic periprosthetic joint infection (PJI) requires clinical suspicion in combination with both serological and synovial fluid tests, the results of which are generally applied to validated scoring systems or consensus definitions for PJI. As no single "gold standard" test exists, the diagnosis becomes challenging, especially in the setting of negative cultures or equivocal test results. This review aims to address the workup of chronic PJI and considerations for clinical evaluation to guide treatment. Following aspiration of the joint in question, a multitude of tests has been developed in an attempt to assist with diagnosis, including cell synovial white blood cell count, gram stain, cultures, leukocyte esterase, alpha-defensin, synovial C-reactive protein, multiplex polymerase chain reaction, next-generation sequencing, and interleukins. Each test has advantages and disadvantages and should be used in conjunction with the overall clinical picture to guide further clinical evaluation and treatment in this complex patient population.

Functional Flexion Instability After Rotating-Platform Total Knee Arthroplasty.

BACKGROUND: We sought to define "at risk" loading conditions associated with rotating-platform total knee arthroplasty (TKA-RP) implants that predispose to insert subluxation and spinout and to quantify tolerances for flexion-extension gap asymmetry and laxity in order to prevent these adverse events. METHODS: Biomechanical testing was performed on 6 fresh-frozen cadaveric limbs with a TKA-RP implant with use of a gap-balancing technique, followed by sequential femoral component revision with variable-thickness polyethylene inserts to systematically represent 5 flexion-extension mismatch and asymmetry conditions. Each configuration was subjected to mechanical loading at 0°, 30°, and 60°. Rotational displacement of the insert on the tibial baseplate, lateral compartment separation, and insert concavity depth were measured with use of a digital caliper. Yield torque, a surrogate for ease of insert rotation and escape of the femoral component, was calculated with use of custom MATLAB code. RESULTS: Design-intended insert rotation decreased with increasing knee flexion angles in each loading configuration. Likewise, yield torque increased with increasing joint flexion and decreased with increasing joint laxity in all testing configurations. Insert instability and femoral condyle displacement were reproduced in positions of increasing knee flexion and asymmetrical flexion gap laxity. The depth of lateral polyethylene insert concavity determined femoral condylar capture and defined a narrow tolerance of <2 mm in the smallest implant sizes for flexion gap asymmetry leading to rotational insert instability. CONCLUSIONS: Decreased femoral-tibial articular surface conformity with increasing knee flexion and asymmetrical flexion gap laxity enable paradoxical motion of the femoral component on the upper insert surface rather than the undersurface, as designed. CLINICAL RELEVANCE: Mobile-bearing TKA-RP is a technically demanding procedure requiring a snug symmetrical flexion gap. As little as 2 mm of asymmetrical lateral flexion laxity can result in decreased conformity, condyle liftoff, and insert subluxation. Flexion beyond 30° decreases bearing surface contact area and predisposes to reduced insert rotation and mechanical malfunction.

Surgeon Reimbursement Unchanged as Hospital Charges and Reimbursements Increase for Total Joint Arthroplasty.

BACKGROUND: Despite increasing demands on physicians and hospitals to increase value and reduce unnecessary costs, reimbursement for healthcare services has been under downward pressure for several years. This study aimed to analyze the trend in hospital charges and payments relative to corresponding surgeon charges and payments in a Medicare population for total hip (THA) and knee arthroplasty (TKA). METHODS: The 5% Medicare sample database was used to capture hospital and surgeon charges and payments related to 56,228 patients who underwent primary THA and 117,698 patients who underwent primary TKA between 2005 and 2014. Two values were calculated: (1) the charge multiplier (CM), the ratio of hospital to surgeon charges and (2) the payment multiplier (PM), the ratio of hospital to surgeon payments. Year-to-year variation and regional trends in patient demographics, Charlson Comorbidity Index, length of stay (LOS), CM, and PM were evaluated. RESULTS: Hospital charges were significantly higher than surgeon charges and increased substantially for both THA (CM increased from 8.7 to 11.5, P < .0001) and TKA (CM increased from 7.9 to 11.4, P < .0001). PM followed a similar trend, increasing for both THA and TKA (P < .0001). LOS decreased significantly for both THA and TKA (P < .0001), while Charlson Comorbidity Index remained stable. Both CM (r2 = 0.84 THA, 0.90 TKA) and PM (r2 = 0.75 THA, 0.84 TKA) were strongly negatively associated with LOS. CONCLUSION: Hospital charges and payments relative to surgeon charges and payments have increased substantially for THA and TKA despite stable patient complexity and decreasing LOS.

Patients With Multiple Sclerosis are at Increased Risk for Postoperative Complications Following Total Hip and Knee Arthroplasty.

BACKGROUND: Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease affecting the central nervous system. Patients with MS are living longer due to improved medical therapy and thus the demand for arthroplasty in this population will increase. The objective of this study is to evaluate MS as a potential risk factor for postoperative complications following total hip arthroplasty (THA) and total knee arthroplasty (TKA). METHODS: Patients with a diagnosis of MS who underwent THA or TKA from 2005 to 2014 were identified in a national insurance database. Rates of death, hospital readmission, emergency room visits, infection, revision, and dislocation (for THA) or stiffness (for TKA) were calculated, in addition to cost and length of stay. MS patients were then compared to a matched control population. RESULTS: In total, 3360 patients who underwent THA and 6436 patients who underwent TKA with a history of MS were identified and compared with 10:1 matched control cohorts without MS. The MS group for both TKA and THA had significantly higher incidences of hospital readmission (THA odds ratio [OR] 2.05, P < .001; TKA OR 1.99, P < .001), emergency room visits (THA OR 1.41, P < .001; TKA OR 1.66, P < .001), and infection (THA OR 1.35, P = .001; TKA OR 1.32, P < .001). MS patients who underwent THA had significantly higher rates of revision (OR 1.35, P = .001) and dislocation (OR 1.52, P < .001). Diagnosis of MS was also associated with significantly higher costs and hospital length of stay for patients undergoing both TKA and THA. CONCLUSION: A diagnosis of MS is associated with increased risk of postoperative complications and higher costs following both THA and TKA.