Cryoneurolysis before Total Knee Arthroplasty in Patients With Severe Osteoarthritis for Reduction of Postoperative Pain and Opioid Use in a Single-Center Randomized Controlled Trial.

BACKGROUND: We hypothesized that preoperative cryoneurolysis of the superficial genicular nerves in patients with osteoarthritis would decrease postoperative opioid use relative to standard of care (SOC) treatment in patients undergoing total knee arthroplasty (TKA). METHODS: Patients received either cryoneurolysis (intent-to-treat [ITT]: n = 62) or SOC (ITT: n = 62). The cryoneurolysis group received cryoneurolysis of the superficial genicular nerves 3-7 days before surgery plus a similar preoperative, intraoperative, and postoperative pain management protocol as the SOC group. The primary end point was cumulative opioid consumption in total daily morphine equivalents from discharge to the 6-week study follow-up assessment. Secondary end points included changes in pain and functional scores. Primary and secondary end points were assessed using ITT and per-protocol (PP) analyses. RESULTS: The primary end point was not met in the ITT analysis (4.8 [cryoneurolysis] vs 6.1 [SOC] mg; P = .0841) but was met in the PP analysis (4.2 vs 5.9 mg; P = .0186) after excluding patients with medication deviations or missing follow-up data. Compared with the SOC group, the cryoneurolysis group had improved functional scores and numerical improvements in pain scores across all follow-up assessments, with significant improvements observed in current pain from baseline to the 72-hour and 2-week follow-up assessments and pain in the past week from baseline to the 12-week follow-up assessment. CONCLUSION: Findings from the PP analysis suggest that preoperative cryoneurolysis in patients with knee osteoarthritis can reduce opioid consumption and improve functional outcomes after TKA.

Is Soft Tissue Laxity Associated with Tissue Metal Concentrations after Total Knee Arthroplasty?

Increased joint laxity is associated with excessive polyethylene wear, but the correlation between laxity and metal wear has not been established. Fifteen necropsy-retrieved primary total knee replacements were mounted into a custom knee-testing machine that measured anterior-posterior, varus-valgus, and internal-external rotational laxity at 0°, 30°, 60°, and 90° of flexion. Inductively coupled plasma-mass spectrometry analysis was performed to measure the cobalt (Co), chromium (Cr), and titanium (Ti) concentrations in periprosthetic tissue samples. Spearman's rank correlations were performed to determine whether a significant correlation (p < 0.05) existed between soft tissue laxity and tissue metal concentrations. At 0° flexion, decreased posterior displacement was negatively correlated with elevated Co and Cr concentrations. At 30° flexion, decreased external rotation and varus deflection was negatively correlated with elevated Ti concentrations. At 60° flexion, decreased anterior displacement was negatively correlated with elevated Cr concentrations and decreased varus deflection was negatively correlated with increased Ti concentrations. At 90° flexion, decreased anterior displacement was negatively correlated with elevated Co and Cr concentrations. To our knowledge, this is the first study to investigate the correlation between tissue metal concentration and laxity. Decreased laxity was associated with elevated metal concentrations in periprosthetic tissue.

Is Gelsolin a Biomarker for Aseptic Loosening After Total Knee Arthroplasty?

Gelsolin (GSN) has been implicated in inflammatory reactions in asthmatic patients and may be a marker for acute or chronic reactions in synovial tissue. Detection of increased levels of GSN in synovial fluid could differentiate between aseptic loosening (low GSN) and hypersensitivity reaction (high GSN). Synovial fluid from both knees of 7 cadaver specimens with unilateral TKA was analyzed using ELISA for GSN levels. Components were explanted after spiral CT scans to determine wear patterns and loosening. Results were compared to synovial fluid from 7 consecutive TKA revisions for aseptic failure. Average GSN levels for cadaver native and well-functioning TKA knees were 24,534±10,437 ng/mL and 38,430±30,907 ng/mL, respectively (p=0.314). Average GSN level for revision patients was 53,294±19,868 ng/mL, significantly higher than cadaver well-functioning TKAs (p=0.006). The patient with the highest level of GSN at time of revision surgery showed significant metallosis at the time of surgery.