ABSTRACT
INTRODUCTION: Accurate positioning of components in total knee arthroplasty (TKA) is essential to a satisfactory outcome. Significant malrotation may lead to chronic pain, stiffness, and dysfunction. This study aims to quantify improvements in functional outcomes following revision surgery for malrotation of either one or both components in TKA versus revision for aseptic loosening. METHODS: This was a retrospective review of TKAs that matched and compared the two-year functional outcomes of the malrotation group to a functionally similar aseptic loosening group. Functional outcomes were compared between groups using Short Form (SF-12), Western Ontario and McMaster University Osteoarthritis Index (WOMAC), and Knee Society Functional Score (KSFS). Student t-tests and chi-squared or Fisher's tests were used for statistical analysis. RESULTS: Of the patients revised, 24 had malrotation and 57 had aseptic loosening. A total of 16 femoral and 17 tibial components were revised for malrotation. All 16 femoral components were internally malrotated (mean -4.8 ± 4.1 degrees; range, -0.5 to -16.6). Of the tibial components, 15 were internally malrotated, (mean -9.5 ± 6.6 degrees; range, -2.2 to -23.5) and 2 were externally malrotated (mean 4.6 ± 2.1 degrees; range, 3.1 to 6.0). All functional outcome measures significantly improved comparably within both groups preoperatively to 24 months postoperatively. At 24 months, functional outcome measures were comparable between the groups and WOMAC function scores were significantly higher in the malrotation group. CONCLUSION: Revision TKA for malrotation can yield clinically and statistically significant functional improvements, similar in magnitude to those seen following revision TKA for aseptic loosening. LEVEL OF EVIDENCE: Level III.
ABSTRACT
BACKGROUND: Tourniquet use in total knee arthroplasty (TKA) remains controversial. While widely studied, any temporal effects on pain and opioid utilization have not been investigated. We hypothesized that postoperative opioid utilization increases with increasing tourniquet times in TKA. METHODS: We retrospectively reviewed 1110 TKAs by three arthroplasty surgeons from October 2016 through September 2019. Exclusion criteria included ambulatory surgery, undocumented tourniquet times, simultaneous bilateral TKA, and diagnoses other than osteoarthritis, inflammatory arthritis, or osteonecrosis. Postoperative opioid medications were converted to daily morphine milligram equivalents (MME/day). Secondary outcomes included range of motion (ROM) at 1-month, 3-month, and 1-year visits as well as patient reported outcomes measures (PROMs) at 3 and 12 months. RESULTS: Nine-hundred and eleven patients were included and stratified based on tourniquet use. Three-hundred and four patients were assigned to a "No Use" group (≤10'); 138 patients to "Low Use" (11-60'); 177 patients to "Medium Use" (61-90'); and 292 patients to "Prolonged Use" (91-120). Compared to No Use, MME/day was significantly increased with Medium Use (+7.676 MME/day, p = 0.001) and Prolonged Use (+12.44 MME/day, p =< 0.001). No significant differences were found between No Use and Low Use groups. Estimated blood loss (EBL) in Low Use and No Use groups was significantly increased compared to other groups (+120 mL, p < 0.001, +109 mL, p < 0.001 respectively). Post-operative ROM and complication rates were similar between groups at 1 year post-TKA. CONCLUSIONS: A threshold of 60 min of tourniquet time is associated with increased MME/day postoperatively compared to No Tourniquet. Functional and patient-reported outcomes are comparable between groups at 1 year follow-up.
