Abstract
Background: The argument presupposes that intra-operative soft tissue balance is associated with patient-reported outcome measures after total knee arthroplasty (TKA). Our aim was to assess the association between the extension-to-flexion gap and patients’ reported perception of knee joint function.Methods: This was a retrospective study of 60 cases of primary cruciate-retaining TKAs performed for the treatment of medial-compartment knee osteoarthritis, at a mean follow-up of 2.6 (range, 2.0–5.2) years. Knee perception was evaluated by asking patients whether they considered their knee joint as “natural” (grade I) or “artificial”, with or without restrictions (grades II–V). The following factors were compared between the two groups: age, sex, and the extension-to-flexion gap difference. A multiple logistic regression analysis was used to identify predictive factors of an artificial knee joint perception. A receiver operating characteristic curve analysis was used to identify cut-off values of predictive factors. Result: Compared to a natural knee joint perception (26 knees, 43%), an artificial perception (34 knees, 57%) was associated with a smaller gap difference at the distraction force of 20 lbf (p < .001), 30 lbf (p = .022), and 40 lbf (p = .038), a lower EuroQol 5-Dimension score (p = .029), and self-reported joint health (Knee injury and Osteoarthritis Outcome Score-Joint Replacement [KOOS-JR], p = .032). A gap difference <1.0 mm was a predictive of an artificial perception (odds ratio, 1.63; 95% confidence interval, 1.33–4.54; p < .001). A cut-off gap difference of 0.99 mm at 20 lbf predicted an artificial perception with a sensitivity of 81.5% and a specificity of 87.9%. Post-operative satisfaction (p < .001), KOOS-JR (p < .001), patient’s joint perception (p = .006), pain (p = .015), and EuroQol 5-Dimension (p = .032) differed between the two groups when the gap difference threshold was set to 1.0 mm.Conclusion: Careful balancing of soft tissue during TKA to achieve an extension-to-flexion gap ≥ 1.0 mm can improve patients’ perception of knee joint function and quality of life.
Predictive factors for effectiveness and safety of enoxaparin for total knee arthroplasty in aged Japanese patients: a retrospective review
