Do Intact Collateral Ligaments Play a Role in the Overall Clinical and Radiological Results of Rotating Hinge Knee Arthroplasties?

Background: Rotating hinge knee arthroplasty (RHKA) implants are often utilized as a salvage procedure in cases where bone stock is compromised. The aim of this retrospective study was to investigate whether residual collateral ligament integrity affects functional and radiographic outcomes in patients undergoing revision surgery with RHKA.

Methods: Patients treated with RHKA between 2011 and 2021 were eligible. Inclusion criteria were patients who had undergone an RHKA as a revision or a primary procedure, had complete radiological and clinical data, and had a minimum follow-up of 2 years. There were 79 knees that were included. Patients were evaluated with standing radiographs and two-dimensional multi-acquisition variable-resonance imaging combination selective (MAVRIC) magnetic resonance imaging (MRI) sequences to assess ligament integrity. Range of motion (ROM), Visual Analog Scale (VAS), Knee Society Scores (KSS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were recorded. The mean age was 66 years (range, 39 to 79), and the mean follow-up was 54.6 months (approximately 4.5 years). The integrity of the collateral was successfully determined by the magnetic resonance imaging scans and patients were divided into three groups: those who had both collateral ligaments (n = 53), isolated medial collateral ligament damage (n = 14), and those who had both collateral ligaments damaged (n = 12).

Results: No significant difference was observed between the groups with regard to both radiological data and clinical scores (P > 0.05). KSS, KSS-F, and Western Ontario and McMaster Universities Osteoarthritis Index function scores at the last follow-up were significantly higher in patients treated for secondary osteoarthritis (complex primaries).

Conclusions: No significant difference in functional outcomes was detected in patients treated with RHKA, independent of collateral ligament integrity, at an average of 54 months postoperatively. When an RHKA is indicated as the first treatment option, results are more satisfactory in comparison to revision cases.