Rotating Hinge Knee Versus Constrained Condylar Knee Revision: A Single Centre, Retrospective Comparative Study

Area of Science:

• Orthopaedic Surgery
• Biomedical Engineering

Background:

• Revision total knee arthroplasty often involves complex cases requiring specialized implants.
• Rotating hinge implants (RHK) and constrained condylar implants (CCK) are commonly used, with prior assumptions of differing outcomes.

Purpose of the Study:

• To compare patient-reported outcome measures (PROMs), complication rates, and implant survivorship between RHK and CCK in revision knee arthroplasty.
• To evaluate the long-term efficacy of these implants at a high-volume elective orthopaedic center.

Main Methods:

• A retrospective review of 108 patients undergoing revision knee arthroplasty with either CCK or RHK.
• Collection of PROMs (EQ5D, Oxford Knee Scores) pre-operatively and at one year post-operatively.
• Analysis of complication data and implant survival using bespoke database and National Joint Registry (NJR) data up to 12 years.

Main Results:

• No statistically significant difference was found in implant survival between RHK and CCK from two to 12 years post-operatively.
• Patient-reported outcome measures (PROMs) showed no significant difference between the two implant types.
• Complication rates were comparable between the rotating hinge implant and the constrained condylar implant groups.

Conclusions:

• Both RHK and CCK are viable and comparable options for revision knee arthroplasty.
• Implant survival and complication rates do not differ significantly between these two implant types.
• Further research via prospective randomized controlled trials is recommended to solidify these findings.