# Mid‐ to Long‐Term Follow‐Up Outcomes of Single Design Rotating Hinge Knee in Infected and Noninfected Revision Patients

## TL;DR

This study shows that rotating hinge knee prostheses work well for revision knee surgeries, even in infected cases, with similar long-term outcomes to non-infected cases.

## Contribution

The study provides mid- to long-term clinical and survivorship data for a single-design rotating hinge knee system in infected and noninfected revision TKA patients.

## Key findings

- Infection group had earlier symptom onset and shorter prosthesis lifespan compared to the noninfection group.
- Functional outcomes and 10-year survival rates were comparable between infected and noninfected groups.
- Coagulase-negative staphylococci and Staphylococcus aureus were the most common pathogens in infected cases.

## Abstract

Total knee arthroplasty (TKA) offers significant relief for advanced knee osteoarthritis. With an aging population, TKA procedures are increasing, leading to a higher demand for revision surgeries. Rotating‐hinge knee (RHK) prostheses have emerged as a solution for complex revisions, but the long‐term durability of RHK prostheses and their effectiveness in infection‐related revisions remain controversial. Therefore, this study aimed to evaluate the mid‐ to long‐term clinical and survivorship outcomes of a single‐design rotating hinge knee (SDRHK) system in revision TKA, comparing patients revised for infection with those revised for noninfectious causes.

This retrospective study analyzed 110 patients who underwent revision total knee arthroplasty (rTKA) with a SDRHK system from 2004 to 2023, with an average follow‐up of 11.3 years. Patients were divided into an infection group (n = 51) and a noninfection group (n = 59) for comparative analysis. Preoperative diagnostic arthrocentesis was performed to evaluate synovial cell count, leukocyte differential, and microorganisms. Functional outcomes were assessed using Hospital for Special Surgery (HSS) knee score, range of motion (ROM), and Knee Society Score (KSS). Study outcomes included prosthesis survival, mechanical failure, and complications. Data were analyzed using Kaplan–Meier survival analysis, t test, and χ
2 test, with statistical significance set at p ≤ 0.05.

The infection group experienced symptom onset significantly earlier than the noninfection group (18.8 vs. 50 months, p = 0.003), had a shorter initial prosthesis lifespan (32.7 vs. 66.8 months, p = 0.001), and underwent more surgeries before revision (2.6 vs. 1.6, p = 0.004). Microbiological analysis indicated that coagulase‐negative staphylococci and
Staphylococcus aureus
were the most commonly isolated pathogens. The 5‐ and 10‐year prosthesis survival rates in the infection group were 78.4% and 71%, respectively, while those in the noninfection group were 83.1% and 74.6%. At the latest follow‐up, survival rates for the two groups were 68.6% and 71.2%, showing similar outcomes. Functional scores in both groups improved postoperatively, with no significant differences in HSS, ROM, or KSS scores between the groups.

This study highlights the important value of RHK prostheses in the treatment of prosthetic joint infection (PJI) after TKA. Despite challenges such as earlier symptom onset, shorter prosthesis lifespan, and higher complication rates in the infection group, their functional outcomes and prosthesis survival rates were comparable to those of the noninfection group, further validating the effectiveness of RHK prostheses. These findings provide useful references for clinical management of PJI and underscore the importance of continued innovation in revision techniques.

RHK prostheses are effective for revision TKA in cases of infection, instability, or loosening after primary TKA, with mid‐ to long‐term follow‐up showing good functional recovery and high implant survival.