Rotating Hinge Implants for Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis of 6,554 Knees

Implant design improvements and expanded indications for total knee arthroplasty (TKA) have led to the increasing use of rotating hinge implants in primary TKA. Revisions following primary rotating hinge total knee arthroplasty (RH-TKA) are complex and often cause major patient morbidity. This review amalgamated survivorship data on primary RH-TKAs, causes for revision, and patient-reported outcome measures (PROMs).

MEDLINE, EMBASE, and CENTRAL were searched for studies assessing implant survivorship following primary RH-TKAs. Secondary outcomes included causes for revision surgery, type of revision surgery, and PROMs. Survivorship at less than five years, five to less than 10 years, and 10 to 15 years was assessed using meta-analysis. There were 31 studies (6,554 knees) included for final analysis (median age, 70 years; median body mass index, 28.0), with 13 unique implants utilized.

Less than 5-year, five to less than 10-year, and 10- to 15-year survivorships were 93.8% (95% confidence interval [CI], 90.5 to 96.0), 91.5% (95% CI, 88.6 to 93.6), and 86.3% (95% CI: 82.2 to 89.5), respectively. Survivorship in the 10 to 15-year group was significantly lower than the less than 5-year (P = 0.002) and five to less than 10-year (P = 0.023) groups. The overall incidence of complications requiring revision was 7.4% (range, 0 to 36.4), with the most common causes being infection (2.6%), aseptic loosening (1.2%), and periprosthetic fracture (1.1%). Patients mostly attained the substantial clinical benefit of evaluated PROMs, irrespective of indication.

Based on observational data, the use of rotating-hinge implants in primary TKA leads to favorable survivorship at less than five years and at five to less than 10 years postoperatively in appropriately selected patients. Limited evidence exists pertaining to risk factors for revision surgery following primary RH-TKAs. Future studies may also consider implant- or indication-specific analyses to maximize the generalizability of findings.

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