ABSTRACT
BACKGROUND: Rotating hinge knee prostheses are indicated in revisions especially when major ligament laxity or substantial AP deformities are present. These situations make ligament balancing difficult with less constrained design implants. Despite its use for nearly 50 years, this type of prosthesis continues to have a poor reputation due to a high complication rate. HYPOTHESIS: Complications are frequent after this type of arthroplasty and the complication rate is similar in primary or revision arthroplasties. The objective of this study is to report the medium-term results of these implants and determine the eventual predictive factors of complications in order to refine operative indications. MATERIAL AND METHODS: In this retrospective study of patients operated on between 1998 and 2006, 85 Endo-Modell (Link) rotating hinge knee prostheses had been used in 61 females and 24 males. The mean age at surgery was 72.4 years (range, 32-92 years). Fifty-two arthroplasties were primary and 33 were revisions either for loosening (24) or deep infections (9). The mean follow-up was 36 months+/-22 (range, 0-75 months). RESULTS: Complications were observed in 24 patients (28.2%): nine deep infections, four patellar complications, and three cases of aseptic loosening. No significant difference was found between the primary arthroplasties and the revisions regarding all complication types. A significant relation was established between the occurrence of a complication and presence of several associated comorbidity factors (obesity, heart disease, diabetes, etc.). DISCUSSION: The use of this type of implant carries a high risk of complications, higher than the one pertaining to unconstrained design prostheses; this fact is noted irrespective of the surgical indication and other comparison elements. The leading criteria to poor functional results appear to be the indication (gonarthrosis with substantial ligament laxity at primary surgery) and the number of associated comorbidities. These prostheses should therefore be restricted to selected indications, notably in view of the fact that less constrained prostheses give superior outcomes. LEVEL OF EVIDENCE: Level IV. Retrospective therapeutic study.
