INCIDENCE OF PERMANENT PREOPERATIVE FLEXION ON OUTCOME OF TOTAL KNEE ARTHROPLASTY.

Abstract

Purpose: One of the difficult problems during the implantation of a total knee prosthesis is the presence of preoperative stiffness or permanent flexion.The later is a sign of advanced stage degradation due to osteoarthritis or rheumatoid arthritis. We wanted to describe the technical specificities of a total knee arthroplasty (TKA) implanted in patients with permanent flexion and to analyse long-term outcome.

Material and methods: We studied a series of 826 posterior stabilised TKA (HLS) implanted since 1988 (followed prospectively since 1995). We defined three groups of patients according to the degree of preoperative flexion: group I (0°–10°), group II (11°–20°), and group III (> 20°). We evaluated the operative technique itself, then analysed long-term clinical and radiological outcome using the IKS scores.

Results: There was no significant difference in the objective or subjective clinical or radiological outcomes in the first two groups (I and II). Outcome appeared to be less satisfactory in patients with permanent flexion greater than 20°, but the statistical analysis was not feasible.

Discussion: This study enabled us to describe the specific preoperative planning and the operative steps necessary for patients with permanent flexion preoperatively. The results of our series do no enable distinction between the long-term results in patients with < 20° flexion. Beyond this level, techniques for bony or ligamentary release influence the results which are less satisfactory. Posterior stabilisation enables release of the posterior cruciate ligament in order to improve joint recovery.

Conclusion: Preoperative planning for TKA must of course take into account bony deformation, but also preoperative joint motion. In the event of permanent flexion, the operative technique must be adapted. This allows correct position of the implant and improved joint motion.