Total Knee Arthroplasty in the Stiff and Ankylosed Knee at a Mean Follow-Up of 16 Years.

BACKGROUND

Total knee arthroplasty (TKA) in patients who have stiff or ankylosed knees (range of motion [ROM] < 20°) presents technical challenges. Outcomes of TKA in this group of patients at follow-up greater than 12 years are under-reported. This study assesses the outcomes of TKA in this cohort at a mean follow-up of 16.3 years.

METHODS

This retrospective review of 109 patients (135 knees) who underwent TKA for stiff or ankylosed knees between 2000 and 2014 included cases from our previously published series, with a minimum follow-up of 10 years. There were 61 knees that were stiff in extension and 74 in flexion (SF). The mean follow-up duration was 16.3 years (range, 10 to 23). We assessed and compared Knee Society Score, Knee Society Functional Score, ROM, complications, revision rates, and implant survivorship between the two cohorts.

RESULTS

At final follow-up, mean Knee Society Score improved from 15.8 ± 6.3 to 72.8 ± 5.1, Knee Society Functional Score from 9.4 ± 3.6 to 62.9 ± 3.9, and ROM from 11.4° ± 5.9 to 89.2° ± 14.1 (P < 0.001). Complications occurred in 33 knees, with 17 requiring revision. The 10 and 15 years implant survival was 88.9, and 81.7% respectively. Postoperative ROM and maximum flexion did not differ significantly between the two groups. There was no significant difference in complications between the two groups, although residual flexion contractures and extensor lag were more common in the SF group. There were no significant differences in implant survival observed among various implant types, etiologies, or between stiff in extension and SF cohorts.

CONCLUSIONS

In patients who have stiff or ankylosed knees in flexion or extension, TKA results in substantial long-term improvements in ROM and function, with acceptable implant survivorship, despite a relatively high complication rate. Functional outcomes and complication rates were similar across stiffness types, etiologies, and implant designs in a follow-up of more than 16 years.