Femoral lengthening might impair physical function and lead to structural changes in adjacent joints: 10 patients with 27 to 34 years' follow-up.

Background and purpose - Literature describing long-term functional outcome and osteoarthritis (OA) in adjacent joints after femoral lengthening is rare. We evaluated physical function and the presence of radiographic OA in adjacent joints in 10 patients ≥ 27 years after femoral lengthening.Patients and methods - We conducted a cross-sectional study of 10 patients treated by unilateral femoral lengthening. Follow-up was between 27 and 34 years. Physical function was evaluated by the 30-second sit-to-stand (30sSTS) and a stair test and was compared with reference values. 4 single-legged hop tests were used to assess difference in physical function between the lengthened and contralateral limb. Radiographic OA was evaluated by joint space width (JSW) and Kellgren and Lawrence (KL) classification.Results - The patients scored worse compared with reference values on the 30sSTS and stair test, and worse on the lengthened limb on the single- and triple-hop test. Radiographic OA was found in the hip or knee in the lengthened limb in 3 of 10 patients based on JSW and 4 of 10 based on KL. No radiographic OA was found in unlengthened limbs.Interpretation - Our results showed impaired physical function both in general and of the lengthened limb. Additionally, we found a possible association between femoral lengthening and radiographic OA in adjacent joints in the long term. However, the sample size of the current study is small.