Electromyographic and gait analysis of forty-three patients after rotationplasty

Background: Rotationplasty is considered to be a treatment option for patie nts who have had a primary malignant bone tumor of the distal part of the f emur or the proximal part of the tibia, The present study was performed to evaluate the muscle activity, the kinetics (range of motion of the hip and knee joints), and the kinematics (joint moments) after rotationplasty and t o determine whether there was an association between these parameters and t he functional outcome. Methods: Forty-three patients who had been managed with rotationplasty for the treatment of a femoral or tibial bone tumor were evaluated clinically a nd functionally. The mean age (and standard deviation) at the time of follo w-up was 24.4 +/- 10.7 Sears (range, eight to sixty-eight years), the mean age at the time of the procedure was 17.8 +/- 10.2 Sears (range, seven to s ixty-three years), and the mean duration of follow-up was 6.7 +/- 4.9 years : (range, 0.7 to eighteen years), Instrumented gait and electromyographic a nalyses were performed. The qualitative data were compared with the functio nal outcome, which was determined with the functional evaluation score of t he Musculoskeletal Tumor Society. Results: g;ait analysis revealed a fairly normal walking pattern with a sli ght limp and a lateral lean of the trunk over the ipsilateral limb that led to a reduced joint moment in the hip (moment on involved side, 68 percent [compared with a control group]; moment on uninvolved side, 81 percent). Th e ranges of motion of the hips (uninvolved side, 42.0 +/- 8.2 degrees; invo lved side, 2.4 +/- 8.0 degrees) and the knees (uninvolved side, 59.7 +/- 5. 0 degrees; involved side [former ankle joint], 58.1 +/- 11.6 degrees) were symmetrical even though the knee-motion pattern of the involved limb indica ted a slightly reduced extensor mechanism in 51 percent (twenty-two) and a markedly reduced extensor mechanism in 35 percent (fifteen) of the forty-th ree patients. Electromyography revealed function of the muscles of the invo lved limb, with comparable amplitudes in the involved and uninvolved limbs. The leg muscles of the involved limb were active in the stance phase (the soleus and the lateral and medial heads of the gastrocnemius) and the swing phase (the peroneus longus and the tibialis anterior) according to their f unction in relation to the new knee joint. The patients had a good function al result, with a mean score of 23.9 +/- 2.7 of 30 points. With the numbers available for study, we could not Show the duration of follow-up to be rel ated to the overall outcome, but the age at the time of the operation:was r elated to the total functional score as well as to gait and walking ability (p < 0,05), Conclusions: The results of the electromyographic and gait analyses demonst rated good functional restoration of gait following rotationplasty.