Clinical and functional comparison of uni- and bicondylar sledge prostheses.

The aim of the present study was the evaluation of differences in clinical results, proprioceptive performance and gait in patients with unicondylar and bicondylar sledge prostheses of the knee. In a retrospective study, 17 patients with unicondylar sledge prostheses were compared with 15 patients with bicondylar sledge prostheses. Clinical examination was rated using HSS, Knee Society, and patellar scores and a visual analogue scale for pain. Proprioceptive performance was examined using sway measurements during single leg stance on a force platform. In addition, the patients underwent 3-D gait analysis including measurements of ground reaction forces and surface electromyographic (EMG) investigation of the lower extremity. Comparing both patient groups in clinical scores, gait, EMG and proprioception, no significant differences were found. Implantation of bicondylar sledge prostheses retaining both cruciate ligaments achieves functional results as good as unicompartmental arthroplasty. The presented results might encourage future research on new models of total joint replacement with preservation of both cruciate ligaments.

Proprioceptive function, clinical results, and quality of life after unicondylar sledge prostheses.

OBJECTIVE: Evaluation of proprioceptive performance and quality of life after implantation of unicondylar sledge knee prostheses in comparison with normal control subjects. DESIGN: A total of 17 patients were examined after implantation of unicondylar sledge prostheses. Clinical examination was performed, quality of life was assessed, and proprioceptive performance was examined. A total of 11 healthy subjects of comparable age served as a control group. RESULTS: Clinical results of both groups differed significantly in all categories. Quality-of-life assessment differed only in the following items: physical functioning, role limitation caused by physical problems, and bodily pain. Other than angle reproduction at 15 degrees, no significant differences in proprioceptive testing, neither sway measurement nor angle reproduction, were found. Statistical analysis revealed no correlation between clinical scores and proprioceptive results. CONCLUSIONS: In comparison with normal control subjects of comparable age, the implantation of unicondylar sledge prostheses does not result in proprioceptive deficits. Except for physical functioning, role limitations caused by physical problems and bodily pain, most aspects of quality of life do not differ between patients and control subjects, although the patients' clinical results were significantly lower than the controls.

Quality of life and gait after unicondylar knee prosthesis are inferior to age-matched control subjects.

OBJECTIVE: Evaluation of quality of life, gait pattern, and muscle activity after implantation of unicondylar sledge prostheses in comparison with control group. DESIGN: A total of 17 patients were examined at an average follow-up of 21.5 mo after implantation of unicondylar sledge prostheses. In addition to clinical evaluation with different scores, our patients underwent three-dimensional gait analysis and surface electromyographic investigation of the lower limb and quality-of-life assessment using the Short Form-36 health questionnaire. The control group consisted of 11 healthy subjects. RESULTS: Statistical analysis showed significantly lower results for the patient group in the Hospital for Special Surgery score, the Knee Society score, the patella score, and the Visual Analog Scale for pain. In quality of life, significant differences could be found for the following items: physical functioning, role limitation because of physical problems, and bodily pain. Electromyographic activities during gait were significantly lower in the patient group, except for the rectus femoris and the tibialis anterior. Regarding gait analysis, the variables for ground reaction forces and stride length differed significantly, whereas maximum knee extension and flexion did not. CONCLUSIONS: Unicondylar knee replacement has failed to restore functional capabilities, quality of life, gait pattern, and muscle activity compared with healthy subjects of the same age. The assumption that unicondylar sledge prostheses preserve normal joint function must be questioned.

Muscle strength in patients with unicompartmental arthroplasty.

OBJECTIVE: The aim of the current study was to evaluate the isokinetic strength of the knee in patients with unicondylar prostheses, to compare these results with healthy control subjects of the same age, and to correlate these results with clinical scores. DESIGN: Seventeen patients were examined an average of 21.5 mos after surgery. Clinical examination was done using the Hospital for Special Surgery, Knee Society, and patellar scores and a visual analog scale for pain. Quality of life was assessed by the Short Form 36 Health Questionnaire. Isokinetic evaluation of knee extensor and flexor muscles was done using a Cybex 6000 dynamometer at angular velocities of 60 and 180 degrees/sec. Eleven healthy subjects of comparable age served as a control group. RESULTS: Clinical results differed significantly in all categories. Quality of life differed only in the items of physical functioning, role limitation because of physical problems, and bodily pain. Isokinetic strength in patients showed a loss of torque of approximately 30% in extension and flexion at 60 and 180 degrees/sec compared with the control group. The flexion and extension ratio and the angles of maximum torque did not differ between the groups. CONCLUSION: In comparison with healthy control subjects, persons with an implanted unilateral sledge prosthesis have strength deficits in extension and flexion. A deficit of the extensor muscles, as it has been described previously for patients with a total knee arthroplasty, could not be found.