Muscle activation pattern and gait biomechanics after total knee replacement.

OBJECTIVE: The aim of this study is to evaluate residual muscle function abnormalities after total knee replacement, with respect to gait kinematics and kinetics. DESIGN: Longitudinal study on a follow-up of up to two years. BACKGROUND: Gait usually presents an excellent improvement after total knee replacement. Nevertheless, some kinematics and kinetics abnormalities persist even after a long period of time and they might have implications in long-term prosthesis failure. Additionally, lower limb muscle activity has not been sufficiently studied in the past directly by means of dynamic EMG. METHODS: Nine patients who had a posterior cruciate sparing total knee replacement design were evaluated by means of clinical assessment and gait analysis at the end of rehabilitation trials at six, twelve and twenty four months. EMG from trunk and lower limb muscles was registered and elaborated through a statistical detector for the on-off timing. RESULTS: Gait analysis showed a slow gait, with a "stiff knee gait pattern" and prolonged muscular co-contractions during stance. CONCLUSIONS: Knee kinematics and kinetics abnormalities during loading acceptance after total knee replacement are associated with co-contractions in muscular activation pattern. RELEVANCE: Gait pattern at two years after total knee replacement is deemed unphysiological, potentially dangerous for the implant duration in time and responsible for residual disability in patients. Muscular behavior during daily activities provides insight into the integration of the prosthetic biomechanics within the muscular-skeletal system. This information is of relevance to improve prosthetic design, rehabilitation programs and knee motor performance.

The opportunity of rehabilitation treatment in acetabular fractures treated by osteosynthesis.

Two groups of 24 patients each who had been submitted to osteosynthesis for the treatment of fracture of the acetabulum were evaluated. The first group was submitted to rehabilitation treatment according to the protocol used in the Division of Physiotherapy at the Rizzoli Institute; the second group did not use this protocol. Clinical-radiographic follow-ups were obtained after 1 month, 3 months, 6 months, and 1 year postsurgery. The results of the evaluations carried out showed the usefulness of specific physiokinesitherapy in obtaining more rapid and best possible functional recovery.

Does total hip arthroplasty mean sensorial and proprioceptive lesion? A clinical study.

Total hip arthroplasty means sacrificing the joint capsule and the mechanoreceptors contained therein. Recent neurophysiological experiences seem to redefine the sensorial and proprioceptive role of the joint capsule in favor of the activity of the muscular mechanoreceptors, particularly in the area of the coxofemoral joint. The authors have examined the sensorial lesion caused by total hip arthroplasty in a group of 20 patients. Clinical testing was conducted prior to surgery, 7 and 40 days later. The tests were aimed at exploring the perceptive and proprioceptive activity of the hip, and showed marked decrease in all of the receptorial activity one week after surgery. After 40 days perceptive function was completely recovered, as the scores for tests conducted were the same as those obtained prior to surgery: proprioceptive activity was instead considerably improved, with significant changes in most parts of the tests. The authors conclude by observing that total hip arthroplasty does not cause permanent lesion of the perception of joint movement; furthermore, renewed coxofemoral mechanics allow for a better proprioceptive response with strengthening of static and dynamic antigravitational reactions.

Electromagnetic fields in the treatment of postmenopausal osteoporosis: an experimental study conducted by densitometric, dry ash weight and metabolic analysis of bone tissue.

The authors conducted an experimental study on 32 female rats which had been castrated at 10 months of age in order to verify the ability of pulsating electromagnetic fields to prevent osteoporosis induced by surgical menopause. Two different values of intensity of PEMFs were used: 30 G and 70 G. After 4 months of treatment the following testing was done: monophotonic bone densitometry of the lumbar spine, quantitative measurement of the dry ash weight of the femurs, and hematochemical tests to evaluate bone metabolism. The experimental study showed that the PEMFs supplied at 30 Gauss were capable of slowing down the loss of bone mass, while the PEMFs supplied at 70 Gauss obstructed bone decay, providing values for Bone Mineral Density and dry ash weight which were very similar to those observed in the non-castrated control group. Hematochemical tests did not reveal significant variations between the two groups.

Rehabilitation treatment in cemented and cementless prostheses.

Rehabilitation after hip arthroplasty is aimed at improving the results obtained with surgery and allowing the elderly patient to resume a normal daily life as quickly as possible. The correct use of the prosthesis positively influences its duration. Full weight-bearing on the limb submitted to surgery is allowed at different times: days 7-8 if the prosthesis is cemented. When the prosthesis is cementless the proper time for full weight-bearing is established by the orthopaedist, and it is usually allowed on days 30-40. Walking initially makes use of a walker, followed by parallel, and finally antibrachial support.