Background: Sacro-iliac (SI) joint is vertically oriented and subject to a large shear force on weight bearing. Gluteus maximus is strongly active when we experience an abrupt limb loading and need a stable SI joint. Suboptimal gluteus activity could disrupt weight transference and lead to low back pain as the body attempts compensation by recruiting biceps femoris, which could exert its influence through attachment to sacrotuberous ligament. A biomechanical model of SI joint dysfunction was proposed. The model was tested on a pilot study.

Methods: Two male volunteers participated in the study. One was a normal subject. The other had pain suggestive of SI origin. Electromyogram was recorded using pairs of disposable bipolar surface Ag/AgCl electrodes on the symptomatic side for the lumbar multifidus, gluteus maximus and biceps femoris muscles. Subjects were asked to walk in a straight line. Each test was taken three times for two full gait cycles. Two dimensional high speed video was used to capture data of walking motion. Raw electromyogram data was processed according to published protocols.

Results and discussion: Gluteus activation was poor in the symptomatic individual and failed to reach a peak in loading response. Biceps remained activated on terminal swing event with another peak activation in ipsilateral pre-swing event. Unlike normal volunteer, gluteus failed to show increased activity in terminal stance to pre swing events. The study showed a difference in gluteus maximus and biceps femoris activity in between the two volunteers. A larger study is planned to validate the model.

Arthroscopic surgery is a common intervention for osteoarthritis of the knee. However, the benefits from such an intervention are not clear. The purpose of the study was to perform a questionnaire survey of orthopaedic surgeons of Wales to analyse the practice of arthroscopy for osteoarthritic knee.

Over a three-month period, a postal survey was conducted of all hospital orthopaedic consultants in Wales. Of a total of 62 questions sent we received a reply of 37. 31 surgeons perform arthroscopic lavage or debride-ment. 4 surgeons perform arthroscopic surgery for symptomatic meniscal tear only. There was no defined protocol regarding the management. Early OA was the commonest indication (18). Arthroscopic lavage (17) was equally popular to lavage and debridement (16). 6 respondents like to perform the surgery themselves while the majority would allow a middle grade surgeon to operate with or without supervision. 26 surgeons felt that the results of the procedure are unpredictable, but still continued to perform it. Only 6 surgeons felt a continued relevance of the procedure.

Arthroscopic surgery is a commonly performed symptomatic treatment for arthritic knee. It bears a significant financial commitment. 266 arthroscopic knee surgery were performed annually in a district general hospital, of whom 115 were arthroscopic washout. Average cost of each operation is £1000. The physiological basis for arthroscopic washout is not clear. A majority of the Welsh surgeons have reservations about this procedure. In spite of evidence of limited usefulness, it is still performed widely.