During a one-year period starting in October 2001, we analysed the intra-hospital cost of 102 primary elective total hip arthroplasty (THA) in a Belgian university hospital. Patients were treated according to age and general condition with an all cemented metal-poly THA (37), a uncemented cup and cemented metal-poly THA (40), an all uncemented ceramic-ceramic THA (18) or non-standard implants or combinations (7). On average patients stayed 14.4 days in the orthopaedic ward and intra-hospital cost was 9496 Euro (SD: 2178): 53.8% was related to hospitalisation, 21.3% to implants and material, 7.7% to surgery and 4.1% to anaesthesia. A multiple regression analysis was performed to identify possible influencing factors for intra-hospital cost and stay (pre-operative hip function, general health and dwelling as well as implant choice and intra-hospital complications). Overall, only the occurrence of complications during hospitalisation had a significant regression coefficient. In total 14 patients (13.7%) suffered at least one complication during hospitalization (dislocation: 4.9%, heamatoma or superficial infection: 2%, trochanter fracture: 1%, thrombosis with pulmonary embolism: 1%, general complications: 6.9%). This resulted in a significant higher cost (11823 versus 9125 Euro) and hospital stay (19.4 versus 13.6 days). For those patients who did not suffer complications, only implant choice and the place patients were discharged to had significant regression coefficients. The average implant cost for cemented metal-poly THA was 1444 Euro (16.1% of the total cost) compared to 2686 Euro (25.6% of the total cost) for uncemented ceramic-ceramic implants. Due to a chronic shortage of rehabilitation units in the Brussels region, discharged to these units led to both higher cost (10422 versus 9056 Euro) and longer hospital stay (16.5 versus 13.4 days). In the Belgian health insurance system, limitation of intra-hospital cost can best be achieved by shortening hospital stay after THA. This might include improved control of postoperative complications, faster rehabilitation programs and improved surgical techniques to reduce the needs for rehabilitation units and to allow earlier return to independency. Another option is to increase cost awareness regarding prolonged hospital stay of both, patients and medical staff.

Aims: Recurrence rate of low back pain is high because of the deþciency of Ôpostural and movement controlñ. The aim was to develop a clinically useful, valid and reproducible measure for postural control in a seated position. Accuracy to control equilibrium was measured in LBP patients. Methods: Postural control was investigated in 19 chronic aspeciþc LBP patients (20– 55years, mean 42,3y) and 20 healthy controls (20–55years, mean 37,8y). An unstable seated position was created by sitting on a balance board with a swing angle of 28¡. The chair and one foot were placed on the force platform of a Balance Master¨, testing four difþculty levels using arm movements and occlusion of vision. Outcome was measured using force plate data and visual observations. Results: A high test-retest reproducibility was measured for the low back pain patients (87.5%) but not for the healthy controls (32.5%). Discriminant analysis of all variables divided the total group (n=39) with an accuracy 97.4% in the LBP group (n=19) and the controls (n=20). Patients show increased difþculty to maintain seated balance. Conclusions: Chronic LBPP could be recognized as having signiþcantly more difþculty to maintain control of seated balance These þndings were conþrmed during observation using a 5 point scale. Pro-prioception impairment in LBP patients can be documented in clinical practice through difþculty in sitting on a balance board.

Aims: To evaluate the inßuence of wobble board training on complaints and on the control of ankle motion in functionally unstable ankles during a sudden inversion in the standing position. Methods: 25 patients were randomly allocated to a training group (13 persons, 15 ankles), or to a control group (12 persons, 15 ankles). Patients were only included if they suffered invalidating disabilities following at least two ankle inversion trau-mañs followed by at least 6 weeks of rehabilitation. They were randomly allocated to a wobble board training group (6 weeks), or to a no intervention control group. Accelerometric and electromyographic analysis of functional control during a sudden ankle inversion of 50û in the standing position and a validated functional impairments index were used to assess efþcacy. Results: Trained patients with Òmedium latencyÒ reßexes (n= 5) showed signiþcantly earlier decelerations with the ankle displaying in a signiþcantly smaller inversion displacement (p< 0.05, power=0.96). Trained patients with Òshort latencyÒ reßexes (n= 10) showed no signiþcant change in inversion control. All trained patients showed signiþ cantly less impairments compared to the control group. Conclusions: These results support the treatment strategy that wobble board training should be included in the rehabilitation of functional ankle instability.