In the past orthopaedic surgeons have kept their hands off from spontaneous or artificial fused hips, because those hips were painless, and the result of any further surgical procedure would be doubtful. In our days the need for conversion hip arthroplasty became a demand of patients having a better quality of life. In this paper we report on our results and the perioperative complications following conversion surgery. Between 1993 and 2002 thirty-one hips of twentyfive patients (18 males, 7 females) were converted from totally stiff hip to total hip arthroplasty in the two most frequented orthopaedic hospitals in Budapest, Hungary (Semmelweis University, Medical School, Dept. of Orthopaedics &
Hospital of Hospitaller Brothers of St.John of God, Dept. of Orthopaedics). The mean age of the patients was 47.2 years (ranging from 14 to 75 years) at the time of surgery. The average follow up was 50.7 months (2–176). At our 25 patients the hips became stiff 15.7 years ago as an average (3–61). Spontaneous fusion occured in 14 cases due to Bechterews disease (spondylitis ankylopoetica). In 4 cases fused hips were converted following arthrodesis procedures. There was no significant difference between each groups, spontaneous ankylosis and surgical fusion were similar, they were evaluated as stiff hips on the same way. The indication for surgery was in most cases a painful lumbar spine or osteoarthritic knee joint on the ipsilateral side. The surrounding joints are obviously overloaded and overused because of the stiff hip joint, even though if the hip is painless. 27 cemented and 4 uncemented hip prostheses were implanted. The mean duration of conversion arthroplasties was 110 minutes, the perioperative blood loss was 1019 ml. Additional surgical procedures may be used, like intertrochanteric wedge resection, osteotomy of greater trochanter, muscle release from the iliac bone, tenotomy of the hip adductors or knee flexors. The Harris Hip Score increased significantly from 34.2 to 81.3 (p<
0.01). The leg length discrepancy decreased from 4.0 cm to 1.2 cm, the difference of thigh circumference changed from 4.3 cm to 2.7 cm, all results as an average. Trendelenburgs gait was detected at 25 hips pre-op, and at 5 hips at the time of follow up. Five cases were reoperated due to haematoma formation, there was one prosthesis disclocation and one early septic complication. Based upon the good clinical results at the follow up, we recommend to change the orthopaedic surgeons’ mind considering conversion arthroplasties. The surgical procedure can be performed securely, but it is technically challenging for each surgeon. The intraoperative use of fluoroscopy and preoperative planning are mandatory in conversion arthroplasty. Conversion arthroplasty is performed prior to severe degenerative changes in the surrounding joints.
It has been shown that the bone, nerve, tendon, and muscle can generate new tissue when a leg is lengthened. In this study we have examined the muscles to see whether the proliferative response occurs uniformly along the fibres or whether it is a disproportionate occurrence, and also to see whether the muscles of animals of different age responded differently. In five adult (more than 25 weeks) and five young (8 to 9 weeks) New Zealand White rabbits, a mid-diaphyseal tibial osteotomy was created and stabilised with an Orthofix (M-100) external fixator. After seven days, lengthening was carried out at a rate of 1.6 mm/day until a 20% increase in the tibial length had occurred. One hour prior to sacrifice, all of the animals were injected with bromodeoxyridine (BrdUrd, 40mg/kg). Proliferative response of muscle tissue was assessed by measuring the positive staining index (PSI) of BrdUrd in a two-step indirect immunohistochemistry using the monoclonal antibody Bu20a. We accomplished this staining in transverse sections (between the proximal and middle third, and between the middle and distal third of the muscle belly) and in longitudinal sections along the proximal, middle and distal third of the myotendinous junction (MTJ) of the lengthened flexor digitorum longus muscle belly. The opposite limb was used as a control for each animal. All of the muscles showed a proliferative response that was significantly higher on the experimental side. There was no difference between the PSI of the proximal transverse sections and the distal transverse sections. The young animals demonstrated significantly increased PSI in all sections compared with the adult animals (immature distal transverse section PSI: 4.91%; mature distal transverse section PSI: 1.67%). The PSI of the longitudinal sections of MTJ showed significantly higher values than in the muscle belly (PSI at the MTJ in adults: 5.23%; PSI at the MTJ in the young: 13.2 %). The PSI result was increased at the distal third of the MTJ in mature and immature rabbits (p0.05). The muscles show a proliferative response to elongation forming new muscle tissue. The proliferative reaction to lengthening is far greater in the muscles of growing animals compared to adults. The myotendinous junction demonstrates much more intensive proliferative activity than the muscle belly. The distal third of the myotendinous junction shows the highest PSI results. The results of this study help to interpret the results of the animal model for clinical studies and also indicate an advantage in carrying out lengthening on young individuals.
