Computer-navigated revision total knee arthroplasty for failed unicompartmental knee arthroplasty.

The most frequent technical difficulty encountered at unicompartmental knee arthroplasty (UKA) revision to total knee arthroplasty (TKA) is filling in all bone defects. These bone defects can render difficult components positioning, mechanical axis restitution, and ligament balance assessment, which are the three most important parameters for successful TKA. We describe a computer-assisted technique which makes it possible to control these three parameters before removal of the implants that have caused the bone defects. Our study is based on a series of 20 cases, with a minimum follow-up of 2 years. The anatomical and clinical results were very satisfying and comparable to results of primary TKA. We recommend this computer-navigated technique, which is as simple as a primary TKA procedure.

[Total hip arthroplasty after hip arthrodesis performed for septic arthritis]. / Désarthrodèse-prothèse de hanche pour séquelle d'arthrite septique: apropos d'une série de 17 cas à 6 ans de recul.

PURPOSE OF THE STUDY: Revision total hip arthroplasty (THA) after hip arthrodesis is an uncommon and challenging operation. The task would appear to be even more difficult if the arthrodesis was performed because of septic arthritis due to the theoretical risk of recurrent infection. We report our fifteen-year experience. MATERIAL AND METHODS: This retrospective study concerned 17 procedures performed in 17 patients (11 women, 6 men) between 1988 and 2003 on 5 right and 12 left hips. All of the patients had arthrodesis for sepsis: eight subsequent to tuberculosis and nine subsequent to septic arthritis (Staphylococcus aureus). We examined the impact of the initial arthrodesis (surgical technique, position, leg length) on neighboring joints and indications for de-fusion. Mean age was 53 years (range 32-74) and on average, the patients had a fixed hip for 36 years (range 7-59). Mean follow-up was six years (range 11 months to 15 years). Revision surgery was performed via a posterolateral approach for 12 hips (nine trochanterotomies) and via an anterolateral approach for five hips for implantation of nine cemented implants, six press fit implants, and two hybrid implants (cemented cup and press fit stem). Clinical assessment at last follow-up noted pain, walking capacity and joint motion. Leg length discrepancy was measured and complications were noted. RESULTS: The position of the original arthrodesis was considered satisfactory (flexion 20 degrees , adduction 0-10 degrees , external rotation 0-20 degrees ) for eight hips; leg length discrepancy was 4 cm (2-8 cm). Neighboring joints involved concerned the lumbar spine in 15 patients, the ipsilateral knee in ten patients, the contralateral knee in eight and the contralateral hip in six. The decision to remove the arthrodesis was based on functional needs related to lumbar pain (n=6), the homolateral knee (n=10, limping and leg length discrepancy), or an operation on the ipsilateral knee. After surgery, 14 hips (83%) were free of pain with improvement of the lumbar pain and pain of the homolateral knee. Six patients walked without support but 16 still had a limp. Flexion was 78 degrees . Leg length discrepancy was 2.5 cm on average and seven patients had balanced limbs. The postoperative period was uneventful for 14 of 17 patients (one paresia of the common fibular nerve, one femoral phlebitis, one early infection). Six late complications were noted: nonunion of the greater trochanter (n=2), recurrent ankylosis (n=1) and loosening (n=3). DISCUSSION AND CONCLUSION: An earlier history of infection does not appear to be a contraindication for implantation of a total hip arthroplasty after hip arthrodesis. Despite the long recovery period and the modest gain in joint motion, 80% of patients were satisfied after having had a blocked hip for 36 years on average.

The wrist of the formula 1 driver.

OBJECTIVES: During formula 1 driving, repetitive cumulative trauma may provoke nerve disorders such as nerve compression syndrome as well as osteoligament injuries. A study based on interrogatory and clinical examination of 22 drivers was carried out during the 1998 formula 1 World Championship in order to better define the type and frequency of these lesions. METHODS: The questions investigated nervous symptoms, such as paraesthesia and diminishment of sensitivity, and osteoligamentous symptoms, such as pain, specifying the localisation (ulnar side, dorsal aspect of the wrist, snuff box) and the effect of the wrist position on the intensity of the pain. Clinical examination was carried out bilaterally and symmetrically. RESULTS: Fourteen of the 22 drivers reported symptoms. One suffered cramp in his hands at the end of each race and one described a typical forearm effort compartment syndrome. Six drivers had effort "osteoligamentous" symptoms: three scapholunate pain; one medial hypercompression of the wrist; two sequellae of a distal radius fracture. Seven reported nerve disorders: two effort carpal tunnel syndromes; one typical carpal tunnel syndrome; one effort cubital tunnel syndrome; three paraesthesia in all fingers at the end of a race, without any objective signs. CONCLUSIONS: This appears to be the first report of upper extremity disorders in competition drivers. The use of a wrist pad to reduce the effects of vibration may help to prevent trauma to the wrist in formula 1 drivers.

[An unusual anomaly : cervical spondylolysis in an adult]. / Une anomalie exceptionnelle: la spondylolyse cervicale chez l'adulte.

A case of spondylolysis with exceptional involvement of the cervical spine is reported. The lesion turned out to be a defect in the pars interarticularis of a cervical vertebra. Such cases generally involve the sixth vertebra. Spondylolysis is asymptomatic more often than not. Positive diagnosis is supported by an analysis of the anatomic structures on radiographs and CT-scans. Differential diagnoses include congenital lesion (articular dysplasia) is always found, there is no argument allowing the assertion that cervical spondylolysis is a congenital condition rather than secondary to stress fractures.

[Post-operative fractures: epidemiology, predisposing factors]. / Fractures à distance de l'arthroplastie : épidémiologie, facteurs favorisants.

The general predisposing factors are female sex and osteoporosis. The local predisposing factor is loosening of the stem.As expected type III fractures are more frequent in case of osteoporosis (notion of elasticity gap) and fractures type II and I in case of loosening (notion of bone stock).