[Minimally invasive unicondylar knee replacement with computer navigation]. / Minimal-invasive navigiert implantierte unikondyläre Knieendoprothese.

METHODS: From January 2003 to July 2005 a total of 50 St Georg medial knee monosleds with metal-backed tibial components in stably seated form and Uniglide prostheses (Alphanorm/Corin) with mobile bearing onlays were implanted in minimally invasive operations. Postoperatively the alignment-especially of the tibial components-was investigated, to check whether we had achieved the dorsal slope we had been aiming at, i.e. 5-7 degrees , in the region of these knee replacements. RESULTS: Before surgery there were initial malalignments of up to 10 degrees varus and 3 degrees valgus. All leg axes were restored to between -3 degrees and +3 degrees . The desired dorsal slope of 5-7 degrees for the knee monosleds relative to the tibial component was realized, the average slope being 5.3 degrees . The a-p alignment of the tibial component and of the femoral component was correct. CONCLUSIONS: Use of the navigation system leads to more accurate and reproducible results in terms of tibial dorsal slope, which is extremely important when these monosleds are used. Overcorrection of the leg axis is generally avoided. The use of too-high medial onlays is also reliably avoided by the navigation system's monitoring of the level of the cut.

Percutaneous lumbar discectomy in the treatment of lumbar discitis.

Lumbar disc infection, either after surgical discectomy or caused by haematogenous spread from other infection sources, is a severe complication. Specific antibiotic treatment has to be started as soon as possible to obtain satisfactory results in conservative treatment or operative fusion. The aim of this study was to analyse 16 cases of lumbar disc infection, treated with percutaneous lumbar discectomy (PLD) to obtain adequate amounts of tissue for histological examination and microbial culture. Between 1990 and 1994, 26 patients with vertebral osteomyelitis were treated. Sixteen patients, with an average age of 41.4 years (range 14-59 years), underwent a diagnostic PLD. Eight of them showed only moderate changes on computed tomograms (CT scans) and magnetic resonance (MR) images in the initial stages of the disease. The other eight showed more or less extensive osteolytic lesions of one or both vertebral bodies adjacent to the involved disc. The histology results showed non-specific discitis in nine patients and tuberculosis in one. In two patients an open biopsy had been performed, which showed non-specific discitis. Microbiological analysis revealed specific infection in 45% of the patients. These patients received a specific antibiotic treatment after antibiogram for an average of 33 days. Only three patients were treated surgically, with evacuation of the disc space and interbody fusion; the whole group received a spondylitis brace. All patients obtained satisfactory clinical results at the last follow-up regarding pain, mobility and spontaneous fusion of the involved disc space. In conclusion, PLD is a very helpful minimally invasive procedure in conservative treatment of lumbar discitis.

Verification of the position of pedicle screws in lumbar spinal fusion.

Medial or lateral pedicle screw penetration with the potential to affect neural structures in a wellknown and frequent problem associated with posterior spinal fusion. We evaluated the placement of pedicle screws (n = 141) in 36 patients following posterior lumbar spinal fusion with Socon or Kluger instrumentation via a lateral transpedicular approach. The examination was based on CT and MR images performed after removal of the instrumentation, on average 1 year after implantation. We found seven pedicle screws with lateral cortical penetration of the pedicle and five screws with medial cortical penetration of the pedicle (8.5% pedicle penetration overall). No severe radicular complications accompanied these pedicle penetrations. The mean insertion angles of the pedicle screws at the L4 level were 22.6 degrees and 23.1 degrees for the left and the right side, respectively. At the L5 level the mean insertion angle was 20.5 degrees on the left side and 21.5 degrees on the right, and at the S1 level the mean angle was 16.2 degrees on the left and 15.2 degrees on the right. The results of this study indicate that the lateral transpedicular approach is a safe procedure for pedicle screw insertion.

Intraarticular autogenous bone grafting in recurrent shoulder dislocations.

In a reexamination, 24 young soldiers who had been operated on using a new method of screwing an autogenous bone graft into the glenoid rim in cases of recurrent dislocation of the shoulder joint were investigated. A major functional problem is the reduced lateral rotation, even by using other procedures for operative treatment like Eden-Hybinette or Putti-Platt. This reduction of shoulder movement results in problems using the affected arm during sporting activities or military duties. There has been an excellent result without any redislocation in a follow through of 6 to 42 months and more than 90% satisfied patients, with only a very low rate of reduction of lateral rotations about 10 degrees using this procedure. The X-rays of all the patients, reinvestigated, showed a complete healing of the bone grafts into the glenoid rim and correct position of AO-screws.