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Background The surface texture, localization, and magnitude of the surface material applied to the femoral stem can facilitate bone ingrowth and influence the survival of total hip arthroplasties. Clinical and radiographic studies have shown superior bone ingrowth in proximally porous-coated stems with a diaphyseal grit-blasted surface in comparison to a smooth diaphyseal surface. Surface textures—especially porous surface material—have been suggested to have a sealing effect against migration of polyethylene debris along the implant-bone interface and to reduce the inflammatory response, leading to a prolonged implant survival. Patients and methods Between 2004 and 2006, we conducted a randomized, controlled trial (RCT) involving 50 patients with non-inflammatory arthritis. They received either a distally tapered, extended coated stem or a straight, proximally coated stem. During surgery, tantalum markers were inserted into the greater and lesser trochanter. Implant migration was evaluated at 3, 12, and ...

Background and purpose An increasing number of lumbar fusions are performed using allograft to avoid donor-site pain. In elderly patients, fusion potential is reduced and the patient may need supplementary stability to achieve a solid fusion if allograft is used. We investigated the effect of instrumentation in lumbar spinal fusion performed with fresh frozen allograft in elderly patients. Methods 94 patients, mean age 70 (60–88) years, who underwent posterolateral spinal fusion either non-instrumented (51 patients) or instrumented (43 patients) were followed for 2–7 years. Functional outcome was assessed with the Dallas pain questionnaire (DPQ), the low back pain rating scale pain index (LBPRS), and SF-36. Fusion was assessed using plain radiographs. Results Instrumented patients had statistically significantly better outcome scores in 6 of 7 parameters. Fusion rate was higher in the instrumented group (81% vs. 68%, p = 0.1). Solid fusion was associated with a better functional outcome at follow-up (significant in 2 of 7 parameters). 15 patients (6 in the non-instrumented group and 9 in the instrumented group) had repeated lumbar surgery after their initial fusion procedure. Functional outcome was poorer in the group with additional spine surgeries (significant in 4 of 7 parameters). Interpretation Superior outcomes after lumbar spinal fusion in elderly patients can be achieved by use of instrumentation in selected patients. Outcome was better in patients in which a solid fusion was obtained. Instrumentation was associated with a larger number of additional surgeries, which resulted in a lesser degree of improvement. Instrumentation should not be discarded just because of the age of the patient.

UNLABELLED Chronic low back pain (CLBP) has become one of the most common causes of disability in adults under 45 years of age and is consequently one of the most common reasons for early retirement in industrialised societies. Accordingly, CLBP represents an expensive drain on society's resources and is a very challenging area for which a consensus for rational therapy is yet to be established. The spinal fusion procedure was introduced as a treatment option for CLBP more than 70 years ago. However, few areas of spinal surgery have caused so much controversy as spinal fusion. The literature reveals divergent opinions about when fusion is indicated and how it should be performed. Furthermore, the significance of the role of postoperative rehabilitation following spinal fusion may be underestimated. There exists no consensus on the design of a program specific for rehabilitation. Ideally, for any given surgical procedure, it should be possible to identify not only possible complications relative to a surgical procedure, but also what symptoms may be expected, and what pain behaviour may be expected of a particular patient. The overall aims of the current studies were: 1) to introduce patient-based functional outcome evaluation into spinal fusion treatment; 2) to evaluate radiological assessment of different spinal fusion procedures; 3) to investigate the effect of titanium versus stainless steel pedicle screws on mechanical fixation and bone ingrowth in lumbar spinal fusion; 4) to analyse the clinical and radiological outcome of different lumbar spinal fusion techniques; 5) to evaluate complications and re-operation rates following different surgical procedures; and 6) to analyse the effect of different rehabilitation strategies for lumbar spinal fusion patients. The present thesis comprises 9 studies: 2 clinical retrospective studies, 1 clinical prospective case/reference study, 5 clinical randomised prospective studies and 1 animal study (Mini-pigs). In total, 594 patients were included in the investigation from 1979 to 1999. Each had prior to inclusion at least 2 years of CLBP and had therefore been subjected to most of the conservative treatment leg pain, due to localized isthmic spondylolisthesis grades I-II or primary or secondary degeneration. PATIENT-BASED FUNCTIONAL OUTCOME: Patients' self-reported parameters should include the impact of CLBP on daily activity, work and leisure time activities, anxiety/depression, social interests and intensity of back and leg pain. Between 1993 and 2003 approximately 1400 lumbar spinal fusion patients completed the Dallas Pain Questionnaire under prospective design studies. In 1996, the Low Back Pain Rating scale was added to the standard questionnaire packet distributed among spinal fusion patients. In our experience, these tools are valid instruments for clinical assessment of candidates for spinal fusion procedures. RADIOLOGICAL ASSESSMENT It is extremely difficult to interpret radiographs of both lumbar posterolateral fusion and anterior interbody fusion. Plain radiographs are clearly not the perfect media for analysis of spinal fusion, but until new and better diagnostic methods are available for clinical use, radiographs will remain the golden standard. Therefore, the development of a detailed reliable radiographic classification system is highly desirable. The classification used in the present thesis for the evaluation of posteroalteral spinal fusion, both with and without instrumentation, demonstrated good interobserver and intraobserver agreement. The classification showed acceptable reliability and may be one way to improve interstudy and intrastudy correlation of radiologic outcomes after posterolateral spinal fusion. Radiology-based evaluation of anterior lumbar interbody fusion is further complicated when cages are employed. The use of different cage designs and materials makes it almost impossible to establish a standard radiological classification system for anterior fusions. BONE-SCREW INTERFACE: Mechanical binding at the bone-screw interface was significantly greater for titanium pedicle screws than it was for stainless steel. This could be explained by the fact that the titanium screws had superior bone on-growth. There was no correlation between screw removal torques and pull-out strength. Clinically, the use of titanium and titanium-alloy pedicle screws may be preferable for osteoporotic patients and those with decreased osteogenesis. OUTCOME The present series of studies observed significant long-term functional improvement for approximately 70% of patients who had undergone lumbar spinal fusion procedure. Solid fusion as determined from radiographs ranged from 52% to 92% depending on the choice of surgical procedure. The choice of surgical procedure should relate to the diagnosis, as patients with isthmic spondylolisthesis (Grades I and II) are best served with posterolateral fusion without instrumentation, and patients with disc degeneration seem to gain most from instrumented posterolateral fusion or circumferential fusion. COMPLICATIONS The number of perioperative complications increased with the use of pedicle screw systems to support posterolateral fusions and increased further with the use of circumferential fusions. There was no significant association between outcome result and perioperative complications. The risk of reoperation within 2 years after the spinal fusion procedure was, however, significantly lower for those who had received circumferential fusion in comparison to posterolateral fusion with instrumentation. Furthermore, the risk of non-union was found to be significantly lower for patients who had received circumferential fusion as compared to posterolateral fusion with and without instrumentation. The complications of sexual dysfunction and fusion at non-intended levels were found to be significant but without influence on the overall outcome. REHABILITATION The patients in the Back-cafe group performed a succession of many daily tasks significantly better and moreover had less pain compared with both the Video and Training groups 2 years after lumbar spinal fusion. The Video group had significantly greater treatment demands outside the hospital system. This study demonstrates the importance of the inclusion of coping schemes and questions the role of intensive exercises in a rehabilitation program for spinal fusion patients.

In vitro cultures of human primary osteoblast-like cells provide a model for studying cellular mechanisms associated with human bone biology. We investigated in vitro osteoblast-like cell metabolism as a method for predicting the occurrence of spinal fusion in the individual patient. A bone biopsy was taken from the iliac crest of 50 patients, median age 49 (23-77) years, who were undergoing lumbar spine fusion. First-passage osteoblast-like cells were established by the bone-tissue-explant method. We then estimated 3H-thymidine incorporation, alkaline phosphatase activity and procollagen I production. Fusion rates were evaluated at the 1-year follow-up. Primary human osteoblast-like cell cultures showed an age-dependent decline in their capacity for cellular outgrowth and expression of alkaline phosphatase, which suggested a useful biological response pattern of the osteoblast culture. However, such cultures were unsatisfactory as an in vitro tool for predicting fusion capacity.

In a prospective randomized study, we evaluated the risk of lumbar posterolateral spinal fusion at an unintended level due to bone graft migration. 130 patients underwent fusion supplemented by pedicle screw fixation (Cotrell-Dubousset, 64 patients) or uninstrumented fusion (66 patients). This was assessed by two independent observers on antero-posterior, and lateral radiographs taken 1 year after surgery. All patients had ben operated on at the preoperatively planned levels. Both observers agreed that fusion had taken place at an unintended level in 19 cases (14%). We found a tendency towards a higher risk of this "complication" when using supplementary pedicle screw fixation. The functional outcome, assessed by the Dallas Pain Questionnaire and the Low Back Pain Rating scale, was similar in patients having fusion at an unintended level and in patients fused only at the intended levels. There was no difference between the two groups concerning reoperation rates, postoperative smoking or social status. We conclude that unintended fusion occurs and tends to be commoner with the use of pedicle screw instrumentation. However, this complication seems not to affect the functional outcome if fusion has taken place at the intended level.

In a series of 213 consecutive total hip replacements a.m. Lubinus, the clinical course after 72 revisions and 141 primary procedures was compared after 5 years. The revised THRs were uncemented Ring prostheses. Dislocation and peroperative fracture were more common in the revision group. Two failures because of aseptic loosening occurred in the revision group and 3 in the control group. No excisional arthroplasty was required, and no infections occurred. Radiographic evaluation of prosthetic positioning, component loosening, calcar resorption, and paraarticular ossification disclosed only slightly inferior results in the revision group. Clinically, the revised cases were not inferior to the primary ones. Revision of the uncemented hip seems less difficult than of the cemented hip.