Early micromovement of the Articular Surface Replacement (ASR) femoral component: two-year radiostereometry results.

Radiostereometric analysis (RSA) can detect early micromovement in unstable implant designs which are likely subsequently to have a high failure rate. In 2010, the Articular Surface Replacement (ASR) was withdrawn because of a high failure rate. In 19 ASR femoral components, the mean micromovement over the first two years after implantation was 0.107 mm (SD 0.513) laterally, 0.055 mm (SD 0.204) distally and 0.150 mm (SD 0.413) anteriorly. The mean backward tilt around the x-axis was -0.08° (SD 1.088), mean internal rotation was 0.165° (SD 0.924) and mean varus tilt 0.238° (SD 0.420). The baseline to two-year varus tilt was statistically significant from zero movement, but there was no significant movement from one year onwards. We conclude that the ASR femoral component achieves initial stability and that early migration is not the mode of failure for this resurfacing arthroplasty.

Changes in bone mineral density of the acetabulum, femoral neck and femoral shaft, after hip resurfacing and total hip replacement: two-year results from a randomised study.

It is accepted that resurfacing hip replacement preserves the bone mineral density (BMD) of the femur better than total hip replacement (THR). However, no studies have investigated any possible difference on the acetabular side. Between April 2007 and March 2009, 39 patients were randomised into two groups to receive either a resurfacing or a THR and were followed for two years. One patient's resurfacing subsequently failed, leaving 19 patients in each group. Resurfaced replacements maintained proximal femoral BMD and, compared with THR, had an increased bone mineral density in Gruen zones 2, 3, 6, and particularly zone 7, with a gain of 7.5% (95% confidence interval (CI) 2.6 to 12.5) compared with a loss of 14.6% (95% CI 7.6 to 21.6). Resurfacing replacements maintained the BMD of the medial femoral neck and increased that in the lateral zones between 12.8% (95% CI 4.3 to 21.4) and 25.9% (95% CI 7.1 to 44.6). On the acetabular side, BMD was similar in every zone at each point in time. The mean BMD of all acetabular regions in the resurfaced group was reduced to 96.2% (95% CI 93.7 to 98.6) and for the total hip replacement group to 97.6% (95% CI 93.7 to 101.5) (p = 0.4863). A mean total loss of 3.7% (95% CI 1.0 to 6.5) and 4.9% (95% CI 0.8 to 9.0) of BMD was found above the acetabular component in W1 and 10.2% (95% CI 0.9 to 19.4) and 9.1% (95% CI 3.8 to 14.4) medial to the implant in W2 for resurfaced replacements and THRs respectively. Resurfacing resulted in a mean loss of BMD of 6.7% (95% CI 0.7 to 12.7) in W3 but the BMD inferior to the acetabular component was maintained in both groups. These results suggest that the ability of a resurfacing hip replacement to preserve BMD only applies to the femoral side.

Influence of pre-operative bone mineral content of the proximal tibia on revision rate after uncemented knee arthroplasty.

Between 1986 and 1991, 106 patients (127 knees) underwent uncemented knee arthroplasty for osteoarthritis. There were 106 total knee arthroplasties and 21 medial unicompartmental knee arthroplasties. The arthroplasties were evaluated for aseptic loosening during the year 2000. For total arthroplasty we used 77 porous-coated anatomic prostheses and 29 press-fit condylar prostheses. The mean bone mineral content of the proximal tibia, measured the day before surgery using dual-photon absorptiometry was 5.48 g/cm for the porous-coated anatomic prostheses which were revised for aseptic loosening (n = 9). This was significantly higher (p = 0.02) than the mean of 4.33 g/cm for those which were not revised. Values for the two revised press-fit condylar knees (4.78 and 4.93 g/cm) were above the mean value (4.23 g/cm) for those which were not revised. We found no statistically significant (p = 0.38) difference between the bone mineral content of the 12 revised and nine unrevised unicompartmental arthroplasties. Low trabecular bone quality, measured as the pre-operative bone mineral content of the proximal tibia, was not a predictor for later revision surgery following uncemented total knee or unicompartmental knee arthroplasty.

Intrapelvic mass in a young woman with an uncemented hip arthroplasty.

Based on a case report in which wear of the polyethylene liner in an uncemented hip prosthesis led to the development of an intrapelvic mass, the pathogenesis, diagnosis and treatment are described. Characteristic osseous and soft tissue reactions caused by release of polyethylene particles to periarticular tissue are discussed as well as the differential diagnosis with infectious and malignant conditions. In the case treated, the differential diagnosis was also made with respect to gynecological pathology.

Long-term results after cemented revision of the femoral component in total hip arthroplasty.

The need for revision total hip arthroplasty has been increasing. The early results have been poor, and different revision techniques have been introduced. We report our results of 84 consecutive cemented first-time revisions of femoral components performed from 1981 through 1988 using a long-stem revision component. The average time to follow-up was 11.4 years (range, 7.9-15.0 years). Patients with 47 revisions had died; 2 of these had been rerevised. Two additional patients were lost to follow-up for other reasons. Of the living patients, 12 had been rerevised, leaving 23 patients (23 hips) for complete follow-up evaluation, including clinical and radiographic assessment. Of 23 patients, 15 reported no pain, 4 had only slight pain, and 4 had more severe pain. In 4 cases, there were definite radiographic signs of loosening of the femoral component. Kaplan-Meier survivorship analysis showed an overall 10-year survival of the femoral component of 77.9%. Using rerevision because of aseptic loosening or definite radiographic loosening as endpoint, the 10-year survival was 80.7%. Simple recementation is well indicated in elderly patients with only minor bone loss.

[Osteoid osteoma of the cervical spine]. / Osteoidt osteom i columna cervicalis.

Osteoid osteoma of the cervical spine is a rare benign tumour. A case of a 26 year-old female with osteoid osteoma in C2 is presented. She had a six year history of pain in the neck region. She suffered from limited neck movement, accentuation of pain during the night, but distinctive salicylate pain relief. Scintigraphic bone scan and CT scan, rather than MRI-scan are the most useful for localisation of the tumour in the spine and are essential for optimal planning before surgery is performed.

[Unsatisfactory results after repeated revision of hip alloplasties]. / Utilfredsstillende resultater efter gentagen revision af hoftealloplastik.

Sixty one cemented second revision total hip arthroplasties and 18 cemented third revision total hip arthroplasties were studied with emphasis on cause of failure, complications, risk of further revision, and clinical and radiographic outcome of surviving, not further revised patients. Aseptic loosening was the major reason for both second and third revisions followed by recurrent dislocations. Twenty one second revisions failed again. Postoperative dislocation was the major complication, entered in 10/61 second revisions and in 4/18 third revisions. Ten second revisions were reoperated on without exchange of components, but for reasons related to the implant. Clinical and radiographic outcome was favorable, but must be seen in the light of the high rate of further revisions. In 33/53 second revisions and in 5/13 third revisions left for evaluation, the overall outcome was considered unsatisfactory. Reoperations for failed arthroplasties should be the prerogative of highly experienced centers.

Internal fixation of femoral neck fractures. Dynamic Hip and Gouffon screws compared in 73 patients.

A prospective, randomized study comparing the Dynamic Hip screws and the Gouffon screws in the treatment of femoral neck fractures was terminated before the planned number of patients had been admitted, owing to a preponderance of early failure of the Gouffon screws (P 0.014); thus only 73 patients entered the study. After three years' follow-up, 25/38 Gouffon screws and 12/35 Dynamic Hip screws had failed. Six patients treated with Gouffon screws and 14 treated with Dynamic Hip screws had died. The outcome still favoured the use of Dynamic Hip screws (P 0.02).

Unsatisfactory results after repeated revision of hip arthroplasty. 61 cases followed for 5 (1-10) years.

61 cemented second revision total hip arthroplasties and 18 cemented third revision total hip arthroplasties were studied with emphasis on causes of failure, complications, risk of further revision, and clinical and radiographic results of surviving, not further revised patients. Aseptic loosening was the major reason for both second and third revisions followed by recurrent dislocations. Of 61 second revisions, 21 failed again. Postoperative dislocation was the major complication, encountered in 10/61 after second revisions and in 4/18 third revisions. 10 second revisions were reoperated on without exchange of components, but for causes related to the implant. The clinical and radiographic outcome of surviving, not further revised patients was favorable, but must be seen in the light of the high rate of further revisions. In 33 of 53 second revisions and in 5 of 13 third revisions left for evaluation, the outcome was considered unsatisfactory. We conclude that reoperations for failed arthroplasties should be the prerogative of highly experienced centers.

Clinical results after revision and primary total hip arthroplasty.

Results after 184 primary and 227 revision total hip arthroplasties were compared with an emphasis on rates of failure leading to reoperation and intra- and postoperative complications and on the clinical outcome of the nonrevised arthroplasties in the two series. The failure rate was 7% (11 of 156) in the primary series, versus 27% (54 of 195) in the revision series. The rate of complications was substantially higher after revision, due to 16% (36 of 227) intraoperative fractures of the femoral shaft and 6% (14 of 227) postoperative dislocations. Clinical assessment of the nonrevised arthroplasties in the two series revealed no difference with regard to relief of pain. For patients with concomitant disabling conditions functional outcome was inferior after revision, but for patients without such conditions the functional results of the two series were equal. The favorable clinical results of the nonrevised arthroplasties in the revision series must be seen in relation to the very high rate of failure leading to reoperation.

Survivorship analysis of failure pattern after revision total hip arthroplasty.

Failure, defined as established indication for or performed re-revision of one or both components, was analyzed using survivorship methods in 306 revision total hip arthroplasties. The longevity of revision total hip arthroplasties was inferior to that of previously reported primary total hip arthroplasties. The overall survival curve was two-phased, with a late failure period associated with aseptic loosening of one or both components and an early failure period associated with causes of failure other than loosening. Separate survival curves for aseptic loosening of femoral and acetabular components showed late and almost simultaneous decline, but with a tendency toward a higher rate of failure for the femoral component. No differences in survival could be found between the Stanmore, Lubinus standard, and Lubinus long-stemmed femoral components. A short interval between the index operation and the revision and intraoperative and postoperative complications were risk factors for early failure. Young age was a risk factor for aseptic loosening of the femoral component. Intraoperative fracture of the femoral shaft was not a risk factor for secondary loosening. No difference in survival was found between primary cemented total arthroplasty and primary noncemented hemiarthroplasty.

The HPC-device: a method to quantify the heel pad shock absorbency.

Previous studies have indicated that the shock absorbency of the heel pad is significant in the pathophysiology of pain conditions connected with heel strike. The purpose of this study was to develop a simple clinically usable method for quantification of the heel pad shock absorbency. The results of our efforts was the HPC-device which consists of a fixing device and a transducer. The HPC-device was found suitable in the evaluation of the heel pad force/deformation characteristics. The reproducibility of heel pad deformation was 0.96. Tests of six cadaver heel pads revealed a high correlation between the HPC result and the shock absorbency found by drop tests. In a normal material (200 heel pads), it was found that the shock absorption decreased with age and that men had significantly higher shock absorbency than women. Men also had significantly thicker heel pads than women. However, there was no linear correlation between the thickness of the heel pad and the shock absorbency, although the thinnest heel pads had the lowest shock absorbency. The HPC-device was found clinically usable and will be used in further testing of the significance of heel pad shock absorption for the development of heel strike dependent over-use injuries.

Recurrent anterior dislocation of the shoulder. A comparison of the results after the Bankart and the Putti-Platt procedures.

A retrospective comparison of the results after the Bankart and the Putti-Platt procedures in the treatment of recurrent anterior dislocation of the shoulder showed no significant differences in the rate of redislocation or in the limitation of outward rotation. The dislocation recurrence rate after surgery was 13% for the Bankart procedure and 22% for the Putti-Platt procedure. Only 67% of the patients were satisfied with the operation. The poor results seem to be due to the fact that the operations were performed by 16 different surgeons who had varying approaches to the operations.

Multiple fractures in a young diabetic patient.

Multiple fractures in a patient with juvenile diabetes mellitus are reported. The fractures could be spontaneous due to osteopenia caused by reduced bone mass found in diabetic patients. Bone and joint changes had a severe progression due to diabetic neuropathy. The importance of clinical and radiological examination is emphasized.

Fracture of the femur after knee arthroplasty.

The supracondylar fracture of the femur is a serious complication after total knee arthroplasty. We report our experience in the management of 16 patients with this complication and suggest that the main line of treatment should be conservative. Open reduction and plate fixation is precarious. In displaced fractures, however, the Rush pin technique was useful.

The Neer classification of fractures of the proximal humerus. An assessment of interobserver variation.

The reliability of the Neer classification of proximal fractures of humerus was examined by determining the agreement between pairs of observers using weighted kappa statistics. Anteroposterior and lateral radiographs of 100 surgical neck fractures were grouped independently by four observers. A low degree of agreement was found, especially between the most inexperienced observer and the rest. Considering the therapeutic consequences of a correct classification, these fractures should be assessed by experienced orthopedic surgeons or radiologists.