A 52-year-old man with limited hip movement.

This case is presented to illustrate the imaging and clinical findings of a condition of interest to orthopedic surgeons. The initial findings are noted on this page. The clinical and imaging diagnoses are presented on the following pages.

Influence of patellar thickness on results of total knee arthroplasty: does a residual bony patellar thickness of

With patellar thickness averaging 24.0 mm and 21.9 mm in Singapore men and women undergoing total knee arthroplasty, achievement of precut thickness is difficult if the recommended residual bony thickness of 15 mm is maintained. We retrospectively compared the clinical outcome of 56 patellae resurfaced 12 mm (mean residual thickness, 13.7 mm). Both groups were comparable in terms of demographic characteristics, presentation, precut patellar thickness, and operative details (P> .05). Knee scores (P= .627), extensor mechanism function (P= .625), and postoperative range of motion (P= .344) were comparable. Differences in the overall (P= .167) and patellar (P= .061) complication rates as determined by chi-square test on the SPSS 10.0 program were not significant, although there were 4 patella-related complications in group 2. Increased patella-related complications may be associated with an excessive patellar composite of the patellofemoral articulation. A residual patellar thickness of <12 mm did not appear to affect the clinical outcome in this series.

Deep vein thrombosis after total knee replacement.

INTRODUCTION: The prevalence of deep vein thrombosis after total knee replacement has been quoted to be between 46% and 84% in the Western literature. The aims of this study were to determine its prevalence in the Singapore population and to assess the need for prophylaxis against deep vein thrombosis. MATERIALS AND METHODS: We examined data on 100 consecutive patients undergoing total knee replacement at the Adult Reconstructive Service, Department of Orthopaedic Surgery, Singapore General Hospital and assessed the possible risk factors: age, sex, weight, previous surgery, unilateral or bilateral surgery, postoperative rehabilitation, tourniquet and operating time. Functional and knee scores based on the Knee Society Clinical Rating System were also assessed. No prophylaxis was given to these patients. These patients underwent a duplex scan of both lower limbs on the seventh postoperative day. Treatment was instituted only if proximal deep vein thrombosis was detected. RESULTS: The overall incidence of deep vein thrombosis was 14% with 64.3% of it occurring distally. Deep vein thrombosis was more common in bilateral total knee replacement (22.2%) compared to unilateral total knee replacement (13.2%). Partial thrombosis was present in 71.4% and occurred predominantly in the ipsilateral leg. There was no evidence of propagation. Only 1 patient developed pulmonary embolism and was treated successfully but there was no evidence of deep vein thrombosis on duplex scan in this patient. CONCLUSION: There was no significant difference in the risk factors between patients who did and those who did not develop deep vein thrombosis.

Use of low molecular weight heparin for prevention of deep vein thrombosis in total knee arthroplasty--a study of its efficacy in an Asian population.

INTRODUCTION: The aims of this paper were to study the incidence of deep vein thrombosis following total knee replacement in an Asian population and to evaluate the role of low molecular weight heparin for deep vein thrombosis in this setting. MATERIALS AND METHODS: We prospectively studied two groups of 100 consecutive patients undergoing total knee replacement separately. Group 1 did not receive any low molecular weight heparin and group 2 received low molecular weight heparin, nodraparin calcium (Fraxiparine) according to body weight. The sex distribution, age group, weight, preoperative knee and function scores, and postoperative rehabilitation were similar for both groups. A single ultrasound technician performed ultrasound duplex scan of both lower limbs on the seventh postoperative day. RESULTS: The incidence of deep vein thrombosis in group 1 was 14% (14 patients, 5 proximal vein thromboses and 9 distal vein thromboses) while in group 2, no patients developed deep vein thrombosis. There was no increased incidence, either local or systemic, of major bleeding complications with the use of low molecular weight heparin. CONCLUSION: While the incidence of deep vein thrombosis following total knee replacement in an Asian population appears lower compared to Western populations, the use of low molecular weight heparin for thromboprophylaxis appears to further reduce the incidence without major bleeding complications.

Results of revision total knee arthroplasty.

BACKGROUND/AIM OF STUDY: The results of primary total knee arthroplasties have improved over the years but some still fail, requiring revision. Revision total knee arthroplasty is technically more difficult and has not enjoyed the same success rates as the index operation. The aim of this retrospective study was to review the results of revision total knee arthroplasties carried out at our centre. This is the first study in Singapore on revision total knee arthroplasty. METHODS: A retrospective study where 17 patients (18 knees) had been followed up since their revision operations were clinically assessed. Based on the Knee Society Clinical Scoring System, they were assigned separate knee and function scores (each having a maximum possible 100). RESULTS: The mean knee score was 76 (range 35-93), which rates as good. Of the 18 knees, 67% had excellent or good knee scores. By comparison, the mean function score was 56 (range 0-90) which rates as poor and 33% had excellent or good function scores. CONCLUSION: Revision total knee arthroplasty achieves good and excellent results in spite of technical difficulties often associated with the revision operation. The difference in mean knee and function scores emphasises that many other factors such as physical strength and stamina affect function. Nevertheless, 15 patients were able to walk out of their house and around their neighbourhood for varying distances. This satisfied their expectations and the poor mean function score may reflect different expectations of patients overseas from whence this scoring system originated.

The Mitchell distal metatarsal osteotomy for hallux valgus--the Singapore General Hospital experience.

BACKGROUND: Fifty-five Mitchell distal metatarsal osteotomies for hallux valgus performed over a period of four years have been retrospectively reviewed. The 38 patients were followed for an average of 30 months (range 12 to 60 months). RESULTS: The preoperative hallux valgus angle averaged 30.9 degrees +/- 8.2 degrees SD (range 18 degrees to 60 degrees) and the postoperative angle averaged 12.2 degrees +/- 4.6 degrees (range 5 degrees to 20 degrees). CONCLUSION: Ninety-two percent of the patients were satisfied with the result of the procedure. They stated that, given the identical situation, they would undergo the operation again.

Chevron osteotomy for hallux valgus--SGH experience.

Thirty-one chevron osteotomies for hallux valgus performed over a period of four years were reviewed. Their follow-up period ranged from one to five years. All the patients had pain over the bunion prior to operation. After operation, there was marked decrease of pain over the first matatarsophalangeal joint. The preoperative hallux valgus angle average 27 degrees and the postoperative angle averaged 12 degrees. The preoperative intermetatarsal angle averaged 13 degrees and the postoperative angle, 8 degrees. Ninety-one per cent of the patients were satisfied with the result of the procedure.

The results of open acromioplasty in impingement syndrome--a retrospective study.

Many published reports have reported generally good results of open acromioplasty in shoulder impingement syndrome. This paper studied retrospectively the results of open acromioplasty done in the Singapore General Hospital. A total of 23 open acromioplasties performed on 22 patients with shoulder impingement syndrome were studied. The post-operative results of the acromioplasties were evaluated using the University of California, Los Angeles (UCLA) shoulder scoring system. With the UCLA shoulder scoring system, results were excellent or good in 14 (60.8%), fair in 7 (30.5%) and poor in 2 (8.7%). At the same time the male sex was identified to have statistically significant better results as compared to the females. There was a trend towards poorer results in those at or above 50 years of age, duration of symptoms of less than 2 years and those with acromiohumeral distance of less than or equal to 1.0 cm. The presence of rotator cuff tears and the duration of follow-up were found not to have any bearing on the post-operative outcome. This procedure seems to be reasonably effective and safe. Careful patient selection and early post-operative rehabilitation with physiotherapy is of utmost importance.

Comparing staple fixation to buttress plate fixation in high tibial osteotomy.

A retrospective study was made between July 1988 and March 1992, of 171 patients (223 knees) who had high tibial osteotomy at the Singapore General Hospital. Seventy-four cases (97 knees) had buttress plate fixation and 97 cases (126 knees) had staple fixation. The mean postoperative Hospital for Special Surgery Knee Score was 87.0 for the buttress plate group and 87.4 for the staple group. The difference was statistically not significant (P > 0.05). The hospitalisation stay was shorter in the staple fixation group as compared to the buttress plate group (P < 0.05). However, the mean rehabilitation time was shorter in the buttress plate group as compared to the staple fixation group (P < 0.05). The incidence of wound infection was higher among those fixed with buttress plate (9 cases) as compared to those fixed with staple (1 case). The difference was statistically significant (P < 0.05). Buttress plate fixation did not seem to eliminate the risk of non-union of the osteotomy (4 out of 126 osteotomies compared to 3 out of 97 in the staple group), neither did it prevent recurrence of varus deformity (2 out of 126 osteotomies). Overall it would appear that buttress plating did not have any significant advantage over staple fixation for high tibial osteotomy.

Comparison of the results of spinal fusion for spondylolisthesis in patients who are instrumented with patients who are not.

Eighty-five patients who had surgery for spondylolisthesis were studied retrospectively both clinically and radiologically to determine if instrumentation lead to better fusion rates and clinical outcome. Degenerative spondylolisthesis accounted for 57 cases and patients who had instrumentation did have a better fusion rate and clinical outcome, with 60% of patients having complete relief from pain. In the group with isthmic spondylolisthesis (28 patients), there was also an improved fusion rate with instrumentation. However, these patient took a longer time before returning to work and had to be protected in a polythene brace. The improved fusion rate radiologically with instrumentation did not translate to better clinical results with regard to pain relief and disability. One patient developed ascending epidural haematoma with instrumentation and resulted in paraplegia. She had incomplete recovery during the follow-up.

Chondrosarcoma of the spine--report of two cases.

Chondrosarcoma arising from the spine is a rare malignant tumour, associated with a poor outlook due to inadequate excision in the majority of the cases. We report two cases arising from the cervical and the thoracic spine. Both survived 15 and eight years respectively. This condition carries with it a grave prognosis because of its proximity to the vital structures, making complete extirpation of the tumour frequently difficult if not impossible. Recent developments and progress in adjuvant radiation therapy has improved the prognosis significantly.