Long-term outcome of surgically-treated habitual patellar dislocation in children with coexistent patella alta. Minimum follow-up of 11 years.

We retrospectively reviewed the operative treatment carried out between 1988 and 1994 of eight patients with habitual patellar dislocation. In four the condition was bilateral. All patients had recurrent dislocation with severe functional disability. The surgical technique involved distal advancement of the patella by complete mobilisation of the patellar tendon, lateral release and advancement of vastus medialis obliquus. The long-term results were assessed radiologically, clinically and functionally using the Lysholm knee score, by an independent observer. The mean age at operation was 10.3 years (7 to 14) with a mean follow-up of 13.5 years (11 to 16). One patient required revision. At the latest follow-up, all patellae were stable and knees functional with a mean Lysholm knee score of 98 points (95 to 100). In those aged younger than ten years at operation there was a statistically significant improvement in the sulcus angle at the latest follow-up (Student's t-test, p = 0.001). Two patients developed asymptomatic patella infera as a late complication. This technique offers a satisfactory treatment for the immature patient presenting with habitual patellar dislocation associated with patella alta. If performed early, we believe that remodelling of the shallow trochlea may occur, adding intrinsic patellofemoral stability.

Prevention of venous thromboembolism after knee arthroplasty. A randomized, double-blind trial comparing enoxaparin with warfarin.

OBJECTIVE: To compare the effectiveness and safety of fixed-dose enoxaparin and adjusted dose warfarin in preventing venous thromboembolism after knee arthroplasty. DESIGN: A randomized, double-blind controlled trial. SETTING: 8 university hospitals. PATIENTS: 670 consecutive patients who had knee arthroplasty. INTERVENTION: Patients were randomly assigned to receive enoxaparin (30 mg subcutaneously every 12 hours) or adjusted-dose warfarin (international normalized ratio, 2.0 to 3.0). Both regimens were started after surgery. MEASUREMENTS: The primary end point was the incidence of deep venous thrombosis in patients with adequate bilateral venograms; the secondary end point was hemorrhage. RESULTS: Among the 417 patients with adequate venograms, 109 of 211 warfarin recipients (51.7%) had deep venous thrombosis compared with 76 of 206 enoxaparin recipients (36.9%) (P = 0.003). The absolute risk difference was 14.8% in favor of enoxaparin (95% Cl, 5.3% to 24.1%) Twenty-two warfarin recipients (10.4%) and 24 enoxaparin recipients (11.7%) had proximal venous thrombosis (P>0.2). The absolute risk difference was 1.2% in favor of warfarin (Cl, -7.2% to 4.8%). The incidence of major bleeding was 1.8% (6 of 334 patients) in the warfarin group and 2.1% (7 of 336 patients) in the enoxaparin group (P>0.2). The absolute risk difference was 0.3% in favor of warfarin (Cl, -2.4% to 1.8%). CONCLUSIONS: A postoperative, fixed-dose enoxaparin regimen is more effective than adjusted-dose warfarin in preventing deep venous thrombosis after knee arthroplasty. No differences were seen in the incidence of proximal venous thrombosis or clinically overt hemorrhage.

[Efficacy and safety of prophylactic preoperative administration of low-dose warfarin in cemented total knee prostheses]. / Efficacité et sécurité de la prophylaxie avec warfarine faible dose débutée en pré-opératoire lors de prothèses totales de genou cimentées.

One hundred and fifty six consecutive cemented total knee arthroplasties (TKA) in 147 patients (39 males, 108 females, mean age: 67) received preoperatively low-dose-warfarin for thromboembolic prophylaxis. Warfarin 10 mg was given the night before surgery and warfarin 5 mg the night of surgery. Thereafter, the dosage was adjusted to maintain a prothrombin time between 1.2-1.5 times control (INR = 2.0-3.0). The screening for any deep vein thrombosis (DVT) in the operated limb was by ascending venography. The reported incidence of DVT after TKA without prophylaxis is superior to 50%, more than 10% of those are proximal DVT. In this study, the overall incidence of DVT is down to 22.4%. Only five patients (3.4%) had a proximal DVT. There were no deaths and no clinical pulmonary embolisms. Patients with venous insufficiency had a significantly higher incidence of DVT (36.7%, p = 0.05). The average blood loss was 406 ml. Three major local bleedings occurred (2.0%). At one year follow-up, there were no infections. Low dose warfarin is efficacious in reducing DVT formation with TKA. It is safe and does not create excessive bleeding in cemented TKA.

Bone and soft tissue changes with oral phosphate supplements.

Oral phosphate supplements in divided doses were given to adult dogs for a period of 10 months. Bone density, bone turnover, serum chemistry values, and the calcium content of soft tissues were determined initially and at the end of the experimental period. Serum calcium remained the same; serum phosphate decreased slightly but significantly. The decrease in phosphate was related to an increase, compared with pre-experimental values, in bone resorption which was seen in the terminal ulna and iliac crest bone samples from all dogs. Serum immunoreactive parathyroid hormone was increased (compared with pre-experimental values) after 5 and 10 months of phosphate supplementation; this increase was related to the bone loss and the decrease in serum phosphate. Soft-tissue calcification could be demonstrated histologically in the kidney and in the lens of the eye where it resulted in cataracts. Calcium content increased in the thoracic aorta, kidney, heart, and tendon but not in skeletal muscle. Phosphate supplements in adult dogs appear to produce secondary hyperparathyroidism, bone loss, and calcification of soft tissues.