Russell E. Windsor

Technical considerations of total knee arthroplasty after proximal tibial osteotomy.

Forty-five total knee replacements in forty-one patients who had continued to have progressive osteoarthritis after a proximal tibial osteotomy were evaluated prospectively. There were 51 per cent excellent, 29 per cent good, 4 per cent fair, and 16 per cent poor results after a minimum follow-up of two years. The resection of tibial bone that was produced by the osteotomy could not be related causally to the fair or poor clinical results that were found after arthroplasty. Radiographic study, however, showed that 80 per cent of the knees had patella infera before the arthroplasty, which may contribute to altered biomechanics of the patellofemoral joint of the arthroplasty. The procedure for total knee replacement is made more difficult by the previous osteotomy, and a custom-made prosthesis may be required. The clinical results that were obtained in this series are similar to those for the revision total knee arthroplasties that have been done at this institution, but they were not as satisfactory as those that were obtained after primary total knee replacement. Our results should be considered when a surgeon compares the advantages and disadvantages of proximal tibial osteotomy with those of total knee arthroplasty for an older patient who has unicompartmental osteoarthritis of the knee.

Two-stage reimplantation for the salvage of total knee arthroplasty complicated by infection. Further follow-up and refinement of indications.

Thirty-eight total knee replacements (in thirty-five patients) that were complicated by infection were treated with a two-stage protocol for reimplantation. The clinical results in these knees (nine of which have been previously reported on) were evaluated at an average follow-up of four years (range, 2.5 to ten years). There was only one documented recurrence of infection with the original organism. Three patients in whom the immunological system was suppressed had a subsequent hematogenous infection with a different organism. According to the knee-rating system of The Hospital for Special Surgery, there were eleven excellent, thirteen good, six fair, and seven poor results. For one patient who had severe polyarticular rheumatoid arthritis, the result could not be rated. The results of this study suggested that the two-stage protocol for reimplantation, with a six-week interval of intravenous antibiotic therapy, is the procedure of choice for the treatment of an infection around a total knee arthroplasty. A patient who has polyarticular rheumatoid arthritis and in whom the immunological system is suppressed may not be an ideal candidate for the protocol. Gram-negative bacterial infection may be treated with this protocol, provided the organism is sensitive to relatively non-toxic antibiotic medication.

Revision total knee arthroplasty with use of modular components with stems inserted without cement.

We reviewed the results of seventy-six revision total knee replacements, performed between 1980 and 1988 on the Knee Service at The Hospital for Special Surgery, in seventy-four patients. Sixty-five patients (sixty-seven knees; 88 percent) had a complete clinical examination and radiographic evaluation, and nine patients (nine knees; 12 percent) were only interviewed by telephone. Survivorship analysis was performed for all patients. The average duration of follow-up was three years and six months (range, two to nine years). Only patients who had had revision of the femoral component or the tibial component, or both, because of aseptic failure were included. The tibial component of all prostheses that were used for revision had a metal backing. Cement was placed on the cut surfaces in the metaphyseal region of the femur and tibia. Fluted diaphyseal intramedullary rods were used in all patients and were not cemented. Metal wedges and augments were used to fill osseous defects when necessary. The average preoperative knee score, according to the rating scale of The Hospital for Special Surgery, was 49 points (range, 0 to 62 points). Postoperatively, the knee score improved to an average of 76 points (range, 0 to 97 points). Of the sixty-seven knees that had complete follow-up, fifty-six (84 percent) had an excellent or good result and five (7 percent) had a fair or poor result. In six (8 percent) of the seventy-six knees, the prosthesis failed, necessitating another revision. Failure was defined as removal or a recommendation for removal of the implant.(ABSTRACT TRUNCATED AT 250 WORDS)

Observations on patellar height after proximal tibial osteotomy.

Sixty-six knees (sixty patients) that had had a proximal tibial osteotomy were evaluated to determine if any alteration of the patellar height had occurred as a result of the operation. Eighty-nine per cent of the patellae, as measured by the Insall-Salvati index, and 76.3 per cent, as measured by the Blackburne-Peel index, were observed to be lowered as they appeared on the postoperative lateral radiograph. This was probably due to shortening of the patellar ligament after prolonged immobilization in a cast, interstitial scarring of the patellar ligament, and new-bone formation in the area of insertion of the patellar ligament. There was no correlation between the postoperative height of the patella and the need for subsequent revision to a total knee replacement.

Patellar fractures in total knee arthroplasty

The incidence of patellar fractures following total knee arthroplasty varies from 3% to 21%. This problem has been attributed to avascular necrosis of the patella secondary to the surgical approach, including medial arthrotomy and lateral release, patellar bone resection, thermal necrosis, and anatomic variation. Management of these patellar fractures may be conservative or surgical.

Pneumatic sequential-compression boots compared with aspirin prophylaxis of deep-vein thrombosis after total knee arthroplasty.

This prospective, randomized study was undertaken to compare the effectiveness of pneumatic sequential-compression boots with that of aspirin in preventing deep-vein thrombosis after total knee arthroplasty. Patients were randomly assigned to one of two prophylactic regimens: compression boots or aspirin. One hundred and nineteen patients completed the study. Seventy-two patients had unilateral arthroplasty and forty-seven, one-stage bilateral arthroplasty. In the unilateral group, the incidence of deep-vein thrombosis was 22 per cent for the patients who used compression boots compared with 47 per cent for those who received aspirin (p less than 0.03). In the bilateral group, the incidence of deep-vein thrombosis was 48 per cent for the patients who used compression boots compared with 68 per cent for those who received aspirin (p less than 0.20). The results confirm the effectiveness of compression boots in the treatment of patients who have had unilateral total knee arthroplasty. Despite the use of compression boots, however, patients who had bilateral arthroplasty were at greater risk for the development of deep-vein thrombosis.

Long-term results after total condylar knee arthroplasty. Significance of radiolucent lines.

In a prospective study of 123 total condylar knee arthroplasties, radiolucent lines were noted at the bone-cement interface about the tibial component in 65% of the knees. In 36%, the line was thin (less than 2 mm) and under either the medial or lateral tibial plateau. In 22%, thin lines were seen under both the medial and lateral plateaus. There was no statistically significant correlation between the occurrence of thin radiolucent lines in any location and the eventual postoperative clinical result. In 7%, thick lines (greater than 2 mm) were noted about the central peg of the prosthesis as well as under both plateaus and were associated with poor results. A 1-mm radiolucent interface was attached to various tibial components, which were then cemented into cadaver knees. For the polyethylene total condylar component, flexion or rotation of the prosthesis more than 5 degrees, angulation of the roentgen beam more than 6 degrees, or offsetting the beam more than 2.5 cm prevented visualization of the radiolucent line. With metal-backed components, more than 4 degrees of flexion obscured the lines. Therefore, extremely careful positioning of postoperative radiographs is essential for evaluating radiolucent lines after total knee arthroplasty.

Randomized trial of epidural versus general anesthesia: outcomes after primary total knee replacement.

To compare the effects of epidural anesthesia and general anesthesia on early postoperative outcomes after unilateral primary total knee replacement, 262 patients were randomly assigned to receive either epidural or general anesthesia. All patients received a common rehabilitation protocol including a standardized assessment of progress. One hundred eighty-eight patients received a common thromboembolic prophylaxis protocol with postoperative aspirin, and had a standardized surveillance protocol to detect thromboembolic complications. Deep vein thrombosis was determined by venography on the operative limb, and pulmonary embolism was determined by comparison of preoperative and postoperative lung perfusion scans. The epidural anesthesia group reached all rehabilitative milestones earlier postoperatively than did the general anesthesia group, with a statistically significant earlier attainment of stair climbing. The incidence of deep vein thrombosis was 40% with epidural anesthesia, and 48% with general anesthesia. There were no clots proximal to the popliteal veins. The incidence of pulmonary embolism on lung scan was 12% with epidural anesthesia and 9% with general anesthesia. Epidural anesthesia is associated with more rapid achievement of postoperative in hospital rehabilitation goals after total knee replacement. A minor reduction in postoperative deep vein thrombosis rate was observed with epidural anesthesia, but this did not reach statistical significance. No difference in early postoperative pulmonary embolism was observed between the 2 types of anesthesia.

Arthroplasty for the stiff or ankylosed knee

Twenty stiff (range of motion, less than 50 degrees) and six ankylosed knees were replaced with the posterior stabilized condylar prosthesis and evaluated after an average of 4.5 years (range, 2.5-7.5 years). There were 81% good to excellent, 11.5% fair, and 7.5% poor results. The maximum overall degree of flexion improved from an average of 60 degrees before surgery to 85 degrees after surgery. Flexion contracture was reduced from 28 degrees to 7 degrees, and the total arc of motion significantly increased from 32 degrees to 78 degrees. Less motion was achieved in the ankylosed knees. A modified inverted V-Y quadricepsplasty was a useful approach to the knee in 11 cases.

High tibial osteotomy.

Abstract High tibial osteotomy is effective for managing a variety of knee conditions, including gonarthrosis with varus or valgus malalignment, osteochondritis dissecans, osteonecrosis, posterolateral instability, and chondral resurfacing. The fundamental goals of the procedure are to unload diseased articular surfaces and to correct angular deformity at the tibiofemoral articulation. Although the clinical success of total knee arthroplasty has resulted in fewer high tibial osteotomies being done during the past decade, the procedure remains useful in appropriately selected patients with unicompartmental knee disease. Renewed interest in high tibial osteotomy has occurred for a number of reasons. These include the prevalence of physiologically young active patients presenting with medial compartment osteoarthritis; the advent of new techniques for performing the procedure (ie, improved instrumentation and fixation plates for medial opening wedge osteotomy, dynamic external fixation for medial opening wedge osteotomy, and improved instrumentation for lateral closing wedge osteotomy); and the need to concomitantly correct malalignment when performing chondral resurfacing procedures (ie, autologous chondrocyte transplantation, mosaicplasty, and microfracture).