Marcelo P. Camargo

High Tibial Osteotomy with a Calibrated Osteotomy Guide, Rigid Internal Fixation, and Early Motion. Long-Term Follow-up*

Background: We studied the results of sixty-four valgus-producing high tibial osteotomies performed with the use of a calibrated osteotomy cutting guide and rigid internal fixation, and followed by early motion, in fifty-six patients who had medial unicompartmental osteoarthritis and varus malalignment. Long-term studies have demonstrated that a high tibial osteotomy performed with staple fixation and followed by immobilization in a cast has an expected survival rate of approximately 85 percent at five years and 60 percent at ten years (in studies of ninety-five knees and 213 knees, respectively). To the best of our knowledge, there are no long-term reports on high tibial osteotomies performed with a calibrated osteotomy cutting guide and rigid internal fixation and followed by early motion. Methods: The indications for high tibial osteotomy were medial unicompartmental osteoarthritis and varus malalignment. A lateral closing-wedge osteotomy was performed. The patients were reexamined to obtain a knee score, to make lateral radiographs of both knees, and to make a full-length anteroposterior radiograph (showing the entire lower extremity, including the hip and ankle) of the involved knee with the patient standing. Results: Twenty-one knees were treated with a subsequent total knee arthroplasty at an average of sixty-five months after the high tibial osteotomy. The remaining forty-three knees had a good or excellent clinical result, with an average knee score of 94 points at an average of 8.5 years after the osteotomy. Survivorship analysis showed an expected rate of survival, with conversion to a total knee arthroplasty as the end point, of 85 percent at five years and 53 percent at ten years. No patient had patella baja postoperatively. There were six complications: four superficial wound infections, one superficial-vein thrombosis, and one delayed union (union occurred at five months). Conclusions: High tibial osteotomy has been criticized because of a high rate of complications, a loss of effectiveness with time, and the difficulty of conversion to a total knee arthroplasty secondary to patella baja. In our series, in which an osteotomy was performed with a calibrated osteotomy cutting guide and rigid internal fixation and was followed by early motion, the rate of complications was low and approximately two-thirds of the knees had a good or excellent clinical result at an average of 8.5 years. Conversion to a total knee arthroplasty was accomplished without difficulty in the patients who had this procedure. We highly recommend high tibial osteotomy with a calibrated osteotomy cutting guide, rigid internal fixation, and early motion for patients who wish to continue an active lifestyle.

Treatment of infected total knee arthroplasty using an articulating spacer.

Twenty-six patients with late infected total knee arthroplasties were treated by debridement and removal of components and all cement, preserving collateral ligaments. At time of debridement, an articulating spacer was fashioned to allow partial weightbearing and knee range of motion (ROM) during rehabilitation. This spacer was implanted using antibiotic-impregnated bone cement. For this purpose, 4.8 g of powdered tobramycin was mixed with each 40-g batch of Simplex cement. Cement was applied early to the components, but applied late to the femur, tibia, and patella to allow molding to the defects and bone without adherence to bone. Patients received tailored intravenous antibiotic therapy for 6 weeks in addition to this antibiotic-impregnated cement for treatment of a variety of gram positive and gram negative organisms. All patients had cemented revision total knee arthroplasty using antibiotic-impregnated cement with standard cementing techniques used. All patients but 1 had reimplantation; this patient died of unrelated causes before revision. Range of motion before revision was 10° to 95°. Followup averaged 30 months (range, 13–70 months). The average Modified Hospital for Special Surgery Knee Score after revision was 87 points (range, 53–100 points), with 92% good to excellent results. Range of motion after reimplantation was 5° to 106°. There have been no recurrences of infection. Use of an articulating spacer to treat infected total knee arthroplasty improves ultimate ROM and soft tissue health and significantly decreases the risk of reinfection.

Cementless total knee arthroplasty in patients 50 years or younger.

Total knee arthroplasty now is being advocated for use in younger patients with posttraumatic and rheumatoid arthritis. Advances in technology, design, and materials potentially have allowed for more predictable results. There has been continued interest in cementless fixation for use in younger patients. Between 1986 and 1998, 75 total knee replacements in 57 patients 50 years or younger were done. All surgeries were done by one surgeon (AAH). There were 35 left knees and 40 right knees. The average age of the patients was 42 years (range, 31–50 years). Followup averaged 111 months. Preoperative range of motion was 5° to 106° and postoperative range of motion was 2° to 113°. Modified Hospital for Special Surgery knee scores improved from an average of 67 points preoperatively to an average of 97 points postoperatively. The majority of the diagnoses were posttraumatic arthritis or osteoarthritis (57%), indicating a young, active group of patients. There were two infections and 12 polyethylene exchanges. There were no revisions for loosening or implant failure. There was a correlation between prior knee surgeries and the need for a manipulation. Radiographically, there were no loose implants. Cementless fixation in the young patient with high physical demands was clinically reliable.

Patellar Component Medialization in Total Knee Arthroplasty

Intraoperative correction of patellar maltracking has traditionally involved the use of a lateral retinacular release. Problems, however, related to lateral retinacular release include increased postoperative pain and wound healing complications, compromised patellar blood flow, and longer rehabilitation. The purpose of this study was to assess the effect of patellar medialization in total knee arthroplasty. One hundred forty patients underwent total knee arthroplasty using the same components. Two groups of 70 patients each made up the study. Group 1 included patients whose patellar components were centralized on the patella, and group 2 consisted of patients in whom the patellar component was medialized to reproduce the patients anatomic high point (ie, sagittal ridge). Lateral retinacular release was required in 45.5% of the patients in group 1 compared with 17% in group 2. The technique of patellar medialization is described.

6- to 10-year experience using countersunk metal-backed patellas

Three hundred two consecutive cementless total knee arthroplasties (Natural Knee, Intermedics Orthopedics, Inc., Austin, TX) were performed using a metal-backed, porous-coated patellar component. Fifty-nine patients died and 31 were lost to follow-up evaluation, resulting in 212 knees available for evaluation at 6 to 10 years. The mean follow-up period was 91 months. The mean modified Hospital for Special Surgery total knee score improved from 58 before surgery to 98 at the most recent follow-up visit. Mean patellar translation and tilt were 2.75 mm and 3.5 degrees, respectively. There were no patellar lucencies nor loosening. Eleven patients (5%) underwent revision of the patellar component. Overall patellar survivorship was 96%. Comparatively good results can be achieved with the use of a metal-backed patellar component if component design, surgical technique, and patellar alignment are properly addressed.