Biomedical subjects

William M Mihalko

Publications and source records attributed to William M Mihalko.

5 recordsLinked to original sources

PubMed2003

Bone resection and ligament treatment for flexion contracture in knee arthroplasty.

A retrospective study of 103 knees (88 patients) who had primary total knee arthroplasty with a flexion contracture ranging from 20 degrees to 60 degrees was done to tabulate the primary soft tissue structures released during surgery and to identify any residual deformity. The average flexion contracture preoperatively was 27.1 degrees +/- 8 degrees and postoperatively was 2.7 degrees +/- 3.4 degrees (range, 0 degrees -10 degrees ). The average followup was 70.4 months (range, 12-180 months). Only medial or lateral soft tissue balancing procedures were necessary to correct the flexion contracture in 37 knees (35.9%) and no medial or lateral release was necessary in 25 knees (24.3%), of which 16 had a balanced posterior cruciate ligament. The posterior capsule was released on the deformity side of the knee in 15 knees (14.6%) and on the opposite side of the deformity in seven knees (6.8%). The posterior cruciate ligament was balanced in 21 knees (20.4%) and was released in four knees (3.9%). For all knees in which the posterior cruciate ligament was released or balanced, it was done for excessive rollback and tightness in flexion and not for flexion contracture management. In two patients (2%) an additional 4 mm of distal femur was resected for a 45 degrees and a 25 degrees flexion contracture. The data suggest that a contracted collateral ligament is the most likely primary structure whose effective release allows correction of the flexion contracture in most cases.

Arthroplasty, Replacement, Knee↗

PubMed2003

Osteonecrosis after powered core decompression.

A 44-year-old man with alcohol-related osteonecrosis of his left femoral head, Ficat Stage 2, was treated by femoral head decompression. During this procedure the (1/4)-inch trephine driven by a power reamer became lodged in the femoral head and became hot to the touch. The trephine eventually was removed with difficulty after the decompression was completed. Four and a half years later, the patient continued to have progressive pain and difficulty ambulating. A radiograph at the time revealed a wide zone of symmetric increased density about the core decompression track. A total hip arthroplasty was done, yielding the femoral head and neck for study. Histologic sections of the femoral head and neck showed that the entire length of the core decompression track in the specimen was surrounded by 2.7 cm of unrepaired necrotic bone. The evidence suggests that extensive additional necrosis was produced iatrogenically during the core decompression with the powered trephine. Necrosis secondary to either heat generation or increased pressure along the trephine track is presented as possible mechanisms for this unusual finding.

Adult↗

PubMed2002

Ranawat Award paper. Effect of selective lateral ligament release on stability in knee arthroplasty.

The current authors evaluated a fundamental approach to balancing the lateral ligaments of the knee that begins with aligning the implants correctly in flexion and extension, proceeds to assessing stability in flexion and extension, and concludes with releasing tight structures based on their function throughout the arc of flexion. Seventeen knees from cadavers were used to evaluate stability at various degrees of flexion after total knee arthroplasty, and then stability was reevaluated after release of selected ligaments. The iliotibial band and posterior capsule were effective lateral stabilizers only in full extension. The lateral collateral ligament had a major stabilizing effect throughout the arc from 0 degrees to 90 degrees flexion. The iliotibial band and popliteus tendon and posterolateral corner capsule had little effect when the other ligaments were intact. When tested in the absence of the other lateral ligaments, the popliteus tendon and posterolateral corner capsule had significant stabilizing effects throughout the flexion arc. The popliteus tendon exerted its effect mostly from 60 degrees to 90 degrees flexion. The posterolateral corner capsule was effective mostly at 0 degrees to 30 degrees flexion. The iliotibial band had a significant stabilizing effect from 0 degrees to 30 degrees flexion.

Arthroplasty, Replacement, Knee↗

PubMed2002

Surgical procedure for flexion contracture and recurvatum in total knee arthroplasty.

A specific protocol for dealing with flexion contracture and recurvatum in total knee arthroplasty surgery was evaluated. In cases of flexion contracture, this protocol included choosing the larger femoral size when the femur was between sizes to make the flexion space smaller and to allow overresection of the tibial surface to correct the flexion contracture. In all cases, bone resection was done first, osteophytes were resected next, and ligaments were balanced after the trials were in place. Extra bone was resected from the distal femur to correct residual flexion contracture only if ligament balancing failed to correct the deformity. In cases of recurvatum, the smaller femoral size was chosen to enlarge the flexion space, allowing underresection of the tibia to stabilize the knee in extension. The cutting guides were positioned so that 3 to 5 mm less than the distal thickness of the femoral component was removed to stabilize the knee in extension. To evaluate this protocol, a computerized database was used to review records of 530 patients (552 knees) who had flexion contracture (542 knees) or recurvatum (10 knees) before surgery. Ligament release and correction of varus or valgus contracture corrected flexion contracture to less than 3 degrees in 515 knees (95%). Sixteen knees (3%) had release of the posterior capsule to correct residual flexion contracture, and 11 knees (2%) required overresection of the distal femoral surface to achieve correction of flexion contracture. By 1 year the flexion contracture was 2 degrees +/- 1 degree. In the knees with preoperative recurvatum, none had residual recurvatum at the conclusion of surgery, and none had recurrent deformity. None of the knees required a hinge or a stabilized component with a highly conforming central post.

Aged↗

PubMedDate not supplied

Total knee arthroplasty in the valgus knee.

The valgus knee presents a unique set of problems that must be addressed during total knee arthroplasty. Both bone and soft-tissue deformities complicate restoration of proper alignment, positioning of components, and attainment of joint stability. The variables that may need to be addressed include lateral femoral condyle or tibial plateau deficiencies secondary to developmental abnormalities, and/or wear; primary or acquired contracture of the lateral capsular and ligamentous structures; and, occasionally, laxity of the medial collateral ligament. Understanding the specific pathologic anatomy associated with the valgus knee is a prerequisite to selecting the proper surgical method to optimize component position and restore soft-tissue balance.

Arthroplasty, Replacement, Knee↗