The correction of severe varus deformity in total knee arthroplasty by tibial component downsizing and resection of uncapped proximal medial bone.
ABSTRACT The clinical and radiologic outcome of 10 patients (12 knees) with a mean varus deformity of 24 degrees (range, 20 degrees to 40 degrees ) treated with total knee arthroplasty (TKA) is presented. We describe a technique of downsizing and lateralizing the tibial component with subsequent removal of the proximal medial tibia flush with the downsized component. At a mean follow-up of 42 months (range, 12 to 64 months), the mean preoperative Knee Society and function scores had improved from 24 and 34 to 94 and 85, respectively, at follow-up. No implant has been revised. At follow-up evaluation, no evidence of osteolysis or radiographic loosening was seen and the mean tibiofemoral angle was 4 degrees of valgus. This technique provides mid-term stable correction and excellent clinical and radiographic results in patients with severe varus deformity.
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ABSTRACT: Bony resection of the proximal medial tibia, an alternative technique for soft tissue balancing in total knee arthroplasty (TKA), was compared to the conventional medial soft tissue release technique. From June 2005 to June 2007, we performed 40 TKA in 27 patients with ≥10° tibio-femoral varus deformity. The conventional, medial soft tissue release technique was applied in 20 cases and bony resection of proximal medial tibia in the other 20 cases (vertical osteotomy group). Total operation time, knee range of motion (ROM), hospital for special surgery (HSS) scores, and tibio-femoral medial-lateral gap ratio in 0°, 90°, and 130° flexion at postoperative 6 months were compared between the groups. The total operation time was shorter in the vertical osteotomy group. Tibio-femoral medial-lateral gap ratio in 130° flexion was closer to 1 in the vertical osteotomy group (p=0.000). There was no significant difference in the ROM, HSS score, or tibio-femoral medial-lateral gap ratio in 0° and 90° flexion at postoperative 6 months. In severe varus knees, bony resection of proximal medial tibia can be considered as an alternative technique, in order to decrease total operation time and to obtain medial-lateral, soft-tissue balance in deep flexion.Knee surgery & related research. 03/2013; 25(1):13-18.
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ABSTRACT: We attempted to determine the degree of rotation of the femoral component to achieve an ideal rectangular flexion gap with minimal medial collateral ligament (MCL) release using a modified measured technique. Group I consisted of 60 osteoarthritis patients (72 cases) who underwent total knee arthroplasty (TKA) with minimal MCL release and Group II consisted of 48 patients without osteoarthritis (61 cases). We performed computed tomography (CT) scanning of the knee with 90 degree flexion in all of the patients and analyzed the angles between the distal femur landmarks and the tibial mechanical axis using a Picture Archiving Communication system. External rotation of the femoral component from the Whiteside line and posterior condylar line was measured in group I who underwent TKA with minimum MCL release. The variance in the mediolateral flexion gap according to the degree of rotation was also measured using an Auto-Computer Aided Design program. The CT scans showed that the Whiteside line, posterior condylar line, and transepicondylar line was more internally rotated on average from the longitudinal axis of tibia by 4.12°, 5.54°, and 4.64°, respectively, in group I compared to group II. In group I, the femoral component was inserted with an average external rotation of 5.6° from the posterior condylar line and with an average external rotation of 2.0° from the Whiteside line with minimal MCL release. From the measurements of the femoral component size and the variance in the degree of rotation using an Auto-CAD program, it was found that the change in the mediolateral flexion gap was greater when the rotation angle was greater and it was greater when the size of femoral component was larger at the same rotation angle. The average rotation angle of the femoral component to achieve an ideal rectangular flexion gap with minimal MCL release in TKA was an external rotation of 5.6° from the posterior condylar line and an external rotation of 2.0° from the Whiteside line. We concluded that when a femoral component is small in size, greater than average external rotation needs to be applied and when a femoral component is large in size, less than average external rotation needs to be applied.Knee surgery & related research. 09/2011; 23(3):153-8.
Article: Unstable Total Knee Arthroplasty[show abstract] [hide abstract]
ABSTRACT: Instability after total knee arthroplasty (TKA) is directly related with the success of an operation. It has been reported that about 10∼22% of revisions are caused by instability. The patient's satisfaction is diminished from the early stage of the postoperative period due to pain, recurrent swelling and difficulty when walking. Complications such as infection, wear and the loosening rate are also increased. There are many factors causing unstable TKA. Among the patients factors, neuromuscular pathology, other joint deformity and clinical obesity may play a role. These factors can be avoided by careful preoperative evaluation of patients. Yet the most common causes of instability are from the surgical technique, including the size of the implant, the alignment, gap balancing, soft tissue release and the patella tracking. Surgeons can achieve stable joint by performing a proper surgical procedure. Postoperatively trauma and overuse may provoke instability and patients can feel an unstable knee as a result of wear and loosening. Knee instability can be classified into the instability of flexion and extension, genu recurvatum and global instability. The first step to treat instability is to detect the causes of instability. The second step, of course, is to correct the causes. Either conservative treatment or revision surgery can be chosen according to the degree and causes of instability. Because the result of revision treatment is not as successful as primary TKA, careful evaluation of the patient as well as a meticulous surgical procedure should done for revision TKA.Journal of Arthroplasty - J ARTHROPLASTY. 01/2006; 21(4).