Search

Obtaining a correct postoperative limb alignment is an important factor in achieving a successful clinical outcome after an opening-wedge high tibial osteotomy (OWHTO). To better predict some of the aspects that impact upon the clinical outcomes following this procedure, including postoperative correction loss and over correction, we examined the changes in the frontal plane of the lower limb in a cohort of patients who had undergone OWHTO using radiography. Forty-two knees from 33 patients (23 cases of osteoarthritis and 10 of osteonecrosis) underwent a valgus realignment OWHTO procedure and were radiographically assessed for changes that occurred pre- and post-surgery. The mean femorotibial angle (FTA) was found to be 182.1 +/- 2.0 degrees (12 +/- 2.0 anatomical varus angulation) preoperatively and 169.6 +/- 2.4 degrees (10.4 +/- 2.4 anatomical valgus angulation) postoperatively. These measurements thus revealed significant changes in the weight bearing line ratio (WBL), femoral axis angle (FA), tibial axis angle (TA), tibia plateau angle (TP), tibia vara angle (TV) and talar tilt angle (TT) following OWHTO. In contrast, no significant change was found in the weight bearing line angle (WBLA) after these treatments. To assess the relationship between the correction angle and these indexes, 42 knees were divided into the following three groups according to the postoperative FTA; a normal correction group (168 degrees < or = FTA < or = 172 degrees ), an over-correction group (FTA < 168 degrees ), and an under-correction group (FTA > 172 degrees ). There were significant differences in the delta angle [DA; calculated as (pre FTA - post FTA) - (pre TV - post TV)] among each group of patients. Our results thus indicate a negative correlation between the DA and preoperative TA (R(2) = 0.148, p < 0.05). Hence, given that the correction errors in our patients appear to negatively correlate with the preoperative TA, postoperative malalignments are likely to be predictable prior to surgery. [ABSTRACT FROM AUTHOR]

We evaluated the clinical outcomes, in terms of early weight bearing, of using opening wedge high tibial osteotomy (OWHTO) to treat spontaneous osteonecrosis of the medial femoral condyle of the knee (SONK) using TomoFix and artificial bone substitute. Damaged cartilage tissue was removed and drilling of the necrotic area followed by OWHTO was performed in 30 knees from 30 patients with an average age of 71 years (range 58-82) at the time of operation. Patients were allowed to undertake partial weight-bearing exercises 1 week after the osteotomy procedure, with all patients performing full weight-bearing exercise at 2 weeks post-surgery. The mean follow-up period was 40 months (range 24-62). All of the SONK patients could walk with a full weight-bearing load, using only a T-cane, at 2 weeks after undergoing OWHTO. Clinical assays, including the mean American Knee Society Score and Function Score, showed significant improvements from 51 to 93 points, and 58 to 93 points, respectively. Prior to surgery, the average femoro-tibial angle (FTA) during standing was 181 (1 degree anatomical varus) and had significantly changed to 170 (10 degrees valgus) at the time of follow-up. There were no cases of non-union, or implant failure in any of our patients. In addition, none of the patients could sit in the Japanese style prior to surgery, but 21 of 30 patients (70%) could do so after treatment. Arthroscopic findings could be observed in 24 out of 30 cases at implant removal. Necrotic area in each case was covered with fibrous cartilage-like tissue completely. Drilling of the necrotic area followed by OWHTO with TomoFix and artificial bone substitute is an effective treatment for SONK as it results in pain alleviation and regeneration of the fibrous cartilage tissue over the necrotic legion. In addition, an early weight-bearing exercise program is possible after this procedure and full weight-bearing can be achieved at two weeks after surgery. [ABSTRACT FROM AUTHOR]

Positron-emission tomography (PET) imaging has several advantages over conventional scintigraphy, including a high spatial resolution and the ability to quantify disease progression. Recently, (18)F-fluoride PET has been applied to the evaluation of malignant tumors and musculoskeletal disorders. In our current study, spontaneous osteonecrosis of the knee (SONK) was visualized using this technique. We determined whether PET images can reveal SONK lesions, whether there were significant differences in the maximum standardized uptake value (SUVmax) among each of the SONK stages, and finally if there was any correlation between the maximum SUVmax value and size of the SONK lesion measured both by radiography and MRI. Fourteen knees from 13 patients diagnosed with SONK were imaged using a PET scanner. In all cases, PET showed an accumulation of 18F-fluoride in the medial condyle. The SUVmax ranged from 8.6 to 23.7 with an average of 15.1 +/- 3.7 and was measured at different disease stages with an average of 12.4 +/- 5.9 in Stage 2 (n = 5), 16.3 +/- 1.4 in Stage 3 (n = 4), and 16.8 +/- 4.3 (n = 5) in Stage 4 lesions. There were no significant differences in these measurements between the SONK stages. However, a significant positive correlation between the SUVmax and lesion size, including the surface area of the lesion (r2 = 0.692, P = 0.0002) and the condyle width ratio (r2 = 0.365, P = 0.022), was found. The approximate volumes of the lesions measured by MRI had an average of 4.8 +/- 3.1 cm3, and also showed a significant correlation with the SUVmax (r2 = 0.853, P < 0.0001). Hence, our present results indicate that a high SUV is indicative of a large SONK lesion. [ABSTRACT FROM AUTHOR]