Factors that Predicts the Size of Autologous Hamstring Tendon Graft for Double-Bundle ACL Reconstruction.

BACKGROUND: To evaluate the effectiveness of demographic data and radiographic measurements for predicting the diameter and length of autologous semitendinosus (ST) and gracilis (GR) graft. MATERIALS AND METHODS: Fifty-four cases were included to measure the size of 3 or 4 strands of ST and GR tendons retrospectively. The hamstring length on radiograph was defined as the length from the lowest point of ischial tuberosity to intercondylar notch of the femur. The linear and logistic regression analysis was used to assess the roles of the predictor variables, as demographic and radiologic data, in the outcome variables, as diameter of tendon grafts. The cross-validation with hold-out samples and concordance correlation coefficient (CCC) were also calculated. RESULTS: The hamstring and leg length measurement and gender were associated with the diameter of 4-stranded ST tendon graft. The hamstring length measurement, age and BMI were the factors associated with the diameter of 3-stranded ST tendon graft. The hamstring length measurement was found as a common factor for predicting diameters of hamstring tendon with reliable predictability. Moreover, the equation of multivariate regression analysis for the diameter of 4-stranded ST tendon graft showed the most validated power of prediction. All of the cross-validated R 2 values were calculated as similar results of multivariate model, but CCC between the measured diameter and estimated value on the predictive equation showed moderate agreement only (CCC = 0.694). CONCLUSIONS: Combining radiographic length measurements with demographic data showed reliable prediction in identifying the risk of inappropriate graft diameters. LEVEL OF EVIDENCE: Level IV retrospective cohort study.

Factors associated with discrepancies between preoperatively planned and postoperative alignments in patients undergoing closed-wedge high tibial osteotomy.

BACKGROUND: To evaluate the difference between preoperative plan and postoperative alignment after closed-wedge HTO and determine factors associated with difference. METHODS: This retrospective cohort study included 165 cases with closed-wedge HTO. The following radiographic parameters were measured: mechanical tibiofemoral angle (mTFA), mechanical medial proximal tibial angle (MPTA), joint line convergence angle, mediolateral joint width discrepancy, Kellgren-Lawrence (K-L) grade, and discrepancy between the correction angle in tibia and correction angle in mTFA. The linear regression analysis was used for the preoperative factors that affect the discrepancy between correction angle in tibia and correction angle in mTFA. RESULTS: Preoperative and postoperative mTFA was varus 8.3°±3.7 and valgus 3.1°±2.6. The MPTA was varus 6.2°±3.1 preoperatively, valgus 3.7°±3.0 postoperatively. The mediolateral joint width discrepancy was 3.1mm±1.8 preoperatively and 1.8mm±1.4 postoperatively. The discrepancy between correction angle in tibia and correction angle in mTFA was 1.5°±2.3 valgus. By regression analysis, one degree of valgus overcorrection was found to be related with every 2.5° of joint convergence angle (r2=0.396), 2.4mm of mediolateral joint width discrepancy (r2=0.310) and increased one grade of K-L classification (r2=0.107) as preoperative measurement. CONCLUSIONS: The 1.5° valgus overcorrection of postoperative mTFA was found compared with planned correction angle in tibia. By the equation, every 2.5° of joint convergence angle and 2.4mm of mediolateral joint width discrepancy preoperatively could predict one degree of valgus overcorrection.

What is the Ideal Degree of Extension After Primary Total Knee Arthroplasty?

BACKGROUND: Few studies have examined flexion contracture at the time of primary total knee arthroplasty (TKA) or how flexion contracture changes over time. The purpose of this study was to assess the ideal degree of extension immediately after TKA and to document postoperative changes in extension and clinical outcomes over 5-year follow-up. METHODS: This retrospective cohort study included 215 cases of primary TKA. Radiographic evaluations were performed on sagittal radiographs with the patient in the supine position and the knee in gravity and in passive extension using a stress device. Clinical outcomes were also measured. Four groups were defined on the basis of the extension angle during radiological evaluation: group 1, -10° to 0°; group 2, >0° to +5°; group 3, >+5° to +10°; group 4, >+10° in gravity. RESULTS: There were statistically significant differences in passive extension and gravity extension angles in groups 1, 3, and 4 with time-dependent and time*group (passive vs gravity) analyses, but not in group 2. The flexion contracture angles over 10° in gravity were decreased, although over 5° of flexion contracture remained at the final follow-up. Clinical outcomes were worse in groups 1 and 4 at the final follow-up. CONCLUSION: An extension angle between 0° and 5° in the passive extension position immediately after TKA can be considered ideal up to 5 years of follow-up. Patients with flexion contracture greater than 5° in passive extension and patients with hyperextension should be followed up to assess whether the condition will worsen.

Extent of vertical cementing as a predictive factor for radiolucency in revision total knee arthroplasty.

PURPOSE: Limited information is available regarding the effects of cementing extent on implant stability in patients who have undergone revision total knee arthroplasty (TKA). As such, the goals of this study were: (1) to determine the correlation between the extent of vertical cementing and implant loosening; (2) to determine whether the extent of cementing is a potential predictive factor for radiolucency; and (3) to evaluate the minimal amount of cement needed for a stable implant during revision TKA using a hybrid technique. METHODS: One hundred nine stemmed/revision TKAs with a mean follow-up period of 5 years were retrospectively analysed. In each case, a single varus-valgus constrained implant was used and fixed with a hybrid technique. Implant stability was evaluated according to the modified Knee Society radiographic scoring system. The extent of vertical cementing was defined as the longitudinal length from the implant base to the end of the radiopaque line around the stem on radiograph. Its correlation with implant stability was analysed, and the minimal value for a stable implant was evaluated with a receiver operating characteristic (ROC) analysis. RESULTS: The mean extent of vertical cementing was longer in stable implants (femur: p = 0.001, tibia: p = 0.004) and significantly correlated with implant stability (femur: p < 0.001, tibia: p = 0.001). A logistic regression analysis revealed that the risk of loosening was 8.7-16.1 times higher when the extent of cementing was <40 mm, which was located at the stem-implant junction of the modular implant. The minimal extent of vertical cementing was estimated to be 60 mm for a stable femoral implant and 50 mm for a tibial implant. CONCLUSIONS: The hybrid fixation technique with a cementing extent >60 mm for the femur and 50 mm for the tibia was durable at a mean follow-up period of 5 years. Vertical cementing 10-20 mm above the stem-implant junction is recommended when performing revision TKA using this technique. LEVEL OF EVIDENCE: IV.

Comparison of patellar resurfacing versus preservation in high flexion total knee arthroplasty.

PURPOSE: Recently, high flexion design total knee arthroplasty (TKA) has been introduced to improve clinical outcomes. The purpose of this study is to compare the midterm outcomes between patellar resurfacing (PR) and patellar preservation (PP) in high flexion TKA. METHODS: A total of 373 knees of primary TKAs were performed using high flexion design, 339 knees involved PR group and 34 knees involved PP group. After applying exclusion criteria, 1:3 matching was performed by the matching criteria. After matching, 69 knees in PR group and 23 knees in PP group remained. Radiographic outcomes, clinical outcomes, patients' satisfaction, ability and pain related to the high flexion activities were also evaluated. RESULTS: There was no significant difference in radiograph measurements, KS function score and WOMAC score (n.s). However, PR group showed better outcomes in KS knee score (P = 0.001) and HSS score (P = 0.03). There was no significant difference in postoperative satisfaction and ability of high flexion activities between the groups, but the pain at the high flexion activities in PP group was worse than that in PR group. CONCLUSION: In high flexion design of TKA, PR resulted in better midterm outcomes in regard to KS knee score, HSS score and knee pain related to the high flexion activities. The selective PR is recommended when performing primary TKA with high flexion design. LEVEL OF EVIDENCE: IV.

Normal sagittal of the anterior cruciate ligament can be reproduced using accessory anteromedial portal technique: a magnetic resonance imaging study.

INTRODUCTION: Over time, the need for anatomic anterior cruciate ligament (ACL) to restore normal kinematics and postoperative function of the knee has been accepted. The purpose of this study was to compare the sagittal alignment of reconstructed ACL, which is performed between transtibial (TT) technique and accessory anteromedial (AAM) portal technique and between the reconstructed and the normal side in the same patient. In addition, we used the head of a metallic femoral interference screw as a reference to measure the femoral tunnel position. PATIENTS AND METHODS: This was a retrospective study with 15 patients in each group: accessory anteromedial portal technique (n = 15), TT technique (n = 15) and contralateral normal side of each technique group (15 knees per technique). Magnetic resonance images of the ACL sagittal angle and radiographs of the coronal screw angle were used for comparing the two groups. The paired t test was used to compare operated and contralateral normal knee and independent t test was used to compare the TT and the AAM groups. RESULTS: The sagittal angle of ACL of AAM technique (51.6 ± 3.3°) was not different from the normal side (50.8 ± 2.1°) (P = 0.270), however that of the TT technique (59.9 ± 5.7°) was significantly different from the normal side (50.9 ± 2.4°) (P < 0.001). The sagittal angle of AAM technique was significantly lower than that of the TT technique (P < 0.001). The coronal angle of the screw to axis of the femur in AAM technique (51.7 ± 3.8°) was more horizontal than that of the TT technique (24.4 ± 8.9°) (P < 0.001). The center of the screw head of the AAM technique was 30.7 ± 3.1 % of the Blumensaat line and 39.2 ± 5.2 % of the condylar height. CONCLUSION: The anatomic sagittal angle of ACL can be achieved using the AAM technique compared with the TT technique. In addition, the angle of the screw in coronal plane was more horizontal using the AAM technique than with use of the TT technique. LEVEL OF EVIDENCE: Level III, diagnostic study.

Transphyseal anterior cruciate ligament reconstruction in a skeletally immature knee using anterior tibialis allograft.

Anterior cruciate ligament (ACL) injury in the skeletally immature individual is being recognized with increasing frequency. Nonoperative treatment of ACL injuries in skeletally immature patients have not been favorable. Surgical treatment options for complete ACL tears include primary ligament repair, extraarticular tenodesis, transphyseal reconstruction, partial transphyseal reconstruction, and physeal-sparing reconstruction. The advantage of transphyseal reconstruction is placement of the graft tissue in an isometric position, which provides better results, according to the literature. The potential disadvantage is angular or limb-length discrepancy caused by physeal violation. Controversy exists in allograft selection about whether bone or soft tissue passes into physes. The use of standard tunnels provides reliable results, but carries the risk of iatrogenic growth disturbance from physeal injury.This article presents 4 cases of transphyseal ACL reconstruction using anterior tibialis allograft in skeletally immature patients that had satisfactory functional outcomes with no growth disturbances. This is the first report of transphyseal ACL reconstruction using anterior tibialis allograft in skeletally immature patients in the English-speaking literature. All patients underwent transphyseal ACL reconstruction using anterior tibialis tendon allograft. None of the patients had angular deformities. No early physeal arrest was measured between the preoperative and postoperative radiographs. At last follow-up, the results of the Lachman test were normal for 3 patients and nearly normal for 1 patient. All patients demonstrated full range of knee motion (comparing the reconstructed knee to the contralateral knee). The results of the pivot-shift test were normal for 3 patients and nearly normal for 1 patient. No patients reported giving way.

Long-term survivals of stage IIb osteosarcoma: a 20-year experience in a single institution.

BACKGROUND: The purpose of this study is to evaluate the disease-free survival (DFS) and overall survival (OS) of patients with stage IIB osteosarcoma at a single institution for 20 years and to compare the results according to the chemotherapy protocols. METHODS: From Jan 1988 to Nov 2008, 167 patients with osteosarcoma were treated at our hospital and among them, 117 patients (67 males and 50 females) with stage IIB osteosarcoma were evaluable. Their mean age was 22.6 years (range, 8 months to 71 years). Seventy-eight cases underwent the modified T10 (M-T10) protocol (group 1), 23 cases underwent the T20 protocol (group 2) and 16 cases underwent the T12 protocol (group 3). The DFS and OS were calculated and compared according to the chemotherapy protocols. RESULTS: At a mean follow-up of 78.9 months, 63 patients were continuously disease-free (63/117), 6 patients were alive after having metastatic lesions, 7 patients died of other cause and 41 patients died of their disease. The 5- and 10-year OS rates were 60.2% and 44.8%, respectively and the 5- and 10-year DFS rates were 53.5% and 41.4%, respectively. There was no significant difference of the OS and DFS between the chemotherapy protocols (p = 0.692, p = 0.113). CONCLUSIONS: At present, we achieved success rates close to the internationally accepted DFS and OS. We were able to achieve the higher survival rates using the M-T10 protocol over the 20 years. However, there was no significant difference of results between the chemotherapy protocols. We think the M-T10 protocol will achieve more favorable results in the near future.

The impact of amount of bone resection on uncemented prosthesis failure in patients with a distal femoral tumor.

BACKGROUND AND OBJECTIVES: Previous reports on the correlation between the amount of bone resection and prosthetic failure might be confounded by variability in the amount of soft tissue resected and by the mode of prosthesis fixation. METHODS: We analyzed 117 patients who underwent intra-articular resection and cementless modular tumor prosthetic reconstruction for a distal femoral tumor. Mean follow-up duration was 95 months (range, 15-271 months). Associations between the prognostic variables and prosthesis survival were assessed. A receiver operating characteristic (ROC) curve was plotted for resection percentage to predict prosthetic failure. RESULTS: Prostheses were removed in 35 (30%) patients for; infection (17), local recurrence (5), loosening (7), stem fracture (4), or periprosthetic fracture (2). The 10-year prosthetic survivals of the 117 implants were 65.2 ± 5.4%. A percentage bone resection (>40%) was found to be associated with mechanical prosthesis failure by multivariate analysis (P = 0.003). ROC curve analysis demonstrated that an optimal cut-off point of 43% for resection percentage had a sensitivity of 95.9% and a specificity of 45.5% for predicting mechanical prosthesis failure. CONCLUSIONS: Infection is the major cause of prosthetic failure, and amount of bone resection is negatively correlated with implant longevity.

A 9-month-old phosphaturic mesenchymal tumor mimicking the intractable rickets.

Phosphaturic mesenchymal tumor is an extremely rare disease and is frequently associated with oncogenic osteomalacia showing paraneoplastic syndrome, which is characterized by phosphaturia, hypophosphatemia, normocalcemia, and decreased levels of 1,25-dihydroxyvitamin D3 associated with a tumor. A 2-year-old boy, who had a soft tissue tumor on his right thigh and previously diagnosed as myositis ossificans at 9-months-old, was presented with rachitic rosary and mildly enlarged tumor. Biochemical investigations showed hypophosphatemia, hyperphosphaturia, and an increased alkaline phosphatase level of 440 U/l (25-100 U/l), suggesting rickets, which was resistant to vitamin D dietary supplementation. We were certain of intractable rickets because of oncogenic hypophosphatemia and thus decided to excise the soft tissue mass. We observed laboratory improvement of rickets after 2 weeks. On the basis of surgical and histopathological examinations, the tumor was finally diagnosed as the phosphaturic mesenchymal tumor.

Osteosarcoma of the patella: biologic reconstruction with allograft.

Osteosarcoma rarely occurs in the patella. The majority of lesions located in the patella are usually benign. According to the literature, osteosarcoma of the patella has been reported in 32 cases. Surgical treatment (patellectomy, resection and arthrodesis with allograft, and total joint replacement) was attempted in several cases, but neither function of the knee joint nor prognosis of the patients were good. A 53-year-old woman reported pain and swelling in the left knee. Based on plain radiographs and magnetic resonance imaging (MRI), a bone tumor was suspected, and an open bone biopsy of the patella was performed. The pathologic diagnosis was osteoblastic osteosarcoma. A total patellectomy was performed because MRI showed a lesion that did not spread into the joint. A reconstruction was subsequently performed by allograft patella. The graft consisted of a quadriceps tendon, a patella with a patellar tendon, and the medial and lateral retinacula. Twenty-six months postoperatively, the function of the knee joint was almost similar to that before the procedure, and there was no evidence of recurrence or metastasis. After the procedure, the patient could walk without pain and the knee joint could flex to 140 degrees with extension lag of 10 degrees . To our knowledge, this is the first report of a biologic reconstruction with allograft patella after total patellectomy in osteosarcoma involving the patella.