Preoperative Varus-Valgus Stress Angle Difference Is Valuable for Predicting the Extent of Medial Release in Varus Deformity during Total Knee Arthroplasty

PURPOSE: The purpose of this study was to compare the predictive value of the valgus stress angle (SA), varus SA and varus-valgus SA difference (VVD) in predicting the degree of medial release in varus deformity during total knee arthroplasty (TKA). MATERIALS AND METHODS: One hundred eight TKAs (78 patients), which were performed in primary osteoarthritis with varus knee deformity, were retrospectively classified into three groups according to the degree of medial release (group A, mild release; group B, moderate release; and group C, severe release). Medical charts were reviewed, and long weight bearing standing anteroposterior radiographs and varus-valgus stress radiographs were evaluated. RESULTS: The valgus SA was significantly different between group A and B and between group A and C. However, it was not significantly different between group B and C. The varus SA was significantly different between group B and C and between group A and C. However, it was not significantly different between group A and B. The VVD was significantly different in all intergroup comparisons. CONCLUSIONS: Evaluation of the VVD is more valuable in predicting the degree of medial release in TKA performed in varus knee deformity than evaluation of the simple valgus and varus SA.

Relationship between Tibial Bone Defect and Extent of Medial Release in Total Knee Arthroplasty

PURPOSE: To understand the relationship between tibial bone defect and extent of medial release in total knee arthroplasty. MATERIALS AND METHODS: We evaluated 32 knees in 22 patients with variable degrees of tibial bone defect on medial plateau has undergone total knee arthroplasty. In this study, 31 cases had been diagnosed as degenerative osteoarthritis and 1 case was osteonecrosis. We excluded cases with infection, traumatic arthritis, or neuropathic joints. With regard to gender, 29 cases were female and 3 cases were male. The following relationships were analyzed: preoperative degrees of tibial bone defect and varus deformity; the femorotibial angle of both weight-bearing whole extremity radiogram, distractive stress radiogram, and the extent of medial release. RESULTS: Average tibial bone defect was 9.8+/-4.1 mm. Average femorotibial angle on weight-bearing whole extremity radiograph was varus 10.0degrees+/-6.2degrees. Average femorotibial angle on distractive stress radiograph was varus 0.7degrees+/-4.6degrees. Statistically the extent of medial release showed no significant relationship with the degree of tibial bone defect and femoro-tibial angle of whole extremity radiogram. However, it revealed a statistically significant relationship with the femorotibial angle on distractive radiogram (r=0.465, p=0.007). CONCLUSIONS: Preoperative distractive stress radiograph might be a useful method to predict the extent of intraoperative medial release during total knee arthroplasty.

Utility of Preoperative Distractive Stress Radiograph for Beginners to Extent of Medial Release in Total Knee Arthroplasty

BACKGROUND: This study evaluated the preoperative distractive stress radiographs in order to quantify and predict the extent of medial release according to the degree of varus deformity in primary total knee arthroplasty. METHODS: We evaluated 120 varus, osteoarthritic knee joints (75 patients). The association of the angle on the distractive stress radiograph with extent of medial release was analyzed. The extent of medial release was classified into the following 4 groups according to the stage: release of the deep medial collateral ligament (group 1), release of the posterior oblique ligament and/or semimembranous tendon (group 2), release of the posterior capsule (group 3) and release of the superficial medial collateral ligament (group 4). RESULTS: The mean femorotibial angle on the preoperative distractive stress radiograph was valgus 2.4degrees (group 1), valgus 0.8degrees (group 2), varus 2.1degrees (group 3) and varus 2.7degrees (group 4). The extent of medial release increased with increasing degree of varus deformity seen on the preoperative distractive stress radiograph. CONCLUSIONS: The preoperative distractive stress radiograph was useful for predicting the extent of medial release when performing primary total knee arthroplaty.

Unicompartmental knee arthroplasty for single compartmental knee disease / 中国矫形外科杂志

[Objective] To analyze the cases performed by unicompartmental knee arthroplasty in order to assess the early outcome,and to discuss the indications and the key points of surgical technique.[Methods]Under the principle of "slight undercorrection",15 patients were performed by unicompartmental knee arthoplasty with the technique of limited medial release if necessary.The HSS score,the fomeral tibial angle and the maxima degree of flexion and extension measured preoperatively and in the latest follow-up were analyzed by SPSS 13.0 with the method of paired t test.Meanwhile the angle of the posterior slope of the tibial implants was measured.[Results]Postoperatively the HSS score,the fomeral tibial angle and the maxima degree of flexion and extension were improved significantly in the latest follow-up,and the average angle of the posterior slope of the tibial implants was 4.2 degrees.[Conclusion]Unicompartmental knee arthroplasty has a satisfing early outcome.And it is very important to carry out the indications strictly.With the surgical technique of limited medial release,the flexional contracture could also be improved significantly.

Clinical and Radiological Evaluation of Detached MCL cases in Medial Release During TKA: MCL detached vs stable CR vs stable PS

PURPOSE: On performing TKA in severe varus deformity, sometimes processing medial release, we can not get well balanced knee without completely detaching the MCL in tibial attached site. In these cases, we analyzed the clinical and radiological results. MATERIALS AND METHODS: We evaluated 20 TKA patients with completely detached MCL (Group I) comparing to 20 TKA patients without MCL detached using CR type(Group II), 20 TKA patients without MCL detaches using PS type(Group III). The clinical evaluation was done by the American Knee Society evaluation system. The radiographic examination in valgus stress were done with Telos device under control of fluoroscopic guide 0 degree and 30 degree flexion. RESULTS: The mean knee score of each group was improved from 43, 45, and 41 points preoperatively to 89, 90, and 91, then mean functional score also improved from 52, 54, and 57 points preoperatively to 88, 91 and 94 points at the latest follow-up respectively. On the radiographs in valgus stress at 0 degree flexion and 30 degree flexion, the mean angle were; in group I 4.5 and 6.0 degree, in group II 3.1 and 4.2 degree, in group III 3.4 and 4.7 degree. There was no patients to complain the subjective medial instability of the knee. CONCLUSION: On performing TKA in severe varus deformity, in releasing MCL, it might be detached completely from tibial side. In this situation, this resulted in good function and there was no need to reattach the ligament and use constrained type prosthesis.