Intraoperative soft tissue tension and postoperative range of motion in posterior stabilized total knee arthroplasty.

BACKGROUND: Intraoperative soft tissue tension can significantly impact the range of motion following total knee arthroplasty (TKA). However, the level of impact remains unclear. The purpose of this study was to investigate the relationship between intraoperative soft tissue tension and postoperative range of motion. METHODS: This retrospective study included 504 patients operated with posterior stabilized TKA. During surgery, we adjusted the soft tissue tension from 80 to 160 N for both flexion and extension with the tensor/balancer device and torque driver. Patients were grouped into three categories based on intraoperative soft tissue tension and analyzed with the 1-year postoperative range of motion using one-way analysis of variance (ANOVA). In addition, Pearson's correlation coefficients were determined to assess the association between intraoperative soft tissue tension and postoperative range of motion. RESULTS: The absolute tension value at 90° flexion did not affect the postoperative flexion angle (p = 0.61). The absolute tension value at 0° extension did not affect the postoperative extension angle (p = 0.91). Likewise, the difference of tension between flexion and extension did not affect the postoperative flexion angle (p = 0.86). All comparisons did not have the differences in sex, height, weight, body mass index, diagnosis and preoperative range of motion between three groups. No significant correlation was found in each comparison (r = 0.078, r = 0.031, r = -0.052, respectively). CONCLUSIONS: We did not observe a correlation between intraoperative soft tissue tension adjusted from 80 to 160 N and 1-year postoperative range of motion in posterior stabilized TKA.

Graft length change and radiographic assessment of femoral drill hole position for medial patellofemoral ligament reconstruction.

PURPOSE: Medial patellofemoral ligament (MPFL) reconstruction has been recognized as a useful treatment method for patella instability. However, the optimal fixation site has not been well investigated, and few reports have examined intraoperative graft length change. The purpose of the study is to evaluate the intraoperative graft length change and femoral drill hole position to find the optimal graft placement. METHODS: The graft length change between the two points on patella and femur was measured using Isotac(®) and Isometric Positioner(®) during passive knee motion in 27 cases of MPFL. The location of Isotac(®) was also evaluated on the 2-directional radiograph. The pre- and postoperative radiographic assessments have been done in order to evaluate the effect of MPFL reconstruction on patellofemoral alignment. RESULTS: There were 10 cases in which the distance between the two points became longer during knee flexion, 8 cases in which it became shorter and the remaining 9 cases in which the distance changed within 2 mm. The femoral drill hole position was assessed assuming that the maximum anterior-posterior (AP) diameter of the femur on the lateral radiograph was defined as 100%. The distance of the femoral tunnel position from the articular surface averaged 50% overall, 46% in the short group, 55% in the longer group and 48% in the isometric group (P < 0.001). Patella height seemingly affected the length change character. The intraoperative length change influenced the early recovery of knee range motion postoperatively. CONCLUSIONS: The femoral tunnel position is reaffirmed to be an essential determinant for the graft length change in the MPFL reconstruction. Both graft length change measurements and intraoperative radiographic assessment are practical for proper graft placement.

Isolated anterior cruciate ligament reconstruction in patients with chronic anterior cruciate ligament insufficiency combined with grade II valgus laxity.

BACKGROUND: There is no consensus about whether isolated anterior cruciate ligament reconstruction using multistrand hamstring tendon with nonoperative treatment for chronic medial collateral ligament injury is sufficient. PURPOSE: To assess clinical outcome for patients with chronic anterior cruciate ligament injury and accompanying grade II valgus laxity who received medial hamstring anterior cruciate ligament reconstruction alone. Results were compared with those of patients with isolated chronic anterior cruciate ligament injury without valgus laxity. STUDY DESIGN: Cohort study; Level of evidence, 2. METHODS: Two hundred eighty-nine patients with isolated anterior cruciate ligament injury were compared with 53 patients with accompanying valgus laxity (minimum follow-up, 24 months). The following parameters were compared between the 2 groups at the last follow-up: range of motion, KT-1000 arthrometer value, pivot-shift test result, Lysholm knee scale, knee extensor muscle strength, return to sporting activities, subjective recovery, and International Knee Documentation Committee grade. Differences in clinical outcome were evaluated between those with preoperative International Knee Documentation Committee grade B and grade C and between those with grade A and grade B or C at final evaluation. RESULTS: Postoperative KT-1000 arthrometer value averaged 1.2 mm for those with isolated anterior cruciate ligament injury and 1.6 mm for those with accompanying valgus laxity (not significant, P = .281). There was no significant difference between these 2 groups regarding the other items. In patients with preoperative valgus laxity, KT-1000 arthrometer values at final evaluation between patients with preoperative grade B and C were not significantly different. The value for subjects with grade A at final evaluation was 1.3 mm and for those with grade B or C at final evaluation was 2.7 mm (P = .065). CONCLUSION: There was no clinically significant difference regarding outcome of anterior cruciate ligament multistrand hamstring reconstruction alone for 90% of patients with grade II valgus laxity who regained medial stability with nonoperative management compared with those who underwent the same anterior cruciate ligament reconstruction for an isolated anterior cruciate ligament tear.

Electron microscopic evaluation of two-bundle anatomically reconstructed anterior cruciate ligament graft.

We investigated the difference in collagen fibrils in the two-bundle anatomically reconstructed anterior cruciate ligament (ACL) and the one-bundle reconstructed ACL. Ten patients with a two-bundle anatomically reconstructed ACL using semitendinosus tendons (Two-ST) were followed for an average of 16 months (7-27 months) and were compared with 15 patients with a one-bundle ACL (One-ST) reconstruction using hamstring tendons followed for an average of 20 months (9-39 months). Biopsy was performed during second-look arthroscopy. The diameter of the collagen fibrils, their density, and the percentage of collagen fibrils were measured using electron micrography. We also investigated biopsy specimens of normal semitendinosus and gracilis tendons from 10 patients. The diameter of the collagen fibrils from hamstring tendons in the Two-ST (45.1 +/- 7.6 nm) was significantly larger than that in the One-ST (40.1 +/- 7.8 nm) ( P < 0.05). The diameter of the collagen fibrils in the normal hamstring tendons was significantly larger than that in the reconstructed ACL with hamstring tendons of the Two-ST and One-ST groups ( P < 0.01). The results of the study revealed that the diameter of collagen fibrils in the Two-ST was significantly greater than that in the One-ST. Hence, the tensile strength of the two-bundle graft may be greater than that of the one-bundle graft.