Angiotensin II blockade had no effect on range of motion after total knee arthroplasty: a retrospective review.

BACKGROUND: Stiffness and pain from arthrofibrosis following total knee arthroplasty (TKA) is a challenging problem, and investigating methods to prevent or reduce the incidence of postoperative arthrofibrosis is critical. Studies have shown that angiotensin-converting enzyme inhibitors (ACEIs) and angiotensin receptor blockers (ARBs) are efficacious at preventing fibrotic disorders in the lungs, liver, kidneys, and eyes. Our aim was to determine if ACEI or ARB use postoperatively reduces the incidence of arthrofibrosis in TKA patients. METHODS: In a retrospective review, we analyzed 141 consecutive TKAs performed at a single institution by a single surgeon from December 2010 to December 2014. Range of motion (ROM) in patients already taking ACEI, ARB, or neither medication was compared. Independent variables recorded were gender, age, BMI, presence of diabetes or preoperative opioid or statin use, preoperative ROM, and use of ACEIs or ARBs. Dependent variables recorded were postoperative knee flexion, extension, and total arc of motion. The primary outcome variable was success or failure of achieving 118o total arc of motion postoperatively, based on a study that found significant compromise of function in TKA patients who failed to obtain this goal. Secondary endpoints were postoperative knee flexion, extension, and total arc of motion. RESULTS: The use of neither ACEIs nor ARBs showed a significant difference in attaining greater than 118° of motion postoperatively compared to controls at 6 months. Significant predictors of obtaining > 118° motion were BMI (p < 0.05), preoperative flexion (p < 0.001), and preoperative total arc of motion (p < 0.002). Significant predictors of secondary ROM outcomes were preoperative ROM and BMI. CONCLUSIONS: Our study demonstrated that the principle predictor of postoperative ROM is BMI and preoperative ROM. The use of ACEIs or ARBs did not result in a greater likelihood of obtaining satisfactory ROM postoperatively.

A biomechanical comparison of all-inside cruciate ligament graft preparation techniques.

BACKGROUND: The all-inside cruciate ligament graft preparation technique has become popular due to its utility in sparing a growing physis, preserving a tendon in ACL surgery, and/or reduction of pain. However, few studies have compared graft preparation techniques to determine the ideal construct for cruciate ligament reconstruction. We sought to compare biomechanical properties of two quadrupled all-inside cruciate ligament graft preparation techniques and three alternative all-inside graft preparation techniques that may be used when the available tendon is too short to be quadrupled. METHODS: Fifty porcine extensor tendons were evenly divided into five groups (n = 10) representing all-inside graft preparation techniques, including two quadrupled (Quad-A, Quad-B) and three alternative methods (Tripled, Folded, Two-Doubled). Each graft construct underwent preconditioning (10 loading cycles from 20 to 50 N at 0.1 Hz), cyclic loading (500 loading cycles from 50 to 250 N at 1.0 Hz) and load-to-failure (tension applied at 20 mm/min). RESULTS: Quad-A and Quad-B demonstrated no significant differences in cyclic displacement (10.5 ± 0.3 vs 11.7 ± 0.4 mm; p = 0.915), cyclic stiffness (1086.2 ± 487.3 vs 460.4 ± 71.4 N/mm; p = 0.290), pullout stiffness (15.9 ± 4.3 vs 7.4 ± 4.4 N/mm; p = 0.443), ultimate failure load (641.2 ± 84.7 vs 405.9 ± 237.4 N; p = 0.672), or ultimate failure displacement (47.3 ± 6.7 vs 55.5 ± 0.7 mm; p = 0.778). The mean cyclic displacement of the Two-Doubled group was significantly greater than the Quad-A (29.7 ± 2.2 vs 10.5 ± 0.3 mm; p < 0.001), Quad-B (29.7 ± 2.2 vs 11.7 ± 0.4 mm; p < 0.001), Tripled (29.7 ± 2.2 vs 11.3 ± 0.2 mm; p < 0.001), and Folded group (29.7 ± 2.2 vs 13.3 ± 0.2 mm; p < 0.001). There were no other statistically significant differences between the three alternative all-inside graft preparation techniques. CONCLUSION: The current study demonstrates the biomechanical properties of two quadrupled all-inside graft constructs, Quad-A and Quad-B, are not significantly different. When the available tendon is of insufficient length, the Two-Doubled group demonstrated more than twice the cyclic displacement of all other graft preparation techniques, and is therefore not recommended for use in all-inside cruciate ligament reconstruction.