Comparison of Poly-L-Lactic Acid and Poly-L-Lactic Acid/Hydroxyapatite Bioabsorbable Screws for Tibial Fixation in ACL Reconstruction: Clinical and Magnetic Resonance Imaging Results

BACKGROUND: The purpose of this study was to compare the clinical and radiological results of 2 different tibial fixations performed using bioabsorbable screws with added hydroxyapatite (HA) and pure poly-L-lactic acid (PLLA) screws in anterior cruciate ligament (ACL) reconstruction. METHODS: A total of 394 patients who underwent arthroscopic ACL reconstruction between March 2009 and June 2012 were retrospectively reviewed. Of those, 172 patients who took the radiological and clinical evaluations at more than 2 years after surgery were enrolled and divided into 2 groups: PLLA group (n = 86) and PLLA-HA group (n = 86). Both groups were assessed by means of the Lysholm score, International Knee Documentation Committee (IKDC) subjective knee score, and Tegner activity score. Stability was evaluated using the KT-2000 arthrometer. Magnetic resonance imaging was performed to evaluate tibial tunnel widening, screw resorption, osteoingeration, and foreign body reactions. RESULTS: The PLLA-HA group showed significant reduction in the extent of tibial tunnel widening and foreign body reactions and significant increase in screw resorption compared to the pure PLLA group (p < 0.001 for both). In contrast, postoperative Lysholm score, Tegner activity score, IKDC score, and side-to-side difference on the KT-2000 arthrometer showed no significant differences between groups (p = 0.478, p = 0.906, p = 0.362, and p = 0.078, respectively). The PLLA group showed more significant widening in the proximal tibial tunnel than the PLLA-HA group (p = 0.001). In the correlation analysis, proximal tibial tunnel widening revealed a positive correlation with knee laxity (r = 0.866) and a negative correlation with Lysholm score (r = −0.753) (p < 0.01 for both). CONCLUSIONS: The HA added PLLA screws would be advantageous for tibial graft fixation by reducing tibial tunnel widening, improving osteointegration, and lowering foreign body reactions. Even though no clinically significant differences were noted between the pure PLLA group and PLLA-HA group, widening of the proximal area of the tibial tunnel showed a tendency to increase knee laxity measured using the KT-2000 arthrometer.

Comparison of Graft Patency Rates between the Diabetic and Non-diabetic Patients after Infrainguinal Arterial Bypasses

PURPOSE: It is well known that leg amputaions are more common in diabetic than non-diabetic patients with arterial occlusive disease. However, the previous reports comparing the graft patencies following infrainguinal bypasses between diabetic and non-diabetic patients revealed a wide range of variance. We tried to determine whether there is a difference on the graft patency between diabetic and non-diabetic patients with infrainguinal arterial bypasses. METHOD: During the period from March, 1993 to December, 1999, 271 infrainguinal bypass grafts were implanted to the limbs with chronic atherosclerotic arterial occlusive disease at Kyungpook National University Hospital, Taegu, Korea. Among them, 193 limbs with autogenous reversed vein grafts were included in this study, which comprised of 65 limbs (34%) in diabetic and 128 limbs (66%) in non-diabetic patients. To compare the graft patencies between diabetic and non-diabetic patients, we divided them into 3 groups according to the levels of distal anastomosis. We used life table or Kaplan-Meier methods to calculate the cumulative primary patency rates and log-rank test to compare the graft patencies between the groups. RESULT: The sites of distal anastomosis were above-knee popliteal artery in 29.2%, below-knee popliteal artery in 40.0%, and infrapopliteal artery in 30.8% of diabetic patients, whereas above-knee popliteal artery in 21.1%, below-knee popliteal artery in 50.0%, and infrapopliteal artery in 28.9% of non-diabetic patients. Vein grafts used in the bypasses were 185 reversed greater saphenous veins, 5 spliced veins, and 3 arm veins. The cumulative primary patency rates at 1, 3 and 5 years were 86% (SE 5.0%), 74% (SE 7.6%) and 74% (SE 7.6%) respectively, in diabetic patients, while 84% (SE 3.7%), 73% (SE 5.2%) and 56% (SE 9.8%) respectively, in non-diabetic patients group. After comparing the patency rates between 2 groups at 3 different levels of distal anastomosis, there was no statistically significant (p<0.05) difference at any level. CONCLLUSION: We found that diabetes did not affect the primary graft patency following the lower extremity arterial bypasses using reversed vein grafts.