BACKGROUND Chronic large to massive rotator cuff tears are difficult to treat and re-tears are common even after surgical repair.We propose using a synthetic polypropylene mesh to increase the tensile strength of rota...BACKGROUND Chronic large to massive rotator cuff tears are difficult to treat and re-tears are common even after surgical repair.We propose using a synthetic polypropylene mesh to increase the tensile strength of rotator cuff repairs.We hypothesize that using a polypropylene mesh to bridge the repair of large rotator cuff tears will increase the ultimate failure load of the repair.AIM To investigate the mechanical properties of rotator cuff tears repaired with a polypropylene interposition graft in an ovine ex-vivo model.METHODS A 20 mm length of infraspinatus tendon was resected from fifteen fresh sheep shoulders to simulate a large tear.We used a polypropylene mesh as an interposition graft between the ends of the tendon for repair.In seven specimens,the mesh was secured to remnant tendon by continuous stitching while mattress stitches were used for eight specimens.Five specimens with an intact tendon were tested.The specimens underwent cyclic loading to determine the ultimate failure load and gap formation.RESULTS The mean gap formation after 3000 cycles was 1.67 mm in the continuous group,and 4.16 mm in the mattress group(P=0.001).The mean ultimate failure load was significantly higher at 549.2 N in the continuous group,426.4 N in the mattress group and 370 N in the intact group(P=0.003).CONCLUSION The use of a polypropylene mesh is biomechanically suitable as an interposition graft for large irreparable rotator cuff tears.展开更多
AIM To compare the measurements of knee rotation laxity by non-invasive skin pointer with a knee rotation jig in cadaveric knees against a skeletally mounted marker. METHODS Six pairs of cadaveric legs were mounted on...AIM To compare the measurements of knee rotation laxity by non-invasive skin pointer with a knee rotation jig in cadaveric knees against a skeletally mounted marker. METHODS Six pairs of cadaveric legs were mounted on a knee rotation jig. One Kirscher wire was driven into the tibial tubercle as a bone marker and a skin pointer was attached. Rotational forces of 3, 6 and 9 nm applied at 0°, 30°, 45°, 60° and 90° of knee flexion were analysed using the Pearson correlation coefficient and paired t-test. RESULTS Total rotation recorded with the skin pointer significantly correlated with the bone marker at 3 nm at 0°(skin pointer 23.9 ± 26.0° vs bone marker 16.3 ± 17.3°, r = 0.92; P = 0.0), 30°(41.7 ± 15.5° vs 33.1 ± 14.7°, r = 0.63; P = 0.037), 45°(49.0 ± 17.0° vs 40.3 ± 11.2°, r = 0.81; P = 0.002), 60°(45.7 ± 17.5° vs 34.7 ± 9.5°, r = 0.86; P = 0.001) and 90°(29.2 ± 10.9° vs 21.2 ± 6.8°, r = 0.69; P = 0.019) of knee flexion and 6 nm at 0°(51.1 ± 37.7° vs 38.6 ± 30.1°, r = 0.90; P = 0.0), 30°(64.6 ± 21.6° vs 54.3 ± 15.1°, r = 0.73; P = 0.011), 45°(67.7 ± 20.6° vs 55.5 ± 9.5°, r = 0.65; P = 0.029), 60°(62.9 ± 22.4° vs 45.8 ± 13.1°,r = 0.65; P = 0.031) and 90°(43.6 ± 17.6° vs 31.0 ± 6.3°, r = 0.62; P = 0.043) of knee flexion and at 9 nm at 0°(69.7 ± 40.0° vs 55.6 ± 30.6°, r = 0.86; P = 0.001) and 60°(74.5 ± 27.6° vs 57.1 ± 11.5°, r = 0.77; P = 0.006). No statistically significant correlation with 9 nm at 30°(79.2 ± 25.1° vs 66.9 ± 15.4°, r = 0.59; P = 0.055), 45°(80.7 ± 24.7° vs 65.5 ± 11.2°, r = 0.51; P = 0.11) and 90°(54.7 ± 21.1° vs 39.4 ± 8.2°, r = 0.55; P = 0.079). We recognize that 9 nm of torque may be not tolerated in vivo due to pain. Knee rotation was at its maximum at 45° of knee flexion and increased with increasing torque.CONCLUSION The skin pointer and knee rotation jig can be a reliable and simple means of quantifying knee rotational laxity with future clinical application.展开更多
文摘BACKGROUND Chronic large to massive rotator cuff tears are difficult to treat and re-tears are common even after surgical repair.We propose using a synthetic polypropylene mesh to increase the tensile strength of rotator cuff repairs.We hypothesize that using a polypropylene mesh to bridge the repair of large rotator cuff tears will increase the ultimate failure load of the repair.AIM To investigate the mechanical properties of rotator cuff tears repaired with a polypropylene interposition graft in an ovine ex-vivo model.METHODS A 20 mm length of infraspinatus tendon was resected from fifteen fresh sheep shoulders to simulate a large tear.We used a polypropylene mesh as an interposition graft between the ends of the tendon for repair.In seven specimens,the mesh was secured to remnant tendon by continuous stitching while mattress stitches were used for eight specimens.Five specimens with an intact tendon were tested.The specimens underwent cyclic loading to determine the ultimate failure load and gap formation.RESULTS The mean gap formation after 3000 cycles was 1.67 mm in the continuous group,and 4.16 mm in the mattress group(P=0.001).The mean ultimate failure load was significantly higher at 549.2 N in the continuous group,426.4 N in the mattress group and 370 N in the intact group(P=0.003).CONCLUSION The use of a polypropylene mesh is biomechanically suitable as an interposition graft for large irreparable rotator cuff tears.
文摘AIM To compare the measurements of knee rotation laxity by non-invasive skin pointer with a knee rotation jig in cadaveric knees against a skeletally mounted marker. METHODS Six pairs of cadaveric legs were mounted on a knee rotation jig. One Kirscher wire was driven into the tibial tubercle as a bone marker and a skin pointer was attached. Rotational forces of 3, 6 and 9 nm applied at 0°, 30°, 45°, 60° and 90° of knee flexion were analysed using the Pearson correlation coefficient and paired t-test. RESULTS Total rotation recorded with the skin pointer significantly correlated with the bone marker at 3 nm at 0°(skin pointer 23.9 ± 26.0° vs bone marker 16.3 ± 17.3°, r = 0.92; P = 0.0), 30°(41.7 ± 15.5° vs 33.1 ± 14.7°, r = 0.63; P = 0.037), 45°(49.0 ± 17.0° vs 40.3 ± 11.2°, r = 0.81; P = 0.002), 60°(45.7 ± 17.5° vs 34.7 ± 9.5°, r = 0.86; P = 0.001) and 90°(29.2 ± 10.9° vs 21.2 ± 6.8°, r = 0.69; P = 0.019) of knee flexion and 6 nm at 0°(51.1 ± 37.7° vs 38.6 ± 30.1°, r = 0.90; P = 0.0), 30°(64.6 ± 21.6° vs 54.3 ± 15.1°, r = 0.73; P = 0.011), 45°(67.7 ± 20.6° vs 55.5 ± 9.5°, r = 0.65; P = 0.029), 60°(62.9 ± 22.4° vs 45.8 ± 13.1°,r = 0.65; P = 0.031) and 90°(43.6 ± 17.6° vs 31.0 ± 6.3°, r = 0.62; P = 0.043) of knee flexion and at 9 nm at 0°(69.7 ± 40.0° vs 55.6 ± 30.6°, r = 0.86; P = 0.001) and 60°(74.5 ± 27.6° vs 57.1 ± 11.5°, r = 0.77; P = 0.006). No statistically significant correlation with 9 nm at 30°(79.2 ± 25.1° vs 66.9 ± 15.4°, r = 0.59; P = 0.055), 45°(80.7 ± 24.7° vs 65.5 ± 11.2°, r = 0.51; P = 0.11) and 90°(54.7 ± 21.1° vs 39.4 ± 8.2°, r = 0.55; P = 0.079). We recognize that 9 nm of torque may be not tolerated in vivo due to pain. Knee rotation was at its maximum at 45° of knee flexion and increased with increasing torque.CONCLUSION The skin pointer and knee rotation jig can be a reliable and simple means of quantifying knee rotational laxity with future clinical application.
