Distraction-Neural Lengthening of Rabbit Sciatic Nerve by Tissue Expansion Technique / 대한정형외과연구학회지

PURPOSE: To determine the upper limit of peripheral nerve lengthening without loss of function, the recovery time of peripheral nerve palsy due to nerve lengthening and their histological changes. MATERIALS AND METHODS: Twelve adult New Zealand rabbits weighing about 2.5 kg were assigned to the following groups. Group 1 (n=6) was subjected to slow tissue expansion with 30% of nerve lengthening while group 2 (n=6) was rapid expansion with 40% lengthening of nerve. The expanders were refilled every 2 times during the 2nd and 4th weeks making a total four times of expansion. The rabbits were assessed in terms of affected leg paralysis, neural length gain, EMG with nerve conduction velocity and histological changes. RESULTS: In group 1 (n=6), paralysis on affected leg was found in one rabbit and was recovered spontaneously on the 4th weeks after expander removal. In Group 2 (n=6), paralysis was found in four rabbits, and three of them were recovered on 4, 5 and 9 weeks after removal of the expander. EMG study showed increase in distal latency of 2.50+/- 0.20 m/sec, and decrease in nerve conduction velocity of 62.49+/- 5.30 m/sec compared to normal side with 1.89+/- 0.14 m/sec and 75.39+/- 7.82 m/sec. The mean neural length gain was 6 mm (30% of 20 mm of initial pre-experimental nerve length) in group 1 and 8 mm (40% of 20 mm) in group 2. Light microscopic examination revealed the loss of segmental myelination, decrease of myelination, and vacuolation. Electron microscopic examination showed that the normal ring shaped contour of axon was changed to convoluted shape.

Simultaneous Pigmented Villonodular Synovitis and Synovial Chondromatosis in the Ankle Joint / 대한정형외과학회잡지

Pigmented villonodular synovitis and synovial chondromatosis are known as a poup of interrelated tumorous disorders that involve the lining of the joints, hursa and tendon sheath. Pigmented villonodular synovitis consists of proliferatin synovia1 tissue containing histiocytes, librohlasts, multinucleated giant cells, and capillaries that can destroy dense fihrous tissue, form soft tissue masses, and invade bone. Synovial chondromatosis consists of hyaline cartilage nodules within the synovium and synovial joint cavities, develop multiple loose fragments of cartilage within the joint. They may represent a reactive inflammatory process or henign neoplasm and usually occur in latge synovial joints, including the knee, hip and ankle. There are some reports stating that pigmented villonodular synovitis has coexisted with synovial chondromatosis. but none have reported that they occurred simultaneously in a large single joint. This is a report on a diagnosed and arthroscopicully treated pigmented villonodular synovitis and synovial chondromatosis that occurred simultaneously in the same ankle joint.

The Histology and Biomechanical Study of the Effect of Hydroxyapatite Impregnated Bone Cement Implanted in Rabbit Femur / 대한정형외과학회잡지

Hydroxyapatite particle(HA) impregnated polymethylmethacrylate(PMMA) bone cement was fabricated in order to induce bony tissue ingrowth into the pores left behind by the resorption of the HA. The amount of HA was 0, 10, and 30% by weight. After mixing the HA with bone cement it was cast in a 4mm inside diameter glass under(10mm long). Each specimen was cut into half and used for in vitro and in vivo experiment. Diametral and compressive mechanical test were made to evaluate it's mechanical properties. SEM(scanning electron microscope) and ESCA(electron spectroscopy for chemical analysis) were used to evaluate the surface characteristics of the specimen. Push-out test and histologic studies were made after implanting the specimens for 6 weeks in the distal portion of rabbit femur. The mechanical test results show that the average flexural and diametral strength decreased linearly with the increased amount of HA significant(p 0.05) difference between nondecalcified and decalcified specimens in each 10% and 30%, although the latter showed higher interfacial shear strength. Histologic observation showed little evidence of bone ingrowth into HA, but not remarkable. In conclusion, this study could not confirm the earlier results of the bone particle impregnated bone cement without surface grinding since the HA particles were not exposed at the surface by casting it into a glass tube.

Repair and Kennedy LAD Augmentation to Posterior Cruciate Ligament Injury / 대한정형외과학회잡지

The significance of the posterior cruciate ligament (PCL) in the stability of the knee and the necessity for surgical repair of its tears are still controversial. The purpose of this study is to present the short term results of surgical repair and Kennedy LAD augmentation for 15 cases with PCL injury. In 14 patients (15 knees), the torn PCL was repaired with pullout suture technique and Kennedy LAD augmentation was done from june 1993 to june 1994. The follow-up period ranged from 12 months to 25 months (average, 18months). The main causes of injuries were traffic accidents in 12. Thirteen of the patients were men and one was a woman, ranging in age from 17 to 52 years(average, 35 years). 10 knees were acute injury and repaired at average 9 days after injury. There were 11 cases that had combined injuries(4 ACL injuries, 4 meniscus injuries, 3 MCL injuries etc). In eight knees, the tear was in mid substance area and in five it was near femoral attach site and in two it was near tibial attach site. Postoperative results were evaluated by roentgenographic evaluation of posterior sagging and Lysholm knee score. 11 knee were stable but 4 knees were unstable posteriorly during postoperative follow-up period. 3 chronic injuried knees were included in 4 posteriorly unstable knees. There are 7 combined knee injuries in 11 stable knees and no combined injuries in unstable knees and average Lysholm knee score was 89.7 in stable knees and 90 in unstable knees and there was no significant difference between two groups. On the based of this study, surgical repair with pollout suture technique and augmentation with Kennedy LAD in acute PCL injury is a one of the good method for preventing posterior sagging but more longer follow-up period and more cases must be needed to accept this method.