Results of Non-fusion Method in Thoracolumbar and Lumbar Spinal Fractures / 대한척추외과학회지

STUDY DESIGN: A retrospective study of surgically managed patients. OBJECTIVES: To evaluate the results of posterior stabilization of a thoracolumbar fracture, without fusion, followed by the removal of metal implants within an appropriate period. Changes in the sagittal alignment and the restoration of segmental motion were also investigated. SUMMARY OF LITERATURE REVIEW: In managing unstable thoracolumbar and lumbar fractures, posterior fusion, using a transpedicular screw system, has been the treatment of choice, but results in the permanent loss of segmental motion. MATERIALS AND METHODS: Twelve patients with thoracolumbar and lumbar spine fractures, under 40 years of age (mean 28.4 years), were managed using this non-fusion method. Implants were removed at mean 9.2 months after the initial fixation of the fracture. For metal-fixed segments, the sagittal alignment, such as the angle of kyphosis, height of body, recovered motion range in flexion-extension and right-left bending view, were measured radiologically and compared with a control group. Clinical aspects, such as gross deformity and functional ability, were also investigated. RESULTS: The average sagittal angle at the time of injury was average 17.2 degrees, but became 1.7 degrees post-fixation, which increased after removal of the implants, reaching 9.8 degrees at the final follow up. The height of the fractured body was maintained until the final follow-up. The mean segmental motion measured in the sagittal and coronal planes were 11.7 and 9.5 degrees, respectively. Most patients were satisfied with the final gross appearance and functional outcomes. Only one patient showed considerable development of kyphotic angulation, but the functional outcome was good. CONCLUSION: The author's non-fusion method seems to be effective in achieving stability and sagittal alignment, as well as in regaining segmental motion of the fixed segments. The non-fusion method seems to be an effective method for managing thoracolumbar fractures, especially for young active persons.

Bone & Soft Tissue Injuries Diagnosed by Magnetic Resonance Imaging in Thoracolumbar Fractures

PURPOSE: To assess diagnostic efficacy of the MRI in thoracolumbar fractures, especially in changes of bone and soft tissue which cannot be documented by other diagnostic tools. MATERIALS AND METHODS: Among 85 patients managed for thoracolumbar fractures between January 1997 and June 2003, MRI was performed in 30 patients to get more informations. Plain X-ray, CT and MRI of these cases were reviewed retrospectively by two orthopaedic spine surgeons and one radiologist to investigate the informations which only MRI could afford. RESULTS: 14 (46.7%) among 30 patients had occult fractures of vertebrae other than main fracture which had not been diagnosed as fractured. Besides 6 patients who showed distraction of posterior structure on plain X-ray, injury of posterior ligament complex was confirmed by MRI in 12(40%) patients. Additionally, MRI visualized other soft tissue injuries such as intramuscular and subcutaneous hematoma, changes of the spinal cord and intervertebral disc. In 16 among 30 patients, informations achieved from MRI were the most important factors in deciding treatment modality. CONCLUSION: MRI seems to be efficient in visualizing not only soft tissue injury such as ligament but also occult fractures of additional vertebra in thoracolumbar fractures, therefore MRI seems to be an important diagnostic tool in decision of treatment modalities, especially in cases of uncertain stability.

Distribution and Patterns of Posterior Column Injury in Flexion-Distraction Injuries of Thoracolumbar Spine / 대한척추외과학회지

STUDY DESIGN: A retrospective analysis of the distribution and patterns of posterior column injury in flexion-distraction injuries of the thoracolumbar spine. OBJECTIVES: To recognize the various types of posterior column injury in terms of the path of the distraction force in flexion-dis-traction injuries of the thoracolumbar spine. SUMMARY OF LITERATURE REVIEW: As posterior column injuries are associated with instability of the spine, many authors have described and classified posterior column injuries. However, there are no descriptions or classifications in terms of the path of the distraction force in the literature. MATERIALS AND METHOD: The preoperative plain X-rays, axial CT, MRI (in 5 patients) and operation records of 34 patients were reviewed in relation to the patterns of posterior column injury. RESULTS: Posterior column injuries can be classified into two main types. In Type I(30/34), the distraction failure started from the spinous process one level above the fractured body (Type IA) or the posterior ligament complex between the spinous processes of the fractured and the level above (Type IB). In Type II(4/34), the distraction failure started from the spinous process of the fractured vertebra and from the interspinous ligament between the fractured level and the level below. CONCLUSIONS: Posterior column injuries can be described according to their starting point and the extent of the distraction force. Of these, Type IB was the most common. Using this classification, the injury of the posterior column in injuries of the thora-columbar spine fracture can be predicted.

Early Decompressive Surgery for Compressive Neuropathy by Hematoma after Posterior Spinal Decompressive Surgery / 대한척추외과학회지

STUDY DESIGN: A retrospective analysis was performed to identify the diagnostic and therapeutic factors related to postoperative compressive neuropathy by hematoma after posterior spinal decompressive surgery. OBJECTIVES: To document by analysis the clinical course of postoperative compressive neuropathy by hematoma, the efficacy of early surgical decompression, and to recommend methods of prevention. SUMMARY OF LITERATURE REVIEW: Various diagnostic and treatment modalities have been applied to postoperative compressive neuropathy after spinal surgery. However, the timing of surgical decompression remains controversial. MATERIALS AND METHODS: Five cases of postoperative compressive neuropathy after posterior spinal decompressive surgery, which occurred from May 1996 to May 2000, were investigated in terms of causes, clinical courses, and management profiles after early surgical decompression, and final outcome. RESULTS: Five cases (2.14%) among 234 patients were managed by re-decompression including the evacuation of hematoma. Four cases, which had been managed by earlier surgical decompression showed neurologic improvement after 2 postoperative weeks, and achieved favorable clinical results without grave neurologic sequelae. However, in one case, in which surgical decompression had been delayed, weakness of the peroneii remained. CONCLUSION: Early evacuation of hematoma achieved a more favorable result than a delayed operation. Early diagnosis and prompt surgical decompression is recommended to reduce neurologic sequelae.

Differential Diagnosis of Heel Pain in Seronegative Spondyloarthropathy from the Heel Pain Syndrome / 대한정형외과학회잡지

PURPOSE: We attempted to differentiate the heel pain in seronegative spondyloarthropathy from that in the posterior heel pain syndrome. MATERIALS AND METHODS: Forty one patients who complained of heel pain were included in this study. The evaluation consisted of history taking, physical examination, roentgenogram, bone scan, and serological tests including ESR, CRP, rheumatoid factor, and HLA-B27. The patients were classified into two groups. Group A consisted of seronegative spondyloarthropathy patients and group B consisted of plantar fasciitis, Achilles tendinitis, and retrocalcaneal bursitis patients. RESULTS: There were 14 patients in group A, and 27 patients in group B. The characteristic clinical features were the following in group A compared with those in group B. The age of patients was younger and males predominated. Also patients complained of a combined metatarsalgia or other joint pain. On the physical examination, tenderness existed on the calcaneal body rather than the bony attachment site of Achilles tendon or plantar fascia. Serologic tests revealed an elevated ESR, and a positive HLA-B27. A bone scan showed diffuse uptake in the calcaneal body and the metatarsophalangeal joint area, and an increased SIS ratio. CONCLUSION: Seronegative spondyloarthropathy should be differentiated in a patient who complains of heel pain.

Management of Deep Infection after Posterior Spinal Instrumentation with Prolonged Suction Drainage / 대한척추외과학회지

STUDY DESIGN: A retrospective analysis about related diagnostic and therapeutic factors in postoperative deep infection cases after posterior spinal instrumentation. OBJECTIVES: Analysis of the inherent risk factors associated with deep infection and the efficacy of management with prolonged suction drainage without removal of implants. SUMMARY OF LITERATURE REVIEW: Various treatment modalities have been applied to control deep infection after spinal instrumentation. Validity of removing implants to control the infection is still controversial because it may cause loss of spinal stability. MATERIALS AND METHODS: Five cases of postoperative deep infection after posterior spinal fixation from May 1996 to May 2000 were investigated about combined general illness, features of infection, various profiles on management of the infection with surgical irrigation and debridement followed by prolonged suction drainage, and final outcomes. RESULTS: Remarkable risk factors were diabetes and obesity. Evidences of infection such as discharge from the wound, dehiscence, fever were observed since average 18.8th day postoperatively. By only one surgical procedure for each patient followed by prolonged suction drainage for mean 19.2 days and administration of IV antibiotics for average 43.6 days followed by oral antibiotics for 33.8 days, deep infections were controlled successfully without removal of implants and without any grave complications. All achieved favorable clinical results and posterolateral fusion. CONCLUSION: Irrigation and debridement accompanied by prolonged suction drainage using Hemo-vac and administration of susceptible antibiotics seemed to be one of the effective methods in controlling deep infection after posterior instrumentation and in maintaining the postoperative stability of spine.

MMPI Profile in Patients with Chronic Low Back Pain / 대한정형외과학회잡지

PURPOSE: The causative pathology of chronic low back pain cannot be defined in many patients. To evaluate the relations between psychoneurotic status and chronic low back pain, the authors surveyed Minnesota Multiphasic Personal Inventory (MMPI) in the patients with chronic low back pain. MATERIALS AND METHODS: From July 1997 to December 1998, questionaire including MMPI were given to the patients who visited our Department for chronic (>6 weeks) low back pain. 50 patients (33 male, 17 female) completed MMPI. The mean age was 33.4 years (range 17-55) . MMPI scores were evaluated in two ways for each individual, mean scores of each clinical scale and two code method. Then mean scores were compared according to sex, radiating pain, radiologic abnormalities. RESULTS: In total 50 patients, three scales showed mean score over 55. Those were Hs:59.1 +/- 10.3, D:55.4 +/- 11.2 and Hy: 59.0 +/- 10.8. No significant differences were observed between the groups divided according to the sex, radiating pain, radiologic abnormalities. The two code method revealed that at least one of the neurotic triad (Hy, Hs, D) ranked within the highest two in 46 (92%) patients. CONCLUSION: It seemed that large proportion of patients with chronic low back pain had psychological tendency to hypochondriasis and/or depression and/or hysteria. MMPI seemed to be one of the useful methods in evaluation of psychogenic factors in chronic low back pain patients without definite organic pathology.

Bridge Reconstruction of Donor Iliac Crest with Resected Rib in Anterior Fusion of Thoracolumbar Spine / 대한척추외과학회지

STUDY DESIGN: A retrospective study about the efficacy of bridge reconstruction of donor iliac defect utilizing resected rib dur-ing surgical approach of thracolumbar vertebrae. OBJECTIVES: To evaluate the outcome in clinical aspect for cosmesis and pain, and radiological aspect for incorporation of rib with crest. SUMMARY OF LITERATURE REVIEW: Many iliac donor site problems were reported such as pain, deformity, fracture etc. Filling the bone defect with bone, cement, or artificial bone seems to reduce the donor site problems. MATERIALS AND METHODS: In fourteen patients who underwent anterior fusion of vertebrae, bridge reconstructions of iliac crest using resected rib for thoracoabdominal approach to vertebral body were performed. Postoperatively, donor site pain, residual deformity, and radiologic finding of the union between rib and iliac crest were evaluated. RESULTS: No patients had significant pain on donor iliac crest. Acceptable pain was complained by five patients after 1 month postoperatively and by three patients after 2 months postoperatively. After 3 months, no patients had pain problem at iliac donor site. Two patients presented palpable step-off on iliac crest, but external contours of iliac crest were satisfactory in all patients. Radi-ologic union of the rib-crest junction was confirmed within 6 months postoperatively in all cases. CONCLUSIONS: Bridge reconstruction of iliac crest defect using resected rib is a simple and effective method that can minimize residual donor site problems in anterior spinal surgeries of thoracic and upper lumbar vertebrae.

Morphological Difference of Polyethylene Section in Knee Arthroplasty

The purpose of this study is to see the value of transsectional morphology of polyethylene for evaluation of wear and characteristics of ultra-high molecular weight polyethylene. Retrieved nineteen polyeth- ylene tibial components were examined for this study. Ten components were the directly molded 1900 Himont polyethylene, and 9 components were the machined GUR 415 polyethylene. Transsection of polyethylene(thickness: 60 - 150 micron) was obtained by microtome and was examined microscopical- ly for the fusion defects, subsurface white bands, and delamination as a mode of wear. Significant differ- ences between two groups of polyethylene were found. Fusion defects greater than 100 micron were observed in 5 among 9 GUR 415 polyethylene. Subsurface white band were observed in 7 among 9 GUR 415 polyethylene. Delamination was found in 6 arnong 9 GUR 415 polyethylene. Neither fusion defects greater than 100 micron, nor delamination were observed in 1900 Himont polyethylene. Morphological examination of polyethylene section is an efficient way to differentiate the polyethylene and to evaluate the wear behavior of retrieved polyethylene. This study suggests that delamination of polyethylene tibial components is influenced by resin type and / or manufacturing method.

Analysis of Tensile Strength of Double Helix Wires / 대한정형외과학회잡지

PURPOSE: To compare the tensile properties of double helical twisting. MATERIALS AND METHODS: 21G and 18G stainless steel wires were used. Monostrand, untwisted double strand and manually twisted double helix wires were tested under gradually increasing tension force until the wires break. Data were analyzed by using a computer system to get force-strain curves. RESULTS: Forces at the break point showed no significant differences between untwisted double strand wires and helically twisted double strand wires. Forces at the yield point deformation were proportionally increased to the degree of helical twisting until the wires were twisted 20 times (piptch number: 24/10 cm) with no more increase after then. Final strain at break point decreased by helical twisting, which means the range of plastic deformation decreased. CONCLUSION: By helical twisting, the wires increase in elastic range and decrease in plastic deformation. Therefore, double helix wiring seemed to be a more effective method of fixation compared to the untwisted double strand wires.

Multifocal Acute Osteomyelitis in a Mole Adolescent: A Case Report / 대한정형외과학회잡지

A 13-year-old boy developed fever and right leg pain, and multiple acupunctures were done on legs, then visited our ER for high fever, chill and painful swellings in both legs. Bone scan showed multiple hot spots on both distal femur, both proximal tibia, and left distal tibia. MRI revealed subperiosteal abscess in right proximal and left distal tibia and signal changes without abscess in other hot spot sites on bone scan. Surgical drainage of subperiosteal abscess and curettage were performed in the right proximal and the left distal tibia. Percutaneous drillings were done to other hot spot sites. All the lesions were cured after combined antibiotic chemotherapy. Multifocal osteomyelitis in a rapidly growing adolescent has been reported not rarely. It seemed that more attentions should be paid to the possibility of multifocal acute osteomyelitis in an adolescent

Efficacy of Bee Venom Injection for Osteoarthritis Patients / 대한류마티스학회지

OBJECTIVES: Bee venom contains a potent antiinflammatory peptide 401 as well as mellitin. The purpose of this study was to see the efficacy and safety of purified bee venom injection therapy for knee or spinal osteoarthritis patients. METHODS: One hundred and one osteoarthritis patients were randomly assigned to bee venom injection therapy or oral nabumetone medication group. Bee venom injection group was subdivided into 3 groups according to different dosing schedule(group A: gradual increase up to 0.7mg, group B: up to 1.5mg and group C: up to 2.0mg). Control group patients(group D) were given 1000mg nabumetone daily for 6 weeks. There were 25, 26, 25, and 26 patients assigned to A, B, C, or D group. The efficacy of treatment was evaluated by measuring instruments developed by authors, and the safety of bee venom injection was evaluated by hematology and chemistry laboratory examination. RESULTS: Among 101 patients, eighty-one patients completed the study, but twenty patients were dropped out and two of these patients were dropped out due to adverse drug reaction. The efficacy in bee venom group showed better improvement than nabumetone group(p<0.01). Within bee venom group, group B and C showed better improvement than group A(p<0.01). Itching around injection site occurred in most patients, and bodyache occurred in 49 patients (81.7%). Hemoglobin was decreased(0.3g/dl) in group C, but no significant changes were observed in other laboratory values. CONCLUSION: The efficacy of bee venom injection in the control of knee or back pain in osteoarthritis patients was better than nabumetone medication. No severe allergic or adverse reaction was observed in bee venom treatment patients, but problems related with bee venom injection, such as pruritis, bodyache, and the possibility of anaphylaxis, should be considered for the use of bee venom injection.

Lumbar Disc Herniation with Cauda Equina Syndrome after Self Traction Therapy: A Case Report / 대한척추외과학회지

STUDY DESIGN: A retrospective case report of lumbar disc herniation with cauda equina syndrome after self traction therapy. OBJECTIVES: Documentation of clinical significance and manifestations of disc herniation with cauda equina syndrome as one of the complications after self traction therapy. SUMMARY OF BACKGROUND DATA: Various conservative managements of acute low back pain in adults such as traction, spine manipulation therapy(SMT), and exercise therapy may produce harmful complications, especially when performed by non-professional therapists. Recently, reports of complication from SMT are increasing, however, understanding of biomechanism and natural history of traction, SMT, and exercise therapy are still poor. Therefore background information on the possible complications from their management is essential for physicians. METHOD: A case of acute cauda equina syndrome after self traction therapy in a 41 year-old man. Magnetic resonance imaging revealed severe compression of cauda equina by a huge mass. Emergency lumbar laminectomy was performed and all the compressing mass was removed. The mass was proven to be prolapsed disc of nearly whole nucleus amount and scanty nucleus was found within the disc space. RESULT: Acute low back pain and radiating pain disappeared immediately after operation. And neurologic deficits began to improve after postoperative 1 week. At the 15 month follow-up, the patient had recovered fully except minimal paresthesia on the right foot. CONCLUSION: More attentions to the possibility and clinical features of this complication seemed to be needed to the clinicians and therapists who do conservative management for the low back problems, especially SMT, traction, exercise therapy etc.

The Significances of Bony Lesions Observed on MRI of Traumatic Knees / 대한정형외과학회잡지

Diagnosis of trauma to the soft tissue structures of the knee such as menisci, cruciate ligaments, and collateral ligaments has been greatly advanced by MRI. Some bony lesions which couldnt be seen by simple X-rays, also became to be visualized by MRI. The authors reviewed 131 MRI s of traumatized knees from March, 1992 to August, 1995. Among them, various traumatic lesions of bone were found in 62 cases. Those cases were thoroughly reviewed to define the significances of the lesions, by reviewing the medical records and careful examination of simple X-rays and MRI. The bony lesions could be classified into four groups, such as coronal plane injuries (valgus, varus), sagittal plane injuries(contusion of proximal tibia-posterior cruciate ligament injury, patello-femoral contusions), nonspecific direct contusion, and tibial condylar fractures. In the valgus group, 3 components of MRI lesions as the evidences of valgus injury could be observed. They were direct contusions on lateral aspect of the knee, tension failure of medial aspect(medial collateral ligament injury), compression failure of lateral aspect of knee(focal compression lesions of femoral and/or tibial condyle adjacent to lateral meniscus). In other types of injuries, similar findings were observed as evidences of the events at the trauma. Most of the bony lesions were located at the sites where external forces were exerted and/or internal responses took place. It seems that bony lesions seen at MRI of traumatized knee are not simply meaningless, incidental findings but document the events at the time of the trauma.

Occlusion of Vertebral Artery and Cerebral Infarction after Cervical Spine Fracture: A Case Report / 대한척추외과학회지

STUDY DESIGN: A case of brain infarction due to occlusion of vertebral artery after cervical spine fracture is reported. OBJECTIVES: Documentation of possibility and clinical significances of brain infarction as one of grave complications after cervical spine injury. SUMMARY OF LITERATURE REVIEW: Occlusion of vertebral artery and consequent brain infarction can be associated with cervical spine injuries because vertebral arteries course through the transverse foramina from sixth to second corvical vertebrae. Infarction of vertebrobasilar system may cause impairment of cerebral, cerebellar, or brain stem function and can occasionally bring grave functional loss, even death. MATERIALS AND METHODS: A case of occlusion of vertebral artery and consequent cerebral infarction after cervical spine fracture in a 66 year-old man. Brain CT and angiogram were performed. He was managed with anticoagulants. RESULTS: Neurologic deficits from brain infarction disappeared after 2 weeks. CONCLUSIONS: Attention to the possibility of these complications and awareness of their clinical features seem to be mandatory in managing cervical spine injury patients.

Total Hip Replacement Arthroplasty in Ankylosing Spondylitis / 대한정형외과학회잡지

Total hip replacement arthroplasties(THRA) have been done in 19 patients(31 hips), who were diagnosed ad ankylosing spondylitis from January, 1984 till July, 1993 at Seoul National University Hospital. All patients were male; 12 patients were affected bilaterally. Modified New York criteria was used as diagnostic criteria. HLA B27 antigen was positive in 18 cases(95%). The thoracolumbar spine and sacroiliac joint were affected in all cases and cervical spine was affected in five patients, among them, fiberoptic laryngoscopic intubation was needed in four cases. The trastrochanteric approach was used in 19 cases, which have severe limitation of motion and deformity of the acetabulum. For the prevention of postoperative heterotopic ossification, low dose radiation therapies were done in 10 cases of the risk group. The average follow-up period was three year and eleven months(two year-seven year and 10 months). Harris hip score and radiographs were obtained at each follow-up. The mean preoperative Harris hip score was 50(19–90), and finally, the mean Harris hip score was 87(68–96). Loosening of endoprothesis was noted in 3 cases and heterotopic ossification in 5 hips. Ischial enthesopathy was observed in 13 cases. Among the hips which had heterotopic ossification, four were class Ι by Brooker's classification and only one was class Ⅲ. No nonunion was observed in the cases which had trochanteric osteotomy expect breakage of wire in 4 cases. In THRA of ankylosing spendylitis, we obtained good result clinically and radiologically. In severely affected cases, we had used transtrochanteric approach and obtained good result due to better operative field. The incidence of heterotopic ossification was not significant and the prophylactic low dose radiation therapy seems to be effective in risk group.

Developmental Coxa Vara / 대한정형외과학회잡지

Deveolopmental coax vara represents coax vara not present at birth but rather developing in early childhood, showing a progressive deterioration in the proximal femoral neck-shaft angle during growth. In order to determine the factors that could affect the results of corrective osteotomy, we evaluated the results of 15 developmental coax vara in 12 patients who had been treated with the femoral osteotomy at the Department of Pediatric Orthopedic Surgery, Seoul National University Children's Hospital, from February 1983 to March 1993. Of the 12 patients, there were 6 boys and 6 girls. Three patients had bilateral operations, 5 patients on the right, and the remaining 4 patients on the left. Average at the onset of symptoms was 4 years plus 5 months(range; from 1 year to 7 years plus 2 months), and average age at the tome of operation was 6 years plus 3 months(range; from 2 years plus 4 months to 10 years). We could obtain the following results: 1. Average post-operative loss of neck-shaft angle was 5% in the cases in which post-operative neck-shaft angle was converted more than 130 degrees, and was 8% in the cases in which post-operative neck-shaft angle was converted less than 130 degrees. 2. Loss of neck-shaft angle was higher during the first post-operative period, and was higher in cases in which the triangular osseous defect was persistent post-operatively. There was no correlation between the post-operative neck-shaft angle and disappearance of triangular osseous defect. 3. The femoral anteversion was converted 8.7 degrees to 27.2 postoperatively. 4. The premature arrest of the capital femoral physis was higher in cases in which the neck-shaft angle was less than 130 degrees postoperatively. 5. Leg length discrepancy, which was 2.1 cm preoperatively, did not change in cases in which the neck-shaft angle was more than 130 degrees postoperatively. However, it was converted to 3.3 cm in cases in which the neck-shaft angle was less than 130 postoperatively. 6. we could observe the femoral head deformity in 6 out of 7 cases in which the operation was performed after 7 years of age. We could draw the following conclusion based on our results: 1. We must correct the neck-shaft angle more than 130 degrees. 2. We could not equalize the leg length discrepancy by corrective osteotomy alone. 3. It may be reasonable to perform the corrective osteotomy before 7 years of age.

Radiological , Biomechanical and Histological Analysis on the Surgical Treatment of Bone Defect in Rabbit Tibia using Glass Ceramics / 대한정형외과학회잡지

To investigate in vivo reaction of newly developed glass ceramics, five milimeters of one proximal tibia of the rabbits were resected and the defect was replaced by ready-made glass ceramics cylinder of 5mm height. As a control, the other intact tibia was used in biomechanical study. Radiological examination was performed every 2 weeks postoperatively. Histological and electromicroscopic examinations were performed postoperatively at 2nd, 4th, 8th and 16th weeks. And fourpoint bending study was performed postoperatively at 8th and 16th week. Following findings were observed : On radiological examination, radiolucent line was seen around glass ceramic at 2-week X-ray. This line was obliterated gradually until 6-week X-ray. Remodelling of medullary cavity was noted from 6-week or 8-week X-ray, and was almost completed at 12-week X-ray. The glass ceramic was innocently incorporated into the host bone. On biomechanical examination, 8-week specimen was broken at 33% of break strength of control group and 16-week specimen was broken at 62%. On histological examination, in 2-weeks specimen, part of implanted glass ceramics was covered with new bone; in 4 weeks, implanted glass ceramics was surrounded by new bone and the surface was tightly bound to the new bone; in 8-week specimen, mature lamellated bone was showed and amount-of bone was increased. Based upon above findings, it was suggested that the glass ceramics was innocently incorporated into the host bone and revealed good biomechanical strength.