Open Reduction and Internal Fixation with AO Calcaneal Plate for Displaced Intra-articular Calcaneal Fracture

PURPOSE: To evaluate the surgical outcomes of open reduction and internal fixation of AO calcaneal plate in displaced intra-articular fractures of the calcaneus. MATERIALS AND METHODS: From January 2004 to July 2007, 25 patients with 27 displaced intra-articular calcaneal fractures were treated by open reduction and internal fixation using the AO calcaneal plate. Preoperative, postoperative evaluations and a follow-up after 1 year were done radiologically by the Bohler angle, Gissane angle, heel height and width among all patients. Their functional status was assessed by means of the Maryland foot score. RESULTS: The mean Bohler angle, Gissane angle, heel height and width were restored comparing with preoperative data. However, in Sanders type IV, some losses of reduction occurred at 1 year follow-up (p<0.05). The mean Maryland foot scores were 85 points in type II, 82 points in type III and 63 points in type IV. Sanders types significantly affected the clinical results (p<0.05). CONCLUSION: The AO calcaneal plate fixation using extensile L-shpaed lateral approach shows satisfactory radiologic and clinical results in the treatment of displaced intra-articular calcaneal fractures.

Effect of Hydroxyapatite on Bone Integration in a Rabbit Tibial Defect Model

BACKGROUND: The aim of the present study was to prepare hydroxyapatite (HA) and then characterize its effect on bone integration in a rabbit tibial defect model. The bone formation with different designs of HA was compared and the bony integration of several graft materials was investigated qualitatively by radiologic and histologic study. METHODS: Ten rabbits were included in this study; two holes were drilled bilaterally across the near cortex and the four holes in each rabbit were divided into four treatment groups (HAP, hydroxyapatite powder; HAC, hydroxyapatite cylinder; HA/TCP, hydroxyapatite/tri-calcium phosphate cylinder, and titanium cylinder). The volume of bone ingrowth and the change of bone mineral density were statistically calculated by computed tomography five times for each treatment group at 0, 2, 4, 6, and 8 weeks after grafting. Histologic analysis was performed at 8 weeks after grafting. RESULTS: The HAP group showed the most pronounced effect on the bone ingrowth surface area, which seen at 4, 6, and 8 weeks after graft (p 0.05). On histological examination, the HAP group revealed well-recovered cortical bone, but the bone was irregularly thickened and haphazardly admixed with powder. The HAC group showed similar histological features to those of the HA/TCP group; the cortical surface of the newly developed bone was smooth and the bone matrix on the surface of the cylinder was regularly arranged. CONCLUSIONS: We concluded that both the hydroxyapatite powder and cylinder models investigated in our study may be suitable as a bone substitute in the rabbit tibial defect model, but their characteristic properties are quite different. In contrast to hydroxyapatite powder, which showed better results for the bone ingrowth surface, the hydroxyapatite cylinder showed better results for the sustained morphology.

Risk Factors of Nonunion Demanding Surgical Treatment after Lumbar Posterolateral Fusion

STUDY DESIGN: This is a retrospective study for radiographically and clinically assessing nonunion after lumbar spine fusion. OBJECTIVES: We wanted to analyze the risk factors for nonunion that requires surgical treatment after lumbar spine fusion SUMMARY OF THE LITERATURE REVIEW: A diagnosis of the nonunion after lumbar spine fusion was made by using only the only radiologic images. The incidence of nonunion has been underreported because there are many asymptomatic patients. MATERIALS AND METHODS: The plain X-ray films were evaluated for 1317 patients who could be followed up more than 1 year after lumbar fusion. Nonunion was diagnosed at 1 year after fusion by instability seen on the flexion-extension radiograph and the clinical findings like as sustained pain and local tenderness at the surgical site. The risk factors we reviewed included age, the number of levels fused, associated diseases, smoking, alcohol drinking, the initial diagnosis, a previous history of spinal operation, infection, a clear zone and malposition of pedicle screws and metal failure. The relations between nonunion and the factors mentioned above were analyzed. RESULTS: Thirty-nine patients were diagnosed as having nonunion underwent reoperation and all had surgically confirmed nonunion. Smoking, infection and a previous history of spine operation had a significant influence on nonunion (p < 0.05). Clear zones persisting more than 1 year and metal failure also had a significant influence on nonunion (p < 0.05). Age, the number of fused levels, the initial diagnosis and alcohol drinking were not shown to influence the rate of nonunion (p < 0.05). CONCLUSION: A through clinical and radiologic evaluation is essential to diagnose nonunion, and this should not be done according to the radiologic images only. Risk factors such as a previous history of spine operation, infection, smoking, the development of a clear zone and metal failure all showed a statistically significant influence on nonunion. Additionally, preoperative and postoperative evaluation of these parameters is needed to achieve bone union.

Bipolar Hip Arthroplasty vs. Total Hip Arthroplasty for Osteonecrosis of the Femoral Head / 대한정형외과학회잡지

PURPOSE: To retrospectively compare surgical outcomes between bipolar hip arthroplasty and total hip arthroplasty in patients with osteonecrosis of the femoral head. MATERIALS AND METHODS: Between April 2000 and July 2004, we reviewed 51 cases with Ficat stage III osteonecrosis of the femoral head that underwent bipolar hip arthroplasty (BHA) and 52 cases that received total hip arthroplasty (THA). The minimum follow-up period was 5 years. All prostheses used in the current study had cementless stem and metal-on-polyethylene bearings. We analyzed clinical and radiological results, reoperation, operation time and blood loss the BHA group (mean follow-up of 81 months) and the THA group (82 months). RESULTS: There were no statistically differences between the two groups in preoperative and postoperative mean Harris hip scores. There were no significant differences between the two groups in clinical results, including persistent inguinal pain and radiologic changes around the acetabular cup and femoral stem (p>0.05). Three cases (5.9%) in the BHA group and 5 cases (7.7%) in the THA group underwent revisions. The mean operation time was 96 minutes in the BHA group and 118 minutes in the THA group. Mean blood loss was 625 cc in the BHA group, and 784 cc in the THA group. The differences between the two groups in mean operation time and blood loss were significant (p<0.05). CONCLUSION: The BHA group, which used cementless stem and metal-on-polyethylene bearings for Ficat stage III osteonecrosis of the femoral head, showed no significant differences from the THA group in postoperative radiologic change, clinical evaluation, and reoperation during 81 months of mean follow-up.

Clinical Significance of the Radiolucent Zone Around the Pedicle Screws in the Lumbar Degenerative Disease / 대한척추외과학회지

STUDY DESIGN: A retrospective study. OBJECTIVE: To analyze the clinical significance of the radiolucent zones surrounding pedicle screws. SUMMARY OF LITERATURE REVIEW: Clear zones have been suggested in pseudoarthrosis and a loss of fixation. However, few reports have clearly described the long-term course and clinical significance of clear zones. MATERIALS AND METHODS: The clear zones were evaluated in 399 patients with pedicle screw fixation after 6 months, 1 year, 2 years and 3 years. The patient was considered to be clear zone positive when 1 mm or greater circumferential lucency was confirmed around a screw on film from 2 or more directions. The time-course of the clear zones was examined with regard to age, number of levels fused, bone union, fusion method and reoperation. RESULTS: After 6 months, clear zones were observed in 124 patients (31.1%) but the clear zone-positive rate decreased with time. Clear zones were observed in 89 patients(22.3%), 44 patients(11.0%) and 41 patients(10.3%) after 1 year, 2 years and 3 years, respectively. No new clear zones had developed after 6 months. At the final follow-up, pseudoarthrosis was observed in 12 patients(3.0%). Among them, 11 were clear zone-positive and 1 was clear zone-negative. There was a statistically significant relationship between the clear zone-positive rate and multi-levels, older age and nonunion during following up. In addition, there was a relatively lower clear zone-positive rate in posterolateral fusion combined with posterior lumbar interbody fusion than only posterolateral fusion. However, the difference between them was not statistically significant. CONCLUSION: The presence of clear zones does not always mean pseudoarthrosis but clear zones persisting for more than 2 years after surgery have a higher rate of pseudoarthrosis.

Traumatic Atlanto-Occipital Dislocation: A Case Report / 대한척추외과학회지

Survival after traumatic atlanto-occipital dislocation is rare. Severe persistent neurological deficits are common in the survivors, but early resuscitation and the use of the newer diagnostic techniques have contributed to improved outcomes. We present here the case of a 42 year old man with traumatic atlanto-occipital dislocation combined with a dens fracture, and the patient obtained good clinical results after we applied a Halo-vest and performed posterior fusion.