Predictability of Magerl & McCormack's Load Sharing Classification on the Metal Failure after Pedicle Screw Fixation in the Thoracolumbar Spine Fracture / 대한척추외과학회지

STUDY DESIGN: A retrograde study of metal failures at thoracolumbar spinal fractures fixed using pedicle screws. OBJECTIVES: The predictability and usefulness of the McCormack's classifications for metal failures was compared with Magerl's classifications. SUMMARY OF LITERATURE REVIEW: The load sharing classification was introduced to predict metal failure after short-segmental pedicle screw fixation by McCormack. However, its reliability is uncertain. MATERIALS AND METHODS: From July 2000 to July 2003, this study examined the plain radiographs and CT images of 31 out of 46 patients who underwent posterior stabilization using pedicle screws for thoracolumbar fractures and could be followed up at least 1 year. Fractures were classified utilizing Denis's, Magerl's, and McCormack's systems. RESULTS: As a result of analysis of relation between metal failure and classification system by Magerl or McCormack, there was no significant difference in its distribution. There was no correlation between the fixation range and metal failures in type C3 fractures, but there was a correlation between short fixation and metal failures in rotational burst fractures in short fixation. CONCLUSIONS: In order to prevent metal failures after fixing thoracolumbar spinal fractures by pedicle screws, the stability should be evaluated using Magerl's classification and McCormack's total score. In addition, in cases of type C3 fractures according to the Magerl's classification, reconstructions should be carried out with a long segment fixation or anterior supporting bone grafts, particularly when McCormack's total score is greater than 7.

Effect of Bone Marrow Cell Collection Techniques and Donor Site Locations on In-Vitro Growth of Bone Forming Cells

PURPOSE: This study evaluated the influence of bone marrow cell collection techniques and donor site locations on the in-vitro growth of bone-forming cells. METHODS: Sixty six samples of bone marrow cell collections (BMCC) or bone marrow aspirates (BMA) from 15 patients were obtained. Thirty eight samples for culture were composed of 23 BMA from 7 tibial condyles and 16 ilia, with the other 15 BMCC from the contralateral ilia. The other 28 samples were used for the analysis of alkaline phosphatase activities. After counting total cell number, mesenchymal stem cells (MSC) obtained from samples were incubated for 14 days. Alkaline phosphatase staining was used to count the number of stained colonies to show osteogenic differentiation. RESULTS: The average MSC counts of BMA from tibial condyles and ilia were 1.42x10(6) and 7.35x10(6) respectively, with 4.80x10(6) from ilial BMCC (p=0.010). MSC cultures could not be produced from tibial condyles in all 7 samples. However, 9 of 15 BMCC samples and 9 of 16 ilial BMA samples were successfully cultured (p=0.018). The average of cell counts in the successful cultures was 7.92x10(6), whereas that in the failed cultures was 2.85x10(6) (p=0.000). Multiple regression analysis showed that colony count was associated with the patient's age and total cell numbers, but not with collection methods such as BMCC or BMA (p=0.000, R=0.648, beta; age=-0.405, cell number=0.356). The discriminating formula indicated that more than 5.25x10(6) cells were needed for successful culture. CONCLUSIONS: For successful cultures in vitro and for grafts, the total number of collected bone forming cells is more important than donor sites or collection methods. For young patients, grafting of bone-marrow-derived osteoprogenitor cells is promising.

The Treatment of IM Nailing of Femoral Shaft Fracture: Piriformis Fossa versus Trochanteric Entry Portal

PURPOSE: To compare the results of IM nailing of femur shaft fractures using trochanteric and piriformis fossa entry portal. MATERIALS AND METHODS: 37 patients were treated with IM nail using Trochanteric (Trochanter group: TG, n=17) and piriformis fossa entry portal (piriformis group: PG, n=20) and were followed from February 2004 to 2007. The outcomes were assessed based on the clinical and radiographic findings. RESULTS: The functional result, ROM and union time were similar in both groups. The alignment was similar in both groups but PG showed variable alignment in proximal 1/3. Incision was larger in PG (PG=8.7 cm, TG=5.8 cm, p0.05), there was statistically significant difference in overweight groups (PG=125 minutes, TG=90 minutes, p<0.05). Blood loss was 313 cc in PG, 268 cc in TG and less in TG in overweight patients (p<0.05). There was 5.7degrees of varus angulation in PG, 2 nonunion cases in both groups. CONCLUSION: The femoral nail specially designed for trochanteric insertion resulted in high union rates, low complication rates similar to conventional nail and the trochanteric nail can be the alternative choice especially in proximal femur fracture and overweight patients.

Results of Surgical Treatment in Combined PCL and PL Instability of the Knee / 대한정형외과학회잡지

PURPOSE: To evaluate the functional results, activity status after surgical treatment in combined PCL and PL instability of the knee. MATERIALS AND METHODS: Fifteen patients with combined PCL and PL injury were diagnosed and treated. PCL injury was treated by using tibial inlay method with arthroscopy and PL injury was treated by using repair (acute 4 cases) and reconstruction (chronic 11 cases, Warren method) and followed more than 2 years with average follow-up period of 27.3 months (24-38). Mean age was 39 years (17-67) at operation. Radiologic evaluation was done by simple X-ray, stress view and MRI. Functional evaluation of Lysholm score and Tegner activity score was used. RESULTS: Average Lysholm and Tegner activity score was 43 and 1.5 preoperatively and was improved to 85 and 4.0 postoperatively. Varus laxity was improved from 9.3 mm to 4.0 mm and posterior translation was improved from 18.4 mm to 5.6 mm in stress view. The PCL and PL instability of the knee were improved in all cases. Postoperative improvement of functional and activity score were determined by absence of combined injury not by age or delayed time for operation. Complications were limitation of motion (3 cases), lateral instability (4 cases), osteoarthritic change (4 cases) and quadriceps atrophy (15 cases, severe 4 cases). CONCLUSION: PCL reconstruction using tibial inlay method and PL reconstruction using warren method (chronic cases) and repair (acute cases) improved function, activity and stability in PCL and posterolateral instability.