Biomechanical Comparison of Headless Compression Screws, Kirschner Wires and Bioabsorbable Pins in Distal Oblique Metatarsal Osteotomy for Correction of Hallux Valgus.

BACKGROUND: Distal osteotomy of the first metatarsal is a widely used method for the correction of mild-to-moderate hallux valgus deformities. The objective of this study was to compare the stability of headless compression screws, kirschner wires and absorbable pins in terms of stiffness and maximum load in distal oblique metatarsal osteotomy. METHODS: A total of 30 4th generation first metatarsal synthetic bone models were divided into three groups according to the fixation techniques. The stiffness of the first metatarsal was calculated as the slope of the linear curve that fit with the first linear part of the force displacement curve. The failure strength was recorded as the maximum load. The stiffness and maximum load values in the axillary and transverse configurations were compared between the three fixation groups. RESULTS: The stiffness was statistically higher in Group K and Group C compared to Group B in both axial and transverse loading. Similarly, the maximum load was significantly higher in both Group K and Group C compared to Group B in both loading conditions. No significant difference was found between Group K and Group C in stability. The higher failure strength was obtained with headless compression screws (113.34±35.88 N) in the axial loading. The lowest failure strength was found in the absorbable pins technique (16.17±7.72 N) in the transverse loading. CONCLUSION: No significant difference was found between the Kirschner wires and headless compression screws techniques, although the highest strength was obtained with headless compression screws that are increasingly used in orthopedic practice.

Minimally invasive osteosynthesis of adult tibia fractures by means of rigid fixation with anatomic locked plates.

Main principle of biological fixation by minimally invasive locked plate osteosynthesis (MILPO) in lower extremity long bone fractures is relative stability which is provided by using long plate with limited number of screws. Some biomechanical studies have been reported about this issue. However, clinical studies are still missing. The aims of this retrospective extended case series were to evaluate the clinical and radiological results of adult tibia fractures treated by MILPO and the effect of plate length and screw density on complication rates. Twenty tibia fractures in 19 patients (mean age 42.3 years) operated by MILPO were reviewed. According to the AO classification, diaphyseal and metaphyseal fractures without intraarticular extensions were simple and wedge-type fractures, whereas all intraarticular fractures were comminuted. Number of screws, cortices and empty screw holes proximal and distal to the fracture, plate-span ratio (plate length divided by overall fracture length), plate-screw density (number of inserted screws divided by number of plate holes), fixation failures, delayed or nonunion, malalignment and leg length discrepancy were documented. Mean follow-up was 16 (range 12-26) months. On average, 4 screws with 6 cortices were used both proximally and distally in all fractures. Only in diaphyseal fractures, one screw hole close to the fracture was omitted. Average plate-screw density and plate-span ratio were 0.68 and 4, respectively. Mean union time was 3 months. There were no cases of delayed or nonunion on the final follow-up. Plate bending was observed in one patient who had fair result. The remaining 18 (94.8 %) patients showed good and excellent results. Satisfactory results can be achieved despite low plate-span ratio and high plate-screw density in simple and wedge-type diaphyseal fractures of the tibia. Additionally, plate-screw density can be higher at metaphysis in intraarticular fractures, in which essential point is a perfectly stable fixation that provides early motion.

Can bone quality be predicted accurately by Singh index in patients with rheumatoid arthritis?

The aim of this study was to evaluate Singh index as a simple and inexpensive means of estimation of bone quality in patients with rheumatoid arthritis. Singh index evaluation was made on digital pelvis radiographs in 50 consecutive patients by three observers. Bone mineral density T scores of the spine and left proximal femur were assessed using dual energy X-ray absorptiometry. Singh index was correlated with densitometry measurements after grouping the patients as normal, osteopenia and osteoporosis. Intra- and interobserver agreements were evaluated by kappa correlations. Sensitivity, specificity, positive and negative predictive values and likelihood ratio's of Singh index were calculated. Both intra- and interobserver agreements were 0.71 (range, 0.69 to 0.72) on average. Singh index proved highly sensitive for the diagnosis of osteopenia at the proximal femur (91%) and spine (90%), whereas the specificity of Singh index for identifying of osteoporosis at the femoral neck (93%) and spine (91%) was higher than sensitivity. Predictive values for osteoporosis at the proximal femur and spine were acceptable and positive likelihood ratios of Singh index for osteopenia and osteoporosis at the proximal femur were 2.4 and 10.1, respectively. Singh index can identify osteoporosis with a high specificity in patients with rheumatoid arthritis. However, the patients who are graded as osteopenia by the Singh index should undergo further evaluation with dual energy X-ray absorptiometry.

Allogeneic blood transfusion decreases with postoperative autotransfusion in hip and knee arthroplasty.

OBJECTIVES: We aimed to evaluate the effectiveness of postoperative autotransfusion method on prevention of the need of allogeneic blood transfusion in hip and knee arthroplasty. METHODS: Seventy-four patients who underwent 77 hip and knee arthroplasty operations were randomized into control and study groups, and evaluated prospectively. In the knee group (39 patients; 30 females, 9 males; mean age 66.6 years), cemented, cruciate retaining, and bicompartmental arthroplasty was performed under tourniquet control; whereas in the hip group (35 patients; 24 females, 11 males; mean age 59.3 years) cementless arthroplasty with posterolateral approach was performed. None of the patients received preoperative and intraoperative allogeneic blood transfusion. The collected blood in the surgical area was transfused with autotransfusion system to the patients in the study groups at the end of the fourth hour postoperatively. The mean amounts of autotransfused blood in hip and knee groups were 413 mL and 480 mL, respectively. Allogeneic blood transfusion was applied to the patients with hemoglobin level below 8 g/dL, hematocrit level below 25%, and clinical symptoms of anemia. RESULTS: Preoperative and postoperative hemoglobin-hematocrit levels did not differ significantly between study and control groups. Allogeneic blood transfusion was applied to one patient (5%) in study and 8 patients (38%) in control groups during knee arthroplasty (p=0.01); whereas 9 patients (53%) in study and 15 patients (79%) in control groups received allogeneic blood transfusion during hip arthroplasty (p=0.044). The amount of allogeneic blood transfusion in study groups was significantly lower than that in control groups (p=0.008 for knee arthroplasty, p=0.048 for hip arthroplasty). CONCLUSION: The need and amount of allogeneic transfusion were reduced with postoperative autotransfusion in both knee and hip arthroplasty groups with greater extent in knee arthroplasty.