Comparison of different fixation methods of bicolumnar acetabular fractures.

OBJECTIVES: This study aims to investigate if the stabilization of iliac wing fractures influences the stability of the acetabular osteosynthesis, if surgical fixation is the choice of treatment, and which technique to be used. MATERIALS AND METHODS: In the study, measurements were performed with an improved finite element model. Tension and displacement values were measured in bicolumnar acetabular fractures in the following cases: combination of cranial and medial plate fixation through the linea terminalis, or combination of cranial plate and quadrilateral surface plates. The iliac wing fracture was either not fixed, or fixed with screws or with a plate. RESULTS: In cases where osteosynthesis was performed through the linea terminalis, 0.01 mm fracture gap displacement was observed with the use of a combination of cranial and quadrilateral surface plate fixations. In the combination of cranial and medial positioned plates, the displacement in the fracture gap was 0.088 mm. The fixation of the iliac wing fracture did not improve the stability of the osteosynthesis of the linea terminalis. Plate fixation of the iliac wing fracture was more stable than screw fixation alone. CONCLUSION: In double column fractures, if the reduction does not require an anterior approach, it is not necessary to fix the iliac wing fracture only to improve the stability of the fixation. If the reduction does require an anterior approach, it is worth fixing the iliac wing fracture with the technically less demanding screw fixation.

Intrapelvic acetabulum surgery: does the positioning of the plate fixation play a role in the stability of the osteosynthesis?

OBJECTIVES: This study aims to investigate whether positioning of the plate fixation plays a role in the stability of the osteosynthesis. MATERIALS AND METHODS: We used finite element modelling to model an anterior pillar fracture and a T-type fracture of the acetabulum. Fracture fixation was carried out in three different variations: cranially positioned plate, medially positioned plate, and a combination of the two methods. In all cases, 3-3 screws were inserted on both ends of the plate to fix the fracture. RESULTS: In both fractures, nearly the same amount of displacement was detected in the fracture gap using a cranially positioned or medially positioned plate, and the amount of displacement was not less when using both plates simultaneously. CONCLUSION: The position of the plate fixation does not affect the stability of the osteosynthesis and in cases of simple fracture patterns, fixation using two plates does not provide more stability than one plate alone.

Does surgically fixation of pubic fracture increase the stability of the operated posterior pelvis?

OBJECTIVES: This study aims to investigate whether surgical treatment of pubic rami fractures increases the stability of the posterior pelvis. PATIENTS AND METHODS: A finite element pelvic model with improved geometric and material characteristics was analyzed. By imitating a standing position, a type I Denis sacrum fracture and a unilateral pubis fracture, we measured the differences in tension and displacement. The posterior injury was treated with a direct plate synthesis or transsacral plate synthesis, while the pubis fracture was left without fixation or fixed with either a retrograde pubic screw or plate synthesis. RESULTS: The operative fixation of pubic rami fractures decreased the movement in the fracture gap not only at the site of the pubis fracture, but also at the site of the fixed sacrum fracture. The plate synthesis provided greater stability of the anterior fracture than the retrograde screw. The tensions in the implants were below the allowed values. CONCLUSION: We concluded that surgically fixation of pubic fracture increases the stability of the operated posterior pelvis.

Further development of our finite element pelvic model to compare fixation methods for pelvic fractures.

OBJECTIVES: In this study, we aimed to create a realistic model which is suitable for computerized simulation of any kind of fractures and provides reliable results. PATIENTS AND METHODS: We used a plastic pelvic model to construct advanced specimens. The data were retrieved from the computed tomography scans of a healthy pelvis. A geometrically exact model by the means of three-dimensional scanning of the plastic pelvis was obtained. The material properties of the bony parts based on the data retrieved from the computed tomography scans were modified. The pelvis was divided into distinct segments and the proportion of the cortical and cancellous bone substance in each segment were determined to make the material properties accurate. In the validation of the pelvic model, a type C pelvic injury was simulated and the fracture of the sacrum and the symphyseolysis were stabilized with plates. These data were compared with those of previously performed cadaver experiments. RESULTS: Based on the simulation performed on the new model, the shift values between the fragments of the broken sacrum approximated the reported values of our cadaver experiments and also arising strains remained in the tolerable interval. CONCLUSION: Our new finite element pelvic model represents the pelvis more accurately than the former one. As the validation of the model was successful, it is suitable for computerized simulation of any kind of fractures offering reliable results.

Functional results and quality of life after shoulder girdle resections in musculoskeletal tumors.

From 1981 to 2001, 91 shoulder resections were performed to treat shoulder girdle tumors (64 primary and 27 metastatic) in 90 patients (53 male and 37 female patients). The mean age was 34 years in patients with a primary tumor and 61 years in those with metastases. There were 7 partial scapulectomies, 13 total scapulectomies, 56 proximal humeral resections, 5 diaphyseal resections, 5 total shoulder girdle resections (Tikhoff-Linberg procedure), and 5 other procedures performed. Prosthesis implantation was carried out in 41 cases, autologous fibular transposition was done in 19, and massive homologous bone grafting was done in 4. Of the patients, 37 were clinically reviewed with a mean follow-up of 4.7 years (range, 1-20 years) by use of the recommendations of the Musculoskeletal Tumor Society for pain, function, position of hand, lifting ability, manual dexterity, and satisfaction. Nine patients were reviewed via a questionnaire and telephone interview. Twenty-six had died, and eighteen were lost to follow-up. The best results were achieved after partial scapulectomy and after humeral resection reconstructed with fibular transposition, when the function of the rotator cuff was preserved. After total scapulectomy and after humeral resection with the implantation of a tumor endoprosthesis, the function of the shoulder remained moderate because the rotator cuff was damaged. The overall satisfaction was generally good after all types of shoulder resections as a result of pain relief, preserved hand function, and improvement of psychological status. Patients can compensate extremely well by using the preserved joints and the contralateral upper limb; therefore, patient satisfaction does not rely on shoulder function alone.

The impact of minimally invasive total hip arthroplasty on the standard procedure.

Minimally invasive total hip arthroplasty using a short skin incision is a subject of much debate in the literature. The present study estimates the possible minimal length of the exposure in an unselected patient cohort and compares the lateral mini-incision technique and traditional total hip arthroplasty (THA). One hundred and two patients were divided into three groups according to the type of surgery and length of incision: mini-incision (less than 10 cm) was performed in 38 patients; midi-incision (10-14 cm) in 43; and standard-incision (longer than 14 cm) in 21 patients. No statistical difference was found with regard to intraoperative and total blood loss, the rate of complications, and postoperative recovery. Significantly decreased body mass index (BMI), shorter operative time, and higher number of hips with malpositioning of the acetabular cup were found in the mini-incision group. These patients, however, experienced less pain in the early postoperative period and were highly satisfied with the cosmetic results. The length of incision was shortened and optimized (less than 14 cm) in 82% of patients, and mini-incision was performed in 38 patients of this unselected cohort. Because of the understandable demand of the patients for less invasive intervention, the surgeon should use a smaller but not necessarily mini-incision with minimal soft tissue trauma that still allows him to perform the procedure well, without compromising the type of implants and the otherwise excellent long-term results. Randomized prospective studies are needed to explore the real value of the minimally invasive total hip arthroplasty.