The medial cortical ratio as a risk factor for failure after surgical fixation of proximal humerus fractures in elderly patients.

OBJECTIVES: This study aims to investigate whether the medial cortical ratio (MCR) is associated with fixation failure in patients undergoing plate-screw fixation due to proximal humeral fracture. PATIENTS AND METHODS: Between May 2011 and October 2020, a total of 93 patients (25 males, 68 females; mean age: 74.2±5.3 years; range, 65 to 92 years) who were operated for a proximal humeral fracture were retrospectively analyzed. The patients were divided into two groups during follow-up: patients with fixation failure (n=18) and patients with intact fixation (n=75). After radiological analysis, the MCR and fracture type were recorded. The effects of MCR and fracture type on the development of failure were evaluated. RESULTS: The mean follow-up was 41.3±4.7 (range, 18 to 66) months. There was no significant correlation between fixation failure and MCR in either group (p=0.535). However, the risk of fixation failure increased by seven-fold in patients with MCR greater than 0.09 compared to the other patients. In addition, the fracture type was significantly more severe in the failed fixation group than the intact fixation group (p<0.001). CONCLUSION: Surgical treatment of proximal humeral fractures in elderly patients still remains a challenge for surgeons due to the high failure rate. In elderly patients scheduled for surgery to treat a proximal humerus fracture, a reverse shoulder arthroplasty may be a reasonable choice to avoid reoperation due to fixation failure in elderly with three-part or more fragmented fractures and high MCR.

Does an infra pectineal plate alone provide adequate fixation in anterior column posterior hemitransverse acetabular fractures? A comparative biomechanical study.

BACKGROUND: The purpose of this study is to compare biomechanical properties of suprapectineal (SP) plate fixation, in-frapectineal (IP) plate fixation, and both SP and IP plate fixation in anterior column posterior hemitransverse (ACPHT) fractures of the acetabulum using posterior and anterior column screws. METHODS: In 21 hard plastic left hemipelvis models, ACPHT fractures of the acetabulum were created, and in three different fixa-tion groups, the methods were compared: Group 1: SP plating using a 3.5 mm reconstruction plate and cortical screw fixation, Group 2: Infrapectineal plating using 3.5 mm reconstruction plate and cortical screws combined with posterior and anterior column screws, and Group 3: Combined fixation with SP and IP plating using 3.5 mm reconstruction plates and cortical screws. Maximum load to failure (strength) of these three groups was compared between groups. RESULTS: The mean maximum load of failure for three groups was 2921 N, 2018 N, and 3658 N, respectively. When strength was compared considering the force that causing implant failure, it was determined that the strongest fixation was achieved when SP and IP fixation method were applied together, followed by SP only fixation and IP fixation supported by anterior and posterior column screws, respectively. CONCLUSION: The combined application of SP and IP fixation provides the most stable fixation of the ACPHT acetabular frac-tures, and IP fixation does not provide comparable biomechanical stability despite reinforcement with three-column screws placed away from the plate. Although IP fixation supported by anterior and posterior column screws with the limited combined approach is less invasive approach for patients, SP fixation should be included in the surgical treatment method to ensure adequate stability.

Biomechanical Comparison of Polymethylmethacrylate Augmentation Methods in Failed Pedicle Screw Revision.

AIM: To compare biomechanical results between different polymethylmethacrylate (PMMA) augmentation methods on failed lumbar pedicle screw models of animal vertebrae. MATERIAL AND METHODS: Thirty lumbar vertebrae were harvested from six calves, and their bone mineral density was measured. 60 Polyaxial pedicle screws were inserted to all vertebrae. Pull-out tests were performed to all specimens on an Instron machine. The specimens were randomly divided into four groups. The same screws used in primary screwing process were labeled and used in revision. Screws in the first group were augmented by injecting PMMA into the failed screw hole with a syringe; screws in the second group by inserting bone graft and roll-shaped PMMA, screws in the third group by inserting bone graft and injecting PMMA with a syringe; and the fourth group by inserting bone graft and injecting PMMA through a fenestrated pedicle screw. The pull-out strength (POS) results of all specimens were recorded and compared with statistical analyses. RESULTS: The mean BMD of the vertebrae was 1.31 ± 0.225 g/cm < sup > 2 < /sup > and no significant difference was found between the groups (p > 0.05). The mean POS of the primary screws in the first, second, third, and fourth groups were 2166,5 N/m < sup > 2 < /sup > , 2183,5 N/m2, 2508,5 N/m < sup > 2 < /sup > , and 2005c N/m < sup > 2 < /sup > respectively. After the augmentation, the mean POS in the first, second, third and fourth groups were 3839 N/m < sup > 2 < /sup > , 2874 N/m < sup > 2 < /sup > , 2929 N/m < sup > 2 < /sup > and 3826 N/m < sup > 2 < /sup > respectively. No statistical difference was found between the groups in post-revision POS values (p > 0.05). CONCLUSION: There was no significant statistical difference found in POS between the augmentation methods.

Treatment of Full-Thickness Cartilage Defects with Pedunculated and Free Synovial Grafts: A Comparative Study in an Animal Model.

AIMS AND OBJECTIVES: The purpose of this study was to compare the potential effects of pedunculated and free synovial grafts in the repair of full-thickness articular cartilage defects on an animal model with histological and immunohistochemical analysis. MATERIALS AND METHODS: A comparative study in an animal model was performed with 24 rabbits, divided into two groups. Full-thickness cartilage defects were created bilaterally on the knees of all rabbits. Pedunculated and free synovial grafts were applied to the right knees of Group 1 and Group 2, respectively. Left knees were left as the control group. Six rabbits from each group were randomly selected for euthanasia 4 and 8 weeks postoperatively. All samples were examined histologically with a cartilage scoring system. For immunohistochemical analysis, the degree of collagen 2 staining was determined using a staging system. All data were statistically compared between the study groups with Student's t-test or Mann-Whitney U-test. The correlations between categorical variables were analyzed with Fisher's exact test and Chi-square test. RESULTS: In Group 1, the mean defect size had significantly decreased at 8 weeks postsurgery. It was also significantly smaller than that of Group 2. Both pedunculated and free synovial grafts had significantly better histological and immunohistochemical outcomes compared with the controls. Contrastingly, the results of comparison between the study groups (Group 1 vs. 2) at the 4th and 8th week were not statistically significant with regard to histological scores and immunohistochemical staining. CONCLUSION: Synovial tissue, whether pedunculated or free, provided much better cartilage recovery compared with the control. It can be used as a mesenchymal stem cell (MSC) source, and synovium-derived MSCs have the chondrogenic potential for the in vivo treatment of full-thickness cartilage defects.

Outcomes for core decompression with multiple drilling of the osteonecrosis of the femoral head in patients with solid organ transplantation.

OBJECTIVES: This study aims to investigate the clinical and radiological outcomes of core decompression surgery performed with multiple drilling in solid organ transplantation patients with osteonecrosis of femoral head (ONFH) and evaluate the effectiveness of this procedure in regard to duration of corticosteroid use and stage of osteonecrosis. PATIENTS AND METHODS: A total of 22 solid organ transplantation (kidney, liver or heart) patients (14 males, 8 females; mean age 43.3 years; range, 23 to 67 years) who were scheduled to undergo core decompression surgery with multiple drilling for ONFH were evaluated. Patients' Harris hip scores (HHSs) and radiographic data including Association Research Circulation Osseous (ARCO) staging and Kerboul grading were retrospectively reviewed at pre- and postoperative controls. RESULTS: Patients were followed-up for mean 34.3 months (range, 12 to 76 months). Two patients (9.09%) were performed total hip arthroplasty. These two patients' Kerboul grade was 3. There was no statistically significant relationship between preoperation and postoperative final control in terms of ARCO staging. There was no statistically significant difference between pre- and postoperative HHSs. CONCLUSION: Although multiple drilling is a safe and minimally invasive surgery, its effect is limited, particularly in solid organ transplantation patients with ONFH due to long-term corticosteroid use. Therefore, solid organ transplantation patients should be closely monitored in terms of ONFH development.