Effects of hexagonal boron nitride on mechanical properties of bone cement (Polymethylmethacrylate).

OBJECTIVES: The aim of this study was to investigate the effects of adding hexagonal boron nitride at four different concentrations to polymethylmethacrylate (PMMA) bone cement, which is commonly used in orthopedic surgeries, on the mechanical properties and microarchitecture of the bone cement. MATERIALS AND METHODS: The study included an unaltered control group and groups containing four different concentrations (40 g of bone cement with 0.5 g, 1 g, 1.5 g, 2 g) of hexagonal boron nitride. The samples used for mechanical tests were prepared at 20±2ºC in operating room conditions, using molds in accordance with the test standards. As a result of the tests, the pressure values at which the samples deformed were determined from the load-deformation graphs, and the megapascal (MPa) values at which the samples exhibited strength were calculated. RESULTS: The samples with 0.5 g boron added to the bone cement had significantly increased mechanical strength, particularly in the compression test. In the group where 2 g boron was added, it was noted that, compared to the other groups, the strength pressure decreased and the porosity increased. The porosity did not change particularly in the group where 0.5 g boron was added. CONCLUSION: Our study results demonstrate that adding hexagonal boron nitride (HBN) to bone cement at a low concentration (0.5 g / 40 g PPMA) significantly increases the mechanical strength in terms of MPa (compression forces) without adversely affecting porosity. However, the incorporation of HBN at higher concentrations increases porosity, thereby compromising the biomechanical properties of the bone cement, as evidenced by the negative impact on compression and four-point bending tests. Boron-based products have gained increased utilization in the medical field, and HBN is emerging as a promising chemical compound, steadily growing in significance.

Using Proximal Hooks as a Soft-Landing Strategy to Prevent Proximal Junctional Kyphosis in the Surgical Treatment of Scheuermann's Kyphosis.

AIM: To evaluate the occurrence of proximal junctional kyphosis (PJK) as well as both the clinical and radiologic outcomes of patients who underwent surgery for Scheuermann?s Kyphosis (SK) using either exclusively pedicle screws or a combination of proximal hooks and pedicle screws constructs. MATERIAL AND METHODS: Surgically treated 37 patients with the diagnosis of SK were evaluated retrospectively. The patients were divided into two groups based on the type of instrumentation employed. The first group contained 22 patients with only pedicle screws (PP) while the second group consisted of 15 patients with mixed constructs that were proximal hooks and pedicle screws (HP) at the rest of the levels. The clinical and radiological data were compared in patients who were followed up for a minimum of 2 years. RESULTS: The average duration of follow-up for the PP group was approximately 94.7 ± 53.1 months, whereas the HP group had an average follow-up period of around 103 ± 64.4 months. After conducting the analyses, no statistically significant findings were identified in the measurements taken for the SRS-22 scores in preoperative, postoperative, and the most recent follow-up radiographs (p > 0.05). It is worth noting that among patients who exclusively utilized pedicle screws, both the proximal (p=0.045) and distal (p=0.030) junctional kyphosis angles experienced more pronounced increases compared to hybrid structures. CONCLUSION: While no notable distinction was observed between the two groups, patients with pedicle screws fixation had a higher PJK angle. Conversely, the use of hooks at the upper end seems to be a preventive measure against the development of PJK.

Cakirgil method in the surgical treatment of older children with developmental dysplasia of the hip: Mid-term follow-up results of 17 hips and literature review.

OBJECTIVES: This study aimed to evaluate the results of the Cakirgil method in patients with advanced developmental dysplasia of the hip (DDH). PATIENTS AND METHODS: Patients who underwent surgical treatment with the Cakirgil method between January 2011 and December 2022 with a diagnosis of DDH were retrospectively scanned. Thirteen patients (7 females, 6 males; 8.0±2.7 years; range, 5 to 12 years) with severe DDH were included in the study. The results of the Cakirgil method, including adductor tenotomy, open reduction, femoral shortening, varus and derotation osteotomy, and Dega acetabuloplasty, were retrospectively evaluated in 17 hips of these 13 patients. Clinical and radiological evaluation was performed according to the acetabular index, center edge angle, Severin score, and McKay criteria. RESULTS: Five patients had comorbidities. The mean follow-up period was 78.3±28.9 (range, 12 to 135) months. The acetabular index decreased from 35.24° to 22.06° and center edge angle improved from -34.71° to 26.59°. The Severin score decreased from 4.82 to 2.29 and the McKay criteria from 3.47 to 1.88. All changes were statistically significant (p<0.001). Redislocation was observed in only one hip. CONCLUSION: Surgical treatment of the older patients with neglected DDH is technically difficult, and the results are prone to complications. The technique outlined by Prof. Dr. Güngör Sami Cakirgil, a renowned specialist in DDH surgeries in Türkiye who has made notable contributions to the relevant research, yields satisfactory outcomes when employed under suitable circumstances.

Does medullary diameter to stem width ratio and stem length affect outcomes of revision total knee arthroplasties? A case series.

OBJECTIVES: This study aimed to investigate the relationship between the ratio of stem size to intramedullary canal diameter, stem length, and functional outcome in revision total knee arthroplasty (RTKA) procedures, which remains largely unexplored in the current literature. PATIENTS AND METHODS: A single surgeon series of RTKA procedures performed between October 2014 and November 2022 were included in this case series, and data were analyzed retrospectively. A total of 32 patients (27 females, 5 males; mean age: 73.2±8.1 years; range, 52 to 88 years) were identified, with a minimum follow-up period of five months and a maximum of eight years. Filtering the patients based on >24 month follow-up, we were left with 13 patients aged between 65 and 88 (mean 74.9±6.9) years. The latest X-rays of patients were analyzed, and the ratio of intramedullary canal diameter to stem width was calculated for both femur and tibia in both anteroposterior and lateral planes. Household income, preoperative C-reactive protein, erythrocyte sedimentation rate, comorbidities, body mass index, and implant dimensions were also recorded. Postoperative Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Short Form-12 (SF-12) scores, and range of motion (ROM) measurements were used to evaluate functional outcome. RESULTS: A moderate negative relationship between the tibial canal fill ratio (CFR) in anteroposterior views and ROM of the patients was noted. Additionally, a significant positive correlation was found between SF-12 physical score and CFR in lateral view. A moderate level of correlation between femoral CFR in anteroposterior views was also established. Due to insufficient data, joint ROM data did not show normal distribution. Therefore, a cutoff value indicating the relationship between the stem size and knee ROM could not be calculated using receiver operating characteristic analysis. Multiple regression analysis did not yield significant results, suggesting that hypothesized predictor variables were not sufficient to predict the variation in functional scores. Otherwise, no clear statistical importance or correlation between functional scores, such as WOMAC or SF-12, and CFR was found. CONCLUSION: In conclusion, the findings suggest that other factors, such as other patient characteristics, surgical techniques, or implant designs, may have a more substantial impact on the functional outcomes in RTKA patients.

Total hip arthroplasty in patients with coxarthrosis due to developmental dysplasia of the hip: Is fixation of the subtrochanteric osteotomy necessary?

OBJECTIVES: This study aims to analyze the clinical, functional, and radiographic results of patients with Crowe type IV developmental dysplasia of the hip (DDH) sequelae undergoing cementless total hip arthroplasty (THA) with transverse subtrochanteric shortening osteotomy without fixation at the osteotomy site. PATIENTS AND METHODS: Between March 2013 and February 2020, a total of 42 hips of 34 patients (8 males, 26 females; mean age: 50.7±11.7 years; range, 27 to 76 years) with Crowe type IV DDH treated with subtrochanteric shortening osteotomy combined with primary cementless THA were retrospectively analyzed. Each case was evaluated to the Harris Hip Score (HHS). Crowe classification, location of the rotation center of hip, loosening of the implants, and union at the osteotomy line were evaluated radiologically. RESULTS: The mean follow-up was 57.9±31.5 (range, 24 to 192) months. The mean interval to complete bone union in 40 hips (95%) after surgery was 3.5±0.9 (range, 2 to 6) months. The mean preoperative HHS scores of the patients was 35.6±6.86, while the scores increased to 91.53±5.41 at the final follow-up (p<0.001). CONCLUSION: Our study results suggest that excellent clinical and radiological results can be obtained in Crowe type IV dysplastic hips in patients undergoing THA with the rectangular femoral component and transverse shortening osteotomy technique, without fixation at the osteotomy site.

The effect of brace on apical vertebral derotation in adolescent idiopathic scoliosis.

PURPOSE: The current study aims to evaluate the effect of Boston brace treatment on apical vertebral derotation in adolescent idiopathic scoliosis (AIS) patients receiving conservative treatment. METHODS: The study included 51 AIS patients, consisting of 8 males and 43 females, with Cobb angles between 25° and 45° and Risser's findings ranging from 0 to 4. The mean age of the participants was 12.20 ± 1.34 years. All patients were treated with the Boston brace for a minimum of 2 years and evaluated before the brace, during early brace use, and at the last follow-up. Radiographs were assessed to measure apical vertebral rotation (AVR) and vertebral translation (AVT). The SRS-22 questionnaire was used to evaluate patient outcomes. RESULTS: The radiographs of patients were evaluated over a mean follow-up period of 32.42 ± 8.65 months. Before the brace, the mean AVR was 2.1 ± 0.6, while it was 1.1 ± 0.5 with the brace. At the last follow-up, the mean AVR was 1.3 ± 0.5 (p < 0.001). Before the brace, the mean AVT was 36.4 ± 9.6 mm, which decreased to 16.7 ± 7.3 mm with the brace (p < 0.001). At the last follow-up, the mean AVT was 19.8 ± 8.1 mm (p < 0.001). The use of the brace had a significant corrective effect on thoracolumbar and lumbar curvatures compared to before the brace (p < 0.001). CONCLUSION: The findings of the current study suggest that the use of a Boston brace in the conservative treatment of AIS is effective in correcting the coronal and sagittal plane deformities, including thoracic, thoracolumbar, and lumbar curvatures, and in reducing apical vertebral rotation and translation.

Intermittent pedicle screw application provides better kyphosis restoration in adolescent idiopathic scoliosis for Lenke type 1 and type 2 curves.

PURPOSE: There is still no consensus on the optimum pedicle screw density required for the desired thoracic kyphosis restoration in adolescent idiopathic surgery (AIS). The aim of this study to evaluate the effect of pedicle screw density on thoracic kyphosis restoration in AIS surgery. METHODS: The data of 106 patients from two centers that operated for Lenke type 1 and 2 AIS were retrospectively reviewed. Two groups were constituted according to the pedicle screw density: intermittent pedicle screw constructs (IPSC) (n = 52 patients) and consecutive pedicle screw construct (CPSC) (n = 54 patients) groups. The preoperative and at least 24-month follow-up radiographs and SRS-22 scores were evaluated. The Cobb angle of the main and concomitant curves in the coronal plane and the sagittal plane were measured and compared. RESULTS: The mean follow-up period for the IPSC and CPSC groups was 72.3 ± 37.2 and 62.9 ± 28.8 months, respectively. In the SRS-22 questionnaire, there was no significant difference between the two groups in terms of self-image/appearance domain scores (p = 0.466), but better results were obtained in the IPSC group in terms of treatment satisfaction domain scores (p = 0.010) and better thoracic kyphosis restoration was achieved in IPSC group radiologically for Lenke type 1 curves with - 81.4 ± 81.4% in the IPSC group and 6.8 ± 83.8% in the CPSC group (p < 0.001). CONCLUSION: It was considered that better thoracic kyphosis restoration could be achieved with the less lordotic effect of IPSC in Lenke type 1 curves. Although the current situation had a significant impact on radiological outcomes, its effect on SRS-22 scores was limited.

Bio-engineered synovial membrane to prevent tendon adhesions in rabbit flexor tendon model.

During tendon injuries, the tendon sheath is also damaged. This study aims to test effectiveness of engineered tendon synovial cell biomembrane on prevention of adhesions. Forty New Zealand Rabbits enrolled into four study groups. Engineered synovial sheath was produced by culturing cell suspension on fabricated collagen matrix membrane. Study groups were: tendon repair (group A), tendon repair zone covered with plane matrix (Group B), synovial suspension injection into the zone of repair over matrix (Group C), and biomembrane application (Group D). Biomechanical evaluations of tendon excursion, metacarpophalangeal and proximal interphalangeal joints range of motion, H&E and Alcian Blue with neutral red staining, and adhesion formation graded for histological assessments were studied. Ten non-operated extremities used as control. Tendon excursions and range of motions were significantly higher and close to control group for Group D, p < 0.05. Adhesion formation was not different among Groups C, D, and Control, p > 0.005. Hyaluronic acid synthesis was demonstrated at groups C and D at the zone of injury. Application of synovial cells into the tendon repair zone either by cell suspension or within a biomembrane significantly decreases the adhesion formation. Barrier effect of collagen matrix and restoration of hyaluronic acid synthesis can explain the possible mechanism of action.