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.

Don't miss it: Extremity-located cyst hydatid may mimic soft tissue tumors.

OBJECTIVES: In this study, we present our experience in patients with hydatid cysts located intramuscularly. PATIENTS AND METHODS: Between May 2018 and May 2023, a total of 11 patients (3 males, 8 females; mean age: 29.1±13.6 years; range, 8 to 56 years) with intramuscular hydatid cysts were retrospectively analyzed. Demographic data, laboratory values, serological test results, location and size of the cyst, radiological imaging findings, and complications were recorded. RESULTS: The mean follow-up was 44.3±17.3 (range, 5 to 60) months. The mean mass size at the time of admission was 5.4±3.3 (range, 2 to 14) cm. Serologic tests were positive in the majority of cases (72.7%). Eosinophilia was negative in 72.7% patients. The rate of isolated muscle involvement was 81.8%. The rate of lower extremity involvement was 72.7%. The most common involvement was leg (36.4%), thigh (18.2%), and shoulder (18.2%). One patient developed compartment syndrome after cyst rupture during neoadjuvant antihelmintic therapy. There was no recurrence in any of the patients. CONCLUSION: Hydatid cysts should be considered in the differential diagnosis of slowly growing, deeply located, painless soft tissue masses, particularly in endemic areas. Although it is a rare complication, compartment syndrome may develop after spontaneous cyst rupture. Neoadjuvant antihelmintic chemotherapy can reduce complications. The combination of total surgical excision and chemotherapy yields successful results in the treatment of hydatid cysts located in the muscle.

The middle glenohumeral ligament: a classification based on arthroscopic evaluation.

BACKGROUND: Although middle glenohumeral ligament (MGHL) variations have been shown in the literature, their clinical effect and relationship with intra-articular pathologies have yet to be revealed, except for the Buford complex. This study was designed to classify MGHL and to reveal its relationship with clinical pathologies. METHODS: A total of 843 consecutive shoulder arthroscopies were evaluated retrospectively, and a classification system was proposed for MGHL with regard to its structure and its relation to the anterior labrum. The associations of each MGHL type with superior labrum anterior-posterior (SLAP) lesions, subscapularis tears, and anterior instability were investigated. RESULTS: MGHL variations were grouped into 6 types according to the classification. A significant difference in favor of type 6 MGHL (Buford complex) was observed in the distribution of SLAP lesions (P < .001). There was no significant difference between MGHL types and the distribution of anterior instability history (P = .131) and subscapularis tears (P = .324). CONCLUSION: SLAP lesions accompany type 6 MGHLs (Buford complex) significantly more frequently than other types. There is also a negative relation between the anterior instability and thicker MGHL variants.