Polymethyl methacrylate (PMMA) bone cement has been a transformative material in orthopedics since its introduction in the mid-20th century. Originally used in dental medicine, PMMA was adopted for orthopedic applications by Sir John Charnley in the 1950s, significantly enhancing joint replacement surgeries. The primary appeal of PMMA lies in its biocompatibility, mechanical strength, and ease of handling, making it a favored choice for various orthopedic procedures, including arthroplasties and limb-salvage surgeries. However, the exothermic polymerization process of PMMA poses a risk of thermal necrosis in the surrounding bone tissue, as local temperatures can exceed 70 °C, causing damage to osteocytes. Research has sought to mitigate these risks by optimizing mixing techniques, reducing cement mantle thickness, and incorporating cooling methods. Recent advancements, such as the use of phase-change materials (PCMs) and alternative monomers, have shown promise in lowering the exothermic peak during polymerization. Other strategies include pre-cooling the cement and prosthetic components and using composite cement. Despite these innovations, managing the balance between minimizing heat generation and maintaining mechanical properties remains a challenge. The impact of thermal necrosis is significant, compromising implant stability and osseointegration. Understanding the complex interactions between PMMA’s thermal properties and its clinical outcomes is essential for improving orthopedic surgical practices and patient recovery.

Background: Prior trials investigating the treatment of symptomatic osteoarthritis (OA) with hyaluronic-acid-derived products injections have provided optimistic results. The study was directed to assess the effectiveness of an innovative hyaluronic-acid-based hydrogel (Hymovis^®) in the treatment of symptomatic knee OA. Methods: A prospective, single-center, clinical trial was performed. Thirty-five patients with degenerative knee OA were included. Inclusion criteria were: age between 45–80, radiographic Kellgren grade II or III osteoarthritis, minimum 35 mm score on the Visual Analogue Scale (VAS), pain for at least 6 months and agreement to participate in the study. Patients received two injections at a one-week interval. The evaluator assessed the patients using the Western Ontario and McMaster University Osteoarthritis Index (WOMAC) and VAS. Evaluation was performed before, at 2 and 6 months after the injections. Results: A significant improvement on the WOMAC Index pain subscale was observed at 6 months after the injection. At two months, pain subscale score decreased from 10.34 to 9.34. At six months, a significant decrement in pain parameters compared to baseline was observed (from 10.34 to 7.72; p = 0.0004). Median points on VAS significantly ameliorated after 6 months (from 74.2 to 57.3 cm; p < 0.0001). Regarding physical function, a statistically significant difference compared to baseline was observed at the end of the study (from 29.74 to 25.18; p = 0.0025). WOMAC Index stiffness component did not differ from baseline at any time during follow-up. Conclusions: Pain relief installed with a delayed on-set but had a prolonged duration. The novel hyaluronic acid-based hydrogel (Hymovis^®) had effective results, particularly after six months post-injections and offers a therapeutic advancement in the treatment of moderate to severe osteoarthritis.

Rapidly progressive hip osteoarthritis (RPOH) is a rare and severe form of osteoarthritis (OA), marked by the rapid degeneration and destruction of the femoral head, often within months. Despite its unclear etiology, several factors such as subchondral fractures and immune responses have been proposed as possible contributors. This narrative review aims to synthesize current knowledge on the pathogenesis, risk factors, clinical presentation, imaging features, and grading systems of RPOH. Predominantly affecting elderly females, RPOH presents distinctive challenges in both diagnosis and management due to its abrupt onset and severity. Known risk factors include advanced age, female gender, obesity, intra-articular corticosteroids use, and long-term hemodialysis. Clinically, RPOH is characterized by severe pain during active weight-bearing movements, despite patients presenting a normal range of motion during passive examination in the early stages. While several classification systems exist, there is no universal standard, complicating differential diagnosis and clinical approaches. This review emphasizes the necessity for early diagnostic methods utilizing specific biomarkers, rapid differential diagnosis, and targeted, personalized interventions based on individual risk factors.

Background: The objective of the arthroscopic treatment in tibial spine avulsion fractures (TSAF) is to achieve firm reduction and strong internal fixation while still having the patient undergo a minimally invasive procedure. Material and methods: The study was performed on 12 young patients with avulsion fracture of the anterior tibial spine. All 12 patients had type 3 Modified Meyers and McKeever fractures. The injury mechanism was direct anterior to posterior trauma in full leg length hyperextension with sport trauma reported in all cases. The physical examination revealed decreased range of motion, extension deficit, and pain during walking. Radiology, MRI, and CT pathologic findings described complete fracture of the anterior tibial spine with no clear signs of callus formation at the time of examination. All patients underwent arthroscopic suture surgical treatment. The Tegner, the Lysholm, and the International Knee Documentation Committee (IKDC) scores were used to evaluate subjective outcomes at three and six months after the surgery. Radiographs were used to assess callus formation and healing status of the fracture. Results: The mean IKDC score was 33.4 ± 23.3 (p = 0.032) preoperatively and 84.2 ± 14.3 at final follow-up (p = 0.0032, CI = 95%). The mean Tegner score improved from 3.8 ± 1.1 pre-operatively to 6.7 ± 2.2 at six months follow-up (p = 0.0231, CI = 95%). The Lysholm score differed significantly at baseline compared to final follow-up (53.7 ± 17.3 vs. 87.7 ± 9.9; p = 0.0066, CI = 95%). In all cases (n = 12), the radiographs taken after six months revealed the healing of the fracture in the anatomic position without secondary displacement. No functional knee instability was detected at the end of the study. Conclusions: The study provides preliminary promising results regarding fracture healing, knee stability, and functional subjective scores. Patient selection was a major factor of success prediction for this technique.

Objectives: Polymethyl methacrylate (PMMA) bone cement is vital for prosthetic fixation in orthopedic surgery, yet its exothermic polymerization can exceed 80 °C, surpassing the 50 °C threshold for thermal osteonecrosis, risking implant failure. This pilot study assesses two cooling strategies—precooling cement components and saline irrigation on the polymerization temperature and compressive strength of antibiotic-loaded PMMA, comparing hand mixing (HM) and vacuum mixing (VM) to optimize thermal management while preserving mechanical integrity in controlled settings relevant to orthopedic applications. Methods: Antibiotic-loaded Simplex bone cement (Stryker, Kalamazoo, MI, USA) was prepared using HM and VM, per ISO 5833. Each batch was divided into three groups: control, precooled (components at 6 °C overnight), and saline irrigation (8 °C saline during setting). Each group included 20 cylindrical samples (1.5 cm × 3 cm), cured for 24 h. Core temperatures were monitored with embedded thermometers, and compressive strength was measured in megapascals (MPa) using a hydraulic press (C092-06, MATEST). Welch’s t-test was used for statistical analysis. Results: HM controls reached 76.2 °C, precooled 63.6 °C, and saline 66 °C; VM controls hit 71.8 °C, precooled 58.8 °C, and saline 63.6 °C. HM strengths were 16–17 MPa, with precooling reducing to 16.49 MPa (p = 0.051) and saline maintaining 17.07 MPa (p = 0.820). VM strengths were 76–80 MPa, with precooling at 78.45 MPa (p < 0.001) and saline at 76.77 MPa (p = 0.010). Failure modes varied: controls (uniform cracking), precooled (shear failure), and saline (mixed cracking/crumbling). Conclusions: Precooling significantly lowers temperatures but compromises strength in HM samples, limiting its use in load-bearing applications. Saline irrigation offers moderate thermal control while preserving mechanics, particularly in HM, suggesting a viable strategy for reducing thermal necrosis risk. VM ensures superior strength, supporting safe cooling application.