骨形成不全症

BACKGROUND: Osteogenesis imperfecta (OI) is a genetic disorder of type I collagen associated with a higher risk of musculoskeletal injury. While fracture management in OI is well described, the safety and outcomes of knee arthroscopy for intra-articular pathology in pediatric and adolescent patients with OI remain unknown. The purpose of this study is to evaluate indications, complications, revision surgery rates, and return to baseline activity following knee arthroscopy in this population. METHODS: A multicenter retrospective case series was performed on pediatric and adolescent patients with OI who underwent knee arthroscopy between January 2004 and March 2025. Patients with <6 months of follow-up were excluded. Demographic information, diagnoses, procedures, complications, revision surgeries, time to regain full range of motion, and time to return to sport or baseline activity were recorded. Complications were classified using a modified Clavien-Dindo-Sink system. RESULTS: Twenty patients (29 arthroscopic procedures) were included, with a mean age at surgery of 15.5 ± 3.2 years. The most common indications were meniscal injury (41.4%), patellar instability (31.0%), and fracture (27.6%). The most frequent procedures were meniscus repair or meniscectomy (24.1%), patellar stabilization surgery (24.1%), and anterior cruciate ligament reconstruction (17.2%). Postoperative complications of any type occurred after 48.3% of procedures, and 35% of patients required at least one revision surgery. No life-threatening or limb-threatening complications occurred. Seventeen patients (85%) returned to full baseline activities at a mean of 182 days postoperatively. CONCLUSIONS: Knee arthroscopy in pediatric and adolescent patients with OI is safe and can effectively restore function and allow return to baseline activity. However, patients should be counseled regarding higher rates of postoperative complications and revision surgery compared with the general pediatric and adolescent population. LEVEL OF EVIDENCE: Level IV-case series.

Osteogenesis imperfecta (OI) is a rare genetic disorder but is the most common disorder of bone etiology with little known about the impact of physiologic factors on fracture risk. Finite element analysis (FE) models of OI bone have been previously developed to examine fracture risk during ambulation and various daily activities of the femur and tibia. This study aims to further investigate the impact of long bone deformity and muscle activation forces in children and adolescents with OI. Pediatric femoral FE models of normal, OI type I, and OI type III bone material properties assessed effects of lateral bowing versus increased gluteus medius and gluteus maximus force production on bone injury risk. Models incorporating increased lateral bowing and muscle forces showed up to 7.56% higher stress levels than the standard model with no bowing and normal muscle forces, with muscle forces having a greater impact than lateral bowing. This study provides quantitative information to help establish methodology for FE analysis to assess femoral fracture risk in individuals with OI.

Musculoskeletal disorders (MSDs) are primarily characterized by joint, bone, and connective tissue involvement, but they can also present with ocular manifestations that carry diagnostic and clinical significance. These findings such as uveitis, blue sclera, lens subluxation, and scleritis may serve as early markers of systemic disease or indicate ongoing inflammation that affects orthopaedic decision making. Despite their relevance, ocular symptoms are frequently underrecognized in orthopaedic settings, potentially delaying comprehensive care. This narrative review aims to explore the spectrum of MSDs with documented ocular involvement, examining the underlying pathophysiological mechanisms, clinical implications for orthopaedic specialists, and current recommendations for interdisciplinary management and ophthalmology referral. A literature search was conducted using PubMed, Scopus, and Google Scholar, including peer-reviewed studies published between 2016 and 2025. High-risk conditions, such as osteogenesis imperfecta, Marfan syndrome, rheumatoid arthritis, and juvenile idiopathic arthritis, were emphasized because of their ocular complexity and orthopaedic relevance. Ophthalmologic evaluation in selected musculoskeletal populations can aid in early diagnosis, improve perioperative safety, and support holistic patient care. Incorporating structured identification of patients requiring ophthalmology referral into orthopaedic protocols, especially for syndromic, pediatric, and inflammatory conditions, represents a practical step toward more comprehensive musculoskeletal management.

Type I collagen homotrimer is associated with age-related musculoskeletal, cardiovascular and fibrotic diseases - in addition to cancer - due to over-production of the alpha-1(I) chain from COL1A1, or inactivation of COL1A2. Type I collagen homotrimer in the osteogenesis imperfecta model oim does not cause bone fragility but exacerbates the oim phenotype. Here Col1a2 null and oim tail tendons were analysed to elucidate the role of collagen homotrimer in soft collagenous tissues. In Col1a2 null homozygotes, tendon diameter was reduced at 8 weeks old, whilst at 18 and 52 weeks old maximum modulus and hysteresis strain energy density were reduced and strain at maximum modulus was increased. Failure strain increased at 52 weeks. Oim homozygotes had additional changes in tendon diameter at 18 weeks, with narrower collagen fibrils and reduced hysteresis strain energy density at 8 weeks old, and reduced percentage hysteresis at both ages. There was evidence of type I collagen homotrimer in Col1a2 null heterozygotes, which had significant but less pronounced changes in failure strain, strain at maximum modulus and hysteresis strain energy at 18 weeks than homozygotes. Proteomics identified altered matrix protein composition in Col1a2 null and oim homozygotes whilst tissue fluorescence increased in Col1a2 null homozygotes at 52 weeks. Hence homotrimeric type I collagen affects the material properties and matrix protein composition of tail tendon following adolescence, whilst the oim mutation introduces earlier and additional alterations to energy dissipation. STATEMENT OF SIGNIFICANCE: Type I collagen is normally a heterotrimeric molecule but homotrimers can also be formed. To study how type I collagen homotrimer affects tissues, genetic inactivation of Col1a2 in mice was used to study the effect on tail tendon biomechanics and protein composition. Tendons comprising solely homotrimeric collagen displayed altered biomechanical properties that were more pronounced at older ages, indicative of damage accumulation or adaptive responses. An altered protein composition indicates both compensatory over-production and corresponding loss of other matrix proteins that may modulate tissue biomechanics. Findings in heterozygotes indicate that even partial homotrimer production is sufficient to alter tendon properties and provides insight into the tissue-level consequences of musculoskeletal and cardiovascular disease associated with type I collagen homotrimer production.

INTRODUCTION: Osteogenesis imperfecta (OI) is a rare genetic disorder characterized by significant bone fragility and progressive skeletal deformities. While cubitus varus (CV) is a common complication after pediatric supracondylar fractures, deformities exceeding 40° in patients with OI are exceptionally rare. This report describes a severe case managed through a staged surgical strategy to overcome challenges associated with bone fragility. CASE REPORT: A 4-year-old male with OI presented with a 45° CV deformity of the right elbow following recurrent fractures. Due to extreme bone fragility and the complexity of the 3D deformity, a staged surgical plan was implemented. The initial surgery prioritized osteotomy site stability and coronal correction using a stepped cut osteotomy. Once bone union was achieved, a second corrective wedge osteotomy was performed a year later to refine the alignment. At the final follow-up at age 7, the patient maintained a 15° carrying angle and a good range of motion. The improved alignment successfully prevented further fractures. CONCLUSION: For complex pediatric elbow deformities with underlying bone fragility, a staged approach prioritizing stability over immediate anatomical perfection is a realistic strategy. Establishing a shared understanding with the family regarding the potential necessity of multiple procedures is essential for clinical success and safety.