Endophenotypes of Primary Osteoarthritis of the Hip Joint in the Bulgarian Population over 60 Years Old.

Aim. To identify subgroups of patients with primary osteoarthritis of the hip joint (pHOA) with similar imaging and laboratory findings, disease evolution, and response to conventional therapies. Methods. We performed further statistical analyses on patient data from two published, double-blind, randomized, and placebo-controlled studies (DB-RCTs), which examined the effects of intra-articular corticosteroids (ia-CSs), hyaluronic acid (ia-HA)-KИ-109-3-0008/14.01.2014, and intravenous bisphosphonates (iv-BPs) -KИ- 109-3-0009/14.01.2014 compared to the country's standard pHOA therapy. The data span an 8-year follow-up of 700 patients with pHOA, including: 1. Clinical parameters (WOMAC-A, B, C, and T; PtGA). 2. Laboratory markers (serum calcium and phosphate levels; 25-OH-D and PTH, markers for bone sCTX-I and cartilage uCTX-II turnover). 3. Radiological indicators: X-ray stage (Kellgren-Lawrence (K/L) and model (Bombelli/OOARSI), width (mJSW), speed (JSN mm/year), and zone of maximum narrowing of the joint space (max-JSN)-determining the type of femoral head migration (FHM). 4. DXA indicators: bone geometry (HAL; NSA; and MNW); changes in regional and total bone mineral density (TH-BMD, LS-BMD, and TB-BMD). 5. Therapeutic responses (OARSI/MCII; mJSW; JSNmm/yearly) to different drug regimens (iv-BP -zoledronic acid (ZA/-5 mg/yearly for 3 years)); ia-CS 40 mg methylprednisolone acetate, twice every 6 months; and ia-HA with intermediate molecular weight (20 mg/2 mL × 3 weekly applications, two courses every 6 months) were compared to standard of care therapy (Standard of Care/SC/), namely D3-supplementation according to serum levels (20-120 ng/mL; target level of 60 ng/mL), simple analgesics (paracetamol, up to 2.0 g/24 h), and physical exercises. The abovementioned data were integrated into a non-supervised hierarchical agglomerative clustering analysis (NHACA) using Ward's linkage method and the squared Euclidean distance to identify different endophenotypes (EFs). Univariate and multivariate multinomial logistic regression analyses were performed to determine the impact of sex and FHM on clinical and radiographic regression of pHOA. Results. A baseline cluster analysis using incoming (M0) patient data identified three EFs: hypertrophic H-HOA, atrophic A-HOA, and intermediate I-HOA. These EFs had characteristics that were similar to those of patients grouped by radiographic stage and pattern ('H'-RPs, 'I'-RPs, and 'A'-RPs), p < 0.05). The repeated cluster analysis of M36 data identified four EF pHOAs: 1. Hypertrophic (slow progressors, the influence of the type of femoral head migration (FHM) outweighing the influence of sex on progression), progressing to planned total hip replacement (THR) within 5 (K/LIII) to 10 (K/LII) years. 2. Intermediate (sex is more important than the FHM type for progression) with two subgroups: 2#: male-associated (slow progressors), THR within 4 (K/LIII) to 8 years. (K/LII). 2* Female-associated (rapid progressors), THR within 3 (K/LIII) to 5 (K/LII) years. 3. Atrophic (rapid progressors; the influence of FHM type outweighs that of sex), THR within 2 (K/LIII) to 4 (K/LII) years. Each EF, in addition to the patient's individual progression rate, was also associated with a different response to the aforementioned therapies. Conclusions. Clinical endophenotyping provides guidance for a personalized approach in patients with pHOA, simultaneously assisting the creation of homogeneous patient groups necessary for conducting modern genetic and therapeutic scientific studies.

The diagnostic value of ultrasound in the assessment of soft tissue masses in rheumatology practice - a case series of 4 patients.

A great number of studies have proved the added value of musculoskeletal ultrasound (MSUS) in the diagnosis, assessment of disease activity and treatment response in both inflammatory and degenerative rheumatic diseases. However, it is a frequent scenario that rheumatologists should also assess patients with various soft tissue masses, referred to their practices. In such cases, MSUS could be a valuable and precise tool that helps in the evaluation and triage of these lesions. Hereafter, we describe a case series, where MSUS played a decisive role in the diagnostic process and allowed for prompt patients' management.

Severe Acro-osteolysis Mimicking Arthritis Mutilans in a Patient with Primary Hyperparathyroidism: A Case Report.

BACKGROUND: Primary hyperparathyroidism (PHPT) should be considered in the differential diagnosis of a patient with suspected secondary osteoporosis, and severe osteoporosis with multiple fractures is frequently the first clinical manifestation of the disease. CASE PRESENTATION: Mutilating arthritis (arthritis mutilans) can be part of the clinical presentation of a number of rheumatic diseases, most commonly seen in psoriatic arthritis, rheumatoid arthritis, and juvenile idiopathic arthritis, but also in systemic lupus, systemic sclerosis, and multicentric reticulohistiocytosis. Evidence exists that subperiosteal and subchondral bone resorption, seen in PHPT, could induce the so-called 'osteogenic synovitis', which could eventually lead to the development of a secondary osteoarthritis with bone deformities. CONCLUSION: Here, we present a case report of a patient initially diagnosed with PHPT who presented with mutilating arthritis of the finger joints and discuss whether the severe acro-osteolysis is a manifestation of the endocrinopathy or whether there is a co-existing undiagnosed inflammatory joint disease.