Occupation-specific Physiotherapy and Ergonomic Rehabilitation in Seronegative Radiographic Axial Spondyloarthritis in a Young Farm Labourer: A Case Report

Axial Spondyloarthritis (axial SpA) is often missed in young people, often confused with mechanical Low Back Pain (LBP), especially among those with heavy manual labour, resulting in poor management and loss of function. This case report details a 22-year-old male farm labourer who had suffered from chronic LBP (4/10 with activity and 7/10 at rest) for 1.5 years, progressive stiffness in the spine (morning stiffness> 60 minutes), and decreased work capacity. On clinical examination, decreased lumbar mobility (flexion 40°), decreased chest expansion (2.5 cm), posterior chain muscle tightness, and guarded movement without neurological deficit were noted. Laboratory investigations revealed an elevated ESR (42 mm/hour), a borderline normal C-Reactive Protein (CRP: 4.2 mg/L; reference <5 mg/L), which, while within the normal range, may carry diagnostic relevance in axial SpA, and negative HLA-B27 and rheumatoid factor. Unilateral grade II sacroiliitis (modified NY criteria) and vertebral squaring with early syndesmophytes were seen on radiographs, compatible with seronegative radiographic axial SpA. The patient fulfilled the Assessment of SpondyloArthritis International Society (ASAS) criteria for radiographic axial SpA (sacroiliitis on imaging plus ≥1 SpA feature). Amor classification criteria confirmed the diagnosis at the minimum threshold (score 6, threshold ≥6); notably, the radiological sacroiliitis item scored 0 points as unilateral grade II sacroiliitis does not meet the Amor radiological criterion (which requires bilateral ≥ Grade II or unilateral ≥ Grade III), and the total of 6 points was reached through clinical features alone. Baseline assessment indicated high disease activity and functional limitation {Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) 5.6; Functional Index (BASFI): 5.3; Metrology Index (BASMI): 2.4; Global Score (BAS-G): 8.5}. A structured 12-week physiotherapy program including spinal mobility and extension exercises, flexibility training, breathing exercises and postural correction was implemented, along with occupationspecific ergonomic interventions including neutral spine lifting, load redistribution (≤15 kg), work modification, and use of longhandled tools. At 12-week follow-up, clinically meaningful improvements were observed: BASDAI score was 3.4, BASFI score was 3.1, BASMI score was 1.6, BAS-G score was 4.2, pain score 3/10 during activity and 5/10 at rest, and a 34% improvement in work productivity (Work Productivity and Activity Impairment (WPAI) questionnaire). Improvements in BASDAI and BASFI exceeded established Minimal Clinically Important Difference (MCID) thresholds. This case emphasises early recognition of inflammatory back pain. It highlights the role of physiotherapy combined with occupation-specific ergonomic modifications in improving function and work participation among manual workers with seronegative axial SpA.