A 35-year-old man comes with a history of musculoskeletal pain. Which of the following suggests that the pain is non-articular?

Explanation

## Correct Answer: C. Painless on passive movement Non-articular pain (musculoskeletal pain originating from muscles, tendons, ligaments, fascia, or bursae) has a fundamentally different pain mechanism than articular (joint) pain. The discriminating feature is that **non-articular pain is painless on passive movement** because passive motion does not stress the extra-articular structures. When a joint is passively moved, the intra-articular surfaces, synovium, and joint capsule are stretched and compressed; if pain is present during passive movement, it indicates articular involvement. Conversely, non-articular structures (muscle-tendon units, bursa, ligaments) are stressed primarily during active contraction or specific directional movements. Passive movement, which relaxes muscles and does not load tendons or ligaments, typically does not reproduce non-articular pain. This is a cardinal clinical sign taught in Indian orthopedic practice (Bailey & Love, Park's Textbook) to differentiate the site of pathology. A patient with myofascial pain, tendinitis, or bursitis will report pain during active use but relief with passive movement, whereas a patient with osteoarthritis or inflammatory arthritis will have pain on both active and passive movement due to intra-articular pathology. ## Why the other options are wrong **A. Presence of crepitation** — Crepitation can occur in both articular and non-articular conditions. Articular crepitus (bone-on-bone grinding in osteoarthritis) and non-articular crepitus (tendon crepitus in tenosynovitis, subcutaneous emphysema) are both possible. This sign is non-specific and does not reliably differentiate articular from non-articular pain, making it an unreliable discriminator. **B. Swelling** — Swelling is a non-specific sign present in both articular and non-articular conditions. Joint effusion causes articular swelling; bursitis, tenosynovitis, and muscle hematoma cause non-articular swelling. The presence of swelling alone cannot distinguish between articular and non-articular pathology, as both can present with localized edema. **D. Pain in both movement and at rest** — While pain at rest and during movement is more suggestive of articular pathology (inflammatory or degenerative joint disease), non-articular conditions like severe myofascial pain syndrome, bursitis, or tendinitis can also cause pain at rest due to inflammation and muscle guarding. This is not a reliable sole discriminator between articular and non-articular pain. ## High-Yield Facts - **Painless passive movement** is the cardinal sign of non-articular pain; pain on passive movement indicates articular involvement. - **Active movement pain with passive relief** is pathognomonic for non-articular musculoskeletal pathology (muscle, tendon, bursa, ligament). - **Articular pain** is reproduced by both active and passive movement because intra-articular structures are stressed in both scenarios. - **Crepitation and swelling** are non-specific signs present in both articular and non-articular conditions and cannot be used as sole discriminators. - **Selective directional pain** (pain in one direction but not another) often indicates non-articular pathology, whereas **multidirectional pain** suggests articular disease. ## Mnemonics **PROM vs AROM in Articular vs Non-Articular Pain** **Articular**: Pain on both AROM (Active Range of Motion) and PROM (Passive Range of Motion). **Non-Articular**: Pain on AROM only, PROM painless. Use this when examining any joint complaint in OPD to rapidly localize the pathology. **APE Rule (Articular Pain Exam)** **A**ctive + **P**assive = **E**xtension of pain suggests Articular pathology. If only Active hurts, think non-articular (muscle, tendon, bursa). ## NBE Trap NBE may trap students who confuse the presence of swelling or crepitation (which can occur in both conditions) with a specific sign of non-articular pain. The key is recognizing that **passive movement specifically tests intra-articular structures**, and its absence of pain is the discriminating feature. ## Clinical Pearl In Indian outpatient orthopedic practice, when a 35-year-old laborer presents with musculoskeletal pain, the first clinical test is passive movement of the affected joint. If pain is absent on passive movement but present on active movement, you can confidently reassure the patient that the joint itself is not damaged—the problem is muscular or tendinous, often from overuse or poor ergonomics at work. This simple bedside test saves unnecessary imaging and guides conservative management (rest, physiotherapy, NSAIDs). _Reference: Bailey & Love's Short Practice of Surgery (Ch. Orthopedics); Park's Textbook of Preventive and Social Medicine (Clinical Examination section)_