Rib Stress Fractures & Intercostal Injuries

Rib stress fracture: insidious-onset chest wall pain during a training load increase, especially in rowers. The progression is pain late in training, then early in training, then with daily activities and breathing, then at rest. Pain is worse with the specific sport, deep breathing, coughing, twisting, lifting, and lying on the affected side. First rib stress fracture presents with pain at the base of the neck or supraclavicular area, possibly radiating to the shoulder or arm.

Examination: focal bony point tenderness over the affected rib is the most important finding - palpate each rib individually. Rib compression (rib spring) test - AP or lateral chest compression transmits stress to the fracture site and reproduces pain. Pain with deep inspiration and with resisted trunk rotation. Periosteal thickening may be palpable in established fractures. For first rib: supraclavicular tenderness, pain on resisted shoulder elevation or neck side-flexion, and upper-limb neurovascular assessment.

Intercostal muscle injury: sudden sharp, tearing, or catching pain during a specific movement (rotation, bowling, serving, coughing, lifting) - the patient identifies the exact moment. Pain is worse with deep inspiration, coughing, sneezing, laughing, twisting, and reaching. Examination shows tenderness in the intercostal space (between the ribs, not over a rib) and pain with resisted trunk rotation.

A useful clinical clue: focal bony tenderness raises suspicion of rib stress injury; intercostal-space tenderness supports soft tissue injury. Overlap occurs and imaging may be needed.

Key differentials: costochondritis, Tietze syndrome, slipping rib syndrome (ribs 8 to 10, clicking, positive hooking manoeuvre), costovertebral or costotransverse dysfunction, intercostal neuralgia, herpes zoster, pneumothorax, PE, pneumonia, and cardiac causes.

Rib stress fractures are frequently missed - a high index of suspicion is required. Plain radiographs (PA and lateral chest, plus dedicated rib views if needed) are often normal early; late findings include periosteal reaction, cortical thickening, callus, and fracture line. Chest X-ray remains valuable for excluding pneumothorax, pneumonia, and pulmonary pathology.

MRI is the preferred advanced investigation in most UK SEM settings - it demonstrates bone marrow oedema, periosteal oedema, and a discrete fracture line, and distinguishes stress reaction from stress fracture. Particularly valuable for first rib stress fractures and equivocal cases. Bone scan is sensitive but non-specific and largely superseded by MRI. CT is reserved for detailed bony assessment, particularly first rib characterisation.

Intercostal muscle injury is usually a clinical diagnosis; USS can demonstrate muscle oedema, haematoma, or fibre disruption and allows dynamic grading. Bloods are targeted: vitamin D, calcium, FBC, ferritin, thyroid function, and reproductive hormones when recurrent stress fractures or RED-S are suspected. DEXA for recurrent fractures or bone-health concerns.

Rib stress fractures follow bone-stress-injury principles. Cease the causative sport - this is the cornerstone. Paracetamol is preferred for analgesia; avoid NSAIDs because prostaglandin inhibition may impair bone healing. Maintain comfortable deep breathing with adequate analgesia. Maintain cardiovascular fitness with non-provocative cross-training (walking, lower-body cycling, core work that does not load the ribs).

Address the cause: training-load management is the most important modifiable factor. Assess rowing or bowling technique with the coach before return. RED-S screening is essential in both male and female athletes (IOC REDs CAT2). Optimise bone health (vitamin D, calcium, energy availability) and breathing pattern.

First rib stress fractures are managed similarly but with greater caution about neurovascular proximity and TOS from hypertrophic callus. Healing typically takes 4 to 8 weeks; return to sport is criteria-based, not time-based.

Intercostal muscle injuries: relative rest and activity modification. NSAIDs are acceptable for soft tissue injury (unlike fracture). Deep breathing exercises, ice or heat, and graduated return once pain-free. Most resolve within 2 to 6 weeks.

Complications: pneumothorax, haemothorax, and chest infection from splinting (mainly traumatic fractures, particularly in older adults where regional anaesthesia - serratus anterior plane or erector spinae plane blocks - is established UK practice); TOS after first-rib stress fracture; recurrent stress fractures (assess for RED-S).

Referral: routine for first rib stress fracture, recurrent fractures, or diagnostic uncertainty. Urgent for pneumothorax, neurovascular compromise, suspected pathological fracture, or suspected malignancy.

Rib stress fractures - Phase 1 (acute, 0 to 4 weeks): cease the causative sport, paracetamol analgesia (avoid NSAIDs), comfortable deep breathing, maintain fitness with non-provocative cross-training, gentle scapular and postural exercises, diaphragmatic breathing retraining if apical breathing identified, begin RED-S work-up.

Phase 2 (progressive reconditioning, 4 to 8 weeks): graduated reintroduction of trunk rotation and upper-body movement (pain-guided), progressive strengthening (erector spinae, core stabilisers, serratus anterior for rowers, obliques, rotator cuff), and gentle sport-specific patterns without resistance. Address technique with the coach before full loading.

Phase 3 (return to sport, criteria-based): graduated loading with adequate recovery. For rowers: low-resistance ergometer to on-water rowing with reduced volume to full training. Return criteria: pain-free at the fracture site with sport-specific activity, adequate trunk strength and endurance, completion of a graduated programme.

Intercostal muscle injuries follow a faster pathway: Phase 1 (0 to 2 weeks) relative rest, NSAIDs acceptable, deep breathing, ice or heat. Phase 2 (2 to 4 weeks) progressive trunk rotation and oblique reconditioning. Phase 3 (4 to 6+ weeks) sport-specific progressive rotation with criteria-based return.

• •BJSM consensus on bone stress injury - cease the causative sport, address training load and bone health, return to sport is criteria-based and not time-based alone.
• •IOC REDs CAT2 (Mountjoy et al., BJSM 2023) - the standard framework for Relative Energy Deficiency in Sport across both sexes; mandatory in any athlete with a rib stress fracture and certainly in recurrent injury.
• •BOAST 7 and UK regional anaesthesia consensus - early analgesia and regional blocks (serratus anterior plane, erector spinae plane) for traumatic rib fractures in older adults to prevent chest infection from splinting.
• •Avoid NSAIDs in active bone healing - paracetamol is preferred. NSAIDs remain appropriate for soft tissue intercostal injuries.
• •NICE CKS: Chest pain - cardiac, pulmonary, and serious causes must always be considered alongside musculoskeletal differentials.

• •Rib stress fractures are classically rowing - posterolateral ribs 4 to 8 (drive-phase bending moment).
• •A normal X-ray does NOT exclude a rib stress fracture; MRI is the preferred advanced investigation.
• •First rib stress fracture: subclavian groove site; watch for TOS from hypertrophic callus.
• •Bony rib tenderness suggests fracture; intercostal-space tenderness supports soft tissue injury.
• •Avoid NSAIDs in rib stress fractures (bone healing); NSAIDs are acceptable for intercostal strains.
• •Screen for RED-S (IOC REDs CAT2) in any athlete with a rib stress fracture - both sexes.