Calf Muscle Injury

Patients describe sudden sharp posterior leg pain (a pop, snap, or kick from behind) during explosive push-off (gastrocnemius) or during steady-state running (soleus), with immediate difficulty weight-bearing and limp. Posterior mid-calf swelling and bruising develop over 24-48 hours. Always clarify age, sport, mechanism, prior calf injury, fluoroquinolone exposure, and DVT risk factors.

Examination: focal tenderness at the site of injury (commonly the medial gastrocnemius musculotendinous junction), bruising tracking distally toward the ankle, and a palpable defect in higher-grade tears. Pain and weakness on resisted plantarflexion, pain on passive ankle dorsiflexion. Assess ankle range, neurovascular status, and contralateral comparison.

Essential rule-outs at every calf-injury consultation:

• •Simmonds-Thompson (calf squeeze) test: patient prone, knee flexed 90 degrees; squeeze the calf - absent plantarflexion suggests Achilles rupture.
• •Matles test: patient prone, actively flex both knees to 90 degrees. The intact foot rests in gentle plantarflexion; the ruptured side falls into neutral or dorsiflexion (loss of resting Achilles tension).
• •Palpate the Achilles tendon for a gap (typically 2-6 cm proximal to insertion) and test single-leg heel raise - inability supports Achilles rupture.
• •DVT risk assessment: actively consider when atypical features or risk factors are present, using the Wells score and the NICE NG158 pathway.

Differentials: acute Achilles tendon rupture (lower in the leg, positive Simmonds-Thompson, palpable gap), DVT, chronic exertional compartment syndrome (exertional pain settling with rest), ruptured Baker's cyst, medial tibial stress syndrome, tibial stress fracture, and cellulitis (erythema, warmth, constitutional symptoms).

Most calf injuries are diagnosed clinically; investigations are used selectively.

Clinical assessment alone is sufficient in most typical presentations. DVT assessment should be considered when symptoms are disproportionate, the mechanism is unclear, or VTE risk factors are present. Follow NICE NG158 with the 2-level Wells score, D-dimer, and proximal leg vein ultrasound as indicated. NICE QS201 also reminds that patients discharged with lower-limb immobilisation require VTE risk assessment.

A significant calf tear itself can produce local tenderness, calf swelling over 3 cm, and pitting oedema - all of which may artificially elevate the Wells score. D-dimer or ultrasound may be needed to confidently exclude DVT even when a muscle tear appears clinically obvious.

Achilles rupture is usually a clinical diagnosis (Simmonds-Thompson + Matles + palpable gap + heel-raise failure). Ultrasound is useful when examination is equivocal, to define rupture pattern, or to support specialist decision-making - not routinely mandatory.

MSK ultrasound (or POCUS) is useful for characterising intramuscular haematoma, differentiating gastrocnemius from plantaris or soleus, and assessing the musculotendinous junction. MRI is preferred when precise grading and location will alter management or return-to-play planning (elite athletes, diagnostic uncertainty, suspected intratendinous c injury). Plain X-ray is not usually indicated unless bony injury or stress fracture is suspected.

UK primary care follows NICE CKS Sprains and Strains principles; PEACE & LOVE is a useful BJSM sports-medicine consensus framework.

Acute phase (0-48 hours): protection, compression, elevation, and activity modification. Education about expected recovery and rehabilitation principles. Paracetamol or topical NSAID is first-line per NICE CKS; oral NSAIDs may be considered after 48 hours if needed, balancing risks and benefits. The PEACE & LOVE framework raises a theoretical concern about very early NSAIDs during the inflammatory phase - this is consensus-level rather than a firm NICE prohibition. Heel lifts (in both shoes) may reduce calf length and symptoms in the acute phase, especially in painful gastrocnemius injuries; wean as strength returns. Avoid passive stretching of the injured muscle in the acute phase. Crutches and partial weight-bearing for the first few days in grade 2 and above.

Ongoing management by BAMIC grade (broad guides only, highly variable):

• •Grade 1: early loading and graduated rehabilitation; return 1-3 weeks.
• •Grade 2: structured physiotherapy; return 4-8 weeks.
• •Grade 3: prolonged rehabilitation; return 8-12 weeks or longer.
• •Grade 4 (complete tear): most calf muscle tears are managed non-operatively. Surgical referral is reserved for selected severe cases with major functional deficit, large retracted defects, or failure of conservative rehabilitation.
• •Intratendinous (c) injuries recover more slowly than musculotendinous or myofascial injuries of the same grade.

Specific considerations: suspected Achilles rupture needs immediate equinus plaster or CAM boot with wedges and urgent same-day or next-day orthopaedic / foot and ankle assessment. Non-operative functional rehabilitation is standard UK practice in most cases per BOFAS guidance; the operative vs non-operative decision is made by the specialist team. Confirmed DVT requires anticoagulation per NICE NG158. Lower-limb immobilisation triggers VTE risk assessment per NICE QS201, particularly with additional risk factors.

Referral pathway: FCP / Advanced Practitioner physiotherapist or GP for initial triage; MSK physiotherapy or SEM clinic for grade 2-3 injuries or athletes needing structured return-to-play; urgent orthopaedic / foot and ankle referral for suspected Achilles rupture or failed conservative management of a complete tear with major functional deficit; same-day assessment for suspected DVT or compartment syndrome.

Rehabilitation is criteria-based.

Phase 1 (days 0-7): protection, relative rest, heel lifts if helpful, pain-free ankle range of motion, isometric plantarflexion.

Phase 2 (weeks 1-3): progressive concentric calf strengthening (double-leg then single-leg calf raises), ankle mobility, cycling, swimming.

Phase 3 (weeks 3-6): progressive eccentric strengthening, plyometric preparation, gentle jogging when pain-free on single-leg heel raises and hopping.

Phase 4 (weeks 6+ through return): sport-specific drills, cutting, sprinting, full eccentric loading, criteria-based return.

Return-to-sport criteria: symmetrical single-leg heel-raise endurance (within 10% of uninjured side), symmetrical single-leg hop, pain-free sprinting and cutting, sport-specific drill completion, and psychological readiness.

Secondary prevention: progressive eccentric calf strengthening, training-load management, attention to ankle dorsiflexion, and consideration of surface and footwear changes. Recurrence rates are significant, particularly in the first 6-8 weeks after return.

• •NICE CKS: Sprains and Strains - UK primary care framework, with paracetamol or topical NSAID first-line and progressive loading thereafter.
• •BJSM PEACE & LOVE consensus (Dubois & Esculier, 2020) - Modern soft-tissue injury framework emphasising protection, education, and progressive loading over rest and ice.
• •BAMIC (Pollock et al., 2014, BJSM) - The UK MRI-based muscle injury classification used in SEM and elite sport; intratendinous (c) injuries recover slowest at any given grade.
• •NICE NG158 - VTE diagnosis pathway: 2-level Wells score, D-dimer, and proximal leg vein ultrasound when DVT cannot be excluded clinically.
• •BOFAS Hyperbook: Acute Achilles Tendon Rupture - UK specialist consensus on the critical differential; non-operative functional rehabilitation is the default for most cases.

• •Medial gastrocnemius (tennis leg) is the commonest calf injury; gastrocnemius tears are ballistic with a pop, while soleus tears often occur during steady-state submaximal running without one.
• •BAMIC is the UK MRI-based grading system used in SEM and elite sport; intratendinous (c) injuries take longest to recover at any given grade.
• •Simmonds-Thompson AND Matles are both useful for Achilles rupture; rupture is usually a clinical diagnosis with ultrasound as an adjunct.
• •A severe calf tear can falsely inflate the Wells score (calf swelling over 3 cm, pitting oedema, tenderness); D-dimer or duplex US may be needed to exclude DVT even when a tear is clinically apparent.
• •Most calf muscle tears, including complete gastrocnemius tears, are managed non-operatively. Fluoroquinolones raise tendon injury and rupture risk (MHRA warning).
• •VTE risk assessment per NICE QS201 if the patient leaves in lower-limb immobilisation. Return-to-sport is criteria-based; recurrence is highest in the first 6-8 weeks.