What is the initial work-up and treatment for a hamstring injury?

Hamstring Injury Work-Up

Initial Clinical Assessment

Begin with a focused clinical examination looking for sharp or stabbing posterior thigh pain that is well-localized, with tenderness corresponding to the pain location, and assess for visible swelling, ecchymosis, or asymmetry. 1

Key History Elements

• Mechanism of injury: Typically occurs during forceful eccentric contraction, most commonly while sprinting or running 2
• Pain characteristics: Sharp or stabbing pain in the posterior thigh that increases with activity and may temporarily subside after warm-up 1
• Functional limitations: Assess ability to bear weight and perform activities 1
• Previous hamstring injuries: Critical prognostic factor for recurrence risk 3

Physical Examination Findings

• Palpation: Well-localized tenderness in the posterior thigh corresponding to the area of pain during activity 1
• Functional testing: Reproduce pain with maneuvers that simulate hamstring loading (resisted knee flexion, passive hip flexion with knee extension) 1
• Visual inspection: Look for swelling, ecchymosis, and asymmetry compared to the contralateral side 1

Imaging Strategy

Obtain MRI without contrast as the definitive imaging study when imaging is warranted, as it has near-perfect detection rates and can classify injury location, extent, and identify complete ruptures or proximal avulsions. 1

When to Image

• Immediate imaging indications: Suspected complete rupture, proximal avulsion, or inability to bear weight 1
• MRI advantages: 100% detection rate for proximal hamstring avulsions, can classify partial versus complete tears, identifies chronicity and extent of injury 1
• Ultrasound limitations: Only 58.3% detection rate for proximal avulsions compared to MRI's 100%, insufficient evidence to support as primary diagnostic tool 1

Critical Differential Diagnoses to Exclude

• Sciatic nerve irritation or compression 1
• Hip arthritis 1
• Chronic compartment syndrome 1

Injury Grading and Prognosis

Healing Timeframes by Severity

• Grade 1-2 (mild to moderate): Complete healing typically occurs within 50 days 4
• Grade 3-5 (severe): Complete healing takes approximately 75 days 4
• General timeline: 84% of patients show complete healing by 2-2.5 months regardless of severity 4
• Return to sport: Full return typically occurs between 6-12 weeks depending on severity 4

Initial Treatment Protocol

Implement relative rest (not complete immobilization), apply ice through a wet towel for 10-minute periods for acute pain relief, and initiate NSAIDs for pain management while avoiding complete immobilization to prevent atrophy. 4

Immediate Management (First 48-72 Hours)

• Cryotherapy: Apply ice through a wet towel for 10-minute periods 4
• Relative rest: Avoid activities that reproduce pain but maintain some mobility to prevent atrophy 4
• NSAIDs: Effective for pain relief and may reduce swelling; topical formulations eliminate gastrointestinal hemorrhage risk 4
• Avoid complete immobilization: Prolonged immobilization leads to muscle atrophy and loss of strength 4

Progressive Rehabilitation

• Eccentric strengthening exercises: Proven beneficial with strong evidence, shown to reverse degenerative changes 4, 1
• Neuromuscular control exercises: Component of evidence-based non-operative management 1
• Gradual activity progression: Increase activity while monitoring pain response 4

Surgical Indications

Refer for surgical evaluation if MRI demonstrates a 2-tendon injury with >2 cm retraction, any 3-tendon injury, complete rupture with loss of function, or failure to improve after 6 months of conservative management. 2

Specific Surgical Criteria

• Acute proximal injuries: 2-tendon injuries with >2 cm retraction or any 3-tendon injury 1, 2
• Complete ruptures: With documented loss of function 2
• Failed conservative management: No improvement after 6 months of appropriate rehabilitation 1, 2
• Timing: Acute repair preferred over delayed repair for better functional outcomes and strength recovery 1

Return-to-Sport Criteria

Clear for return to sport only after functional hop testing, objective isokinetic testing showing adequate hamstring-to-quadriceps ratio, resolution of hamstring tenderness, and restoration of flexibility and strength. 4

Objective Assessment Parameters

• Functional hop testing: One factor to consider before clearance 4
• Isokinetic testing: Assess hamstring-to-quadriceps ratio 4
• Clinical monitoring: Hamstring tenderness, flexibility, and strength 3
• Timeline: Minimum 4-6 weeks before returning to sport activities, with most requiring 6-12 weeks 4

Critical Pitfalls to Avoid

• Premature return to sport: High risk of recurrence if rehabilitation incomplete; previous injury is the most valuable predictor of recurrent injury 3
• Complete immobilization: Leads to rapid muscle atrophy and loss of strength and extensibility 4
• Relying on ultrasound alone: Misses 42% of proximal avulsions that MRI would detect 1
• Missing complete ruptures: Require immediate surgical evaluation, not conservative management 2