What is the treatment for a chronic nonunited avulsion fracture of the ischial tuberosity at the hamstring tendon origin attachment?

Treatment of Chronic Nonunited Avulsion Fracture of the Ischial Tuberosity

Surgical repair with open excision of the bony fragment followed by suture anchor fixation of the hamstring tendons is the recommended treatment for chronic nonunited avulsion fractures of the ischial tuberosity that cause pain and functional limitations. 1

Diagnostic Evaluation

Before proceeding with treatment, proper evaluation is necessary:

1. Imaging studies:

   • MRI is the preferred imaging modality to evaluate the extent of the injury, associated soft tissue damage, and confirm nonunion 2
   • Plain radiography to assess fragment displacement and bone quality 2

2. Clinical assessment:

   • Pain localized to the ischial area, especially during activities
   • Weakness in hamstring muscles
   • Functional limitations in sports or daily activities

Treatment Algorithm

Conservative Management

Conservative management is typically unsuccessful for chronic nonunited avulsion fractures with significant displacement, as evidenced by multiple case reports 1, 3, 4, 5. These cases often progress to:

• Persistent pain
• Hamstring weakness
• Functional limitations
• Inability to return to pre-injury activity levels

Surgical Management

Surgical intervention is indicated when:

• Fragment displacement is substantial (>2 cm)
• Patient experiences pain and functional limitations
• Conservative treatment has failed
• Patient desires to return to high-level activities

Surgical Techniques

Several surgical approaches have demonstrated success:

1. Suture Anchor Fixation with Fragment Excision 1:

   • Open excision of the bony fragment
   • Repair of proximal hamstring tendons using suture anchors
   • Particularly effective for chronic cases with large fragments

2. Suture Bridge Technique 3:

   • Uses biodegradable suture anchors in a bridge configuration
   • Provides secure fixation
   • Enables early return to activities

3. Posterior Column Screw Fixation 4:

   • Through a subgluteal approach
   • Muscle-sparing technique
   • Effective for nonunions without the need for bone grafting

4. Open Reduction and Internal Fixation 5:

   • Traditional approach for acute and chronic cases
   • Allows for anatomic reduction and stable fixation
   • Has enabled return to high-level athletic performance

Rehabilitation Protocol

Following surgical repair, a structured rehabilitation program is essential:

1. Early Phase (0-6 weeks):

   • Relative rest and protected weight-bearing
   • Gentle range of motion exercises
   • Cryotherapy for pain management 2

2. Intermediate Phase (6-12 weeks):

   • Progressive strengthening exercises
   • Emphasis on eccentric hamstring strengthening 2
   • Gradual return to functional activities

3. Advanced Phase (3-6 months):

   • Sport-specific training
   • Balance and proprioceptive exercises
   • Return to pre-injury activity level based on strength and functional testing

Expected Outcomes

With appropriate surgical management and rehabilitation:

• Pain relief
• Restoration of hamstring strength
• Return to pre-injury activity levels, including high-level athletics 1, 6, 5
• Radiographic healing typically observed by 6 months post-surgery 4

Common Pitfalls and Caveats

1. Delayed Diagnosis:

   • These injuries are often misdiagnosed as hamstring strains
   • Early recognition is crucial for optimal outcomes 6

2. Inadequate Fixation:

   • Achieving sufficient fixation strength can be challenging
   • Modern techniques like suture bridge or multiple anchors provide more secure fixation 3

3. Premature Return to Activities:

   • Gradual progression is necessary to prevent re-injury
   • Complete healing should be confirmed before full return to sports

4. Nerve Injury:

   • The sciatic nerve is at risk during surgical approaches to this area
   • Careful surgical technique is required to avoid iatrogenic nerve injury 2

In conclusion, while most avulsion fractures can be treated conservatively, chronic nonunited avulsion fractures of the ischial tuberosity with significant displacement and functional limitations require surgical intervention. The evidence supports that surgical repair, even when delayed, can result in excellent outcomes and return to full function.