Follow-Up CT After Eden-Hybinette Procedure for Shoulder Dislocation
CT without IV contrast should be obtained to assess graft position, graft healing/incorporation, graft resorption, hardware positioning, and any complications such as graft protrusion or periprosthetic fracture.
Essential CT Evaluation Components
Graft Assessment
- Graft positioning: Evaluate whether the bone block is optimally positioned at the anteroinferior glenoid rim without articular protrusion, as protrusion is associated with development of osteoarthritis 1
- Graft healing and incorporation: Assess osseous integration of the iliac crest autograft to the native glenoid, with healing rates of 92.3% reported at minimum 2-year follow-up 2
- Graft resorption: Quantify any absorption of the bone graft, though complete resorption is rare with proper technique 3
Hardware Evaluation
- Fixation device position: Verify proper placement of the double-pair button fixation system or screws used to secure the graft 2, 3
- Hardware complications: Identify any hardware breakage, migration, or loosening that could compromise stability 4
Bone Stock and Complications
- Glenoid bone restoration: Measure restoration of glenoid width and confirm correction of the preoperative bone deficiency 3
- Periprosthetic fractures: Rule out fractures of the glenoid or scapula, which can occur postoperatively 5
- Component alignment: Assess for any changes in graft alignment over time that might indicate failure 5
Technical CT Protocol
Imaging Parameters
- CT without IV contrast is the appropriate modality - contrast adds cost and radiation exposure without diagnostic benefit for evaluating bone graft incorporation and positioning 5, 6
- Metal artifact reduction protocols should be employed if metallic fixation devices are present, as newer software significantly improves visualization around hardware 5
- Timing: Initial CT is typically performed at 6 weeks postoperatively to evaluate early graft integration 7, with subsequent imaging at clinical follow-up intervals
Why CT Is Superior to Other Modalities
Advantages Over Plain Radiographs
- CT provides superior assessment of graft positioning, healing, and three-dimensional bone stock evaluation that cannot be adequately assessed on plain films 5
- CT better demonstrates periprosthetic lucency, osteolysis, hardware malposition, and component migration compared to radiographs 5
Role of MRI
- MRI is NOT the primary modality for bone graft evaluation after Eden-Hybinette procedure
- MRI without contrast should only be added if soft tissue complications are suspected, such as rotator cuff tears or subscapularis tendon injury from the surgical approach 5, 8
Critical Pitfalls to Avoid
Imaging Errors
- Do not order CT with IV contrast - it provides no additional diagnostic information for bone graft assessment and unnecessarily increases cost and radiation 5, 6
- Do not rely solely on radiographs - they are insufficient for comprehensive evaluation of graft incorporation and positioning 5
Clinical Interpretation
- Articular protrusion must be identified - graft protrusion into the joint space is the primary cause of post-procedure osteoarthritis development 1
- Distinguish normal postoperative bone remodeling from complications - increased bone activity can persist up to 2 years after surgery and should not be misinterpreted as loosening or infection 5
- Evaluate graft positioning in multiple planes - suboptimal positioning may not be apparent on single views and requires multiplanar CT reconstruction 5