A 35-year-old male presents 8 weeks after a scaphoid waist fracture that was treated with immobilization. He now has persistent wrist pain and clicking. Repeat radiographs show no bridging callus across the fracture site. What is the most appropriate next step in management?

Explanation

## Clinical Context At 8 weeks post-immobilization with persistent pain and no radiographic evidence of bridging callus, this patient has a **delayed union or impending nonunion**. The waist location carries the highest nonunion risk due to tenuous blood supply. Operative intervention is now indicated. ## Nonunion Risk Stratification in Scaphoid Fractures | Risk Factor | Impact | Nonunion Rate | |---|---|---| | **Fracture location** | Proximal > waist > distal | Proximal: 10–15%; Waist: 5–10%; Distal: <5% | | **Displacement** | >2 mm increases risk | 2–3× higher | | **Associated injuries** | Ligament damage, comminution | Increased | | **Smoking, poor compliance** | Impaired healing | Increased | | **Time to diagnosis** | Delayed treatment | Increased | ## Management Algorithm for Scaphoid Nonunion/Delayed Union ```mermaid flowchart TD A[8+ weeks post-immobilization]:::outcome --> B{Bridging callus on X-ray?}:::decision B -->|Yes| C[Continue immobilization]:::action B -->|No| D[Obtain CT scan]:::action D --> E{Assess: Fracture pattern, vascularity, displacement}:::outcome E --> F{Nonunion confirmed?}:::decision F -->|Yes| G[Operative fixation: ORIF ± bone graft]:::action F -->|No| H[Continue immobilization, consider advanced imaging]:::action G --> I[Screw fixation ± vascularized bone graft if AVN]:::action ``` ## Key Point: **CT scan is the gold standard for assessing scaphoid nonunion.** It provides: (1) fracture geometry and displacement, (2) assessment of fracture surfaces (sclerosis, gap), (3) evaluation of proximal pole vascularity (indirectly), and (4) guidance for operative planning. ## High-Yield Facts: - **Delayed union:** No bridging callus at 8–12 weeks but fracture surfaces remain viable and in contact. - **Nonunion:** No bridging callus after 12–16 weeks; fracture surfaces may show sclerosis, gap, or cystic changes. - **Waist fractures** have the highest nonunion risk (5–10%) due to retrograde blood supply and limited collaterals. - **Operative fixation** (percutaneous screw fixation ± bone graft) is indicated for confirmed nonunion or impending nonunion with no bridging callus at 8+ weeks. - **Vascularized bone graft** is added if there is evidence of avascular necrosis of the proximal pole (seen on CT as sclerosis, cystic changes, or on MRI as signal changes). ## Clinical Pearl: **Persistent pain + no callus at 8 weeks = CT scan and prepare for surgery.** Waiting longer increases the risk of irreversible avascular necrosis and chronic wrist dysfunction. Early operative intervention has better outcomes than delayed intervention. ## Operative Options for Nonunion | Technique | Indication | Graft Type | |---|---|---| | **Percutaneous screw fixation alone** | Nonunion with viable fracture surfaces, no AVN | No graft | | **ORIF + cancellous bone graft** | Nonunion with gap or comminution | Autograft (iliac crest) | | **ORIF + vascularized bone graft** | Nonunion with AVN of proximal pole | Vascularized graft (1,2-ICSRA, medial femoral condyle) | | **Proximal row carpectomy (PRC)** | Salvage for chronic nonunion with AVN and arthritis | N/A | ## Tip: In the exam, when you see "8+ weeks post-immobilization + no callus + persistent pain," think **CT scan → operative fixation**. MRI is not the next step; CT is. Arthroscopy is not indicated for nonunion assessment.