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Hypothesis:

Proximal pole scaphoid fractures are less common than waist fractures, however when they do occur, successful management can be difficult.  Although a significant amount of literature exists regarding treatment of proximal pole nonunions, there are few studies evaluating factors affecting the outcome of open reduction and internal fixation of acute proximal pole scaphoid fractures.  We hypothesize that early union rates will decrease with delays in surgical fixation, greater initial displacement and higher energy mechanisms of injury.

Methods:

A retrospective review was conducted of all patients undergoing open reduction, internal fixation (ORIF) of acute proximal pole scaphoid fractures at our institution over a nineteen year period.  To qualify for inclusion, patients must have undergone surgical treatment within 4 weeks of their date of injury.  A review of the clinical charts as well as radiographic analysis was undertaken. The mechanism of injury, patient demographics, timing of surgery, initial fracture displacement, type of fixation, smoking status and lunate morphology were recorded.   Functional outcome measures were recorded when available.  Univariate analysis using Kaplan-Meier survival curves was performed.

Results:

Following surgical reduction a total of 13 of 27 patients (48%) showed evidence of more than 50% fracture union at 14 weeks post-injury.  69% of non-displaced fractures healed within 14 weeks, while only 29% of displaced fractures healed within the first 14 weeks (p=0.058).  73% of fractures stemming from low energy mechanisms healed, while only 17% of high energy mechanisms healed within 14 weeks (p=0.003).  Delay in ORIF did not appear to influence rate of union (p=0.27).  At final follow up, average grip strength was 23 kg, compared to 42 kg on the contralateral uninjured side.  Wrist flexion and extension data on the injured side averaged 36 and 44 degrees respectively, while wrist radial and ulnar deviation averaged 13 and 25 degrees, respectively.  Of the 24 fractures that eventually went on to union, 22 of these (92%) achieved full or partial union within 24 weeks of surgery.

Summary:

- Initial displacement and mechanism of proximal pole scaphoid injuries have the most significant effects on early rates of union.

- Delay in ORIF of up to 28 days did not affect the rate of initial union.  Despite this, the authors recommend early surgical fixation of these fractures to prevent further displacement. 

- Patients with widely displaced fractures or those involved in high energy mechanisms should be counseled regarding the prolonged time for fracture union.