Scaphoid Fractures - epidemiology, diagnosis and treatment.

Abstract The scaphoid is the most commonly fractured carpal bone. The diagnosis is difficult and untreated the
long-term results are poor. Approximately 10% do not unite even if they are treated properly. The aim of this thesis
was to study scaphoid fracture epidemiology, diagnosis and treatment. During a four-year period (2004-03-01 to
2008-02-28) all patients attending the Emergency Department at Skåne University Hospital in Malmö, due to
posttraumatic radial sided wrist pain, were invited to participate in a scaphoid fracture study. The basis for this thesis
consists of the 526 patients (531 wrists) who accepted to participate. First we assessed the diagnostic performance
of radiographs and CT with MRI as the reference standard. In paediatric patients (<18 years) fracture patterns were
studied in relation to skeletal maturity. Using arthroscopy we aimed at identifying factors, which could contribute
to prolonged union or non-union of scaphoid fractures. Finally, we evaluated time-to-union of scaphoid waist
fractures treated conservatively or by arthroscopy-assisted surgery. In the two diagnostic studies on adults and
paediatric patients (paper I-II) 390 wrists were enrolled for MRI investigation. We were able to show that
radiographs and CT scans are less sensitive in diagnosing carpal fractures compared to MRI. In particular
radiographs in paediatric patients had a poor sensitivity when diagnosing carpal fractures; however, CT had a good
sensitivity in finding scaphoid fractures regardless of patient age. We found more concomitant fractures than
previously described, and the most common carpal fracture combination was that of the scaphoid and the capitate.
Skeletal immature patients had a higher proportion of distal scaphoid fractures compared to the skeletal mature. In
the descriptive study using arthroscopy (paper III) 41 scaphoid waist fractures were included. We found, that
scapholunate ligament injuries were common with a complete rupture in 24% of the patients. Paper IV is a joint
venture with Harvard Medical School, Boston, USA. In 58 scaphoid fractures we were able to show, that
radiographic fracture comminution was strongly correlated to displacement and instability as judged by arthroscopy.
Scapholunate ligament injuries and fracture comminution may be of importance when deciding on treatment of
scaphoid fractures. Time-to-union based on CT was assessed in 65 scaphoid waist fractures in paper V. Of the nonor
minimally-displaced fractures 90% united after six weeks of conservative treatment. In a randomized subgroup
of non-displaced fractures we were not able to show any difference in time-to-union between conservatively and
surgically treated patients. The present thesis shows, that MRI is superior in diagnosing carpal fractures in adults
and children. Furthermore we found, that concomitant carpal fractures and ligament injuries are common in
patients with scaphoid fractures. Radial fracture comminution is strongly correlated to fracture instability. Finally
we recognized, that non- or minimally-displaced scaphoid waist fractures are best treated in a cast.