"Minor" fractures
Most cuboid fractures are minor avulsions or marginal compression fractures associated with midtarsal sprains. Even these injuries need to be assessed carefully, because a few represent much more serious occult midtarsal dislocations. The mechanism of injury and the degree of swelling and tenderness should give clues. Provided the injury is stable it can probably be managed functionally with the RICE regime.
Stress fractures
The cuboid may rarely be the site of stress fractures in athletes or osteopenic patients. These tend to present as obscure lateral foot pain and may require isotope scanning or MRI for diagnosis. A few case reports recommend a short period of casting, although it is possible that functional treatment might be adequate.
Compression ("nutcracker") fractures
More serious are compression injuries between the calcaneum and metatarsals ("nutcracker fractures") due to forced valgus or axial compression of the forefoot, and usually associated with midtarsal dislocation (Main and Jowett 1975), fracture of the navicular (Sangeorzan 1989) or fracture of the calcaneum. They may be difficult to spot on plain films and CT may be necessary to show the damage adequately.
Weber (2002) described two main injury patterns which may be combined:
- impaction of the distal articular surface by the 4th and 5th metatarsals (11/12 patients)
- burst fracture of the body of the cuboid (5/12 patients)
Significant impaction will shorten the lateral column of the foot (5/12 patients in Weber's study).
Sangeorzan (1990) and Weber (2002) recommend ORIF with bone grafting as required for shortened fractures or those with significant articular damage. A spanning external fixator can be useful to restore length and may be left on to protect fixation if necessary. Small plates are often useful to buttress the reconstruction and bone graft can often be obtained locally. Weber recommended 6 weeks NWB and 6 weeks PWB. The mean AOFAS midfoot score in Weber's series was 86; 9/12 patients had some residual disability, mainly die to medial column stiffness or pain. Three had symptomatic OA of the calcaneocuboid or TMT joints.
References
- Main BJ, Jowett RL. Injuries of the midtarsal joint. JBJS 1975;57B:89-97
- Sangeorzan BJ et al. Displaced intra-articular fractures of the tarsal navicular. JBJS 1989;71A:1504-10
- Sangeorzan BJ, Swiontowski MF. Displaced fractures of the cuboid. JBJS 1990;72B:376-8
- Weber M, Locher S. Reconstruction of the cuboid in compression fractures: short to midterm results in 12 patients. FAI 2002;23:1008-13