Compartment pressures, limb length changes and the ideal spherical shape: a case report and in vitro study

Changes in compartment pressures have been noted during traction, reduction, and intramedullary fixation of fractures. Changes in limb length and compartment volumes are suspected contributing factors. Pressure and volume changes are known to be related in animal models. If an acute increase in limb length can adversely affect compartment pressures, reversal or delay of such an increase in length may be of value in the treatment and prevention of compartment syndromes.

A clinical example is presented in which a documented anterior compartment syndrome was successfully treated by deliberate loss of fracture reduction, without fasciotomy. Fracture reduction was later restored when swelling subsided. Anterior compartment pressures were recorded in response to limb length changes in osteotomized cadaver limbs stabilized with external fixation.

The pressure in the anterior compartment varies directly with acute changes in the length of the leg, in an experimental model. Mathematical analysis indicates that available volume within a compartment varies inversely with acute changes in its length.

Fracture reduction that restores the length of an acutely injured extremity may increase pressure in the compartments by decreasing available volume. Deliberate loss of reduction can decrease pressure in the compartments, offering a potential alternative to fasciotomy in the care of compartment syndrome in cautiously selected, monitored patients. Early stabilization without reduction, followed by delayed reduction, may be preferable during treatment of fractures prone to compartment syndrome. Decreased available compartment volume may contribute to compartment syndrome after distraction with intramedullary rods or skeletal traction.