Session II Foot and Ankle

*Clinical and CT Correlation of Calcaneal Fractures - A Two Year Follow-Up Study

R.E. Buckley, MD, Philippe Aubin, MD, Doug Connell, MD, Kevin Hildebrand, MD

University of Calgary, Calgary, Alberta, CANADA

Purpose: To determine the natural history of displaced intra-articular calcaneal fractures, to determine which features are associated with late post-traumatic arthritic changes on CT, and to correlate late CT changes with patient outcomes.

Methods: This study used a cohort of patients from a large randomized prospective multicentre calcaneal fracture study presenting for two year followup. Displaced intra-articular calcaneal fractures treated nonoperatively underwent initial and two year CT scanning, while those treated operatively underwent initial, postoperative and two year CT scanning. From the initial CT scans, Sander's classification, articular step or gap, and amount of peroneal displacement were all recorded. Surgically treated patients had the same features and presence of intra-articular screws recorded from the postoperative CT scans. All of these measures were again recorded on the two year CT scan as was the severity of post-traumatic arthritis or the presence of intra-articular gas. Patients subjective outcomes were obtained using a validated visual analog scale (VAS) and the SF-36.

Results: Fifty-nine intra-articular fractures in fifty-three patients made up the cohort; thirty-one (53%) were treated surgically while twenty-eight (47%) were treated conservatively. Four of the thirty-one surgical patients (13%) were found to have a screw into the calcaneocuboid joint and two into the subtalar joint. Conservatively treated patients did not show improvement in subtalar articular step deformity over two years. The improvement in subtalar incongruity was more impressive in those treated surgically, with change noted postoperatively (p=0.03), and further improvement noted by the two year scan (p=0.005). No significant link was found between the Sander's class., peroneal tendon shift or subtalar step and the presence of late degenerative changes. However, the articular incongruity was significantly associated with post-traumatic arthritis in the conservative group (p=0.04). Presence of an intra-articular screw was associated with degenerative arthritis (p=0.005). No statistically significant links were found between the initial Sander's class., initial joint incongruity, or two year degenerative arthritis and the patient outcomes as measured by VAS score or the SF-36.

Discussion: As the treatment of displaced intra-articular calcaneal fractures is most controversial, a larger prospective study provides us with an excellent chance to follow the natural history of calcaneal fractures treated operatively and nonoperatively and with associated CT examination. Classification systems to date have not proven to be prognostic. This study shows that the CT-generated classification, the Sander's classification, is not prognostic as there is no link between classification and patient outcomes as measured by the validated VAS score or the SF-36. Operatively treated patients showed marked improvement in subtalar articular step deformity with remodeling of the joint surface. This may explain operatively treated patient ability to significantly improve with time. There was a trend that the amount of intra-articular congruity was significantly associated with post-traumatic arthritis (as viewed by CT) in conservatively treated calcaneal fractures. However, there was no link between the amount of incongruity and patient outcomes.

Conclusions: 1. Present classification systems are not prognostic; 2. Subtalar incongruity appears to change with time as viewed by CT; 3. Articular incongruity was associated with post-traumatic arthritis as viewed by CT; 4. There were no links between joint incongruity, two year degenerative arthritis and patient outcomes as measured by visual analog score or SF -36.