Purpose

This study compares outcomes in patients with complete congenital fibula absence treated with an amputation protocol to those using an extension prosthesis.

CECS is an exercised induced condition that causes pain, typically in the lower limbs, and is relieved by rest. It is often seen in military personnel significantly restricting their duties. Conservative treatment is rarely successful and patients often require surgical decompression by fasciotomy or fasciectomy.

All IMP (intramuscular pressure) tests (n=286) carried out between December 2007 and October 2010 on patients with suspected CECS in the anterior compartment of the lower leg were reviewed. The treatment and outcomes of those referred for surgery were analysed. Pre- and post-surgery military medical grading for leg function was extracted from the medical records system. Independent t-tests compared differences between patients that had surgery or did not. The Wilcoxon signed-rank test compared grades before and after surgery.

According to the diagnostic criterion, 80% of patients undergoing IMP testing had CECS. Of these, 179 (68%) patients underwent surgery, 17 (9%) of these were for recurrent symptoms. Almost all decompressions were bilateral (95%). The majority of operations (121) were fasciectomies of the anterior compartment only and were performed by 2 surgeons. The remaining operations (58) were performed by 6 surgeons and were fasciotomies of both anterior and lateral compartments. The mean time from testing to surgery was 24 (median 11) weeks. There were 23 (13%) complications other than recurrence including 16 wound infections, 6 seromas and 1 haematoma. Pre- and post-surgery grading was available for 67% of patients. These patients had significantly better leg function after surgery (Z=−3.67, p<0.001). Of these, 47% improved, 38% showed no improvement and 15% had a poorer outcome had. Those who had a fasciectomy were significantly more likely to improve than those who had a fasciotomy (p=0.023, rho=−1.96).

Our results demonstrate that patients generally improve lower limb function following surgical decompression. However, 53% showed no improvement or deteriorated in their medical grading. In addition, there is a high diagnosis rate for CECS following IMP measurement. This may reflect the poor validity of the diagnostic criterion or this could be due to good clinical selection for testing. Furthermore, fasciectomy shows a greater correlation with improved outcome than fasciotomy. There is a need to develop more accurate diagnostic criteria and to evaluate the benefits of standardising surgical technique.

Nomograms derived from mathematical analysis indicate that the level of malunion is the most important determinant of changes in the moment arm of the knee, the plane of the ankle and alterations in limb length. Testing in five patients undergoing reconstruction showed a mean error of postoperative limb length of 2.2 mm (sd 0.8 mm), knee moment arm of 4.7 mm (sd 3.3 mm) and ankle angle of 2.6° (sd 2.3°). These nomograms provide the information required when assessing whether a particular degree of angulation may be accepted.