Foot pain after a plantar fasciotomy: An MR analysis to determine potential causes

Purpose: The purpose of this work was to determine potential causes of foot pain in patients who have had a surgical release of the plantar fascia for treatment of fasciitis. Method: We studied 17 patients (15 women, 2 men; age range 22-59 years, mea n 40 years) with foot pain after undergoing a fasciotomy. Fourteen unilater al and three bilateral procedures accounted for the 20 ankles evaluated. Me an duration after surgery was 22 months (range 3-53 months). Each patient w as instructed to localize the pain to a region of the foot; classify the pa in as new onset, persistent, or recurrent; and characterize it as to the ac tion that produced the greatest pain. T1-weighted sagittal and dual-echo T2 -weighted images in the sagittal, coronal, and axial planes were obtained i n a 1.5 T magnet. The MR studies ware evaluated for abnormalities of the pl antar fascia, perifascial soft tissues, tendons, and osseous structures. Results: The plantar fascia appeared thick in all ankles (mean 8.0 mm, rang e 6-12 mm). A total of 25 symptomatic sites were assessed. An acute plantar fascia rupture explained plantar symptoms in two feet. In another 16 feet (12 with plantar heel pain and 4 with nonspecific heel pain), 6 had documen tation of acute plantar fasciitis and 9 demonstrated perifascial edema. Of the latter nine feet, live demonstrated abnormalities of the posterior tibi alis, peroneus longus, and peroneus brevis tendons. The pain localized to t he medial arch in six feet; five feet had abnormalities of the posterior ti bialis tendon and one foot demonstrated edema in the flexor digitorum brevi s muscle. The pain localized to the lateral midfoot in one foot, which had a cuboid stress fracture. Conclusion: The cause of foot pain in patients who had a plantar fasciotomy appeared to be multifactorial. Three likely causes of pain were identified : persistent or recurrent acute plantar fasciitis, pathology related to arc h instability, and structural failure from overload.