A Closer Look At Lateral Talar Process Fractures With Snowboarding Injuries
Type A: extraarticular ligamentous avulsion
Type B1: simple chip fracture of the posterior talocalcaneal (TC) joint surface
Type B2: comminuted chip fracture of the posterior talocalcaneal joint surface
B1 and B2: do not involve the talofibular joint surface
Type C1: single large complete fragment fracture
Type C2: comminuted fracture involving both surfaces of the posterior talocalcaneal and talofibular joints
C1 and C2 both involve the TC and the talofibular joint surfaces.
Funk, et al., indicated that by using this classification, one can make better decisions in treatment planning for LTP fractures.2 They suggested that type A and B1 fractures respond well to conservative casting methodology while types B2, C1 and C2 may respond better to surgical intervention.
What You Should Know About Treatment
Surgical texts describe treatment regimens for LTP fractures in terms of the Hawkins classification. Mann and Coughlin indicate that size, degree of comminution and displacement of the LTP are critical in determining the appropriate treatment plan. 4 Historically, Hawkins and Shelton recommend initial closed reduction of all fractures of the lateral talar process and subsequent non-weightbearing with a below knee cast for four weeks, and partial weightbearing for an additional two weeks.11,20
Further, Mann and Mukherjee, et al., state that a single large fragment requires accurate reduction by ORIF to restore and maintain STJ congruity while one would treat comminuted fractures by removing the fragments.4,21 Funk, et al., describe surgical intervention as acceptable and necessary when the fragments are large (>1 cm), and significantly displaced (>2 mm) or comminuted.2
A recent study by von Knoch, et al., reported treatment outcomes of 23 LTP fractures from 1995 to 2001 with a mean follow-up of 3.5 years.10 Treatment was based on fracture type, the degree of displacement of the fracture, and the presence or absence of associated injuries.
Utilizing Hawkins classification type I, II and III fractures that were displaced less than 1 mm without any other associated injuries (30 percent), researchers provided non-operative treatment. The non-operative regimen included six weeks of Aircast immobilization with partial weightbearing (15 kg) until there was radiographic evidence of healing, and then patients could begin full weightbearing.
The researchers performed open reduction on the majority of individuals (70 percent) with a severely displaced or comminuted Hawkins type II or III LTP fracture. When it came to fragmentary injuries, the surgeons applied fixation in a craniomedial direction through the talus while they removed comminuted fragments.
The researchers used the American Orthopaedic Foot and Ankle Society (AOFAS) hindfoot (ankle-hindfoot) scoring to measure postoperative pain, function and alignment to determine the degree of success. Non-operative treatment and open reduction of fractures both had an average mean score of 94. Individual scoring is worth noting because alignment was a perfect 10 out of 10 for both conservative and invasive modalities. The average pain score was 36 out of 40 and the average function score was 48 out of 50.
However, what researchers deduced from this was that approximately 45 percent presented with mild to moderate degenerative changes (subchondral lesions) of the STJ. Most of the degenerative changes occurred in the surgically treated patients with the more severe injury.10
A similar study by Valderrabano, et al., reviewed 26 patients from 1999 to 2001 for sustained LTP fractures. 16 Researchers obtained appropriate radiographic views due to a high suspicion of LTP fracture. Eighty percent of all reported cases were classified as type II fractures, type I fractures accounted for 15 percent and type III fractures accounted for 5 percent, according to the Bladin-McCrory injury classification system.
Again, patients underwent treatment according to type and severity. Type I and III cases were non-operative. In regard to patients with type II injuries, researchers used non-operative treatment in two cases and employed open reduction in 14 cases. Each type had only one that required revision.