Ligament injuries of the mid-foot can lead to long-term problems affecting our return to normal walking, let alone competitive sport. A Year on Foot at the ISEH has been monitoring the return to activity after the Welsh rugby union scrum-half sustained a severe foot injury. The trauma precluded his involvement in the 2015 World Cup and he returned only recently after more than six months’ absence for the conclusion of the Six Nations tournament and to be included in the imminent summer tour to face The All Blacks in New Zealand. A report last autumn of his foot injury, which needed surgical stabilisation and a three-month period of protection and limited weight-bearing, is characteristic for injuries of the eponymously named Lisfranc ligament in the mid-foot as Mr Michael Oddy, ISEH Consultant
Trauma & Orthopaedic Surgeon reports:
"The complex anatomical arrangement linking the flat mid-foot tarsal bones to the five metatarsal bones is maintained by staggered inter-connecting joints like the fortifications on a mediaeval castle, with a series of ligaments binding the region and maintaining the stability. This is naturally a stiff part of the foot, the rigidity of which maintains the normal arch and also locks the foot enabling it to act as a rigid-lever to allow tip-toe standing. A peculiar but normal human anatomical deficiency of the interconnection between the bases of the first and second metatarsals in this region is substituted by the oblique Lisfranc ligament fixing the second metatarsal base to the midfoot. This is vulnerable to twisting or to end-on axial loading injuries, particularly when the foot is crushed in a tip-toe position, for example when a ruck collapses in rugby union.
Lisfranc injuries represent a spectrum ranging from a mid-foot sprain, which can be managed non-operatively, to frank dislocations at the second tarso-metatarsal joint or complex fracture-dislocations of the whole mid-foot requiring surgery. The severe forms are obvious and decision making is easy as surgical stabilisation is mandatory. Subtle injuries can be difficult to identify and the relative merits of surgery may be equivocal. Lisfranc injuries are usually associated with pain, swelling and bruising of the mid-foot, particularly when the bruise is observed on the sole of the foot. The ability to bear weight is one important consideration when assessing the injury, although this often needs to be assessed in association with radiological imaging.
Plain radiographs of the foot show the bone and joint relationships with specific alignments and measurements giving evidence for a Lisfranc injury. Subtle mechanical instability may only be detected with standing X-ray investigations, if tolerated by foot pain. As the body’s weight loads and stresses the injured regions in the standing position, malalignment can be detected. More sensitive imaging such as Computerised Tomography (CT) scans can often reveal a number of small fractures in association and give detailed information about subtle joint mal-alignment. For injuries which are suspected clinically, but not demonstrated with X-rays or a CT scan, Magnetic Resonance Imaging (MRI) scanning can demonstrate sprains and tears of the ligaments themselves.
The decision to treat Lisfranc injuries with or without surgery is dependent on demonstrating whether the bone and joints are located in the correct position and whether the alignment is maintained under mechanical loading. A stable mid-foot sprain can be treated non-operatively using a plaster cast or pneumatic walker boot for approximately six weeks, although the foot may need support from an orthosis and a three to four month interval before a return to competitive sport. An unstable Lisfranc injury requires the joints to be relocated, fractures repositioned and the foot stabilised using screws and plates according to the exact configuration. The rehabilitation, as the Welsh scrum-half experienced, usually requires a six-week period in a plaster cast and then a further four to six weeks using a pneumatic walker boot. Whilst the mid-foot is stiff naturally, the very small degree of sliding and bending movement through the tarso-metatarsal region means that implant fatigue commonly occurs and so most hardware is removed approximately six months after surgery in this region, to avoid plate and screw breakage which can be associated with pain and soft-tissue irritation.
Lisfranc injuries of the mid-foot can be frustrating in terms of the duration of time taken to return to full activity, a source of litigation if the subtle sprain is missed with ensuing pain and disability, and the unavoidable risk of degenerative arthritis which may require pain-relieving injections or a formal mid-foot surgical fusion. Whilst the recovery of an international rugby union scrum-half to professional sport in this case is a triumph, the persistent association of the eponymous name of a Napoleonic surgeon with an injury which can have a miserable prognosis, could easily sway A Year on Foot at the ISEH to favour Brexit."