Playing fields baked hard by the late summer sun can place the foot at significant injury risk in the return to training and competitive sports in late August and September. Hyperextension injuries, or forced upward movement of the big toe metatarso-phalangeal joint can lead to a variety of injuries which have broadly been called a turf toe. Originally described as varying degrees of a joint sprain in American Footballers playing on Astroturf, the injury is now more widely recognised in the UK in field sports, but can also occur after trips and falls running, kicking sports or urban activities like parkour. Mr Michael Oddy, ISEH Consultant Trauma & Orthopaedic Surgeon reports:
"The main big toe hallux metatarso-phalangeal joint is a complex articulation between the first metatarsal and the proximal phalanx toe bone. The capsule, or sack binding the bones of the joint together, is reinforced on the underside as the thickened plantar plate and supported by a sling of flexor tendons in which are located two small sesamoid bones. The sesamoid bones protect the metatarsal head but their main mechanical function is probably to improve the pulley-like action of the short flexor hallucis brevis tendons.
True turf toe injuries from axial loading of the joint in an extended position lie on a spectrum of big toe hallux injuries presenting with varying degrees of pain, swelling and bruising and the possibility of long-term problems. In the extreme form this can be associated with a traumatic joint dislocation with widespread soft tissue, bone and cartilage injury. Minor sprains can be more subtle and it may be that associated injuries to the sesamoid complex are the dominant clinical problem and can be far more challenging to treat. Sesamoid bones can themselves be fractured acutely, develop stress fractures, fragment and separate under avascular necrosis related to a disruption of local blood supply, of be painful as sesamoiditis without direct injury or clear pathology.
A plain X-ray of the joint is important to identify obvious fractures or malalignment. The sesamoid position can also demonstrate possible patterns of soft tissue injury, with separation or migration highlighting plantar plate or flexor tendon disruption. Computerised tomography (CT) delineates bony injury in more detail or a Magnetic Resonance Imaging (MRI) scan can identify the extent of the soft tissue injury and associated cartilage damage or loose bodies in the joint.
Mild soft tissue injuries require basic sports injury first aid with rest, ice and elevation. A short pneumatic walker boot or surgical sandal with a rocker sole can aid mobility whilst protecting the joint. If the swelling is not extreme then joint protection with taping can be usefully employed and thereafter a graded return to activity. More severe injuries may need protection in the longer term with stiffer soled shoes and a bespoke insole orthosis with a rigid extension under the big toe joint to protect against forced upward extension of the joint. Surgery is uncommon acutely unless there is a traumatic joint dislocation, acute development of a bunion or claw toe deformity, loose fragments in the joint, or a wide separation of the sesamoids and complete plantar plate rupture. Rehabilitation is important post operation to work on range of movement and prevent stiffness common after this injury. A return to sport would be unlikely before three to four months post operation but a weakness in push-off strength might persist and affect gait, speed and strength.
The later sequelae of a turf toe, particularly with repeated injuries is a claw toe deformity with arthritis. The clawing of the toe reflects dysfunction of the flexor hallucis brevis and sesamoid complex allowing the toe to rest in extension and then be deformed by the longus tendon. A clawed toe position increases pressure on the sole of the foot under the sesamoids and over the big toe second joint between the phalanges leading to hard skin callosities. Arthritis as a result of cartilage damage can develop without deformity and can be symptomatic from joint pain and stiffness, or from prominent bony osteophyte spurs. Image-guided injections of corticosteroid can be effective for pain relief before considering surgical treatment. Operative options can involve joint debulking as a cheilectomy, biological resurfacing with capsule interposition, joint replacement or fusion depending on the severity and nature of the clinical problems. Recalcitrant sesamoid problems, unresolved by injections or insoles, can be treated with bone excision sesamoidectomy.
The thought of sustaining a turf toe from autumn sports in the UK might stimulate ideas of exercise on softer ground such as beach volleyball, but A Year on Foot at the ISEH cautions against this with the warning that your big toe is just as at risk becoming traumatised with a downward plantar-flexion sand toe injury."