FOOT INJURIES Other conditions that occur in the forefoot Figure 6: Stress fracture of one sesamoid

Injury to the sesamoid bones includes traumatic fracture (Fig.6), stress fracture and sesamoiditis. The injury occurs as a result of high impact trauma from a height eg. ballet dancers, basketball or in a sport where forced dorsiflexion of the great toe occurs eg. sprinting.

Clinical picture Pain, swelling and tenderness is localised to the affected sesamoid. Patients generally walk with an antalgic gait and supinate the foot to keep weight away from the painful sesamoid. Diagnosis is made on history, clinical examination and radiological findings.

Investigations ● Plain radiographs - AP, oblique and skyline views of both feet are recommended ● Isotope bone scan

Treatment ● Ice, rest and physiotherapeutic modalities ● Padding ● Foot orthoses with first ray cutout ● Steroid injection ● Surgery as the last resort, and only in cases where there is con- siderable osteonecrosis ● Partial sesamoidectomy may provide relief of symptoms

5. STRESS FRACTURE OF THE NAVICULAR Stress fracture of the navicular is mainly seen in athletes whose sport involves sprinting, jumping or hurdling. The cause of the frac- ture is thought to be resistance to the pull of tibialis anterior and tibialis posterior muscles when the foot is plantarflexed. The direc- tion of the fracture is usually transverse in line with the middle/medial cuneiform joint and the first metatarsal.

In children, the condition is called Kohler’s disease (Fig.7) and usu- ally occurs as a result of trauma, or too much high impact activity.

● Hallux limitus/rigidus ● Hallus valgus ● Clawed toes/hammer toes ● Subungual haematoma (Black toenail) ● Subungual exostosis ● Ingrowing toenail (onychocryptosis) ● Corns and calluses ● Synovitis of the metatarsophalangeal joints ● Inter and plantar metatarsal bursitis ● Plantar plate injury ● Ganglion of the extensor hallucis longus tendon ● Plantar warts ● Blisters

This causes damage to the growing bone which then undergoes avascular necrosis. If recognised early enough, with rest and min- imising impact, the bone can regenerate.

Clinical picture There is diffused pain over the midfoot, which is brought on by activity and high-heeled shoes. Often the foot will be swollen espe- cially at the end of the day. The pain or ache generally settles quick- ly with rest. Palpation over the navicular bone often referred to as ‘N’-spot, will produce unbearable pain and is fairly diagnostic of the condition.

Investigations ● Plain radiographs are not very useful and will reveal a stress fracture of the navicular in only a small percentage of patients. It is necessary to exclude other pathology ● Isotope bone scan is the investigation of choice (Fig.8) ● Bone scan is followed by CT scan for confirmation and evalua- tion of the fracture. 2mm slices with views taken by reversing the CT scan gantry will provide the best exposure of the fracture site (Fig.9) ● MRI scans

Treatment Management of this condition is based on clinical findings. If the ‘N’ spot remains painful, conservative treatment must continue until totally asymptomatic, or opt to manage the condition surgically: ● Immobilisation in a non-weight bearing cast for 4-6 weeks ● Foot orthoses ● Surgery

Figure 7: Medial and superior radiograph views of Kohler’s disease

Figure 8: Isotope bone scan of stress fracture of the navicular

Figure 9: CT scan of stress fracture of the navicular SportEX 13