Disorders of the forefoot and toes
The forefoot
Short first metatarsal bone
This is known as Morton’s syndrome. Sometimes a short first metatarsal is related to pain, sometimes it is not. If the first metatarsal is too short and hypermobile, most of the body weight will be borne by the second metatarsal. Because of the hypermobility and shortening, the transverse arch becomes depressed and metatarsalgia results (p. e308 of this chapter).
March fractures
This condition was first described in 1855 by Breithaupt,1 a Prussian military doctor, who stated that many soldiers developed painful swellings at the dorsum of their feet after long marches. He called this Schwellfuss but the cause remained unclear until Stechow2 proved that the condition is caused by stress fracture.
Stress fractures of the metatarsal bones comprise 3.7% of all sport-related injuries, with the second and third metatarsal accounting for 80–90% of the fractures.3–5 Stress fractures of the metatarsals are also common in military recruits and in long-distance runners. It has been reported that up to 20% of stress fractures in athletes6 and 23% of stress fractures in military recruits7 are located in the metatarsals.
The lesion should be suspected when a patient presents with unilateral and localized warmth and oedema at the dorsum of the foot. Often the symptoms appear after a long walk but sometimes there is no specific precipitating activity. It is surprising that children are almost as liable to marching fractures as adults. Cyriax’s8 (his p. 440) youngest patient was a 6-year-old boy.
During the first few days, the fracture (usually a hair-line crack) may not be revealed by routine radiography. The diagnosis is confirmed after a few weeks, when the callus formation around the fracture becomes radiologically apparent. Earlier confirmation of the diagnosis is obtainable by either radionuclide bone imaging,9,10 or ultrasound examination.11–13
Differential diagnosis
Localized swelling, warmth and tenderness in the forefoot can also occur in:
• Gout in one of the tarsometatarsal joints. A history of recurrent acute attacks of arthritis at the same joint or in other joints is helpful.
• Rheumatic forms of arthritis, such as rheumatoid arthritis, psoriasis and reactive arthritis. These disorders affect multiple joints. The history is also longer than the usual 6 weeks of that of a march fracture.
• Freiberg’s arthritis at the second metatarsophalangeal joint. Although ischaemic epiphyseal necrosis of the base of the second metatarsal bone occurs in adolescence, the disease may be asymptomatic until adult life, when the deformity of the joint and the degenerative arthritis produce pain.
• Ringworm and erysipelas. Local cellulitis, caused by an infection of β-haemolytic Streptococci spp. or fungi, can cause considerable redness, thickening and tenderness. In erisypelas, there is malaise, chills and fever, together with an increased erythrocyte sedimentation rate. In ringworm, there is considerable itching and inspection of the interdigital clefts very often reveals a small localized infection between two toes.
Treatment
The patient lies supine on the couch. The therapist sits facing the foot and with the ipsilateral hand encircles the toes in such a way that the thumb lies at the dorsal aspect and the proximal interphalangeal joint of the flexed index finger presses under the metatarsophalangeal joints. The big toe is left free. The thumb keeps the toes flexed and the index finger presses upwards, so as to render the metatarsus convex. The shafts move apart and the muscle bellies lie closer to the surface. The middle finger of the other hand, reinforced by the index finger, is now placed in the groove between the two metacarpal bones (Fig. 1). Fingers, wrist and forearm are kept in one line and parallel to the metatarsal bones. Deep friction is imparted by rotating the fingers through an alternate pronation and supination movement of the forearm, so that the muscle is moved between the fingertip and the metatarsal shaft.
Fractures of the fifth metatarsal
Tuberosity avulsion fractures are the most common and usually complicate an inversion sprain (see p. 776). The majority heal with symptomatic care in a hard-soled shoe.
The true Jones fracture is defined as an acute fracture at the junction between the proximal diaphysis and metaphysis of the fifth metatarsal without distal extension beyond the fourth to fifth intermetatarsal articulation.14 The mechanism of injury is believed to be an abduction force applied to the forefoot with simultaneous ankle plantar flexion.15 A Jones fracture can be treated with 6 to 8 weeks of non-weight-bearing immobilization resulting in fair to good outcomes.16,17 Operative treatment is selected if the patient is a high-performance athlete or nonoperative treatment fails.18
A proximal diaphyseal fifth metatarsal stress fracture is defined as a stress fracture in the zone of the proximal fifth metatarsal immediately distal to the Jones fracture’s anatomic area.19 The mechanism of this injury is believed to be a repetitive load applied under the metatarsal head over a relatively short time, resulting in an overuse phenomenon. A proximal diaphyseal fifth metatarsal fracture may have a very long healing time and non-union can develop in as much as 25% of cases. For this reason, operative treatment is usually recommended.20
Splay foot
Treatment includes a high heel with a horizontal upper surface, which prevents the forwards gliding of the talus and thus releases the forefoot (see Ch. 59), and energetic training of the short plantiflexor muscles of the toes.
Localized splaying indicates a ganglion lying between two metatarsal heads. When the patient stands, an excessive interval is seen between two toes and palpation reveals a semisolid tumour keeping the heads apart (see p. e309 of this chapter).
The first metatarsophalangeal joint
The capsule of the first metatarsophalangeal joint is reinforced on the plantar surface by a fibrocartilaginous plate that is attached distally to the proximal phalanx and proximally to the plantar aspect of the neck of the first metatarsal. This volar plate contains the two sesamoid bones, inserted in the tendons of the flexor hallucis brevis (Fig. 2). The flexion–extension movement is a rolling and sliding of the metatarsal head within the stable support made up of the base of the proximal phalanx and the volar plate.21
The joint is extremely important for normal gait. There must be 60–70% of extension with the first metatarsal to allow the hallux to function normally during the stance phase of gait.22 In the final stage of forefoot contact, 40% of body weight is imposed on the joint and the big toe23 (Fig. 3).
During extension, the sesamoids are drawn from the head–neck junction of the first metatarsal to the distal head area. The average range of motion is 50°.24 Apart from their function in weight bearing, the sesamoids also serve as a fulcrum that increases the mechanical advantage of the flexor hallucis brevis tendon.
The clinical examination of the big toe is summarized in Box 1.
The capsular pattern
The capsular pattern at the first metatarsophalangeal joint is slight limitation of flexion, together with marked limitation of extension (Fig. 4).
Gout
The first metatarsophalangeal joint is usually the first joint to be affected in gout. The attack is characterized by a sudden onset of intense pain, frequently at night. The joint is swollen and exquisitely tender. The overlying skin is tense, warm and dusky red. The attack lasts 1–2 weeks, and asymptomatic periods of months or years commonly follow the initial acute attack.25
An acute attack can frequently be aborted by colchicine or by one of the non-steroidal anti-inflammatory drugs.26–28 When attacks are frequent or other gouty complications such as tophi occur, lowering of blood uric acid is indicated.29
Arthritis in adolescence
Early osteoarthrosis at the first metatarsophalangeal joint, mostly bilateral, occurs in adolescence and is the result of osteochondritis dissecans.30 It leads to the formation of a hallux rigidus in young adults.
Because the patient is unable to extend the big toe during the foot-off phase, treatment must aim to introduce a forefoot movement that does not interfere with the mobility of the joint but nevertheless enables the heel to move upwards while the forefoot is on the ground. To do this, a ‘rocker’ is placed in or under a thick and solid sole of a shoe, at the joint line (Fig. 5).
Instead of extending at the first metatarsophalangeal joint, the forefoot will now rock during a normal gait. If this is not adequate, a steel plate in the sole prevents further stress on the rigid joint, but the resulting gait is less natural.31
Surgery for hallux rigidus consists of resection of osteophytes and metatarsal head (cheilectomy)32 or resection arthroplasty.33–35
Traumatic arthritis
This results from a direct trauma or forceful hyperextension of the joint. This is the case in osteoarthrosis, in which a superimposed post-traumatic arthritis easily occurs. It is also encountered in certain sports, such as soccer and American football.36–39 Treatment consists of an intra-articular injection of 10 mg of triamcinolone and prevention of further overstretching.
Arthrosis in middle age
Osteoarthrosis at the first metatarsophalangeal joint (MPJ) is the second most common disorder affecting the foot after hallux valgus. The prevalence of the condition increases with age, and it has been reported that radiographic changes in the first MPJ are evident in approximately 46% of women and 32% of men at 60 years of age.40 The degeneration and stiffness is not the result of a previous aseptic necrosis but has probably been induced by trauma or repetitive stresses. Sometimes a heavy weight falling on the joint or a fracture is the precipitating cause. Repetitive stresses during extension (as in women wearing high heels) can influence the degeneration.
Deterioration is slow and insidious, and therefore symptoms may not arise for years. They appear only when the joint becomes overstrained.41 In other words, the source of the pain is not the osteoarthrosis as such but the superimposed post-traumatic arthritis. Symptoms therefore start when some dorsiflexion is lost: in men when 45° of extension range has been lost, in women who wear high heels when only 20 or 30° has been lost. The typical case is consequently a middle-aged man or woman who has pain at the big toe during and after walking.
Clinical examination shows a painful and markedly limited extension of the big toe, together with slight limitation of flexion. The end-feel is hard. Osteophyte formation and some local tenderness can be palpated at the dorsum of the joint.42
Because the pain is the result of a post-traumatic arthritis, it can be abolished by one intra-articular injection of triamcinolone. If the patient is careful in the future, wears appropriate shoes with thick, solid soles and avoids high heels, relapses are not to be expected. During the last decade an alternative treatment termed ‘viscosupplementation’ – the intra-articular injection of hyaluronan with the aim of restoring the viscoelasticity of the synovial fluid – has been proposed and studies show promising results.43,44 Good results can also be achieved by traction. Alternatively, mobilization, using traction–translation techniques can be used.45 In advanced cases, in which there is hallux rigidus, the use of a ‘rocker’ and a steel sole must be advised (Fig. 5). If all conservative treatment fails, surgery can be undertaken.46,47
The patient sits with the foot flat on the couch. The physician grasps the distal phalanx and pulls it in an axial direction, with a slight flexion component. This distracts the joint surfaces and enables the joint line to be identified, which is not always easy to do in patients with large osteophytes: the depression between the osteophyte and the bone should not be mistaken for the joint line. A 1 ml syringe is filled with steroid suspension and fitted with a thin 2 cm needle. After identifying the joint line and the tendon of the long extensor, the needle is passed into the space between the two bones, medially to the tendon (Fig. 6) and the steroid is injected.
Rheumatoid arthritis
This disease often affects the metatarsophalangeal joints.48 The usual signs and symptoms of an inflamed joint are seen. The patient has nocturnal pain and morning stiffness. Clinical examination reveals a capsular pattern and a capsular thickening at a warm and swollen joint. Treatment is causative.
