Differential Diagnosis
TA Rupture
Acute TA ruptures occur in between 7 & 13 per 100000 every year, with a recent increase in the prevalence of the injury due to increased participation in recreational sports. The incidence is highest in males between the ages of 30 & 39 years, with up to 75% of injuries occurring during sporting activity (Nandra et al, 2011; Maffuli et al, 2014). Ruptures usually occur due to biomechanical influences and degenerative changes in the TA in the form of AT, which may be clinical or subclinical, depending on the presence of symptoms preceding rupture (Alfredson et al, 2009). If Achilles rupture is suspected, there are tests that may be carried out to assess this. The American Academy of Orthopaedic Surgeons produced guidelines for the diagnosis and treatment of TA rupture, based on a systematic review of the literature. The guidelines found that the Thomson (squeeze) test, decreased ankle plantarflexion strength, presence of a palpable gap and increased passive ankle dorsiflexion range of motion were the most accurate clinical tests for the diagnosis of TA rupture (AAOS, 2009). Other clinical tests to out-rule a rupture of the TA are the Matle’s test, which involves placing the patient in prone and flexing both knees to 90° and placing the ankle joint into neutral. If the effected side displays more dorsiflexion at perceived neutral, the result is positive for TA rupture (Reiman et al, 2014). Matle’s test displayed high sensitivity and specificity for the detection of an TA rupture. This systematic review found that the calf squeeze test (Thomson’s test) and palpation for TA gap were the most sensitive and specific tests for TA rupture, followed by Matle’s test (Reiman et al, 2014).
Management of the TA rupture is controversial. In the sedentary population (25%) of ruptures conservative management may be favoured, though this may lead to weakened muscle, and up to 13% re-rupture (Maffuli et al, 2014). Surgical management is invasive and risks of complications are up to 20 times that of conservative management (Maffuli et al, 2014). Surgical management should be approached with caution in the following groups; diabetics, those with peripheral neuropathies or peripheral vascular disease, those above the age of 65, those with immunocompromised states, sedentary lifestyles or obese (AAOS, 2009). The most common complications are infection and re-rupture.
Retrocalcaneal bursitis
The function of the retrocalcaneal bursa is to allow transmission of force from the TA to the calcaneus without creating excessive tissue tension. It does this by allowing the separation of the tendon from the bone during plantarflexion, as the angle of the tendon’s path along the bone increases (Canoso et al, 1988). It is often difficult to differentiate the source of pain in this region between the bursa and the TA. Pain is usually caused by strong or repetitive triceps surae contractions, often involving extremes of range, such as hopping, jumping, running and uphill walking (Frey et al, 1992). Diagnosis may be performed following thorough subjective and objective examinations to distinguish it from AT, and may be confirmed using ultrasonography, MRI or CT scans (Frey et al, 1992). Physiotherapy intervention may require biomechanical correction, anti-inflammatory advice, stretching and the use of heel wedges, however failing conservative management, surgical options are available. Surgical management involves resection of the calcaneus, though on 6 year follow up, only 50% success rate was demonstrated (Angermann et al, 1990).
Posterior impingement syndrome
Posterior impingement syndrome constitutes a group of pathologies that result from repeated plantar flexion of the foot, leading to compression and trapping of soft tissues between the posterior aspect of the distal tibia and the superior surface of the calcaneus (Sainani et al, 2011). Posterior ankle pain sometimes occurs post calcaneal fractures, and usually takes the form of posterior impingement syndrome or Haglund’s deformity (Lui, 2008). This condition most often effects athletes and dancers, and seldom presents in an inactive population, with ballet dancers, horizontal jump athletes and soccer players predominantly implicated (Ribbans et al, 2015; Rogers et al, 2010). It is most often caused by os trigonium, posterior tenosynovitis, or Shephard’s fracture of the posterolateral talus (Ribbans et al, 2015). This may present as a dull ache in the heel area or a sharp pain on activities in plantar flexion, such as ‘en pointe’ work in dancing, or hopping/jumping (Vali et al, 2014). Subjective and objective assessments are required for diagnosis of posterior impingement syndrome. Objective assessment should include palpating the talus and calcaneus of point tenderness. Radiographic imaging may be necessary to detect the presence of body or soft tissue abnormalities in the region that may be causing the pain (Vali et al, 2014).
Dislocation of peroneal tendons
Peroneal tendon injuries are one of the most common complications of calcaneal fractures (Lui, 2008). They are often mistaken as lateral ankle ligament injuries, and usually occur in sports involving rapid direction changes such as hockey and football. Dislocation and subluxation of the peroneal tendons occur when the peroneal muscles are forcefully contracted while the foot is in a dorsiflexed and inverted position (Roth et al, 2009). Clinical tests include palpation of the retrofibular region for pain or tenderness & active range of motion testing to produce a click in forced end of range plantarflexion and eversion (Roth et al, 2009). Active dorsiflexion and eversion of the foot from a position of inversion and plantarflexion will determine if active contraction of the peroneal muscles reproduces the pain (Roth et al, 2009).
Stress fracture
Stress fractures are among the top three overuse injuries reported in athletic populations, with particularly high prevalence among those who participate in soccer, running, gymnastics and dance (Siobhani et al, 2013). Repetitive activity and increased training load appear to be risk factors for the development of stress fractures (Chen et al, 2006). Stress fractures can appear in the navicular bone (Mann, 2009), metatarsal bones (Watson, 2013), the cuboid (Beaman et al, 1993) or in the calcaneus (Aldridge, 2004) in athletes and diagnosis is usually through radiographic imaging.
Sural nerve irritation or neuroma
The sural nerve descends between the two heads of gastrocnemius and gives cutaneous branches to the posterior and lateral aspects of the lower third of the leg. It also supplies the lateral calcaneus, heel, ankle and along the lateral border of the foot to the 5th terminal metacarpophalangeal joint (Pringle et al, 1974). The sural nerve can become irritated in the posterior compartment of the lower limb, along its course through the posterolateral ankle (Pringle et al, 1974). It can also become injured due to direct trauma to the posterior leg, usually in the area of its course through the heads of gastrocnemius. It may present with numbness or pain to the lateral ankle and heel (Babwah, 2012).
Sever’s disease
Also known as calcaneal apophysitis, Sever’s disease is posterior heel pain that presents mostly in physically active children aged between 8 and 14 years old. This pain accounts for up to 15% of musculoskeletal injuries in children this age (Howard, 2014). Sever’s disease is believed to be caused by overuse and microtrauma, leading to repeated microavulsions at the junction of the bone and cartilage, with no time for the bone to heal (Howard, 2014). Diagnosis is usually through comprehensive subjective history, and a positive squeeze test of the medial and lateral heel, reproducing pain. The condition is usually self-limiting, with limited evidence to support the use of orthoses and heel raises (James et al, 2013).
Os trigonium
The os trigonium is a small bone at the posterior aspect of the talus that fails to fuse with the talus in approximately 3-15% of people (Jones et al, 1999). The os trigonium injury is characterised by pain and swelling in the posterolateral region of the ankle, and some of the mechanisms of injury described include avulsion by the posterior talofibular ligament, direct trauma to the posterior aspect of the ankle, repeated trauma form repetitive hyperplantarflexion, or an acute episode of hyperplantarflexion (Jones et al, 1999). Diagnosis can be difficult as it often presents similar to other conditions of the posterior foot, including flexor hallicus injuries and is often concurrent with posterior impingement syndrome. Therefore, imaging is most often used in the diagnosis of this condition (Jones et al, 1999).
Tarsal tunnel syndrome
Tarsal tunnel syndrome is an entrapment neuropathy involving compression of the posterior tibial nerve beneath the flexor retinaculum in the posterior compartment of the ankle, caused by either trauma or repetitive injury (Plyler et al, 2012). Other causes identified include hypertrophic retinaculum, osteophytes or lipoma (Ahmed et al, 2012). The predominant symptom is pain over the tarsal tunnel behind the medial malleolus with radiation to the longitudinal arch and plantar aspect of the foot, including the heel, with secondary symptoms of tightness, burning, tingling and numbness over the same distribution (Ahmed et al, 2012). Symptoms are exacerbated by walking, running or standing. Tinel’s sign and pain provocation tests such as combined dorsiflexion and eversion can be used for diagnosis. Conservative management may include anti-inflammatory medication, activity modification and mobilisations. Limited evidence has emerged supporting the use of night splints and orthotic insoles, though this is inconclusive (Ahmed et al, 2012).
Tenosynovitis
Achilles, peroneal and tibialis anterior tenosynovitis involve inflammation of the tendons outer sheath. In the TA this is often called the paratenonitis. Paratenonitis presents in approximately 15% of Achilles tendinopathies (Pierre-Jerome et al, 2010). It can occur acutely in runners, and is believed to be caused by increased extrinsic pressure, causing friction between the TA and its overlying sheath (Pierre-Jerome et al, 2010). Very little evidence exists supporting the conservative management of paratenonitis, and surgical management has been described with some favourable results (Kvist & Kvist, 1980).
Tibialis posterior tendon dysfunction/tendinopathy
Rupture of the tibialis posterior tendon is associated with acquired adult flatfoot, as this is a muscle which supports the arch. Rupture of the tendon can occur with ongoing dysfunction of the tendon preceding the injury (George & Davis, 2008). Injury may occur in endurance athletes, and occurs most often in runners and triathletes (Howitt et al, 2009). Tendon dysfunction presents with swelling and pain posterior to the medial malleolus and pain weight bearing (Howitt et al, 2009). Stage 1 dysfunction presents with mild swelling, medial ankle pain and normal but possibly painful heel raise. Stage 2 dysfunction presents with progressive flattening of the medial arch of the foot, with secondary abduction of the mid-foot and an extreme difficulty maintaining heel raise. Stage 3 presents with similar to stage 2, however there may be a fixed hindfoot deformity (Kulig et al, 2009). A randomised control trial of non-surgical interventions for tibialis posterior tendon dysfunction found that the condition responded well to the provision of orthoses and stretching and found much lower pain scores and increased perceived function score in groups that participated in progressive resisted concentric and eccentric exercises (Kulig et al, 2009).
Arthritic condition
Arthritis at the ankle is most often of post-traumatic aetiology, and those who present with the condition usually have a history of fracture (Thomas & Daniels, 2003). Ankle conditions can also commonly present in patients with Rheumatoid arthritis (RA), with up to 90% of people suffering from RA affected by foot and ankle problems (Waller et al, 2012). Ankle arthritis presents with pain and swelling across the joint line, as well as limited painful range of motion. A detailed subjective assessment is important in distinguishing this condition, and radiographic imaging can be used to confirm the diagnosis (Thomas & Daniels, 2003).
Plantar fasciitis
Plantar fasciitis presents in up to 10% of the population and is particularly prevalent in endurance athletes and dancers (Anderson & Stanek, 2013). The condition effects the aponeurosis extending from the medial tuberosity of the calcaneus to the heads of the metatarsal bones, and presents with sharp heel pain that is worst in the morning when taking the first steps of the day, and can become irritated by standing or walking for a prolonged period of time (Serbest et al, 2013). Pain is usually localised to the medial calcaneal tubercle, and can be reproduced by stretching the plantar fascia or by palpation of the heel and proximal aspects of the fascia (Serbest et al, 2013). Treatment of plantar fasciitis is multi-factorial with limited evidence to support gastrocnemius & soleus stretching (Garrett & Nerbert, 2013; Almubarak, 2012), foot orthoses (Anderson & Stanek, 2013), dorsiflexion night splints (Lee et al, 2012), extracorporeal shockwave therapy or steroid injection (Serbest et al, 2013) in isolation.
Haglund’s Deformity
Haglund’s Deformity is the enlargement of the posterosuperior prominence of the calcaneus, which is sometimes associated with insertional AT (Kang et al, 2012). It is believed to be caused by repeated pressure between the calcaneus and the TA, leading to inflammation and swelling at the superior aspect of the posterior calcaneus, and can often present with an inflamed retrocalcaneal bursa (Bulstra et al, 2014). Clinically, it may be possible to observe a lateral calcaneal protuberance, with regional inflammatory changes. Radiographic imaging can be used to distinguish Haglund’s deformity from isolated retrocalcaneal bursitis, superficial TA bursitis or insertional tendinopathy (Sofka et al, 2006). Conservative management for this condition can include re-evaluation of footwear, heel inserts and oral anti-inflammatories (Sofka et al, 2006). Surgical options may include retrocalcaneal decompression, calcaneal ostectomy or osteotomy. These have varying results and re-occurrence of symptoms happens frequently if inadequate bone is resected. Other surgical complications may include excessive scar tissue formation, nerve entrapment, weakening or rupture of the TA, or non-union of the calcaneal osteotomy (Brunner et al, 2005).
Assessory soleus muscle injury
The soleus muscle is most often injured when the knee is in flexion, unlike the gastrocnemius muscle which is injured in knee extension. As it is a deep, multi-pennate muscle with good vascularity, ultrasound imaging for the diagnosis of soleus injury is unreliable (Balius et al, 2014). MRI imaging may be used by top level athletes to confirm diagnosis, but this injury usually resolves very well, and can be assessed clinically with pain in dorsiflexion with knee flexed. Therefore MRI is seldom required and conservative management is sufficient (Balius et al, 2014).