Early in the 20th century, Sever reported a condition characterised by pain in the posterior and inferior region of the heel in very active and/or overweight children. This was reported to be characterised by the enlargement of the epiphyseal line of the ossific nucleus of the calcaneus on radiographic examination, with cloudiness and obliteration of the epiphyseal line [1
]. Over a decade later, an explanation for the cause of calcaneal apophysitis was posited by Lewin [2
], who argued that it was inflammation caused by traction in opposite directions between the achilles tendon and the plantar fascia and aponeurosis.
Posterior heel pain classified as calcaneal apophysitis or sever’s disease may be a common musculoskeletal injury in children as this condition has been reported to account for between 2% - 16% of presentation at sports clinics [3
]. Calcaneal apophysitis is reported as a self limiting condition [6
], usually presenting between the ages of 8–15 years [7
], but has been observed in children as young as six [9
]. The pain related to this inflammation is though to cease after fusion of the calcaneus [1
]. However, no studies have yet reported the incidence or prevalence of this condition in the general population [10
]. Pain with walking and sport is often reported in this condition and is a cause of concern for both parent and child. The physical activity reported to produce the highest levels of pain include frequent running and jumping such as soccer [11
]. In rare cases, it has been reported that untreated calcaneal apophysitis can cause calcaneal apophyseal avulsion fractures [12
]. Beyond the pain and physical disability associated with calcaneal apophysitis, children with this condition have also been found to have lower ‘Happiness’ and lower ‘Sport/Physical Function’ subscale scores from the Paediatric Orthopaedic Surgeons of North America ‘Musculoskeletal Quality of Life’ questionnaire (n = 67), when compared to children without calcaneal apophysitis (control group n = 236) [13
The recommended treatment options for calcaneal apophysitis are varied. Only one literature review has examined literature pertaining to calcaneal apophysitis between 2008–2011, this review finding that there is no criterion based treatment path and recommended further evaluation of treatment methods [14
]. Narrative literature reviews [15
] have recommended the following treatment options: rest or cessation of sport [17
], heel lift, orthoses, mobilisation [1
] stretching or strengthening exercise programs [1
], padding for shock absorption or taping of heel [1
], ultrasound/pharmaceutical prescriptions/ice [3
], immobilisation casting and crutches [11
] and footwear prescription with appropriate support and cushioning [33
]. This review aims to synthesise the available evidence on the efficacy of treatment approaches for maintaining physical activity and reducing pain (short and long term) for children with calcaneal apophysitis.
This review has identified that there has been little methodologically rigorous evidence generated to support treatment options for calcaneal apophysitis. The available evidence indicated orthoses with a brim (heel cup) and medial arch support was more effective in reducing pain in sporting activities (Level 2 evidence) compared to heel raises or no treatment. There was also support for heel raises reducing pain in sporting activities (Level 2 evidence) compared to no treatment. Taping also appeared to have some immediate pain relief benefit (Level 3 evidence). Meta analysis was not undertaken due to the variability of data collected during this review, therefore our conclusions have been based upon a critical, narrative synthesis.
The findings of this review might be able to help shed light over the causative mechanism of calcaneal apophysitis. It is widely accepted that calcaneal apophysitis is a self-limiting condition related to physiological changes at the calcaneal apophysis as children transition to adolescence. Given the causative mechanisms of calcaneal apophysitis are still unknown, it was not surprising to find a variety of treatment approaches advocated within the literature [15
]. The treatment options reported within the literature and their success may be based on a number of theories of causative factors. Many researchers and clinicians continue to support the same baseline interventions such as ice and restriction of sports. The effectiveness of additional treatment options such as taping, heel lifts and orthotics may be based on the supposition [51
] that calcaneal apophysitis is the result of either an increased tractional pull at the calcaneal apophysis or from increased impact forces at the plantar surface of the heel.
One causative factor of increased tension or shortness of the achilles tendon may be due to the rapid growth in adolescents. This soft tissue change may have the potential to place an interim strain or traction on the apophysis at the insertion [8
], thus a simple heel raise has been advocated to reduce this strain when footwear is worn [17
]. Similarly, there may be increased tension or shearing force at the insertion of the achilles tendon due to abnormal biomechanics at the foot and ankle. During gait, the gastrocnemius and soleus muscles provide a plantarflexion mechanism at the ankle while eccentrically contracting at midstance, exerting forces on the subtalar joint [51
]. If there are abnormal forces going through the foot, the provision of a heel raise may reduce the load in the achilles tendon [53
] or an inverted type of orthotic device has the potential to reduce the supination moment [54
] and limit pronation; both items reducing the tractional pull at the achilles tendon calcaneal junction. A combination of these theories may also be plausible.
It is not known exactly how calcaneal apophysitis develops and if there is biomechanical abnormalities within the foot that results in active children having heel pain. The resultant success in pain relief an orthotic device may come into play when used on a foot with an abnormal windlass mechanism. The windlass mechanism is the theory that describes how the plantar fascia and achilles tendon interact during gait for propulsion. The plantar fascia (windlass) is like a rope or cable attached to the distal and inferior aspect of the calcaneus and the proximal and inferior aspect of the metatarsophalangeal joints. During the propulsion phase of the gait cycle, the windlass activates and shortens the plantar fascia at the metatarsals, therefore shortening the distance between the calcaneus and metatarsals. This in turn elevates the medial longitudinal arch [55
]. It is possible what in a foot with calcaneal apophysitis, the rearfoot valgus position may be impacting the windlass mechanism and changing the force required at the achilles tendon for normal gait. The use of an orthotic has demonstrated ability to influence the rearfoot position [23
] and therefore may positively impacts the windlass mechanism; this in turn may reduce the loading required at the achilles tendon for normal and pain free gait in the symptomatic child.
Impact forces or increased plantar pressures at the calcaneal area may cause repetitive impact forces during heel strike, further traumatising the apophysis [8
]. If this is also a contributing cause of the apophysitis, then the use of an orthotic with a heel cup may centre the calcaneal soft tissues (fibro fatty padding), increasing the cushioning in this area and resulting in pain relief [40
]. Likewise, a heel raise is often manufactured from material with shock absorbing properties, again providing some form of cushioning at the plantar surface of the heel.
No studies identified in this review examined the use of ‘off the shelf’ or prefabricated orthotics which have also been known to reduce foot pain in adults with plantar fasciitis [57
]. There have been no studies investigating the use of prefabricated orthotic devices in neurologically normal children with foot pain and it was surprising these were not utilised within the studies considering the increased availability to health practitioners and their relative low cost compared to custom made orthotics.
It also appears from the literature that children who play competitive sport were more likely to experience calcaneal apophysitis [41
]. This is a sub-section of the general population, therefore extrapolation of the treatment approaches and effectiveness demonstrated within these studies to children who participate in normal sporting activities levels may not be appropriate. While orthoses [38
] were more effective in pain reduction during participant-identified activities compared to heel raises, this may be due to the high impact on the apophysis of many hours of training or an early sporting injury due to abnormal biomechanics and strain. In the child who plays normal school sports or minimal sport after school, the use of a heel lift may be just as effective in pain relief.
Overall, the treatment options reported, both work on similar principles, however the level of effectiveness may actually be based on the original cause of the pain. A regular foot posture and normal foot biomechanics may only require a heel lift to relieve pain, yet the child who has additional foot posture changes may require some type of orthotic with or without a heel lift to improve foot function. Additional domains need to be explored to better understand efficacy of treatment options, including: establishing the level of sport played by children who demonstrate this pain, determination of any ankle equinus and understanding if there is a particular foot type that is more receptive to one treatment over another.
The authors declare that they have no competing interests.
All authors (AMJ, CW, TPH) contributed to the conception and design of this systematic review. AMJ and CMW completed the systematic review and scoring of the selected articles. All authors have contributed to the analysis and have read and approved the final manuscript.