Risk factors and associated factors for calcaneal apophysitis (Sever's disease): a systematic review.

Objectives: The aim of this review was to identify the potential intrinsic and extrinsic risk factors (RFs), associated factors (AFs) and consequences of developing calcaneal apophysitis (CA).

Design: Systematic review.

Data Sources: Cochrane Library, Embase, Medline Ovid, PubMed, Web of Science and Evidence, searched from inception to April 2021.

Eligibility Criteria: We included cohort, case-control and cross-sectional studies that were conducted in patients younger than 18 years who were exposed to RFs or who presented with factors associated with developing CA. Studies in languages other than English or Spanish were excluded.

Data Extraction And Synthesis: Two reviewers worked independently to evaluate the risk of bias of included studies. The Newcastle-Ottawa Scale (adapted version) was used.

Results: A total of 736 studies were identified and 11 observational studies fully met the inclusion criteria, including 1265 participants with a mean age of 10.72 years. Four studies identified extrinsic factors, 10 identified intrinsic factors and three identified both. The extrinsic and intrinsic RFs, AFs and consequences of CA include limitation of ankle dorsiflexion, foot alignment, stiffness and mobility of the midfoot, plantar pressures and ground reaction force, body mass index, age, gender, presence of other osteochondroses and practice of sport. The risk of bias varied, being either moderate or low.

Conclusions: Regarding the factors and consequences associated with CA (Sever's disease), ankle dorsiflexion limitation is the most frequent intrinsic factor studied, followed by peak plantar pressures and foot malalignment. However, disagreements between the investigators of the included studies were found; in some cases, there is a lack of unanimity between different studies as to which factors are considered to be RFs, AFs and consequences.

Prospero Registration Number: CRD42021246366.