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Avoiding anchoring bias in unexplained chronic pain: an unexpected diagnosis of synovial osteochondromatosis
  1. Rehana Murani1 and
  2. Ranita Harpreet Kaur Manocha1,2
  1. 1Physical Medicine & Rehabilitation, University of Calgary Cumming School of Medicine, Calgary, Alberta, Canada
  2. 2McCaig Institute for Bone and Joint Health, University of Calgary, Calgary, Alberta, Canada
  1. Correspondence to Dr Ranita Harpreet Kaur Manocha; ranita.manocha{at}


Unconscious biases may influence clinical decision making, leading to diagnostic error. Anchoring bias occurs when a physician relies too heavily on the initial data received. We present a 57-year-old man with a 3-year history of unexplained right thigh pain who was referred to a physiatry clinic for suggestions on managing presumed non-organic pain. The patient had previously been assessed by numerous specialists and had undergone several imaging investigations, with no identifiable cause for his pain. Physical examination was challenging and there were several ‘yellow flags’ on history. A thorough reconsideration of the possible diagnoses led to the discovery of hip synovial osteochondromatosis as the cause for his symptoms. Over-reliance on the referral information may have led to this diagnosis being missed. In patients with unexplained pain, it is important to be aware of anchoring bias in order to avoid missing rare diagnoses.

  • musculoskeletal syndromes
  • degenerative joint disease
  • medical education
  • orthopaedics
  • rehabilitation medicine

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  • Contributors RHKM conceived of this case report. RHKM and RM critically reviewed the literature and drafted and revised the manuscript. Both authors read and approved the final manuscript, and agree to be accountable for all aspects of the work if questions arise related to its accuracy or integrity.

  • Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.