Early triage of a patient with metastatic melanoma presenting as mechanical knee pain – a case report

ABSTRACT

Physical therapists (PTs) working in primary care settings commonly encounter mechanical causes of knee pain. Non-mechanical causes of knee pain, such as bone tumors, are rare, and therefore, PTs often have a low index of suspicion regarding sinister pathology. The purpose of this case report is to describe the physical therapist’s clinical reasoning process for a 33-year-old female presenting with medial knee pain and a subsequent history of metastatic melanoma. Initially, subjective and objective testing pointed to a mechanical internal derangement of the knee. However, symptom progression and poor treatment responses between physical therapy visits 2 and 3 raised suspicions as to the cause of the knee pain. This prompted an orthopedic referral and medical imaging, revealing a large bone tumor invading the medial femoral condyle, which was further characterized as metastatic melanoma by a specialty oncology team. Further imaging revealed several metastatic subcutaneous, intramuscular and cerebral lesions. This case highlights the importance of the ongoing medical screening process, including the monitoring of symptoms and treatment responses.

Summary

• Clinicians should have a high index of suspicion in patients with a prior cancer diagnosis and unresolving pain without a relevant explanation or injury.

• The screening process should include active monitoring of treatment responses and appropriate referral for plain radiographs where hypothesized timeframes are exceeded or sinister pathology is suspected.

• Early specialist referral and subsequent oncology team referral is imperative for bone tumors, to assess metastatic disease and initiate treatment.

KEYWORDS:

• Mechanical knee pain
• physical therapy
• medical screening
• metastatic melanoma
• treatment response
• case report

Disclosure statement

No potential conflict of interest was reported by the authors.

Informed consent

Signed informed consent was obtained from the patient to publish this report, including the use of medical imaging and injury details. All attempts have been made to de-identify the patient.

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

The author(s) reported there is no funding associated with the work featured in this article.

Notes on contributors

Rohil Chauhan

Rohil Chauhan is an Auckland-based physiotherapist working in musculoskeletal private practice and as an Orthopedic-Triage physiotherapist in an orthopedic spine clinic. He is a master’s student at Auckland University of Technology with an interest in diagnostics and the treatment of spinal, knee and shoulder injuries. He is the current Secretary for the Auckland Branch of Physiotherapy New Zealand committee.

William Boissonnault

William Boissonnault is Professor Emeritus, University of Wisconsin–Madison. He was a founding member of and Curriculum Director for the University of Wisconsin Hospital/Clinics and Meriter Hospital Orthopedic Physical Therapy Clinical Residency Program. Dr. Boissonnault holds multiple adjunct physical therapy faculty positions, presenting nationally and internationally and teaching differential diagnosis, diagnostic imaging, and communication skills. He is editor of the textbook Primary Care for the Physical Therapist; Examination and Triage (Elsevier Saunders 1st and 2nd editions) and past co-editor of Pathology: Implications for the Physical Therapist I (Saunders 1st and 2nd editions). He has multiple journal publications related to differential diagnosis and physical therapist practice. Dr. Boissonnault is past-president of the Foundation for Physical Therapy, the profession’s national research fund-raising organization and past-president of the Academy of Orthopaedic Physical Therapy of the APTA. In addition, he chaired the APTA Manipulation Legislative Task Force and the American Academy of Orthopaedic Manual Physical Therapists Practice Committee.

Nicholas Gormack

Nicholas Gormack is a highly experienced and qualified orthopedic surgeon. Nick is a fellow of the Royal Australasian College of Surgeons (FRACS) and has continued to develop his knowledge and expertise through orthopedic research. Nick is also heavily involved in registrar and junior doctor training and education. Nick’s specialty interests include sports and arthroscopic reconstructive surgery on the knee, hip and shoulder. He also specializes in lower limb arthroplasty and revision arthroplasty surgery, adolescent and young adult hip preservation surgery, orthopedic trauma surgery and orthopedic tumor reconstruction.

Steven White

Steven White is a physiotherapist and senior lecturer at Auckland University of Technology where he is the Course Leader and lecturer for the postgraduate and undergraduate musculoskeletal physiotherapy papers. Steve had 27 years’ experience in his private practice managing patients with musculoskeletal pain prior to his academic appointment in 2003. Throughout his time in clinical practice, he had a passion for teaching. He has tutored on the NZ Manipulative Physiotherapists Association continuing education program since 1982 and has also been invited to speak and run courses throughout New Zealand, in Australia and the USA. Steve’s key area of interest is the diagnosis and management of musculoskeletal pain, with a particular emphasis on diagnostic accuracy and clinical reasoning. His PhD explored the diagnostic accuracy of the clinical examination for determining the presence of symptomatic intra-articular pathology of the hip. He is currently supervising a number of doctoral and master’s students.