Lateral Collateral Ligament Calcification - A Rare and Challenging Cause of Chronic Knee Pain

Sep 30, 2026

Lateral collateral ligament (LCL) calcification of the knee is an uncommon degenerative or posttraumatic change marked by ectopic mineral deposition within ligament fibers. A 49-year-old woman presented with chronic right lateral knee pain and recurrent acute exacerbations after mild prior trauma; radiographs were unrevealing and symptoms persisted despite physiotherapy and oral NSAIDs. Ultrasound showed a circumscribed hyperechoic calcific lesion in the LCL, and MRI confirmed the diagnosis. Radial extracorporeal shockwave therapy led to complete symptom resolution at three-month follow-up.

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CategoryHealthcare

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Reading Time13 min

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Introduction

Case Presentation

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Figures and Imaging Findings

Management and Outcome

Review began 11/11/2025 Review ended 11/30/2025 Published 12/09/2025 © Copyright 2025 Sousa et al. This is an open access article distributed under the terms of the Creative Commons Attribution License CC-BY 4.0. , which permits unrestricted use , distribution , and reproduction in any medium , provided the original author and source are credited. DOI: 10.7759/cureus.98799 Open Access Case Report Lateral Collateral Ligament Calcification: A Rare and Challenging Cause of Chronic Knee Pain José Eduardo Sousa 1, Nuno Madureira 1, Paula Freire 1, Maria João Sousa 1, Carolina Paiva 1 1. Physical Medicine and Rehabilitation, Centro de Medicina de Reabilitação da Região Centro-Rovisco Pais, Coimbra, PRT Corresponding author: José Eduardo Sousa, [jose.eduardo.sousa@gmail.com](jose.eduardo.sousa@gmail.com) Abstract Lateral collateral ligament (LCL) calcification of the knee represents an uncommon degenerative or posttraumatic change characterized by ectopic mineral deposition within the ligamentous fibers. We report a rare case of LCL calcification in a 49-year-old female presenting with chronic right lateral knee pain with recurrent acute exacerbations. The patient had a prior history of mild knee trauma, and no significant findings were initially identified on radiographs. Despite several courses of physiotherapy and oral nonsteroidal anti-inflammatory drugs (NSAIDs), her symptoms persisted with only partial relief. Physical examination revealed localized tenderness over the lateral knee compartment and pain with varus stress testing. Bedside ultrasound revealed a well-circumscribed hyperechoic lesion within the LCL consistent with calcific deposition. MRI confirmed the diagnosis. A conservative management plan consisting of radial extracorporeal shockwave therapy (rESWT) was initiated, leading to complete symptom resolution at threemonth follow-up. Categories: Physical Medicine & Rehabilitation Keywords: calcific tendinopathy, conservative treatment, knee pain, lateral collateral ligament, magnetic resonance imaging, shockwave therapy, ultrasound imaging Introduction Calcific deposition within periarticular soft tissues is a well-known phenomenon, most commonly affecting tendons such as those of the rotator cuff or gluteal region [1,2] . However, calcification of the lateral collateral ligament (LCL) of the knee is exceedingly rare, with only a few cases documented in the literature [1-4]. This entity is characterized by hydroxyapatite crystal deposition within the ligamentous fibers, resulting in localized inflammation, pain, and sometimes restricted motion [1,3] . Its precise etiology remains uncertain, though factors such as previous trauma, repetitive microtrauma, or metabolic disturbances may play a role [1,2] . Radiologically, LCL calcification can mimic more aggressive or traumatic lesions, including avulsion fractures, myositis ossificans, or even neoplastic processes [1,4] . Differentiating it from other causes of lateral knee pain-such as ligament sprain, meniscal tear, or iliotibial band syndrome-is crucial for its proper management [1,2] . Most cases respond favorably to conservative measures, including nonsteroidal anti-inflammatory drugs (NSAIDs), physiotherapy, and ultrasound-guided interventions [3,5] . We report a chronic case successfully treated with a noninvasive approach, highlighting the diagnostic value of ultrasound and MRI in managing this rare condition [3] . Case Presentation A 49-year-old female with no significant past medical history presented to our Physical Medicine and Rehabilitation (PMR) clinic with a two-year history of persistent right lateral knee pain. The pain had a mechanical pattern, exacerbated by prolonged standing or walking for more than 15 minutes, and was occasionally accompanied by localized swelling and stiffness. The patient recalled a motorcycle accident approximately six years earlier, with no reported fractures or ligamentous injury. Over the

FAQs

What is lateral collateral ligament (LCL) calcification and why is it challenging?

LCL calcification is ectopic mineral deposition within the ligament fibers, producing localized inflammation and pain. It is rare and can mimic more aggressive or traumatic knee conditions, making accurate differentiation essential.

How was the diagnosis confirmed in this case?

Bedside ultrasound identified a well-circumscribed hyperechoic lesion consistent with calcific deposition in the LCL. MRI then confirmed two calcification foci and excluded ligament discontinuity, masses, and other joint pathology.

What treatment was used and what was the outcome?

A conservative plan with radial extracorporeal shockwave therapy (rESWT) was started. The patient achieved complete symptom resolution at the three-month follow-up.

Sep 30, 2026

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