Iatrogenic instability of the lateral meniscus after partial meniscectomy
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Published on: July 6, 2022
Marco Kawamura Demange1, Arvind Von Keudell, Andreas Hans Gomoll
1University of São Paulo, São Paulo, Brazil. demange@usp.br
Background:
Partial resection of the lateral meniscus can lead to iatrogenic instability of the remnant, resulting in recurrent locking episodes. Due to the innocuous appearance on MRI, the etiology of the locking episodes can be difficult to determine, leading to delays in diagnosis and treatment of this entity.
Case Description:
We describe two cases of unstable lateral meniscus posterior horn remnants after previous partial meniscectomy for meniscal tear. Both patients initially presented with lateral pain without mechanical symptoms and were treated with partial meniscectomies. They developed new locking symptoms after initial arthroscopies, and worsened after repeat arthroscopy with removal of additional meniscal tissue. Both patients had their locking symptoms questioned and been accused of malingering by previous physicians due to the benign MRI findings. They were treated successfully by completion meniscectomy.
Literature Review:
Few studies investigate atypical locking symptoms secondary to undiagnosed lateral meniscus tears. No previous case reports have described knee locking after partial lateral meniscectomy secondary to iatrogenic posterior horn remnants instability.
Clinical Relevance:
New onset mechanical symptoms after partial resection of the lateral meniscus body can be due to posterior horn instability with subluxation under the femoral condyle. This entity appears benign on MRI, requiring a high index of suspicion to make the diagnosis.
Insights
Recurrent knee locking after partial lateral meniscus surgery can stem from unstable remnants. A high suspicion is needed for diagnosis, as MRI may appear normal, with completion meniscectomy offering successful treatment.
Area of Science:
- Orthopedic Surgery
- Sports Medicine
- Knee Biomechanics
Background:
- Partial lateral meniscus resection can cause iatrogenic instability of the remnant.
- This instability may lead to recurrent knee locking episodes.
- The innocuous appearance on MRI can delay diagnosis and treatment.
Observation:
- Two cases of unstable lateral meniscus posterior horn remnants after partial meniscectomy are presented.
- Patients developed new locking symptoms post-arthroscopy, with worsening after repeat procedures.
- Benign MRI findings led to questioning of symptoms and accusations of malingering.
Findings:
- New mechanical symptoms post-partial lateral meniscus resection can result from posterior horn instability and subluxation.
- This condition may present with seemingly benign MRI findings.
- Completion meniscectomy successfully resolved locking symptoms in both cases.
Implications:
- Clinicians should maintain a high index of suspicion for iatrogenic lateral meniscus instability causing knee locking.
- Atypical mechanical symptoms after meniscectomy warrant thorough evaluation beyond standard MRI interpretation.
- Completion meniscectomy is a viable treatment for persistent knee locking due to unstable meniscus remnants.