## Medial Knee Pain
*(Inner Knee Pain)*
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### Classification according to ICD-10 (selection)
* **M23.2** Degenerative meniscal lesion
* **S83.2** Acute meniscal tear
* **M17.1** Primary medial knee osteoarthritis
* **M25.56** Knee joint pain
* **M76.5** Knee enthesopathy (e.g. pes anserinus syndrome)
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### Definition
Medial knee pain refers to pain predominantly located on the **inner side of the knee joint**. Symptoms may occur during load, movement, or at rest and can result from different structural causes.
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### Common Causes (Differential Diagnosis)
**1. Medial meniscus injury**
* Degenerative or traumatic
* Typical load-related pain, pain during twisting, or locking symptoms
* Common in patients over 40 years, often without a specific injury
**2. Medial knee osteoarthritis**
* Cartilage degeneration in the medial joint compartment
* Start-up pain, load-dependent pain, progressive varus alignment
* Usually gradual onset
**3. Pes anserinus syndrome**
* Irritation of the tendon insertions on the medial tibia
* Common in runners, overweight patients, and those with axis malalignment
* Localized tenderness below the medial joint line
**4. Medial collateral ligament (MCL) irritation or injury**
* Typically caused by valgus stress
* Localized pain along the ligament
* Possible feeling of instability
**5. Bone marrow edema / subchondral stress reaction**
* Visible on MRI
* Deep, poorly localized load-related pain
* Frequently overlooked
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### Predisposing Factors
* Varus or valgus knee malalignment
* Muscle imbalance (quadriceps and hip musculature)
* Overweight
* Training errors
* Pre-existing cartilage or meniscal degeneration
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### Diagnostic Evaluation
* **Clinical examination** (alignment, stability, meniscal tests)
* **Ultrasound** (soft tissues, joint effusion, tendon insertions)
* **MRI** in persistent or unclear cases
* **Weight-bearing X-rays** to assess joint space narrowing (osteoarthritis)
> An MRI alone does not replace a thorough clinical examination.
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### Treatment
#### Conservative Management (first-line therapy)
* Targeted physiotherapy (alignment, strength, mobility)
* Load management instead of prolonged rest
* Regenerative treatment options depending on findings
* **No corticosteroid injections for degenerative conditions**, as they may damage cartilage
#### Surgical Treatment
* Only if a clear structural cause is present
* For example, mechanical locking due to a meniscal tear or advanced osteoarthritis
* Always after a second opinion and failure of conservative treatment
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### Prognosis
With early, cause-oriented management, the prognosis is favorable in most cases. The key principle is **treating the cause rather than only the symptoms**.
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### Disclaimer
This article is intended for informational purposes only and does not replace professional medical evaluation or diagnosis.