Medial Meniscus Tear with MCL Injury
This patient most likely has a medial meniscus tear combined with a medial collateral ligament (MCL) injury, and should undergo initial radiographs followed by MRI to confirm the diagnosis and guide treatment, with most cases managed conservatively through rehabilitation unless there is a posterior root tear with avulsion fracture requiring surgical repair. 1, 2
Clinical Diagnosis
The combination of findings strongly suggests combined pathology:
- Positive bounce home test indicates a meniscal tear preventing full knee extension due to a mechanical block 1
- Positive valgus stress test confirms MCL injury, as this test stresses the medial stabilizing structures of the knee 3, 4, 5
- Medial knee pain localizes the pathology to the medial compartment structures 3, 6, 7
The MCL is the most commonly injured ligament in the knee, reported in 7.9% of all knee injuries, and frequently occurs with meniscal pathology 5
Diagnostic Imaging Approach
Initial radiographs are appropriate as the first imaging study for knee pain to exclude fracture, avulsion injuries, or degenerative changes 1, 8
MRI without IV contrast should be the definitive imaging study when radiographs are negative or non-diagnostic, as it provides superior evaluation of:
- Meniscal tears with sensitivities approaching 88-90% 1
- MCL injury location and grade (superficial vs deep layers) 7, 4
- Associated bone marrow edema or contusions 1
- Cruciate ligament integrity 1
- Posterior root tears with avulsion fractures that may require surgical intervention 2
Treatment Algorithm
For Isolated Grade I-II MCL Injuries:
Conservative management is appropriate for most incomplete MCL tears without meniscal avulsion 3, 4, 5:
- Early rehabilitation with gradual return to activity 3, 4
- Activity modification during healing phase 3
- Bracing may provide symptomatic relief but is not mandatory 1, 3
If persistent pain beyond 6-8 weeks despite conservative treatment, consider deep MCL pathology 7:
- MRI will confirm thickening, scarring, or tearing of the deep MCL 7
- Ultrasound-guided corticosteroid injection into the deep MCL provides excellent outcomes, with 96% of patients returning to sport and 81% maintaining pre-injury function at 20 months 7
For Meniscal Tears:
Conservative management is appropriate for degenerative meniscal tears 2
Surgical repair is indicated for acute traumatic posterior root avulsions with bony fragments 2:
- Delayed treatment leads to irreversible meniscal damage and accelerated joint degeneration 2
- Post-surgical rehabilitation focuses on quadriceps and hamstring strengthening 2
- Long-term monitoring for osteoarthritic changes is necessary 2
For Combined MCL and Meniscal Injuries:
Most Grade I-II MCL injuries with meniscal tears can be treated nonoperatively 3:
- The MCL should be allowed to heal with conservative measures 3, 4
- Meniscal pathology is reassessed after MCL healing if symptoms persist 3
Grade III (complete) MCL tears require careful evaluation to exclude associated injuries requiring surgical treatment 3:
- Surgical treatment may include MCL repair if there are concomitant cruciate ligament injuries requiring reconstruction 3
- Chronic medial knee injuries with persistent instability may require operative reconstruction 3
Critical Pitfalls to Avoid
- Do not assume all medial knee pain is superficial MCL injury - deep MCL pathology causes persistent symptoms and requires targeted injection therapy 7
- Do not delay imaging if posterior root tear is suspected - these injuries accelerate osteoarthritis and require prompt surgical intervention 2
- Do not order MRI prematurely - reserve for cases where surgery is being considered, pain persists despite adequate conservative treatment, or radiographs are normal but symptoms persist 8
- Do not use lateral heel wedges for medial compartment pathology - evidence suggests they may worsen symptoms 1
Rehabilitation Focus
Regardless of treatment approach, rehabilitation should emphasize: