Orthopedic Teaching Cases 2023, Jan, 17 | 12:00 am

4 Sports Medicine CASES

CASE                                4                               

A 54-year-old skier injures his right knee on the last run of the day. He describes getting his ski stuck in the snow and having an immediate onset of pain on the inside of his knee. He did not hear a pop and was able to make his way down the slope under his own power. Over the last few days, the pain has been worse when bearing weight. X-rays are shown in Figure 9–4A–C.

 

 

Figure 9–4 A–B

 

 

 

Figure 9–4 C

 

Which of the following structures provides dynamic stability to the medial knee?

  1. The semimembranosus complex

  2. The sartorius

  3. The gracilis

  4. The semitendinosus

  5. The biceps femoris

 

Discussion

The correct answer is (A). On examination, there is swelling and bruising on the medial knee. He has increased laxity in response to valgus stress at 30 degrees of knee flexion when compared to the contralateral leg. At terminal extension, the valgus stress response is symmetric. His Lachman and anterior drawer tests are symmetric with the left knee.

What is his diagnosis?

  1. ACL rupture with grade 1 MCL sprain

  2. ACL rupture

  3. Grade 2 MCL sprain

  4. Grade 3 MCL sprain

  5. ACL rupture with grade 2 MCL sprain

Discussion

The correct answer is (C). Increased laxity at 30 degrees of knee flexion suggests an MCL sprain (grade 1 or 2). The lack of laxity to valgus stress at terminal extension (0 degrees) is only seen in grade 3 MCL sprains. The symmetric Lachman and anterior drawer tests make an ACL rupture less likely.

Treatment of this injury should include all of the following EXCEPT:

  1. Immediate return to sports

  2. Crutches

  3. Knee immobilizer

  4. Hinged knee brace

  5. Quad strengthening

 

Discussion

The correct answer is (A). The timing for return to sports is related to the severity of the injury. Grade 1 injuries may return in 5 to 7 days. Grade 2 sprains generally require 2 to 4 weeks. Grade 3 injuries can take 4 to 8 weeks to recover. Protected weight bearing with crutches, immobilization, assistive devices, and strengthening can be of assistance.

 

Objectives: Did you learn...?

 

The dynamic stabilizers of the knee?

 

 

The physical examination of MCL injury? The treatment of MCL sprain?