Popliteus strain

Introduction

Popliteus injuries are rarely isolated and are mostly associated with other injuries to the posterolateral corner of the knee, such as lateral collateral ligament, anterior cruciate, posterior cruciate, or meniscus tears. [1]

Clinically Relevant Anatomy

The popliteus tendon unit is unique in that the distal muscle attachment is designated as the insertion point and the proximal (femoral) tendon attachment is designated as the origin. The muscle inserts into the triangular region along the posteromedial metaphysis of the proximal tibia the only line. It forms the bottom of the popliteal fossa. The popliteal tendon enters the knee joint through the popliteal hiatus and inserts on the lateral femoral condyle at the end of the popliteal groove. The major tendon component inserts into the lateral aspect of the vastus The condyles have variable aponeurotic attachments to the posterior horn of the lateral meniscus and the head of the fibula [2]. Insertion of the lateral meniscus retracts and protects the flexed meniscus, but this function has been debated. The femoral insertion is crescent shaped, The superior aspect is concave. [3] The main tendon of the popliteus consists of anterior and posterior fibers [4]. The popliteus is innervated by the tibial nerves (L4-L5 and S1). The popliteal tendon is inside the joint capsule but outside the joint and outside the synovium. [5]

Politeus muscle Function

The popliteus has both static and dynamic functions at the knee joint.

Dynamic Function: During initial flexion of the knee, it initiates and maintains internal rotation of the tibia on the femur (unlocking the knee joint) and prevents anterior dislocation of the femur on the tibia.

It acts as an auxiliary restraint for posterior tibial displacement in PCL-deficient knees and is an important static stabilizer of the posterolateral corner of the knee. [2]

[6]

Mechanism of Injury

1. Contact/Trauma – The tibia on a partially flexed knee is forced to rotate externally onto an extended knee or is forced to hyperextend. [1]
2. Non-contact/non-traumatic injury – tibia is forced to rotate externally with associated varus forces on the immobilized tibia [1]

[7]

Clinical Presentation

• Pain over the lateral joint line
• Pain at the back of the knee
• pain with weight bearing and climbing stairs
• Incomplete Range of motion

Types of Injuries

• Popliteus Tendon Tenosynovitis
• Popliteus Tendon Avulsion
• Popliteus tendon tear (partial/complete)

Differential Diagnosis

1. Biceps femoris tendon strain
2. Lateral meniscus Injury
3. Lateral collateral ligament injury
4. Tibial nerve injury

Diagnostic Procedures

Complete tears of muscles can be recognized clinically, with the exception of the popliteus. It is difficult to determine which structure of the posterolateral complex is damaged, so MRI is the diagnostic tool of choice. [5]

[8]

Diagnostic Test

1. Garrick Test

The patient is seated with both hip and knee flexed to 90°. The patient actively rotates the calf outward, which is resisted by the examiner. A positive test is pain during motion at the popliteus or tendon location.

2. Shoe Removal Maneuver

This test is where the pain is felt when trying to take off the shoe on the opposite side of the affected knee. This move requires the affected leg to internally rotate to reach the heel of the other leg, and can cause pain during the move when the popliteus is injured.

Examination

Clinically affected patients develop unnatural external rotation of the tibia when the knee is flexed. In addition, other general symptoms such as muscle swelling, edema, or hemorrhage are often present [9]

Due to the neurovascular structures overlying it, only a portion of the popliteus can be safely palpated. The attachments on the tibial shaft and the tendons at the femoral condyles are usually palpable.

Posterior Knee Assessment Patients should be assessed in the supine and prone positions. Pain or “fullness” at the back of the knee may be a sign of joint effusion. Active and passive range of motion of the knee should be assessed during flexion extension and tibiofemoral joint motion Manual muscle testing of knee flexion should be performed with the knee joint positioned in neutral and externally rotated. Palpation of the joint line, tendon of the hamstring, gastrocnemius, and popliteus should be performed. Post pull test to check the integrity of the posterior cruciate ligament. The posterolateral rotational stability of the knee should be checked using the reverse pivot shift or dial test with the reverse flexion test. Isolated popliteus injuries do not cause significant posterolateral rotational instability compared with popliteus injuries posterolateral corner of the knee.

[10][11]

Medical Management

1. Treatment of Popliteal Tendonitis
2. Popliteus tendon avulsion – If an isolated popliteus is confirmed by MRI imaging, conservatively manage with long knee braces for early weight bearing and early range of motion for three months. Postponement of popliteal tendon repair with miniscrews or sutures if conservative management fails Anchoring can be performed. [12]
3. Popliteus Tendon Tears – Tears can be treated conservatively or with open surgical procedures such as repair or reattachment using screws or anchors or arthroscopic methods.

Physical Therapy Management

Non-operative Management

Isolated popliteal injuries rarely result in knee instability, and nonoperative management, including early weight bearing and functional rehabilitation, is usually advocated. However, there are no specific protocols for nonsurgical rehabilitation. [1]

Rehabilitation could include :

• Cryotherapy
• Bracing
• Knee range of motion exercises
• Strengthens Gastrocnemius Hamstrings Quadriceps and Popliteus
• Static and dynamic proprioceptive training
• Agility[1]

1. The non-weight bearing exercises shown can be done with or without a resistance band. It externally rotates the hip, activates the glutes and internally rotates the tibia. It should execute fast in the centripetal phase and slow in the The control mode of the eccentric stage.
2. Open chain prone knee flexion, internal tibial rotation using straps
3. Open chain prone knee isometric measurement using manual resistance to tibial internal rotation [13]

[14][15]

Operative Management

• Functional knee support for 2 to 4 weeks after surgery
• Weight-bearing restrictions
• Knee range of motion exercises
• Quadriceps and Hamstrings Set Exercises
• Strengthening the progress of sports proprioception training[1]