Knee Joint Injuries

Knee join is the largest joint in the human body which can easily be injured, specially in sportsmen.

Anatomy Of Knee Joint

It is composed of several elements.

  1. Bones
    • Femur
    • Tibia
    • Patella
  2. Articular cartilage
  3. Meniscus
    • Act as shock absorbers and stabilize the joint 
  4. Ligaments
    • Help to stabilize the join
      • Collateral ligaments (Medial and lateral)
      • Cruciate ligaments (Anterior and posterior)
  5. Tendons
    • Quadriceps tendon
    • Patellar tendon

Types Of Injuries

Most common injuries associated with knee joint includes fractures, disclocation, sprains, tears and ligamental injuries. 

Fracture Of Patella 

  • Mechanism 
    • High energy injury
    • Avulsion fracture
  • Clinical features
    • Pain over the patella
    • Inability to raise an extended leg
    • Palpable gap felt at the level of the fracture
  • Investigations
    • X-Ray of knee joint
  • Treatment
    • Undisplaced fracture – POP cylinder / Cricket cast for 6 weeks
    • Displaced fracture – ORIF with tension band wiring 
    • Comminuted fracture – Patellectomy 
Dislocation Of Patella 
  • Mechanism
    • Direct trauma
    • Severe contraction of quadriceps 
  • Clinical features
    • Genu valgum, tibial torsion and high riding of patella increases the risk 
    • Typically seen displaced laterally
    • Recurrence in 20% of cases
  • Investigations
    • Skyline x-ray views of patella is required 
  • Treatment
    • Reduced by pushing the patella medially while the knee is extended with entanox analgesia
    • After reduction a POP cylinder is applied for 3 weeks followed by physiotherapy

Chondromalacia Patellae / Runner’s knee

  • Pathogenesis
    • Deterioration of the cartilage on the under surface of the patella
    • Risk factors
      • Poor alignment of the joint
      • Repeated stress on the joint (Running, jumping)
      • Direct trauma to the patella
  • Clinical features 
    • Pain in the knee – Walking downstairs or at rest 
    • Grinding or cracking sensation while flexion and extension of the joint
    • Wasting of quadriceps muscle 
  • Investigations
    • X-Ray of knee joint
    • MRI 
  • Treatment
    • Rest
    • NSAIDs – Anti-inflammatory and analgesic effect (Ibuprofen)
    • Physiotherapy – To prevent knee misalignment 
    • Arthroscopic surgery – Lateral release is commonly done

Knee Dislocation

  • Mechanism 
    • High energy injury – Falling from a significant height, RTA
    • Low energy injury – Obese patient tripping while walking or playing sports
  • Clinical features
    • Knee deformity 
    • Knee pain 
    • 50% of cases reduces by itself but typically there is a break in the anterior cruciate ligament, posterior cruciate ligament, and either the medial collateral ligament or lateral collateral ligament
    • Always check for the peripheral pulses of the lower limbs
  • Complications
    • Popliteal artery damage 
    • Compartment syndrome
    • Damage to common peroneal nerve or tibial nerve
  • Types
    • Based on the movement of the tibia with respect to the femur
      • Anterior
      • Posterior (High risk of vascular injury)
      • Lateral
      • Medial
      • Rotatory
  • Investigations
    • Plain X-Ray of knee
    • CT scan 
    • ABPI – Less than 0.9, then do CT angiography
  • Treatment
    • Reduce the knee ASAP
    • Analgesics – Entanox
    • Check neurovascular status – Before and after reduction and check for 24 hours
    • Apply a loose above knee back slab 

Ruptured Anterior Cruciate Ligament

  • Mechanism 
    • High twisting force applied to a bent knee
    • Usually occurs in sportsmen
  • Clinical features 
    • Loud crack 
    • Pain in the knee joint
    • Rapid onset of joint swelling
    • Anterior draw test positive
  • Investigations
    • X-Ray to exclude fracture
  • Treatment
    • Intense physiotherapy
    • Surgery 
    • Poor healing 
Ruptured Posterior Cruciate Ligament
  • Mechanism
    • Hyperextension injuries 
  • Clinical features
    • Pain in the knee
    • Tibia lies posteriorly to the femur
    • Posterior draw test positive
    • Paradoxical anterior draw 
  • Investigations
    • X-Ray to exclude fracture
  • Treatment
    • PRICE as initial management
    • Physiotherapy
    • Surgery

Rupture Of Medical Collateral Ligament

  • Mechanism
    • Leg forced into valgus via force outside the leg
  • Clinical features
    • Pain and swelling in the medical aspect of the knee
    • Joint instability
    • Positive valgus stress test 

Rupture Of Lateral Collateral Ligament

  • Mechanism 
    • Trauma to the inside of the knee
  • Clinical features
    • Pain and swelling in the lateral aspect of the knee
    • Joint instability 
    • Positive varus stress test
Menisceal Tear
  • Mechanism
    • Rotational sports injury (Twisting of a flexed leg)
    • Common in footballers 
  • Clinical features
    • Pain and difficulty to bear weight
    • Delayed onset of knee swelling
    • Joint locking (Patient will develop skills to unlock the knee)
    • Joint line tenderness
    • Recurrent episodes of pain and effusions, often following minor trauma
  • Investigations
    • X-Ray 
    • MRI
    • Arthroscopy (Locked knee)
  • Treatment 
    • PRICE – Initial management 
    • Analgesics  – NSAIDs 
    • Physiotherapy 
    • Locked knee – Require further assessment 
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1 year ago

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