Knee Reduction

Indications/Contraindications/Set-Up

Indications: Traumatic Knee Dislocation

Contraindications: No strong contra-indications. Must be cautious with dysvascular or neurologically injured knees and knees with fractures, but urgent reduction is the best bet to improve the NV status of the knee

Relative contraindications: Floating knee (ipsilateral femur and tibia fractures)

Setup

Acquire immobilization, such as knee immobilizer (most common), Bledsoe Brace, or Long leg splint before hand so it can be applied swiftly after reduction

Call for doppler / find doppler prior to sedation

Consent: It is important to explain to the patient that this is an attempt at a reduction and that failure may mean a trip to the operating room for a repeat closed reduction v. open reduction. Additionally, explain the low, but real risk of iatrogenic fracture or nerve injury Order Portable XR knee prior to initiating the sedation event

Technique

Materials: Immobilization (knee immobilizer)

Positioning:

Patient is supine and midline on stretcher.

Assistant is at the thigh on the ipsilateral side at the level of the thigh

You are on the ipsilateral side of the dislocation at the foot.

Technique:

Adequate sedation is critical for any successful reduction. Inadequate sedation risks iatrogenic injury if patient is fighting the procedure

Stand on the injured side such that you can encircle the proximal lower leg in your AC fossa.

Have your assistant pull counter traction on the femur via a flexed hip

In addition to distraction force, may need to apply a valgus or varus moment to recreate the deformity and un-incarcerate any soft tissues

Assess for pulses immediately following event (palpation +/- doppler)

Obtain Ankle Brachial Index (ABI)

Post reduction imaging and protocols

Imaging: Post-reduction AP and Lat XR Knee

-Once reduction completed (restoration of normal contour of the knee / seemingly nml ROM)

-Have rad tech place lead shield on you while you hold the knee stable

-Shoot AP first to grossly gauge the reduction. If appears located, proceed to Lat XR

-Rad tech may resist shooting Lat, but you must persist because need to verify reduction during the sedation event as opposed to stopping sedation to have patient go to XR suite. This may save the patient a 2nd sedation event if the knee if not actually reduced when you think it is

Immobilization: Knee immobilizer, Bledsoe, or Long leg splint

Restrictions: NWB RLE

Post-Reduction Plan: Likely will need to get CTA Knee to assess for injury to the popliteal artery. Patient may also likely need OR for external fixation to further stabilize the knee - does not need to be urgent if NV intact. MRI is helpful to characterize the degree of injury and if desired (attending decision), should be done prior to Ex Fix to avoid issues with Ex-Fix / MRI

Pearls & Pitfalls

Potential complications:
Neurovascular injury is common in this injury and can occur with reduction.
Must be diligent with pre-reduction (Neuro exam, Pulse check, Doppler, ABIs) and post-reduction exam.

Tips for efficiency:
Communicate to the ED team the urgency of this reduction

Perform NV exam on this injury swiftly after learning of it