Knee injuries

Knee

History - nature of injury, e.g.. direct, indirect, rotational, presence of locking, giving way. Previous knee problems.

Examination - look, e.g.. wasting, deformity, swelling, bruising.

Feel - effusion, localise tenderness, check stability, popliteal swelling?

Move - check range, exclude locking by comparing extension on both sides - McMurray's test.

X-ray - For AP & Lat views see Ottawa Knee rules below. Additional views should include skyline view for patellar problems and tunnel view for intercondylar area (e.g. loose bodies)

Ottawa knee rule

A knee X-ray series is only required for knee injury patients with any of these findings:

Age ≥ 55
Isolated tenderness of the patella (no bone tenderness of the knee other than the patella)
Tenderness at the head of the fibula
Inability to flex to 90°
Inability to bear weight both immediately and in the ED
(4 steps; unable to transfer weight twice onto each lower limb regardless of limping)

Aspiration

Evidence for aspiration to improve symptoms ? [BestBets]

Indications are: A) Tense haemarthrosis and B)Diagnostic uncertainty

Large effusion or haemarthrosis

Aspirate under full aseptic conditions, unless immediate referral or surgery intended because of severity of injury
If frank blood in the joint:
- Immobilise in POP knee backslab and refer to VFAC
- Refer to senior ED staff or on-call Orthopaedic Team
There is no evidence to support early MRI in acute traumatic knee haemarthoses with normal x-rays [BestBets]

Locked knee

The knee will flex but will not fully extend. Refer to the on-call Orthopaedic Team.

Collateral ligament tear

Tenderness and pain on stressing the ligament. If there is definite laxity and marked bruising/swelling obtain an opinion from EM Duty Doc. Complete ligament rupture can be masked by muscle spasm. If little laxity or pain is evident, refer to the ED physiotherapist.

Possible meniscal tear

If not locked, apply a double tubigrip and provide crutches. Refer ED physio clinic.

Possible torn cruciate ligaments.

ACL clinical

Use the lever test:

Patient supine, knee fully extended
Provider's fist is placed at the level of the tibial tuberosity on the back side of the leg on the bed, thus causing the knee to bend slightly
Downward pressure is applied to the distal femur, thus creating a lever from the patient's leg, with the fist as the fulcrum
If the ACL is intact, the foot rises off the bed (the lever is working), but if the ACL is torn, the foot remains on the bed (the lever is broken)

Lachman & ant. drawer tests are difficult (pain/swelling) & have poor interrater reliability.

Cruciate # Mx

Rest, crutches, physiotherapy referral and GP follow up
ACL rupture patients are not routinely referred to the fracture clinic or orthopaedic follow up as conservative management gives similar functional results to (early or late) surgery [BMJ 2013] Ref

Loose bodies

If symptomatic refer to the orthopaedic clinic.

Anterior knee pain (chondromalacia patellae)

Please refer to the physiotherapy clinic and GP.

Soft tissue knee problems of uncertain cause - refer to ED physiotherapist.

Knee dislocations

Check distal circulation. Refer to the on-call Orthopaedic Team.

Distal femoral and upper tibial fractures

(including osteochondral)- refer to the on-call Orthopaedic Team.

Patellar fractures

If undisplaced apply POP backslab and refer to the Fracture Clinic (CUH referral form)
If displaced, refer to the on-call Orthopaedic Team
Most need internal fixation as quads tone distracts the fragments
Consider prophylactic anticoagulation (e.g. Rivaroxaban) if high risk of VTE/Hx DVT.[BestBets]

Dislocated patella

Usually reduced before presentation - if not, reduce by extending hip (Entonox)
X-ray to exclude fracture
If 1^st episode, treat conservatively in preference to surgery [BestBets]
If 1^st episode, apply cricket bat splint in preference to PoP cylinder [BestBets]
Refer to the VFAC
Consider prophylactic anticoagulation (e.g. Rivaroxaban) if high risk of VTE/Hx DVT.[BestBets]

Osteochondritis Dessicans

Please see anterior knee pain section.

Thromboprophylaxis

In patients immobilised in leg casts:

Consider prophylactic anticoagulation (e.g. Rivaroxaban) if high risk of VTE or prior DVT [BestBets]
As agreed with Orthopaedics in CUH, prophylactic anticoagulation is not required those patients discharged in a backslab

References

Guiraud K, Silvestre G, Bastin C, et al. Higher sensitivity with the lever sign test for diagnosis of anterior cruciate ligament rupture in the emergency department. Arch Orthop Trauma Surg. 2022;142(8):1979-1983 DOI: 10.1007/s00402-021-04154-x
Frobell RB et al. Treatment for acute anterior cruciate ligament tear: five year outcome of randomised trial. BMJ 2013;346:f232

Knee Injuries