Knee Dislocation KazNMU 2 топ

Anatomy: Tibiofemoral Joint

Stabilizers: Ligaments Joint capsule Menisci Musculotendinous units

Vascular Anatomy Nerves

Knee Dislocation–Multiligamentous Injury Disruption of normal relationship of tibiofemoral joint Usually requires the injury to 2 of the 4 major groups of ligaments

Pathomechanics

Ligamentous Injury in Polytrauma Patient Suspect & Examine in any Lower extremity long bone fracture Polytrauma Head injury Isolated femoral shaft fx Associated knee ligament injury: 33% (Walling AK 1982) Isolated tibial shaft fx Associated knee ligament injury: 22% (Templeman DC 1989) Ipsilateral Femoral & tibial shaft fx Associated knee ligament injury: 32-53% (Szalay MJ 1990, vanRaay JJ 1991)

Diagnosis l Hyperextension l Popliteal ecchymosis l Vascular insufficiency l Peroneal nerve deficit l Diffuse tenderness but Absence of hemartrosis (capsular disruption) We can observe several signs:

Physical Examination Evaluate soft tissues Puckering Irreducible dislocation

Vascular Examination ~20% (5-30%) of all dislocations Color, temperature, pulses Dorsalis Pedis a. & Tibialis Posterior a. ABI (Ankle Brachial Index) 0.9: Serial examination <0.9: further study/exploration Reduce if dislocated and reexamine ABI 0.9 & no signs of vascular injury: Arterial study may not be necessary if Serial examination q 2-4 hrs for 48 hrs can reliably be performed If not, arterial study may be ordered to r/o vascular injury ABI <0.9 OR Temperature, Color, OR Expanding swelling (hematoma) around the knee

Neurologic Examination Common peroneal nerve palsy Incidence ~20% (10-40%) Most Common with varus injury Usually axonothmesis PROGNOSIS is POOR Complete recovery ~ 20% Peroneal Nerve Motor: EHL, Tib. Anterior, Peroneals Sensory: dorsum of the foot and 1 st web space Tibial Nerve Motor: FHL, Gastrosoleus, Tib Posterior Sensory: Plantar surface and lateral border of the foot

Examination of Ligaments Lachman Test Varus Stress test (20-30 extension) Dont overdo: iatrogenic peroneal nerve palsy !) Valgus Stress Test (20-30° extension)

Examination of Ligaments Posterior Drawer test External Rotation Recurvatum test Dial test (at 30° and 90°) (positive if 10-15° difference)

Examination of Ligaments Injury Severity: based on the difference of contralateral knee Grade I: <5 mmSprain Grade II:5-10 mmPartial tear/avulsion Grade III:>10 mm Complete tear/avulsion

Positive Ligamentous Tests Varus 30° LCL Varus stress in Extension 30° LCL/PLC & Cruciate (ACL/PCL) Valgus 30° MCL Valgus stress in Extension 30° MCL & Cruciate (PCL/ACL) Lachman ACL

Positive Ligamentous Tests Posterior Drawer or Quad 90° PCL Posterolateral 30° PLC Posterolateral 90° 30° PCL and PLC External Rotation Recurvatum test PLC and PCL Dial 30° PLC Dial 30° 90° PLC and PCL

Imaging Plain X-ray Arteriogram Angiography CT Angio MRI CT scan Avulsions ( better detail) Associated fractures (distal femur, proximal tibia) CT Angio

Imaging - Plain X-ray Plain x-ray : AP and Lateral Abnormal joint space Subluxation Associated Fractures (prox tibia, distal femur)

Imaging - Plain X-ray Avulsions Medial epicondyle (MCL) Lateral epicondyle (LCL) Fibular head (LCL) Tibial spine (ACL) Posterior tibial (PCL) Capsular – anteriolateral (Segond)

Imaging - MRI Indicated for ALL multiligamentous injury Gives detail of all non-bony structures Menisci Articular cartilage Ligaments Tendons (biceps, Popliteus, ITB) MR Angiogram (MRA)

Classification - Positional Tibial position with respect to femur Anterior (40%) Posterior (33%) Lateral (18%) Medial (4%) Rotational (5%) Most common: Anterior/Posterior Kennedy JC. 1963

Classification – Injured Structures

Treatment – Closed Reduction Should be done EMERGENTLY/URGENTLY with sufficient muscle relaxation (Dont apply aggressive force!) Closed Reduction In the field In ED Under general anesthesia if not reducible with conscious sedation (Rare as the bony anatomy of the knee is not constrained) Direct force against Popliteal fossa & hyperextension should be AVOIDED

Closed Reduction Maneuver POSITION of DISLOCATION (Tibia relative to Femur) Anterior Traction & elevation of distal femur Posterior Traction & extension of proximal tibia Lateral / Medial Traction & correctional translation Rotational Traction & correctional derotation

Open Reduction Irreducible by Closed methods Rare Typically POSTEROLATERAL Dimple sign – Puckering of anteromedial skin Buttonhole of medial femoral condyle through soft tissues (capsule, MCL, retinaculum, vastus medialis) Watch for skin necrosis Urguden M 2004

Depends on the STABILITY after reduction Stability correlated with the extent of injured structures Knee immobilizer If grossly stable External Fixator If grossly unstable Long leg splint with medial/lateral slabs Does not allow serial checks of vascular status and compartments NEED TO CONFIRM REDUCTION AFTER STABILIZATION (X-ray) Initial Stabilization Complicated by Obesity and Other Injuries

Treatment - Vascular Injury ISCHEMIC LIMB EMERGENCY EXPLORATION Location of injury predictable On table Arteriogram can be done Circulation has to be restored in 6-8 hrs

Treatment – Neurologic Injury Mostly explored & decompressed during repair/reconstruction: Macroscopically normal: Observe In continuity but injured: Observe or Grafting Disrupted: Repair/Grafting 6-12 weeks if not explored and no signs of recovery

Nonoperative Treatment lImmobilization 3-6 weeks – Reevaluate q 2-3 weeks, once stable start ROM lFollowed by ROM in hinged knee brace – with valgus mold in LCL/PLC injury – With varus mold in MCL injury lIsometric exercises as early as possible – Especially quadriceps in PCL injuries

Operative Treatment Variety of techniques No consensus on methods Cruciates: Arthroscopic / Arthroscopic aided Medial and lateral: Open Allografts used for reconstructions Repair capsule

Complications Instability – Residual Laxity Nonoperative tx Failure of reconstruction Easier to treat than stiffness Compartment syndrome Capsule torn: Be very careful with arthroscopy Iatrogenic vascular /nerve injury Osteonecrosis After surgical treatment

Bibliography Bonnevialle P et al. OTRC. 2010;96(1): Engebretsen L et al. KSSTA 2009; 17(9): Fanelli GC et al. Arthroscopy 2002;18:703–714. CD et al. JBJS 2004; 86A; Harner CD et al. JBJS 2004; 86A; l Kennedy JC. JBJS 1963; 45A: l Liow RW et al. JBJS Br 2003:85(6): Meyers MH et al. JBJS 1971; 53A: Mills WJ et al. JOT. 2003;17(5):