Anatomy & Biomechanics

Lateral Collateral Ligament (LCL)

Primary stabilizer to varus opening

Femoral attachment – proximal/posterior to lateral epicondyle

Fibular attachment – midway along lateral fibular head

Popliteus Complex

Important stabilizer to posterolateral rotation

Stabilizer to varus opening

Popliteus attachment on femur

18mm anterior/distal to LCL

anterior fifth of popliteal sulcus

Popliteofibular ligament (PFL)

originates at musculo-tendinous junction of popliteus

attaches at medial aspect of fibular styloid

Mid-Third Lateral Capsular Ligament

Secondary stabilizer to varus opening

Thickening of lateral midline capsule

Meniscotibial portion often injured. Segond injury

Biceps Femoris Complex

Short head of biceps

Long head of biceps

Lateral Meniscus

Injury Mechanism

Rarely isolated injury

Usually as a combined ligamentous injury

ACL/PLC

PCL/PLC

Knee Dislocation

Hyperextension

Varus blow

Noncontact twisting

Importance of injury

Grade III injuries do not heal

Lead to instability and osteoarthritis

Compromise cruciate ligament reconstructions

Diagnosis of LCL/PLC injury

History

Usually due to varus/hyperextension injuries

15 % have a peroneal nerve injury

Usually combined ligamentous injury

Clinical exam

Varus stress test

External rotation recurvatum test

Posterolateral drawer test

Dial test

Reverse pivot shift test

Varus thrust gait

Radiographs

MRI

Arthroscopic evaluation

Treatment for acute posterolateral knee injuries

Acute grade I and II injuries

Brace 6 weeks

Full ROM

Partial weight bearing

Acute grade III injuries

Repair/reconstruct within 2 weeks after injury

Attempt anatomic repair

Each structure repaired individually

Consider augmentation in midsubstance tears

Anatomic reconstruction

Treatment For Chronic Grade III Injuries

Assess for varus alignment

Proximal tibial opening wedge osteotomy

Reassess after 6 months for need for soft tissue reconstruction

Anatomic reconsruction of posterolateral structures

Two tailed reconstruction of LCL, PFLand popliteus tendon

Biomechanically restores function of native ligaments

As a level I trauma hospital, OOU receives an increasing number of knee dislocations. This study evaluates acute knee dislocations seen at OOU from May 1. 1996 through Dec 2004.

Patients and methods: 136 patients with 137 dislocated knees were admitted in the periode. All patients were students or working prior to the injury and all had a high functional level. 50% of the dislocations occured in conjunction with major traffic accidents- the majority of which were motorbikecyklists, while the remaining injuries were sustained during sports. 4 patients had a complete injury of the peroneal nerve on admittance, while an additional 4 had decreased motor strength and \or sensory dysfunction.

In addition one patient had a ruptur of the patellar tendon and one a patella dislocation. Two of the patients in this group had a vascular injury. On admittance the patients underwent a diagnostic exam in the emergency room.. All the patients then had a MRI. The patients were the placed in a brace and on a CPM 2 hours 2 times a day for 7 days, and the vascular status was monitored closely. After 7–10 days the patients underwent surgery including arthroscopic reconstruction of the ACL and PCL with auto or preferably, if available allograft. Results for patient with a followup for more than 6 months are presented including IKDS, Cincinatti, Tegner and a clinical exam with KT1000.

Results:. No serious complication occurred in conjuntion with surgery or the hospital stay. One infection with staf occurred successfully treated. Two patients underwent secondary arthroscopic debridement for arthrofibrosis All the patients have returned to work, but the majority have had to reduce or change their sports activities.

Conclusion:. We have designed a treatment protocol for this difficult patient group. So far the complication frequency has been low.