OWL: OCOSH Classification/Trauma/Leg Injuries/Knee Injuries/Knee Ligament Injuries

Anterolateral Rotatory Instability

C.R.Wheeless — 2002-02-04 23:42:35 GMT

- defined as excessive forward rotation of tibial plateau w/ excessive lateral opening of the joint;
- there is excessive internal rotation of tibia on femur in flexion;
- as knee extends, subluxation is reduced by the bony stability, and a jerk is noted which is basis for the pivot shift test;
- disrupted structures:
- disruption of ACL
- disruption of lateral supporting structures;
- LCL
- arcuate complex;
Wheeless' Textbook of Orthopaedics

Anteromedial Instability

C.R.Wheeless — 2002-02-04 23:42:35 GMT

- medial plateau of the tibia rotating excessively forward & externally on femur as the joint opens on the medial side;
- torn structures:
- MCL;
- posterior oblique ligament;
- ACL;
- medial meniscus tear;
Wheeless' Textbook of Orthopaedics

Arcuate Ligament Complex Wheeless

C.R.Wheeless — 2002-02-04 23:42:35 GMT

- includes posterior 1/3 of lateral supporting structures;
- it includes LCL, arcuate ligament, & exension of popliteus;
- posterior 1/3 of the lateral ligamentous complex is reinforced by biceps, popliteus, & lateral head of gastrocnemius;
- LCL:
- extracapsular fibular colateral ligament originates from lateral epicondyle and attaches to the fibular head;
- in approx 15% of pts short LCL is demarcated by presence of fabella confluent with the posterior aspect of LCL;
- arcuate ligament:
- originates on posterolateral aspect of femur inserts distally onto posterolateral aspect of tibia & is reinforced by the biceps tendon;
Wheeless' Textbook of Orthopaedics

Kruzlifix's Homepage

A.Staehelin — 2002-02-04 23:42:35 GMT

Kruzlifix's ACL Homepage. Notes on ACL and PCL surgical technique

Ligaments of Humphrey and Wrisberg Wheeless

C.R.Wheeless — 2002-02-04 23:42:35 GMT

the ligaments of Humphrey and Wrisberg are meniscofemoral ligaments which run from the posterior horn of the lateral meniscus to the lateral aspect of the medial femoral condyle;
- these ligaments are named based on their location in relation to the PCL;
- the anterior meniscofemoral ligament is known as the ligament of Humphrey where as the posterior meniscofemoral ligament is known as the ligament of Wrisberg;
Wheeless' Textbook of Orthopaedics

Oblique Popliteal Ligament

C.R.Wheeless — 2002-02-04 23:42:35 GMT

- passes from insertion of the semimembranous on posteromedial aspect of tibia obliquely & laterally upward to insertion of semimembranosus on the posteromedial aspect of the tibia obliquely & laterally upward toward insertion of the lateral gastroc head;
- it acts as important stabilizing structure on posterior aspect of knee;
- semimembranous helps tighten this structure with contraction;
- when the oblique popliteal ligament is pulled medially and forward, tightens the posterior capsule of the knee;
- this maneuver can be used to tighten the posterior capsule in the posteromedial corner of the knee in surgical repair;
Wheeless' Textbook of Orthopaedics

Pivot Shift Test Wheeless

C.R.Wheeless — 2002-02-04 23:42:35 GMT

- pivot shift assesses degree of incapacitating dysfunction in knee with ACL deficiency and secondary restraint deficiency;
- pivot-shift test reproduces event that occurs when knee gives way becuase of loss of ACL;
- there is a forward subluxation of tibia during sudden change in direction;
- test may also be used to judge the success of ACL reconstruction;
Wheeless' Textbook of Orthopaedics

Posterior Oblique Ligament

C.R.Wheeless — 2002-02-04 23:42:35 GMT

- thickening of the medial capsular ligament attached proximally to adductor tubercle of femur and distally to tibia & posterior aspect of the capsule;
- anatomically this is the third (deep) layer of the medial compartment;
Wheeless' Textbook of Orthopaedics

Postero-lateral Rotatory Instability of the Knee Wheeless

C.R.Wheeless — 2002-02-04 23:42:35 GMT

- is apparent when with stress testing lateral tibial plateau rotates posteriorly in relation to the femur with lateral opening of joint;
- atraumatic type:
- presents as chronic laxity, often with a varus knee deformity;
- this ligamentous laxity often occurs without ACL or PCL laxity;
- traumatic type:
- mechanism: knee hyperextension combined with a varus stress;
- posterolateraly directed blow to the anteromedial tibia with the knee in hyperextension is most common mechanism;
- most often associated w/ either ACL or PCL injury, and is commonly found in knee dislocations
Wheeless' Textbook of Orthopaedics

Valgus Stress Test Wheeless

C.R.Wheeless — 2002-02-04 23:42:35 GMT

Primary vs Secondary Restraints:
- seationing of MCL results in marked valgus instability;
- isolated sectioning of ACL, PCL, LCL, or posterolateral structures does not cause large increases in valgus angulation;
- cutting of MCL + PCL results in more instability than any other combination;
- hence, primary restraint to valgus rotation is MCL, w/ PCL playing a secondary role.
Wheeless' Textbook of Orthopaedics

Varus Stress Test Wheeless

C.R.Wheeless — 2002-02-04 23:42:35 GMT

Torn Collateral Tested in Flexion:
- when tested in flexion which relaxes posterior capsule, same ligamentous laxity will result in a much greater degree of instability;
- at 30 deg flexion, the cruciates are in their most relaxed state, and pathologic laxity palpated is capsular laxity;
- varus instability in flexion:
- role of LCL increases w/ joint flexion, as posterolateral structures become lax;
- w/ joint flexion, resistance by ACL decreases, but large forces are found in PCL at 90 degrees of flexion;
- LCL is primary restraint to varus stress at 5 deg & 25 deg flexion;
- lateral capsular structure provide secondary support;
- iliotibial band & popliteus muscles have dynamic stabilizing role;
- Torn Collateral Tested in Extension:
- intact cruciate ligaments and posterior capsule are taut & little abduction or adduction instability is detectable;
- instability w/ varus or valgus stress testing suggests cruciate ligament disruption in addition to collateral ligament disruption;
Wheeless' Textbook of Orthopaedics