- Sequential Order of Release:
-
PCL: (
posterior stabilized prosthesis is generally required);
-
LCL
- in general, sepquential elevation of the femoral origin of the LCL is performed prior to release of other structures
because LCL elevation will provide the major correction (after release of the PCL);
- if other structures are released beform LCL, there may be overcorrection;
- the main exception to this is when there is resonable extension balance but gross lateral tightness in flexion;
- in this case, release of the
popliteus and lateral capsule is performed prior to release of LCL;
- in some cases, the released ligament may need to be reattached with bone anchors;
- see
varus stress testing;
- lateral retinaculum / posterolateral capsule
- iliotibial tract
-
popliteus
- overly tight popliteal tendon can cause internal rotation of the tibia on the femur with motion;
- externally rotate the tibia on the femur can relax an overly tight popliteus tendon which will lead to an excessive internal
rotational force after surgery;
- in some cases the popliteus tendon will have to be released;
- intramuscular septum
- lateral femoral periosteum
- lateral head of
gastrocnemius
- long head biceps femoris tendon
- Krackow technique:
- type I: (mild)
- 90-95%: little or no medial stretching
- note that a flexion contracture is common with this deformity;
- make sure that there is adequate length in proximal quadriceps capsular incision to facilitate sufficient lateral retraction and eversion of the patella;
- only a few milimeters to at most a centimeter, of bone below the actual joint line needs to be cleared of soft tissue;
- order of release:
-
PCL: (
posterior stabilized prosthesis is generally required);
- posterolateral capsular ligamentous complex
-
LCL,
popliteus;
- typically a medial ligament reconstruction will not be necessary;
- type II: severe
-
PCL: (
posterior stabilized prosthesis is generally required);
- valgus contractures are corrected by reflection of capsule proximally off the femur;
- a significant deformity may require reflection of femoral origin of
LCL;
- after removal of any peripheral osteophytes from the femur and tibia, lateral capsule is elevated to the posterolateral corner;
- if the knee cannot be brought into neutral alignment, the following tissues may have to be sequentially released;
- this is performed inside joint, & band can be easily palpated thru the synovium and tenotomized using cautery;
-
popliteus tendon
- lateral collateral and popliteus tendons should be released at their lateral femoral epicondylar attachments;
-
LCL
- biceps femoris tendon:
- this can be done from inside the joint with care taken to protect the peroneal nerve passing posteriorly;
-
iliotibial band
- in some cases, excessive medial laxity is addressed with medial reefing along with lateral release, but the surgeon should have a
semi-constrained TKR available should instability persist after the trial components are in place;
Effect of selective lateral ligament release on stability in knee arthroplasty.
