MIN TKA

Minimal Incision Total Knee Arthroplasty

New Technique in Surgical positioning

Peter M. Bonutti, MD

Bonutti Orthopedic Clinic, Effingham, IL


Results


Post-operative radiographs showed good alignment and position.  Exceptions included two femoral components in slight flexion, one tilted patella, and one notched femur.

Postoperatively, 90 flexion was obtained by 18 of 20 patients by the third postoperative day.  Discharge average was third postoperative day


Discussion


Total Knee Arthroplasty techniques are evolving with minimal incision arthroplasty posing several potential advantages including:  1) Limited Incision;  2) Reduced Trauma to the Extensor Mechanism;  3) Improved posterior joint exposure;  4) Enhanced collateral ligament balancing in flexion.

MIN TKA with the Suspended Leg technique uses the knee in flexion during the bulk of the procedure through and incision that is two times the patellar length or approximately 9 cm.  With the knee in flexion landmarks are easier to expose, the skin is stretched, and the patella can easily be retracted laterally utilizing a VMO snip of 1 cm.  Superior capsulotomy is simplified and the quadriceps mechanism is elevated rather than released during the exposure.  Sequential flexion or extension of the knee allows exposure of the joint and progressive relaxation of the retractors, either medially or laterally allows enhanced exposure as needed to the joint.  Elevation of the quadriceps mechanism permits satisfactory exposure of the anterior joint without extensive damage to the quadriceps mechanism.

The limited incision technique can be performed with a standard leg holder similar to arthroscopic knee approach with the hip in slight flexion and novel sterile draping technique to ensure a mobile sterile field.  This approach can be used for Arthroscopy to Unicompartmental to Total Knee Arthroplasty.  It may be considered a universal positioning for knee surgery.  Computer Assisted Navigation may assist in optimizing alignment and bone cuts.

Computer Navigation

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Incision Size Comparison

Traditional Incision

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Minimal Incision

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Conclusion


Although these results are preliminary, the Suspended Leg Technique may be a viable option for MIN TKA.  The technique is evolving, and there is a definite learning curve.  Improved instrumentation should reduce the risk of complications.  Further study and evaluation of the Suspended Leg Technique is recommended, but may be a future direction for minimally invasive total knee arthroplasty.



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