Reconstructing the Extensor Mechanism Following TKR
At ICJR’S Pan Pacific Orthopaedic Congress, Dr. Arlen Hanssen demonstrated his surgical technique for extensor mechanism reconstruction following total knee replacement, providing tips and describing pitfalls associated with this reconstructive method. Below is the abstract he provided for the session.
By Arlen D. Hanssen, MD
Extensor mechanism disruption associated with total knee replacement (TKR) is an uncommon but potentially disastrous complication. Suture fixation has been reported to be insufficient, while autograph and allograft tendon reconstruction techniques have had variable results especially with long-term follow-up.
A simple, straightforward technique using synthetic mesh has been utilized since 1995, for both quadriceps and patellar tendon disruptions associated with TKR. This technique appears reliable and is very cost effective.
The surgical technique includes the use of a knitted monofilament high-density polypropylene graft to reconstruct the extensor mechanism and facilitate fixation of adjacent host tissue into the graft. The graft is placed in an intramedullary position in the tibia, located behind the tibial tubercle and in front of the tibial prosthesis. Graft fixation is accomplished with the use of bone cement and a transfixion cancellous bone screw into the tibial plateau.
One of the most important aspects of this reconstruction is to adequately immobilize the two halves of the extensor mechanism on the ventral and dorsal surfaces so that the extensor mechanism can be drawn distally and allow the vastus medialis (VM) to also overlap the underlying mesh and vastus lateralis (VL).
Once the quadriceps is mobilized, the mesh graft is passed from inside-out through a portal in the lateral retinacular tissues. The graft is then secured to the ventral surface of the VL with a Krackow #5 nonabsorbable suture, which creates the base for attachment of the VM in a distally and laterally tensioned position.
The final construct is then a “pants-over-vest” advancement so that the mesh is sandwiched between the VM and VL.
Postoperative rehabilitation starts with the use of a long leg cast for 10 to 12 weeks followed by progressive range of motion with a brace over the next 3 months.
Dr. Hanssen’s presentation can be found here.
Arlen D. Hanssen, MD, is from Mayo Clinic, Rochester, Minnesota,
- Browne JA, Hanssen AD. Reconstruction of patellar tendon disruption after total knee arthroplasty: results of a new technique utilizing synthetic mesh. J Bone Joint Surg Am. 2011 Jun 15;93(12):1137-43