Excellent Results for TM Cones

Cones Excellent results 

Excellent Results for TM Cones
Paper Demonstrates Value of TM Cones in Primary TKR 

 

 

https://zimmerbiometnews.us.newsweaver.com/files/201/1000689/1006354/99206/acc7227abde98b29b79f2a1c/200_tmcones_2.png

 

Large uncontained tibial osseous defects can present a significant challenge for the surgeon performing a primary total knee arthroplasty (TKA). These defects may vary in size, location, and magnitude and may require augmentation in order to restore the joint line and, more importantly, provide support for implant stability

 

Study Design and Method

  • There are currently limited surgical options to address large non contained tibial defects (AORI IIA and IIB) in the primary TKA setting. Techniques for addressing larger defects are often adapted from those utilized in revision TKA.

  • A total of 17 cases (15 patients) in which primary total knee implants and porous tantalum cones were used to address large tibial bony defects.

  • Clinical results were evaluated using Knee Society Scores, pre- and postoperative knee range of motion, and serial radiographs

  • Patients over 66 years old and patients with osteoporosis, with BMI over 35 were excluded for this implant.

  • All procedures were done by a single orthopaedic surgeon who averages approximately 300 TKA per year for greater than 12 years.

  • Bone loss was classified using the Anderson Orthopaedic Research Institute (AORI) system. All 17 knees were either a 2A or 2B.

 

Outcomes

The following results were observed:

  • Seventeen knees, 15 patients, were included in final analysis

  • The average length of follow-up was 3.5 years with a minimum follow-up of two years and maximum follow-up of five years.

  • At the final follow-up all 17 knees had functioning implants and stable metaphyseal cones without radiographic evidence of osteolysis or loosening as evidenced by interface radiolucencies or component subsidence.

  • No patient had signs of instability, infection, or any systemic complications.

  • All 15 patients had excellent post-operative results with an average Knee Society Score of 94.6, improved from an average preoperative score of 19.4.

  • Knee Society Function Scores increased from an average of 41.4 preoperatively, to 78.5 at the minimum twoyear follow-up

  • Knee flexion improved by an average of 12.0° and knee extension improved to neutral in all patients at a minimum two-year follow-up

Conclusions

  • Porous tantalum (TM) cones provide an effective solution when faced with large osseous defects in the primary TKA setting.

  • Porous tantalum cones allow for biological ingrowth and substitution of bone stock due to its inherent structural properties

  • TM Cones were cut in half - it is unknown whether cutting the tantalum cone to custom fit the tibial defect has any resulting effect on its strength and integrity. This should be considered an off label use

  • 17 cases (15 patients) in which primary total knee implants and porous tantalum cones were used – although a small number of patients the authors recognise a larger study is required

  • Key message: Surgeons may question the additional cost of porous tantalum cone augments in these primary TKR patients. However, using TM Cones negates the cost of using a revision tibial implant and that needs to be calculated into a cost saving. This is an excellent clinical paper demonstrating the value of TM Cones in the primary TKR space.

 

Reference
Addressing large tibial osseous defects in primary total knee arthroplasty using porous tantalum cones
Jae S. You a, Anne R.Wright a, Ian Hasegawaa,⁎, Brandon Kobayashi a, MatthewKawaharaa,
Jordan Wang a, Cass K. Nakasonea,b
a Department of Surgery, University of Hawai'i, John A. Burns School of Medicine, Honolulu, HI 96813, United States of America
b Straub Clinic Bone and Joint Center, Honolulu, HI 96813, United States of America

https://doi.org/10.1016/j.knee.2018.11.001