Design & Indications

All BioMedtrix BFX Stems are designed to achieve permanent osteointegration fixation (bone in-growth) within six (6) to eight (8) weeks following a Total Hip Replacement procedure.  Certain conditions, such as soft cancellous bone, broaching technique, proper stem sizing, and proximal femoral bone morphology create technical challenges for optimum press fit fixation and increase the risk of potential complications. Though generally avoided with proper surgical techniques and strict patient-owner compliance with prescribed postoperative care, variables described may result in postoperative subsidence of the implanted stem in the femoral canal.

Available as part of the Universal Hip System the BFX Collared Stem is designed to resist subsidence and stabilize the stem for bone in-growth in the early postoperative period.  The stem’s collar is positioned proximomedial and should rest near the calcar cortical bone at the femoral neck resection when press fit is achieved.

Candidates for this stem include large-breed dogs, German Shepherds, and those breeds with a low canal flare index (CFI), or stove-pipe femoral morphology.  Though animals with a low CFI were the original impetus to develop the Collared Stem, this implant may be used regardless of the CFI – even when the CFI is high – because there is no disadvantage to having the collar when proper technique is followed. It is still important that a proper press fit is achieved.  The BFX Collared Stem is not a substitute for an inadequately press-fit stem or suboptimal surgery technique.

Technical Use & System Scope

The Collared Stem is designed to achieve press-fit stabilization with an identical femoral preparation and similar stem insertion technique as is practiced for a collarless BFX EBM Stem.  The Collared Stem is initially placed using the standard BFX surgical technique to achieve proper press-fit and is seated to its desired location within the femur.  Because it is desirable for the Collared Stem to “settle” postoperatively to achieve a more secure press-fit, a small collar-bone gap is preferable after impaction.

For more information regarding the surgical technique and proper use of the collared stem, please refer to the Collared Stem Surgical Technique Details, courtesy of Dr. William D. Liska, Global Veterinary Specialists.  The Technique Details document was updated in June 2017 to include additional clinical details from Dr. Liska following his six (6) years of experience with this stem design during the first 225 consecutive procedures with follow-up using the Collared Stem. These details are available to help surgeons adapt more quickly to the implantation technique but each surgeon is still responsible for making any adjustments to their own unique technique and preferences that work best for them.

The Universal Hip Basic Preparation instrument set contains all instrumentation needed for implantation of the collared stem. The Large Breed instrument set may be required for implantation of the larger stem sizes.

Collared stems, which are available in sizes #6 – #12 (standard and large breed), and the related instrument sets may be purchased by logging in to the Online Store or by emailing your order to  To order implants, surgeons must have attended a Universal Hip workshop and completed the Product Certification program.