Hip Subchondroplasty® Procedure

SCP for the hip is a minimally-invasive, fluoroscopically-assisted procedure that targets and fills subchondral bone defects in the acetabulum and femur through the delivery of AccuFill® Bone Substitute Material (BSM), a nanocrystalline, highly porous injectable calcium phosphate (CaP).

The SCP procedure in the hip is usually performed along with arthroscopy for visualization and treatment of findings inside the joint. In some cases, an open or mini-open procedure is necessary for access to the defect.


Subchondral bone defects filled with bone substitute material during the SCP Procedure may include:

– Chronic bone marrow lesions with/without associated cysts.

– Insufficiency fractures of trabecular bone.

  • Injected AccuFill BSM is replaced with new bone during the healing process.
  • The procedure is usually performed along with arthroscopy to aid in visualization, the SCP procedure does not inhibit the treatment of other findings inside the hip joint when performed along with arthroscopy.
  • Typically an outpatient procedure, so patients generally return home the same day.
  • SCP Procedure does not preclude future procedures. Should it become necessary, future surgery is still an option.

Chronic Bone Marrow Lesions (BML)

The Bone Marrow Lesions (BML) are MRI-visible defects in the subchondral bone. BML can only be seen on fat-suppressed MRI sequences (T2FS, PDFS, etc.) where they appear as a hazy white area against the background of darker bone. Pathologists have shown that BML represent a healing response to trauma such as micro trabecular fractures of the subchondral bone.1

MRI of chronic Bone Marrow Lesions
MRI of chronic Bone Marrow Lesions

In these patients, current treatment guidelines recommend an initial course of conservative care which may heal the defect. If the defect remains, The SCP Procedure may be an option.

During The SCP Procedure, AccuFill BSM, an injectable, flowable, engineered calcium phosphate bone substitute is used to fill a subchondral bone defect. AccuFill BSM crystallizes and hardens in an endothermic reaction at 37° C to form a nanocrystalline, macroporous scaffold in the bone. Over time, through cell-mediated remodeling, AccuFill BSM is resorbed and replaced with new bone.

To learn more about The SCP Procedure, visit the Zimmer Biomet Institute Calendar of Courses for a listing of Seminars and Hands-on Bioskills Workshops.

AccuFill Bone Substitute Material (BSM)

AccuFill BSM is an engineered calcium phosphate mineral compound.2 It flows readily to fill subchondral defects, crystallizes and hardens quickly in an endothermic reaction at 37° C to form a nanocrystalline, macroporous scaffold in the bone. Over time, through cell-mediated remodeling, AccuFill BSM is resorbed and replaced with new bone.

Subchondroplasty Hip AccuFill Preparation Banner

Important Information: The use of AccuFill BSM is not intended to be intrinsic to the stability of the bony structure. Radiographic studies should be used to confirm that the adjacent cortical bone is intact.

AccuFill® BSM Performance





Proprietary next generation apatite.
Mimics chemical structure of human bone.

Facilitates cell-mediated remodeling.


Truly injectable.
Remains cohesive.
Flowable inside cancellous bone.
15 minutes of working time.

No need to remove subchondral bone.
No phase separation from injection pressure.
Interdigitates easily for complete defect fill.
Long window for implantation; intraoperative flexibility.


Endothermically sets in 10 minutes at 37°C.

Sets hard after closure, no thermal necrosis.


Nanocrystalline structure.
65% total porosity; 1-300 μm pore size.
10 MPa compressive strength.

Nanocrystalline structure and high surface area facilitate remodeling and bony ingrowth.
Physical properties comparable to cancellous bone.


Cell-mediated remodeling.
Remodeled vs. dissolved.

Remodels with new bone growth.

AccuFill® BSM = Ca10-x(M)x(PO4)6-x(HPO4,CO3)x(OH)2-x = Bone*2

AccuFill BSM is manufactured by Etex, a subsidiary of Zimmer Biomet and leader in bioresorbable bone substitute materials. The company is headquartered in MIT's University Park in Cambridge, Massachusetts, a world renowned center for biotech research and innovation.

*M = metal ions

Indications and Patient Selection

Indications for Use:

AccuFill Injectable Bone Substitute Material is an injectable, self-setting, macroporous, osteoconductive, calcium phosphate bone graft substitute material that is intended for use to fill bony voids or gaps of the skeletal system of the extremities, spine (i.e. posterolateral spine), and pelvis that are not intrinsic to the stability of the bony structure. These defects may be surgically created osseous defects or osseous defects created from traumatic injury to the bone. AccuFill Injectable Bone Substitute Material is a bone graft substitute that resorbs and is replaced with new bone during the healing process.

Patient Selection

Patients typically present with:

  • Presence of bone defect seen on fat-suppressed MRI (T2FS, PDFS, STIR, etc.)
  • No resolution of BML with conservative care or other intervention

Discuss all treatment options with your patient. All surgical procedures carry a certain level of risk. A complete assessment of possible risks should be discussed before making the decision to have surgery.

Clinical Studies

In an increasingly cost-conscious and data driven healthcare-solutions market, Zimmer Biomet aims to provide high-quality clinical data to demonstrate the safety, effectiveness and value of its products and services.

The Subchondroplasty (SCP®) Procedure is performed using commercially-available devices which are registered and/or cleared by the FDA as is appropriate for the class of the device.

Protocol: A Longitudinal Outcomes Study of the Subchondroplasty Procedure in the Hip

The purpose of this research is to understand the post-operative outcomes of patients choosing to undergo the Subchondroplasty (SCP) Procedure, where subchondral bone defects will be filled in the hip. Subchondral bone defects are abnormal areas of bone in the hip that have been shown to be linked to pain. Patient reported outcomes (PROs) are questionnaires that ask patients about their hip from their point of view both before and after surgery. This study uses a series of PROs to learn how subjects feel about hip pain and function. We expect that patients taking part in this research will participate for approximately 5 years.

This is not a treatment study, but a data gathering study of information before and after surgery. About 100 subjects will take part in this research.

This study is currently active and open to enrollment.

  1. Eriksen EF, Ringe JD. Bone marrow lesions: a universal bone response to injury? Rheumatol Int. 2012;32(3):575–584.
  2. Tofighi, et al. New Generation of Synthetic, Bioresorbable and Injectable Calcium Phosphate Bone Substitute Materials: Alpha-bsm, Beta-bsm and Gamma- bsm; JBBTE. 2009; 2:39.

This material is intended for health care professionals.  Distribution to any other recipient is prohibited.  For indications, contraindications, warnings, precautions, potential adverse effects and patient counseling information, see the package insert or contact your local representative; visit www.zimmerbiomet.com for additional product information.
All content herein is protected by copyright, trademarks and other intellectual property rights, as applicable, owned by or licensed to Zimmer Biomet or its affiliates unless otherwise indicated, and must not be redistributed, duplicated or disclosed, in whole or in part, without the express written consent of Zimmer Biomet.  
Not all products shown herein are available in all regions; check for product country clearances and reference product-specific instructions for use.
Talk to your surgeon about whether joint replacement or another treatment is right for you and the risks of the procedure, including the risk of implant wear, loosening or failure, and pain, swelling and infection. Zimmer Biomet does not practice medicine; only a surgeon can answer your questions regarding your individual symptoms, diagnosis and treatment.