top of page

IO - CORE for Knee Pain



Concepts for consideration: Minimally Invasive biologic and structurally supported treatment of Bone Marrow Lesions/Edemas, Cysts, Insufficiency Fractures and cartilage lesions.


IO-Core procedure:

Treatment technique utilizing biologics to decompress pain inducing lesions, edemas, cysts, insufficiency fractures by introducing high quality autologous biologic material to accelerate and promote healing of damaged subchondral bone and degenerating cartilage.



Bone pathologies resulting from acute or chronic injury, including bone marrow lesions and osteonecrosis of the knee, cause severe pain and disability. Chronic swelling of the bone underneath cartilage is painful and can be a sign of chronic overload. It can also be a sign of lack of oxygen to the bone called avascular necrosis. The majority of these patients progress rapidly from initial diagnosis to total knee replacement surgery.


A) Typical subchondral fracture in the load-bearing area of the medial tibial plateau. Edema (asterisk) extends into the subchondral cortical bone. This image further shows the subchondral fracture line (arrow) and medial meniscus extrusion (thick arrow). (B) and (C) Typical fatigue stress fracture. Notably, edema (asterisk) does not extend into the subchondral cortical bone (arrows) because the meniscuscartilage-subchondral bone unit is preserved. The incomplete fracture line is better characterized on T1-weighted imaging (thick arrow)

Osteoarthritis can be viewed as a group of overlapping disorders, which results mainly in functional joint failure. Symptomatic OA is linked with bone marrow lesions and BMLs patterns from magnetic resonance images (MRI) have been linked with pain and cartilage degeneration (Alliston et al. (2018).


Recent work focusing on the bone–cartilage interface in OA and the deeper underlying bone has revealed that Bone Marrow Lesion development is a crucial step in OA pathogenesis. Bone pathologies resulting from acute or chronic injury, including bone marrow lesions and osteonecrosis of the knee, causes severe pain and disability. The majority of these patients progress rapidly from initial diagnosis to total knee replacement surgery.


When damage persistently exceeds repair or bone is unable to heal with periods of rest or unloading, a chronic bone marrow edema lesion (BME/BML) develops. Felson et al (2001) had shown that patients with painful knee OA were 2.5 times as likely to have BME, compared with asymptomatic subjects.


There is a correlation of chronic bone marrow lesions/ edemas with knee pain and progression of osteoarthritis. These lesions have also been associated with other degenerative conditions such as meniscal tears, cartilage deterioration, subchondral cyst formation, mechanical malalignment, and ultimately progression to arthroplasty (Collins et al. (2013).


Treatment options

Some bone marrow lesions respond to a course of conservative measures, prior to proceeding with surgical intervention.


• Rest, oral non-steroidal anti-inflammatory drugs, physical therapy, low impact activity, and weight loss.

• Unloader bracing can be particularly helpful as these lesions may calm down with decreased load across the joint.

Minimally Invasive

• Injections of corticosteroids and viscosupplementation.


• Arthroscopy, subchondroplasty, debridement, osteotomy, osteochondral defect repair, unicompartmental/total knee arthroplasty.

Mechanical/Structural Support

Standard subchondroplasty (SCP) is a minimally invasive technique in which osteoconductive bone void filler (calcium phosphate) is injected into the subchondral bone that corresponds to the area of bone marrow edema on MRI. The injected bone substitute/Calcium phosphate is intended to stabilize the subchondral bone mechanically and may provide pain relief through bone reconstitution with time.

Concerns with providing calcium phosphate as structural support for treatment of BML’s have been documented in recent studies.

Forced pressurization of the calcium phosphate during delivery can also lead to overfilling the lesion and extrusion into the joint which may cause postoperative pain (Rebolledo et al. (2018).

A recent study by Chatterjee et al., (2015) reported no benefits with calcium phosphate in patients with symptomatic bone marrow edema lesions of the knee and advanced OA.


Fluoroscopy image of PSIS for Bone Marrow

Aspirate and Bone Core Harvesting


High CFU-F Bone Marrow Aspirate


Intact Bone Core

Biological Support

Intraosseous, intralesional injections: Bone Marrow Concentrate rich in stem cells and growth factors are injected into the non-healing insufficiency fracture/lesion, provide biological support of symptomatic, non-responsive BML’s. Bone marrow aspirate/concentrate has been widely used in orthopedic application to treat bone fusion/healing. Autologous Bone Marrow Aspirate (BMA) is a cellular-based graft that contains Mesenchymal Stromal Cells (MSC) and Growth Factors (such as Bone Morphogenic Proteins 2 and 7) that can signal osteogenic and osteoinductive potential to the osteoconductive scaffold. Resulting in the ability of damaged bone to heal.

Core Decompression with Autologous BMA vs Allograft: Good quality data is available to support use of core decompression for treatment of necrotic bone in femoral head (Avascular Necrosis).

The biologic approach has been made to treat these pathologies by performing a core decompression of the lesion and augmenting it with direct application of allograft (demineralized bone matrix), or autograft combined with PRP or bone marrow aspirate. Autograft is a more natural approach for bone repair as it uses the body’s own tissue and eliminates the risk of rejection or complications. Autograft cancellous bone offers osteogenic, osteoinductive and osteoconductive properties to support the bone healing process. Autogenous Iliac Crest Bone Graft (ICBG) has been the “gold standard” in the orthopedic space but, may lead to complications, such as chronic pain, numbness and infection. Allograft is derived from an organ donor and sterilized. The use of allograft runs the potential risk of immune response complications such as rejection or failure to integrate into the tissue. Irradiated allografts have reported to have lower success rate in younger patients as compared to autograft (Shun-LiKan et al (2016).


Core Decompression of bone marrow lesion


Introduction of Bone Core to bone marrow lesion


Introduction of high CFU-F marrow aspirate

IO-Core Procedure

Is the newest treatment progression for osteoarthritic pain associated with Bone Marrow Lesions. This comprehensive and all-natural approach to healing combines a core decompression, an intraosseous injection of autologous BMA, and placement of autologous bone dowel. As previous studies have shown: core decompression will relieve edema and allow healthy blood flow back into the area, Bone Marrow Aspirate Concentrate provides the necessary regenerative cells for osteoinduction, and an intact bone core/dowell provides a healthy scaffold/surface for osteoconduction (new healthy bone growth).

• Core decompression is the procedure that relieves pressure by drilling directly into injury site.


• Studies have shown a strong correlation to the number of CFU-F and positive clinical outcomes. The higher the CFU-F counts in bone marrow samples means stronger clinical outcomes (Hernigou et al (2005).

• Aspirating high quality marrow and combining with a functioning scaffold for transplantation into a bone defect (Bone Marrow Lesion) replicates the body’s natural healing response at the treatment site.


• Intact bone core/dowel is an autograft harvested from the iliac crest or long bone in a less invasive manner. Harvesting an intact bone core avoids donor site morbidity previously associated with ICBG. These grafts integrate better and support the bone modeling process needed for healing. Previous studies have demonstrated that autograft combination with cellular graft bone marrow aspirate (containing high MSC count) better supports bone healing as compared to graft alone.

IO-Core osteochondral defect procedure provides surgeons with the highest quality autologous biologics and technique to treat patients suffering from debilitating pain caused by bone marrow lesions, edemas, cysts, insufficiency fractures associated with acute and/or chronic injuries such as osteoarthritis.



➢ Significant improvements in both pain and function following subchondroplasty through 2 years postoperative follow-up have been reported (Cohen et al. 2016).


➢ Bonadio et al. (2017) reported the sub chondroplasty technique safe and provide significant improvements in pain and functional scores.


➢ Astur et al. (2018) in his meta-analysis concluded that calcium chloride injection to treat bone marrow lesions decreased pain, improved function and a delay in TKA.


➢ A recently published study from Hernigou et al. (2018) reported subchondral autologous bone marrow concentrate was an effective procedure for treating young patients with knee osteoarthritis following secondary ON of the knee related to corticosteroids.


➢ Application of bone marrow aspirate in combination with core decompression surgery (CDS) improves pain and function measures and long-term hip survival in ONFH cases (Hernigou et al.(2009); Gangi, et al. (2011); Daltro, et al. (2015).


➢ Hernigou et al. (2005) percutaneous autologous bone-marrow grafting is an effective and safe method for the treatment of an atrophic tibial diaphyseal nonunion. However, its efficacy appears to be related to the number of progenitors in the graft, and the number of progenitors available in bone marrow aspirated from the iliac crest

All information has been provided by Benchmark Biomedical and is for educational purpose only. This information does not replace a diagnosis that would be determined by a licensed medical professional.


1. Astur et al. (2018) Evaluation and Management of Subchondral Calcium Phosphate Injection Technique to Treat Bone Marrow Lesion. Cartilage. 2018 Apr



2. Bonadio et al. (2017) Subchondroplasty for treating bone marrow lesions in the knee - initial experience. Rev Bras Ortop. 2017 Apr 28;52(3):325-330


3. Chatterjee et al. (2015) Subchondral Calcium Phosphate is Ineffective for Bone Marrow Edema Lesions in Adults With Advanced Osteoarthritis. Clin Orthop Relat Res. 2015 Jul; 473(7):2334-42


4. Cohen et al (2016) Subchondroplasty for Treating Bone Marrow Lesions. J Knee Surg. 2016 Oct;29(7):555-563. Epub 2015 Dec 7.


5. Colon et al. (2015) Assessment of the injection behavior of commercially available bone BSMs for Subchondroplasty® procedures. Knee. 2015 Dec;22(6):597-603


6. Eriksen et al. (2015) Treatment of bone marrow lesions (bone marrow edema). Bonekey Rep. 2015 Nov 25;4:755


7. Farr et al. (2013) Quality of life in patients with knee osteoarthritis: a commentary on nonsurgical and surgical treatments. Open Orthop J. 2013 Nov 13;7:619-23


8. Rebolledo et al. (2018) Hitting the Mark: Optimizing the Use of Calcium Phosphate Injections for the Treatment of Bone Marrow Lesions of the Proximal Tibia and Distal Femur. Arthrosc Tech. 2018 Oct; 7(10): e1013–e1018.


9. Daltro, et al. (2015) Efficacy of autologous stem cell-based therapy for osteonecrosis of the femoral head in sickle cell disease: a five-year follow up study. Stem Cell Research & Therapy 6:110

10. Gangi, et al. (2011) Autologous bone marrow cell implantation in the treatment of non- traumatic osteonecrosis of the femoral head: five year follow-up of a prospective controlled study. Bone. 49(5):1005-9.


11. Felson DT, Chaisson CE, Hill CL et al. The Association of Bone Marrow Lesions with Pain in Knee Osteoarthritis. Ann Intern Med. 2001;134(7):541– 549.


12. Hernigou, et al. (2009) Cell therapy of hip osteonecrosis with autologous bone marrow grafting. Indian J Orthop. 2009 Jan-Mar; 43(1): 40–45.


13. Collins et al. (2016) Bone Marrow Edema: Chronic Bone Marrow Lesions of the Knee and the Association with Osteoarthritis. Bull Hosp JT Dis (2013). 2016 Mar;74(1):24-36.


14. Wang et al. (2018) Knee pian as a predictor of structural progression over 4 years: data from the Osteoarthritis Initiative, a prospective cohort study. Arthritis Res Ther. 2018 Nov 6:20(1):250


15. Shun-Li Kan et al.(2016) Autograft versus allograft in anterior cruciate ligament reconstructio:A meta-analysis with trial sequential analysis.Medicine (Baltimore). 2016 Sep; 95(38): e4936


16. Alliston et al. (2018) Bone marrow lesions in osteoarthritis: What lies beneath. J Orthop Res. 2018 Jul;36(7):1818-1825.


17. Hernigou et al. (2018) Subchondral stem cell therapy versus contralateral total knee arthroplasty for osteoarthritis following secondary osteonecrosis of the knee. Int Orthop. 2018 Nov;42(11):2563-2571


18. Hernigou et al (2005) Percutaneuous Autologous Bone-Marrow Grafting for Nonunions: Influence of the number and concentration of progenitor cells. The Journal of Bone and Joint Surgery, 2005 July, Voulme 87-A Number 7

bottom of page