Recognizing The Impact Of Bone Marrow Lesions On Treatment Decisions

Arthritis is a multifactor process in which we often see the articular cartilage as the center of pathology. However, other influences such as the synovium, supportive soft tissues (ligaments, muscles, tendons and capsules), anatomic position or alignment, and the subchondral bone and marrow play important roles in disease progression.

The fundamental goal of the treatment of lower extremity joints is to stave off arthritis and preserve motion.

Ankle sprains are one of the most common injuries we see in our office. Reportedly, upward of 45 percent of athletic injuries are attributed to ankle sprain and an estimated 28,000 ankle sprains occur daily.¹ In conjunction with ligamentous damage, bone contusion and subsequent subchondral bone marrow lesions (sometimes referred to as bone marrow edema) occur concomitantly. Bone impaction results in hemorrhage, edema, stress reaction and trabecular microfractures.² When magnetic resonance imaging (MRI) reveals bone marrow lesions, one should consider treatment of this finding in addition to treatment protocols for ligamentous findings. In some instances, the bone marrow lesion level, intensity and location can take treatment precedence over the soft tissue injury. These lesions are present in the ankle (talocrural) joint as well as the subtalar joint, midfoot joints and at the metatarsophalangeal level, depending on the mechanism of injury.

The subchondral bone is a very dynamic layer of tissue in the ankle that normally responds to stress by increasing its bone density and mineralization in order to absorb most of the mechanical forces and share load. As we see in cases of knee osteoarthritis (OA), repetitive stress and/or a reduced healing ability can lead to abnormalities within the subchondral bone.³ The presence of bone marrow lesions strongly correlates to increased pain in patients suffering from arthritis, chronic pain, non-resolution of bone marrow edema and potential subchondral bone and cartilage subsidence.⁴ Persistent subchondral defects and bone marrow lesions can worsen the progression and prognosis of OA and furthermore, research has shown that bone marrow lesions are associated with greater risk of joint replacement.^5-7

Histologic and MRI analysis of bone marrow lesions have identified areas with less mineralization, increased fibrosis, necrosis and microfractures. Authors have compared bone marrow lesions to a non-healing chronic stress fracture.⁵ These lesions signify a precursor of advancing cartilage destruction, subchondral bone erosion and acceleration of joint deterioration by joint collapse, creating a weak foundation for the cartilage.³

Next time you order MRI for the ankle, do not just read the report or assess the soft tissue structures but take a look at the bone as well. Bone marrow lesions are visible as increased signals on T2-weighted images and decreased signals on T1-weighted images.² Gain an appreciation for the various mechanisms of injury a patient may present with, the level of trauma (low versus high impact or force), and the amount of marrow edema that subsequently occurs. Often, the finding of marrow edema will change your treatment. Despite a patient having a Grade 1 or 2 ankle ligament sprain, levels of marrow edema may dictate a longer period of immobilization or direct a short course of non-weightbearing activity limitation.

Conservative treatment options for such pathology are limited and include further immobilization, non-weightbearing activity and the use of bone stimulation devices. Surgical options mostly consist of retrograde decompression or lesion filling techniques. Lesion filling can occur with either autogenous bone or synthetic allografts (often different forms of nanocrystal or porous calcium phosphate). The goal in either technique is to provide a firm support scaffold for the body to replace with natural bone. Post-traumatic marrow edema that presents on MRI with concurrent symptomatic pain to the particular area for more than three months following trauma is a pathological state and a reason for treatment.²

Our preferred treatment is synthetic allograft retrograde filling of the lesion, which is often offered as a “conservative surgical” option, which still allows for further surgical options at a later time if required. This approach allows a quick return to weightbearing and retains joint mobility. A recent study of a similar technique with respect to knee arthritis and associated bone marrow lesions showed that this method delayed the need for knee replacement by at least two years in 70 percent of patients.⁵ By reinforcing the trabecular bone with this scaffold material, the bone receives the structural integrity to heal from within and subsequently gives the cartilage a strong foundation to rest over.

Li, Madry and their respective colleagues conducted a good review of the science and importance of subchondral bone and disease, while Rio and coworkers provided a review of bone marrow lesion patterns (normal versus pathologic) in the hindfoot.^2,8-9

Dr. Hood is a fellowship trained foot and ankle surgeon. Follow him on Twitter at @CRHoodJrDPM.

References

1. Kaminski TW, Hertel J, Amendola N, et al. National athletic trainers’ association position statement: conservative management and prevention of ankle sprains in athletes. J Athl Train. 2013;48(4):528-545.

2. Rios AM, Rosenberg ZS, Bencardino JT, Rodrigo SP, Theran SG. Bone marrow edema patterns in the ankle and hindfoot: distinguishing mri features. Am J Roentgenol. 2011;197(4):720-729.

3. Hunter D, Gerstenfeld L. Bone marrow lesions from osteoarthritis knees are characterized by sclerotic bone that is less well mineralized. Arthritis Res Ther. 2009;11(1):R11.

4. Bassiouni HM. Bone marrow lesions in the knee: the clinical conundrum. Int J Rheum Dis. 2010;13(3):196-202.

5. Cohen SB, Sharkey PF. Subchondroplasty for treating bone marrow lesions. J Knee Surg. 2016; 29(7):553–63.

6. Farr J, Cohen SB. Expanding applications of the subchondroplasty procedure for the treatment of bone marrow lesions observed on magnetic resonance imaging. Oper Tech Sports Med. 2013;21(2):138-143.

7. Sharkey PF, Cohen SB, Leinberry CF, Parvizi J. Subchondral bone marrow lesions associated with knee osteoarthritis. Am J Orthop. 2012;41(9):413-417.

8. Li G, Yin J, Gao J, et al. Subchondral bone in osteoarthritis: insight into risk factors and microstructural changes. Arthritis Res Ther. 2013;15(6):223.

9. Madry H, van Dijk CN, Mueller-Gerbl M. The basic science of the subchondral bone. Knee Surgery Sport Traumatol Arthrosc. 2010;18(4):419-433.