The Role of MRI in Diagnosing Biceps Chondromalacia

OBJECTIVES: Sisterman described the “Biceps Footprint”, Castagna et al reported on “Chondral Imprints,” and Kuhn et al identified “Humeral Head Abrasions.”([1],[2],[3]) These can be considered types of biceps chondromalacia (BCM), as we define it, which is an attritional lesion on the humeral head, caused by abrasion of the LHBT over time. BCM occurs in two distinct types: “Junctional” or “Medial”. Junctional BCM (Figure 1) is found along the articular margin of the humeral head where the biceps tendon exits the joint. Medial BCM (Figure 2) is found on the anteromedial portion of the articular surface and may result from chronic “incarceration” of the LHBT between the humeral head and glenoid, a dynamic lesion elicited by the arthroscopic active compression test.([4]) The pre-operative assessment of BCM has never been addressed. The purpose of the study was to evaluate the ability of pre-operative MRI to diagnose BCM. METHODS: A retrospective review was conducted looking at preoperative MRI and intra-operative digital photos comparing three groups: 1) patients operated on for painful BLC lesions with demonstrable BCM seen at surgery (n=34); 2) patients operated on for painful BLC lesions without demonstrable BCM seen at surgery (n=21); and 3) patients without clinical BLC pain operated on for shoulder instability (n=29), who were used as a control group against the BLC pain groups. Groups one and two were age matched, both with a mean age of 42 years, while the average age of patients in group 3 was 29. The MRI's were scored once by an orthopedic surgeon, who graded based on presence or absence of a visible lesion, and again by an experienced radiologist, who blindly and independently scored the MRI's based on chondral loss, bone marrow edema, subchondral signal change, and tendinosis or fraying of the biceps tendon. RESULTS: In group 1, 85% of patients had cartilage loss, 64% had subchondral signal changes, and 85% had a pathological signal in the proximal biceps. In group 2, 86% of patients had cartilage loss, 52% had subchondral signal changes, and 81% had a pathological signal in the proximal biceps, even though no BCM was grossly identified at surgery. In group 3, however, only 51% of patients had cartilage loss, 34% subchondral signal change, and 44% pathological signal in the proximal biceps tendon. Groups 1 and 2 were statistically similar to each other, but varied significantly when compared to group 3. This was particularly true with regard to cartilage loss (p=0.004), signal in proximal biceps (p=0.001), and subchondral signal change (p=0.041). CONCLUSION: MRI is a valuable pre-operative assessment tool that can alert the surgeon to the presence of BCM even if such a lesion has not yet become grossly apparent at arthroscopy. BCM characteristics on MRI include abnormal signal in the proximal biceps, subchondral bone, and cartilage loss. MRI findings consistent with BCM should prompt the physician to consider the biceps as the source of the patient's pain. This is especially relevant when differentiating between a labral tear and the LHBT as inciting pathology. It should be noted, for example, that Provencher et al reported 28% of patients with type II SLAP tears, ultimately underwent a biceps surgery for persistent symptoms. ([1]) This study adds to our collective diagnostic acumen related to the biceps labral complex and highlights the utility of preoperative MRI.