Diagnosis and Management of Partial Thickness Rotator Cuff Tears

A Comprehensive Review

Kevin D. Plancher, MD, MPH; Jaya Shanmugam, MD; Karen Briggs, MPH; Stephanie C. Petterson, MPT, PhD


J Am Acad Orthop Surg. 2021;29(24):1031-1043. 

In This Article

Etiology, Natural History, and Tear Progression

The reported prevalence of PRCTs varies by imaging modality: 15.87% in magnetic resonance imaging (MRI), 17.2% in ultrasonography, and 18.49% in cadaveric studies.[4] Intratendinous tears are the most common tear type, and articular-sided tears are 2 to 3-times more common than bursal-sided tears.[5] A large insurance database study suggests that PRCTs occur most frequently in women and patients aged 65 to 69 years; however, others suggest that the incidence is higher in men.[6] Prevalence estimates may be underrepresented in younger and overhead athletes because not all PRCTs are symptomatic. Del Grande et al[7] reported the MRI prevalence of PRCTs to be 32% among asymptomatic baseball pitcher draft picks. Similar findings have also been reported in collegiate baseball pitchers and professional tennis players.[8]

The etiology of PRCTs is multifactorial and varies by tear location (eg, articular-sided, bursal-sided, and intratendinous). Extrinsic causes are the result of direct compression of the RC tendon against the undersurface of the acromion and coracoacromial ligament as well as mechanical overuse, greater tuberosity fractures, and glenohumeral dislocations. Bursal-sided tears are more commonly associated with subacromial impingement and occur at the tendon–bone interface.[9] Acute trauma, chronic microtrauma from overuse, instability, internal impingement, and intrinsic factors, including age-related histological changes and decreased tendon vascularity, contribute to increased tendon strain at its insertion and resultant degeneration. Articular-sided tears are more common in young athletes and the older patient population and occur more posteriorly at the supraspinatus–infraspinatus interval.[10,11] Intrasubstance tears occur from shear forces on a degenerated tendon and can occur in isolation with an outer bursal and inner articular surface that is intact or in conjunction with articular-sided or bursal-sided tears.

Animal models of partial-thickness supraspinatus and infraspinatus tears suggest that spontaneous healing results in fibrocartilage formation and weaker tendon-to-bone attachment.[12] This poor healing potential may contribute to tear progression, a primary concern when determining optimal treatment.

Keener et al[2] evaluated tear enlargement and progression in 224 subjects with asymptomatic RC tears. Forty-four percent of PRCTs progressed to FTTs at a median of 5.1 years. Forty-six percent developed new pain at a median of 2.6 years. Tear progression was a risk factor for new onset of symptoms with a 1.69-times higher prevalence of pain compared with stable PRCTs. Mall et al[13] reported that 33% of patients with asymptomatic PRCTs became symptomatic at 1.92-year follow-up; 40% of symptomatic PRCTs progressed to FTTs evidenced on ultrasonography.

Maman et al[14] followed up 26 patients with PRCTs treated nonsurgically. At 20-month follow-up, two patients (8%) had tear progression on MRI, 23 patients (89%) exhibited no change, and one patient had a >5 mm decrease in tear size. Kong et al[3] assessed the role of tear location and progression. Eighty-one patients (23 articular-sided and 58 bursal-sided) with high-grade PRCTs (eg, tear involvement >50% mediolateral footprint) underwent MRI evaluation at 19.9 ± 10.9-month follow-up. Thirteen patients (16%) exhibited tear progression (ie, >20% increase in size; two articular-sided, 8.7%; 11 bursal-sided, 19.0%), 48 patients (59%) experienced no change, and improvement (ie, >20% decrease in size) was noted in 20 patients (25%, 9 articular-sided and 11 bursal-sided). Matthewson et al[15] investigated the relationship between tear size and progression. Fifty-five percent of high-grade PRCTs exhibited progression compared with 14% of low-grade PRCTs (ie, <50% tendon thickness). In summary, tear progression can lead to new onset of symptoms and is more likely in tears >50% of tendon thickness.