Management of Acute Rotator Cuff Tears

Use of a Spinal Needle Through the Deep Rotator Cuff Tissue to Treat Rotator Cuff Tears Under Direct Articular Vision

Achieving sufficient attachment of deep rotator cuff tissue to the footprint area on the greater tubercle of the humerus is essential for functional recovery, yet the optimal approach remains uncertain. We introduce a surgical technique for rotator cuff tear repair using a spinal needle to penetrate deep rotator cuff tissue under direct arthroscopic visualization. After trimming the torn edge, an arthroscope is inserted into the joint cavity through a posterior portal, and a hole is drilled into the humeral head cartilage margin using an upper approach, facilitating the implantation of an internal shoulder row nail. A spinal needle is used to introduce a No. 2 polydioxanone (PDS; Johnson & Johnson) line through sufficient deep rotator cuff tissue. Graspers are then used to extract the stitch and PDS together through the anterolateral opening. Once the PDS is knotted, the stitch is introduced into the rotator cuff. This process is replicated to insert additional stitches into the rotator cuff. Our proposed technique, involving a spinal needle under direct visualization, ensures sufficient coverage of the deep rotator cuff tissue over the footprint area and promotes the healing of the repaired rotator cuff. This method is safe, effective, convenient, and reproducible.

Anatomical design and production of a novel three-dimensional co-culture system replicating the human flexor digitorum profundus enthesis

The enthesis, the specialized junction between tendon and bone, is a common site of injury. Although notoriously difficult to repair, advances in interfacial tissue engineering techniques are being developed for restorative function. Most notably are 3D in vitro co-culture models, built to recreate the complex heterogeneity of the native enthesis. While cell and matrix properties are often considered, there has been little attention given to native enthesis anatomical morphometrics and replicating these to enhance clinical relevance. This study focuses on the flexor digitorum profundus (FDP) tendon enthesis and, by combining anatomical morphometrics with computer-aided design, demonstrates the design and construction of an accurate and scalable model of the FDP enthesis. Bespoke 3D-printed mould inserts were fabricated based on the size, shape and insertion angle of the FDP enthesis. Then, silicone culture moulds were created, enabling the production of bespoke anatomical culture zones for an in vitro FDP enthesis model. The validity of the model has been confirmed using brushite cement scaffolds seeded with osteoblasts (bone) and fibrin hydrogel scaffolds seeded with fibroblasts (tendon) in individual studies with cells from either human or rat origin. This novel approach allows a bespoke anatomical design for enthesis repair and should be applied to future studies in this area.

Acute, Traumatic Rotator Cuff Tears Have Smaller Critical Shoulder Angles Than Degenerative Tears

PURPOSE

To determine whether the critical shoulder angle (CSA) in acute, traumatic rotator cuff tears (RCTs) is consistent with the previously described CSA in chronic degenerative RCTs.

METHODS

We performed a multicenter retrospective analysis of 134 patients presenting to 5 surgeons fellowship trained in shoulder and elbow or sports. Preoperative imaging was used to measure the CSA and tear characteristics. Patients were included if they had acute, traumatic full-thickness RCTs documented on advanced imaging and had preoperative Grashey radiographs. Patients were excluded if they had any history of shoulder pain, injury, surgery, or treatment prior to the current episode; were overhead athletes; or had fatty infiltration greater than Goutallier grade 1 on imaging.

RESULTS

The mean CSA was 33.5° (standard deviation, 4.1°), and 60% of tears had a CSA of less than 35°, much below the mean of 38.0° and the threshold of greater than 35° in degenerative RCTs. The mean age was 58 years, and 70% of patients were men. Overall, 60% of tears involved the subscapularis, 49% of tears occurred in patients aged 60 years or older, and 18% of patients sustained a dislocation. Older age (β = 0.316, P = .003) and male sex (β = 5.532, P = .025) were predictive of tear size, and older age (β = 0.229, P = .011) and biceps avulsion (β = 8.822, P = .012) were predictive of tear retraction.

CONCLUSIONS

Acute, traumatic RCTs have CSAs that are 5° smaller than those of degenerative tears, and the majority (60%) have CSAs that are below the threshold consistent with degenerative RCTs. The majority of traumatic tears (60%) involve the subscapularis.

CLINICAL RELEVANCE

The study findings suggest that a traumatic tear is not simply the acute failure of a degenerative tendon and that it represents a distinct pathologic entity. These findings support current practice of treating traumatic RCTs differently than degenerative RCTs.