Project description:Myosteatosis is the pathological accumulation of lipid that occurs in conjunction with atrophy and fibrosis following skeletal muscle injury or disease. Little is known about the mechanisms by which lipid accumulates in myosteatosis, but many studies have demonstrated the degree of lipid infiltration negatively correlates with muscle function and regeneration. Our goal was to identify biochemical pathways that lead to muscle dysfunction and lipid accumulation in injured rotator cuff muscles, a model that demonstrates severe myosteatosis. Adult rats were subjected to a massive tear to the rotator cuff musculature. After a period of either 0 (healthy control), 10, 30, or 60 days, muscles were prepared for RNA sequencing, shotgun lipidomics, metabolomics, biochemical measures, electron microscopy, and muscle fiber contractility. Following rotator cuff injury, there was a decrease in muscle fiber specific force production that was lowest at 30d. There was a dramatic time dependent increase in triacylglyceride content. Interestingly, genes related to not only triacylglyceride synthesis, but also lipid oxidation were largely downregulated over time. Using bioinformatics techniques, we identified that biochemical pathways related to mitochondrial dysfunction and reactive oxygen species were considerably increased in muscles with myosteatosis. Long chain acyl-carnitines and L-carnitine, precursors to beta-oxidation, were depleted following rotator cuff tear. Electron micrographs showed injured muscles displayed large lipid droplets within mitochondria at early time points, and an accumulation of peripheral segment mitochondria at all time points. Several markers of oxidative stress were elevated following rotator cuff tear. The results from this study suggest that the accumulation of lipid in myosteatosis is not a result of canonical lipid synthesis, but occurs due to decreased lipid oxidation in mitochondria. A failure in lipid utilization by mitochondria would ultimately cause an accumulation of lipid even in the absence of increased synthesis. Further study will identify whether this process is required for the onset of myosteatosis.
Project description:Irreparable posterior-superior rotator cuff tear is encountered quite often in clinical practice. Bridging the tendon defect with various materials is reasonable. However, optimal bridging structures and techniques are still being pursued. We introduce a rotator cuff bridging technique, rooting rotator cuff reconstruction. In this technique, autogenous tendon is used to make grafts. On the medial side, the graft tendons are suspended on the rotator cuff tendon. On the lateral side, the graft tendons are placed into tunnels through the tuberosities. The most critical steps of this technique are properly fabricating the humeral tunnels and suspending the graft tendons onto the rotator cuff tendon. We believe this technique will shed light on rotator cuff reconstruction.
Project description:Rotator cuff injuries result in over 500,000 surgeries performed annually, an alarmingly high number of which fail. These procedures typically involve repair of the injured tendon and removal of the subacromial bursa. However, recent identification of a resident population of mesenchymal stem cells and inflammatory responsiveness of the bursa to tendinopathy indicate an unexplored biological role of the bursa in the context of rotator cuff disease. Therefore, we aimed to understand the clinical relevance of bursa-tendon crosstalk, characterize the biologic role of the bursa within the shoulder, and test the therapeutic potential for targeting the bursa. Proteomic profiling of patient bursa and tendon samples demonstrated that the bursa is activated by tendon injury.
Project description:In this study, we collected rabbit supraspinatus muscle tissue with higher temporal resolution (1, 2, 4, 8 weeks)after 8 wk tear followed by repair (n=4/group), to determine time-depenet transcriptional changes after repair. RNA sequencing and analyses were performed using standard techniques to identify a transcriptional timeline of rotator cuff muscle changes and related morphological sequelae.
Project description:The frequency of partial rotator cuff tears is gradually increasing because of the advancements in imaging methods and arthroscopy techniques. One of the repair techniques is repair of the partial rotator cuff tear by conversion to a full-thickness tear. Another technique, the transtendon technique, has some practical challenges and risks. We attempted to develop a practical and easy technique with low morbidity to repair partial tears called the rotator cerclage technique.
Project description:A large to massive rotator cuff tear is a common issue that lacks reliable options to return a patient's range of motion and function when conservative treatment has failed. With up to 96% of massive rotator cuff repairs failing within the first 6 months of repair, surgeons have been searching for a reliable treatment option for this difficult subset of patients. Surgical options for massive, retracted rotator cuff tears include re-establishing the counterforce coupling of the rotator cuff with techniques such as a partial repair or superior capsular reconstruction, preventing superior humeral migration as seen with balloon spacer implantation, and eliminating pain generators with techniques such as biceps tenotomy; however, these do not reconstitute dynamic cuff control. More recently, an acellular dermal allograft, as seen in superior capsular reconstruction, has been used to reconstruct the remaining rotator cuff. We describe a technique using a fascia lata autograft to reconstruct the rotator cuff in the setting of a massive cuff tear. This is of particular importance in centers that lack the funding or institutional approval to use acellular dermal allografts that have been popularized to date.
Project description:Massive rotator cuff tears are particularly challenging to treat and severely limit the function of the shoulder. Compared with a small rotator cuff tear, massive tears are more unpredictable and usually present with low tendon quality. When performing an anatomical repair of the rotator cuff, the surgical treatment is often associated with failure of the construct. An alternative procedure that can be performed in the setting of a massive tear is superior capsular reconstruction (SCR), using an autograft or allograft. This procedure has been shown to be effective and is associated with positive treatment outcomes. Moreover, the combination of an SCR with an anatomic repair of the rotator cuff tendon may provide a stronger fixation for the rotator cuff and ultimately lead to a lower likelihood of retear and failure. The purpose of this Technical Note is to describe our preferred procedure for the treatment of a massive rotator cuff tear through SCR with superimposition of the repair of the native rotator cuff tendons.