The subacromial bursa modulates tendon healing after rotator cuff injury in rats.

Rotator cuff injuries result in more than 500,000 surgeries annually in the United States, many of which fail. These surgeries typically involve repair of the injured tendon and removal of the subacromial bursa, a synovial-like tissue that sits between the rotator cuff and the acromion. The subacromial bursa has been implicated in rotator cuff pathogenesis and healing. Using proteomic profiling of bursa samples from nine patients with rotator cuff injury, we show that the bursa responds to injury in the underlying tendon. In a rat model of supraspinatus tenotomy, we evaluated the bursa's effect on the injured supraspinatus tendon, the uninjured infraspinatus tendon, and the underlying humeral head. The bursa protected the intact infraspinatus tendon adjacent to the injured supraspinatus tendon by maintaining its mechanical properties and protected the underlying humeral head by maintaining bone morphometry. The bursa promoted an inflammatory response in injured rat tendon, initiating expression of genes associated with wound healing, including Cox2 and Il6. These results were confirmed in rat bursa organ cultures. To evaluate the potential of the bursa as a therapeutic target, polymer microspheres loaded with dexamethasone were delivered to the intact bursae of rats after tenotomy. Dexamethasone released from the bursa reduced Il1b expression in injured rat supraspinatus tendon, suggesting that the bursa could be used for drug delivery to reduce inflammation in the healing tendon. Our findings indicate that the subacromial bursa contributes to healing in underlying tissues of the shoulder joint, suggesting that its removal during rotator cuff surgery should be reconsidered.

The Posterior Cranial Vertical Line: A Novel Radiographic Marker for Classifying Global Sagittal Alignment.

OBJECTIVE: To define a novel radiographic measurement, the posterior cranial vertical line (PCVL), in an asymptomatic adult population to better understand global sagittal alignment. METHODS: We performed a multicenter retrospective review of prospectively collected radiographic data on asymptomatic volunteers aged 20-79. The PCVL is a vertical plumb line drawn from the posterior-most aspect of the occiput. The horizontal distances of the PCVL to the thoracic apex (TA), posterior sagittal vertical line (PSVL, posterosuperior endplate of S1), femoral head center, and tibial plafond were measured. Classification was either grade 1 (PCVL posterior to TA and PSVL), grade 2 (PCVL anterior to TA and posterior to PSVL), or grade 3 (PCVL anterior to TA and PSVL). RESULTS: Three hundred thirty-four asymptomatic patients were evaluated with a mean age of 41 years. Eighty-three percent of subjects were PCVL grade 1, 15% were grade 2, and 3% were grade 3. Increasing PCVL grade was associated with increased age (p < 0.001), C7-S1 sagittal vertical axis (SVA) (p < 0.001), C2-7 SVA (p < 0.001). Additionally, it was associated with decreased SS (p = 0.045), increased PT (p < 0.001), and increased knee flexion (p < 0.001). CONCLUSION: The PCVL is a radiographic marker of global sagittal alignment that is simple to implement and interpret. Increasing PCVL grade was significantly associated with expected changes and compensatory mechanisms in the aging population. Most importantly, it incorporates cervical alignment parameters such as C2-7 SVA. The PCVL defines global sagittal alignment in adult volunteers and naturally distributes into 3 grades, with only 3% being grade 3 where the PCVL lies anterior to the TA and PSVL.

The subacromial bursa is a key regulator of the rotator cuff and a new therapeutic target for improving repair.

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. Using a rat to model rotator cuff injury and repair, tenotomy-activated bursa protected the intact tendon adjacent to the injured tendon and maintained the morphology of the underlying bone. The bursa also promoted an early inflammatory response in the injured tendon, initiating key players in wound healing. In vivo results were supported by targeted organ culture studies of the bursa. To examine the potential to therapeutically target the bursa, dexamethasone was delivered to the bursa, prompting a shift in cellular signaling towards resolution of inflammation in the healing tendon. In conclusion, contrary to current clinical practice, the bursa should be retained to the greatest extent possible and provides a new therapeutically target for improving tendon healing outcomes. One Sentence Summary: The subacromial bursa is activated by rotator cuff injury and regulates the paracrine environment of the shoulder to maintain the properties of the underlying tendon and bone.

Rerupture and wound complications following Achilles tendon repair: A systematic review.

Despite the relatively high frequency of Achilles ruptures, there is no general consensus on the optimal treatment method. A general trend toward more patients being treated nonoperatively has emerged recently with the advent of functional rehabilitation. However, much of the recent data on this subject has been highly variable. This systematic review focused on Achilles tendon rupture (ATR) treatment outcomes, with a focus on rerupture and complication rates. This systematic review specifically focused on articles regarding ATR treatment that also included rerupture and complication rates. Treatments were divided into three categories: open minimally invasive, open standard, and nonoperative. Bivariate analyses were performed to compare complication and rerupture rates among pairs of treatment options, as well as between early weight bearing versus immobilization. There was significantly higher complications for minimally invasive compared to nonoperative treatment (risk ratio [RR] = 4.4154; p < 0.05), lower complication rates for minimally invasive compared to open treatment (RR = 0.3231; p < 0.05), and higher complications for open standard compared to nonoperative treatment (RR = 5.6350; p < 0.001). There were significantly lower rerupture rates in minimally invasive compared to nonoperative treatment (RR = 0.4085; p < 0.001), a significantly lower rerupture rate in nonoperative treatment compared to open treatment (RR = 0.2282; p < 0.001), and no significant difference in rerupture rates when comparing minimally invasive to open standard treatment. We found that operative treatment is associated with fewer reruptures and more complications than a nonoperative approach. Minimally invasive surgery appears to be associated with a lower rate of complications than open operative treatment.

Intraoperative Scrub Nurse Handoffs Are Associated with Increased Operative Times for Lower Extremity Orthopaedic Sports Procedures.

PURPOSE: The purpose of this study was to evaluate the effect of intraoperative scrub nurse handoffs on surgical times for arthroscopically-assisted anterior cruciate ligament (ACL) reconstructions and hip arthroscopies. METHODS: A retrospective chart review was done at a major, urban academic medical center for all patients who underwent arthroscopically-assisted ACL reconstructions and hip arthroscopies for femoroacetabular impingement syndrome between May 2014 and May 2020. All ACL reconstructions were performed by 1 of 6 sports medicine fellowship-trained surgeons, and all hip arthroscopies were performed by a single surgeon. Operative times, number of scrub nurse handoffs, surgeon, patient demographics, and procedure-specific information were recorded. The association between patient characteristics and the number of handoffs, as well as the association between patient characteristics and operative times, stratified by scrub nurse handoffs, were calculated. A multivariable linear regression was performed to assess the association between intra-operative handoffs and operative times. RESULTS: Eight hundred twenty ACL reconstructions and 269 hip arthroscopies were identified. Multivariable linear regression demonstrated increasing intraoperative scrub nurse handoffs were associated with increased operative times for all patients. For ACL reconstructions, when including all possible covariates, 1 scrub nurse handoff increased operative times by 21.1 minutes (95% confidence interval [CI]: 15.36 to 26.89; P < .001), and 2+ handoffs increased operative times by 34.2 minutes (95% CI: 26.28 to 42.15; P < .001). For hip arthroscopies, 1 scrub nurse handoff increased operative times by 7.0 minutes (95% CI: 0.31 to 13.74; P = .04). CONCLUSION: Although a causal link cannot be made, intraoperative scrub nurse handoffs were associated with statistically significant increase in operative times for both ACL reconstructions and hip arthroscopies. LEVEL OF EVIDENCE: Level III, retrospective cohort study.