Peripheral neuropathies after shoulder arthroscopy: a systematic review.

Purpose: Peripheral neuropathies after shoulder arthroscopy are rare, though likely under-reported. Many resolve spontaneously, but some patients are left with permanent neurological deficits. The purpose of this study was to review the literature to better characterize this patient population, diagnostic tests performed, the timing and type of surgical intervention, and report clinical outcomes. Methods: A systematic literature review was performed. Articles in English were identified from PubMed, EMBASE, and CINAHL in August 2021. Article titles and abstracts were screened for relevance by two authors and discordant abstracts were resolved by the senior author. Data were subsequently extracted from the included articles. Results: Seventeen articles were identified yielding a total of 91 patients. The average age was 53 ± 12 years, and most patients were male (72%). Rotator cuff repair (62%) was the most common procedure performed. A peripheral neuropathy was identified an average of 80 ± 81 days from the index procedure (range, 0-240 days). Most commonly, peripheral nerve injury presented as a mononeuropathy, with the median nerve (39%) and ulnar nerve (17%) affected predominantly. Seventeen percent of patients underwent a secondary surgery at an average of 232 ± 157 days after the index procedure. At the final follow-up, 55% of neuropathies had resolved, 14% partially improved, and 22% showed no clinical improvement. The most proposed etiologies were postoperative immobilization (29%) and intraoperative positioning (20%), but several possible etiologies have been suggested. Conclusions: Peripheral neuropathies after arthroscopic shoulder procedures are rare. While most spontaneously resolve, up to 1 in 5 patients may have persistent neuropathic symptoms. A high index of suspicion should be maintained throughout the postoperative period. When neurologic deficits are identified, patients should undergo a thorough diagnostic workup and be referred to a subspecialist in a timely manner.

Found Down Extremity Compartment Syndrome Secondary to Substance Use: An Observational Multicenter Study.

With the worsening opioid epidemic in America, more patients are developing found down extremity compartment syndrome (FDECS). The purpose of this study was to describe this patient population, including their presenting symptoms, laboratory test results, and clinical outcomes. METHODS: We performed a 2-center retrospective review of adult patients who developed FDECS secondary to substance use from January 2006 to December 2019. Patients were managed operatively or nonoperatively at the surgeon's discretion. Data on patient demographic characteristics, laboratory values, hospital course, and clinical outcomes were collected from electronic medical records. RESULTS: In this study, 91 patients were included: 85 patients were managed operatively, and 6 patients were managed nonoperatively. Most patients were male, and the mean patient age (and standard deviation) was 37 ± 11 years. Opioids were the most common substance used. Patients managed operatively underwent a mean of 4 ± 3 surgical procedures, 44% received a skin graft, 25% developed a wound infection, and 11% underwent limb amputation. Patients managed nonoperatively did not undergo a subsequent fasciotomy or amputation. At a mean follow-up of 2.3 years, persistent weakness (66%), pain (78%), persistent sensory deficits (53%), and contractures (18%) were common. CONCLUSIONS: Patients who develop FDECS secondary to substance use have high surgical complication rates and poor clinical outcomes. We found high rates of wound infection, revision surgical procedures, and amputation, often leaving young adults with lifelong disability. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Substance-Related Found-Down Compartment Syndrome: A Systematic Review.

OBJECTIVE: To characterize the patient population with substance-related found-down extremity compartment syndrome (FDECS) and report on their treatment and outcome. DATA SOURCE: This systematic review was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Articles in English language were identified by searching 3 online databases, EMBASE, PubMed Publisher, and Cochrane Central, in September 2019. STUDY SELECTION: Studies involving substance-related FDECS were included. Exclusion criteria were as follows: patient age <18 years, not original studies, no full text available, technical reports, traumatic acute extremity compartment syndrome, chronic exertional compartment syndrome, and vascular acute extremity compartment syndrome. DATA EXTRACTION: There were 61 studies included with 166 cases of FDECS. Two investigators screened and extracted data independently according to a standardized template. Disagreements were addressed by an attempt to reach a consensus, and involvement of a third reviewer. Studies were quality assessed with "Quality Assessment tool for Case Series Studies." DATA SYNTHESIS: Descriptive statistics were reported using Excel. CONCLUSION: Substance-related FDECS is often occurring in young adults. Data from this review found that most of the patients were already diagnosed with substance use disorders and/or psychiatric disorders. There should be a high index of suspicion of FDECS in patients presenting after prolonged immobilization. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Rotator cuff repair with biological graft augmentation causes adverse tissue outcomes.

Background and purpose - Biological patches can be used to augment rotator cuff tendon repair in an attempt to improve healing and reduce rates of re-rupture. However, little is known about the in vivo tissue response to these patches. We assessed native rotator cuff tissue response after surgical repair and augmentation with 2 commercially available extracellular matrix (ECM) patches. Patients and methods - Patients underwent a rotator cuff repair augmented with either GraftJacket (Wright Medical), Permacol (Zimmer Biomet), or no patch (Control), applied using an onlay technique. A sample of supraspinatus tendon was collected intraoperatively and 4 weeks post-surgery, using ultrasound-guided biopsy. Histology and immunohistochemistry were performed on all samples. Results - The Permacol group (n = 3) and GraftJacket group (n = 4) demonstrated some changes in native tendon ECM compared with the control group (n = 3). Significant disruption of the extracellular matrix of the repaired native supraspinatus, underlying both patches, was observed. The patches did not generally increase cellularity, foreign body giant cell count, or vascularity compared to the control group. 1 patient in the Permacol group had an adverse tissue immune response characterized by extensive infiltration of IRF5+, CD68+, and CD206+ cells, suggesting involvement of macrophages with a pro-inflammatory phenotype. No significant differences in protein expression of CD4, CD45, CD68, CD206, BMP7, IRF5, TGFß, and PDPN were observed among the groups. Interpretation - Histological and immunohistochemical analysis of native tendon tissue after patch augmentation in rotator cuff repair raises some concerns about a lack of benefit and potential for harm from these materials.

Characterizing the macro and micro mechanical properties of scaffolds for rotator cuff repair.

BACKGROUND: Retearing after rotator cuff surgery is a major clinical problem. Numerous scaffolds are being used to try to reduce retear rates. However, few have demonstrated clinical efficacy. We hypothesize that this lack of efficacy is due to insufficient mechanical properties. Therefore, we compared the macro and nano/micro mechanical properties of 7 commercially available scaffolds to those of the human supraspinatus tendons, whose function they seek to restore. METHODS: The clinically approved scaffolds tested were X-Repair, LARS ligament, Poly-Tape, BioFiber, GraftJacket, Permacol, and Conexa. Fresh frozen cadaveric human supraspinatus tendon samples were used. Macro mechanical properties were determined through tensile testing and rheometry. Scanning probe microscopy and scanning electron microscopy were performed to assess properties of materials at the nano/microscale (morphology, Young modulus, loss tangent). RESULTS: None of the scaffolds tested adequately approximated both the macro and micro mechanical properties of human supraspinatus tendon. Macroscale mechanical properties were insufficient to restore load-bearing function. The best-performing scaffolds on the macroscale (X-Repair, LARS ligament) had poor nano/microscale properties. Scaffolds approximating tendon properties on the nano/microscale (BioFiber, biologic scaffolds) had poor macroscale properties. CONCLUSION: Existing scaffolds failed to adequately approximate the mechanical properties of human supraspinatus tendons. Combining the macroscopic mechanical properties of a synthetic scaffold with the micro mechanical properties of biologic scaffold could better achieve this goal. Future work should focus on advancing techniques to create new scaffolds with more desirable mechanical properties. This may help improve outcomes for rotator cuff surgery patients.

Inflammation activation and resolution in human tendon disease.

Improved understanding of the role of inflammation in tendon disease is required to facilitate therapeutic target discovery. We studied supraspinatus tendons from patients experiencing pain before and after surgical subacromial decompression treatment. Tendons were classified as having early, intermediate, or advanced disease, and inflammation was characterized through activation of pathways mediated by interferon (IFN), nuclear factor κB (NF-κB), glucocorticoid receptor, and signal transducer and activator of transcription 6 (STAT-6). Inflammation signatures revealed expression of genes and proteins induced by IFN and NF-κB in early-stage disease and genes and proteins induced by STAT-6 and glucocorticoid receptor activation in advanced-stage disease. The proresolving proteins FPR2/ALX and ChemR23 were increased in early-stage disease compared to intermediate- to advanced-stage disease. Patients who were pain-free after treatment had tendons with increased expression of CD206 and ALOX15 mRNA compared to tendons from patients who continued to experience pain after treatment, suggesting that these genes and their pathways may moderate tendon pain. Stromal cells from diseased tendons cultured in vitro showed increased expression of NF-κB and IFN target genes after treatment with lipopolysaccharide or IFNγ compared to stromal cells derived from healthy tendons. We identified 15-epi lipoxin A4, a stable lipoxin isoform derived from aspirin treatment, as potentially beneficial in the resolution of tendon inflammation.