Evaluating clinical outcomes of two biceps tenodesis techniques: Loop 'N' Tack and subpectoral biceps tenodesis.

Purpose: Biceps tenodesis is an effective surgical procedure that can address pathologies of the long head of the biceps tendon. The purpose of this study was to evaluate clinical outcomes following two different biceps tenodesis techniques: Loop 'N' Tack biceps tenodesis and subpectoral biceps tenodesis. Hypothesis: Patients undergoing both the subpectoral biceps tenodesis and Loop 'N' Tack biceps tenodesis will have improvements in patient-reported outcomes. Methods: Hundred and sixty five consecutive patients who underwent biceps tenodesis were retrospectively identified and contacted by phone to collect visual analog scale pain scores, University of California, Los Angeles shoulder scores, Simple Shoulder Test scores, Single Assessment Numeric Evaluation scores, and American Shoulder and Elbow Surgeons scores. Range of motion, elbow flexion strength, and incidence of bicipital groove pain and Popeye deformity were recorded. Results: One Hundred and forty five patients were included in the study (55 subpectoral, 90 Loop 'N' Tack). Patients in both groups reported high American Shoulder and Elbow Surgeons, Simple Shoulder Test, University of California, Los Angeles, Single Assessment Numeric Evaluation shoulder function scores, low visual analog scale pain scores, and had a minimal risk of complications when measured one year postoperatively. Conclusion: Loop 'N' Tack biceps tenodesis and subpectoral biceps tenodesis techniques are reliable and effective procedures that can reduce pain scores and restore shoulder function when patients require surgical intervention.

Subscapularis Repair Augmentation With the Long Head Biceps Tendon During Anatomic Total Shoulder Arthroplasty: The "Biceps-Subscap Sling" Technique.

Subscapularis repair failure following anatomic total shoulder arthroplasty (TSA) can compromise postoperative range of motion and joint stability, often leading to persistent pain and worse outcomes. Augmenting the subscapularis repair, particularly in at-risk patients, may provide a more robust construct and prevent subscapularis failure. The long head of the biceps tendon (LHBT) is an accessible autograft with applications previously described in several shoulder procedures. In this technical note and accompanying video, we describe LHBT augmentation of subscapularis repair following TSA. The LHBT is released from the supraglenoid tubercle and is passed through the subscapularis tendon vertically in a pulvertaft weave fashion. Transosseous sutures are used to complete the peel repair, with the LHBT acting as a rip-stop to help protect the repair from suture pullout. In addition, the incorporated LHBT remains in continuity with the remainder of the biceps distally and may act as a dynamic stabilizer. This technique, termed the "Biceps-Subscap Sling" technique, provides additional structural integrity to subscapularis repair and is a cost-effective, biologically active option.

Arthroscopic Visualization Is a Reliable Method of Confirming Femoral Button Placement During Anterior Cruciate Ligament Reconstruction.

Purpose: To compare arthroscopic visualization with intraoperative fluoroscopy for confirming proper femoral button placement during ACLR. Methods: Fifty consecutive patients undergoing soft-tissue ACLR between March 2021 and February 2022 were evaluated for inclusion in this study. Both primary and revision ACLR cases using suspensory fixation were included. Surgeons rated their confidence of proper button placement from both an intra-articular perspective (through the femoral tunnel) and an extra-articular perspective (through the iliotibial band) by grading confidence with a Likert scale. Fluoroscopy was also performed for confirmation of proper button placement. Results: Fifty consecutive patients (35.1 ± 14.5 years of age) with soft-tissue ACLR were included. Mean surgeon Likert confidence scores for accurate button placement were as follows: 4.1 of 5 ± 0.9 from an intra-articular perspective, 4.6 of 5 ± 0.7 from an extra-articular perspective, and 8.7 of 10 ± 1.4 based on the sum of intra- and extra-articular perspectives. Fluoroscopic findings demonstrated that 48 of 50 cases had an appropriate flipped button on the lateral cortex of the femur. I total, 2 of 50 had soft-tissue interposition. Cases in which surgeons had high confidence from both intra- and extra-articular perspectives (≥9/10 sum score) were indicative of proper button placement 97% of the time. Conclusions: Arthroscopic visualization is a reliable method of confirming femoral button placement during ACLR and is sufficient to rule out intraoperative fluoroscopy during surgery. ACLR cases with high surgeon confidence from both intra- and extra-articular perspectives (sum score of 9 or greater out of 10) resulted in proper femoral button placement in 97% of cases as confirmed by intraoperative fluoroscopy. Level of Evidence: Level II, prospective cohort study.

Intra-articular Hyaluronic Acid Treatments for Knee Osteoarthritis: A Systematic Review of Product Properties.

INTRODUCTION: There are many intra-articular hyaluronic acid (IA-HA) products on the market that have known intrinsic differences in molecular size, source, and structure. The current review summarizes existing evidence describing and assessing these differences, while also identifying whether these differences have an impact on clinical outcomes. METHODS: This systematic review summarized all literature that specifically addresses IA-HA product differences. Included studies summarized basic science and mechanism of action comparisons of IA-HA product differences, or systematic reviews that assess differences in clinical outcomes between IA-HA product differences. RESULTS: A total of 20 investigations assessed basic science differences between IA-HA products, while 20 investigations provided assessments of the clinical outcome differences between IA-HA product characteristics. The published basic science literature provided a differentiation between low molecular weight (LMW) and high molecular weight (HMW) HA with regard to changes within the synovial fluid, driven by the interactions that these molecules have with receptors in the joint space. These differences in receptor interaction manifest within clinical outcomes, as meta-analyses comparing pain relief after IA-HA suggest that pain reduction is superior in patients who receive HMW HA as opposed to LMW HA. CONCLUSION: This review highlights differences between IA-HA characteristics, and how important the molecular weight, derivation of the product, and structure are to variances in reported clinical outcomes to treat osteoarthritis (OA) of the knee. HMW IA-HAs have shown greater efficacy compared to the alternative of LMW products, while avian-derived and cross-linked products have potentially demonstrated an increase in inflammatory events over non-avian-derived, non-cross-linked HAs.

The long head of the biceps tendon: a valuable tool in shoulder surgery.

ANATOMY AND FUNCTION: The long head of the biceps tendon (LHBT) has different properties and characteristics that render it a valuable tool in the hands of shoulder surgeons. Its accessibility, biomechanical strength, regenerative capabilities, and biocompatibility allow it to be a valuable autologous graft for repairing and augmenting ligamentous and muscular structures in the glenohumeral joint. SHOULDER SURGERY APPLICATIONS: Numerous applications of the LHBT have been described in the shoulder surgery literature, including augmentation of posterior-superior rotator cuff repair, augmentation of subscapularis peel repair, dynamic anterior stabilization, anterior capsule reconstruction, post-stroke stabilization, and superior capsular reconstruction. Some of these applications have been described meticulously in technical notes and case reports, whereas others may require additional research to confirm clinical benefit and efficacy. CONCLUSION: This review examines the role of the LHBT as a source of local autograft, with biological and biomechanical properties, in aiding outcomes of complex primary and revision shoulder surgery procedures.

Biomechanical Evaluation of the Efficacy of Suture Tape Augmentation for Subscapularis Peel Repair.

Background: Failure of a subscapularis repair construct after anatomic total shoulder arthroplasty can result in difficulty with internal rotation and an increased likelihood of dislocation. Although suture tape has been demonstrated to be an efficacious augment for tendonous repairs elsewhere in the body, it has not been investigated as a method for augmenting subscapularis peel repairs. Purpose: To determine the biomechanical efficacy of suture tape augmentation for the repair of a subscapularis peel. Study Design: Controlled laboratory study. Methods: Twelve human cadaveric shoulders underwent a subscapularis peel. Specimens were randomly split into 2 groups: 6 specimens underwent repair using a transosseous bone tunnel technique with 3 high-strength sutures placed with a Mason-Allen configuration (control group), and 6 specimens underwent the control repair using augmentation with 2 suture tapes placed in an inverted mattress fashion and secured to the proximal humerus using a suture anchor (augmentation group). Shoulders underwent biomechanical testing to compare repair displacement with cyclic loading, load at ultimate failure, and construct stiffness. Results: There were no significant between-group differences in displacement after cyclic loading at the superior (P = .87), middle (P = .47), or inferior (P = .77) portions of the subscapularis tendon. Load to failure was significantly greater in the augmentation group (585.1 ± 97.4 N) than in the control group (358.5 ± 81.8 N) (P = .001). Stiffness was also greater in the augmentation group (71.8 ± 13.7 N/mm) when compared with the control group (48.7 ± 5.7 N/mm) (P = .003). Conclusion: Subscapularis peel repair with augmentation via 2 inverted mattress suture tapes secured with an anchor in the proximal humerus conferred significantly greater load at ultimate failure and construct stiffness when compared with a traditional repair using 3 Mason-Allen sutures. There was no difference in repair displacement with cyclic loading between the repair groups. Clinical Relevance: Suture tape augmentation of subscapularis peel repairs after shoulder arthroplasty provides an effective segment to the strength of the repair.

Opioid Requirement After Anterior Cruciate Ligament Surgery: Opioid Use After Anterior Cruciate Ligament Surgery Is Low With a Multimodal Approach, and Fifteen Oxycodone 5-mg Tablets Are Sufficient.

Purpose: To prospectively determine opioid consumption in patients undergoing anterior cruciate ligament (ACL) repair and reconstruction and to develop evidence-based prescription guidelines following ACL surgery. Methods: This multicenter prospective study enrolled patients undergoing ACL reconstruction and repair. Subject demographics and opioid prescriptions were recorded at enrollment. All patients were given education on opiate use and followed the same perioperative, multimodal analgesic regimen. Following surgery, patients were given postoperative "pain journals" to document visual analog scale pain scores and daily opioid consumption for the first 7 postoperative days and on postoperative visit at 14 days. Results: In total, 50 patients were included in this analysis between the ages of 14 and 65 years. Patients were prescribed a median of 15 oxycodone 5-mg pills and consumed a median of 2 pill postoperatively (range 0-19 pills). 38% of patients consumed 0 opioid pills, 74% of patients consumed ≤5 opioid pills, and 96% of patients consumed ≤15 opioid pills. Patients reported a mean daily visual analog scale value of 2.8 of 10; mean satisfaction with pain management was high at 4.1/5 on a Likert satisfaction score. Overall, patients consumed a mean 34% of their opioid prescriptions, leaving 436 opioid pills not consumed. Conclusions: This study suggests that current expert panels may be recommending an excessive volume of opioids. Based on our findings, we recommend that patients be prescribed no more than 15 Oxycodone 5-mg tablets following ACL surgery. Despite this lower volume prescription, mean pain scores remained below 3 of 10, patient satisfaction with pain control remained high, and 66% of opiate medication prescribed was not used. Level of Evidence: II, prospective prognostic cohort investigation.

Approaching Artificial Intelligence in Orthopaedics: Predictive Analytics and Machine Learning to Prognosticate Arthroscopic Rotator Cuff Surgical Outcomes.

Machine learning (ML) has not yet been used to identify factors predictive for post-operative functional outcomes following arthroscopic rotator cuff repair (ARCR). We propose a novel algorithm to predict ARCR outcomes using machine learning. This is a retrospective cohort study from a prospectively collected database. Data were collected from the Surgical Outcome System Global Registry (Arthrex, Naples, FL, USA). Pre-operative and 3-month, 6-month, and 12-month post-operative American Shoulder and Elbow Surgeons (ASES) scores were collected and used to develop a ML model. Pre-operative factors including demography, comorbidities, cuff tear, tissue quality, and fixation implants were fed to the ML model. The algorithm then produced an expected post-operative ASES score for each patient. The ML-produced scores were compared to actual scores using standard test-train machine learning principles. Overall, 631 patients who underwent shoulder arthroscopy from January 2011 to March 2020 met inclusion criteria for final analysis. A substantial number of the test dataset predictions using the XGBoost algorithm were within the minimal clinically important difference (MCID) and substantial clinical benefit (SCB) thresholds: 67% of the 12-month post-operative predictions were within MCID, while 84% were within SCB. Pre-operative ASES score, pre-operative pain score, body mass index (BMI), age, and tendon quality were the most important features in predicting patient recovery as identified using Shapley additive explanations (SHAP). In conclusion, the proposed novel machine learning algorithm can use pre-operative factors to predict post-operative ASES scores accurately. This can further supplement pre-operative counselling, planning, and resource allocation. Level of Evidence: III.

Emerging Treatment Options for Massive Rotator Cuff Tears: Biologic Tuberoplasty, Balloon Arthroplasty, Anterior Cable Reconstruction, Lower Trapezius Transfer.

There are several emerging treatments for patients with massive rotator cuff tears. Biologic tuberoplasty is still in its infancy but holds promise for improving pain and function by biologically covering a bare tuberosity with a dermal allograft to prevent bone-to-bone contact between the tuberosity and the undersurface of the acromion. Balloon arthroplasty is a technique of widespread interest, with the device recently gaining FDA approval. Anterior cable reconstruction uses the autologous long head of the biceps tendon to reconstruct the anterior cable of the rotator cuff. Tendon transfers, specifically lower trapezius tendon transfer, have now been established as a viable option especially in patients who want to regain active external rotation.

Biomechanical evaluation of subscapularis peel repairs augmented with the long head of the biceps tendon for anatomic total shoulder arthroplasty.

BACKGROUND: Subscapularis failure is a troublesome complication following anatomic total shoulder arthroplasty (aTSA). Commonly discarded during aTSA, the long head of the biceps tendon (LHBT) may offer an efficient and cheap autograft for the augmentation of the subscapularis repair during aTSA. The purpose of this study was to biomechanically compare a standard subscapularis peel repair to 2 methods of subscapularis peel repair augmented with LHBT. METHODS: 18 human cadaveric shoulders (61 ± 9 years of age) were used in this study. Shoulders were randomly assigned to biomechanically compare subscapularis peel repair with (1) traditional single-row repair, (2) single row with horizontal LHBT augmentation, or (3) single row with V-shaped LHBT augmentation. Shoulders underwent biomechanical testing on a servohydraulic testing system to compare cyclic displacement, load to failure, and stiffness. RESULTS: There were no significant differences in the cyclic displacement between the 3 techniques in the superior, middle, or inferior portion of the subscapularis repair (P > .05). The horizontal (436.7 ± 113.3 N; P = .011) and V-shape (563.3 ± 101.0 N; P < .001) repair demonstrated significantly greater load to failure compared with traditional repair (344.4 ± 82.4 N). The V-shape repair had significantly greater load to failure compared to the horizontal repair (P < .001). The horizontal (61.6 ± 8.4 N/mm; P < .001) and the V-shape (62.8 ± 6.1; P < .001) repairs demonstrated significantly greater stiffness compared to the traditional repair (47.6 ± 6.2 N). There was no significant difference in the stiffness of the horizontal and V-shape repairs (P = .770). CONCLUSIONS: Subscapularis peel repair augmentation with LHBT autograft following aTSA confers greater time zero load to failure and stiffness when compared to a standard subscapularis peel repair.

Periarticular liposomal bupivacaine mixture injection vs. single-shot interscalene block for postoperative pain in arthroscopic rotator cuff repair: a prospective randomized controlled trial.

BACKGROUND: The pain control efficacy, postoperative opioid requirements, and costs among patients undergoing major shoulder surgery using different perioperative analgesia modalities have been topics of active debate. Several studies have compared periarticular injection (PAI) to interscalene block (ISB) in shoulder arthroplasty, but there is a paucity of data comparing them in arthroscopic rotator cuff repair. METHODS: Patients aged 18-80 years with full-thickness rotator cuff tears and undergoing primary arthroscopic rotator cuff repair at 2 different shoulder centers were screened and subsequently randomized to receive either periarticular injection (PAI) of liposomal bupivacaine mixed with 0.25% bupivacaine (n = 41) or single-shot interscalene nerve block (ISB) (n = 36). Visual analog scale (VAS) pain scores, oral morphine equivalent (OME) use, Single Assessment Numerical Evaluation (SANE) scores, and costs were collected. Differences with P <.05 were considered statistically significant. RESULTS: Day of surgery VAS score and OME usage were significantly reduced with ISB vs. PAI (0.69 vs. 4.65, P < .001, and 18.66 vs. 34.39, P < .001, respectively). There were no significant differences between groups regarding VAS score on postoperative days (PODs) 1-3; however, OME usage on PODs 1 (50.5 vs. 38.8, P = .03) and 2 (48.1 vs. 37.8, P = .04) was significantly more in the ISB group. At POD 3, VAS score (4.13 vs. 3.97, P = .60) and OME use (28.60 vs. 31.16, P = .51) were similar. At 6 and 12 weeks, there were also no significant differences between groups regarding VAS and OME use. There was no difference in SANE score at 12 weeks following surgery between groups and no difference between average 12-week cumulative OME use between groups. The average charge for the PAI was $455, and the average charge for ISB was $745. CONCLUSION: Both ISB and PAI provide acceptable pain control following arthroscopic rotator cuff repair. Patients have less pain on the day of surgery with ISB, but rebound pain is significant after the block wears off, resulting in substantially increased opioid use in the first 2 PODs. However, cumulative opioid use between groups was similar. There were also no significant differences at the end of the 12-week episode of care in any of the other variables studied. The charge per patient for PAI is approximately $300 less than ISB. Thus, PAI may offer surgeons and patients an effective postoperative analgesic modality as an alternative to ISB.

Narcotic requirements after shoulder arthroplasty are low using a multimodal approach to pain.

BACKGROUND: Recent "multimodal" approaches to pain, although understudied, have shown promise in reducing reliance on narcotics in shoulder arthroplasty (SA). Many surgeons report being unsure of how many narcotic pills to prescribe after the surgery. As result, patients are prescribed upwards of 60 oxycodone 5-mg pills for a 6-to-12-week treatment period despite studies showing postoperative pain can be managed without any medication at all. PURPOSE: The purpose of this multicenter study was to prospectively determine the number of opiate pills required after SA to develop generalizable, evidence-based prescription guidelines for surgeons. We hypothesized that opioid prescription would be low using a multimodal approach to pain management. METHODS: The study enrolled 63 patients undergoing SA. Subjects received either an interscalene nerve block with liposomal bupivacaine, standard bupivacaine, or a local infiltration standard bupivacaine field block based on preference. All subjects were provided with postoperative "Pain Journals" to document their daily pain on a Numerical Rating Scale and daily opioid consumption during the 14-day postoperative period. RESULTS: Overall, patients consumed an average of 8.6 oxycodone 5-mg pills (64.5 morphine milligram equivalents) after SA. Seventy-nine percent of patients required 15 or fewer oxycodone 5-mg pills, and 27% successfully managed their postoperative pain with zero opioids. Average pain remained low for patients in all groups. CONCLUSION: With a multimodal approach, most patients undergoing SA can manage postoperative pain with 15 or fewer oxycodone 5-mg tablets, or 112.5 morphine milligram equivalents. The addition of a liposomal bupivacaine interscalene nerve block may further reduce the consumption of postoperative narcotics compared with a standard interscalene nerve block. This study provides evidence that may be used for surgeon guidelines in the effort to reduce opioid prescriptions after SA.

Differences in Patient and Physician Perceptions of Urgency for Musculoskeletal Conditions During the COVID-19 Pandemic.

In 2020, the coronavirus disease 2019 (COVID-19) pandemic limited musculoskeletal care to urgent or "nonelective" office visits and procedures. No guidelines exist to inform patients or physicians what meets these criteria. The purpose of this multi-institutional study was to describe the differences in perceptions of urgency for musculoskeletal complaints between patients and providers during the COVID-19 pandemic. An anonymous survey was distributed to patients who visited the authors' orthopedic clinics in January and February 2020 and practicing orthopedic surgeons. The surveys were administered in May 2020 after COVID-19 was officially labeled a pandemic and included questions regarding demographic information and perceptions of orthopedic urgency. A total of 1491 patients and 128 physicians completed the surveys. A significantly higher percentage of physicians considered the following diagnoses an appropriate indication for an urgent visit compared with patients: fracture (P<.001), acute dislocation (P<.001), infection (P<.001), neurologic compromise (P<.001), tumor (P<.001), acute tendon injury (P<.001), weakness (P<.001), inability to bear weight (P<.001), post-surgical problem (P<.001), and painful joint effusion (P<.001). There were no significant differences in the perception of urgency for the following conditions: bursitis/tendonitis (P=1.00), joint/extremity deformity without pain (P=.113), and loss of range of motion of a joint (P=.467). Younger patients and those with higher levels of education were significantly more likely to consider their conditions urgent. Patients may require additional education to prevent delay in treatment of urgent conditions-especially time-sensitive conditions such as neurologic compromise, tumors, and infections-when access to physicians is limited. [Orthopedics. 2021;44(4):e534-e538.].

Opioid Consumption After Knee Arthroscopy.

PURPOSE: To prospectively observe opioid consumption in patients undergoing knee arthroscopy and to create an evidence-based guideline for opioid prescription. METHODS: This prospective multicenter observational study enrolled patients undergoing outpatient knee arthroscopy for meniscal repair, meniscectomy, or chondroplasty. Patients were provided with a pain journal to record postoperative opioid consumption, Numeric Pain Rating Scale (NPRS) pain scores, and Likert scale satisfaction scores for 1 week postoperatively. State databases were reviewed for additional opioid prescriptions. RESULTS: One hundred patients were included in this study. Patients were prescribed a median of 5 pills (37.5 oral morphine equivalent [OME]). Median postoperative opioid consumption was 0 pills, with a mean of 0.6 pills (4.4 OME), and 74% of patients did not consume any opioid medication postoperatively. All patients consumed ≤5 pills (37.5 OME), and no patient required a refill. Patients reported a mean daily NPRS value of 1.9 out of 10 and a mean Likert score of 4.4 out of 5. CONCLUSION: We found that current opioid prescribing habits exceed the need for postoperative pain management. Overall, all patients consumed ≤5 opioid pills, and 92% of patients discontinued opioids by the second postoperative day. In spite of the low prescription quantity, patients reported high satisfaction rates and low NPRS pain scores and required no refills. Therefore, we recommend that patients undergoing knee arthroscopy are prescribed no more than 5 oxycodone 5-mg pills. LEVEL OF EVIDENCE: II, prospective prognostic cohort investigation.

Opioid requirement after rotator cuff repair is low with a multimodal approach to pain.

BACKGROUND: Current practices may aim to blunt rather than understand postoperative pain. Perhaps the most common serious complication of arthroscopic rotator cuff repair (ARCR) is persistence of opiate medication intake. Patients still receive upwards of 80 oxycodone 5 mg pills, or 600 morphine milligram equivalents (MMEs), leading more than 20% of opioid-naïve subjects to continue to fill opioid prescriptions beyond 180 days after surgery. Developing evidence-based guidelines for narcotic prescription after ARCR presents an opportunity for orthopedic surgeons to address the opioid epidemic. PURPOSE: The purpose of this study was (1) to prospectively determine the requirements for opiate medications after ARCR, and (2) to create an evidence-based guideline for postoperative prescription, in contrast to the anecdotal or expert panel recommendations that currently exist. We further investigated whether a liposomal bupivacaine (LB) interscalene never block (ISNB) would reduce pain and opiate consumption compared with standard bupivacaine ISNB (control) for ARCR. METHODS: The study enrolled 100 patients who underwent primary ARCR surgery. Patients were provided with postoperative "pain journals" to document their daily pain on a numerical rating scale, satisfaction with pain management using the Likert scale, and track their daily oxycodone 5 mg pill consumption during the 14-day postoperative period. Enrolled patients were further randomized to receiving an LB (experimental) or standard bupivacaine (control) ISNB. RESULTS: A total of 77% of all patients required fewer than 15 pills postoperatively. The LB group consumed an average of 1.7 fewer pills (13.0 MMEs) on postoperative day (POD) 1 (P = .02) and reported statistically lower pain during PODs 1 and 2 (P = .01 and P = .006), as well as cumulatively throughout the study period (P = .03). In addition, LB patients remained opioid-free at a higher rate (44% vs. 15% in controls, P = .03). CONCLUSION: With a multimodal approach, the majority of patients undergoing ARCR can manage postoperative pain with 15 or fewer oxycodone 5 mg tablets (112.5 MMEs) and maintain a high degree of satisfaction. The addition of an LB ISNB may further reduce the consumption of postoperative narcotics compared with a standard ISNB. This study provides evidence that may be used for surgeon guidelines in the effort to reduce opioid prescriptions after ARCR.

The interaction between human rotator cuff tendon and subacromial bursal tissue in co-culture.

BACKGROUND: The role of subacromial bursa in rotator cuff pathology is unclear. Along with recognized inflammatory potential, current data demonstrate the presence of mesenchymal stem cells and potential regenerative properties of the bursa. The purpose of this study was to (1) approximate an in vitro co-culture model that represents interaction between torn rotator cuff tendon and subacromial bursa, (2) quantify the cellular activity of tendon and bursa and their interactions, (3) use this model to induce a state of inflammation present with rotator cuff pathology. METHODS: In part 1, tendon and bursa samples were obtained from 6 patients undergoing rotator cuff repair. Tendon and bursa were cultured alone and together in co-culture wells for 21 days. Markers specific for tenocyte gene expression (tenascin C, decorin, etc) were measured in both tendon and bursa alone and compared to co-culture models. In part 2 of the study, an inflammatory state was induced with interleukin-1ß treatment, and markers of inflammation were measured via protein assay at 0 and 21 days in samples from 7 additional patients. RESULTS: There was an increase in tendon and bursa markers in nearly all groups as evidenced by increased gene expression of known tendon and bursa markers. There was a significant increase in gene expression when torn tendon was co-cultured with bursa compared with culturing alone. Additionally, a state of inflammation was induced as evidenced by increased markers of inflammation, inflammatory protein concentration, and inflammatory cells and disruption of histologic morphology. CONCLUSION: There is a clear interaction between rotator cuff tendon and the milieu produced by the subacromial bursa in this in vitro co-culture system that is significantly different when compared to an isolated culture of tendon and bursa. This system was successfully used to induce a state of inflammation that may represent in vivo inflammation. This in vitro model of rotator cuff pathology can aid investigators in testing effects of agents proposed to improve rotator cuff healing. This can lead to further knowledge regarding effective treatment options.

Identification of the Sensory Dependent Locations of the Shoulder Joint to Optimize Surgical Approaches and Reduce Postoperative Pain: A Systematic Review.

INTRODUCTION: Treatment of post-surgical pain is predicated by an understanding of pain generators. The purpose of this review is to identify sensory dependent areas of the shoulder and discuss their correlation in treating postoperative pain. MATERIALS AND METHODS: Pubmed, Embase, and Cochrane Database of Systemic Reviews were searched (key terms: "Nociception" or "sensory pain receptors" or "pain map" or "neuroanatomy and shoulder" or "rotator cuff") to identify studies in the current literature (1966-2018) regarding sensory innervation of the shoulder and rotator cuff. The search was limited to the English language, human studies, and publication types to reviews and clinical studies. Articles written in other languages besides English, animal studies, abstracts, and conference notes were excluded. Each search result was investigated for relevant physiological information of the nerve endings and nociceptors as well as pertinent information and figures that illustrated the location of the identified receptors. RESULTS: A total of 12 articles were identified that addressed the sensory innervation of the shoulder. The shoulder capsule has the highest sensory nerve density. The attachment sites between the labrum and the capsule and glenoid rim were also found to be highly sensory dependent, in contrast to the peri-core zone at the capsulolabral junction, which was found to be less concentrated with fascicles and sensory nerve endings. The subacromial bursa is also a highly sensory dependent structure, with a more concentrated neural network on the coracoacromial side compared to other quadrants of the bursa. Cutaneous locations of sensory fibers on the shoulder are best defined by mapping the pressure pain threshold (PPT) of various locations on the shoulder. The most sensory dependent locations of the shoulder were found to be the posterior border of the acromion, the glenohumeral joint, the anterior deltoid, and the upper trapezius. CONCLUSION: This review examined the origin of pain in the shoulder, the location of cutaneous pain receptors, and receptors in each major part of the shoulder. Providing analgesia to these densely innervated areas of the shoulder can potentially reduce pain associated with surgical trauma. In addition, knowledge of the sensory dependent areas of the shoulder may elicit consideration of alternative incision sites and surgical protocols to decrease the insult to nociceptors in these locations. These changes could possibly decrease the narcotic requirement in the postoperative period.

Determining anatomic accuracy of shoulder field injection: triangular injection technique does adequately reach pain transmitters.

BACKGROUND: Controlling pain after shoulder surgery is a critical component of postsurgical care. Several recent studies have described the use of periarticular, local infiltration anesthesia, and field blocks (FBs) with clinical efficacy after shoulder surgery. The anatomic accuracy and safety of these FBs have not been well described. The purpose of this study was to determine the accuracy of a surgeon performed shoulder field injection. We hypothesized that our field injection would adequately reach the pain transmitters responsible for postsurgical shoulder pain. METHODS: A total of 10 cadaveric specimens were used in the study. A mixture of liposomal bupivacaine, normal saline, and methylene blue totaling 60 cc was prepared. After injection, the specimens were left for 4 hours to allow medication diffusion. The dissection of specimens was performed to identify 4 areas: axillary nerve, suprascapular nerve, supraclavicular nerves, and joint capsule. On dissection, accuracy rates were determined for each area. RESULTS: All 10 cadaveric specimens were injected and dissected to completion. The dissection of the axillary nerve showed methylene blue dye surrounding the nerve in 10 of 10 (100%) specimens, the suprascapular nerve in 9 of 10 (90%), and the supraclavicular nerves in 10 of 10 (100%). Zero of 10 (0%) specimens had any dye penetrate into the glenohumeral joint or capsule. CONCLUSION: The accuracy rates of the injection of the mixture into the shoulder specimens suggest potential to reproduce an FB to the tissues that are responsible for postoperative pain after shoulder surgery. This may represent an option when interscalene nerve block is not desired or contraindicated.

Perioperative pain management for shoulder surgery: evolving techniques.

Improving management of postoperative pain following shoulder surgery is vital for optimizing patient outcomes, length of stay, and decreasing addiction to narcotic medications. Multimodal analgesia (ie, controlling pain via multiple different analgesic methods with differing mechanisms) is an ever-evolving approach to enhancing pain control perioperatively after shoulder surgery. With a variety of options for the shoulder surgeon to turn to, this article succinctly reviews the pros and cons of each approach and proposes a potential pain management algorithm.