Bone density and its relation to the development of acromial stress fracture following reverse total shoulder arthroplasty.

Background: Postoperative acromial stress fracture is a troublesome postoperative complication after reverse shoulder arthroplasty. Our study aims to utilize routinely performed preoperative computed tomography scans to identify differences in the material properties of the acromion in patients who did and did not develop a postoperative acromial stress fracture. Methods: Treatment records and computed tomography scans for 99 reverse shoulder arthroplasties were collected. Scans were calibrated using a phantom and transferred for post-processing where the acromion, full scapula, and humeral head were isolated. The final segmented model was used to assess acromial volume and volumetric bone mineral density for each region of interest. Results: There was no association between age and volumetric bone mineral density in any region of interest (all R 2 ≤ 0.048, all p > 0.082). Patients who developed an acromial stress fracture were not significantly different from those who did not in terms of age, acromial volume, or acromial volumetric bone mineral density (all p > 0.559). Patients with known osteoporosis or osteopenia had slightly lower volumetric bone mineral density, but the differences were not significant (all p ≥ 0.072). Conclusion: Postoperative acromial fractures following reverse shoulder arthroplasty cannot be predicted by computed tomography-derived volumetric bone mineral density or volume. These mechanical characteristics also do not predictably decrease with age or osteoporosis diagnosis.

Increased stiffness and reoperation rate in partial rotator cuff repairs treated with a bovine patch: a propensity-matched trial.

BACKGROUND: Treating high-grade (grade 2 and 3) partial-thickness rotator cuff tears after failed conservative care remains challenging. Arthroscopic repair techniques are often considered with or without subacromial decompression and biological injections. More recently, a bioinductive bovine collagen patch (Regeneten; Smith & Nephew, Memphis, TN, USA) has been proposed to create a healing response and thicken the injured tendon. Although promising early results have been shown, previous studies lacked control subjects or comparison to other surgical treatments. The purpose of this study was to compare the reoperation rates of arthroscopic débridement and repair without a bioinductive collagen patch vs. arthroscopic débridement and repair with a bioinductive collagen patch in patients with high-grade partial-thickness rotator cuff tears in whom a minimum of 6 months of nonoperative treatment failed. METHODS: Thirty-two patients with high-grade partial-thickness supraspinatus tears were treated with surgical repair with a bioinductive patch. A control group of 32 patients with high-grade partial-thickness supraspinatus tears treated with débridement or tear completion and repair without a bioinductive patch was selected and matched for age, sex, and tear size. Patients were followed up at regular intervals of 6 weeks, 12 weeks, and 6 months postoperatively, and range of motion was assessed at respective clinic visits. Stiffness and reoperations were compared between groups. RESULTS: Postoperative stiffness was observed in the first 12 weeks in 8 of 32 patients in the patch group compared with 1 of 32 patients in the control group. Six patients in the patch group underwent reoperations compared with no patients in the control group (P < .001). All 6 reoperations in the patch group were performed to address stiffness. There were no differences in race, smoking status, or diabetes between groups (P > .05). CONCLUSION: Patients in the patch group had a significantly higher rate of postoperative stiffness. In the majority of patients in whom shoulder stiffness developed, reoperation was required.

The role of acromial morphometry in the development of acromial stress fracture following reverse total shoulder arthroplasty.

BACKGROUND: Indications for reverse total shoulder arthroplasty are expanding, and postoperative acromial stress fractures are a troubling postoperative complication. The purpose of this study was to determine if differences in acromial morphometry were present between cohorts with and without this complication. METHODS: A retrospective review of 101 reverse total shoulder arthroplasty procedures met criteria for the study. A total of eight acromial measurements on preoperative computed tomography scans were performed in axial, coronal, and sagittal views. Postoperative acromial stress fractures were confirmed by computed tomography scan on six patients and classified by fracture type. Statistical analysis was performed using a Mann-Whitney U test. RESULTS: The median acromial thickness at the posterior and lateral half was significantly thinner in the fracture cohort compared to the non-fracture cohort. Fracture and non-fracture cohort measurements demonstrated a median lateral thickness of 6.8 and 8.7 mm (p = 0.010), respectively, and median posterior thickness of 7.6 and 9.5 mm (p = 0.008), respectively. There were no demographic differences between cohorts. DISCUSSION: Two acromial measurements (lateral and posterior thickness) were associated with the development of postoperative acromial stress fracture following reverse total shoulder arthroplasty. These findings suggest that a thinner acromion in the lateral and posterior half is a risk factor for an acromial stress fracture following reverse total shoulder arthroplasty.

Union rate, complication rate, and opioid usage after Vancouver B periprosthetic femur fractures: a comparison of fracture types.

INTRODUCTION: Periprosthetic femur fractures are complex injuries that can be difficult to treat and recover from. With a growing number of total hip arthroplasties (THA) and revision arthroplasties being performed in an aging population, the incidence of these injuries is on the rise. Multiple studies exist detailing outcomes associated with periprosthetic femur fractures after THA, but no study has directly compared the post-operative course between fracture types as classified by the Vancouver classification system. This study compares the three Vancouver B fracture types to see if any type is associated with an increase in post-operative complications than others. MATERIALS AND METHODS: This retrospective chart review was conducted at a suburban orthopedic surgery department. Overall, 122 patients who presented to our hospital with periprosthetic proximal femur fractures after hip arthroplasty over the past 13 years were reviewed. Patients were included if they underwent surgical stabilization of their femur fracture. Patients were excluded if they underwent non-operative treatment or had missing chart information. For each patient, demographic information, fracture information, surgical information, post-operative course, and post-operative opioid usage were recorded and compared among groups. RESULTS: Overall, 88 fractures were included. Fifty-five (62.5%) were Vancouver type B1, 27 (30.7%) were Vancouver type B2, and 6 (6.8%) were Vancouver type B3. Most of our patients were female (n = 62, 70.5%) and older than 81 years of age (n = 53, 60.2%) with uncemented prosthesis (n = 83, 94.3%). All three fracture groups had statistically similar union rates (p = 0.77), infection rates (p = 0.32), subsequent fractures (p = 0.63), repeat surgeries (p = 0.64), and post-operative opioid use (measured in milli-morphine equivalents) after surgical stabilization (p = 0.96). CONCLUSIONS: While periprosthetic femur fractures after hip arthroplasty are associated with high complication rates and poor outcomes, there is no difference in union rate, infection rate, subsequent fractures, repeat surgery rate, and opioid usage between the different Vancouver B fracture types. LEVEL OF EVIDENCE: Prognostic level III.

Risk factors for complications and return to the emergency department after interscalene block using liposomal bupivacaine for shoulder surgery.

BACKGROUND: Exparel (liposomal bupivacaine) has recently gained favor for use in interscalene regional blocks for shoulder surgery. While effective for pain relief, this does have adverse effects that can lead to postoperative emergency department (ED) visits. This study aimed to identify any patient risk factors that are associated with complications leading to ED return visits owing to interscalene blocks using Exparel before shoulder surgery. METHODS: A retrospective chart review was performed for all patients undergoing shoulder surgery with an Exparel interscalene block in an 8-month period. For each patient, demographic information, comorbidities, type of block, postoperative complications, ED return visits, and readmissions were recorded. The 5-factor modified Frailty Index score and the Charlson Comorbidity Index score were calculated. Univariate and multivariate logistic regressions were conducted to identify risk factors associated with increased complications and return to the ED. RESULTS: Overall, 352 patients were included; most patients were men, were aged between 51 and 70 years, and had a body mass index of 25.0-35.0. Postoperative complications related to the Exparel interscalene block occurred in 58 patients (16.5%), including 37 minor complications (10.5%) and 21 major complications (6.0%) that led to return ED visits. Univariate analysis yielded American Society of Anesthesiologists (ASA) score (P = .03) as a significant predictor of minor complications. Multivariate logistic regression analysis yielded ASA score (P = .096; odds ratio, 1.64) as trending toward being a significant risk factor for minor complications. Univariate analysis yielded age (P = .006), ASA score (P = .009), and Charlson Comorbidity Index score (P = .002) as significant predictors of major complications. Multivariate logistic regression analysis yielded ASA score (P = .049; odds ratio, 2.25) as the only significant risk factor for major complications. CONCLUSION: Surgeons and anesthesiologists should strongly consider a patient's ASA score, in addition to his or her pulmonary and cardiac history, when deciding whether the patient is an appropriate candidate for an interscalene regional block using Exparel for shoulder surgery.

Surgical fixation of pilon injuries: a comparison of the anterolateral and posterolateral approach.

PURPOSE: This study looks to compare patient outcomes in those with pilon fractures fixed with the anterolateral approach versus those with the posterolateral approach. METHODS: 135 patient charts of those with surgically treated pilon fractures over a 7-year period were retrospectively reviewed, recording demographic information, fracture description, surgical intervention timeline, operative outcomes, patient outcomes, and complication rates. RESULTS: Of the 44 included patients (32 anterolateral and 12 posterolateral), most were older than 40 years of age (65.9%) and male (63.6%). There was no difference seen between anterolateral approach and posterolateral approach tourniquet times (p = 0.80), operating room time (p = 0.40), or estimated blood loss (p = 0.73). There was also no reported difference in decrease in Numerical Rating Scale pain scores (p = 0.38), FOTO (Focus on Therapeutic Outcomes) percent increase (p = 0.13), active flexion-extension axis range of motion (p = 0.35), or inversion-eversion axis (p = 0.25) range of motion after an anterolateral approach versus a posterolateral approach. Finally, statistically similar complication rates (p = 0.75) were seen between anterolateral and posterolateral approaches, but patients who underwent a posterolateral approach surgical fixation were trending towards significantly using more post-operative outpatient opioid medications for pain control compared to those who underwent surgical fixation with an anterolateral approach (p = 0.09). CONCLUSIONS: Pilon injuries that lend themselves to anterolateral fixation have similar outcomes peri-operatively and post-operatively compared to injuries lending to posterolateral fixation. Both approaches can be used as dictated by the injury not fearing poorer outcomes or increased complication rates. However, surgeons must be wary of high complication rates associated with all pilon injury patterns. LEVEL OF EVIDENCE: Therapeutic Level IV.

An evaluation of prophylactic treatments to prevent post traumatic joint stiffness.

Arthrofibrosis is a major obstacle to restoring joint function after trauma. The objective of this study was to evaluate montelukast, forskolin, and triamcinolone as possible means of prophylaxis against the formation of arthrofibrosis. Forty-eight rats underwent surgical knee trauma with post-operative immobilization in full flexion. The treatment groups were: control (CTL), oral montelukast (3.75 mg/kg/day) (MLK), intra-articular forskolin injections (0.6 mg/kg) (FSK), and intra-articular triamcinolone injections (0.68 mg/kg) (STR). Rats were sacrificed after 14 days and femorotibial contracture angles were measured with the posterior capsule intact and with the posterior capsule cut. A 0.015Nm extension moment was applied to the knee. All treatment groups had significant reductions in contracture angle compared to the control. Mean contractures with the posterior capsule intact were 32°(CTL), 20° (MLK), 22° (FSK), and 7° (STR). Contractures with the posterior capsule cut were 28° (CTL), 19° (MLK), 20° (FSK), and 5° (STR). The STR group was significantly better than FSK and MLK. Triamcinolone injections provided dramatic reductions in stiffness. Both forskolin and montelukast provided significant, though lesser, reductions in stiffness. While the triamcinolone contracture angles were significantly better, the novel treatments of forskolin and montelukast provided encouraging results and should be studied further.

Sequential Pd(0)-, Rh(I)-, and Ru(II)-catalyzed reactions in a nine-step synthesis of clinprost.

A step-economical synthesis of clinprost is reported that concludes with 3 different transition metal-catalyzed reactions: Pd-catalyzed decarboxylation with allylic rearrangement, Rh-catalyzed diene-ene [2+2+1] reaction, and Ru-catalyzed cross-metathesis reaction. The complexity bestowed to the molecule from these reactions converts a readily accessible ester to clinprost without using protecting groups in only 9 total steps.