Efficacy of ADIPOR1 and ADIPOR2 peptide-agonist AdipoRon in preventing contracture in a rabbit model of arthrofibrosis

AdipoRon is an adiponectin receptor 1, 2 (ADIPOR1 and ADIPOR2) agonist with potential antifibrotic effects. Whether AdipoRon can mitigate joint stiffness in a rabbit model of arthrofibrosis is unknown. We examined the efficacy of intravenous (IV) AdipoRon at mitigating contracture in a rabbit model of knee arthrofibrosis. Fifty-six female New Zealand White rabbits were divided into three dosing groups: vehicle (dimethyl sulfoxide, DMSO), 2.5 mg/kg AdipoRon, and 5 mg/kg AdipoRon. AdipoRon, in DMSO, was administered IV preoperatively and for 5 days postoperatively (30 rabbits, Aim 1). AdipoRon was again dosed similarly after Kirschner wire (K-wire) removal at 8 weeks (26 rabbits; Aim 2). The primary outcome of joint passive extension angle (PEA,°) was measured at 8, 10, 12, 16, and 24 weeks following index surgery. At 24 weeks, rabbits were euthanized and limbs were harvested to measure posterior capsular stiffness (N cm/°). In Aim 1, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 16-week (p < 0.05). In Aim 2, the 5 mg/kg treated rabbits had a significant increase in PEA when compared to controls at 10-week (p < 0.05). In both aims, no significant differences were observed at later time points. Capsular stiffness was no different in any group. We are the first to report the efficacy of IV AdipoRon in a rabbit model of arthrofibrosis. We identified a significant dose-dependent decrease in joint PEA at early time points; however, no differences were observed between groups at later time points. Clinical Significance: The present investigation provided the first assessment of AdipoRon's efficacy in mitigating knee stiffness in the current gold standard rabbit model of arthrofibrosis. Results of this investigation provided further evidence as to the potential role of AdipoRon as a preventative for arthrofibrosis in large mammals.

Complications of Antibiotic Cement Spacers Used for Elbow Infections

INTRODUCTION

Antibiotic cement spacers have been widely used in the treatment of joint infections. There are no commercially available antibiotic spacers for the elbow. Instead, they are typically fashioned by the surgeon at the time of surgery using cement alone or a combination of cement with sutures, Steinmann pins, external fixator components, or elbow arthroplasty components. There is no consensus regarding the ideal elbow antibiotic spacer and no previous studies have examined the complications associated with these handmade implants in relation to their unique structural design.

METHODS

We retrospectively reviewed 55 patients who had 78 static antibiotic cement spacers implanted between January 1998 and February 2021 as part of a 2-stage treatment plan for infection of an elbow arthroplasty, other elbow surgery, or primary elbow infection. Several antibiotic spacer structures were used during the study period. For analysis purposes, the spacers were classified into linked and unlinked spacers based on whether there was a linking mechanism between the humerus and the ulna. Complications related to these spacers that occurred either during the implantation, between implantation and removal, or during removal were recorded and analyzed from chart review and follow-up x rays. Re-operations due to spacer-related complications were also recorded.

RESULTS

Among the 55 patients (78 spacers), there were 23 complications, including 17 minor and 6 major complications. The most common complication of unlinked spacers (intramedullary (IM) dowels, beads and cap spacer) was spacer displacement. Other complications included IM dowel fracture and difficulty locating beads during spacer removal. The major complications of linked cement spacers included two periprosthetic humerus fractures after internal external fixator cement spacers and re-operation due to breakage and displacement of one bushing cement spacer. The major complications of unlinked cement spacers included two reoperations due to IM dowel displacement and one reoperation due to displacement of beads. Among patients who had removal of all components and those with native joints, there was no statistically significant difference between internal external fixator cement spacers and unlinked cement spacers in minor complication rates (30% versus 16%, p=0.16), major complication rates (7% versus 8%, p=0.85) and re-operation rates (0% versus 8%, p=0.12).

CONCLUSIONS

Static handmade antibiotic elbow spacers have unique complications related to their structural designs. The most common complication of linked and non-linked cement spacers were failure of the linking mechanism and displacement, respectively. Surgeons should keep in mind the possible complications of different structures of cement spacers when choosing one antibiotic spacer structure over another.

Mid- to long-term outcomes of latissimus dorsi tendon transfer for massive irreparable posterosuperior rotator cuff tears: a systematic review and meta-analysis

BACKGROUND

This study aims to analyze the mid-to long-term results of the latissimus dorsi tendon for the treatment of massive posterosuperior irreparable rotator cuff tears as reported in high-quality publications and to determine its efficacy and safety.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. PubMed, Scopus, and EMBASE databases were searched until December 2022 to identify studies with a minimum 4 year follow-up. Clinical and radiographic outcomes, complications, and revision surgery data were collected. The publications included were analyzed quantitatively using the DerSimonian Laird random-effects model to estimate the change in outcomes from the preoperative to the postoperative condition. The proportion of complications and revisions were pooled using the Freeman-Tukey double arcsine transformation.

RESULTS

Of the 618 publications identified through database search, 11 articles were considered eligible. A total of 421 patients (432 shoulders) were included in this analysis. Their mean age was 59.5 ± 4 years. Of these, 277 patients had mid-term follow-up (4-9 years), and 144 had long-term follow-up (more than 9 years). Postoperative improvements were considered significant for the following outcome parameters: Constant-Murley Score (0-100 scale), with a mean difference (MD) = 28 points (95% confidence interval [CI] 21, 36; I2 = 89%; P < .001); visual analog scale, with a standardized MD = 2.5 (95% CI 1.7, 3.3; P < .001; I2 = 89%; P < .001); forward flexion, with a MD = 43° (95% CI 21°, 65°; I2 = 95% P < .001); abduction, with a MD = 38° (95% CI 20°, 56°; I2 = 85%; P < .01), and external rotation, with a MD = 8° (95% CI 1°, 16°; I2 = 87%; P = .005). The overall reported mean complication rate was 13% (95% CI 9%, 19%; I2 = 0%), while the reported mean revision rate was 6% (95% CI: 3%, 9%; I2 = 0%).

CONCLUSIONS

Our pooled estimated results seem to indicate that latissimus dorsi tendon transfer significantly improves patient-reported outcomes, pain relief, range of motion, and strength, with modest rates of complications and revision surgery at mid-to long-term follow-up. In well-selected patients, latissimus dorsi tendon transfer may provide favorable outcomes for irreparable posterosuperior cuff tears.

Trans-ulnar fracture dislocations of the elbow: a systematic review and clarification of classification systems

BACKGROUND

Complex elbow dislocations in which the dorsal cortex of the ulna is fractured can be difficult to classify and therefore treat. These have variably been described as either Monteggia variant injuries or trans-olecranon fracture dislocations. Additionally, O'Driscoll et al classified coronoid fractures that exit the dorsal cortex of the ulna as "basal coronoid, subtype 2" fractures. The Mayo classification of trans-ulnar fracture dislocations categorizes these injuries in 3 types according to what the coronoid remains attached to: trans-olecranon fracture dislocations, Monteggia variant fracture dislocations, and trans-ulnar basal coronoid fracture dislocations. The purpose of this study was to evaluate the outcomes of these injury patterns as reported in the literature. Our hypothesis was that trans-ulnar basal coronoid fracture dislocations would have a worse prognosis.

MATERIALS AND METHODS

We conducted a systematic review to identify studies with trans-ulnar fracture dislocations that had documentation of associated coronoid injuries. A literature search identified 16 qualifying studies with 296 fractures. Elbows presenting with basal subtype 2 or Regan/Morrey III coronoid fractures and Jupiter IIA and IID injuries were classified as trans-ulnar basal coronoid fractures. Patients with trans-olecranon or Monteggia fractures were classified as such if the coronoid was not fractured or an associated coronoid fracture had been classified as O'Driscoll tip, anteromedial facet, basal subtype I, or Regan Morrey I/II.

RESULTS

The 296 fractures reviewed were classified as trans-olecranon in 44 elbows, Monteggia variant in 82 elbows, and trans-ulnar basal coronoid fracture dislocations in 170 elbows. Higher rates of complications and reoperations were reported for trans-ulnar basal coronoid injuries (40%, 25%) compared to trans-olecranon (11%, 18%) and Monteggia variant injuries (25%, 13%). The mean flexion-extension arc for basal coronoid fractures was 106° compared to 117° for Monteggia (P < .01) and 121° for trans-olecranon injuries (P = .02). The mean Mayo Elbow Performance Score was 84 points for trans-ulnar basal coronoid, 91 for Monteggia (P < .01), and 93 for trans-olecranon fracture dislocations (P < .05). Disabilities of the Arm, Shoulder and Hand and American Shoulder and Elbow Surgeons scores were 22 and 80 for trans-ulnar basal coronoid, respectively, compared to 23 and 89 for trans-olecranon fractures. American Shoulder and Elbow Surgeons was not available for any Monteggia injuries, but the mean Disabilities of the Arm, Shoulder and Hand was 13.

DISCUSSION

Trans-ulnar basal coronoid fracture dislocations are associated with inferior patient reported outcome measures, decreased range of motion, and increased complication rates compared to trans-olecranon or Monteggia variant fracture dislocations. Further research is needed to determine the most appropriate treatment for this difficult injury pattern.

Lower Trapezius Transfer Improves Clinical Outcomes With a Rate of Complications and Reoperations Comparable to Other Surgical Alternatives in Patients with Functionally Irreparable Rotator Cuff Tears: A Systematic Review

PURPOSE

To analyze the clinical outcomes of lower trapezius transfer (LTT) for patients with functionally irreparable rotator cuff tears (FIRCT) and summarize the available literature regarding complications and reoperations.

METHODS

After registration in the International prospective register of systematic reviews (PROSPERO [CRD42022359277]), a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines was performed. Inclusion criteria were English, full-length, peer-reviewed publications with a level of evidence IV or higher reporting on clinical outcomes of LTT for FIRCT. Ovid MEDLINE, Embase, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus via Elsevier databases were searched. Clinical data, complications and revisions were systematically recorded.

RESULTS

Seven studies with 159 patients were identified. The mean age range was 52 to 63 years, 70.4% of the patients included were male, and the mean follow-up time ranged between 14 and 47 months. At final follow-up, LTT lead to improvements in range of motion, with reported forward elevation (FE) and external rotation (ER) mean gains of 10° to 66° and 11° to 63°, respectively. ER lag was present before surgery in 78 patients and was reversed after LTT in all shoulders. Patient-reported outcomes were improved at final follow-up, including the American Shoulder and Elbow Society score, Shoulder Subjective Value and Visual Analogue Scale. The overall complication rate was 17.6%, and the most reported complication was posterior harvest site seroma/hematoma (6.3%). The most common reoperation was conversion to reverse shoulder arthroplasty (5%) with an overall reoperation rate of 7.5%.

CONCLUSIONS

Lower trapezius transfer improves clinical outcomes in patients with irreparable rotator cuff tears with a rate of complications and reoperations comparable to other surgical alternatives in this group of patients. Increases in forward flexion and ER are to be expected, as well as a reversal of ER lag sign when present before surgery.

LEVEL OF EVIDENCE

Level IV, systematic review of Level III-IV studies.

Proximal Humerus Reconstruction for Bone Sarcomas: A Critical Analysis

» The proximal humerus is a common location for primary bone tumors, and the goal of surgical care is to obtain a negative margin resection and subsequent reconstruction of the proximal humerus to allow for shoulder function.» The current evidence supports the use of reverse total shoulder arthroplasty over hemiarthroplasty when reconstructing the proximal humerus after resection of a bone sarcoma if the axillary nerve can be preserved.» There is a lack of high-quality data comparing allograft prosthetic composite (APC) with endoprosthetic reconstruction of the proximal humerus.» Reverse APC should be performed using an allograft with donor rotator cuff to allow for soft-tissue repair of the donor and host rotator cuff, leading to improvements in shoulder motion compared with an endoprosthesis.

Reverse shoulder arthroplasty megaprosthesis for surgical management of severe proximal humeral bone loss

BACKGROUND

Shoulder arthroplasty in the setting of severe proximal humerus bone loss can be challenging. The purpose of this study was to evaluate the outcomes of a modular segmental megaprosthesis when implanted in a reverse configuration for complex primary arthroplasty, reconstruction at the time of oncologic resection, and revision shoulder arthroplasty.

MATERIALS AND METHODS

A Joint Registry Database was queried to identify all shoulder arthroplasties performed at a single institution using the Comprehensive Segmental Revision System reverse shoulder arthroplasty (SRS-RSA; Zimmer Biomet). A retrospective review of electronic medical records and radiographs was performed to record demographic data, indication, outcomes, complications, and revision surgery.

RESULTS

Between February 2012 and October 2022, a total of 76 consecutive SRS-RSAs were implanted. An analysis of patients with minimum 12-month follow-up yielded 53 patients with a mean follow-up of 4.1 ± 2.43 years. Surgical complication rate in this cohort was observed in 41.5% (22 of 53) of cases. Overall, the revision rate at final follow-up was 26.4% (14 of 53), with a significant difference between the primary and revision cohorts. The number of prior surgeries was a significant risk factor for revision surgery, with a hazard ratio of 1.789 (95% confidence interval 1.314-2.436, P < .001). When analyzing aseptic humeral loosening rates across study cohorts, a significant difference was found between the primary arthroplasty (0%, n = 0) and the revision arthroplasty cohorts (22.2%, n = 6) (P = .04).

DISCUSSION

Reverse shoulder arthroplasty using a modular segmental megaprosthesis remains a reasonable salvage option for shoulder reconstruction in the setting of proximal humeral bone loss. Because of the substantial bone loss and soft tissue deficiencies typically present in these cases, surgeons should educate patients on the relatively high complication rate, particularly when used in the setting of a previous failed arthroplasty.

AdipoRon reduces TGFβ1-mediated collagen deposition in vitro and alleviates knee stiffness in vivo

Arthrofibrosis, which causes joint motion restrictions, is a common complication following total knee arthroplasty (TKA). Key features associated with arthrofibrosis include myofibroblast activation, knee stiffness, and excessive scar tissue formation. We previously demonstrated that adiponectin levels are suppressed within the knee tissues of patients affected by arthrofibrosis and showed that AdipoRon, an adiponectin receptor agonist, exhibited anti-fibrotic properties in human mesenchymal stem cells. In this study, the therapeutic potential of AdipoRon was evaluated on TGFβ1-mediated myofibroblast differentiation of primary human knee fibroblasts and in a mouse model of knee stiffness. Picrosirius red staining revealed that AdipoRon reduced TGFβ1-induced collagen deposition in primary knee fibroblasts derived from patients undergoing primary TKA and revision TKA for arthrofibrosis. AdipoRon also reduced mRNA and protein levels of ACTA2, a key myofibroblast marker. RNA-seq analysis corroborated the anti-myofibrogenic effects of AdipoRon. In our knee stiffness mouse model, 6 weeks of knee immobilization, to induce a knee contracture, in conjunction with daily vehicle (DMSO) or AdipoRon (1, 5, and 25 mg/kg) via intraperitoneal injections were well tolerated based on animal behavior and weight measurements. Biomechanical testing demonstrated that passive extension angles (PEAs) of experimental knees were similar between vehicle and AdipoRon treatment groups in mice evaluated immediately following immobilization. Interestingly, relative to vehicle-treated mice, 5 mg/kg AdipoRon therapy improved the PEA of the experimental knees in mice that underwent 4 weeks of knee remobilization following the immobilization and therapy. Together, these studies revealed that AdipoRon may be an effective therapeutic modality for arthrofibrosis.

Open and Arthroscopic Elbow Contracture Release: Tips and Pearls

Elbow stiffness is a common consequence of trauma and can significantly limit the functionality of the affected arm. Intervention may be necessary for those with a motion arc less than 100°, but the decision to intervene should be based on individual patient needs. Restoration of joint motion in a stiff elbow can be challenging, time consuming, and costly. Nonsurgical treatment is the primary management option, and surgical intervention is considered for refractory stiffness. However, recurrent stiffness is a common issue following surgical elbow contracture release. An overview of relevant elbow anatomy, principles and technical pearls of arthroscopic and open contracture release, and postoperative rehabilitation methods to reduce the risk of recurrent stiffness is provided. It is important to tailor the treatment plan to each patient's unique needs and functional expectations.

A coronoid-centric classification system of proximal trans-ulnar fracture-dislocations has almost perfect intraobserver and interobserver agreement

BACKGROUND

Fracture-dislocations of the elbow, particularly those that involve a fracture through the proximal ulna, are complex and can be difficult to manage. Moreover, current classification systems often cannot discriminate between Monteggia-variant injury patterns and trans-olecranon fracture-dislocations, particularly when the fracture involves the coronoid. The Mayo classification of proximal trans-ulnar fracture-dislocations categorizes these fractures into 3 types according to what the coronoid is still attached to: trans-olecranon fracture-dislocations (the coronoid is still attached to the ulnar metaphysis); Monteggia-variant fracture-dislocations (the coronoid is still attached to the olecranon); and ulnar basal coronoid fracture-dislocations (the coronoid is not attached to either the olecranon or the ulnar metaphysis). The purpose of this study was to evaluate the intraobserver and interobserver agreement of the Mayo classification system when assessing elbow fracture-dislocations involving the proximal ulna based on radiographs and computed tomography scans.

METHODS

Three fellowship-trained shoulder and elbow surgeons and 2 fellowship-trained orthopedic trauma surgeons blindly and independently evaluated the radiographs and computed tomography scans of 90 consecutive proximal trans-ulnar fracture-dislocations treated at a level I trauma center. The inclusion criteria included subluxation or dislocation of the elbow and/or radioulnar joint with a complete fracture through the proximal ulna. Each surgeon classified all fractures according to the Mayo classification, which is based on what the coronoid remains attached to (ulnar metaphysis, olecranon, or neither). Intraobserver reliability was determined by scrambling the order of the fractures and having each observer classify all the fractures again after a washout period ≥ 6 weeks. Interobserver reliability was obtained to assess the overall agreement between observers. κ Values were calculated for both intraobserver reliability and interobserver reliability.

RESULTS

The average intraobserver agreement was 0.87 (almost perfect agreement; range, 0.76-0.91). Interobserver agreement was 0.80 (substantial agreement; range, 0.70-0.90) for the first reading session and 0.89 (almost perfect agreement; range, 0.85-0.93) for the second reading session. The overall average interobserver agreement was 0.85 (almost perfect agreement; range, 0.79-0.91).

CONCLUSION

Classifying proximal trans-ulnar fracture-dislocations based on what the coronoid remains attached to (olecranon, ulnar metaphysis, or neither) was associated with almost perfect intraobserver and interobserver agreement, regardless of trauma vs. shoulder and elbow fellowship training. Further research is needed to determine whether the use of this classification system leads to the application of principles specific to the management of these injuries and translates into better outcomes.

Increasing severity of preoperative anemia is associated with higher postoperative medical and surgical complications after primary shoulder arthroplasty

BACKGROUND

Anemia is a major cause of morbidity worldwide and compounds numerous medical conditions. Studies have found associations between anemia and both medical and surgical complications after shoulder arthroplasty (SA); however, most of these studies have used commercially available national databases with limited information on outcomes and typically short-term follow-up. Our study sought to evaluate the midterm outcomes of primary SA at a single institution when stratified by the degree of preoperative anemia.

METHODS

Between 2000 and 2020, 5231 primary SA (477 hemiarthroplasties, 2091 anatomic total SA, and 2335 reverse SA) with preoperative hematocrit values available and a minimum follow-up of 2 years were collected from a single-institution joint registry database. The severity of anemia was subclassified as no anemia (hematocrit >39% for males, >36% for females; n = 4194 [80.2%]), mild anemia (hematocrit 33%-39% for males, 33%-36% for females; n = 742 [14.2%]), and moderate-to-severe anemia (hematocrit <33% for both males and females; n = 295 [5.6%]). The mean follow-up time for the entire cohort was 5.9 years (range, 2-22 years). Medical and surgical complications, reoperations, revisions, and implant survivorship were assessed.

RESULTS

SA with moderate-to-severe anemia had the highest rate of nonfatal and nontransfusion medical complications (5.1%) relative to the nonanemic (1.2%; P < .001) and mild anemic groups (1.5%; P < .001). Similarly, SA with moderate-to-severe anemia had the highest rate of surgical complications (19.3%) compared with mild anemia (14.3%; P = .044) and no anemia (11.6%; P < .001). Postoperative transfusion was most frequent in the moderate-to-severe anemia cohort (40.3%) compared with the mild anemia (14.2%; P < .001) and nonanemic groups (2.5%; P < .001). Furthermore, SA who received postoperative transfusions had a higher risk of nonfatal medical complications (8.2% vs. 1.0%; P < .001), 90-day mortality (1.5% vs. 0.03%; P = .001), and surgical complications (19.5% vs. 12.0%; P < .001) when compared with those without transfusion.

CONCLUSIONS

Moderate-to-severe anemia (hematocrit <33% for both males and females) was identified in approximately 5.6% of patients who underwent SA at a single institution and was associated with increased medical and surgical complications. Patients who received postoperative transfusions presented elevated rates of medical complications, 90-day mortality, and surgical complications. Health care teams should be aware of these risks in order to provide more individualized medical optimization and postoperative monitoring.

Outcomes of Humeral Allograft-Prosthetic Composites with Plate Fixation in Revision Total Elbow Arthroplasty

Background

Traditionally, the reconstruction of severe distal humeral bone loss at the time of revision total elbow arthroplasty (TEA) has used allograft-prosthetic composites (APCs) stabilized with cerclage wires or cables. We have migrated to plate fixation when revision TEA using a humeral APC is performed. This study shows the outcomes of patients treated with a humeral APC with plate fixation during revision TEA.

Methods

Between 2009 and 2019, 41 humeral APCs with plate fixation of distal humeral allograft to the native humerus were performed in the setting of revision TEA. There were 12 male patients (29%) and 29 female patients (71%), with a mean age of 63 years (range, 41 to 87 years). The mean allograft length was 12 cm. All elbows had a minimum follow-up of 2 years (mean follow-up, 3.3 years). Patients were evaluated for visual analog scale pain scores, range of motion, the ability to perform select activities of daily living, and the Mayo Elbow Performance Score (MEPS). Outcomes including reoperations, complications, and revisions were noted. The most recent radiographs were evaluated for union at the allograft-host interface, failure of the plate-and-screw construct, or component loosening.

Results

The mean postoperative flexion was 124° (range, 60° to 150°) and the mean postoperative extension was 26° (range, 0° to 90°); the mean arc of motion was 99° (range, 30° to 150°). The mean MEPS was 58 points (range, 10 to 100 points). Two surgical procedures were complicated by neurologic deficits. The overall reoperation rate was 14 (34%) of 41. Of the 33 patients with complete radiographic follow-up, 12 (36%) had evidence of nonunion at the allograft-host interface with humeral component loosening, 1 (3%) had evidence of partial union, and 1 (3%) had ulnar stem loosening.

Conclusions

Revision TEA with a humeral APC using compression plating was successful in approximately two-thirds of the elbows. Further refinement of surgical techniques is needed to improve union rates in these complex cases.

Level of Evidence

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Improved Yet Varied Clinical Outcomes Observed With Comparison of Arthroscopic Superior Capsular Reconstruction Versus Arthroscopy-Assisted Lower Trapezius Transfer for Patients With Irreparable Rotator Cuff Tears

PURPOSE

To evaluate the outcomes of arthroscopic superior capsular reconstruction (SCR) and arthroscopy-assisted lower trapezius tendon transfer (LTT) for posterosuperior irreparable rotator cuff tears (IRCTs).

METHODS

Over an almost 6-year period (October 2015 to March 2021), all patients who underwent IRCT surgery with a minimum 12-month follow-up period were identified. For patients with a substantial active external rotation (ER) deficit or lag sign, LTT was preferentially selected. Patient-reported outcome scores included the visual analog scale (VAS) pain score, strength score, American Shoulder and Elbow Surgeons Standardized Shoulder Assessment Form (ASES) score, Single Assessment Numeric Evaluation (SANE) score, and Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) score.

RESULTS

We included 32 SCR patients and 72 LTT patients. Preoperatively, LTT patients had more advanced teres minor fatty infiltration (0.3 vs 1.1, P = .009), a higher global fatty infiltration index (1.5 vs 1.9, P = .035), and a higher presence of the ER lag sign (15.6% vs 48.6%, P < .001). At a mean follow-up of 2.9 ± 1.3 years (range, 1.0-6.3 years), no differences in patient-reported outcome scores were observed. Postoperatively, SCR patients had a lower VAS score (0.3 vs 1.1, P = .017), higher forward elevation (FE) (156° vs 143°, P = .004), and higher FE strength (4.8 vs 4.5, P = .005) and showed greater improvements in the VAS score (6.8 vs 5.1, P = .009), FE (56° vs 31°, P = .004), and FE strength (1.0 vs 0.4, P < .001). LTT patients showed greater improvement in ER (17° vs 29°, P = .026). There was no statistically significant between-cohort difference in complication rate (9.4% vs 12.5%, P = .645) or reoperation rate (3.1% vs 10%, P = .231).

CONCLUSIONS

With adequate selection criteria, both SCR and LTT provided improved clinical outcomes for posterosuperior IRCTs. Additionally, SCR led to better pain relief and restoration of FE whereas LTT provided more reliable improvement in ER.

LEVEL OF EVIDENCE

Level III, treatment study with retrospective cohort comparison.

The Value of Computer-Assisted Navigation for Glenoid Baseplate Implantation in Reverse Shoulder Arthroplasty: A Systematic Review and Meta-Analysis

BACKGROUND

Glenoid baseplate malpositioning during reverse total shoulder arthroplasty can contribute to perimeter impingement, dislocation, and loosening. Despite advances in preoperative planning, conventional instrumentation may lead to considerable inaccuracy in implant positioning unless patient-specific guides are used. Optical navigation has the potential to improve accuracy and precision when implanting a reverse shoulder arthroplasty baseplate. This systematic review aimed to analyze the most recent evidence on the accuracy and precision of glenoid baseplate positioning using intraoperative navigation and its potential impact on component selection and surgical time.

METHODS

We conducted a systematic review following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. The PubMed, Scopus, and EMBASE databases were queried in July 2022 to identify all studies that compared navigation vs. conventional instrumentation for reverse shoulder arthroplasty. Data of deviation from the planned baseplate version and inclination, the use of standard or augmented glenoid components, and surgical time were extracted. Quantitative analysis from the included publications was performed using the inverse-variance approach and Mantel-Haenszel method.

RESULTS

Of the 2,048 records identified in the initial query, only 10 articles met the inclusion and exclusion criteria, comprising 667 shoulders that underwent reverse total shoulder arthroplasty. The pooled mean difference (MD) of the deviation from the planned baseplate position for the clinical studies was -0.44 (95% confidence interval [CI], -3.26; p = 0.76; I2 = 36%) for version and -8.75 (95% CI, -16.83 to -0.68; p = 0.02; I2 = 83%) for inclination, both in favor of navigation. The odds ratio of selecting an augmented glenoid component after preoperative planning and navigation-assisted surgery was 8.09 (95% CI, 3.82-17.14; p < 0.00001; I2 = 60%). The average surgical time was 12 minutes longer in the navigation group (MD 12.46, 95% CI, 5.20-19.72; p = 0.0008; I2 = 71%).

CONCLUSIONS

Preoperative planning integrated with computer-assisted navigation surgery seems to increase the accuracy and precision of glenoid baseplate inclination compared with the preoperatively planned placement during reverse total shoulder arthroplasty. The surgical time and proportion of augmented glenoid components significantly increase when using navigation. However, the clinical impact of these findings on improving prosthesis longevity, complications, and patient functional outcomes is still unknown.

LEVEL OF EVIDENCE

Level III, systematic review and meta-analysis. See Instructions for Authors for a complete description of levels of evidence.

Intraoperative modification of total elbow arthroplasty implants

BACKGROUND

Modification of total elbow arthroplasty (TEA) implants may be necessary in selected patients with substantial anatomic bone deformity or those undergoing revision surgery. The purpose of this study was to investigate the prevalence and consequences of implant modifications during TEA at our institution. We hypothesized that TEA implant modification would be more common in revisions than in primary replacements, and that it would not be associated with worse clinical outcomes or increased rates of radiographic or surgical complications directly related to the implant modification.

METHODS

Elbows that had undergone TEA by any of 3 surgeons at our institution with use of intraoperative implant modification between January 1992 and October 2019 were retrospectively reviewed for the type of modification and complications. Complications were classified as definitely related, probably related, possibly related, or nonrelated to the implant's modification according to the consensus review by the 3 senior surgeons. A survey was sent out to surgeons outside of our institution to investigate whether intraoperative modification to TEA implants is a common clinical practice.

RESULTS

A total of 106 implant components were modified during 94 of 731 TEA procedures (13%) in 84 of 560 patients. Implant modifications were performed in 60 of 285 revision cases (21%) compared with 34 of 446 (8%) primary cases (P < .0001). These included shortening the stem in 40 (44%), bending the stem in 16 (15%), notching the stem in 16 (15%), tapering the stem in 9 (9%), and a combination of 2 or more of these modifications in 19 implants (17%). Among the 55 index surgeries available for complication analysis, 40 complications occurred in 28 index surgeries (11 primary and 17 revisions; 25 patients), making the overall complication rate 51%. Of these 40 complications, 23 were considered independent of any implant modification. Of the remaining 17 complications, 9 were considered nonrelated to the implant modification, 6 were possibly related, and 2 were probably related to the implant modification. Therefore, the complication rate possibly related or probably related to implant modification was 15% (8 of 55). No complication was classified as definitely related to the implant modification. No implant breakage or malfunction occurred after any modification. A total of 442 survey responses were received representing 29 countries, of which 144 surgeons (39%) performed modification to implants during TEA procedures.

DISCUSSION

This study confirmed our hypothesis that modification of TEA implants is not uncommon at our institution, particularly in revision arthroplasty. Surgeons should keep in mind that complications possibly related or probably related to implant modification were at minimum 15% and could have been as high as 30% if the patients lost to follow-up had all had complications. Implant modification may be necessary in some cases but should be exercised with thoughtful consideration and caution.

Extended deltopectoral approach for revision total elbow arthroplasty requiring humeral allograft-prosthetic composites in patients with severely compromised proximal humerus bone stock

Background

Severe humeral bone loss in the setting of failed total elbow arthroplasty (TEA) poses a particularly challenging reconstructive problem. The objective of this study was to review the rationale, indications, contraindications, and detailed surgical technique for using an extended anterior deltopectoral approach to perform a revision TEA when substantially long allografts are required in the presence of severely compromised proximal humerus bone stock.

Methods

The authors developed this exposure and reconstructive strategy for failed elbow arthroplasties where the remaining segment of proximal humerus is extremely short, which makes adequate plate fixation of an allograft-prosthetic composite (APC) to the native bone extremely challenging. From an anterior deltopectoral approach, it is possible to use dedicated long, precontoured proximal humerus locking plates to maximize fixation in any remaining proximal humerus. This exposure still makes it possible to provide adequate access to the coupling mechanism of the humeral and ulnar components for implantation of a linked elbow arthroplasty. This exposure also allows for adequate judgment of humeral length and rotation.

Pitfalls and Challenges

Crucial steps in the surgery include extending the dissection past the elbow flexion crease such that one can obtain circumferential exposure of the distal humerus. It is also important to couple the humeral and ulnar components prior to committing to the length of the APC. Special attention must be paid to gauge appropriate APC rotation and length for proper soft tissue tension. When performing fixation of the proximal humeral plate, screw purchase must be maximized in both the remaining native proximal humerus and the APC. Compression across the allograft-host interface is paramount for healing to occur.

Conclusion

An extended anterior deltopectoral approach to perform a revision TEA when very long APCs are required is a viable option to restore humeral bone stock and regain humeral stem fixation in the setting of failed TEA with extensive humeral bone loss.

The role of platelet-rich plasma in shoulder pathologies: a critical review of the literature

Platelet-rich plasma (PRP) is a revolutionary treatment that harnesses the regenerative power of the body's own platelets to promote healing and tissue regeneration. While PRP therapy has emerged as a promising option for augmenting biologic healing in the shoulder, the complexity of shoulder disorders makes it difficult to draw definitive conclusions about the efficacy of PRP across different conditions and stages of disease. Our comprehensive review of twenty-four studies highlights the current state of PRP therapy in shoulder pathologies, revealing a wide variety of number of patients, control groups and results. Despite these challenges, the regenerative potential of PRP therapy is moderate in some conditions, with numerous studies demonstrating the positive effects. In conclusion, the authors of this study recommend the use of PRP therapy for adhesive capsulitis and rotator cuff repair of medium to large tears. However, they do not recommend the use of PRP for subacromial impingement or rotator cuff tears. It is up to the clinician's discretion to decide whether PRP therapy is appropriate for individual cases. However, there is still insufficient evidence to support the inclusion of PRP therapy in treatment protocols for other shoulder disorders. Therefore, further research is needed to fully explore the potential of PRP therapy in the treatment of various shoulder conditions.

The Safety of Adiponectin Receptor Agonist AdipoRon in a Rabbit Model of Arthrofibrosis

AdipoRon is an adiponectin receptor 1, 2 (ADIPOR1 and ADIPOR2) agonist with numerous reported physiological benefits in murine models of human disease, including a proposed reduction in fibrosis. However, AdipoRon has never been investigated in rabbits, which provide a robust model for orthopedic conditions. We examined the safety of intravenous (IV) AdipoRon in New Zealand White (NZW) female rabbits surgically stressed by a procedure that mimics human arthrofibrosis. Fifteen female NZW rabbits were prospectively studied using increasing AdipoRon doses based on established literature. AdipoRon was dissolved in dimethyl sulfoxide (DMSO), diluted in normal saline, and administered IV preoperatively and for 5 subsequent days postoperatively. The primary outcome was overall toxicity to rabbits, whereas secondary outcomes were change in rabbit weights and hemodynamics and defining acid-base characteristics of the drug formulation. Two rabbits expired during preoperative drug administration at 25 mg/kg. Remaining rabbits received preoperative doses of DMSO (vehicle), 2.5, 5, or 10 mg/kg of AdipoRon without complications. On postoperative day 1, one rabbit sustained a tonic-clonic seizure after their second dose of 10 mg/kg AdipoRon. The remaining 12 rabbits (4 in each group) received six serial doses of vehicle, 2.5, or 5 mg/kg of AdipoRon without adverse effects. All formulations of AdipoRon were within safe physiological pH ranges (4-5). We are the first to report the use of IV AdipoRon in a surgically stressed rabbit model of orthopedic disease. AdipoRon doses of 5 mg/kg or less appear to be well-tolerated in female NZW rabbits. Impact statement We provided the first in vivo toxicity assessment and dose optimization of a new antifibrotic experimental medication, AdipoRon, in a surgically stressed rabbit model of knee arthrofibrosis.

The epigenetic regulator BRD4 is required for myofibroblast differentiation of knee fibroblasts

Arthrofibrosis, which is characterized by excessive scar tissue and limited motion, can complicate the daily functioning of patients after total knee arthroplasty (TKA). Molecular hallmarks of arthrofibrosis include pathologic accumulation of myofibroblasts and disproportionate collagen deposition. Epigenetic mechanisms, including posttranslation modification of histones, control gene expression and may regulate fibrotic events. This study assessed the role of the bromodomain and extra-terminal (BET) proteins on myofibroblast differentiation. This group of epigenetic regulators recognize acetylated lysines and are targeted by a class of drugs known as BET inhibitors. RNA-seq analysis revealed robust mRNA expression of three BET members (BRD2, BRD3, and BRD4) while the fourth member (BRDT) is not expressed in primary TKA knee outgrowth fibroblasts. RT-qPCR and western blot analyses revealed that BET inhibition with the small molecule JQ1 impairs TGFβ1-induced expression of ACTA2, a key myofibroblast marker, in primary outgrowth knee fibroblasts. Similarly, JQ1 administration also reduced COL3A1 mRNA levels and collagen deposition as monitored by picrosirius red staining. Interestingly, the inhibitory effects of JQ1 on ACTA2 mRNA and protein expression, as well as COL3A1 expression and collagen deposition, were paralleled by siRNA-mediated depletion of BRD4. Together, these data reveal that BRD4-mediated epigenetic events support TGFβ1-mediated myofibroblast differentiation and collagen deposition as seen in arthrofibrosis. To our knowledge, these are the first studies that assess epigenetic regulators and their downstream events in the context of arthrofibrosis. Future studies may reveal clinical utility for drugs that target epigenetic pathways, specifically BET proteins, in the prevention and treatment of arthrofibrosis.

Long-Term Patient-Reported Outcomes After Arthroscopic Debridement of Grade 3 or 4 Capitellar Osteochondritis Dissecans Lesions

BACKGROUND

Arthroscopic debridement for osteochondritis dissecans (OCD) lesions of the capitellum is a relatively common and straightforward surgical option for failure of nonoperative management. However, the long-term outcomes of this procedure remain unknown.

HYPOTHESIS

Arthroscopic debridement of capitellar OCD would provide satisfactory long-term improvement in patient-reported outcomes.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients aged ≤18 years who underwent arthroscopic debridement procedures for OCD lesions (International Cartilage Repair Society grades 3 and 4) were identified. Procedures included loose body removal when needed and direct debridement of the lesion; marrow stimulation with drilling or microfracture was added at the discretion of each surgeon. The cohort consisted of 53 elbows. Patient evaluation included visual analog scale for pain; motion; subjective satisfaction; Quick Disabilities of the Arm, Shoulder and Hand (QuickDASH) scores; reoperation; and rate of return to sports.

RESULTS

At a mean 11 years of follow-up (range, 5-23 years), the median visual analog scale score for pain was 0, and 96% of patients reported being improved as compared with how they were before surgery. The mean ± SD QuickDASH score was 4 ± 9 points (range, 0-52 points), and 80% of patients returned to their sports of interest. The arc of motion significantly improved from 115°± 28° preoperatively to 130°± 17° at latest follow-up (P = .026). Seven elbows (13%) required revision surgery for OCD lesions, resulting in high rates of overall survivorship free of revision surgery: 90% (95% CI, 80%-96%) at 5 years and 88% (95% CI, 76%-94%) at 10 years. At final follow-up, 7 all-cause reoperations were performed without revision surgery on the OCD lesion.

CONCLUSION

Arthroscopic debridement of grade 3 or 4 OCD lesions of the capitellum produced satisfactory patient-reported outcomes in a majority of elbows, although a subset of patients experienced residual symptoms. The inherent selection bias of our cohort should be considered when applying these results to the overall population with OCD lesions, as we do not recommend this procedure for all patients.

Knee immobilization reproduces key arthrofibrotic phenotypes in mice

AIMS

As has been shown in larger animal models, knee immobilization can lead to arthrofibrotic phenotypes. Our study included 168 C57BL/6J female mice, with 24 serving as controls, and 144 undergoing a knee procedure to induce a contracture without osteoarthritis (OA).

METHODS

Experimental knees were immobilized for either four weeks (72 mice) or eight weeks (72 mice), followed by a remobilization period of zero weeks (24 mice), two weeks (24 mice), or four weeks (24 mice) after suture removal. Half of the experimental knees also received an intra-articular injury. Biomechanical data were collected to measure passive extension angle (PEA). Histological data measuring area and thickness of posterior and anterior knee capsules were collected from knee sections.

RESULTS

Experimental knees immobilized for four weeks demonstrated mean PEAs of 141°, 72°, and 79° after zero, two, and four weeks of remobilization (n = 6 per group), respectively. Experimental knees demonstrated reduced PEAs after two weeks (p < 0.001) and four weeks (p < 0.0001) of remobilization compared to controls. Following eight weeks of immobilization, experimental knees exhibited mean PEAs of 82°, 73°, and 72° after zero, two, and four weeks of remobilization, respectively. Histological analysis demonstrated no cartilage degeneration. Similar trends in biomechanical and histological properties were observed when intra-articular violation was introduced.

CONCLUSION

This study established a novel mouse model of robust knee contracture without evidence of OA. This was appreciated consistently after eight weeks of immobilization and was irrespective of length of remobilization. As such, this arthrofibrotic model provides opportunities to investigate molecular pathways and therapeutic strategies.Cite this article: Bone Joint Res 2023;12(1):58-71.

Immune cell populations differ in patients undergoing revision total knee arthroplasty for arthrofibrosis

Arthrofibrosis following total knee arthroplasty (TKA) is a debilitating condition typically diagnosed based on clinical findings. To gain insight into the histopathologic immune cell microenvironment of arthrofibrosis, we assessed the extent of tissue fibrosis and quantified immune cell populations in specific tissue regions of the posterior capsule. We investigated specimens from three prospectively-collected, matched cohorts, grouped as patients receiving a primary TKA for osteoarthritis, revision TKA for arthrofibrosis, and revision TKA for non-arthrofibrotic, non-infectious reasons. Specimens were evaluated using hematoxylin and eosin staining, picrosirius red staining, immunofluorescence, and immunohistochemistry with Aperio®-based digital image analysis. Increased collagen deposition and increased number of α-SMA/ACTA2 expressing myofibroblasts were present in the arthrofibrosis group compared to the two non-arthrofibrotic groups. CD163 + macrophages were the most abundant immune cell type in any capsular sample with specific enrichment in the synovial tissue. CD163 + macrophages were significantly decreased in the fibrotic tissue region of arthrofibrosis patients compared to the patients with primary TKA, and significantly increased in adipose tissue region of arthrofibrotic specimens compared to non-arthrofibrotic specimens. Synovial CD117 + mast cells were significantly decreased in arthrofibrotic adipose tissue. Together, these findings inform diagnostic and targeted therapeutic strategies by providing insight into the underlying pathogenetic mechanisms of arthrofibrosis.

Acute versus delayed radial head arthroplasty for the treatment of radial head fractures

BACKGROUND

Radial head arthroplasty (RHA) is an important tool in the acute treatment of comminuted radial head and neck fractures. RHA is also performed in a delayed manner after failed open reduction and internal fixation, for fracture malunion or nonunion, and other chronic post-traumatic elbow disorders where restoration of the lateral column of the elbow is considered necessary. The relative efficacy and longevity of acute vs. delayed RHA is unknown. We sought to compare clinical, radiographic, and patient-reported outcomes between these groups.

METHODS

We identified patients ≥18 years old who underwent an RHA between 2000 and 2018 and then extracted 135 total elbows with a mean follow-up of 2.3 years that sustained isolated radial head fractures (30%), terrible triad injuries (66%), or Essex-Lopresti injuries (4%). The acute cohort (RHA: <12 weeks) contained 101 elbows that underwent surgery at a mean of 0.6 weeks (range, 0 days to 7 weeks, 96% <2 weeks) from injury, whereas the delayed cohort (RHA: 12 weeks to 2 years) contained 34 elbows that underwent surgery at a mean of 36 weeks (range, 14-82 weeks) from injury. Patients in the acute group had a higher percentage of terrible triad injuries (75% vs. 40%, P < .001) and Mason 3 fractures (98% vs. 45%, P < .001).

RESULTS

At the final follow-up, 13 of 101 patients in the acute cohort (13%) and 7 of 34 patients in the delayed cohort (21%) required implant revision or resection. A total of 25 patients (25%) in the acute cohort and 12 patients (35%) in the delayed cohort required a reoperation. Kaplan-Meier 2-year survival estimates free of implant resection or revision (90% acute, 86% delayed) and reoperation (76% acute, 70% delayed) were similar between groups. In patients with 5-year follow-up, there was an increased rate of revision or resection in the delayed group (30% vs. 13%). Two-year survival estimates free of radiographic loosening were 80% in the acute cohort vs. 57% in the delayed cohort (P = .04). Mayo Elbow Performance Score at 2 years demonstrated mean scores of 83 and 79 in the acute and delayed groups, respectively, with 71% of the acute cohort and 64% of the delayed cohort achieving good or excellent scores.

CONCLUSIONS

Our results demonstrated that although 2-year Kaplan-Meier survival free of revision or resection estimates and reoperation rates was equivalent between the groups, the delayed group experienced worse Mayo Elbow Performance Score outcomes, a higher revision or resection rate at 5 years, and an increased rate of radiographic loosening.

Two-stage reimplantation for deep infection after total elbow arthroplasty

Background

Persistent infection rate after 2-stage reimplantation complicating elbow arthroplasty has been reported to be as high as 25%. The purposes of this retrospective study were to determine the infection eradication rates, complications and outcomes in a cohort of patients treated with two-stage reimplantation for deep periprosthetic joint infection (PJI) following total elbow arthroplasty (TEA) and to determine possible associated risk factors for treatment failure.

Methods

Between 2000 and 2017, 52 elbows underwent a two-stage reimplantation for PJI after TEA. There were 22 males and 30 females with a mean age of 61 (range, 25-82) years. The most common bacterium was Staphylococcus epidermidis (28 elbows). Mayo Elbow Performance Scores were calculated at the latest follow-up. Mean follow-up time was 6 years (range, 2-14 years).

Results

PJI was eradicated in 36 elbows (69%). The remaining 16 elbows were considered treatment failures secondary to recurrent infection. The risk of persistent infection was 3.3 times higher in elbows with retained cement (p 0.04), and 3.5 times higher when the infecting organism was Staphylococcus epidermidis (p 0.06).

Conclusion

Two-stage reimplantation for PJI after TEA was successful in eradicating deep infection in 69% of cases. The eradication of PJI after TEA still needs to be improved substantially.

Incidence and Epidemiology of Symptomatic Capitellar Osteochondritis Dissecans of the Elbow: A United States Population-Based Study Over a 25-Year Period

Background

There are limited data on the incidence of capitellar osteochondritis dissecans (OCD) in the United States (US) population.

Purpose

To determine the incidence of symptomatic capitellar OCD in a representative US subpopulation and identify changes in its incidence over time and to investigate the relationship between the incidence of capitellar OCD and patient sex and age.

Study Design

Descriptive epidemiology study.

Methods

A retrospective review was performed of patients aged ≤24 years from Olmsted County, Minnesota, with symptomatic capitellar OCD over a 25-year period (1995-2019). Patients with acute osteochondral injuries, Panner disease, and hereditary arthropathy were excluded. Poisson regression was utilized to identify the predictors of a capitellar OCD diagnosis. Incidence rates (per 100,000) were assessed for changes over time. Age groups of younger (10-15 years) versus older (16-24 years) patients were compared.

Results

A total of 45 patients (78% male) were identified. The mean age was 14.5 years (range, 10-24 years); 31 patients were in the younger group, and 14 patients were in the older group. Sport participation was seen in 89%of patients; 90% were overhead athletes, and 58% were throwing athletes. The incidence of capitellar OCD was 6.0 per 100,000 overall, 9.5 per 100,000 for male patients, and 2.6 per 100,000 for female patients. The incidence was highest for male patients in the younger group (15.3/100,000) and lowest for female patients in the older group (0.8/100,000). The estimated incidence rate ratio for younger versus older patients was 3.3 (P < .001), and the incidence rate ratio for male versus female patients was 3.5 (P < .001). There were no changes in the incidence of capitellar OCD over time as a continuous or 5-year categorical variable (P = .290 and P = .460, respectively). Overall, 82% of patients were treated surgically. There were no significant changes in surgical rates over time.

Conclusion

In this US subpopulation, the overall incidence of symptomatic capitellar OCD between the ages of 10 and 24 years was 6.0 per 100,000 over the 25-year period studied, which is higher than previously reported US estimates. Incidence rates and treatment strategies did not change significantly over time.

Venothromboembolism following shoulder arthroscopy: a systematic review

Background

Venous thromboembolic events (VTEs) following orthopedic surgery may lead to serious morbidity and mortality. Fortunately, VTEs following upper extremity procedures are uncommon. However, the true incidence is likely underreported. The aim of this study is to provide a systematic review, excluding large database studies, to report on the incidence of VTEs following shoulder arthroscopic procedures.

Methods

Following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines, a systematic review of multiple databases was performed. A comprehensive search of several databases from inception to September 1, 2021, limited to English language and excluding animal studies, was designed and conducted. Studies were screened by 2 independent reviewers. A decision to exclude studies from large surgical or insurance claim databases was made to minimize the risk of including overlapping data points in this systematic review.

Results

Thirteen studies met inclusion and exclusion criteria and form part of this systematic review. A total of 32,407 patients were included in this study. Among these patients, the deep vein thrombosis, pulmonary embolism, and overall VTE rates were 0.15%, 0.08%, and 0.21%, respectively. Among the patients specified to have undergone arthroscopic rotator cuff repair, the rate of deep vein thrombosis, pulmonary embolism, and overall VTE was 0.71%, 0.37%, and 1.04%, respectively.

Conclusion

While symptomatic VTEs are rare following shoulder arthroscopic procedures, surgeons must be aware that they still account for a certain number of postoperative complications. Factors such as operative time, open procedures, obesity, and altitude may increase the risk of postoperative VTE although conflicting data exist. Current literature supports the idea that chemical antithrombotic prophylaxis likely provides no significant advantage over early mobilization in reducing VTEs following shoulder arthroscopy in low-risk patients.

Does proximal versus distal injury location of the medial ulnar collateral ligament of the elbow differentially impact elbow stability? An ultrasound-guided and robot-assisted biomechanical study

BACKGROUND

The location (proximal vs. distal) of elbow medial ulnar collateral ligament (MUCL) tears impacts clinical outcomes of nonoperative treatment. The purposes of our study were to (1) determine whether selective releases of the MUCL could be performed under ultrasound (US) guidance without disrupting overlying soft tissues, (2) assess the difference in medial elbow stability for proximal and distal releases of the MUCL using stress US and a robotic testing device, and (3) elucidate the flexion angle that resulted in the greatest amount of medial elbow laxity after MUCL injury.

METHODS

Sixteen paired, fresh-frozen elbow specimens were used. Valgus laxity was evaluated with both US and robotic-assisted measurements before and after selective MUCL releases. A percutaneous US-guided technique was used to perform proximal MUCL releases in 8 elbows and to perform distal MUCL releases in their matched pairs. The robot was used to determine the elbow flexion angle at which the maximum valgus displacement occurred for both proximally and distally released specimens. Open dissection was then performed to assess the accuracy of the percutaneous releases.

RESULTS

Percutaneous US-guided releases were successfully performed in 15 of 16 specimens. The proximal release resulted in greater valgus angle displacement (11° ± 2°) than the distal release (8° ± 2°) between flexion angles of 30° and 70° (P < .0001 at 30°, P < .0001 at 40°, P = .001 at 50°, P = .005 at 60°, and P = .020 at 70°). Valgus displacement between release locations did not reach the level of statistical significance between 80° and 120° (P = .051 at 80°, P = .131 at 90°, P = .245 at 100°, P = .400 at 110°, and P = .532 at 120°). When we compared the values for the mean increase in US delta gap (stressed - supported state) from before to after MUCL release, the proximally released elbows had larger increases than the distally released elbows (5.0 mm proximal vs. 3.7 mm distal, P = .032). After MUCL release, maximum mean valgus displacement occurred at 49° of flexion.

CONCLUSIONS

US-guided selective releases of the MUCL can be performed reliably without violating the overlying musculature. Valgus instability is not of greater magnitude for distal releases when compared with proximal releases. This findings suggests there must be alternative factors to explain the difference in clinical prognosis between distal and proximal tears. The observed flexion angle for maximum valgus laxity could have important implications for elbow positioning during US or fluoroscopic stress examination, as well as surgical repair or reconstruction of the MUCL.

Rotator cuff repair in patients with inflammatory arthritis: satisfactory midterm outcomes

Background

We aimed to evaluate midterm patient-reported outcomes and reoperation rates following rotator cuff repair in patients with either rheumatoid arthritis (RA) or other inflammatory arthritis (nonRA-IA) diagnoses.

Methods

We identified all patients with either RA or nonRA-IA who underwent a rotator cuff repair at our institution between 2008 and 2018. IA diagnoses included RA, systemic lupus erythematosus, psoriatic arthritis, and other unspecified inflammatory arthritis. We compiled a cohort of 51 shoulders, with an average follow-up time of 7.0 years. The average age was 60 years (range 39-81), and 55% of patients were female. Patients were contacted via phone to obtain patient-reported outcomes surveys. Univariate linear regression was used to evaluate associations between patient characteristics and outcomes.

Results

A review of preoperative radiographs demonstrated that 50% of patients presented with some degree of glenohumeral joint inflammatory degeneration. At the final follow-up, the mean visual analog score for pain was 2 (range 0-8), and the mean American Shoulder and Elbow Surgeons score (ASES) was 77 (standard deviation [SD] = 19). The mean subjective shoulder value was 75% (SD = 22%), and the average satisfaction was 9 (SD 1.9). The mean Patient-Reported Outcomes Measurement Information System upper extremity score was 41 (SD = 10.6). Female sex and a complete tear (vs. partial) were both associated with lower ASES scores, whereas no other characteristics were associated with postoperative ASES scores. The 5-year Kaplan-Meier survival estimate free of reoperation was 91.8% (95% confidence interval 83.0-99.8).

Conclusions

Rotator cuff repair in patients with RA or other inflammatory arthritis diagnoses resulted in satisfactory patient-reported outcomes that seem comparable to rotator cuff repair when performed in the general population. Furthermore, reoperations were rare, with a 5-year survival rate free of reoperation for any reason of over 90%. Altogether, an inflammatory arthritis diagnosis should not preclude by itself attempted rotator cuff repair surgery in these patients.

Prospective Randomized Trial of Continuous Passive Motion Versus Physical Therapy After Arthroscopic Release of Elbow Contracture

BACKGROUND

Continuous passive motion (CPM) has been used for decades, but we are not aware of any randomized controlled trials (RCTs) in which CPM has been compared with physical therapy (PT) for rehabilitation following release of elbow contracture.

METHODS

In this single-blinded, single-center RCT, we randomly assigned patients undergoing arthroscopic release of elbow contracture to a rehabilitation protocol involving either CPM or PT. The primary outcomes were the rate of recovery and the arc of elbow motion (range of motion) at 1 year. The rate of recovery was evaluated by measuring range of motion at 6 weeks and 3 months. The secondary outcomes included other range-of-motion-related outcomes, patient-reported outcome measures (PROMs), flexion strength and endurance, grip strength, and forearm circumference at multiple time points.

RESULTS

A total of 24 patients were assigned to receive CPM, and 27 were assigned to receive PT. At 1 year, CPM was superior to PT with regard to the range of motion, with an estimated treatment difference of 9° (95% confidence interval [CI], 3° to 16°; p = 0.007). Similarly, the use of CPM led to a greater range of motion at 6 weeks and 3 months than PT. The percentage of lost motion recovered at 1 year was higher in the CPM group (51%) than in the PT group (36%) (p = 0.01). The probability of restoring a functional range of motion at 1 year was 62% higher in the CPM group than in the PT group (risk ratio for functional range of motion, 1.62; 95% CI, 1.01 to 2.61; p = 0.04). PROM scores were similar in the 2 groups at all time points, except for a difference in the American Shoulder and Elbow Surgeons (ASES) elbow function subscale, in favor of CPM, at 6 weeks. The use of CPM decreased swelling and reduced the loss of flexion strength, flexion endurance, and grip strength on day 3, with no between-group differences thereafter.

CONCLUSIONS

Among patients undergoing arthroscopic release of elbow contracture, those who received CPM obtained a faster recovery and a greater range of motion at 1 year, with a higher chance of restoration of functional elbow motion than those who underwent routine PT.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

Shoulder Periprosthetic Joint Infection and All-Cause Mortality: A Worrisome Association

Background

Periprosthetic joint infection (PJI) can be a devastating complication following shoulder arthroplasty. PJI following hip and knee arthroplasties has been found to increase mortality. However, anatomical and bacteriologic differences could potentially result in a different trend after shoulder arthroplasties. Thus, the purpose of the present study was to determine whether there is an association between shoulder PJI and all-cause mortality.

Methods

Our institutional Total Joint Registry Database was queried to identify patients who underwent revision shoulder arthroplasty procedures between 2000 and 2018. A total of 1,160 procedures were then classified as either septic (21.8%) or aseptic (78.2%). Septic revisions were further subdivided into (1) debridement, antibiotics, irrigation, and implant retention (9.1%); (2) 2-stage reimplantation for deep infection (61.3%); (3) implant resection without reimplantation (3.6%); and (4) unexpected positive cultures at revision surgery (26.1%). The most common bacterium isolated was Cutibacterium acnes (64.4%). All-cause patient mortality was determined with use of our registry and confirmed with use of a nationwide mortality database. All-cause crude and adjusted mortality rates were then compared between groups.

Results

The 1-year crude mortality rate was 1.8% (95% confidence interval [CI], 0.9% to 2.6%) for the aseptic group and 2.8% (95% CI, 0.7% to 4.8%) for the septic group (p = 0.31). Multivariate Cox regression analysis demonstrated an elevated but statistically similar adjusted hazard ratio for 1-year all-cause mortality of 1.9 (95% CI, 0.8 to 4.6) when comparing the septic to the aseptic group (p = 0.17). The risk of 2-year all-cause mortality was significantly higher in the septic group, with a hazard ratio of 2.2 (95% CI, 1.1 to 4.5; p = 0.029). In univariate analyses, increased 5-year mortality in the septic revision group was associated with age, Charlson Comorbidity Index, and methicillin-resistant Staphylococcus aureus infection, whereas C. acnes infection was associated with lower mortality.

Conclusions

Shoulder PJI is associated with an adjusted 2-year all-cause mortality rate that is double that of aseptic patients. The results of the present study should be utilized to appropriately counsel patients who are considered to be at risk for infection following shoulder arthroplasty.

Level of Evidence

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Human outgrowth knee fibroblasts from patients undergoing total knee arthroplasty exhibit a unique gene expression profile and undergo myofibroblastogenesis upon TGFβ1 stimulation

Arthrofibrosis is characterized by excessive extracellular matrix (ECM) deposition that results in restricted joint motion after total knee arthroplasties (TKAs). Currently, treatment options are limited. Therefore, an in vitro model of knee-related myofibroblastogenesis is valuable to facilitate investigation of the arthrofibrotic process, diagnostic and therapeutic options. In this study, we obtained intraoperative posterior capsule (PC), quadriceps tendon (QT), and suprapatellar pouch (SP) tissues from the knees of four patients undergoing primary TKAs for osteoarthritis. From these tissues, we isolated primary cells by the outgrowth method and subsequently characterized these cells in the absence and presence of the pro-myofibroblastic cytokine, transforming growth factor beta 1 (TGFβ1). Light microscopy of knee outgrowth cells revealed spindle-shaped cells, and immunofluorescence (IF) analysis demonstrated staining for the fibroblast-specific markers TE-7 and vimentin (VIM). These knee outgrowth fibroblasts differentiated readily into myofibroblasts as reflected by enhanced α-smooth muscle actin (ACTA2) mRNA and protein expression and increased mRNA expression of collagen type 1 (COL1A1) and type 3 (COL3A1) with collagenous matrix deposition in the presence of TGFβ1. Outgrowth knee fibroblasts were more sensitive to TGFβ1-mediated myofibroblastogenesis than adipose-derived mesenchymal stromal/stem cells (MSCs). While outgrowth knee fibroblasts isolated from three anatomical regions in four patients exhibited similar gene expression, these cells are distinct from other fibroblastic cell types (i.e., Dupuytren's fibroblasts) as revealed by RNA-sequencing. In conclusion, our study provides an in vitro myofibroblastic model of outgrowth knee fibroblasts derived from patients undergoing primary TKA that can be utilized to study myofibroblastogenesis and assess therapeutic strategies for arthrofibrosis.

Perioperative Clopidogrel (Plavix®) Continuation in Shoulder Arthroplasty: Approach Cautiously

Background

Methods

Results

Conclusion

Biomechanical, histological, and molecular characterization of a new posttraumatic model of arthrofibrosis in rats

Experimental analyses of posttraumatic knee arthrofibrosis utilize a rabbit model as a gold standard. However, a rodent model of arthrofibrosis offers many advantages including reduced cost and comparison with other models of organ fibrosis. This study aimed to characterize the biomechanical, histological, and molecular features of a novel posttraumatic model of arthrofibrosis in rats. Forty eight rats were divided into two equal groups. An immobilization procedure was performed on the right hind limbs of experimental rats. One group was immobilized for 4 weeks and the other for 8 weeks. Both groups were remobilized for 4 weeks. Limbs were studied biomechanically via assessment of torque versus degree of extension, histologically via whole knee specimen, and molecularly via gene expression of posterior capsular tissues. Significant differences were observed between experimental and control limbs at 4 N-cm of torque in the 4-week (knee extension: 115° ± 8° vs. 169° ± 17°, respectively; p = 0.007) and 8-week immobilization groups (knee extension: 99° ± 12° vs. 174° ± 9°, respectively; p = 0.008). Histologically, in each group experimental limbs demonstrated increased posterior capsular thickness and total area of tissue when compared to control limbs (p < 0.05). Gene expression values evaluated in each group were comparable. This study presents a novel rat model of arthrofibrosis with severe and persistent knee contractures demonstrated biomechanically and histologically. Statement of clinical significance: Arthrofibrosis is a common complication following contemporary total knee arthroplasties. The proposed model is reproducible, cost-effective, and can be employed for translational investigations studying the pathogenesis of arthrofibrosis and efficacy of neoadjuvant pharmacologic agents.

Predictors of reoperation after internal fixation of intra-articular distal humerus fractures

BACKGROUND

Despite good reported outcomes with open reduction and internal fixation of intra-articular distal humerus fractures, complication rates remain high. The objective of this work is to identify factors associated with reoperation.

METHODS

Sixty-three patients treated with open reduction and internal fixation for intra-articular (Arbeitsgemeinschaft für Osteosynthesefragen type C) distal humerus fractures between 2004 and 2010 were identified using an institutional trauma registry, 62 of which were followed for a minimum of six months. Age, gender, fracture subclassification, open fracture presence, Injury Severity Score, time to definitive surgery, length of postoperative immobilization, and type of approach were recorded. Multivariate analysis was utilized to identify factors independently associated with reoperation.

RESULTS

Complications requiring reoperation developed in 25 (40.3%) elbows. The most common reasons were wound dehiscence or infection in nine elbows (14.5%) and symptomatic hardware in six (9.6%). During multivariate analysis, only olecranon osteotomy remained an independent predictor for reoperation (P = 0.043).

DISCUSSION

Despite improved internal fixation techniques, a high proportion of elbows require reoperation after open reduction and internal fixation for distal humerus fractures. Higher complication rates in fractures fixed through an olecranon osteotomy may reflect additional reoperations due to nonunion of the osteotomy or need to remove hardware from the ulna.

LEVEL OF EVIDENCE

Prognostic Level III.

Autonomy and focus of attention in medical motor skills learning: a randomized experiment

BACKGROUND

The 'OPTIMAL' (Optimizing Performance Through Intrinsic Motivation and Attention for Learning) theory of motor learning suggests that autonomy, external focus of attention, and perceived competence can improve learning of simple motor tasks. The authors hypothesized that enhanced (vs. routine) autonomy and external (vs. internal) focus of attention would improve first-try performance of two medical motor tasks.

METHODS

The authors conducted a randomized two-by-two factorial design study with high school students as participants. Task instructions promoted either enhanced or routine autonomy, and either external or internal focus of attention. These conditions were replicated in a crossover design for two common medical tasks (chest compressions on a manikin and a Fundamentals of Laparoscopic Surgery peg transfer task). Primary outcomes were objective measures of task performance (chest compression deviation from target depth; peg transfer time with penalties for errors). Secondary outcomes included subjective perceptions of confidence, autonomy, and workload.

RESULTS

One hundred thirty-three high school students participated in this study. The primary outcomes concerning enhanced vs. routine autonomy demonstrated no statistically significant difference in either task (chest compression depth deviation: difference -0.7 mm [score range 0 to 37.5 mm]; 95% confidence interval (CI95) -3.85, 2.41; p = .65; peg transfer penalized time: rate ratio 1.03; CI95 0.91, 1.31; p = .79). The authors likewise found no statistically significant difference for external vs. internal focus of attention (depth deviation: difference 1.1 mm; CI95 -2.04, 4.17; p = .50; penalized time: rate ratio 0.89; CI95 0.75, 1.13; p = .33). The authors found no statistically significant differences for either comparison in confidence, autonomy and workload (p > .09; differences ranged from -0.83 to 0.79 [scale range 0 to 10]).

CONCLUSIONS

First-try performance of chest compressions and peg transfer by novice learners is not significantly affected by enhanced (vs. routine) autonomy or external (vs. internal) focus of attention.

Intra-articular celecoxib improves knee extension regardless of surgical release in a rabbit model of arthrofibrosis

Aims

Outcomes of current operative treatments for arthrofibrosis after total knee arthroplasty (TKA) are not consistently positive or predictable. Pharmacological in vivo studies have focused mostly on prevention of arthrofibrosis. This study used a rabbit model to evaluate intra-articular (IA) effects of celecoxib in treating contracted knees alone, or in combination with capsular release.

Methods

A total of 24 rabbits underwent contracture-forming surgery with knee immobilization followed by remobilization surgery at eight weeks. At remobilization, one cohort underwent capsular release (n = 12), while the other cohort did not (n = 12). Both groups were divided into two subcohorts (n = 6 each) – one receiving IA injections of celecoxib, and the other receiving injections of vehicle solution (injections every day for two weeks after remobilization). Passive extension angle (PEA) was assessed in live rabbits at 10, 16, and 24 weeks, and disarticulated limbs were analyzed for capsular stiffness at 24 weeks.

Results

IA celecoxib resulted in greater mean PEA at ten weeks (69.6° (SD 4.6) vs 45.2° (SD 9.6), p = 0.004), 16 weeks (109.8° (SD 24.2) vs 60.9° (SD10.9), p = 0.004), and 24 weeks (101.0° (SD 8.0) vs 66.3° (SD 5.8), p = 0.004). Capsular stiffness was significantly reduced with IA celecoxib (2.72 Newton per cm (N·cm)/° (SD 1.04), p = 0.008), capsular release (2.41 N·cm/° (SD 0.80), p = 0.008), and capsular release combined with IA celecoxib (3.56 N·cm/° (SD 0.99), p = 0.018) relative to IA vehicle (6.09 N·cm/° (SD 1.64)).

Conclusion

IA injections of a celecoxib led to significant improvements in passive extension angles, with reduced capsular stiffness, when administered to rabbit knees with established experimental contracture. Celecoxib was superior to surgical release, and the combination of celecoxib and a surgical release did not provide any additional value.

Cite this article: Bone Joint Res 2022;11(1):32–39.

Total elbow arthroplasty for tumors of the distal humerus and elbow

INTRODUCTION

The elbow is a rare location for primary and metastatic tumors in the upper extremity. The goal of reconstruction is to provide painless motion and stability for hand function. Total elbow arthroplasty (TEA) is commonly utilized, with either off-the-self components, modular segmental endoprosthesis, or allograft-prosthesis composites (APC). The purpose of this study was to analyze and compare commonly utilized elbow reconstructions and report outcomes of (1) patient function and (2) implant survival and complications.

METHODS

We reviewed 33 patients (18 females and 15 males) undergoing elbow arthroplasty for reconstruction of an underlying oncologic process including linked TEA (n = 22, 67%), APC (n = 9, 27%), and endoprosthesis (n = 2, 6%). The most common indication was metastatic disease (n = 17, 52%), with 24 patients (73%) presenting with a pathologic fracture.

RESULTS

Five-year implant survival was following elbow reconstruction was 88%. The mean most recent Mayo Elbow Performance Score and Musculoskeletal Tumor Society Score were 84 ± 18 and 78 ± 15%. Postoperative complications occurred in 15 elbows (45%), most commonly periprosthetic fracture (n = 5, 15%), leading to reoperation in six elbows (18%).

CONCLUSION

Although elbow arthroplasty is associated with a high incidence of complications, it provides a stable platform for upper extremity function in patients with oncologic processes of the elbow.

A review of the surgical management of distal humerus fractures and nonunions: From fixation to arthroplasty

Distal humeral fractures in adults are challenging injuries. They often require surgical intervention in form of internal fixation or total elbow arthroplasty which is being increasingly used in physiologically elderly patients with comminuted fractures. Careful preoperative evaluation including type of fracture, quality of bone, pre-existing conditions and functional demand help in deciding optimal treatment. CT scans including 2D and 3D reconstructions are almost mandatory in proper planning of the surgical treatment. In most cases with a healthy physiologically young patient, ORIF is the treatment of choice. Biomechanical studies have shown that parallel plating resists rotational deformity to a greater degree than 90/90 plating allowing supracondylar union. Accurate realignment of articular fragments and compression at the supracondylar area is key to the success of the internal fixation. Main cause of failure of fixation is the nonunion or malunion in the supracondylar area. The principles described by O'Driscoll et al. allow for rigid fixation of the distal articular fragments and compression at the supracondylar level which is vital to healing and the prevention of hardware failure, and nonunion. Olecranon osteotomy improves the expodure of distal humeral articular surface but has its own share of problems and should be avoided if possible. Irritation of ulnar nerve is a common complication so it should be isolated, kept under vision throughout and if necessary, transposed anteiriorly. Nonunion or malunion of supracondylar fractures can be treated by revision ORIF or total elbow arthroplasty (TEA). Supracondylar shortening, bone grafting and contracture release are important elements of treatment of nonunions. In unreconstructable distal humerus fractures, where open reduction and internal fixation is not possible due to the small size of the fragments, severe comminution and/or poor bone quality, TEA is the treatment of choice. Triceps can be left intact as the excision of fractured fragments usually provide enough space to carry out the operation. Sometimes, the decision to perform TEA is only made after exposing the fracture so the surgeon should be comfortable in performing TEA if ORIF is not possible; and necessary instruments and implants should be available on the shelf. In spite of satisfactory outcome, overall complication rate after TEA remains high and makes surgical efficiency and technical competence of utmost importance.

Return to Sports After Primary Reverse Shoulder Arthroplasty: Outcomes at Mean 4-Year Follow-up

Background:

With the expanding use of reverse shoulder arthroplasty (RSA) to treat various shoulder conditions, there has been a rise in the number of RSAs performed, especially in physically active patients. Limited information regarding sports after RSA is available to properly counsel patients on postoperative expectations.

Purpose:

To assess the rate of return to sports as well as the ability to return to the same level of preoperative intensity, frequency, and duration of sport after primary RSA.

Study Design:

Case series; Level of evidence, 4.

Methods:

This was a retrospective review of patients who underwent primary RSA at our institution between 2014 and 2016. Shoulder motion, Subjective Shoulder Value score, American Shoulder and Elbow Surgeons score, pre- and postoperative sports activities, and barriers to return to sport were assessed in 109 patients after RSA (93 patients with unilateral RSA and 16 patients with bilateral RSA). The mean age at the time of surgery was 70 years (range, 34-86 years), with a mean follow-up of 3.9 years (range, 2-12 years).

Results:

The mean rate of return to sports was 70.1% (range, 0%-100%). There was no difference in return to sports between those with uni- and bilateral RSA (P = .64). Fishing, swimming, elliptical/treadmill, and hunting were the most common sports after RSA with return rates of 91%, 73%, 86%, and 82% respectively. A majority of patients returned to the same level of preoperative intensity, frequency, and duration for all sports except for climbing and swimming. There was a lower mean rate of return for high-demand sports (62.9%) compared with low- and medium-demand sports (76.7%) (P = .005). The most common reasons for inability to return to sports included limited motion, fear of injury, and weakness.

Conclusion:

Patients who had undergone primary uni- or bilateral RSA reported a 70.1% rate of return to sports with maintenance of the same level of intensity, duration, and frequency of preoperative sport participation. Rates of return to high-demand sports were lower than low- and medium-demand sports. Patients also had difficulty returning to overhead sports.

Radial Head Replacement for Acute Radial Head Fractures: Outcome and Survival of Three Implant Designs With and Without Cement Fixation

OBJECTIVES

To determine outcomes of radial head replacement (RHR) for acute fractures using 3 different implant designs with or without cement fixation.

DESIGN

Retrospective.

SETTING

Tertiary referral hospital.

PATIENTS/PARTICIPANTS

One hundred fourteen elbows underwent RHR for an acute radial head fracture using either (1) a nonanatomic design and smooth stem (n = 60), (2) a nonanatomic design with a grit-blasted, ingrowth, curved stem (n = 21), or (3) an anatomic design with a grit-blasted ingrowth straight stem (n = 33). Cemented (25%) or uncemented (75%) fixation was used at the discretion of the treating surgeon.

INTERVENTION

RHR.

MAIN OUTCOME MEASUREMENTS

The primary outcome was implant survivorship free of revision or removal for any reason. All elbows were evaluated clinically (the Mayo Elbow Performance Score and reoperations/complications) and radiographically.

RESULTS

Fourteen implants (12%) were revised. Of elbows with a minimum 2-year clinical follow-up, the average Mayo Elbow Performance Score was 88. The rate of survivorship free from revision was 92% [95% confidence interval (CI) = 87%-98%] at 2 years, 90% (CI = 84%-96%) at 5 years and 84% (CI = 75%-94%) at 10 years. The differences in survivorship between the 3 implants did not reach statistical significance, but the nonanatomic design with a grit-blasted ingrowth curved stem had a hazard ratio of 4.6 (95% CI = 0.9%-23%) for failure. There were no differences in survivorship between cemented versus uncemented stems. For those elbows with a minimum of 2 years of radiographic follow-up, implant tilt was observed in 10 (16%) elbows and loosening in 16 (26%) elbows. Stress shielding was present in 19 (42%) of well-fixed implants.

CONCLUSIONS

RHR for acute trauma leads to survivorship greater than 80% at 10 years. Radiographic changes (loosening, stress shielding, and implant tilting) can be expected in a substantial portion of elbows at long-term follow-up.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Elevated Expression of Plasminogen Activator Inhibitor (PAI-1/SERPINE1) is Independent from rs1799889 Genotypes in Arthrofibrosis

Arthrofibrosis is characterized by excessive extracellular matrix deposition in patients with total knee arthroplasties (TKAs) and causes undesirable joint stiffness. The pathogenesis of arthrofibrosis remains elusive and currently there are no diagnostic biomarkers for the pathological formation of this connective tissue. Fibrotic soft tissues are known to have elevated levels of plasminogen activator inhibitor-1 (PAI-1) (encoded by SERPINE1), a secreted serine protease inhibitor that moderates extracellular matrix remodeling and tissue homeostasis. The 4G/5G insertion/deletion (rs1799889) is a well-known SERPINE1 polymorphism that directly modulates PAI-1 levels. Homozygous 4G/4G allele carriers typically have higher PAI-1 levels and may predispose patients to soft tissue fibrosis (e.g., liver, lung, and kidney). Here, we examined the genetic contribution of the SERPINE1 rs1799889 polymorphism to musculoskeletal fibrosis in arthrofibrotic (n = 100) and non-arthrofibrotic (n = 100) patients using Sanger Sequencing. Statistical analyses revealed that the allele frequencies of the SERPINE1 rs1799889 polymorphism are similar in arthrofibrotic and non-arthrofibrotic patient cohorts. Because the fibrosis related SERPINE1 rs1799889 polymorphism is independent of arthrofibrosis susceptibility in TKA patients, the possibility arises that fibrosis of joint connective tissues may involve unique genetic determinants distinct from those linked to classical soft tissue fibrosis.

Humeral amputation following total elbow arthroplasty

PURPOSE

Total elbow arthroplasty (TEA) is associated with a relatively high complication rate, and exceptionally catastrophic complications might lead to amputation. The purpose of this study was to determine the incidence and aetiology of amputation performed at our institution in upper extremity limbs with a prior TEA.

METHODS

Between 1973 and 2018, 1906 consecutive TEAs were performed at our institution. Upper extremity amputation was performed in seven (0.36%) elbows with five transhumeral amputations and two shoulder disarticulations. The group consisted of five females and two males with a mean age of 64 years (range, 37-80). The index TEA had been performed for rheumatoid arthritis (n = 2), rheumatoid arthritis with acute fracture (n = 2), radiation associated nonunion (n = 2), and metastatic cancer (n = 1). Mean follow-up after amputation was three years (range, 3 months-5 years).

RESULTS

Mean time between amputation and TEA was 5 years (range, 2 months-13 years). The indications for amputation included uncontrolled deep infection in six (86%) elbows and tumor recurrence in one (14%) elbow. Only one elbow (14%) was fitted with a prosthesis. Six (86%) patients died at a mean of three years (range, 3 months-5 years) after amputation.

CONCLUSION

The results of this study highlight a low incidence of amputation after TEA. Most amputations were the direct result of TEA complications, with infection being the most common cause of amputation. Outcomes after amputation are concerning, with poor overall survival and few patients being fit for a prosthesis.

Revision Elbow Arthroplasty Using a Proximal Ulnar Allograft with Allograft Triceps for Combined Ulnar Bone Loss and Triceps Insufficiency

BACKGROUND

When revision elbow arthroplasty is required in the presence of structural proximal ulnar bone loss and triceps insufficiency, structural ulnar bone-grafting and triceps reconstruction are both required to reconstruct the skeleton and to restore active extension. We have developed a technique utilizing a structural proximal ulnar allograft with its attached triceps as an allograft-prosthetic composite (APC) to provide reconstruction of the proximal ulnar bone and deficient extensor mechanism with the same allograft.

METHODS

Between 2010 and 2017, the senior author performed 10 revision elbow arthroplasties using a proximal ulnar allograft with its intact triceps tendon allograft. The allograft ulna was combined with an ulnar component in an APC fashion, whereas the remaining triceps was repaired to the triceps allograft. Indications for a revision surgical procedure included aseptic loosening in 4 elbows, periprosthetic ulnar fracture with component loosening in 2 elbows, and the second stage of a 2-stage reimplantation in 4 elbows. Two elbows also required humeral APCs due to associated structural humeral bone loss. Postoperatively, all elbows were immobilized in extension for 6 weeks. The mean follow-up time was 45 months (range, 24 to 76 months).

RESULTS

Revision elbow arthroplasty resulted in pain improvement in all elbows in a 10-point visual analog scale. The mean flexion-extension arc was 95°, the mean Mayo Elbow Performance Score was 76 points (range, 45 to 95 points), and the mean triceps strength score was 4. There were 6 reoperations: 3 for humeral loosening, 1 for deep infection, 1 for fracture of the ulnar allograft, and 1 for wound debridement and closure. For the 8 elbows with an intact ulnar reconstruction, no ulnar components were radiographically loose, and the ulnar graft was considered radiographically intact and healed in 8 elbows.

CONCLUSIONS

Reconstruction of the proximal part of the ulna and triceps in failed elbow arthroplasties with structural ulnar bone loss can be effectively accomplished using a structural proximal ulnar allograft as an APC with the preserved triceps tendon for the extensor mechanism reconstruction, but the procedure is associated with an expected high reoperation rate, as is the case in complex revision elbow arthroplasty.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Reduction of arthrofibrosis utilizing a collagen membrane drug-eluting scaffold with celecoxib and subcutaneous injections with ketotifen

The dense formation of abnormal scar tissue after total knee arthroplasty results in arthrofibrosis, an unfortunate sequela of inflammation. The purpose of this study was to use a validated rabbit model to assess the effects on surgically-induced knee joint contractures of two combined pharmacological interventions: celecoxib (CXB) loaded on an implanted collagen membrane, and subcutaneously (SQ) injected ketotifen. Thirty rabbits were randomly divided into five groups. The first group received no intervention after the index surgery. The remaining four groups underwent intra-articular implantation of collagen membranes loaded with or without CXB at the time of the index surgery; two of which were also treated with SQ ketotifen. Biomechanical joint contracture data were collected at 8, 10, 16, and 24 weeks. At the time of necropsy (24 weeks), posterior capsule tissue was collected for messenger RNA and histopathologic analyses. At 24 weeks, there was a statistically significant increase in passive extension among rabbits in all groups treated with CXB and/or ketotifen compared to those in the contracture control group. There was a statistically significant decrease in COL3A1, COL6A1, and ACTA2 gene expression in the treatment groups compared to the contracture control group (P < .001). Histopathologic data also demonstrated a trend towards decreased fibrous tissue density in the CXB membrane group compared to the vehicle membrane group. The present data suggest that intra-articular placement of a treated collagen membrane blunts the severity of contracture development in a rabbit model of arthrofibrosis, and that ketotifen and CXB may independently contribute to the prevention of arthrofibrosis. Statement of clinical significance: Current literature has demonstrated that arthrofibrosis may affect up to 5% of primary total knee arthroplasty patients. For that reason, novel pharmacologic prophylaxis and treatment modalities are critical to mitigating reoperations and revisions while improving the quality of life for patients with this debilitating condition.

Human Fibrosis: Is There Evidence for a Genetic Predisposition in Musculoskeletal Tissues?

BACKGROUND

Pathologic fibrosis is characterized by dysregulation of gene expression with excessive extracellular matrix production. The genetic basis for solid organ fibrosis is well described in the literature. However, there is a paucity of evidence for similar processes in the musculoskeletal (MSK) system. The purpose of this review is to provide an overview of existing evidence of genetic predisposition to pathologic fibrosis in the cardiac, pulmonary, and MSK systems, and to describe common genetic variants associated with these processes.

METHODS

A comprehensive search of several databases from 2000 to 2019 was conducted using relevant keywords in the English language. Genes reported as involved in idiopathic fibrotic processes in the heart, lung, hand, shoulder, and knee were recorded by 2 independent authors.

RESULTS

Among 2373 eligible studies, 52 studies investigated genetic predisposition in terms of variant analysis with the following organ system distribution: 36 pulmonary studies (69%), 15 hand studies (29%), and 1 knee study (2%). Twenty-two percent of gene variants identified were associated with both pulmonary and MSK fibrosis (ie, ADAM, HLA, CARD, EIF, TGF, WNT, and ZNF genes). Genetic variants known to be involved in the MSK tissue development or contractility properties in muscle were identified in the pulmonary fibrosis.

CONCLUSION

Despite shared genetic variations in both the lung and hand, there remains limited information about genetic variants associated with fibrosis in other MSK regions. This finding establishes the necessity of further studies to elucidate the genetic determinants involved in the knee, shoulder, and other joint fibrotic pathways.

LEVEL OF EVIDENCE

Level III.

Establishing the learning curve for elbow arthroscopy: surgeon and trainee perspectives on number of cases needed and optimal methods for acquiring skill

BACKGROUND

Elbow arthroscopy has increased in frequency as its indications have widened. Despite this growth, a learning curve has not yet been defined.

HYPOTHESIS

We hypothesized that there would be significant differences in perspective between trainees and established surgeons for the number of cases needed to reach each skill level and what they felt are the most valuable training tools.

METHODS

Orthopedic attending physicians and trainees were asked to complete a questionnaire assessing participant demographics, case volumes required to reach defined skill levels (novice, safe, competent, proficient, and expert), and the efficacy of various learning methodologies for elbow arthroscopy. The value of educational methods was assessed using a 5-point Likert scale (1 = not at all valuable; 5 = extremely valuable).

RESULTS

The study population consisted of 323 total participants, of whom 224 (69.3%) were attending surgeons and 99 (30.7%) were trainees (resident or fellow physicians). According to the attending physicians, the mean numbers of cases needed to reach each skill level were 19 to be safe, 42 to be competent, 93 to be proficient, and 230 to be expert. These case numbers were not significantly different from the perspectives of trainees. Across the respondents, there were no significant differences in the number of cases needed to reach each level of skill based on the respondents' level of training, years of experience, type of fellowship, or self-reported skill level.Although both groups highly valued live surgery (4.7 of 5) and cadaveric practice (4.6 of 5) for acquiring skill, attendings placed higher value on reading (4.0 vs. 3.3, P < .001), videos/live demos (4.2 vs. 3.6, P < .001), and formal courses (4.5 vs. 4.1, P < .001) than trainees. Both groups place relatively low value on surgical simulators (2.8-3.6).

CONCLUSIONS

There was considerable agreement among attending surgeons and trainees in terms of the number of cases needed to attain various skill levels of elbow arthroscopy, which was consistent regardless of fellowship background, self-reported skill level, career length, and elbow arthroscopy case volume. However, there was some disagreement between attending surgeons and trainees over the most valuable methods for acquiring surgical skill with trainees placing less value on textbooks, surgical videos, and formal courses compared with attending surgeons. An understanding of the elbow arthroscopy learning curve will help trainees and their training programs establish case volume targets before safe, independent practice. Future studies should aim to clinically validate this learning curve.

Comparison of reconstructive techniques following oncologic intraarticular resection of proximal humerus

INTRODUCTION

The proximal humerus is a common site of primary and metastatic disease in the upper extremity. Historically, the goal of a hemiarthroplasty reconstruction was to provide a stable platform for hand and elbow function, with limited shoulder function. Techniques utilizing a reverse endoprosthesis (endoprosthetic replacement [EPR]) and allograft-prosthetic composite (APC) have been developed; however, there is a paucity of comparative studies.

METHODS

A total of 83 (42 females, 41 males) patients undergoing an intraarticular resection of the humerus were reviewed. Reconstructions included 30 reverse and 53 hemiarthroplasty; including hemiarthroplasty EPR (n = 36) and APC (n = 17), and reverse EPR (n = 20) and APC (n = 10).

RESULTS

Reverse reconstructions had improved forward elevation (85° vs. 44°, p < .001) and external rotation (30° vs. 21°; p < .001) versus a hemiarthroplasty. Reverse reconstructions had improved American Shoulder and Elbow Surgeons scores (65 vs. 57; p = .01) and Musculoskeletal Tumor Society 93 scores (72 vs. 63; p < .001) versus hemiarthroplasty. Subluxation of the reconstruction was a common (n = 23, 27%), only occurring in hemiarthroplasty patients (EPR [n = 13, 36%] and APC [n = 10, 59%]).

CONCLUSION

The current series highlights the improved functional outcome in patients undergoing reconstruction with a reverse arthroplasty compared to the traditional hemiarthroplasty. Currently reverse shoulder arthroplasty (APC or EPR) is our preferred methods of reconstruction in this patient population.