Shoulder arthroplasty after prior external beam radiation therapy: a matched cohort analysis.

BACKGROUND: External beam radiation therapy (XRT) is a commonly used therapeutic modality for the treatment of various chest wall and axillary malignancies. Despite the known risk of local soft tissue dysfunction, and possibly compromised bone ingrowth for cementless implants, there remains limited data on the impact of prior XRT in a shoulder arthroplasty (SA) cohort. This study evaluated the outcomes of primary SA in patients with prior XRT compared to a matched cohort (MC). METHODS: Over a 27-year time period (1993-2020), 80 primary SAs (7 hemiarthroplasties [HAs], 29 anatomic total shoulder arthroplasties [aTSAs], and 44 reverse shoulder arthroplasties [rTSAs]) with previous XRT to the upper chest or axillary region and a minimum of 2-year follow-up were included. This cohort was matched (1:2) according to age, sex, body mass index (BMI), implant, and year of surgery with patients who had undergone HA or TSA for osteoarthritis or RSA for cuff tear arthropathy. Clinical outcomes including pain, active shoulder range of motion (ROM), strength, complications, and reoperations inclusive of revision surgery were assessed. RESULTS: The XRT cohort consisted of 71 (88.8%) women with a mean age of 70.9 (range, 43-87) years, BMI of 30.9 ± 7.6, and follow-up period of 6.6 years (range, 2.0-28.2). In these patients, SA led to substantial improvements in pain, ROM, and strength across the entire cohort. When compared to the MC, the XRT group demonstrated a lower final postoperative forward elevation (FE) (111° vs. 126°; P = .013) and less improvements in pain (5.3 vs. 6.2; P = .002), FE (34° vs. 54°; P = .002), and external rotation (13° vs. 24°; P < .001). There were 14 (17.5%) complications and 7 reoperations in the XRT group, with rotator cuff failure after HA or TSA (n = 4 of 36; 11.1%) as the most common complication and no instances of loose humeral components. The XRT group had a higher rate of complications (17.5% vs. 8.1%; P = .03) but not reoperations (8.8% vs. 3.1%; P = .059). When evaluated by implant, rTSA demonstrated the lowest rate of reoperations followed by aTSA and HA (2.3% vs. 10.3% vs. 42.9%; P = .002). CONCLUSIONS: Primary SA is an effective treatment modality for the improvement of pain, motion, and strength in patients with a history of prior XRT. However, when compared to patients without prior XRT, less clinical improvement and a higher rate of postoperative complications were observed.

Shoulder arthroplasty after prior anterior shoulder instability surgery: a matched cohort analysis.

PURPOSE: To evaluate the effect of prior anterior shoulder instability surgery (SIS) on the outcomes and complications of primary anatomic total shoulder arthroplasty (aTSA) and reverse total shoulder arthroplasty (rTSA). METHODS: Between 2007 and 2018, 38 primary total shoulder arthroplasties (TSA) (22 aTSA and 16 rTSA) with a prior SIS and a minimum of 2 years of follow-up were identified. This cohort was matched 1:3 based on age, sex, body mass index, year of surgery, and dominant shoulder. aTSA and rTSA were matched to patients with primary osteoarthritis (OA) and rotator cuff tear arthropathy (CTA), respectively. RESULTS: TSA produced similar postoperative pain, ROM, patient-reported outcome measures, complications, and revisions in those with prior SIS vs. controls. aTSA with prior SIS demonstrated worse final postoperative abduction (116° vs. 133°; P = 0.046) and abduction improvement (24° vs. 47°; P = 0.034) compared to OA controls. Both aTSA and rTSA with prior SIS demonstrated significant improvements from baseline across all metrics, with no significant differences between the groups. aTSA and rTSA with prior SIS demonstrated no differences to controls in complications (4.6% vs. 6.1%; P = .786 and 0% vs. 6.3%. P = .183) or revisions (4.6% vs. 4.6%; P = .999 and 0% vs. 4.2%; P = .279). CONCLUSIONS: TSA after prior SIS surgery can improve both pain and function without adversely increasing the rates of complications or revision surgery. When compared to patients without prior SIS, aTSA demonstrated worse abduction; however, all other functional differences remained statistically similar. LEVEL OF EVIDENCE: III; Retrospective Cohort Comparison; Treatment Study.

Reverse shoulder arthroplasty yields similar results to anatomic total shoulder arthroplasty for the treatment of humeral head avascular necrosis.

BACKGROUND: Avascular necrosis (AVN) of the humeral head frequently results in humeral head collapse and end-stage arthritic changes of the glenohumeral joint. Despite the recent proliferation of reverse total shoulder arthroplasty (RTSA), reports on the use of RTSA for AVN remain limited. The purpose of this study was to document the outcomes of shoulders indicated for RTSA in the setting of humeral head AVN and compare these with AVN shoulders indicated for the gold standard, anatomic total shoulder arthroplasty (aTSA). METHODS: A retrospective review of a multinational shoulder arthroplasty database was performed between August 2005 and August 2017. All shoulders with a preoperative diagnosis of AVN (aTSA in 52 and RTSA in 67) were reviewed. The shoulders in the RTSA cohort were matched (1:1) to shoulders with cuff tear arthropathy, whereas the shoulders in the aTSA cohort were matched (1:1) to shoulders with primary osteoarthritis. The mean follow-up period was 47 months (range, 24-130 months) for RTSA and 54 months (range, 24-124 months) for aTSA. Shoulders were evaluated for active range of motion (ROM) and patient-reported outcome measures (PROMs) prior to surgery and at latest follow-up. Patients treated with RTSA were compared with both the aTSA study cohort and the control group using the Student t test or χ2 test as indicated. RESULTS: RTSAs performed for AVN demonstrated significant improvements in all ROMs and PROMs. Patients undergoing aTSA for AVN were significantly younger than those undergoing RTSA (59 years vs. 73 years, P < .001). At similar follow-up points, the RTSA cohort demonstrated significantly greater improvement in abduction (+51° vs. +32°, P = .03) whereas the aTSA cohort demonstrated significantly greater improvement in internal rotation. Postoperative University of California, Los Angeles scores (30 vs. 27, P = .014) and visual analog scale scores (1.4 vs. 2.4, P = .025) were better after RTSA; however, these differences between prosthesis types did not exceed the minimal clinically important difference. When compared with the control patients, the patients undergoing RTSA for AVN showed similar improvements in all ROMs and PROMs. Similarly, aTSA performed for AVN resulted in comparable improvements in pain, ROMs, and PROMs compared with aTSA performed for primary osteoarthritis. CONCLUSION: RTSA results in similar PROMs to aTSA in the treatment of AVN. Therefore, surgeons should continue to consider other patient factors such as glenoid bone loss and rotator cuff status when selecting implant polarity in patients with AVN.

Shoulder arthroplasty is a viable option in patients with Ehlers-Danlos syndrome.

BACKGROUND: Patients with Ehlers-Danlos syndrome (EDS) have high rates of shoulder instability, which place them at increased risk for instability-related arthropathy. Many studies have assessed outcomes for both primary and revision shoulder instability procedures in this patient population, but there is a paucity of data regarding the outcome of shoulder arthroplasty in EDS patients. The purpose of this study is to evaluate the results and complications of shoulder arthroplasty (SA) performed in a cohort of patients with EDS and compare them to a matched cohort of patients with no EDS. METHODS: Over an 11-year period, 10 patients with EDS were identified at a single institution who underwent primary SA (6 anatomic total shoulder arthroplasties [aTSAs], 4 reverse shoulder arthroplasties [RTSAs]). Shoulders were evaluated at a mean follow-up of 60 months (range 25-97 months). This cohort was matched 1:2 based on age, sex, and year of surgery, with patients who underwent SA for either primary osteoarthritis (OA) for aTSA or cuff tear arthropathy for RTSA. EDS patients had a mean age of 55 years, mean body mass index of 26.1, and were all female. The primary outcome measures were postoperative pain, range of motion, complications, and reoperations. RESULTS: SA produced similar postoperative pain, range of motion, complications, and reoperations in patients with EDS vs. controls. EDS patients improved pre- to postoperative visual analog scale (VAS) pain score (6.5 to 1.7, P < .001), elevation (96° to 138°, P = .04), and external rotation (36° to 57°, P = .16). Three EDS patients sustained postoperative complications (2 instability and 1 acromial fracture); however, no shoulder was reoperated. CONCLUSIONS: EDS patients undergoing SA can expect outcomes comparable to patients with primary OA or cuff tear arthropathy, with clinically meaningful improvements in pain and range of motion. Although EDS patients had no statistically significant increase in complications when compared to controls, their absolute rate of overall complications (3/10 patients; 30%) and postoperative instability (2/10 patients; 20%) in this small case series was relatively high and should be considered when performing SA.

Primary reverse shoulder arthroplasty in patients with metabolic syndrome is associated with increased rates of deep infection.

BACKGROUND: Metabolic syndrome (MetS) is an abnormal physiological condition that has been increasingly identified as a risk factor for complications after orthopedic surgery. Given the lack of information on the effect of MetS in shoulder arthroplasty (SA), this investigation analyzed the rates of postoperative complications and implant survivorship free from reoperation and revision in patients with and without MetS. METHODS: Between 2007 and 2017, data from 4635 adults who underwent a primary SA were collected and classified based on the presence or absence of MetS. MetS was defined as the existence of type 2 diabetes mellitus and a minimum of 2 of the following diagnoses: hyperlipidemia, hypertension, and body mass index ≥ 30 kg/m2 within 1 year of surgery. Of the 4635 arthroplasties, 714 were performed in patients with MetS (anatomic total shoulder arthroplasty [aTSA] in 289 and reverse shoulder arthroplasty [RSA] in 425) and 3921 were performed in patients without MetS (aTSA in 1736 and RSA in 2185). Demographic characteristics, complications, reoperations, and revision surgery were compared. RESULTS: At a mean of follow-up of 4.5 ± 2.3 years, 67 MetS patients (9.4%) and 343 non-MetS patients (8.7%) had sustained at least 1 postoperative complication (P = .851). Rotator cuff failure was the most common complication overall, with 84 cases (1.8%) (15 MetS cases [2.1%] and 69 non-MetS cases [1.8%], P = .851), and in both MetS and non-MetS patients, followed by infection, with 68 cases (1.2%) (10 MetS cases [1.4%] and 58 non-MetS cases [1.2%], P = .913). For aTSAs, the most common complication was rotator cuff failure (84 shoulders, 1.8%); for RSAs, the most common complication was periprosthetic fracture (52 shoulders, 1.1%). In RSAs, the rates of deep infection (1.9% vs. 0.7%, P = .04), instability (3.1% vs. 1.5%, P = .04), and deep venous thrombosis or pulmonary embolism (0.5% vs. 0.3%, P = .03) were found to be significantly higher in patients with MetS than in those without MetS. Reoperations were observed in 36 MetS patients (5%) and 170 non-MetS patients (4.3%) (P = .4). Revisions were performed in 30 MetS patients (4.2%) and 127 non-MetS patients (3.2%) (P = .19). The Kaplan-Meier 5-year rate of survivorship free from reoperation, revision, and prosthetic joint infection was equal between groups. CONCLUSIONS: A preoperative diagnosis of MetS in patients undergoing primary SA did not significantly increase the risk of postoperative complications, infection, reoperation, or revision following primary SA. However, in the RSA subgroup, complications were significantly more common in patients with MetS. Individual risk factors may be more appropriate than the umbrella diagnosis of MetS prior to aTSA.

Copper is required for oncogenic BRAF signalling and tumorigenesis.

The BRAF kinase is mutated, typically Val 600→Glu (V600E), to induce an active oncogenic state in a large fraction of melanomas, thyroid cancers, hairy cell leukaemias and, to a smaller extent, a wide spectrum of other cancers. BRAF(V600E) phosphorylates and activates the MEK1 and MEK2 kinases, which in turn phosphorylate and activate the ERK1 and ERK2 kinases, stimulating the mitogen-activated protein kinase (MAPK) pathway to promote cancer. Targeting MEK1/2 is proving to be an important therapeutic strategy, given that a MEK1/2 inhibitor provides a survival advantage in metastatic melanoma, an effect that is increased when administered together with a BRAF(V600E) inhibitor. We previously found that copper (Cu) influx enhances MEK1 phosphorylation of ERK1/2 through a Cu-MEK1 interaction. Here we show decreasing the levels of CTR1 (Cu transporter 1), or mutations in MEK1 that disrupt Cu binding, decreased BRAF(V600E)-driven signalling and tumorigenesis in mice and human cell settings. Conversely, a MEK1-MEK5 chimaera that phosphorylated ERK1/2 independently of Cu or an active ERK2 restored the tumour growth of murine cells lacking Ctr1. Cu chelators used in the treatment of Wilson disease decreased tumour growth of human or murine cells transformed by BRAF(V600E) or engineered to be resistant to BRAF inhibition. Taken together, these results suggest that Cu-chelation therapy could be repurposed to treat cancers containing the BRAF(V600E) mutation.

In Vivo Mechanical Function of the Distal Radial Ulnar Ligaments During Rotation of the Wrist.

PURPOSE: The purpose of this study was to investigate changes in length of the volar and dorsal radioulnar ligaments (VRULs and DRULs), and the distal radioulnar joint (DRUJ) space during unweighted and weighted rotation of the wrist using magnetic resonance imaging and biplanar fluoroscopy. METHODS: Fourteen wrists in 7 normal adult volunteers were imaged to define the 3-dimensional geometry of the DRUJ and the insertion sites of the superficial and deep bundles of the VRULs and DRULs. Subjects were imaged at 10 positions of forearm rotation ranging from full pronation to full supination, with or without a 5-pound weight. Lengths of the superficial and deep VRUL and DRUL bundles and DRUJ space were measured (in millimeters) at each position to evaluate ligament function and DRUJ stability. RESULTS: In the unweighted and weighted trials, maximal elongation of both deep and superficial VRUL bundles occurred in supination and maximal lengths of the deep and superficial DRUL bundles occurred in pronation. Maximum DRUJ space occurred during pronation and a minimum occurred in 30° of supination. In weighted trials, there was a significant increase in deep and superficial VRUL bundle length at positions between 30° of pronation and 30° of supination; however, there was no effect of weight on DRULs length. In weighted trials, there was a significant increase in DRUJ space at positions between full pronation and 15° of supination. CONCLUSIONS: This study demonstrates elongation of the VRULs in supination and the DRULs in pronation. There was no evidence of reciprocal loading of superficial/deep ligament bundles on either the dorsal or the volar aspects of the DRUJ. The effect of loading the wrist during rotation was apparent primarily in the VRULs, but not the DRULs. The DRUJ space was lowest at approximately 30° of supination. CLINICAL RELEVANCE: These results add information to the literature regarding the complicated biomechanics of the triangular fibrocartilage complex and DRUJ. Future work should evaluate changes in biomechanics caused by triangular fibrocartilage complex tears to determine how tear severity and location relate to clinical symptoms.

Robotic-Assisted versus Manual Total Knee Arthroplasty in a Crossover Cohort: What Did Patients Prefer?

BACKGROUND: Robotic-assisted total knee arthroplasty represents an increasingly utilized surgical technology; however, there remains clinical question whether the technique produces improved clinical and patient-reported outcomes. The purpose of this study was to evaluate early clinical outcomes and patient preference of robotic-assisted total knee arthroplasty (rTKA) versus manual TKA (mTKA) in a direct crossover cohort of patients who underwent consecutive TKAs by each technique. MATERIALS AND METHODS: A retrospective chart review and telephone interview was performed on 36 patients who underwent both rTKA and mTKA by a single surgeon between 2012-2018. Perioperative outcomes-complications/reoperations and patient-preferred technique-were collected with mean clinical follow up of 4.8 and 2.0 years for mTKA and rTKA, respectively. RESULTS: mTKA were performed significantly (p<0.01) more quickly than rTKA, including shorter tourniquet time (56 versus 73 minutes) and total operating room time (93 versus 116 minutes). rTKA patients length of stay (LOS) was significantly (p<0.01) decreased (1.8 days) compared to mTKA (2.3 days). For rTKA and mTKA, respectively, there was no difference in final range of motion (119 versus 122 degrees), Visual Analog Scale (1.6 versus 0.9), or Knee Osteoarthritis Outcome Score, Jr (85 versus 87). Twenty (56%) reported rTKA as the preferred technique over mTKA. CONCLUSION: In same patient direct comparison, rTKA required longer operative time but improved LOS compared to mTKA. There was no difference in final outcomes with only slightly more patients preferring rTKA.

Coupling Charge Reduction Mass Spectrometry to Liquid Chromatography for Complex Mixture Analysis.

Electrospray ionization (ESI) of solution mixtures often generates complex mass spectra, even following liquid chromatography (LC), due to analyte multiple charging. Multiple charge state distributions can lead to isobaric interferences, mass spectral congestion, and ambiguous ion identification. As a consequence, data interpretation increases in complexity. Several charge reduction mass spectrometry (MS) approaches have been previously developed to reduce the average charge state of gaseous ions; however, all of these techniques have been restricted to direct infusion MS. In this study, synthetic polyols and surfactants separated by liquid chromatography and ionized by positive mode ESI have been subjected to polonium-210 α-particle radiation to reduce the average charge state to singly charged cations prior to mass analysis. LC/MS analysis of 5000 molecular weight poly(ethylene glycol) (PEG5000) generated an average charge state of 5.88+; whereupon, liquid chromatography/electrospray ionization/charge reduction/mass spectrometry (LC/CR/MS) analysis of PEG 5000 generated an average charge state of 1.00+. The PEG5000 results demonstrated a decrease in spectral complexity and enabled facile interpretation. Other complex solution mixtures representing specific MS challenges (i.e., competitive ionization and isobaric ion overlap) were explored and analyzed with LC/CR/MS to demonstrate the benefits of coupling LC to CR/MS. For example, polyol information related to initiator, identity/relative amount of monomer, and estimated molecular weight was characterized in random and triblock ethylene oxide/propylene oxide polyols using LC/CR/MS. LC/CR/MS is a new analytical technique for the analysis of complex mixtures.

Scapular and Shoulder Girdle Muscular Anatomy: Its Role in Periscapular Tendon Transfers.

The importance of coordinated, normal scapulothoracic motion in facilitating full, pain-free motion of the shoulder complex has been increasingly studied over the past decade, leading to renewed interest in scapular-based reconstructions to improve shoulder girdle motion through the use of muscle advancements and tendon transfers. This article will review recent advances regarding scapulothoracic motion and the muscular stabilizers of the scapula, focusing on clinical diagnosis and anatomy as it pertains to scapular dyskinesis and common periscapular tendon transfers. Although many of these treatment techniques remain in their infancy and further follow-up is necessary before universal adoption, they provide a novel means of addressing difficult-to-treat and complex shoulder girdle pathologies.