Meagan E. Tibbo

Mid-term outcomes of 77 modular radial head prostheses

Aims Radial head arthroplasty (RHA) may be used in the treatment of non‐reconstructable radial head fractures. The aim of this study was to evaluate the mid‐term clinical and radiographic results of RHA. Patients and Methods Between 2002 and 2014, 77 RHAs were implanted in 54 men and 23 women with either acute injuries (54) or with traumatic sequelae (23) of a fracture of the radial head. Four designs of RHA were used, including the Guepar (Small Bone Innovations (SBi)/Stryker; 36), Evolutive (Aston Medical; 24), rHead RECON (SBi/Stryker; ten) or rHead STANDARD (SBi/ Stryker; 7) prostheses. The mean follow‐up was 74.0 months (standard deviation (SD) 38.6; 24 to 141). The indication for further surgery, range of movement, mean Mayo Elbow Performance (MEP) score, quick Disabilities of the Arm, Shoulder and Hand (quickDASH) score, osteolysis and positioning of the implant were also assessed according to the design, and acute or delayed use. Results The mean MEP and quickDASH scores were 90.2 (SD 14; 45 to 100), and 14.0 points (SD 12; 1.2 to 52.5), respectively. There were no significant differences between RHA performed in acute or delayed fashion. There were 30 re‐operations (19 with, and 11 without removal of the implant) during the first three post‐operative years. Painful loosening was the primary indication for removal in 14 patients. Short‐stemmed prostheses (16 mm to 22 mm in length) were also associated with an increased risk of painful loosening (odds ratio 3.54 (1.02 to 12.2), p = 0.045). Radiocapitellar instability was the primary indication for reoperation with retention of the implant (5). The overall survival of the RHA, free from reoperation, was 60.8% (SD 5.7%) at ten years. Conclusion Bipolar and press‐fit RHA gives unsatisfactory mid‐term outcomes in the treatment of acute fractures of the radial head or their sequelae. The outcome may vary according to the design of the implant. The rate of re‐operation during the first three years is predictive of the longterm survival in tight‐fitting RHAs.

The minimum follow-up required for radial head arthroplasty: a meta-analysis

Aims The primary aim of this study was to define the standard minimum follow‐up required to produce a reliable estimate of the rate of re‐operation after radial head arthroplasty (RHA). The secondary objective was to define the leading reasons for re‐operation. Materials and Methods Four electronic databases, between January 2000 and March 2017 were searched. Articles reporting reasons for re‐operation (Group I) and results (Group II) after RHA were included. In Group I, a meta‐analysis was performed to obtain the standard minimum follow‐up, the mean time to re‐operation and the reason for failure. In Group II, the minimum follow‐up for each study was compared with the standard minimum follow‐up. Results A total of 40 studies were analysed: three were Group I and included 80 implants and 37 were Group II and included 1192 implants. In Group I, the mean time to re‐operation was 1.37 years (0 to 11.25), the standard minimum follow‐up was 3.25 years; painful loosening was the main indication for re‐operation. In Group II, 33 Group II articles (89.2%) reported a minimum follow‐up of < 3.25 years. Conclusion The literature does not provide a reliable estimate of the rate of re‐operation after RHA. The reproducibility of results would be improved by using a minimum follow‐up of three years combined with a consensus of the definition of the reasons for failure after RHA. Cite this article: Bone Joint J 2017;99‐B:1561‐70.

A randomized controlled trial of fixed- versus mobile-bearing total knee arthroplasty

Aims It has been suggested that mobile‐bearing total knee arthroplasty (TKA) might lead to better outcomes by accommodating some femorotibial rotational mismatch, thereby reducing contact stresses and polyethylene wear. The aim of this study was to determine whether there is a difference between fixed‐ and mobile‐bearing versions of a contemporary TKA with respect to durability, range of movement (ROM) and function, ten years postoperatively. Patients and Methods A total of 240 patients who were enrolled in this randomized controlled trial (RCT) underwent a primary cemented TKA with one of three tibial components (all‐polyethylene fixed‐bearing, modular metal‐backed fixed‐bearing and mobile‐bearing). Patients were reviewed at a median follow‐up of ten years (IQR 9.2 to 10.4). Results There was no difference in durability, as measured by survivorship free of revision for any reason, nor in mean maximal ROM at ten years (p = 0.8). There was also no difference in function, as measured by Knee Society (KS) function scores (p = 0.63) or the prevalence of patellar tilt (p = 0.12). Conclusion In this clinical RCT, the mobile‐bearing design of TKA was found to be reliable and durable, but did not provide better maximum knee flexion, function or durability ten years postoperatively compared with a posterior‐stabilized, fixed‐bearing design incorporating either an all‐polyethylene or a modular‐metal‐backed tibial component.

Primary Total Hip Arthroplasty for Charcot Arthropathy is Associated With High Complications but Improved Clinical Outcomes

BACKGROUND Neuropathic (Charcot) arthropathy of the hip is rare but can lead to joint destruction, bone loss, and dysfunction. While total hip arthroplasty (THA) may be considered a treatment option, only very limited data in the form of case reports are available on the results of THA. The goal of this study was to analyze the outcomes of primary THA for Charcot arthropathy with emphasis on implant survivorship, complications, and clinical outcomes. METHODS Eleven patients undergoing 12 primary THAs for Charcot arthropathy from 2007 to 2014 were retrospectively reviewed. All patients had a severe underlying neuropathy and clear radiographic evidence of Charcot arthropathy. Mean age was 54 years with 4 patients being female. Mean follow-up was 5 years. RESULTS Survivorship free of any revision was 75% at both 2 and 5 years. Three THAs (3/12) were revised: 2 for recurrent instability and 1 for femoral component loosening. Survivorship free of any reoperation was 67% at both 2 and 5 years. One additional THA underwent open reduction and internal fixation of a Vancouver B1 periprosthetic fracture. The overall complication rate (including revisions and reoperations) was high at 58% with 3 recurrent dislocations, 2 periprosthetic fractures, 1 femoral component loosening, and 1 delayed wound healing. Harris Hip Scores improved from a mean of 43 preoperatively to 81 postoperatively (P < .001). CONCLUSION In this study, the largest to date, we found that patients undergoing primary THA for Charcot arthropathy have a significant improvement in clinical outcomes but that there was a high risk of early complications and revisions, mostly related to recurrent instability. Specific precautions to avoid early complications, namely utilization of components that provide robust fixation and strategies that provide enhanced hip stability, should be considered. LEVEL OF EVIDENCE Level IV.

Molecular pathology of total knee arthroplasty instability defined by RNA-seq

Total knee arthroplasty (TKA) is a durable and reliable procedure to alleviate pain and improve joint function. However, failures related to flexion instability sometimes occur. The goal of this study was to define biological differences between tissues from patients with and without flexion instability of the knee after TKA. Human knee joint capsule tissues were collected at the time of primary or revision TKAs and analyzed by RT-qPCR and RNA-seq, revealing novel patterns of differential gene expression between the two groups. Interestingly, genes related to collagen production and extracellular matrix (ECM) degradation were higher in samples from patients with flexion instability. Partitioned clustering analyses further emphasized differential gene expression patterns between sample types that may help guide clinical interpretations of this complication. Future efforts to disentangle the effects of physical and biological (e.g., transcriptomic modifications) risk factors will aid in further characterizing and avoiding flexion instability after TKA.

Joint contracture is reduced by intra-articular implantation of rosiglitazone-loaded hydrogels in a rabbit model of arthrofibrosis: ROSIGLITAZONE-LOADED HYDROGELS IN A RABBIT MODEL OF ARTHROFIBROSIS

Trauma, surgery, and other inflammatory conditions can lead to debilitating joint contractures. Adjunct pharmacologic modalities may permit clinical prevention and treatment of recalcitrant joint contractures. We investigated the therapeutic potential of rosiglitazone by intra‐articular delivery via oligo[poly(ethylene glycol)fumarate] (OPF) hydrogels in an established rabbit model of arthrofibrosis. OPF hydrogels loaded with rosiglitazone were characterized for drug elution properties upon soaking in minimum essential media (MEM) with 10% fetal bovine serum and measurements of drug concentrations via High Performance Liquid Chromatography (HPLC). Drug‐loaded scaffolds were surgically implanted into 24 skeletally mature female New Zealand White rabbits that were divided into equal groups receiving OPF hydrogels loaded with rosiglitazone (1.67 mg), or vehicle control (10 µl DMSO). After 8 weeks of joint immobilization, rabbits were allowed unrestricted cage activity for 16 weeks. Contracture angles of rabbit limbs treated with rosiglitazone showed statistically significant improvements in flexion compared to control animals (mean angles, respectively, 64.4° vs. 53.3°, p < 0.03). At time of sacrifice (week 24), animals in the rosiglitazone group continued to exhibit less joint contracture than controls (119.0° vs. 99.5°, p = 0.014). The intra‐articular delivery of rosiglitazone using implanted OPF hydrogels decreases flexion contractures in a rabbit model of arthrofibrosis without causing adverse effects (e.g., gross inflammation or arthritis). Statement of Clinical Significance: Post‐traumatic joint contractures are common and debilitating, with limited available treatment options. Pharmacologic interventions can potentially prevent and treat such contractures. This study is translational in that a commercially approved medication has been repurposed through a novel delivery device.

Degenerative subtalar joints complicated by medial plantar intraneural cysts: cutting the cystic articular branch prevents recurrence

Aims The pathogenesis of intraneural ganglion cysts is controversial. Recent reports in the literature described medial plantar intraneural ganglion cysts (mIGC) with articular branches to subtalar joints. The aim of the current study was to provide further support for the principles underlying the articular theory, and to explain the successes and failures of treatment of mICGs. Patients and Methods Between 2006 and 2017, five patients with five mICGs were retrospectively reviewed. There were five men with a mean age of 50.2 years (33 to 68) and a mean follow‐up of 3.8 years (0.8 to 6). Case history, physical examination, imaging, and intraoperative findings were reviewed. The outcomes of interest were ultrasound and/or MRI features of mICG, as well as the clinical outcomes. Results The five intraneural cysts followed the principles of the unifying articular theory. Connection to the posterior subtalar joint (pSTJ) was identified or suspected in four patients. Reevaluation of preoperative MRI demonstrated a degenerative pSTJ and denervation changes in the abductor hallucis in all patients. Cyst excision with resection of the articular branch (four), cyst incision and drainage (one), and percutaneous aspiration/steroid injection (two) were performed. Removing the connection to the pSTJ prevented recurrence of mIGC, whereas medial plantar nerves remained cystic and symptomatic when resection of the communicating articular branch was not performed. Conclusion Our findings support a standardized treatment algorithm for mIGC in the presence of degenerative disease at the pSTJ. By understanding the pathoanatomic mechanism for every cyst, we can improve treatment that must address the articular branch to avoid the recurrence of intraneural ganglion cysts, as well as the degenerative pSTJ to avoid extraneural cyst formation or recurrence.

Primary Total Knee Arthroplasty in Patients With Neuropathic (Charcot) Arthropathy: Contemporary Results

BACKGROUND Total knee arthroplasty (TKA) for neuropathic (Charcot) arthropathy is technically challenging with higher complication rates than primary TKA for osteoarthritis. There is a paucity of data regarding outcomes of TKA in contemporary cohorts with modern implants, techniques, and indications. Our study aimed to determine the (1) survivorship of implants, (2) rates and types of complications, (3) clinical outcomes, and (4) radiographic outcomes in patients treated with primary TKA for Charcot arthropathy. METHODS Twenty-seven patients undergoing 37 TKAs for Charcot arthropathy from 2000 to 2015 were retrospectively reviewed. Mean patient age and follow-up were 60 years and 6 years, respectively. Eighty-one percent were treated with either a varus-valgus constrained or rotating-hinge device, and 81% had supplemental stem fixation. Metaphyseal cones were utilized in 19% of cases. RESULTS The 10-year survivorship free of aseptic revision was 88% and free of any revision was 70%. There were 6 revisions (16%): 4 for infection, 1 for tibial component loosening, and 1 for global instability. There were 3 reoperations (8%). Additional complications occurred in 6 patients (16%) including 3 patients with an intraoperative fracture. Mean Knee Society scores improved from 37 preoperatively to 82 postoperatively (P < .001). There was no radiographic evidence of component loosening in any unrevised knee at latest follow-up. CONCLUSIONS Primary TKA for Charcot arthropathy with selective use of increased constraint and enhanced metaphyseal component fixation led to significant improvement in pain and clinical outcomes when compared with older techniques; however, there was a high perioperative complication rate. While 10-year survivorship free of aseptic revision was 88%, periprosthetic joint infection led to the poorer survivorship free of any revision of 70% at 10 years. LEVEL OF EVIDENCE Level IV.

Molecular pathology of adverse local tissue reaction caused by metal-on-metal implants defined by RNA-seq.

Total hip arthroplasty (THA) alleviates hip pain and improves joint function. Current implant design permits long-term survivorship of THAs, but certain metal-on-metal (MoM) articulations can portend catastrophic failure due to adverse local tissue reactions (ALTR). Here, we identified biological and molecular differences between periacetabular synovial tissues of patients with MoM THA failure undergoing revision THA compared to patients undergoing primary THA for routine osteoarthritis (OA). Analysis of tissue biopsies by RNA-sequencing (RNA-seq) revealed that MoM patient samples exhibit significantly increased expression of immune response genes but decreased expression of genes related to extracellular matrix (ECM) remodeling. Thus, interplay between local tissue inflammation and ECM degradation may account for the pathology and compromised clinical outcomes in select patients with MoM implants. We conclude that adverse responses of host tissues to implant materials result in transcriptomic modifications in patients with MoM implants that permit consideration of strategies that could mitigate ECM damage.

Ultrasound-guided proximal suprascapular nerve block: A cadaveric study: Proximal Suprascapular Nerve Block

Difficulty in identifying the susprascapular nerve (SSN) limits the success of US‐guided regional anesthetic injections. A proximal SSN block could be an effective and reliable approach. The primary objective was to validate the feasibility of the US‐guided proximal SSN block. The secondary objective was to quantify the spread of the colored local anesthetic to the phrenic nerve (PN). Fourteen brachial plexuses from seven cadavers were included. Characterization of the proximal SSN was performed using US to determine the diameter and depth of the origin of the SSN (orSSN). Ten mL of methylene blue‐infused ropivacaine 0.2% were then injected to the proximal portion of the SSN. After dissection, the distances between the tip of the needle and the orSSN and the PN were anatomically determined. The PN was also judged to be colored or not by the methylene blue. The mean diameter and depth of the orSSN were 0.2 cm (range, 0.1‐0.3 cm) and 1.5 cm (range, 0.6‐2 cm) respectively. The orSSN was successfully targeted in 14 of 14 specimens with US; the tip of the needle was a mean of 1.6 cm (range, 0.2‐2.5 cm) and 5.1 cm (range, 4‐6.5 cm) from the orSSN and PN respectively. The orSSN and PN were marked in 14 and 3 cases respectively. US‐guided proximal SSN block is effective and reliable. The origin of the SSN is an easily identifiable landmark. This regional anesthesia could also reduce the risk of phrenic nerve palsy following interscalene brachial plexus block. Clin. Anat. 31:824–829, 2018.