Decision-making in the treatment of radial head fractures: Delphi methodology.

BACKGROUND: The treatment of partially displaced radial head fractures is determined not only by the type of fracture but also by patient characteristics such as age, occupation, hand dominance, mechanism of injury, and concomitant injuries and comorbidities. The goal of this study was to employ the Delphi method to achieve consensus on the management of patients with radial head fractures, utilizing the experience of the ASES Elbow Fracture-Dislocation Multicenter Study Group and Mayo Elbow Club surgeons. METHODS: The initial survey was sent to participants, which included consent to participate in the study and questions about their experience, knowledge, and interest in participating in the Delphi method. We used both open-ended and category-based questions. The second questionnaire generated 76 variables, and individual questions with mean Likert ratings of <2.0 or >4.0 were deemed significant and merged to form multifactorial clinical scenarios relating to both nonoperative and operative management, respectively. RESULTS: Of the surgeons who responded to the questionnaire, 64% were from the United States, while the remainder were from overseas practices. Years in practice on average were 12.4 years (range, 1-40). Seven of the 76 factors met the criteria of a mean Likert score of <2.0 or >4.0. These factors were as follows: age, block to the range of motion (ROM) after aspiration/injection, crepitation with ROM, tenderness over the distal radioulnar joint and/or interosseous membrane (dorsal forearm), gap and/or displacement >2 mm on imaging, complete loss of contact of the head with the rest of the radius on imaging, and fracture head involvement 30% on imaging. Twenty-two (46%) of the 96 clinical scenarios gained >90% consensus in favor of surgical treatment, whereas 8 (17%) reached >90% consensus in favor of nonoperative treatment. CONCLUSION: Obtaining expert consensus on the treatment of radial head fractures remains challenging. Certain factors such as gap/displacement ≥2 mm without complete loss of contact, ≥30% head involvement with a block to an ROM regardless of tenderness over distal radioulnar joint or interosseous membrane (dorsal forearm), or crepitation when the patient was <80 years of age led to a recommendation of operative treatment in 100% of the surveyed surgeons. Patients older than 80 years with no block to ROM after aspiration/injection, no crepitation with ROM, and no tenderness on distal radioulnar joint/interosseous membrane (dorsal forearm) were recommended for nonoperative treatment regardless of the size of the radial head involvement on imaging.

Safety of Arthroscopic Versus Open or Combined Heterotopic Ossification Removal Around the Elbow.

PURPOSE: To analyze the complications of arthroscopic heterotopic ossification (HO) excision and compare them with those of open removal of HO or a combined open-arthroscopic approach. METHODS: We performed a retrospective review of elbow HO removal cases performed by a single surgeon from 1997 to 2014. In all cases studied, the intention was to restore range of motion owing to the presence of HO causing functional impairment. The arthroscopic, open, and combined treatment groups were compared. RESULTS: The study cohort consisted of 223 surgical procedures performed on 213 elbows in 211 patients. Fifty major complications occurred in 46 cases (21%): 17 hematomas (8%) treated by irrigation and debridement, 8 cases of HO requiring reoperation (4%), 7 deep infections (3%), 4 contractures (2%), 3 cases of delayed-onset ulnar neuritis (1%), 2 cases of distal humeral avascular necrosis (1%), 2 tendon ruptures (1%), 2 cases of instability requiring reconstruction (1%), 2 postoperative fractures (1%), 1 intraoperative fracture (<0.5%), 1 case of worsening of pre-existing neuropathic pain (<0.5%), and 1 permanent partial posterior interosseous nerve injury (<0.5%). Of these 46 cases, the major complications occurred in 6 of the 41 (15%) performed arthroscopically, in 36 of the 158 (23%) performed open and in 4 of the 21 (17%) with combined (i.e. open + arthroscopic) HO removal. Preventive strategies, introduced to prevent hematomas and delayed-onset ulnar neuritis, reduced the rate of major complications from 35% during the period from 1997 to 2005 to 10% during the period from 2006 to 2014 (P < .0001). Moreover, the rate of reoperations was reduced from 34% to 10% in the same periods (P < .0001). Minor complications occurred in 36 cases (16%), including 17 cases of transient nerve palsy, 9 cases of superficial infection or delayed wound healing, 6 cases of mild instability, and 4 cases of hematoma resolved by aspiration. CONCLUSIONS: The use of arthroscopy-or a combination of arthroscopic and open techniques-to remove HO around the elbow by a surgeon skilled in both arthroscopic and open elbow surgery does not increase the risk of major complications or need for reoperation compared with traditional open surgery. Preventive strategies, such as avoiding raising skin flaps by using multiple separate incisions for open and prophylactic ulnar nerve decompression in arthroscopic cases, were developed during the study period. These strategies were monitored prospectively and found to be effective in preventing two-thirds of the major complications needing reoperation with both open and arthroscopic HO removal. LEVEL OF EVIDENCE: Level III, retrospective comparative study of prospectively collected data.

Posteromedial rotatory incongruity of the elbow: a computational kinematics study.

BACKGROUND: Our objective was to analyze the effect of different anteromedial coronoid fracture patterns with different combinations of ligamentous repairs. We hypothesized that smaller fractures would be sufficiently treated with ligamentous repair alone but that larger fragments would require a combination of ligament and bony repair versus reconstruction. METHODS: Two multibody models were created from cadaveric specimens in the ADAMS program. Four different conditions were simulated: (1) no fracture, (2) O'Driscoll anteromedial subtype I (2.5-mm) fracture, (3) subtype II 2.5-mm fracture, and (4) subtype II 5-mm fracture. In each of these conditions, 3 ligament repairs were studied: lateral ulnar collateral ligament (LUCL), posterior bundle of the medial collateral ligament (pMCL), and both LUCL and pMCL. For each condition, kinematics and articular contact areas were calculated. RESULTS: LUCL repair alone increases whereas pMCL repair decreases internal rotation of the ulna relative to all tested posteromedial rotatory instability conditions; their rotational effects are summative when both ligaments are repaired. With a subtype I fracture and both pMCL and LUCL injuries, repairing the LUCL alone corrects angulation whereas rotational stability is satisfactory through the arc from 0° to 90°. In a subtype II 2.5-mm fracture, isolated repair of the LUCL or pMCL is not capable of restoring rotation or angulation. For a subtype II 5-mm fracture, no combination of ligamentous repairs could restore rotation or angulation. CONCLUSIONS: This study suggests that LUCL repair alone is sufficient to restore kinematics for small subtype I fractures for an arc avoiding deep flexion; whereas nearly normal kinematics throughout the arc of motion can be achieved if the pMCL is also repaired. Larger anteromedial coronoid fractures should ideally have fragments fixed in addition to ligament repairs.

Loss of pronation-supination in patients with heterotopic ossification around the elbow.

BACKGROUND: Heterotopic ossification (HO) is a well-recognized cause of limited flexion-extension, but it can also limit pronation-supination. There is a paucity of literature concerning restriction of pronation-supination due to HO. METHODS: We conducted a retrospective review of patients who had undergone elbow surgery for HO removal between January 1, 2003, and September 27, 2013. Computed tomography scans were reviewed to determine the presence of HO restricting forearm rotation and were rated independently by 4 observers. Each elbow was given 1 of 4 scores according to the likelihood that HO was restricting forearm rotation. Agreement was achieved when 3 or 4 observers thought that HO definitely or probably caused a loss of pronation-supination. RESULTS: Of 132 post-traumatic patients undergoing HO excision for restricted elbow motion, 61 (46%) also lacked a functional arc of pronation and supination (50° and 50°, respectively). Of these 61 patients, 32 (53%) were considered to have lost forearm rotation because of HO. The remaining 29 patients (47%) were thought to have restricted forearm rotation for reasons unrelated to HO. DISCUSSION: In this study, loss of pronation-supination affected almost half of the patients (61 of 132 [46%]) undergoing HO excision around the elbow. Of these 61 patients, 32 (52%) had HO extending into the proximal forearm and affecting rotation. From our data, one can expect that about one-quarter (24% of patients in this study, or 32 of 132) with post-traumatic HO of the elbow will have a significant functional loss of pronation-supination due to HO extending into the forearm.

Effects of axial forearm instability on force transmission across the elbow.

BACKGROUND: The interosseous membrane (IOM) and distal radioulnar joint (DRUJ) provide axial stability to the forearm. Our hypothesis was that injury to these structures alters force transmission through the elbow. METHODS: A custom-designed apparatus that applies axial loads from the wrist to the elbow was used to test 10 cadaveric upper limbs under the following simulated conditions (1) intact, (2) DRUJ injury, (3) IOM injury, or (4) IOM + DRUJ injury. IOM injury was simulated by osteotomies of the IOM attachment to the radius, and DRUJ injury was simulated by distal ulnar oblique osteotomy. We applied 160 N of axial force during cyclic and functional range of forearm rotation (40o pronation/40o supination), and force, contact pressure, and contact area through the elbow joint were measured simultaneously. RESULTS: The force across the radiocapitellar joint was significantly higher in the IOM + DRUJ injury and the IOM injury groups than in the intact and DRUJ injury groups. The mean force across the radiocapitellar joint was not significantly different between the intact and DRUJ injury groups or between the IOM + DRUJ injury and the IOM injury groups. Forces across the ulnohumeral joint showed an inverse pattern to those in the radiocapitellar joint. CONCLUSIONS: These findings suggest that injury to the IOM contributes more to the disruption of the normal distribution of axial loads across the elbow than injury to the DRUJ.

Axial load transmission through the elbow during forearm rotation.

BACKGROUND: Forearm rotation is closely associated with the axiorotational force transmission through the elbow joint. A technique has been developed to study the transmission of force across the radiocapitellar and ulnotrochlear joints during forearm rotation. METHODS: Ten human cadaveric upper limbs were prepared on a custom-designed apparatus that permits the application of extrinsic axial loads across an intact cadaveric elbow joint. A force-sensitive transducer was inserted into the elbow joint of each cadaver. A 160 N axial force was applied to the specimen during cyclic forearm rotation while the force, contact pressure, and contact area through the elbow joint were measured. RESULTS: The mean force across the radiocapitellar joint showed no significant difference between pronation and supination (P = .3547). The radiocapitellar joint showed significantly higher contact area (P = .0001) and lower contact pressure (P = .0001) in pronation than in supination. The mean values for contact pressure, area, and force across the ulnotrochlear joint were not significantly different between supination and pronation. CONCLUSION: The contact pressure and contact area of the radiocapitellar joint in the cadaveric model changed according to forearm rotation while the force remained constant. The mean contact pressure of the radiocapitellar joint in pronation was significantly lower than that in supination because the force across it did not change significantly and its contact area decreased significantly. These findings may suggest that the pronated elbow can play an important role in protecting the radiocapitellar joint in high-impact activities like delivering punch in martial arts or falling on an outstretched arm.

Role of the lateral collateral ligament in posteromedial rotatory instability of the elbow.

BACKGROUND: Posteromedial rotatory instability (PMRI) of the elbow consists of an anteromedial coronoid fracture with lateral collateral ligament (LCL) and posterior bundle of the medial collateral ligament (PMCL) tears. We hypothesized that the LCL tear is required for elbow subluxation/joint incongruity and that an elbow affected by an anteromedial subtype 2 coronoid fracture and a PMCL tear exhibits contact pressures different from both an intact elbow and an elbow affected by PMRI. MATERIALS AND METHODS: Six cadaveric elbows were tested under gravity varus stress using a custom-made machine designed to simulate muscle loads and to passively flex the elbow from 0° to 90° and measure joint contact pressures. After testing of the intact specimen (INTACT-elbow), an anteromedial subtype 2 coronoid fracture with a PMCL tear (COR+PMCL-elbow) and a PMRI injury (PMRI-elbow), after adding an LCL tear, were tested. The highest values of mean contact pressure were used for the comparison among the 3 groups. RESULTS: Neither subluxation nor joint incongruity was observed in the COR+PMCL-elbow. The addition of an LCL detachment consistently caused subluxation and joint incongruity. Mean contact pressures were higher in the COR+PMCL-elbow compared with the INTACT-elbow (P < .03) but lower than in the PMRI-elbow (P < .001). CONCLUSIONS: The LCL lesion in PMRI is necessary for elbow subluxation and causes marked elevations in contact pressures. Even without subluxation, the COR+PMCL-elbow showed higher contact pressures compared with the INTACT-elbow. Treatment of PMRI should be directed toward prevention of joint incongruity, whether by surgical or nonsurgical means, to prevent high articular contact pressures.

Coronoid reconstruction using osteochondral grafts: a biomechanical study.

HYPOTHESIS: The purposes of this study were to test the hypothesis that coronoid deficiency in the setting of posteromedial rotatory instability (PMRI) must be reconstructed to restore articular contact pressures to normal and to compare 3 different osteochondral grafts for this purpose. METHODS: After creation of a anteromedial fracture, six cadaveric elbows were tested under gravity varus stress using a custom-made machine designed to simulate muscle loads and to passively flex the elbow. Mean articular surface contact pressure data were collected and processed using TekScan sensors and software. After testing of the intact specimen (intact condition), a PMRI injury was created (PMRI condition). Testing was repeated after reconstruction of the lateral collateral ligament (LCL) (LCL-only condition), followed by reconstruction of the coronoid with 3 different osteochondral graft techniques (reconstructed conditions). RESULTS: Contact pressure was consistently significantly higher in the PMRI elbow compared with the intact, LCL-only, and reconstructed conditions (P < .006). The LCL-only elbow contact pressure was significantly higher than that of the intact and reconstructed conditions from 5° to 55° of flexion (P = .018). The contact pressure of the intact elbow was never significantly different from that of the reconstructed elbow, except at 5° of flexion (P ≤ .008). No significant difference was detected between each of the reconstructed techniques (P ≥ .15). However, the annular surface of the radial head was the only graft that yielded contact pressures not significantly different from normal at any flexion angle. CONCLUSION: Isolated reconstruction of the LCL did not restore native articular surface contact pressure, and reconstruction of the coronoid using osteochondral graft was necessary. There was no difference in contact pressures among the 3 coronoid reconstruction techniques.

The Safety of Using Proximal Anteromedial Portals in Elbow Arthroscopy With Prior Ulnar Nerve Transposition.

PURPOSE: To report the safety of using the proximal anteromedial portal, using a simplified ulnar nerve management strategy derived from an earlier study, in a series of patients with previously transposed ulnar nerves. METHODS: A retrospective review of all elbow arthroscopies performed by a single surgeon from 2009 to 2014 was performed. The following techniques were used if, by palpation, localization of the ulnar nerve was considered to be certain (group 1) or uncertain (group 2): In group 1 (certain) the proximal anteromedial portal was established in the normal antegrade fashion. In group 2 (uncertain) a 1- to 3-cm incision was made at the planned proximal anteromedial portal site, and blunt dissection down to the capsule was performed without identification of the nerve. The nerve was not visualized but sometimes was palpated through the wound to confirm its location anteriorly or posteriorly. If there was a disparity between the prior operative records and the physical examination findings, the nerve was explored through a 3- to 4-cm incision. RESULTS: We reviewed 394 elbow arthroscopy cases, 22 of which had a prior transposed ulnar nerve (21 subcutaneous and 1 submuscular) that required anterior-compartment arthroscopic surgery. Group 1 (certain location) consisted of 9 elbows (41%), whereas group 2 (uncertain location) consisted of 13 (59%). In 2 cases in group 2, the ulnar nerve was explored because of the disparity between the previous medical records and the physical examination findings. There were no operative ulnar nerve injuries related to the use of the proximal anteromedial portal. CONCLUSIONS: The proximal anteromedial portal was able to be used safely in patients with prior transposition of the ulnar nerve. This was achieved by using an algorithm based on the degree of certainty with which the nerve can be localized in the region of the planned portal by clinical palpation. LEVEL OF EVIDENCE: Level IV, therapeutic case series.

Negative coupling and coupling phase dispersion in a silicon quadrupole micro-racetrack resonator.

We report the first experimental study of the effects of coupling phase dispersion on the spectral response of a two-dimensionally coupled quadrupole micro-racetrack resonator. Negative coupling in the system is observed to manifest itself in the sharp stop band transition and deep extinction in the pseudo-elliptic filter response of the quadrupole. The results demonstrate the feasibility of realizing advanced silicon microring devices based on the 2D coupling topology with general complex coupling coefficients.

The effect of prosthetic radial head geometry on the distribution and magnitude of radiocapitellar joint contact pressures.

PURPOSE: To determine if radiocapitellar contact pressures would be elevated with nonanatomical (circular) prostheses over those mimicking native anatomy and if such pressures would be related to the depth and contour of the articular dish and to the pattern of prosthetic articulation against the lateral trochlear ridge. METHODS: Three commercially available circular radial head designs were compared with an anatomical radial head and 2 modified anatomical prototype radial head designs in 10 cadaveric specimens. Each prosthesis and specimen combination was loaded in neutral rotation and maximal extension with a custom testing apparatus while measuring contact areas and pressures using thin-film pressure sensors. RESULTS: Anatomical radial head prototype 2 had similar radiocapitellar contact areas and mean pressures as the native radial head; all other designs showed significant decreases in contact area and increased mean pressures. Peak contact pressures were also measured and were significantly elevated with all prostheses tested. Anatomical designs are statistically more likely to mimic normal contact with the lateral trochlear ridge and its adjacent sulcus than circular prostheses. They are also significantly less likely to have contact pressures above the 5 MPa threshold that is thought to be harmful to cartilage. The depth of the articular dish had a significant effect on contact area and pressure. CONCLUSIONS: Commercially available radial head prostheses demonstrated reduced radiocapitellar contact areas and elevated contact pressures during compressive loading. These were significantly greater with symmetrical circular prostheses than with asymmetrical elliptical designs. The prosthesis that best mimicked native contact behavior was the anatomical radial head prototype 2 owing to its design for articulating with the capitellum, the lateral trochlear ridge, and the sulcus between. CLINICAL RELEVANCE: Because radial head prostheses have the potential to cause capitellar erosion or arthritic change, those with lower contact pressures may lead to fewer such complications.

Preoperative nerve imaging using computed tomography in patients with heterotopic ossification of the elbow.

HYPOTHESIS: This study evaluated the usefulness of computed tomography (CT) imaging for preoperative planning of heterotopic ossification (HO) excision, specifically the spatial relationship between HO and radial and median nerves. Our hypotheses were that CT imaging of the elbow can be used (1) to trace the paths of the radial and median nerves, (2) to distinguish the nerves from the heterotopic bone, and (3) to precisely measure distances from the respective nerve to the most clinically relevant HO. MATERIALS AND METHODS: Patients who had HO removed from the elbow were reviewed retrospectively. On the basis of preoperative CT scans, 22 were identified as likely having HO along the pathway of the radial or median nerve. These cases were independently evaluated by 4 observers, who answered these questions: (1) Can the location of the nerve be adequately seen on sequential images to permit tracing of its path for surgical planning? (2) Can the nerve be distinguished from the HO accurately enough to permit measurement of its distance from the bone? Each observer also measured the shortest distance between nerves and the HO. RESULTS: Overall utility of the CT images for visualizing the nerves was high. The radial nerve was more readily distinguished from the HO (21 of 22 cases) than the median nerve (17 of 22 cases). The distance measured from HO was less for the radial nerve (3 mm) than for the median nerve (9 mm). CONCLUSION: This study demonstrates the usefulness of CT imaging to determine the paths of the radial and median nerves and their spatial relationship to HO at the elbow.

MPFL Reconstruction and Implant-Mediated Guided Growth in Skeletally Immature Patients With Patellar Instability and Genu Valgum.

BACKGROUND: There is a higher rate of failure of isolated MPFL reconstruction in skeletally immature patients with patellar instability compared to skeletally mature patients. Genu valgum is a known risk factor for patellar instability. There is potential for concomitant surgical correction of genu valgum to achieve better clinical outcomes and to decrease failure rates of MPFL reconstruction. PURPOSE: To evaluate outcomes of combined medial patellofemoral ligament (MPFL) reconstruction and implant-mediated guided growth (IMGG) in skeletally immature patients with patellar instability and genu valgum. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: In a multicenter study, all skeletally immature patients with recurrent patellar instability and genu valgum who underwent MPFL reconstruction using hamstring graft and IMGG using a transphyseal screw or tension band plate for the distal femur and/or proximal tibia were included. The knee valgus angle and mechanical axis were measured on full-length radiographs and anatomic risk factors were measured on MRI. Patients were followed until correction of their lower limb alignment and implant removal or until skeletal maturity. Clinical outcomes, including complications, were analyzed. RESULTS: A total of 31 patients (37 knees) were included in the study. The mean age and skeletal age of the cohort were 12.4 and 12.9 years, respectively. Simultaneous MPFL reconstruction and IMGG were performed in 26 of 37 knees; 11 underwent staged procedures. Twenty knees had transphyseal screws and 17 knees had tension band plates for IMGG. The knee valgus corrected from a mean of 12.4° to 5.1° in 12.1 months. Implants were removed from 22 of 37 knees once genu valgum was corrected. There was no significant difference (P = .65) in the correction rate between plates (0.7 deg/month) and screws (0.6 deg/month). Ten complications occurred in 4 patients (7 knees) and included 5 patellar redislocations, 2 rebound valgus, 1 varus overcorrection, 1 knee arthrofibrosis, and 1 implant loosening. For children <10 years of age, 3 of 6 (50%) knees had patellar redislocations and 5 of 6 knees had a complication. This was statistically significant (P = .003) compared with patients >10 years of age. Similarly, for patients with bilateral knee involvement, 5 of 12 (42%) knees had patellar redislocations and a total of 8 complications occurred in this subset. This was statistically significant (P < .001) compared with patients with unilateral involvement. CONCLUSION: IMGG with plates or screws in the setting of combined MPFL reconstruction improves genu valgum. Children <10 years of age and those with bilateral instability with genu valgum remain difficult subsets to treat with higher complication rates.

Permanent fine tuning of silicon microring devices by femtosecond laser surface amorphization and ablation.

We demonstrate the fine tuning capability of femtosecond laser surface modification as a permanent trimming mechanism for silicon photonic components. Silicon microring resonators with a 15 µm radius were irradiated with single 400 nm wavelength laser pulses at varying fluences. Below the laser ablation threshold, surface amorphization of the crystalline silicon waveguides yielded a tuning rate of 20 ± 2 nm/J · cm(-2)with a minimum resonance wavelength shift of 0.10nm. Above that threshold, ablation yielded a minimum resonance shift of -1.7 nm. There was some increase in waveguide loss for both trimming mechanisms. We also demonstrated the application of the method by using it to permanently correct the resonance mismatch of a second-order microring filter.

Photothermal nonlinearity and optical bistability in a graphene-silicon waveguide resonator.

We report observation of optical bistability and enhanced thermal nonlinearity in a graphene-silicon waveguide resonator. Photo-induced Joule heating in the graphene layer gives rise to a temperature increase in the silicon waveguide core and a corresponding thermo-optic shift in the resonance of the Fabry-Perot resonator. Measurement of the nonlinear resonance spectra showed a 9-fold increase in the effective thermal nonlinear index due to the graphene layer compared with a bare silicon waveguide.

Maintenance of curve correction and unplanned return to the operating room with magnetically controlled growing rods: a cohort of 24 patients with follow-up between 2 and 7 years.

PURPOSE: Early onset scoliosis (EOS) is defined as spinal curvature affecting children below 10 years of age. Non-operative treatment can consist of casting and bracing. When curvature progresses despite these treatments, operative intervention is indicated. Traditional growing rods (TGR) have been a mainstay of treatment. Unfortunately, TGR's require planned return to the operating room every 6-9 months. Magnetic controlled growing rods (MCGR) ideally provide curve correction and allow the spine to grow without frequent surgeries. However, the ability to correct and maintain correction after MCGR has not been well-characterized. The purpose of this study is to evaluate maintenance of curve correction in patients treated primarily with MCGR and analyze the rate of complications including unplanned return to the operating room (UPROR). METHODS: 24 patients with EOS were retrospectively reviewed. These patients were subdivided into 4 subcategories: congenital, idiopathic, neuromuscular (NMS), and syndromic. The major curve correction (%) and T1-S1 distance were assessed utilizing scoliosis plain film radiographs over time. Complications and return to the operating room for any reason were recorded. Patients were followed until conversion to posterior spinal fusion (PSF) or most recent lengthening of MCGR. RESULTS: There were 11 male and 13 female patients averaging 8 years at the time of index surgery. The average preoperative curve angle was 61.1°. Initial curve correction with MCGR obtained at the index procedure was 46.2%, reducing the mean curve angle to 32.7° (p < 0.05). Curve correction at a mean 6.2 years (2.4-7.4) follow-up was 36.1°, 40.9% curve correction. 75% of patients underwent conversion to PSF during the study period 4.8 years (2.4-7.0) after initial MCGR surgery. 15% of patients were still undergoing MCGR lengthening after 6.1 years. 54.2% of patients had at least one UPROR. CONCLUSIONS: For patients with EOS with curve progression, MCGRs can maintain curve correction well after 2 years. Furthermore, MCGR allowed patients to grow over time to safely delay timing to definitive fusion. On average, patients underwent conversion to PSF after 4.7 years at an average age of 13.5. Although the complication rate in the first 2 years is relatively low, 54.2% of patients underwent an UPROR. As the use of MCGR increases, surgeons should be aware of possible complications associated with this technology and counsel patients accordingly. Further research is needed to continue to evaluate the efficacy and safety of MCGR in this challenging patient population.

Coronal Shear Fractures of the Distal Humerus.

Coronal shear fractures of the distal humerus are rare, frequently comminuted, and are without consensus for treatment. The aim of this paper is to review the current concepts on the diagnosis, classification, treatment options, surgical approaches, and complications of capitellar and trochlear fractures. Computed Tomography (CT) scans, along with the Dubberley classification, are extremely helpful in the decision-making process. Most of the fractures necessitate open reduction and internal fixation, although elbow arthroplasty is an option for comminuted fractures in the elderly low-demand patient. Stiffness is the most common complication after fixation, although reoperation is infrequent.

All-plasmonic switching based on thermal nonlinearity in a polymer plasmonic microring resonator.

We experimentally investigated thermal nonlinear effects in a hybrid Au/SiO(2)/SU-8 plasmonic microring resonator for nonlinear switching. Large ohmic loss in the metal layer gave rise to a high rate of light-to-heat conversion in the plasmonic waveguide, causing an intensity-dependent thermo-optic shift in the microring resonance. We obtained 30 times larger resonance shift in the plasmonic microring than in a similar SU-8 dielectric microring. Using an in-plane pump-and-probe configuration, we also demonstrated all-plasmonic nonlinear switching in the plasmonic microring with an on-off switching contrast of 4 dB over 50 mW input power.

Femtosecond laser tuning of silicon microring resonators.

Femtosecond laser modification is demonstrated as a possible method for postfabrication tuning of silicon microring resonators. Single 400 nm femtosecond laser pulses were used to modify the effective index of crystalline silicon microring waveguides by either amorphization or surface nanomilling depending on the laser fluence. Both blue- and redshifts in the microring resonance could be achieved without imparting significant degradation to the device quality factor.

An intraoperative laterally placed distractor for gradual load sharing correction of severe spastic neuromuscular spinal deformity.

PURPOSE: To analyze the overall deformity correction for severe neuromuscular scoliosis using laterally placed intra-operative distraction and compare to those receiving standard surgical technique. METHODS: This was a retrospective, IRB-approved, cohort study of patients with GMFCS 4 or 5 spastic cerebral palsy with neuromuscular scoliosis, age greater than 10 years, who underwent posterior spinal fusion from 2007 to 2019. All patients had vectored cervical traction with Gardner-Wells tongs, with hips flexed in a relative sitting position. The study cohort underwent intraoperative, laterally placed correction using a distractor placed between two upper ribs and the ipsilateral greater trochanter while the control cohort did not. The 24 study patients were compared to 22 control patients. RESULTS: Preoperative comparisons identified significant differences in Cobb angle, preoperative flexibility, and pelvic obliquity with the study group having larger, stiffer deformities with greater obliquity. There were no differences in pre-operative sagittal plane deformity. Mean post-operative upright Cobb angle correction was 67.3° ± 14.8° in the study and 55.3° ± 9.9° in the control group, representing a 66% and 60% correction, respectively. No neurological or other complications were noted from the use of this technique. CONCLUSION: The use of a laterally placed distraction device from upper ribs to ipsilateral greater trochanter allowed gradual lateral un-bending of large stiff neuromuscular spine deformities with greater correction than that of standard technique. In this small series, the technique allowed load-sharing during correction, with hips remaining in a functional sitting position, and without neurological complications. LEVEL OF EVIDENCE: Level III-retrospective cohort study.