The challenge in preparing particle suspensions for aquatic microplastic research.

The occurrence of small particles consisting of organic polymers, so-called microplastic (MP), in aquatic environments attracts increasing interest in both public and science. Recent sampling campaigns in surface waters revealed substantial numbers of particles in the size range from a few micrometers to a few millimeters. In order to validate sample preparation, identification and quantification and to investigate the behavior of MP particles and potential toxic effects on organisms, defined MP model particles are needed. Many studies use spherical compounds that probably behave differently compared to irregularly shaped MP found in environmental samples. However, preparation and handling of MP particles are challenging tasks and have been systematically investigated in the present study. Polystyrene (PS) as a commonly found polymer with a density slightly above that of water was selected as polymer type for milling and fractionation studies. A cryogenic ball mill proved to be practical and effective to produce particles in the size range from 1 to 200 µm. The yield of small particles increased with increasing pre-cooling and milling durations. Depending on the concentration and the size, PS particles do not completely disperse in water and particles partly creep vertically up along glass walls. Stabilized MP suspensions without use of surfactants that might harm organisms are needed for toxicological studies. The stabilization of PS particle suspensions with ozone treatment reduced the wall effect and increased the number of dispersed PS particles but increased the dissolved organic carbon concentration and changed the size distribution of the particles.

Nonspanning Total Wrist Arthrodesis with a Low-Profile Locking Plate.

Purpose This study aims to compare the outcomes and complications of our technique for nonspanning total wrist arthrodesis using a locking plate with the standard carpometacarpal spanning technique. Methods A retrospective review of charts was performed to identify patients who underwent total wrist arthrodesis by the senior author (S.W.W.). We compared the outcomes of 15 cases of nonspanning wrist fusion with a 2.4/2.7 mm locking T plate to 11 cases of spanning wrist fusion with a 2.7/3.5 mm locking compression plate. Minimum follow-up was 3 months. Indications for fusion included rheumatoid arthritis, posttraumatic arthritis, Kienböck's disease, primary osteoarthritis, juvenile inflammatory arthropathy, psoriasis, brachial plexopathy, failed hemi or total wrist arthroplasty, failed four-corner fusion, and failed proximal row carpectomy. The primary outcome was fusion. Secondary outcomes included time to union, patient-rated wrist evaluation score, numerical rating scale pain score, grip strength, and complications. Results All the wrists got fused. There were no significant differences in objective and subjective outcomes between cohorts. There were three complications (27%) in the spanning group, including tendon rupture and peri-implant fracture at the third metacarpal. This was compared with three complications (20%) in the nonspanning group, consisting of hardware removal. Discussion We achieved similar fusion rates employing both spanning and nonspanning total wrist arthrodesis techniques, without necessitating carpometacarpal arthrodesis in the latter. Complications associated with our method were comparably less severe than those reported in the literature. We advocate nonspanning arthrodesis as an alternative method for total wrist fusion with a high union rate and minimal risk of complications at the carpometacarpal joint. Level of Evidence Therapeutic level IV.

Unicompartmental knee arthroplasty versus total knee arthroplasty: Which type of artificial joint do patients forget?

PURPOSE: During recent years, there has been an intensive growth of interest in the patient's perception of functional outcome. The Forgotten Joint Score (FJS) is a recently introduced score that measures joint awareness of patients who have undergone knee arthroplasty and is less limited by ceiling effects. The aim of this study was to compare the FJS between patients who undergo medial unicompartmental knee arthroplasty (UKA) and patients who undergo total knee arthroplasty (TKA) 1 and 2 years post-operatively. METHODS: This prospective study compares the FJS at a minimum of one (average 1.5 years, range 1.0-1.9) and a minimum of 2 years (average 2.5 years, range 2.0-3.6) post-operatively between patients who underwent medial UKA and TKA. RESULTS: One-hundred and thirty patients were included. Sixty-five patients underwent medial UKA and 65 patients underwent TKA. At both follow-up points, the FJS was significantly higher in the UKA group (FJS 1 year 73.9 ± 22.8, FJS 2 year 74.3 ± 24.8) in contrast to the TKA group (FJS 1 year 59.3 ± 29.5 (p = 0.002), FJS 2 year 59.8 ± 31.5, (p = 0.004)). No significant improvement in the FJS was observed between 1- and 2-year follow-up of the two cohorts. CONCLUSION: Patients who undergo UKA are more likely to forget their artificial joint in daily life and consequently may be more satisfied. LEVEL OF EVIDENCE: II.

Outcomes after operative treatment of elbow contractures in the pediatric and adolescent population.

BACKGROUND: The role of elbow contracture release in the very young is unclear, with existing studies reporting conflicting results. This study evaluated the long-term results after open elbow contracture release in patients aged younger than 18 years. METHODS: Between 1994 and 2012, 32 patients underwent open elbow contracture release at a mean age of 13.8 years (range, 5-18 years), and their outcomes were reviewed. The primary cause was traumatic in 30 patients (4 radial head/neck fractures, 5 intra-articular distal humeral fractures, 11 extra-articular distal humeral fractures, 10 complex fracture-dislocations), and the mean time from the index injury to contracture release was 16.3 months (range, 3-82 months). The cause in 2 patients was nontraumatic (1 osteochondritis dessicans, 1 congenital). The mean follow-up period was 66 months (range, 7-202 months). RESULTS: At the latest follow-up, total arc of motion improved from 69° to 123° (P <.0001), with a mean increase of 54° (P <.0001). The function arc was >100° in 28 patients (88%), and 29 patients (91%) achieved >20° of improvement in their arc. Twelve patients (38%) underwent a gentle manipulation under anesthesia at a mean of 2.7 weeks (range, 1-5 weeks) for early recurrence of stiffness. There were 3 complications (1 deep infection, 1 hematoma, 1 humeral fracture through the external fixator pin site). No patients lost motion after surgery. CONCLUSION: Elbow contracture release in the pediatric and adolescent population can provide significant improvements in range of motion similar to that achieved in adults. The improvements in motion are durable.

Onlay tibial implants appear to provide superior clinical results in robotic unicompartmental knee arthroplasty.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is an increasingly popular option for the treatment of single-compartment knee osteoarthritis (OA) in adults. Two options for tibial resurfacing during UKA are (1) all-polyethylene inlays and (2) metal-backed onlays. QUESTIONS/PURPOSES: The aim of this study was to determine whether there are any differences in clinical outcomes with inlay versus onlay tibial components. PATIENTS AND METHODS: We identified 39 inlays and 45 onlays, with average 2.7- and 2.3-year follow-up, respectively, from a prospective robotic-assisted surgery database. The primary outcome was the Western Ontario and McMaster University Arthritis Index (WOMAC), subcategorized by the pain, stiffness, and function subscores, at 2 years postoperatively. The secondary outcome was the need for secondary or revision surgery. RESULTS: Postoperative WOMAC pain score was 3.1 for inlays and 1.6 for onlays (p = 0.03). For 25 inlays and 30 onlays with both preoperative and postoperative WOMAC data, pain score improved from 8.3 to 4.0 for inlays versus from 9.2 to 1.7 for onlays (p = 0.01). Function score improved from 27.5 to 12.5 for inlays versus from 32.1 to 7.3 for onlays (p = 0.03). Four inlays and one onlay required a secondary or revision procedure (p = 0.18). CONCLUSIONS: We advise using metal-backed onlays during UKA to improve postoperative clinical outcomes.

Conservative management of elbow dislocations with an overhead motion protocol.

PURPOSE: To report the results of using an overhead motion protocol in 27 patients and to assess final range of motion and incidence of persistent instability in this cohort. METHODS: A total of 27 patients were included who sustained a simple elbow dislocation and were treated nonsurgically with an overhead motion protocol designed to convert gravity from a distracting to a stabilizing force. Motion was initiated within 1 week of injury and average follow-up was 29 months. Final arc of motion and prevalence of instability were the primary outcomes measures. RESULTS: Final mean arc of extension to flexion was from 6° to 137°, and of pronation to supination was from 87° to 86°. No recurrent instability was observed in this cohort and all patients were fully functional and without limitations at latest follow-up. CONCLUSIONS: The overhead motion protocol was a reliable rehabilitation program after elbow dislocation that allowed for controlled early motion by placing the elbow in an inherently stable position. Prompt initiation of motion in a protected position can optimize final motion and satisfaction outcomes, and when done in a mechanically advantageous position it can potentially limit the risk of recurrent instability. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Outcomes of anconeus interposition for proximal radioulnar synostosis.

BACKGROUND/HYPOTHESIS: Proximal radioulnar synostosis after elbow injuries can produce debilitating contractures. The estimated range of motion required to perform many activities of daily living is a 100° arc of forearm rotation. We hypothesized that excision of heterotopic bone and anconeus flap interposition could restore functional prono-supination in patients with proximal radioulnar synostosis. METHODS: Patients with proximal radioulnar synostosis were subdivided into 2 groups on the basis of etiology: (1) as a complication after distal biceps tendon repair or (2) as a result of direct trauma to the proximal forearm/elbow. All patients underwent an excision of the synostosis with interposition of an anconeus flap and were observed clinically for a minimum of 6 months. RESULTS: Twenty-three patients (16 men, 7 women) were included, with a mean age of 47 years and mean clinical follow-up of 4.8 years. Mean arc of forearm rotation improved from 21° to 132°, pronation increased from 12° to 70°, and supination increased from 9° to 62° (P < .0001). Patients with biceps tendon repair etiology (n = 7) displayed greater gains in pronation and a trend toward greater total forearm rotation than did those with a traumatic etiology (n = 16). CONCLUSION: Anconeus interposition flap for management of proximal radioulnar synostosis produces significant and reliable clinical improvement in elbow prono-supination. Patients with biceps tendon repair etiology had a trend toward greater motion improvement than that of patients with a traumatic etiology. The degree of improvement seen would provide nearly full restoration of functional motion, resulting in minimal limitations in activities of daily living.

Is tibiofemoral subluxation correctable in unicompartmental knee arthroplasty?

The purposes of this study were to describe a method for measuring tibiofemoral subluxation in UKA, and to report the mean amount of tibiofemoral subluxation seen both preoperatively and postoperatively in a cohort of patients undergoing UKA. Two hundred thirty-five patients who received a medial UKA, and 39 patients who received a lateral UKA, were reviewed. In the medial UKA cohort, the mechanical alignment was corrected from 7.7° ± 5.9° preoperatively, to 2.9° ± 2.5° postoperatively, while the tibiofemoral subluxation was corrected from 4.5 mm ± 3.0 mm preoperatively, to 2.3 mm ± 2.7 mm postoperatively. In the lateral UKA cohort, the mechanical alignment was corrected from -5.5° ± 3.8° to -1.6° ± 3.4°, while the tibiofemoral subluxation was corrected from 4.3 mm ± 2.7 mm to 2.8 mm ± 2.5mm. This study presents a novel method for measurement of tibiofemoral subluxation, the mean amount of tibiofemoral subluxation present preoperatively, and the amount of correction that can be expected during both medial and lateral unicondylar knee arthroplasty.