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Dive into the research topics where Dominic Nielsen is active.

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Featured researches published by Dominic Nielsen.


Foot & Ankle International | 2017

Prospective, Randomized, Multi-centered Clinical Trial Assessing Safety and Efficacy of a Synthetic Cartilage Implant Versus First Metatarsophalangeal Arthrodesis in Advanced Hallux Rigidus

Judith F. Baumhauer; Dishan Singh; Mark Glazebrook; Chris Blundell; Gwyneth de Vries; Ian L. D. Le; Dominic Nielsen; M. Elizabeth Pedersen; Anthony Sakellariou; Matthew Solan; Guy Wansbrough; Alastair Younger; Timothy R. Daniels

Background: Although a variety of great toe implants have been tried in an attempt to maintain toe motion, the majority have failed with loosening, malalignment/dislocation, implant fragmentation and bone loss. In these cases, salvage to arthrodesis is more complicated and results in shortening of the ray or requires structural bone graft to reestablish length. This prospective study compared the efficacy and safety of this small (8/10 mm) hydrogel implant to the gold standard of a great toe arthrodesis for advanced-stage hallux rigidus. Methods: In this prospective, randomized non-inferiority study, patients from 12 centers in Canada and the United Kingdom were randomized (2:1) to a synthetic cartilage implant or first metatarsophalangeal (MTP) joint arthrodesis. VAS pain scale, validated outcome measures (Foot and Ankle Ability Measure [FAAM] sport scale), great toe active dorsiflexion motion, secondary procedures, radiographic assessment, and safety parameters were evaluated. Analysis was performed using intent-to-treat (ITT) and modified ITT (mITT) methodology. The primary endpoint for the study consisted of a single composite endpoint using the 3 primary study outcomes (pain, function, and safety). The individual subject’s outcome was considered a success if all of the following criteria were met: (1) improvement (decrease) from baseline in VAS pain of ≥30% at 12 months; (2) maintenance of function from baseline in FAAM sports subscore at 12 months; and (3) absence of major safety events at 2 years. The proportion of successes in each group was determined and 1-sided 95% confidence interval for the difference between treatment groups was calculated. Noninferiority of the implant to arthrodesis was considered statistically significant if the 1-sided 95% lower confidence interval was greater than the equivalence limit (<15%). A total of 236 patients were initially enrolled; 17 patients withdrew prior to randomization, 17 patients withdrew after randomization, and 22 were nonrandomized training patients, leaving 152 implant and 50 arthrodesis patients. Standard demographics and baseline outcomes were similar for both groups. Results: VAS pain scores decreased significantly in both the implant and arthrodesis groups from baseline at 12 and 24 months. Similarly, the FAAM sports and activity of daily living subscores improved significantly at 12 and 24 months in both groups. First MTP active dorsiflexion motion improvement was 6.2 degrees (27.3%) after implant placement and was maintained at 24 months. Subsequent secondary surgeries occurred in 17 (11.2%) implant patients (17 procedures) and 6 (12.0%) arthrodesis patients (7 procedures). Fourteen (9.2%) implants were removed and converted to arthrodesis, and 6 (12.0%) arthrodesis patients (7 procedures [14%]) had isolated screws or plate and screw removal. There were no cases of implant fragmentation, wear, or bone loss. When analyzing the ITT and mITT population for the primary composite outcome of VAS pain, function (FAAM sports), and safety, there was statistical equivalence between the implant and arthrodesis groups. Conclusion: A prospective, randomized (2:1), controlled, noninferiority clinical trial was performed to compare the safety and efficacy of a small synthetic cartilage bone implant to first MTP arthrodesis in patients with advanced-stage hallux rigidus. This study showed equivalent pain relief and functional outcomes. The synthetic implant was an excellent alternative to arthrodesis in patients who wished to maintain first MTP motion. The percentage of secondary surgical procedures was similar between groups. Less than 10% of the implant group required revision to arthrodesis at 2 years. Level of Evidence: Level I, prospective randomized study.


Foot & Ankle International | 2009

Minimally Invasive Paratenon Release for Non-Insertional Achilles Tendinopathy

Venunatha Naidu; Ali Abbassian; Dominic Nielsen; Raju Uppalapati; Anupkumar Shetty

Background: Non-insertional Achilles tendinopathy is an increasing, perhaps secondary to an increase in sporting activities. Traditional open surgical procedures have been associated with a significant rate of complications. We describe a minimally invasive technique involving the release of the adherent paratenon with a peritendinous infusion of corticosteroids and present the results in a cohort of patients. Materials and Methods: Twenty-nine tendons (26 patients) with non-insertional Achilles tendinopathy were treated with the above technique. Assessments were made prospectively using an adapted classification of Achilles tendon disability and a visual analogue scale for pain. Patients were interviewed in person or by telephone at an average of 14 (range, 6 to 30) months after surgery. Results: The average pain score (VAS) improved from 8.7 to 2.4 (p < 0.001) and the average Puddu level of disability improved from 4.9 to 1.7 (p < 0.001). Seventy-five percent of patients had a good or excellent outcome with 20% having sufficient improvement not to pursue further medical attention for their tendinopathy. There was a 7% rate of minor complications due to delayed wound healing which resolved spontaneously and did not affect the rehabilitation or the recovery of the patients. Conclusion: A minimally invasive circumferential paratenon release and peritendinous steroid infusion was a simple method to treat non-insertional Achilles tendinopathy and had low morbidity in our series. This technique has become our preferred primary surgical intervention for this condition. Level of Evidence: IV, Retrospective Case Series


European Journal of Orthopaedic Surgery and Traumatology | 2013

Expandable intramedullary nails for humeral fractures: a systematic review of clinical and radiological outcomes.

David Rose; Toby O. Smith; Dominic Nielsen; Caroline B. Hing

The Fixion™ system (Disc-O-Tech Medical Technologies, Herzeliya, Israel), which is currently the only expandable nailing system available for use in the humerus, has a number of purported advantages over the standard locked humeral nail, including a reduction in operating and fluoroscopy time since locking screws are not required. A systematic review was undertaken of all published (AMED, CINAHL, EMBASE and Medline via the Ovid platform) and unpublished or grey literature research databases from inception until 1st December 2010. Demographic data, clinical and radiological outcomes, and complications were extracted from each study by two independent investigators, and each study underwent independent critical appraisal using the CASP appraisal tool. Thirteen studies were deemed eligible for review, identified from a total of 154 citations. These included a total of 176 patients with 180 fractured humeri treated with expandable nails. Overall, 7.8% of humeral fractures treated with an expandable nail went on to non-union. Intra- and post-operative device failure rate was found to be 1.1 and 2.8%, respectively. These data compare favourably to published data on the outcome of locked humeral nails. However, there were numerous methodological flaws in the current evidence base; there were no comparative studies, treatment groups were heterogeneous, and there was no blinding of assessors or patients. Initial data indicate that the expandable humeral nail may be an acceptable form of treatment for humeral fracture or impending fracture, but high-quality comparative studies are needed to confirm these findings.


Foot & Ankle International | 2017

Correlation of Hallux Rigidus Grade With Motion, VAS Pain, Intraoperative Cartilage Loss, and Treatment Success for First MTP Joint Arthrodesis and Synthetic Cartilage Implant:

Judith F. Baumhauer; Dishan Singh; Mark Glazebrook; Chris Blundell; Gwyneth de Vries; Ian L. D. Le; Dominic Nielsen; M. Elizabeth Pedersen; Anthony Sakellariou; Matthew Solan; Guy Wansbrough; Alastair Younger; Timothy R. Daniels

Background: Grading systems are used to assess severity of any condition and as an aid in guiding treatment. This study examined the relationship of baseline motion, pain, and observed intraoperative cartilage loss with hallux rigidus grade. Methods: A prospective, randomized study examining outcomes of arthrodesis compared to synthetic cartilage implant was performed. Patients underwent preoperative clinical examination, radiographic assessment, hallux rigidus grade assignment, and intraoperative assessment of cartilage loss. Visual analog scale (VAS) score for pain was obtained preoperatively and at 24 months. Correlation was made between active peak dorsiflexion, VAS pain, cartilage loss, and hallux rigidus grade. Fisher’s exact test was used to assess grade impact on clinical success (P < .05). Results: In 202 patients, 59 (29%), 110 (55%), and 33 (16%) were classified as Coughlin grades 2, 3, and 4, respectively. There was no correlation between grade and active peak dorsiflexion (–0.069, P = .327) or VAS pain (–0.078, P = .271). Rank correlations between grade and cartilage loss were significant, but correlations were small. When stratified by grade, composite success rates between the 2 treatments were nearly identical. Conclusions: Irrespective of the grade, positive outcomes were demonstrated for both fusion and synthetic cartilage implant. Clinical symptoms and signs should be used to guide treatment, rather than a grade consisting of radiographic, symptoms, and range of motion factors. Level of Evidence: Level II, randomized clinical trial.


Foot & Ankle International | 2017

Association Between Patient Factors and Outcome of Synthetic Cartilage Implant Hemiarthroplasty vs First Metatarsophalangeal Joint Arthrodesis in Advanced Hallux Rigidus

Andrew Goldberg; Dishan Singh; Mark Glazebrook; Chris Blundell; Gwyneth de Vries; Ian L. D. Le; Dominic Nielsen; M. Elizabeth Pedersen; Anthony Sakellariou; Matthew Solan; Alastair Younger; Timothy R. Daniels; Judith F. Baumhauer

Background: We evaluated data from a clinical trial of first metatarsophalangeal joint (MTPJ1) implant hemiarthroplasty and arthrodesis to determine the association between patient factors and clinical outcomes. Methods: Patients ≥18 years with hallux rigidus grade 2, 3, or 4 were treated with synthetic cartilage implant MTPJ1 hemiarthroplasty or arthrodesis. Pain visual analog scale (VAS), Foot and Ankle Ability Measure (FAAM) sports and activities of daily living (ADL) scores, and Short Form-36 Physical Function (SF-36 PF) subscore were obtained preoperatively, and at 2, 6, 12, 24, 52, and 104 weeks postoperatively. Final outcome data, great toe active dorsiflexion motion, secondary procedures, radiographs, and safety parameters were evaluated for 129 implant hemiarthroplasties and 47 arthrodeses. The composite primary endpoint criteria for clinical success included VAS pain reduction ≥30%, maintenance/improvement in function, no radiographic complications, and no secondary surgical intervention at 24 months. Predictor variables included hallux rigidus grade; gender; age; body mass index (BMI); symptom duration; prior MTPJ1 surgery; preoperative hallux valgus angle, range of motion (ROM), and pain. Two-sided Fisher exact test was used (P < .05). Results: Patient demographics and baseline outcome measures were similar. Success rates between implant MTPJ1 hemiarthroplasty and arthrodesis were similar (P > .05) when stratified by hallux rigidus grade, gender, age, BMI, symptom duration, prior MTPJ1 surgery status, and preoperative VAS pain, hallux valgus, and ROM. Conclusion: Synthetic cartilage implant hemiarthroplasty was appropriate for patients with grade 2, 3, or 4 hallux rigidus. Its results in those with associated mild hallux valgus (≤20 degrees) or substantial preoperative stiffness were equivalent to MTPJ1 fusion, irrespective of gender, age, BMI, hallux rigidus grade, preoperative pain or symptom duration. Level of Evidence: Level II, randomized clinical trial.


Foot & Ankle Orthopaedics | 2018

Five-year Outcomes of a Synthetic Cartilage Implant for the First Metatarsophalangeal Joint in Advanced Hallux Rigidus

Mark Glazebrook; Chris Blundell; Dishan Singh; Gwyneth de Vries; Ian Le; Dominic Nielsen; M. Elizabeth Pedersen; Anthony Sakellariou; Matthew Solan; Guy Wansbrough; Alastair Younger; Judith F. Baumhauer; Timothy R. Daniels

Introduction/Purpose: Hallux rigidus is the most common arthritic condition of the foot. A prospective, randomized, noninferiority clinical trial of first metatarsophalangeal joint (MTPJ) hemiarthroplasty with a synthetic polyvinyl alcohol hydrogel implant, for moderate to severe hallux rigidus, demonstrated maintenance of MTPJ active dorsiflexion motion and excellent pain relief; additionally, the trial showed functional outcomes and safety equivalent to first MTPJ arthrodesis at 24 months (Baumhauer et al. 2016; FAI:37(5):457-469). Recognizing that many hemiarthroplasty and total toe implants have initially good results that deteriorate over time, the purpose of this study was to prospectively assess the safety and efficacy outcomes for the synthetic cartilage implant population and to determine if the excellent outcomes were maintained at >5 years.


Foot and Ankle Surgery | 2017

Treatment of first metatarsophalangeal joint arthritis using hemiarthroplasty with a synthetic cartilage implant or arthrodesis: A comparison of operative and recovery time

Mark Glazebrook; Alastair Younger; Timothy R. Daniels; Dishan Singh; Chris Blundell; Gwyneth de Vries; Ian L. D. Le; Dominic Nielsen; M. Elizabeth Pedersen; Anthony Sakellariou; Matthew Solan; Guy Wansbrough; Judith F. Baumhauer

BACKGROUND First metatarsophalangeal joint (MTPJ1) hemiarthroplasty using a novel synthetic cartilage implant was as effective and safe as MTPJ1 arthrodesis in a randomized clinical trial. We retrospectively evaluated operative time and recovery period for implant hemiarthroplasty (n=152) and MTPJ1 arthrodesis (n=50). METHODS Perioperative data were assessed for operative and anaesthesia times. Recovery and return to function were prospectively assessed with the Foot and Ankle Ability Measure (FAAM) Sports and Activities of Daily Living (ADL) subscales and SF-36 Physical Functioning (PF) subscore. RESULTS Mean operative time for hemiarthroplasty was 35±12.3min and 58±21.5min for arthrodesis (p<0.001). Anaesthesia duration was 28min shorter with hemiarthroplasty (p<0.001). At weeks 2 and 6 postoperative, hemiarthroplasty patients demonstrated clinically and statistically significantly higher FAAM Sport, FAAM ADL, and SF-36 PF subscores versus arthrodesis patients. CONCLUSION MTPJ1 hemiarthroplasty with a synthetic cartilage implant took less operative time and resulted in faster recovery than arthrodesis. LEVEL OF EVIDENCE III, Retrospective case control study.


Foot & Ankle Orthopaedics | 2017

2017 Roger A. Mann Award Winner: Correlation of Hallux Rigidus Coughlin Grade with First MTP Motion, Intra-operative Cartilage Loss and Treatment Success for 1st MTP Arthrodesis and Hemi-Arthroplasty

Judith F. Baumhauer; Dishan Singh; Mark Glazebrook; Chris Blundell; Gwyneth de Vries; Ian L. D. Le; Dominic Nielsen; M. Elizabeth Pedersen; Anthony Sakellariou; Matthew Solan; Guy Wansbrough; Alastair Younger; Timothy R. Daniels

Category: Midfoot/Forefoot Introduction/Purpose: Hallux rigidus (HR) is a very common symptomatic problem affecting one in 40 patients over the age of 50 years. A variety of treatment options exist and, as is common in surgery, grading systems are used to assess severity of the condition and aid in the guidance of treatment. The most commonly used grading system for HR uses radiographic images, great toe range of motion and clinical symptoms. This study examines the relationship of radiographic and motion findings to observed intra-operative cartilage loss in patients with HR and explores hallux rigidus grade and cartilage loss as predictive variables for treatment outcomes. Methods: A prospective, randomized non-inferiority study examining outcomes of arthrodesis compared to hemiarthroplasty of the first metatarsal phalangeal joint (Cartiva®) was performed.2 All randomized and treated patients were included in this study. Patients underwent pre-operative clinical examination, including measures of joint motion, radiographic assessment and HR grade. Operatively, observations of cartilage loss on the metatarsal head and opposing proximal surfaces were recorded. All patients’ data, irrespective of treatment, were aggregated and Spearman Rank Correlation coefficients used to assess for strength of correlation of active peak dorsiflexion and cartilage loss to HR grade. Outcomes data were then separated by treatment group and two-sided Fisher’s Exact test assessed these variables’ impact on clinical success (p<0.05). Results: In 202 patients, 59 (29%), 110 (55%), and 33 (16%) were classified as Coughlin1 Grades 2, 3, and 4, respectively. There was no correlation between grade and active peak dorsiflexion (-0.02, p=0.78). While rank correlations between grade and cartilage loss on the proximal phalanx and metatarsal head statistically significantly differed from zero, the magnitudes of the correlations were small, 0.176 (p=0.01) and 0.224 (p=0.001), respectively (Table 1). Among Grade 4 patients, 36.4% had no metatarsal cartilage remaining; but this was also found in 8.5% of Grade 2 patients. Similarly, 52.5% of Grade 2 patients had ≥50% metatarsal cartilage remaining; but this was also found in 21.2% of Grade 4 patients. None of the observed factors were significantly associated with likelihood of achieving composite success. Conclusion: This study examines the relationship of motion and intra-operative cartilage loss findings with a commonly used clinical and radiographic grading system for hallux rigidus. This study population included only candidates with HR considered a candidate for arthrodesis based on review of clinical symptoms however the Grade assigned maybe Coughlin Grade 2, 3 or 4. Irrespective of the Grade, positive outcomes were demonstrated within both treatment groups. The weak correlations of preoperative motion and intra-operative cartilage loss to grade suggests that clinical symptoms should be a significant determinant guiding the treatment option rather than radiographic or range of motion factors.


Cochrane Database of Systematic Reviews | 2015

Surgical fixation methods for tibial plateau fractures

Iain McNamara; Toby O. Smith; Karen L Shepherd; Allan Clark; Dominic Nielsen; Simon T. Donell; Caroline B. Hing


Strategies in Trauma and Limb Reconstruction | 2013

Expandable intramedullary nails in lower limb trauma: a systematic review of clinical and radiological outcomes

David Rose; Toby O. Smith; Dominic Nielsen; Caroline B. Hing

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Matthew Solan

Royal Surrey County Hospital

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Chris Blundell

Northern General Hospital

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Dishan Singh

Royal National Orthopaedic Hospital

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Alastair Younger

University of British Columbia

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