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Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_18 | Pages 16 - 16
1 Dec 2023
Saghir R Watson K Martin A Cohen A Newman J Rajput V
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Introduction

Knee arthroscopy can be used for ligamentous repair, reconstruction and to reduce burden of infection. Understanding and feeling confident with knee arthroscopy is therefore a highly important skillset for the orthopaedic surgeon. However, with limited training or experience, furthered by reduced practical education due to COVID-19, this skill can be under-developed amongst trainee surgeons.

Methods

At a single institution, ten junior doctors (FY1 to CT2), were recruited as a part of a five, two-hour session, training programme utilising the Simbionix® ARTHRO Mentor knee arthroscopy simulator, supplemented alongside educational guidance with a consultant orthopaedic knee surgeon. All students had minimal to no levels of prior arthroscopic experience. Exercises completed included maintaining steadiness, image centring and orientation, probe triangulation, arthroscopic knee examination, removal of loose bodies and meniscectomy. Pre and post experience questionnaires and quantitative repeat analysis on simulation exercises were undertaken to identify levels of improvement.


Orthopaedic Proceedings
Vol. 105-B, Issue SUPP_13 | Pages 58 - 58
7 Aug 2023
Saghir R Watson K Martin A Cohen A Newman J Rajput V
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Abstract

Introduction

Knee arthroscopy can be used for ligamentous repair, reconstruction and to reduce burden of infection. Understanding and feeling confident with knee arthroscopy is therefore a highly important skillset for the orthopaedic surgeon. However, with limited training or experience, furthered by reduced practical education due to COVID-19, this skill can be under-developed amongst trainee surgeons.

Methods

At a single institution, ten junior doctors (FY1 to CT2), were recruited as a part of a five, two-hour session, training programme utilising the Simbionix® ARTHRO Mentor knee arthroscopy simulator, supplemented alongside educational guidance with a consultant orthopaedic knee surgeon. All students had minimal to no levels of prior arthroscopic experience. Exercises completed included maintaining steadiness, image centering and orientation, probe triangulation, arthroscopic knee examination, removal of loose bodies, and meniscectomy. Pre and post-experience questionnaires and quantitative repeat analysis on simulation exercises were undertaken to identify levels of improvement.


Orthopaedic Proceedings
Vol. 104-B, Issue SUPP_13 | Pages 67 - 67
1 Dec 2022
Cohen D Le N Zakharia A Blackman B Slawaska-Eng D de SA D
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To determine in skeletally mature patients with a traumatic, first-time, patellar dislocation, the effect of early MPFL reconstruction versus rehabilitation on the rate of recurrent patellar dislocations and functional outcomes.

Three online databases MEDLINE, EMBASE and PubMed were searched from database inception (1946, 1974, 1966 respectively), to August 20th, 2021, for literature addressing the management of patients sustaining acute first-time patellar dislocations. Data on redislocation rates, functional outcomes using the Kujala score, and complication rates were recorded. A meta-analysis was used to pool the mean postoperative kujala score as well as calculate the proportion of patients sustaining redislocation episodes using a random effects model. A risk of bias assessment was performed for all included studies using the MINORS and Detsky scores.

Overall, there were a total of 22 studies and 1705 patients included in this review. The pooled mean redislocation rate in 18 studies comprising 1409 patients in the rehabilitation group was 31% (95% CI 25%-36%, I2 = 65%). Moreover, the pooled mean redislocation rate in five studies comprising 318 patients undergoing early MPFL reconstruction was 7% (95% CI 2%-17%, I2 = 70%). The pooled mean postoperative Kujala anterior knee pain score in three studies comprising 67 patients in the reconstructive group was 91 (95% CI 84-97, I2 = 86%), compared to a score of 81 (95% CI 78-85, I2 = 78%) in 7 studies comprising 332 patients in the rehabilitation group. The reoperation rate was 9.0% in 936 patients in the rehabilitation group and 2.2% in 322 patients in the reconstruction group.

Management of acute first-time patellar dislocations with MPFL reconstruction resulted in a lower rate of redislocation and a higher Kujala score, as well as noninferiority with respect to complication rates compared to nonoperative treatment. The paucity of high-level evidence warrants further investigation in this topic in the form of well-designed and high-powered RCTs to determine the optimal management option in these patients.


The Bone & Joint Journal
Vol. 103-B, Issue 6 Supple A | Pages 45 - 50
1 Jun 2021
Kerbel YE Johnson MA Barchick SR Cohen JS Stevenson KL Israelite CL Nelson CL

Aims

It has been shown that the preoperative modification of risk factors associated with obesity may reduce complications after total knee arthroplasty (TKA). However, the optimal method of doing so remains unclear. The aim of this study was to investigate whether a preoperative Risk Stratification Tool (RST) devised in our institution could reduce unexpected intensive care unit (ICU) transfers and 90-day emergency department (ED) visits, readmissions, and reoperations after TKA in obese patients.

Methods

We retrospectively reviewed 1,614 consecutive patients undergoing primary unilateral TKA. Their mean age was 65.1 years (17.9 to 87.7) and the mean BMI was 34.2 kg/m2 (SD 7.7). All patients underwent perioperative optimization and monitoring using the RST, which is a validated calculation tool that provides a recommendation for postoperative ICU care or increased nursing support. Patients were divided into three groups: non-obese (BMI < 30 kg/m2, n = 512); obese (BMI 30 kg/m2 to 39.9 kg/m2, n = 748); and morbidly obese (BMI > 40 kg/m2, n = 354). Logistic regression analysis was used to evaluate the outcomes among the groups adjusted for age, sex, smoking, and diabetes.


Orthopaedic Proceedings
Vol. 102-B, Issue SUPP_9 | Pages 38 - 38
1 Oct 2020
Johnson MA Kerbel YE Barchick SR Cohen JS Stevenson K Israelite CL Nelson CL
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Introduction

Previous research has indicated that preoperative modification of risk factors associated with obesity may reduce complications after TKA. However, the optimal method is still debated. This study aims to investigate whether a preoperative Risk Stratification Tool (RST) devised by our institution to optimize obese patients can reduce unexpected ICU transfers, and 90-day ED visits, readmissions, and reoperations.

Methods

We retrospectively reviewed 1,724 consecutive risk stratified patients undergoing primary unilateral TKA. The mean age was 64.8 years and average body mass index (BMI) was 34.2 kg/m2. All patients underwent preoperative optimization using the RST. We first compared our primary variables of interest between obese (BMI>30, n=1,189) and non-obese patients (n=535). Patients were then divided into 3 groups (I-non-obese, II-obese (30–39.9 kg/m2) and III-morbidly obese ((>40 kg/m2)) and logistic regression was used to evaluate outcomes among the groups adjusted for age, sex, smoking history and diabetes.


Bone & Joint Research
Vol. 9, Issue 7 | Pages 341 - 350
1 Jul 2020
Marwan Y Cohen D Alotaibi M Addar A Bernstein M Hamdy R

Aims

To systematically review the outcomes and complications of cosmetic stature lengthening.

Methods

PubMed and Embase were searched on 10 November 2019 by three reviewers independently, and all relevant studies in English published up to that date were considered based on predetermined inclusion/exclusion criteria. The search was done using “cosmetic lengthening” and “stature lengthening” as key terms. The Preferred Reporting Item for Systematic Reviews and Meta-Analyses statement was used to screen the articles.


The Bone & Joint Journal
Vol. 102-B, Issue 4 | Pages 485 - 494
1 Apr 2020
Gu A Malahias M Selemon NA Wei C Gerhard EF Cohen JS Fassihi SC Stake S Bernstein SL Chen AZ Sculco TP Cross MB Liu J Ast MP Sculco PK

Aims

The aim of this study was to determine the impact of the severity of anaemia on postoperative complications following total hip arthroplasty (THA) and total knee arthroplasty (TKA).

Methods

A retrospective cohort study was conducted using the American College of Surgeons National Quality Improvement Program (ACS-NSQIP) database. All patients who underwent primary TKA or THA between January 2012 and December 2017 were identified and stratified based upon hematocrit level. In this analysis, we defined anaemia as packed cell volume (Hct) < 36% for women and < 39% for men, and further stratified anaemia as mild anaemia (Hct 33% to 36% for women, Hct 33% to 39% for men), and moderate to severe (Hct < 33% for both men and women). Univariate and multivariate analyses were used to evaluate the incidence of multiple adverse events within 30 days of arthroplasty.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_9 | Pages 17 - 17
1 Sep 2019
Reddington M Walters S Cohen J Baxter S Cole A
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Purpose of the study

To investigate the feasibility of undertaking a definitive Randomised Controlled Trial (RCT) to determine the effectiveness of early physiotherapy for sciatica.

Methods

Patients over 18 presenting to their G.P with sciatica were eligible to participate in the study, those without a clear understanding of English or had co-morbidities preventing rehabilitation were ineligible. Process and patient reported outcomes including self-rated disability, pain and general health, were collected at baseline, 6,12 and 26 weeks post randomisation.

Participants were randomised into either early physiotherapy, receiving treatment within 2 weeks after randomisation or usual care with physiotherapy commencing 6 weeks post randomisation. Both groups received up to 6 treatment sessions of a patient-centred, goal orientated physiotherapy programme specific to their needs.


Orthopaedic Proceedings
Vol. 101-B, Issue SUPP_9 | Pages 18 - 18
1 Sep 2019
Reddington M Walters S Cohen J Baxter S Cole A
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Purpose of the study

The aims of the study were to explore the experiences of sciatica sufferers, their perceptions of physiotherapy and healthcare service provision.

Methods

This was the qualitative element of a mixed methods study investigating the feasibility of early physiotherapy for sciatica. Participants in the pilot trial consented to take part in semi-structured interviews before and after they had undertaken an individualised physiotherapy programme. Data from the interviews was examined line by line using a thematic analysis approach with key themes and sub-themes emerging.


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_3 | Pages 52 - 52
1 Apr 2018
Huish E Coury J Ummel J Casey J Cohen J
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Introduction

Management of the patellofemoral surface in total knee arthroplasty (TKA) remains a topic of debate. Incidence of anterior knee pain and incidence of repeat operation have been the focus of several recent meta-analyses, however there is little recent data regarding patients” subjective ability to kneel effectively after TKA. The purpose of this study was to compare patient reported outcomes, including reported ability to kneel, after total knee arthroplasty with and without patellar resurfacing.

Methods

Retrospective chart review of 84 consecutive patients who underwent primary TKA with patella resurfacing (56 knees) or without patella resurfacing (28 knees) having a minimum of 2.5 year follow up was performed. Oxford knee scores (OKS), visual analog pain scores (VAS), and questionnaires regarding ability to kneel were evaluated from both groups. Inability to kneel was defined as patients reporting inability or extreme difficulty with kneeling. Shapiro-Wilk test was used to determine normality of data. Mann Whitney U test was used to compare the OKS and VAS between groups. Chi square test was used to compare kneeling ability between groups. Statistical analysis was performed with SPSS version 23 (IBM, Aramonk, NY).


Orthopaedic Proceedings
Vol. 100-B, Issue SUPP_4 | Pages 53 - 53
1 Apr 2018
Lum Z Ummel J Coury J Huff K Cohen J Casey J
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Introduction

Infections in total joint arthroplasty (TJA) are a burden to the healthcare system. An infection in total joint arthroplasty costs nearly $60,000–80,000 to the system. 3 major tenets to decrease surgical site infections, focus on patient preoperative optimization, intraoperative techniques, and postoperative care. Intraoperative vancomycin powder been successful in lowering infection rates in other areas of orthopaedics.

The purpose of our study was to investigate whether topical intraoperative vancomycin powder had any effect on surgical site infection, complication rate, or reoperation rate. Our hypothesis was vancomycin powder may decrease the rate of surgical site infections without any effect on wound complications.

Materials & Methods

208 consecutive patients undergoing either total hip or total knee arthroplasty (THA or TKA) were given intraoperative vancomycin powder or none. 64 patients received vancomycin poweder compared to 164 patients who did not. All preoperative, intraoperative and postoperative management was similar. Preoperative data including age, sex, BMI, diabetes status and comorbidities were recorded. Surgical techniques included medial parapatellar or subvastus for TKA, posterolateral for THA. 90-day culture positive infection and reoperation rates were recorded.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_3 | Pages 59 - 59
1 Feb 2017
Campbell D Sharpe K Cohen R
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Introduction

Cementless tapered wedge stems have shown excellent results over the last decade. Distal potting with inadequate proximal fit, as well as failure to achieve biologic fixation has led to thigh pain, loosening and implant failure. To support a variety of patient morphologies a novel tapered wedge stem was designed with reduced distal morphology, maximizing the proximal contact of the grit blasted surface. The objective of the study was to analyze the clinical outcomes of this stem design.

Methods

Three hundred and nineteen patients enrolled into prospective, post-market multicenter studies received a novel tapered wedge stem. Clinical and patient-reported outcomes including the Harris Hip Score (HHS), Lower Extremity Activity Scale (LEAS), Short Form 12 (SF12), and Euroqol 5D Score (EQ-5D) were evaluated preoperative through two years postoperative.


Orthopaedic Proceedings
Vol. 99-B, Issue SUPP_3 | Pages 85 - 85
1 Feb 2017
Cruz A Perona P Cohen R Campbell D
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Background

Instability and dislocation are some of the most important postoperative complications and potential causes of failure that dual mobility total hip arthroplasty (THA) systems continue to address. Studies have shown that increasing the relative head size provides patients implanted with smaller and larger cups increased stability, greater ROM and a lesser incidence of impingement, without compromising clinical results. The purpose of the current study was to review clinical outcomes in three groups of primary THA patients receiving a dual mobility acetabular shell.

Methods

In two US based, post-market, multicenter studies, 450 patients received a primary cementless dual mobility THA. Patients were split into three groups based on cup size: ≤ 50mm, 52mm–56mm, and ≥ 58mm. Harris Hip Scores (HHS), Short Form 12 Physical Components (SF12 PCS), Lower Extremity Activity Scores (LEAS), and Euroqol 5D Score (EQ-5Ds) were collected preoperatively and through 2 years postoperative.


Orthopaedic Proceedings
Vol. 98-B, Issue SUPP_7 | Pages 76 - 76
1 May 2016
Duplantier N Rivere A Cohen A Chimento G
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Background

Joint replacement surgery has been shown to be successful in post solid organ transplantation patients. However, complication rates, revision rates, and overall mortality can be higher in this population compared to patients who have not undergone solid organ transplantation. Many transplant patients have a decreased life expectancy. Therefore, literature suggests that joint replacement surgery be offered to qualifying patients early on when symptomatic. This study compares the outcomes of patients who have undergone solid organ transplantation as well as a joint replacement to patients that have only undergone joint replacement surgery.

Methods

We retrospectively gathered 42 transplant (T) patients over a ten year period, 2003–2013, that underwent a liver (21) or kidney (21) transplant as well as primary total knee arthroplasty (TKA) (23) or total hip arthroplasty (THA) (19). We then gathered 42 non-transplant (NT) patients matched for procedure, age, body mass index (BMI), American Society of Anesthesiologists (ASA) score, and age adjusted Charlson co-morbidity index (ACCI) score who only underwent TKA or THA with no transplant. We used Chi-Square, T test, and multivariate analysis to compare the two groups with regard to number of complications (NOC), readmissions at 30 and 90 days post surgery, length of stay (LOS), number of intensive care unit (ICU) admissions, and total direct cost (TDC) per hospital stay.


Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_16 | Pages 45 - 45
1 Dec 2015
Finelli C Dell Aquila A Miki-Rosario N Fernandes H Dos Reis F Cohen M Abdalla R Da Silva C Murça M Nigro S Salles M
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Intramedullary nailing (IMN) has been frequently indicated to treat long bone open and closed fractures, but infection following internal fixation may have devastating consequences, with higher costs. Treatment of intramedullary nail-associated infections (IMNI) is challenging and based upon surgery and adequate antibiotic administration, which requires the correct identification of causative microorganisms. However, there have been difficulties for the microbial diagnosis of IMNI, as the peri-prosthetic tissue cultures may show no microbial growth, particularly in patients with previous use of antibiotics. Sonication have shown higher sensitivity and specificity for microbial identification on a variety of orthopedic implant-associated infections. Aim: To compare clinical and microbiological results and sensitivity for the pathogen identification obtained by conventional peri-implant tissue culture samples with culture of samples obtained by sonication of explanted IMN implants, among patients presenting IMNI of long bones.

Methods: Longitudinal prospective cohort study performed at a tertiary public hospital, ongoing since August 2011. We analyzed all patients with indication for IMN implant removal, and orthopedic-implant associated infections was defined according to previous publications addressing osteosynthesis-associated infections (Yano 2014). Minimal of 2 samples from the peri-implant tissue were taken and sent under sterile conditions to the laboratory for culture. Statistical analysis was performed McNemar's test for related proportions.

Results: We included 26 patients presenting clinical signs of IMNI, of which tissue and sonication cultures were performed for 26 (100%) and 20 (77%) patients, respectively. Among them, 88% were male, with mean age was 35.9 years (range, 19–59 yo). Causes of trauma were mainly motorcycle crashes accounting 54% of accidents; tibia and fibula were affected in 65% and 27%, respectively. Gustilo open fracture classification was grade II (35%) and IIIA (35%). First stage management with external fixation for fracture stabilization was performed in 75% of trauma patients. Sensitivity of peri-prosthetic tissue culture and sonication was 80.7% (21/26), and 95% (19/20) (p< 0.05), respectively. Only one infected patient presented negative tissue and fluid cultures. Gram-positive cocci were isolated in 75% and 79% in tissue and sonication fluid cultures, respectively. Staphylococcus aureus, coagulase-negative staphylococci, Enterococcus sp., were isolated from tissue and sonication culture in 43.5% and 36.3%, 8.7% and 22.7%, 13% and 13.7%, respectively. Polymicrobial infection was diagnosed in 3.8% (1/26) and 15.8% (3/19), patients by tissue and sonication fluid cultures (p< 0,01), respectively.

Conclusion: Sonication of retrieved infected intramedullary nails has the potential for improving the microbiological diagnosis of IMNI.


Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_16 | Pages 105 - 105
1 Dec 2015
Metsemakers W Emanuel N Cohen O Reichart M Schmid T Segal D Richards R Zaat S Moriarty T
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One of the most challenging complications in orthopedic trauma surgery is the development of infection. Improved infection prophylaxis could be achieved by providing local delivery of antibiotics directly to the tissue-implant interface. Especially implant-associated bone infections caused by antibiotic-resistant pathogens pose significant clinical challenges to treating physicians. Prophylactic strategies that act against resistant organisms, such as methicillin-resistant Staphylococcus aureus (MRSA), are urgently required.

The objective of this experimental study was to determine the efficacy of a biodegradable Polymer-Lipid Encapsulation MatriX (PLEX) loaded with the antibiotic doxycycline as a local prophylactic strategy against implant-associated osteomyelitis in a humeral non-fracture rabbit model.

Activity of the PLEX-doxycycline-coating was tested against both a doxycycline susceptible (doxyS) methicillin-susceptible S. aureus (MSSA) as well as a doxycycline-resistant (doxyR) MRSA. In a rabbit intramedullary (IM) nail-related infection model, twelve rabbits received an inoculum of a doxyS MSSA direct into the medullary cavity of the humerus. After inoculation, animals received either a PLEX-doxycycline-coated nail, or an uncoated nail. The animals were observed for four weeks. Upon euthanasia, quantitative bacteriology was performed to determine bacterial load in tissues and biofilm formation on the implant. A second study was performed with sixteen rabbits receiving a DoxyR MRSA inoculum, again in coated and uncoated groups.

In vitro elution studies revealed that 25% of the doxycycline was released from the PLEX-coated implants within the first day, followed by a 3% release per day up to day 28. Quantitative bacteriology revealed the presence of osteomyelitis in all animals receiving an uncoated nail in both the MSSA and the DoxyR MRSA studies (figure). All rabbits receiving a PLEX-doxycycline-coated nail were culture negative in the doxyS MSSA-group and the surrounding bone displayed a normal physiological appearance in both histological sections and radiographs. In the doxyR MRSA inoculated rabbits, a statistically significant reduction in the number of culture-positive samples was observed for the PLEX-doxycycline-coated group when compared to the animals that had received an uncoated nail, although the reduction in bacterial burden did not reach statistical significance.

Improved prophylaxis against infection in trauma and orthopedic implant surgery is clearly required today. In this study, we investigated a PLEX-doxycycline-coated IM nail in a humeral non-fracture rabbit model. The PLEX-doxycycline coating on titanium alloy implants provided complete protection against implant-associated MSSA osteomyelitis, and resulted in a significant reduction in the number of culture positive samples when challenged with a doxycycline-resistant MRSA.


Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_13 | Pages 12 - 12
1 Nov 2015
Cohen B
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The primary goals of successful rTSA (Reverse Total Shoulder Arthroplasty) are pain relief, improved shoulder motion and function with the restoration of patient independence. These goals can be achieved by optimal prosthesis design and surgical technique.

Historically there have been two predominant reverse shoulder design philosophies: the traditional valgus 155-degree neck-shaft angle with a medialised center of rotation introduced by Dr. Grammont, and the more recent varus 135-degree neck-shaft angle with a lateralised center of rotation, developed by Dr. Frankle. The latter design has reported lower incidences of scapular notching, coupled with improved adduction and external rotation. Over time, an understanding of the factors which resulted in clinical complications and those that contributed to the clinical success of both these design philosophies has been analyzed and widely publicised. With the currently available reverse prostheses the surgeon is required to be committed to one design philosophy or the other. This commitment to one singular design may hinder surgeons from the ability to individualise each case regardless of patient anatomy, rotator cuff condition, arthritic state and post-operative expectation.

Recently, a system has been launched which offers both design philosophies in one system, providing unsurpassed intra-operative flexibility. This allows the surgeon to adapt to each individual case and choose either design philosophy based on patient condition and anatomy, thus optimizing patient outcome.

The treatment of proximal humeral fractures has historically included Hemi Arthroplasty (HA) or Total Shoulder Arthroplasty (TSA). However, rTSA has recently become the surgery of choice for many fracture treatments based on more reproducible results. Certain implant characteristics are gaining favor in the treatment of proximal humerus fractures namely:

Press fit humeral stems - which avoid the risks of cement in-between the tuberosities which has been reported to compromise healing.

Proximal ‘box-shape’ geometry - which enables rotational stability especially in cases with proximal bone loss to promote reconstruction leading to improved healing.

135-degree neck-shaft angle - allowing a higher and more anatomic tuberosity position for more stable fixation maintains anatomical integrity of the tuberosities which has been reported as a critical factor for retaining rotator cuff function.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 251 - 251
1 Jul 2014
Emanuel N Rosenfeld Y Cohen O Estrada R Applbaum Y Barenholz Y Gustilo R David S
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Bacterial infection of bone may result in bone destruction which is difficult to cure due to poor accessibility to bone of systemically-administrated antibiotic and poor performance of currently available local antibacterial treatments. PolyPid Ltd developed a novel local drug delivery system based on self-assembly of pharmaceutically approved lipids and polymers that encapsulate doxycycline (Doxy). The formulation is self-assembled lipid matrix via the interaction of the lipids (cholesterol and synthetic phospholipids) and biocompatible - biodegradable polymer (poly-lactic-co-glycolic).

The entrapped Doxy is located within the anhydrous environment and therefore fully protected from both enzymatic and long-term water-exposure-related degradation. The fine coating of the tri-calcium phosphate (TCP) bone filler by this Doxy-containing formulation (BonyPid™) is capable of releasing intact and active drug at zero-order kinetics for a predetermined period of up to 30 days. The coating of the TCP granules with the polymer-lipids-Doxy formula (BonyPid™) did not change the granules’ macroscopic shape, but altered its color from white to pale yellow, which resemble the color of the entrapped Doxy. The average sizes of the non-coated TCP granules and the coated granules BonyPid™ were similar, as determined by measuring the widest dimension of each granule (1135±241 µm and 1072±242 µm, respectively, P=0.16). The MIC for Doxy that was released from BonyPid™ at different time points was similar to the non-encapsulated Doxy, suggesting full bioavailability of the released drug. BonyPid™ formulation structure was characterised by different physical methods including wide angle X-ray analyses (WAXS), differential scanning calorimetric (DSC) and SEM. WAXS analyses of BonyPid™ samples show a strong signal in the range of 1.3–1.8 2θ°, suggesting that the polymer and lipid TCP coating is a highly organised nano-substructure.

The principle lipid in BonyPid™ formulation is phosphatidylcholine, which constitutes more than 85% of the overall lipid mass. It was found that the length of the acyl chains (14, 16 and 18 carbons, respectively) can significantly alter the release rate of Doxy during the prolonged (30 days), zero-order release phase, but did not alter the release profile. The anti-infection activity of BonyPid™ was tested in the rabbit tibia model contaminated with 5×105S. aureus. Both acute and chronic infection models were tested. Only BonyPid™ treatment demonstrated a statistically significant reduced bone absorption over the infected group (P<0.04 for day 7, 14 and 21) and significantly lower bacterial bone concentration (p>0.05) on day 21 following the bone grafting and the bacterial inoculation. In addition it was found that BonyPid™ did not reduce the osteo-conductivity as compared to non-coated TCP bone-filler. The first-in-man study for the treatment of contaminated / infected severe open long-bone fractures of BonyPid™ completed its 6 months follow-up. The results demonstrated high safety profile and significant efficacy; early bone callus formation and 0% infections in the BonyPid™ target bone fracture.

Conclusion

Results demonstrate that BonyPid™ nan-technology that allow one month release of doxycycline in a controlled manner provides a new way for treating open fractures. This new local antibiotic delivery system is applicable in other medical situations associated with localised infections.


Orthopaedic Proceedings
Vol. 96-B, Issue SUPP_11 | Pages 268 - 268
1 Jul 2014
Doornberg J Bosse T Cohen M Jupiter J Ring D Kloen P
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Summary

In contrast to the current literature, myofibroblasts are not present in chronic posttraumatic elbow contractures.

However, myofibroblasts are present in the acute phase after an elbow fracture and/or dislocation. This suggests a physiological role in normal capsule healing and a potential role in the early phase of posttraumatic contracture formation.

Introduction

Elbow stiffness is a common complication after elbow trauma. The elbow capsule is often thickened, fibrotic and contracted upon surgical release. The limited studies available suggest that the capsule is contracted because of fibroblast to myofibroblast differentiation. However, the timeline is controversial and data on human capsules are scarce.

We hypothesise that myofibroblasts are absent in normal capsules and early after acute trauma and elevated in patients with posttraumatic elbow contracture.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_34 | Pages 267 - 267
1 Dec 2013
Cohen R
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Cementless biologic fixation surfaces on total joint replacement devices, such as those used in total hip and knee procedures, have evolved over the decades. Historically, various surfaces to allow bone ingrowth or ongrowth have been applied as a coating to a pre-formed solid metal substrate. As shown in Figure 1, from left to right, representative coating surfaces include sintered beads, diffusion-bonded fiber metal, and plasma sprayed titanium. In certain applications, tantalum porous metal (Fig 1, left) can be used without a solid metal substrate, but its most widespread usage is in a modular acetabular cup design with the porous metal diffusion-bonded to a solid metal substrate similar to other coatings. Each of these examples of biologic fixation surfaces has limitations. With comparatively low porosity, bead, fiber metal and plasma spray coatings are simply a surface enhancement onto a rigid machined, forged or cast metal substrate. Furthermore, the thermal process to apply the coatings can adversely affect the mechanical properties of the metal substrate. Released in the 1990's, tantalum porous metal is considered a ‘highly porous metal’ with twice the porosity of the applied surface coatings. With that greater porosity comes lower strength that requires engineers to make standalone tantalum porous metal shapes more bulky. The chemical deposition process to produce tantalum porous metal shapes has also limitations on geometry possibilities. Where bonding the tantalum porous metal to a solid metal substrate is necessary for adequate strength, that diffusion bonding process pressure can diminish the surface coefficient of friction necessary for initial stability.

A new class of manufacturing processing, referred to as ‘additive manufacturing’, allows engineers to create unique porous configurations. These configurations can be fabricated with beneficial properties to a specific implant application. One such enabling additive manufacturing process is called direct metal laser sintering (DMLS). This process utilizes a laser that travels over a fine powder bed. The laser path is determined by a program that mimics a computer model. Where the laser contacts the powder bed, the powder consolidates. Layer by layer, a scaffold porous metal is fabricated. Figure 2 shows a titanium alloy porous metal structure produced by DMLS. This formed biomaterial has 65% porosity, a high coefficient of friction, low stiffness, and strength that is 2 to 3 times that of tantalum porous metal. From a design versatility perspective, with greater strength, relatively thinner and more bone conserving geometries can be developed. When a solid metal surface interface to secure a modular polymer bearing is required, the DMLS process can produce the solid surface and the porous metal at the same time. With no secondary bonding thermal cycle needed, the construct's mechanical integrity is not compromised. Advancing biologic fixation necessitates bone conserving implant designs that have the properties to achieve immediate mechanical stability and longer term bone ingrowth. This novel use of DMLS in this particular porous metal geometry allows engineers to meet those criteria.