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Orthopaedic Proceedings
Vol. 97-B, Issue SUPP_3 | Pages 13 - 13
1 Apr 2015
Augustithis G Huntley J
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‘Safety’ is at the centre of surgical practice with the aim of minimising the risks of complications and adverse events. Much evidence, based on either retrospective case series or prospective cohorts, concerns the frequency of adverse events. There may be a temptation to describe a procedure as ‘safe’ if no – or few – serious adverse events (the numerator) have occurred out of a number of procedures performed (the denominator). In 1983, Hanley and Lippman-Hand described a simple algorithm to calculate the 95% upper Confidence Interval for data sets in which the numerator is zero (ie series in which there no adverse events). Paediatric orthopaedics suffers from small datasets which may make its researchers especially prone to the erroneous attribution of procedures being ‘safe’. The aim of the current study was to formally assess the evidence on which paediatric orthopaedic surgical procedures are described as ‘safe’. In particular, the objective was to ascertain the proportion of studies describing a procedure as ‘safe’ which achieved a 95% upper limit Confidence Interval of risk of 5% for major adverse events.

We examined all papers published by the Journal of Paediatric Orthopaedics in the previous 5 years searching for the single term ‘safe’. 84 papers were returned and 71 were considered appropriate for analysis. Of these 60 papers positively identified their intervention as ‘safe’. These papers were read in full and the number of interventions was recorded along with the rate of complication. 66 data sets were created and the 95% upper confidence interval was calculated for complication rates. Only 16 out of 66 data sets could safely predict a major complication rate of under 5%.

Our work would tend to suggest that a failure to apply proper statistical tools is leading to procedures being erroneously classified as safe in the published literature.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_33 | Pages 4 - 4
1 Sep 2013
Marsh A Robertson J Godman A Boyle J Huntley J
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Neurological examination in children presenting with upper limb fractures is often poorly performed. We aimed to assess the quality of documented neurological examination in children presenting with upper limb fractures and whether this could be improved following introduction of a simple guideline for paediatric neurological assessment.

We reviewed the clinical notes of all children presenting to the emergency department with upper limb fractures over a three month period. Documentation of initial neurological assessment and clinical suspicion of any nerve injury were noted. Subsequently, we introduced a guideline for paediatric upper limb neurological examination (‘Rock, Paper, Scissors, OK’) to our own hospital and performed a further 3 month clinical review to detect any resulting change in practice.

In the initial study period, 121 patients presented with upper limb fractures. 10 children (8%) had a nerve injury. Neurological examination was documented in 107 (88%) of patients, however, none of the nerve injuries were detected on initial assessment. In patients with nerve injuries, 5 (50%) were documented as being ‘neurovascularly intact’ and 2 (20%) had no documented examination.

Following introduction of the guideline, 97 patients presented with upper limb fractures of which 8 children (8%) had a nerve injury. Documentation of neurological examination increased to 98% for patients presenting directly to our own hospital (p=0.02). Within this cohort all nerve injuries with objective motor or sensory deficits were detected on initial examination.

Introduction of a simple guideline for neurological examination in children with upper limb fractures can significantly improve the quality of documented neurological assessment and detection of nerve injuries.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_31 | Pages 34 - 34
1 Aug 2013
Fraser-Moodie J Bell S Huntley J
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Introduction

Two randomised trials concluded cast type (above or below elbow) makes no significant difference in the re-displacement rate of paediatric forearm fractures involving the distal third of the radius. This has not, however, led to the universal use of below elbow casts. In particular we noted one trial reported significant re-displacement in 40% or more of cases, which was much higher than we would expect.

To review the radiological outcomes and need for re-manipulation of paediatric distal forearm fractures treated with closed manipulation under anaesthesia in our institution, in part for subsequent comparison with published results.

All forearm fractures treated at a specialist children's hospital in one year were reviewed retrospectively. Based on the methodology of one trial, we included all fractures involving the distal third of the radius, with or without an ulna fracture, which underwent closed manipulation. Outcomes were radiological alignment using existing radiographs and need for re-manipulation. Cast type was at the discretion of the treating surgeon. The radiological criteria for re-displacement were based on published methodology.

79 children underwent manipulation, 71 receiving above elbow casts and 8 below elbow casts. Radiologically 21% of injuries treated in an above elbow cast re-displaced (15/71) compared to 38% of those in below elbow plasters (3/8). In 2 cases the re-displacement was treated with re-manipulation.

The preference in our institution was clearly for above elbow casts in this injury pattern. The small number of below elbow casts in our series limits any comparisons. Our rate of re-displacement using above elbow casts was half that of one of the published studies, so the existing literature is not consistent with our experience.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_31 | Pages 3 - 3
1 Aug 2013
Marsh A Robertson J Godman A Boyle J Huntley J
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Neurological examination in children presenting with upper limb fractures is often poorly performed. In the peripatetic emergency department environment this may be confounded by patient distress or reduced comprehension. We aimed to assess the quality of documented neurological examination in children presenting with upper limb fractures and whether this could be improved following introduction of a simple guideline for paediatric neurological assessment.

We reviewed the clinical notes of all children presenting to the emergency department with upper limb fractures over a three month period. Documentation of initial neurological assessment and clinical suspicion of any nerve injury were noted. Subsequently, we introduced a guideline for paediatric upper limb neurological examination (‘Rock, Paper, Scissors, OK’) to our hospital and performed a further 3 month review to detect resulting changes in practice.

In the initial study period, 121 children presented with upper limb fractures. 10 (8%) had a nerve injury. Neurological examination was documented in 107 (88%) of patients. However, information on nerves examined was only recorded in 5 (5%) with the majority (85%) documented as ‘neurovascuarly intact’. None of the nerve injuries were detected on initial assessment.

Following guideline introduction, 97 patients presented with upper limb fractures of which 8 children (8%) had a nerve injury. Documentation of neurological examination increased to 98% for patients presenting directly to our own hospital (Fisher's Exact Test, p=0.02) with details of nerves examined increasing to 69%. Within this cohort all nerve injuries with objective motor or sensory deficits were detected on initial examination.

The recent British Orthopaedic Association Standards for Trauma (BOAST) guideline on peripheral nerve injuries emphasises the importance of clearly recorded neurological assessment in trauma patients. Our study shows that introduction of a simple guideline for neurological examination in children with upper limb fractures can significantly improve the quality of documented neurological assessment and detection of nerve injuries.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_30 | Pages 10 - 10
1 Aug 2013
Cree C Jenkins P Huntley J
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There is substantial concern about the state of musculoskeletal knowledge of junior doctors. There are also marked differences in the locomotor curricula of medical schools, raising the possibility that students may be selectively disadvantaged from gaining appropriate knowledge and/or attaining a musculoskeletal career path. The aims of this study were to assess the musculoskeletal knowledge of newly qualified doctors in the south of Scotland, and to compare this between the two medical schools (Glasgow and Edinburgh) that have different locomotor teaching programmes.

All final year medical students, from Glasgow and Edinburgh Universities (n=158 and 221, respectively), attending the compulsory ‘Preparation for Practice’ lecture course immediately after (Glasgow) or before (Edinburgh) final exams, were assessed by the Freedman and Bernstein musculoskeletal examination, previously validated with two different pass-standards: (i) 73.1% (by orthopaedic surgeons), and (ii) 70% (by physicians).

There was a significant difference (Wilcoxon two sample test; p<0.5×10−9) in the marks obtained at the two institutions, the median being 59% (IQR 50–67%) and 68% (IQR 60–76%) at Glasgow and Edinburgh respectively. The pass-rates for the two institutions (Glasgow vs. Edinburgh) were markedly different, being 17.1% vs. 32.6% for the higher pass-mark, and 21.5% vs. 48% for the lower.

The majority of newly qualified doctors in the south of Scotland have inadequate musculoskeletal knowledge. There is a substantial and statistically significant difference in the scores attained by students from two neighbouring medical schools (Glasgow and Edinburgh). The striking difference in the pass-rates can be best explained by differences in respective musculoskeletal courses. These explicit and comparative deficits raise substantial questions for musculoskeletal curriculum planning, teaching, assessment and quality assurance.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_30 | Pages 59 - 59
1 Aug 2013
Marsh A Roberston J Boyle J Huntley J
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Neurological examination is essential in patients with upper limb injuries and should be clearly documented. We aimed to assess the quality and documentation of neurological examination performed for children presenting with upper limb fractures to the emergency department.

Clinical notes of all children admitted with upper limb fractures over a three month period were reviewed. Documentation of initial neurological assessment was analysed and clinical suspicion of any nerve injury noted. In parallel, we conducted an anonymous survey of emergency doctors evaluating their upper limb neurological examination in children.

The casenotes of 121 children with upper limb fractures were reviewed. 10 children (8%) had a nerve injury (median = 4, ulnar = 2, radial = 2, anterior interosseous = 2). Neurological examination was documented in 107 (88%) of patients. However, none of the nerve injuries were detected on initial examination. In patients with nerve injuries, 5 (50%) were documented as being ‘neurovascularly intact’, 2 (20%) as ‘CSM normal’, 1 (10%) as ‘moving fingers’ and 2 (20%) had no documented neurological examination.

30 emergency doctors completed the questionnaires (5 consultants, 9 registrars, 16 foundation doctors). All doctors stated that they routinely performed an upper limb neurological examination and assessed median, ulnar and radial nerves. However, 30% of doctors described incomplete examination of median nerve function, 30% inadequate ulnar nerve assessment and 50% incomplete radial nerve examination. In addition, 75% of doctors failed to identify the need for assessment of anterior interosseous nerve function.

While emergency doctors recognise the importance of neurological assessment in children with upper limb injuries, it is often performed inadequately. This in part may be due to difficulties performing neurological examination in paediatric patients. As a result of this study, we have introduced local guidelines to assist neurological assessment in children.


Orthopaedic Proceedings
Vol. 95-B, Issue SUPP_10 | Pages 8 - 8
1 Feb 2013
Cree C Jenkins P Huntley J
Full Access

There is substantial concern about the state of musculoskeletal knowledge of junior doctors. There are also marked differences in the locomotor curricula of medical schools, raising the possibility that students may be selectively disadvantaged from gaining appropriate knowledge and/or attaining a musculoskeletal career path. The aims of this study were to assess the musculoskeletal knowledge of newly qualified doctors in the south of Scotland, and to compare this between the two medical schools (Glasgow and Edinburgh) that have different locomotor teaching programmes.

All final year medical students, from Glasgow and Edinburgh Universities (n=158 and 221, respectively), attending the compulsory ‘Preparation for Practice’ lecture course immediately after (Glasgow) or before (Edinburgh) final exams, were assessed by the Freedman and Bernstein musculoskeletal examination, previously validated with two different pass-standards: (i) 73.1% (by orthopaedic surgeons), and (ii) 70% (by physicians).

There was a significant difference (Wilcoxon two sample test; p<0.5×10−9) in the marks obtained at the two institutions, the median being 59% (IQR 50–67%) and 68% (IQR 60–76%) at Glasgow and Edinburgh respectively. The pass-rates for the two institutions (Glasgow vs. Edinburgh) were markedly different, being 17.1% vs. 32.6% for the higher pass-mark, and 21.5% vs. 48% for the lower.

The majority of newly qualified doctors in the south of Scotland have inadequate musculoskeletal knowledge. There is a substantial and statistically significant difference in the scores attained by students from two neighbouring medical schools (Glasgow and Edinburgh). The striking difference in the pass-rates can be best explained by differences in respective musculoskeletal courses. These explicit and comparative deficits raise substantial questions for musculoskeletal curriculum planning, teaching, assessment and quality assurance.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIV | Pages 20 - 20
1 Jul 2012
Frame M Huntley J
Full Access

3D printing an additive manufacturing technique, allowing for rapid prototyping in many industries. To date, medical applications have generally been within a research or industry environment, as the costs (expertise, software and equipment) have been prohibitive.

We have established a means by which 3D printing of bones can be achieved quickly, cost-effectively and accurately from standard computer tomography (CT) digital imaging and communications in medicine (DICOM) data.

CT DICOM data of a malunited forearm fracture were manipulated using open-source software (no cost) and a 3D model was produced by selective-laser-sintering. The entire process took 7 days (total cost £77). This process and the resultant model were then assessed for overall accuracy.

This sequential methodology provides ready and economical access to a technology that is valuable for preoperative templating/rehearsal in complex 3D reconstructive cases.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXXIV | Pages 21 - 21
1 Jul 2012
Huntley J Frame M McCaul J Little K Irwin G
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Rapid prototyping (RP), especially useful in surgical specialities involving critical three-dimensional relationships, has recently become cheaper to access both in terms of file processing and commercially available printing resources.

One potential problem has been the accuracy of models generated. We performed computed tomography on a cadaveric human patella followed by data conversion using open source software through to selective-laser-sintering of a polyamide model, to allow comparative morphometric measurements (bone v. model) using vernier calipers. Statistical testing was with Student's t-test.

No significant differences in the dimensional measurements could be demonstrated. These data provide us with optimism as to the accuracy of the technology, and the feasibility of using RP cheaply to generate appropriate models for operative rehearsal of intricate orthopaedic procedures.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXVIII | Pages 24 - 24
1 Jun 2012
Betts H Rowland D Murnaghan C Walker C Huntley J
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During the cold snap in the West of Scotland 20 December 2009 to 10 January 2010 there was a cluster of uncommon lower limb injuries in children from sledging accidents. These cases are presented as a series.

This retrospective descriptive study details acute orthopaedic admissions for the period of the cold snap. The case-notes for all admissions were reviewed for diagnosis, mechanism of injury.

Five (ex 20 ie 1/4) trauma admissions involved sledging: (1) combined avulsion of anterior and posterior cruciate ligaments left knee (2) Lisfranc injury, (3) distal femoral fracture, (4) distal tibial plafond fracture, (5) pelvis, patella also forearm and facial fractures. These cases are analysed in more detail

Sledging injuries comprise a substantial portion of workload and morbidity. In children, there is a propensity for lower limb and higher energy trauma. Tertiary referrals and non-standard trauma equipment may be required.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XXVIII | Pages 47 - 47
1 Jun 2012
Donaldson D Shaw L Huntley J
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Ponseti first advocated his treatment for idiopathic clubfoot in the early 1950's. The method has only gained popularity and widespread use since the 1990's. Despite publications showing favourable results, there is little published data scrutinising the change in modes of talipes treatment. This study sought to define the trends in treatment for Idiopathic Clubfoot in Scotland over a twelve-year period (1997 – 2008).

(i) A review was performed to identify the number of publications referencing the Ponseti method over the past 40 years. (ii) A structured questionnaire was sent to all Paediatric Orthopaedic practitioners in Scotland to ascertain the treatment methods used and over the time period. (iii) Data from the National Census for number of live births were combined with that obtained from the Scottish Morbidity Record (SMR01) for number of peritalar clubfoot surgeries performed over the study period. (iv) Similar data was also obtained for non-Talipes related peritalar surgeries, and data colleceted for the number of Tibialis Anterior transfer operations for this period. Clubfoot incidence data was measured indirectly by means of sample from the database of a tertiary referral Paediatric Orthopaedic Unit. Regression analysis was used to evaluate the trends over time.

Review of the literature referencing the Ponseti method over the past 40 years showed an exponential increase from the late 1990's. The survey of Clubfoot management of Paediatric Orthopaedic Surgeons in Scotland showed a marked increase in use of the method over with this period. Over this period, the number of operations for clubfoot dropped substantially, from 55 releases in 1997 to 1 release in 2008. The linear equation estimated a decrease of approximately 5 surgical releases per year (R²= 0.87, p<0.05). In Scotland, most Tibialis Anterior transfers are performed at age 3years, the frequency of the procedure has increased in the latter half of the study period.

In Scotland between 1997 and 2008, the number of peritalar (posterior, medial, posteromedial release) operations used in the primary treatment of idiopathic clubfoot has dropped substantially. This correlates with a marked increase in reference to the method within the literature and increased usage of the Ponseti technique by Paediatric Orthopaedic Consultants.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XI | Pages 17 - 17
1 Apr 2012
Miller N Duncan R Huntley J
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Pyomyositis is a primary pyogenic infection in skeletal muscle, often progressing to abscess formation. It is rare in temperate climates and generally deep-seated within the pelvis with non-specific clinical features, making diagnosis difficult. Magnetic Resonance Imaging (MRI) is highly sensitive for muscle inflammation and fluid collection and with its increasing availability is now the investigation of choice. Treatment of pyomyositis abscess has traditionally been with incision and drainage or guided aspiration followed by a prolonged course of antibiotics, although there are sporadic reports of cases treated successfully with antibiotics alone. From our 20 year database of over 16000 paediatric orthopaedic admissions we identified only 3 cases with MRI-confirmed pyomyositis abscess. These were all in boys (aged 2-12) and affected the gluteal, piriformis and adductor muscles. Despite the organisms not being identified, each patient was treated successfully with a short (4-7 day) course of intravenous antibiotics followed by 2-6 weeks of oral therapy. There were no recurrences or complications and all made a full recovery. We propose that uncomplicated pyomyositis abscess in children may usually be managed conservatively without the need for open or percutaneous drainage.


Orthopaedic Proceedings
Vol. 94-B, Issue SUPP_XI | Pages 29 - 29
1 Apr 2012
Bell S McLaughlin D Huntley J
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Forearm fractures are a common paediatric injury. This study was aimed to describe the epidemiological of paediatric forearm fractures in the urban population of Glasgow.

We reviewed of all the forearm fracture treated by the orthopaedic service in Yorkhill Children's Hospital in 2008. Datum gathered from case notes and radiographs using the prospective orthopaedic database to identify patients with forearm fractures. The age, sex, side and type of fracture, the timing and mechanism of the injury and treatment were documented for the 436 fractures. Census data were used to derive absolute age-specific incidences.

Distinction was made between torus and other types of fractures. Torus fractures require no specific orthopaedic treatment and were segregated out. For the remaining 314 fractures, the age and sex distribution, seasonal variation of fractures and treatments for each type of fracture were examined. The incidence of forearm fractures in our population is 411 fractures per 100,000 population per year. An increased number of fractures occurred during the months of May and August. A fall from less than one metre was the commonest mechanism of injury, sporting injuries were the second commonest with football the most common sport associated.

This study identifies some features which are in good agreement with studies from elsewhere in Britain, such as incidence and seasonality. However, there are also interesting differences – such as the Glasgow peak incidence for forearm fractures being at age 8, with a marked decline by 12 years. Furthermore, our findings have been extended to consideration of type of intervention, and likelihood of successful treatment.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 56 - 56
1 Mar 2010
Amin* A Huntley J Simpson A Hall A
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Articular cartilage is attached to subchondral bone but little is known regarding bone-cartilage interactions important for chondrocyte survival. In this study, bovine articular cartilage has been evaluated in vitro to determine if the presence of subchondral bone influences chondrocyte survival. We hypothesised that

Excision of subchondral bone from articular cartilage would increase in situ chondrocyte death in explant culture and,

Chondrocyte death could be abrogated by co-culturing articular cartilage with the excised subchondral bone.

Articular cartilage explants (n=132) harvested from the metacarpophalangeal joints of three-year old cows (N=12) were placed into three groups:

subchondral bone excised from articular cartilage (Group A)

sub-chondral bone left attached to articular cartilage (Group B)

subchondral bone excised, but co-cultured with articular cartilage (Group C).

Explants were cultured in serum-free media over 7 days with or without media changes to assess the effect of potential soluble mediators. Using confocal laser scanning microscopy to image in situ chondrocytes, fluorescent probes to determine cell viability and biochemical assays to detect alterations in the culture media, differences in the chondrocyte responses (cell density, spatial distribution, percentage cell death) and culture medium composition between Groups A, B and C were quantified over time (2.5 hours versus 7 days).

There was no significant change in cell density for Groups A, B and C over 7 days (t-test, p> 0.05). With excision of subchondral bone from articular cartilage (Group A), there was a marked increase in chondrocyte death over 7 days primarily within the superficial zone involving an extensive area of the articular surface (p< 0.05). There was no significant increase in chondrocyte death over the same time period for Groups B and C (p> 0.05). Corresponding increases in the protein content of the culture media for Groups B and C but not for Group A, suggested that the release of soluble factors from subchondral bone may have influenced chondrocyte survival in the superficial zone.

Subchondral bone interacts with articular cartilage in vitro and promotes chondrocyte survival in the superficial zone. These data support the concept of a functional bone-cartilage system in vivo.


Orthopaedic Proceedings
Vol. 92-B, Issue SUPP_I | Pages 60 - 60
1 Mar 2010
Amin* A Huntley J Simpson A Hall A
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0.9% Saline and Hartmann’s are commonly used joint irrigating solutions during articular surgery. The objective of the study was to determine whether the osmolarity of these solutions affects chondrocyte death in mechanically injured articular cartilage.

The osmolarity of 0.9% Saline (285 mOsm) and Hartmann’s (255 mOsm) solutions was varied from 100–600 mOsm by the addition of distilled water or sucrose. Osteochondral explants (rectangular blocks, n=72) harvested from the metacarpophalangeal joints of six different three-year old cows were exposed to prepared solutions of different osmolarity for 2 minutes to allow in situ chondrocytes (cells embedded within their native extracellular matrix) to respond to the altered osmotic environment. Explants were then mechanically injured through the full thickness of articular cartilage with a fresh scalpel and incubated in the same solution for 2.5 hours. Using confocal laser scanning microscopy (CLSM) and fluorescent probes to determine cell viability, percentage cell death (PCD, 100 × number of dead cells/number of dead and live cells) was quantified within the full thickness of mechanically injured articular cartilage as a function of solution osmolarity.

Cell death was localised to the superficial zone (first 100 microns from the articular surface) of injured cartilage for explants exposed to the control 0.9% Saline (285 mOsm) and Hartmann’s (255 mOsm) solutions, with relative sparing of the middle and deep zones (analysis of variance (ANOVA), p< 0.05). Compared to the control explants exposed to 0.9% Saline, PCD in the superficial zone was greatest for the low osmolarity (100 mOsm) saline solution and least for the high osmolarity (600 mOsm) saline solution (ANOVA, p=0.04). PCD in the superficial zone significantly decreased for explants exposed to 600 mOsm solutions of 0.9% Saline and Hartmann’s, compared to their respective control solutions (p< 0.05 for paired comparisons). There was no significant difference in the PCD between 600 mOsm solutions of 0.9% Saline and Hartmann’s (p=0.5).

Increasing the osmolarity of 0.9% Saline and Hartmann’s solutions is chondroprotective in a surgically relevant model of mechanical cartilage injury. These experiments have important clinical relevance for the design of irrigation solutions during arthroscopic and open articular surgery.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_III | Pages 392 - 392
1 Oct 2006
Huntley J Brenkel I McBirnie J Simpson A Hall A
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Autologous osteochondral cylinder transfer is a treatment option for small articular defects, especially those arising from trauma or osteochondritis dissecans. There are concerns about graft integration and the nature of tissue forming the cartilage-cartilage bridge. Chondrocyte viability at graft and recipient edges is thought to be an important determinant of quality of repair. The aim was to evaluate cell viability at the graft edge from ex vivo human femoral condyles, after harvest using conventional technique. With ethical approval and patient consent, fresh human tissue was obtained at total knee arthroplasty. Osteochondral plugs were harvested using the commercially available Acufex 4.5mm diameter mosaicplasty osteotome from regions of the lateral femoral condyle (anterior cut) that were macroscopically non-degenerate and microscopically non-fibrillated. Plugs were assessed for chondrocyte viability at the graft edge using confocal laser scanning microscopy (CLSM), fluorescent indicators and image analysis. The central portions of the plugs remained healthy, with > 99% cell viability (n=5). However, there was substantial marginal cell death, of thickness 382 ± 68.2 microm in the superficial zone (SZ). Demi-plugs were created by splitting the mosaicplasty explants with a fresh No. 11 scalpel blade. The margin of SZ cell death was 390.3 ± 18.8 microm at the curved edge of the Acufex, significantly (Mann-Whitney; P= 0.0286; n =4) greater than that at the scalpel cut (34.8 ± 3.2 microm). Findings were similar when the cartilage was breached but the bone left intact. In time-course experiments, the SZ marginal zone of cell death after Acufex harvest showed no increase over the time period 15 minutes to 2 hours. Mathematical modelling of the mosaicplasty surface shows that cell death of this magnitude results in a disturbing 33% of the superficial graft area being non-viable. In conclusion, mosaicplasty, though capable of transposing viable hyaline cartilage, is associated with an extensive margin of cell death that is likely to compromise lateral integration. There would appear to be considerable scope for improvement of osteochondral transplant techniques which may improve graft-recipient healing and clinical outcomes.


Orthopaedic Proceedings
Vol. 88-B, Issue SUPP_III | Pages 369 - 369
1 Oct 2006
Bush P Huntley J Macnicol M Hall A
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Introduction: In the growth plate, chondrocyte swelling (hypertrophy) is a crucial event during endochondral ossification and bone lengthening, accounting for ~80% of the increase in bone length (1,3). The swelling is dramatic (~10x) and closely regulated. Failure of chondrocyte hypertrophy may underlie the chondrodysplasias of the vertebrate skeleton (1). However, the mechanisms which control cell swelling are poorly understood although there must be a key role for chondrocyte osmolyte transporters which are sensitive to an increase in cell volume. We have used confocal scanning laser microscopy (CLSM) to study volume regulation by living in situ growth plate chondrocytes at varying degrees of hypertrophy.

Methods: Bovine growth plates were taken from the ends of young (~12d) bovine ribs. In situ growth plate chondrocytes at the proliferative through to hypertrophic stages were fluorescently-labelled (calcein-AM; 5μM), imaged (Zeiss CLSM510) and volumes determined quantitatively as described (2). An acute osmotic challenge (280-140mOsm) was delivered by perfusion to determine volume-regulatory capacity by cells in the various zones.

Results: The resting volumes of proliferative and hypertrophic cells were 550±63μm3 and 5227±1974μm3 respectively. Reducing osmolarity resulted in a rapid (within ~1min) cell swelling, proliferative and hypertrophic chondrocytes increasing in volume by 126±2% and 146±5% (n=5) respectively. Chondrocytes within the proliferative zone then recovered in volume by ~60% over the following 20mins (p=0.04), whereas no volume recovery was detected in hypertrophic cells (p=0.94).

Conclusions: For the increase in growth plate chondrocyte volume to produce hypertrophy it is essential that the membrane transporters which normally prevent cell swelling are suppressed, otherwise the increase in volume will be compromised. These results suggest that chondrocyte hypertrophy is associated with reduced activity of the swelling-stimulated osmolyte transporter whereas the pathway is active in proliferating chondrocytes. Changes in the activity of this pathway are likely to be an important component in the control of chondrocyte hypertrophy. It is clear that the contributions of other membrane transporters in mediating chondrocyte swelling must be identified in order to understand the overall hypertrophic process.