James S Huntley

Chondrocyte death associated with human femoral osteochondral harvest as performed for mosaicplasty

BACKGROUND Autologous osteochondral transfer is an option for the treatment of articular defects. However, there are concerns about graft integration and the nature of the tissue forming the cartilage-cartilage bridge. Chondrocyte viability at graft and recipient edges is thought to be an important determinant of the quality of repair. The purpose of the present study was to evaluate early cell viability at the edges of osteochondral grafts from ex vivo human femoral condyles. METHODS Fresh human tissue was obtained from eleven knees at the time of total knee arthroplasty for the treatment of osteoarthritis. Osteochondral cylinders were harvested with use of a 4.5-mm-diameter mosaicplasty osteotome from regions of the anterolateral aspect of the femoral condyle that were macroscopically nondegenerate and histologically nonfibrillated. Plugs were assessed for marginal cell viability by means of confocal laser scanning microscopy. RESULTS The diameter of the cartilaginous portion of the osteochondral plugs was a mean (and standard error of the mean) of 4.84 +/- 0.12 mm (as determined on the basis of three plugs). This value was approximately 300 microm greater than the measured internal diameter of the osteotome. There was a substantial margin of superficial zone cell death (mean thickness, 382 +/- 68.2 microm), with >99% cell viability seen more centrally (as determined on the basis of five plugs). Demiplugs were created by splitting the mosaicplasty explants with a fresh number-11 scalpel blade. The margin of superficial zone cell death at the curved edge was significantly greater than that at the site of the scalpel cut (390.3 +/- 18.8 microm compared with 34.8 +/- 3.2 microm; p = 0.0286). Similar findings were observed when the cartilage alone was breached and the bone was left intact, with the margin of superficial zone cell death being significantly greater than that obtained in association with the straight scalpel incision (268 +/- 38.9 microm compared with 41.3 +/- 13.4 microm; p = 0.0286). The margin of superficial zone cell death showed no increase during the time-period between fifteen minutes and two hours after plug harvest. A mathematical approximation of the mosaicplasty region suggested that early cell death of this magnitude affects about one third of the superficial graft area. CONCLUSIONS The results of the present study suggest that mosaicplasty, while capable of transposing viable hyaline cartilage, is associated with an extensive margin of cell death that is likely to compromise lateral integration and articular reconstruction.

Osmolarity influences chondrocyte death in wounded articular cartilage

BACKGROUND Mechanical injury results in chondrocyte death in articular cartilage. The purpose of the present study was to determine whether medium osmolarity affects chondrocyte death in injured articular cartilage. METHODS Osteochondral explants (n = 48) that had been harvested from the metacarpophalangeal joints of three-year-old cows were exposed to media with varying osmolarity (0 to 480 mOsm) for ninety seconds to allow in situ chondrocytes to respond to the altered osmotic environment. Explants were then wounded with a scalpel through the full thickness of articular cartilage, incubated in the same media for 2.5 hours, and transferred to 340-mOsm Dulbeccos Modified Eagle Medium (control medium) with further incubation for seven days. The spatial distribution of in situ chondrocyte death, percentage cell death, and marginal cell death at the wounded cartilage edge were compared as a function of osmolarity and time (2.5 hours compared with seven days) with use of confocal laser scanning microscopy. RESULTS In situ chondrocyte death was mainly localized to the superficial tangential zone of injured articular cartilage for the range of medium osmolarities (0 to 480 mOsm) at 2.5 hours and seven days. Therefore, a sample of articular cartilage from the superficial region (which included the scalpel-wounded cartilage edge) was studied with use of confocal laser scanning microscopy to compare the effects of osmolarity on percentage and marginal cell death in the superficial tangential zone. Compared with the control explants exposed to 340-mOsm Dulbeccos Modified Eagle Medium, percentage cell death in the superficial tangential zone was greatest for explants exposed to 0-mOsm (distilled water) and least for explants exposed to 480-mOsm Dulbeccos Modified Eagle Medium at 2.5 hours (13.0% at 340 mOsm [control], 35.5% at 0 mOsm, and 4.3% at 480 mOsm; p <or= 0.02 for paired comparisons) and seven days (9.9% at 340 mOsm [control], 37.7% at 0 mOsm, and 3.5% at 480 mOsm; p <or= 0.01 for paired comparisons). Marginal cell death in the superficial tangential zone decreased with increasing medium osmolarity at 2.5 hours (p = 0.001) and seven days (p = 0.002). There was no significant change in percentage cell death from 2.5 hours to seven days for explants initially exposed to any of the medium osmolarities. CONCLUSIONS Medium osmolarity significantly affects chondrocyte death in wounded articular cartilage. The greatest chondrocyte death occurs at 0 mOsm. Conversely, increased medium osmolarity (480 mOsm) is chondroprotective. The majority of cell death occurs within 2.5 hours, with no significant increase over seven days.

Rapid prototyping in orthopaedic surgery: a user's guide

Rapid prototyping (RP) is applicable to orthopaedic problems involving three dimensions, particularly fractures, deformities, and reconstruction. In the past, RP has been hampered by cost and difficulties accessing the appropriate expertise. Here we outline the history of rapid prototyping and furthermore a process using open-source software to produce a high fidelity physical model from CT data. This greatly mitigates the expense associated with the technique, allowing surgeons to produce precise models for preoperative planning and procedure rehearsal. We describe the method with an illustrative case.

Chondrocyte Death in Mechanically Injured Articular Cartilage―The Influence of Extracellular Calcium

Calcium is thought to be an important regulator of chondrocyte death associated with articular cartilage injury. Our objective was to determine the influence of extracellular calcium on chondrocyte death following mechanical injury. Using a surgically relevant model of sharp mechanical injury (with a scalpel) and confocal laser scanning microscopy (CLSM), in situ chondrocyte death was quantified within the full thickness of articular cartilage as a function of medium calcium concentration and time (2.5 h and 7 days). Exposure of articular cartilage to calcium‐free media (∼0 mM) significantly reduced superficial zone chondrocyte death after mechanical injury compared with exposure to calcium‐rich media (2–20 mM, ANOVA at 2.5 h, p = 0.002). In calcium‐rich media, although the extent of chondrocyte death increased with increasing medium calcium concentration, cell death remained localized to the superficial zone of articular cartilage over 7 days (ANOVA, p < 0.05). However, in calcium‐free media, there was an increase in chondrocyte death within deeper zones of articular cartilage over 7 days. The early (within hours) chondroprotective effect in calcium‐free media suggests that the use of joint irrigation solutions without added calcium may decrease chondrocyte death from mechanical injury during articular surgery. The delayed (within days) increase in chondrocyte death in calcium‐free media supports the use of calcium supplementation in media used during cartilage culture for tissue engineering or transplantation.

Attitudes towards alcohol of emergency department doctors trained in the detection of alcohol misuse.

INTRODUCTION Alcohol misuse creates an immense burden for society, with problem drinkers too often constituting a neglected group. The Paddington Alcohol Test (PAT) is a useful screening tool in emergency departments. METHODS Using a questionnaire, we assessed the attitudes of 127 emergency department junior doctors over 5 years to misuse detection using the PAT, in a centre with a well-defined protocol for detection and referral. RESULTS The majority (99%) thought early detection important, and the emergency department an appropriate place for screening (98%). Most thought that treatment could be successful (98%), and the PAT a useful instrument for early detection (87%). However, 63% reported that they misuse alcohol at least once a month and 30% once or more a week. DISCUSSION AND CONCLUSIONS Junior doctors trained in the detection of alcohol misuse have a very positive view of this work. However, this professional insight is in marked contrast to their personal misuse of alcohol. This paradox reflects the entrenched culture of alcohol use in the medical profession, perhaps learnt at medical school.

Hyperosmolarity protects chondrocytes from mechanical injury in human articular cartilage

The aim of this study was to determine whether exposure of human articular cartilage to hyperosmotic saline (0.9%, 600 mOsm) reduces in situ chondrocyte death following a standardised mechanical injury produced by a scalpel cut compared with the same assault and exposure to normal saline (0.9%, 285 mOsm). Human cartilage explants were exposed to normal (control) and hyperosmotic 0.9% saline solutions for five minutes before the mechanical injury to allow in situ chondrocytes to respond to the altered osmotic environment, and incubated for a further 2.5 hours in the same solutions following the mechanical injury. Using confocal laser scanning microscopy, we identified a sixfold (p = 0.04) decrease in chondrocyte death following mechanical injury in the superficial zone of human articular cartilage exposed to hyperosmotic saline compared with normal saline. These data suggest that increasing the osmolarity of joint irrigation solutions used during open and arthroscopic articular surgery may reduce chondrocyte death from surgical injury and could promote integrative cartilage repair.

C-reactive protein: a valuable acute investigation. A case of pneumococcal meningitis presenting as ankle pain

A case is presented in which the decision to admit and treat an adult with musculoskeletal pain and pyrexia was based on her markedly raised c-reactive protein (CRP). At the time of admission she was apyrexial and the CRP was the only haematological investigation that was out of the normal range. She subsequently became precipitously septic with pneumococcal bacteraemia and meningitis. The CRP is an important investigation for emergency departments.

Tensioning of Prolene reduces creep under cyclical load: relevance to a simple pre-operative manoeuvre

A longitudinal stretch or ‘pre-tensioning’ is a method employed by some surgeons to improve the handling characteristics of a suture. We used a tensile tester to assess the effect of pre-tensioning on the mechanical properties of two suture materials (3-0 Prolene and 3-0 Ethibond) commonly used for flexor tendon repair. A cyclical loading programme was used to simulate an early rehabilitation regime. All sutures were subsequently tested to failure (for ultimate tensile strength). The pre-tensioned Prolene sutures showed significantly less creep after cyclical loading in comparison to controls. Conversely pre-tensioning had no measurable effect on the deformation of Ethibond by creep. There was no effect on ultimate tensile strength for either material. The propensity of Prolene to creep (and thereby form a ‘gap’ in tendon repairs) can be reduced by pre-tensioning.

Neurological status in paediatric upper limb injuries in the emergency department – current practice

BackgroundIn upper limb injuries it is important to assess associated neurological injury. The aim of this study was to assess the initial (Emergency Department (ED)) documentation of neurological status in paediatric patients presenting with upper limb injuries.FindingsCase notes of paediatric patients admitted to the orthopaedic ward with upper limb injuries were retrospectively collected over a three month period. Initial ED documentation was recorded and case notes examined for any neurological deficit on admission. Of the 121 patients, 107 (88.4%) of case notes had some form of neurological documentation. The remaining case notes (n = 14, 11.6%) had no mention of neurological examination. There were 10 (8.2%) patients with pre-operative neurological deficits identified; none of these had been previously identified by the ED.ConclusionThere are failings of neurological documentation on the part of ED staff. It is likely that these reflect a knowledge deficit in the examination of the injured upper limb in paediatric patients.

The Rate of Skeletal Maturation in the Scottish Population : A Comparison Across 25 Years (1980-2005)

Background: A retrospective, cross-sectional study was performed to compare the rates of skeletal maturation in Scottish populations 25 years apart (1980-2005). Methods: Two cohorts of sequentially radiographs were identified from patients at a Scottish pediatric hospital in 1980 and 2005. All radiographs were performed after trauma. The bone age was measured according to the Carpal scoring system of the Tanner-Whitehouse 2 method. Results: One hundred four and 103 radiographs were included from 1980 and 2005, respectively. The radiographs from 2005 showed the children to have achieved older bone ages for given chronological ages than in 1980 (P < 0.0001). Conclusions: The findings have an important implication for the management of children with limb-length discrepancy. Children may not have the growth potential anticipated by chronological age; this will affect the timing of surgery and medical treatment of abnormalities of puberty and stature. Level Evidence: Level III.