Does intervertebral disc degeneration in adolescent idiopathic scoliosis correlate with patient-reported pain scores? A review of 968 cases.

PURPOSE: Report the rate and severity of degenerative disc disease (DDD) in non-surgical adolescent idiopathic scoliosis (AIS) patients and correlate these findings with patient-reported symptomatology scores. Additionally, to quantify the rate of concurrent pathological radiological findings in this group. METHODS: This was a retrospective chart review study at a single tertiary centre. AIS patients aged 10-16 who had received a whole spine MRI between September 2007 and January 2019 and who had not received surgical intervention to their spine were included. MRI scan reports were screened to extract those who had evidence of DDD. These were then reviewed by a blinded second reviewer who graded every disc using the Pfirrmann grading system. SRS-22 scores were extracted for patients when available. RESULTS: In total, 968 participants were included in the study. Of these, 93 (9.6%) had evidence of DDD, which was Pfirrmann grade ≥ 3 in 28 (2.9%). The most commonly affected level was L5/S1 (59.1% of DDD cases). A total of 55 patients (5.7%) had evidence of syringomyelia, 41 (3.4%) had evidence of spondylolisthesis (all L5/S1), 14 (1.4%) had bilateral L5 pars defects, and 5 (0.5%) had facet joint degeneration. Spondylolisthesis and bilateral pars defects were more common in patients with DDD identified on MRI scan (p < 0.001 and p = 0.04, respectively). Function (p = 0.048) and pain (p = 0.046) scores were worse in patients with DDD. CONCLUSION: We present a baseline for the rate and severity of DDD in the non-operative AIS cohort. This should assist in decision-making and counselling of patients prior to surgery. LEVEL OF EVIDENCE: III.

Systematic Review and Meta-analysis: Does Anterior-Posterior Spinal Fusion Still have a Role in Severe Thoracic Adolescent Idiopathic Scoliosis?

Background: Debate exists as to whether anterior-posterior spinal fusion (APSF), rather than posterior-only spinal fusion (PSF), provides benefit for treating severe thoracic adolescent idiopathic scoliosis (AIS). This systematic review and meta-analysis compare (1) Cobb angle correction, (2) complication and reoperation rate, (3) pulmonary function, (4) number of fused segments, and 5) patient-reported outcome measures (PROMs) in both groups. Methods: Electronic databases were searched to identify studies that met the following inclusion criteria: comparative studies (level 3 or above), severe thoracic curves (≥ 70°), age ≤ 16, AIS aetiology, Lenke 1-4 curves and follow-up ≥ 1 year for ≥ 95% of patient population. Literature was graded for quality and bias using GRADE and MINORS criteria. Results: Eight studies were included, defined by GRADE as low or moderate level evidence. Three studies showed superior curve correction in the APSF group; however, the meta-analysis showed no significant difference in curve correction between groups (95% CI - 3.45-12.96, P = 0.26). There were more complications in the APSF group, without statistical significance (95% CI 0.53-3.39, P = 0.54; I 2 = 0%, P = 0.78). There were no re-operations in either group. Two studies reported pulmonary function; one showed better function in the APSF group, the other better function in the PSF group. One study showed fewer fused segments in the APSF group, however, no significance was observed in the meta-analysis (95%CI - 1.65-0.31, P = 0.18). Three studies reported PROMs with no differences reported between groups. Conclusions: APSF and PSF have been found to have comparable results. The present evidence cannot support recommendations for guidelines on future practice with regards to effect on curve correction, complications, re-operations, pulmonary function or PROMs. Level of evidence: Level III, Systematic review of Level-III studies.

Patient-specific 3D printing to replace components of a rib-to pelvis "Eiffel Tower" vertebral expanding prosthetic titanium rib system in an infant: a case report.

PURPOSE: To address the anatomical challenges facing complex and revision spinal surgery, patient-specific 3D-printed models (3D-PMs) have received growing attention worldwide, primarily in adults. We report the use of a 3D-PM in the treatment of a case of wound breakdown over a component of a VEPTR (Vertical Expandable Prosthetic Titanium Rib; DePuy-Synthes) system, requiring replacement of Dunn-McCarthy hook and sleeve with components contoured to a patient-specific 3D-PM of the spine. METHOD: A two-year-old born with myelomeningocele (MMC), repaired at birth, developed progressive MMC-associated kyphoscoliosis. Elective insertion of a rib-to-pelvis 'Eiffel Tower' bilateral VEPTR growing rods construct was performed without initial complication. Prominence of the right VEPTR sleeve and Dunn-McCarthy hook side-to-side connector resulted in breakdown of overlying poor-quality soft tissues, necessitating washout, partial implant removal, intravenous antibiotic therapy and delayed primary wound closure. A patient-specific 3D-PM, utilising pre-operative CT spine and pelvis 3D-reconstructions, allowed pre-operative formation of a contoured implant, which was inserted without need for further revision. RESULTS: The patient underwent further VEPTR lengthening without recurrent infection, wound breakdown or implant failure at 24-month follow-up. Satisfactory control of the deformity has been achieved with continued improvement in sitting height and radiographic indices. CONCLUSION: This case illustrates the possibility, in certain cases, of using 3D-PM to develop complex components of spinal implant systems pre-operatively, removing the time and difficulty of intra-operative contouring. Consequently, custom-contoured implants may be produced, sterilised and implanted. This technique may be an option, in infants, including MMC-associated kyphoscoliosis, where midline fixation is not possible.

e-Cigarette Vapour Condensate Reduces Viability and Impairs Function of Human Osteoblasts, in Part, via a Nicotine Dependent Mechanism.

Cigarette consumption negatively impacts bone quality and is a risk-factor for the development of multiple bone associated disorders, due to the highly vascularised structure of bone being exposed to systemic factors. However, the impact on bone to electronic cigarette (e-cigarette) use, which contains high doses of nicotine and other compounds including flavouring chemicals, metal particulates and carbonyls, is poorly understood. Here, we present the first evidence demonstrating the impact of e-cigarette vapour condensate (replicating changes in e-cigarette liquid chemical structure that occur upon device usage), on human primary osteoblast viability and function. 24 h exposure of osteoblasts to e-cigarette vapour condensate, generated from either second or third generation devices, significantly reduced osteoblast viability in a dose dependent manner, with condensate generated from the more powerful third generation device having greater toxicity. This effect was mediated in-part by nicotine, since exposure to nicotine-free condensate of an equal concentration had a less toxic effect. The detrimental effect of e-cigarette vapour condensate on osteoblast viability was rescued by co-treatment with the antioxidant N-Acetyl-L-cysteine (NAC), indicating toxicity may also be driven by reactive species generated upon device usage. Finally, non-toxic doses of either second or third generation condensate significantly blunted osteoblast osteoprotegerin secretion after 24 h, which was sustained for up to 7 days. In summary we demonstrate that e-cigarette vapour condensate, generated from commonly used second and third generation devices, can significantly reduce osteoblast viability and impair osteoblast function, at physiologically relevant doses. These data highlight the need for further investigation to inform users of the potential risks of e-cigarette use on bone health, including, accelerating bone associated disease progression, impacting skeletal development in younger users and to advise patients following orthopaedic surgery, dental surgery, or injury to maximise bone healing.

The impact of E-cigarette vaping and vapour constituents on bone health.

BACKGROUND: In contrast to cigarettes, electronic cigarette use (E-cigarettes) has grown substantially over the last decade. This is due to their promotion as both a safer alternative to cigarettes and as an aide to stop smoking. Critically, upon E-cigarette use, the user may be exposed to high doses of nicotine in addition to other compounds including flavouring chemicals, metal particulates and carbonyl compounds, particularly in highly vascularised tissues such as bone. However, there has been limited investigation into the impact of E-cigarette usage on bone physiology, particularly over extended time periods and there are no clinical recommendations regarding E-cigarette usage in relation to orthopaedic surgery. This literature review draws together data from studies that have investigated the impact of E-cigarette vapour and its major constituents on bone, detailing the models utilised and the relevant mechanistic and functional results. MAIN BODY: Currently there is a lack of studies both in vivo and in vitro that have utilised E-cigarette vapour, necessary to account for changes in chemical composition of E-cigarette liquids upon vaping. There is however evidence that human bone and bone cells express nicotine receptors and exposure of both osteoblasts and osteoclasts to nicotine, in high concentrations may reduce their viability and impair function. Similarly, it appears that aldehydes and flavouring chemicals may also negatively impact osteoblast viability and their ability to form bone. However, such functional findings are predominantly the result of studies utilising bone cell lines such as MG-63 or Saos-2 cells, with limited use of human osteoblasts or osteoclasts. Additionally, there is limited consideration for a possible impact on mesenchymal stem cells, which can also play an import role in bone repair. CONCLUSION: Understanding the function and mechanism of action of the various components of E-cigarette vapour in mediating human bone cell function, in addition to long term studies to determine the potential harm of chronic E-cigarette use on human bone will be important to inform users of potential risks, particularly regarding bone healing following orthopaedic surgery and injury.

Index radiographic measurements in the prediction of progression in infantile idiopathic scoliosis: a comparative analysis and description of a novel predictive model.

PURPOSE: To assess the comparative accuracy of commonly utilised index radiological measurements in the prognosis of infantile idiopathic scoliosis (IIS) and build a parsimonious prognostic model utilising these measurements. METHODS: This was a retrospective analysis of a UK population of patients with IIS. Index radiological parameters were analysed, and outcome of their condition was determined over long-term follow-up. Comparative accuracy of each radiological measurement category was determined by logistic regression analyses and the corresponding receiver operating characteristic (ROC) curve. A predictive model of IIS progression using these measurements was then created. RESULTS: All three radiological measurement categories were predictive of IIS progression. However, on pairwise comparison of ROC curves and multivariate analysis, the index Cobb angle proved the most significant predictor of curve progression. Using the index Cobb angle only, a predictive model of curve progression achieved an accuracy of 81.18% with a cut-off Cobb angle of 34.5° found to be the optimal threshold to discriminate a progressive from resolving curve. CONCLUSION: Of the three analysed index radiological parameters commonly used by surgeons in the prognosis of IIS, we found that the Cobb angle is the most accurate predictive measure. Further, neither addition of the RVAD nor convex RVA provided significant further prognostic value in a multivariate model of progression. However, not even the Cobb angle model was accurate in all cases; emphasising caution should be applied when relying on index radiological measurements to predict IIS outcomes.

Efficacy of distal pedicle screw fixation as a caudal foundation in VEPTR growing rod constructs for early onset scoliosis.

PURPOSE: Surgical treatment of Early Onset Scoliosis (EOS) is challenging. Stable and robust foundations are vital. We have assessed a small cohort of patients with a rib-based proximal fixation and a pedicle screw-based distal foundation for a distraction based growing rod system. METHOD: This is a single center study in a tertiary spinal deformity unit with a catchment population of over 6 million. We performed a retrospective radiographic evaluation of 15 patients with EOS treated with Vertical Expandable Titanium Prosthetic Rib (VEPTR) implant between 2007 and 2017. The review of medical records and imaging data was performed to identify growth of the spine and complications with pedicle screws. RESULTS: There were ten male and five female patients with an average age at index surgery of 4yrs 11 months. Mean length of follow-up was 6 yrs 9 months. Serial radiographs revealed improvements in mean Cobb angle of 12 degrees, T1-T12 height of 29 mm and T1-S1 height of 48 mm with no deterioration in distal LIV tilt angle. We report that none of these patients had any complications related to their pedicle screws including cut-out. CONCLUSION: We report a technique which is efficacious and provides a mechanically robust distal fixation for VEPTR lengthening in early onset scoliosis.

Long-term follow-up of patients with infantile idiopathic scoliosis: is the rib vertebra angle difference (RVAD) a reliable indicator of evolution?

PURPOSE: Since its original description by Mehta, the rib vertebra angle difference (RVAD) and, in particular, a threshold of 20° have become an accepted and widely utilised prognostic indicator in the assessment of patients presenting with an infantile idiopathic scoliosis (IIS). However, uncertainty in the utility of the RVAD in the prognosis of IIS remains. The aims of this study were to investigate the prognostic significance of the RVAD and to describe the changes in RVAD over long-term follow-up of patients with progressive and resolving IIS. METHODS: This was a retrospective analysis of patients presenting with IIS at a tertiary spinal deformity unit in the UK. Serial patient radiographs were reviewed and a logistic regression model using the patients index RVAD was created to predict the likelihood of curve progression. RESULTS: At both index presentation and over long-term follow-up, patients with a progressive curve had significantly greater mean Cobb angle and RVAD measurements than those with resolving curves. The RVAD and Cobb were found to correlate positively in both groups, reflecting the underlying costovertebral pathoanatomy. The logistic regression model demonstrated that the optimal RVAD threshold in predicting IIS progression was lower at 17.1° than the 20° cut-off previously advocated. CONCLUSION: This study describes the utility of the RVAD in predicting IIS evolution. From this analysis, we would advise caution in predicting outcomes based on the index RVAD at presentation. LEVEL OF EVIDENCE: II.

Evidence of Intrinsic Impairment of Osteoblast Phenotype at the Curve Apex in Girls With Adolescent Idiopathic Scoliosis.

STUDY DESIGN: An observational descriptive study based on a single cohort of patients. OBJECTIVE: To determine whether spinal facet osteoblasts at the curve apex display a different phenotype to osteoblasts from outside the curve in adolescent idiopathic scoliosis (AIS) patients. SUMMARY OF BACKGROUND DATA: Intrinsic differences in the phenotype of spinal facet bone tissue and in spinal osteoblasts have been implicated in the pathology of AIS. However, no study has compared the phenotype of facet osteoblasts at the curve apex compared with outside the curve in AIS patients. METHODS: Facet spinal tissue was collected perioperatively from three sites, the concave and convex side at the curve apex and from outside the curve (noncurve) from three AIS female patients aged 13-16 years. Spinal tissue was analyzed by micro-computed tomography to determine bone mineral density (BMD) and trabecular structure. Primary osteoblasts were cultured from concave, convex, and noncurve facet bone chips. The phenotype of osteoblasts was determined by assessment of cellular proliferation, cellular metabolism (alkaline phosphatase and Seahorse Analyzer), bone nodule mineralization (Alizarin red assay), and the mRNA expression of Wnt signaling genes (quantitative reverse transcriptase polymerase chain reaction). RESULTS: Convex facet tissue exhibited greater BMD and trabecular thickness, compared with concave facet tissue. Osteoblasts at the convex side of the curve apex exhibited a significantly higher proliferative and metabolic phenotype and a greater capacity to form mineralized bone nodules, compared with concave osteoblasts. mRNA expression of SKP2 was significantly greater in both concave and convex osteoblasts, compared with noncurve osteoblasts. The expression of SFRP1 was significantly downregulated in convex osteoblasts, compared with either concave or noncurve. CONCLUSIONS: Intrinsic differences that affect osteoblast function are exhibited by spinal facet osteoblasts at the curve apex in AIS patients. LEVEL OF EVIDENCE: Level IV, Prognostic.

Is the routine use of magnetic resonance imaging indicated in patients with scoliosis?

BACKGROUND: To assess the reliability of the indicators for performing magnetic resonance imaging in patients with scoliosis and assess the incidence of neural axis anomalies in a population with scoliosis referred to a specialist centre. METHODS: A retrospective review of magnetic resonance imaging (MRI) reports of all patients under the age of 18 who underwent a pre-operative MRI for investigation of their scoliosis between 2009 and 2014 at a single institution was performed. RESULTS: There were 851 patients who underwent an MRI scan of their whole spine with a mean age of 14.08 years. There were 211 males and 640 females. One hundred and fourteen neural axis abnormalities (NAA) were identified. The presence of a left sided thoracic curve, a double thoracic curve, being male nor being diagnosed before the age of 10 were found to be statistically significant for the presence of a NAA. Furthermore, 2.34% of patients were also found to have an incidental finding (IF) of an extraspinal abnormality. CONCLUSIONS: From our series, the reported indications for performing an MRI scan in the presence of scoliosis are not reliable for the presence of an underlying NAA. We have demonstrated that there is a number of intra and extra dural anomalies found on MRI without clinical symptoms and signs. This acts as normative information for this group. KEYWORDS: Scoliosis; magnetic resonance imaging (MRI); neural axis abnormalities (NAA); adolescent idiopathic scoliosis (AIS).

Magnetically Controlled Growing Rods: The Experience of Mechanical Failure from a Single Center Consecutive Series of 28 Children with a Minimum Follow-up of 2 Years.

STUDY DESIGN: Retrospective observational study of a continuous series of 28 children. PURPOSE: To determine the mechanical failure rate in our cohort of children treated with magnetically controlled growth rods (MCGRs). OVERVIEW OF LITERATURE: Previous studies report a MCGR mechanical failure rate of 0%-75%. METHODS: All patients with MCGR implantation between 2012 and 2015 were examined and followed up for a minimum of 2 years. A retrospective evaluation of contemporaneously documented clinical findings was conducted, and radiographs were retrospectively examined for mechanical failure. The external remote controller (ERC)-specified length achieved in the clinic was compared to the length measured on subsequent radiographs. RESULTS: Fourteen mechanical failures were identified in 28 children (50%) across a total of 52 rods (24 pairs and four single constructs). Mechanical failures were due to: failure to lengthen under general anesthesia (seven children), actuator pin fracture (four), rod fracture (one), foundation screw failure (one), and ran out of rod length (one). Of the 14 mechanical failures, six were treated with final fusion operations (reflecting limited further growth potential), and eight patients were treated with the intention for further lengthening. We therefore consider these eight patients to represent the true incidence of mechanical failure in our cohort (29%). The difference between the ERC length and radiographic length was found to be identical in 11% cases; 35% were overestimates, and 54% were underestimates. The median underestimate was 2.45 mm whereas the median overestimate was 3.1 mm per distraction episode. In total, 95% of all ERC distractions were within ±10 mm of the radiographic length achieved over a median of nine distraction episodes. CONCLUSIONS: Our series is the most comprehensive MCGR series published to date, and we present a mechanical failure rate of 29%. Clinicians should be mindful of the discrepancies between ERC length and radiographic measurements of rod length; other modalities may be more helpful in this regard.

The Effect of Vancomycin and Gentamicin Antibiotics on Human Osteoblast Proliferation, Metabolic Function, and Bone Mineralization.

STUDY DESIGN: The present study investigates the effect of vancomycin and gentamicin antibiotics on primary human osteoblasts. Osteoblasts were incubated with vancomycin, gentamicin, or with povidone-iodine (PVI), at concentrations advocated for wound irrigation. Osteoblast proliferation, metabolic function, and bone mineralization were measured. OBJECTIVE: The aim of the study was to model gentamicin and vancomycin wound irrigation in vitro and to examine the effect on osteoblast viability and cellular function in comparison to 0.35% PVI. SUMMARY OF BACKGROUND DATA: Vancomycin, gentamicin, and dilute PVI are employed as wound irrigants in spinal surgery to reduce infection. We have, however, recently demonstrated that 0.35% PVI has a detrimental effect on osteoblast cellular function and bone mineralization. Studies to determine the effects of antibiotic wound irrigation solutions on osteoblasts and bone mineralization are therefore warranted. METHODS: Primary human osteoblasts were exposed for 20 minutes to phosphate buffered saline (PBS) control, vancomycin (35 or 3.5 mmol/L), gentamicin (34 or 3.4 mmol/L), or 0.35% PVI for 3 minutes. Cellular proliferation was measured during 7 days by MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium) assay. Osteoblast metabolic function was determined using a Seahorse XFe24 Bioanalyzer. Mineralized bone nodules were quantified using Alizarin red. RESULTS: At concentrations advocated for wound irrigation, both gentamicin (3.4 mmol/L) and vancomycin (3.5 mmol/L) induced a transient 15% to 20% reduction in osteoblast proliferation, which returned to control values within 72 hours. This was in marked contrast to the effect of 0.35% PVI, which resulted in a sustained reduction in osteoblast proliferation of between 40% and 50% during 7 days. Neither gentamicin nor vancomycin at concentrations up to 10× clinical dose had any effect on osteoblast oxygen consumption rate, or significantly affected mineralized bone nodule formation. CONCLUSION: Vancomycin and gentamicin solutions, at concentrations advocated for intrawound application in spinal surgery, have a small but transient effect on osteoblast proliferation, and no effect on either osteoblast metabolic function or bone nodule mineralization. LEVEL OF EVIDENCE: N/A.

Does the law of diminishing returns apply to the lengthening of the MCGR rod in early onset scoliosis with reference to growth velocity?

BACKGROUND: This study is a single centre retrospective review of prospectively collected data. The 'law of diminishing returns' describes the number of lengthening episodes that a traditional growth rod (TGR) can undergo before stiffness across the construct prevents further increases in overall length. It is unclear whether this will affect MCGR when used in the management of early onset scoliosis (EOS). METHODS: A retrospective review of prospectively collected data on the experience of MCGR lengthening in a heterogenous cohort of children with EOS from a single centre. RESULTS: There were 53 MCGRs in 28 patients with EOS with a number of different underlying diagnoses. The mean age of the cohort was 8 years 3 months (SD, 2 years 7 months). The mean follow-up period since primary rod implantation was 2 years 0 months (SD, 1 year 1 month). MCGR lengthening was performed on up to 12 occasions [median, 4; interquartile range (IQR), 4; range, 1-12]. There was no statistically significant difference in the amount of length achieved over then number of lengthening episodes (P=0.427). For those with at least 2 years follow up the median number of lengthening was 10 (IQR 2, range 9-12) and there was no statistically significant difference seen (P=0.438). Growth velocity of MCGRs against age was less than previously documented norms for the thoracic spine, but was maintained as age increased. CONCLUSIONS: The 'law of diminishing returns' does not affect serial lengthening of MCGR in the way that has been observed using TGR. It was also demonstrated that in the MCGR group growth velocity was maintained relative to that of the normal spine.

Adolescent idiopathic scoliosis: evidence for intrinsic factors driving aetiology and progression.

Adolescent idiopathic scoliosis (AIS) is now considered to be a multifactorial heterogeneous disease, with recent genomic studies supporting the role of intrinsic factors in contributing to the onset of disease pathology and curve progression. Understanding the key molecular signalling pathways by which these intrinsic factors mediate AIS pathology may facilitate the development of pharmacological therapeutics and the identification of predictive markers of progression. The heterogenic nature of AIS has implicated multiple tissue types in the disease pathophysiology, including spinal bone, intervertebral disc and paraspinal muscles. In this review, we highlight some of the mechanisms and intrinsic molecular regulators within these different tissue types and review the evidence for their involvement in AIS pathology.

Povidone-Iodine Has a Profound Effect on In Vitro Osteoblast Proliferation and Metabolic Function and Inhibits Their Ability to Mineralize and Form Bone.

STUDY DESIGN: A study examining the clinical protocol of scoliosis wound irrigation, demonstrating povidone-iodine's (PVI) effect on human osteoblast cells. Primary and immortal cell line osteoblasts were treated with 0.35% PVI for 3 minutes, and analyzed for proliferation rate, oxidative capacity, and mineralization. OBJECTIVE: To model spinal wound irrigation with dilute PVI in vitro, in order to investigate the effect of PVI on osteoblast proliferation, metabolism, and bone mineralization. SUMMARY OF BACKGROUND DATA: Previously PVI irrigation has been proposed as a safe and effective practice to avoid bacterial growth after spinal surgery. However, recent evidence in multiple cell types suggests that PVI has a deleterious effect on cellular viability and cellular function. METHODS: Primary and immortal human osteoblast cells were exposed to either phosphate buffered saline control or with 0.35% PVI for 3 minutes. Cellular proliferation was measured over the duration of 7 days by MTS assay. Oxygen consumption rate, extracellular acidification rate, and proton production rate were analyzed using a Seahorse XF24 Bioanalyzer. Protein expression of the electron transport chain subunits CII-SDHB, CIII-UQRCR2, and CV-ATP5A was measured via Western blotting. Mineralized bone nodules were stained with alizarin red. RESULTS: Expressed as a percentage of normal osteoblast proliferation, osteoblasts exposed to 0.35% PVI exhibited a significant 24% decrease in proliferation after 24 hours. This was a sustained response, resulting in a 72% decline in cellular proliferation at 1 week. There was a significant reduction in oxygen consumption rate, extracellular acidification rate, and proton production rate (P < 0.05), in osteoblasts that had been exposed to 0.35% PVI for 3 minutes, coupled with a marked reduction in the protein expression of CII-SDHB. Osteoblasts exposed to 0.35% PVI exhibited reduced bone nodule mineralization compared to control phosphate buffered saline exposed osteoblasts (P < 0.01). CONCLUSION: PVI has a rapid and detrimental effect on human osteoblast cellular proliferation, metabolic function, and bone nodule mineralization. LEVEL OF EVIDENCE: NA.

The challenges of cartilage repair and the potential of stem cell applications.

Articular cartilage injuries pose a treatment challenge. These injuries are a direct cause of pain and loss of function and may precipitate osteoarthritis in the affected joint. Typically affecting a younger, more active population whose expectations of treatment and need for long term joint preservation are high. Articular cartilage poses a treatment challenge in that its capacity for satisfactory healing is limited. The common endpoint of conservative management and traditional surgical interventions is the generation of biomechanically inferior fibrocartilage. Regenerative techniques using human stem cells would appear to represent an exciting modality for the production of true hyaline cartilage with material and biological properties suited for lasting function. This review article summarises the current research regarding the use of human stem cells in the treatment of such injuries.