Autologous osteochondral grafting has demonstrated positive outcomes for treating articular cartilage defects by replacing the damaged region with a cylindrical graft consisting of bone with a layer of cartilage, taken from a non-loadbearing region of the knee. Despite positive clinical use, factors that cause graft subsidence or poor integration are relatively unknown. The aim of this study was to develop finite element (FE) models of osteochondral grafts within a tibiofemoral joint and to investigate parameters affecting osteochondral graft stability.

Initial experimental tests on cadaveric femurs were performed to calibrate the bone properties and graft-bone frictional forces for use in corresponding FE models, generated from µCT scan data. The effects of cartilage defects and osteochondral graft repair were measured by examining contact pressure changes using in vitro tests on a single cadaveric human tibiofemoral joint. Six defects were created in the femoral condyles which were subsequently treated with osteochondral autografts or metal pins. Matching µCT scan-based FE models were created, and the contact patches were compared. Sensitivity to graft bone properties was investigated.

The bone material properties and graft-bone frictional forces were successfully calibrated from the initial tests with good resulting levels of agreement (CCC=0.87). The tibiofemoral joint experiment provided a range of cases to model. These cases were well captured experimentally and represented accurately in the FE models. Graft properties relative to host bone had large effects on immediate graft stability despite limited changes to resultant cartilage contact pressure.

Model confidence was built through extensive validation and sensitivity testing, and demonstrated that specimen-specific properties were required to accurately represent graft behaviour. The results indicate that graft bone properties affect the immediate stability, which is important for the selection of allografts and design of future synthetic grafts.

Abstract

Abstract

Introduction Chicken studies implicate pinealectomy within a week of hatching as a cause of scoliosis. The nature of the scoliosis has been demonstrated to be similar to that of human idiopathic scoliosis. Scoliosis was not induced following pinealectomy in Rhesus monkeys (primate model). No human studies have been reported. The aim of this study is to determine if idiopathic scoliosis is associated with treatment for pineal lesions (presumably resulting in pinealectomy) in a human paediatric population.

Methods A medical records search was performed in five Australian States for pineal lesions. Identified patients underwent clinical or radiological evaluation for scoliosis. Pathology varied from germ cell tumour, germinoma, pineoblastoma, teratoma to a pineal cyst and an epidermoid cyst. Treatment ranged from biopsy/ extirpation to radiotherapy/chemotherapy.

Results Of 48 identified patients, thirteen are deceased. No scoliosis was present in the last imaging of the deceased. The mean age at presentation was 9.7 years (range 1–18 years). Ten are female. Two males have idiopathic scoliosis (4.2%). One has a 12° right upper thoracic curve (with 32° kyphosis) and the other has a 60° right thoracolumbar curve, requiring a two-stage arthrodesis

Discussion Although the incidence of idiopathic scoliosis in this cohort is greater than expected from Caucasian population studies (2–3%), it is not typical idiopathic-type, which has a female preponderance of larger deformities. New-born chicken studies demonstrate an incidence of between 50 and 100% scoliosis in the three months following pinealectomy. Chickens of both sexes are involved. Fundamental differences exist between chicken and human/primate models including the age at pinealectomy and the anatomical site of the pineal gland. Chickens have a naturally lordotic thoracic spinal curvature whilst humans/primates have a naturally kyphotic thoracic spine. Adolescents with idiopathic scoliosis have either thoracic hypokyphosis or a thoracic lordosis. Contrary to current beliefs, no causal link can be established between pineal lesions and the development of idiopathic scoliosis in a paediatric population.

Introduction Delayed puberty and delayed skeletal maturation have been implicated as risk factors for the progression of idiopathic scoliosis. Genetic defects (Turner syndrome) and hypothalamic- pituitary disorders are known causes of delayed puberty. Although it is recognized that the incidence of idiopathic scoliosis is elevated in Turner syndrome, human studies regarding the incidence/severity of scoliosis in children with suprasellar, hypothalamic region and pituitary tumours/ disorders is deficient.

Methods A medical records search in five Australian states for suprasellar, hypothalamic region and pituitary tumours/disorders was performed. Identified patients underwent clinical or radiological evaluation for scoliosis. Pathology varied from suprasellar-hypothalamic region tumours, pan-hypopituitarism, pituitary tumours and growth hormone deficiency as well as a craniopharyngioma, arachnoid cyst, retinoblastoma and encephalocele.

Results Of 23 identified patients, ten are female. Mean age at presentation was 8.4 years. Three have right thoracic scoliosis with a Cobb angle less than 20 degrees. Two are males; one with pituitary hormone deficiency and the other with Cushing’s disease treated with radiotherapy. The only female is on a growth hormone treatment program for idiopathic growth hormone deficiency.

Discussion The only female with scoliosis was 12 years old. Delayed puberty could not be linked to either male with scoliosis. Although the incidence of idiopathic scoliosis in this cohort is greater than expected from Caucasian population studies (2–3%), the male preponderance is unusual. No relationship between delayed skeletal maturation and idiopathic scoliosis could be established.

Introduction and Aims: SHOX haploinsufficiency presents with Turner syndrome dysmorphic skeletal features – micrognathia (60%), cubitus valgus (47%), high-arched palate (25%) and Madelung deformity (7%). Idiopathic scoliosis is also present in 11% of Turner syndrome. This clinical observation and radiological study explores the possibility of SHOX haploinsufficiency expression in the scoliotic spine in Turner syndrome.

Method: Turner syndrome presents a mesomelic short stature, thought to result from growth plate dysmorphism, presumably from SHOX gene haploinsufficiency. Forty-five Turner syndrome subjects on the Australian Growth Hormone program were clinically examined for the presence of idiopathic scoliosis. Of another 88 Turner syndrome subjects similarly examined, 46 had received growth hormone and 42 had never received growth hormone. Kosowicz (1959) and Preger (1968) noted irregular vertebral endplates of scoliotic spines in Turner syndrome subjects. This may imply dysmorphic vertebral growth plates. A spinal MRI and plain imaging study of idiopathic scoliosis with/without Turner syndrome was undertaken to examine for vertebral growth plate abnormalities.

Results: This study again demonstrates plain radiographic presence of irregular vertebral endplates of scoliotic spines in Turner syndrome. Spine MR imaging in Turner syndrome failed to clearly demonstrate the growth plates but demonstrated wedge-shaped distal vertebrae in the curve. Similar MR findings were noted in another 20 subjects with various causes of scoliosis. Wedged-shaped intervertebral discs were also noted, but are thought to be secondary changes. Of 87 Turner syndrome subjects from growth hormone programs, 18 (21%) were found to have idiopathic scoliosis. Thirteen of another 46 (28%) subjects who had never received growth hormone were also noted to have idiopathic scoliosis, indicating a combined incidence of 23%. These results contrast with Lippe (1991) and Kim (2001), who noted an incidence of 11% of 163 and 12% of 43 idiopathic scoliosis in Turner syndrome from retrospective observation. However, the incidence of scoliosis (41%) from the radiographic studies of Kosowicz (4/22) and Preger (19/34) is much greater than even the incidence noted clinically from this study.

Conclusion: SHOX haploinsufficiency expression is not yet described in Turner syndrome scoliotic spines, although it has been described in the distal radius (Munns, 2001) in Madelung deformity. The incidence of idiopathic scoliosis in Turner syndrome appears to be much larger than previously recognised, signalling a probable dysmorphic vertebral growth plate cause.

Introduction: Retrospective reports of adverse events following growth hormone administration to short-statured children indicate that the incidence of scoliosis is elevated, largely due to the higher incidence of scoliosis in Turner/other syndromes within the group. The aims of this study are to analyse risk factors for scoliosis in these children.

Methods: Data on 184 of 267 (65%) current and recent Australian children from the Australian OZGROW program was collected in 2001/2002 (from three Australian States). This included medical records (including past history of known scoliosis), growth charts, timing of growth hormone and oestrogen administration and the presence and severity of scoliosis from clinical examination. Growth hormone dosage was controlled by Australian Health Department guidelines. Standard oestrogen dosage was similar for all pubertal girls. The cohort was noted to comprise many varying syndromes, some of whom were pituitary hormone deficient. Potential risk factors for the development of scoliosis were statistically analysed.

Results: Of 45 subjects with Turner Syndrome, 13 (30%) have idiopathic scoliosis and 2 have a hemi-vertebra. Of the other 139 subjects, 15 have scoliosis but 11 have syndromes which would normally be associated with scoliosis. Therefore, the incidence of idiopathic scoliosis in the remaining 128 subjects is 3.1% (4/128), which is within the normal population range. All 4 have mild scoliosis < 20 degrees. For the 139 subjects with idiopathic short stature or a specific syndrome, the age of commencement and total amount of growth hormone and/or oestrogen did not affect the degree of scoliosis.

Discussion: Having Turner Syndrome was the only variable identified as a risk factor for having scoliosis (p< .001). The incidence of scoliosis in growth hormone treated Turner Syndrome subjects is much larger than previously reported (11–12%)^1,2. To the authors’ knowledge, this is the first report derived from non-retrospective data on the incidence of scoliosis in a growth hormone–treated Turner Syndrome population. This stimulated the next study looking at the incidence of scoliosis in growth hormone-treated and non-growth hormone-treated subjects with Turner Syndrome.

Introduction: Following an Australian study on the incidence of scoliosis in a population of short-statured children treated with human growth hormone (conducted during 2001–2002), it was determined that the only risk factor for the presence of idiopathic scoliosis was having Turner/another syndrome. The 30% incidence in Turner syndrome was noted to be much higher than previously reported (11–12%). The aim of this study is to determine the incidence of scoliosis in a group of growth hormone-treated and non-treated Turner Syndrome subjects who attended the International Turner Syndrome Society meeting in Sydney, Australia in July 2003 and to correlate the results with the Australian 2001–2002 results.

Methods: 88 subjects were clinically examined for the presence and severity of idiopathic scoliosis. Their ages ranged from 11 to 60 years. All subjects provided information regarding previous growth hormone and/or oestrogen administration. Anthropometric data including sitting and standing height and arm span was also collated on this cohort.

Results: 13 of 46 (28.3%) subjects who had no growth hormone treatment were found to have scoliosis. Five of 42 (12%) subjects who were growth hormone treated were found to have scoliosis. 12 curves were thoracic, five were thoracolumbar and one was lumbar. The 13 subjects with scoliosis and no growth hormone treatment had curves between10 and 20° Cobb angle. Three growth hormone-treated subjects had curves of 10°, one had a curve of 30° and the last subject had already undergone scoliosis surgery. Combining the results of this study with the three Australian States study from 2001–2002, 18 of 87 (21%) growth hormone-treated Turner syndrome subjects have idiopathic scoliosis. 13 of 46 (28%) non-growth hormone-treated Turner syndrome subjects also have idiopathic scoliosis. Of the total 133 subjects in this cohort, 31 (23%) have idiopathic scoliosis.

Discussion: The incidence of idiopathic scoliosis in Turner syndrome appears to have been understated in previous studies. Data from this study would indicate that treating children who have Turner syndrome with adjuvant human growth hormone does not appear to result in a greater incidence or severity of idiopathic scoliosis. In this relatively small study, two of five children who had previous growth hormone treatment developed larger curves, one requiring corrective scoliosis surgery.

Introduction: Patients with malignant spinal disease who have neurologic symptoms are often considered poor surgical candidates. The aim of this paper is to review the effect on neurologic symptoms of surgical management of malignant spinal disease.

Methods: A retrospective review of patients treated from January 1993 to June 2003 was undertaken. Pain status was assessed using patient statements and recorded analgesic requirements. Neurologic symptoms were assessed using Frankel’s grading.

Results: There were 95 patients (32 females aged 26–83; 63 males aged 15–89). No patients were asymptomatic. 61 of 109 presentations were with multiple symptoms. The most common symptom was pain (99) – either localised (8), non-specific back (56) and/or radicular (57). The next most frequent symptom was weakness (54). The time course of onset varied from acute ward deterioration, with urgent surgery, to slow progression over weeks, prior to elective surgery. 8 cases had sphincteric dysfunction.

There were 98 tumours treated. In females, the most common tumours were breast (8) and renal (4) and in males, prostate (13), multiple myeloma (12) and lung (10). The thoracic spine was involved in 62, the lumbar in 18, cervical in 16 and sacral in 2. The vertebral body was involved in 76.

There were 109 operations. An instrumented fusion was performed in 82. Surgical approach was anterior in 17 (9 cervical, 8 thoracic) and posterior in 80 (5 cervical, 56 thoracic and 17 lumbar). Six patients had combined approaches (2 cervical, 3 thoracic and 1 lumbar). Two patients were treated for metachronous tumours. One patient had non-contiguous metastases treated separately. One patient was treated for local recurrence. One patient had revision for implant failure (anterior thoracic). One patient was explored after deterioration due to loss of autoregulation. Thoraco-abdominal approaches (12) were associated with ileus (2) and pneumonia (3). Of four cases with deep wound infections, three had received prior local irradiation. Two patients died of pulmonary embolus. 83 patients survived beyond three months.

All patients demonstrated improvement in pain status. Thirteen of 29 non-ambulatory cases were able to mobilise postoperatively. There were 32 whose Frankel grades improved. Seventeen of these returned to normal (15 from Grade 4 and 2 from Grade 3). One patient with complete motor and sensory loss improved to useful but subnormal status, three others improved to residual motor function. 11 other patients improved one grade. Of those whose scores did not change (76), 53 remained normal, eight maintained useful but subnormal status, five were stabilised with residual motor function, three kept some sensory perception and two had complete motor and sensory loss. One patient deteriorated from residual motor function to complete motor loss. The outcome for sphincter dysfunction (8) was not clear from the notes. In no case was a specific change in function documented.

Discussion: Surgical treatment of malignant spinal tumours is worthwhile. Posterior approaches are versatile and should be considered. Surgery is effective in the management of pain and preserves or may significantly improve neurologic function.