Scoliosis in patients with diastrophic dysplasia: a new classification.

STUDY DESIGN: Scoliosis in patients with diastrophic dysplasia was analyzed. OBJECTIVES: To study the natural history of scoliosis and to classify the patients with different types of scoliosis. SUMMARY OF BACKGROUND DATA: Typical findings in diastrophic dysplasia are short-limbed short stature, multiple joint contractures, early degeneration of joints, and spinal deformities. The largest studies have reported scoliosis in 37% to 88% of the patients with this rare skeletal dysplasia. The natural history of the deformity is unknown. METHODS: Of the 130 unselected patients, 98 (75%) who were older than 16 years and/or had undergone surgery at the time of the last radiograph were included in the final analysis. These 98 patients included 37 males and 61 females. Their ages at the first radiograph ranged from newborn to 78 years (average, 21 years). The mean follow-up period was 20 years (range, 2-41 years) for 80 patients. Standard standing anteroposterior and lateral radiographs were taken. The degrees of scoliosis, kyphosis, and lordosis were measured according to the Cobb method. Classification of the scoliosis was based on the patient's age at onset of scoliosis, the rate of progression, the magnitude of the scoliosis at the end of growth, and the curve pattern. RESULTS: Of the 98 patients in this study, 86 (88%) had scoliosis. This difference was highly significant statistically (P < 0.001), as compared with the normal population. The frequency of scoliosis was 90% among females and 84% among males. Scoliosis can be divided further into three subtypes: early progressive (11 patients), idiopathic-like (41 patients), and mild nonprogressive (33 patients). One patient had a congenital scoliosis. CONCLUSIONS: Scoliosis is very common in patients with diastrophic dysplasia. The natural history of scoliosis varies from severe deformity with rapid progression to mild deformity without any progression. The authors suggest that the classification described in this report offers a tool for the predicting natural history of scoliosis in diastrophic dysplasia, and for adjusting the timing of surgery in individual patients.

Thoracic and lumbar spine in diastrophic dysplasia: a clinical and magnetic resonance imaging analysis.

STUDY DESIGN: Cross-sectional study to evaluate the thoracic and lumbar spine in patients with diastrophic dysplasia (DD). OBJECTIVES: To find the causative factors behind the spinal deformities and restricted mobility of the spine. SUMMARY OF BACKGROUND DATA: Typical findings in this skeletal dysplasia are short-limbed stature, multiple joint contractures, early degeneration of joints, and spinal deformities such as cervical kyphosis, scoliosis, and exaggerated lumbar lordosis. The pathogenic mechanism of scoliosis is unknown. METHODS: A physical examination was performed on 88 patients (55 females, 33 males) with an average age of 31 years (range, 3-56). Magnetic resonance (MR) images from T2 to S1 and radiographs were obtained. Degree of scoliosis was measured according to Cobb from standing radiographs. The anatomy of the medulla and the size of the spinal canal were assessed. The transverse dural tube area was measured from L2 to S1. Disc space, degeneration, and protrusions were evaluated. Vertebral abnormalities, if any, facet joint degeneration and the state of the spinal muscles were also assessed. RESULTS: Physical examination showed diminished mobility of the spine. Scoliosis was noted in 70 patients with an average of 42 degrees (range, 11-188 degrees ). The mean transverse area of the dural tube ranged from 94 mm(2) at L2-L3 to 57 mm(2) at L5-S1. The area was smaller at all levels compared with reference values (P < 0.001). One patient had severe thoracic and lumbar spinal stenosis. Five patients had compression of neural structures in the lumbar spinal canal in MR images, but had no clinical symptoms. All patients exhibited narrowed disc heights and a decrease in the signal intensity of discs on T2-weighted images. The prevalence of disc protrusions was low; three patients had a prolapse in the lumbar spine. Two patients displayed vertebral anomalies. All patients also had muscular atrophy and degenerative-like facet joint hypertrophy. The severity of these changes increased with age. CONCLUSIONS: Abnormal disc structure and rapid degeneration explain the diminished decreased mobility of the spine and may be a causative factor in the development of scoliosis. Muscular atrophy may be caused by reduced physical activity and rigid spinal deformities. The spinal canal is narrowed, but symptomatic lumbar spinal stenosis is uncommon.

Elevated protein content and prolyl 4-hydroxylase activity in severely degenerated human annulus fibrosus.

Alterations involved with the intervertebral disc degeneration are partly well described, however, it is not so well known how collagen network is affected by the disease. We analyzed the rate of collagen biosynthesis (estimated by the enzymic activities of prolyl 4-hydroxylase and galactosylhydroxylysyl glucosyltransferase) and the level of hydroxylysylpyridinoline and lysylpyridinoline crosslinks both in normal (n=7) and degenerated (n=7) human annulus fibrosus. The activity of prolyl 4-hydroxylase was significantly increased in degenerated tissue. However, no significant changes in the collagen content or in the amount of hydroxylysylpyridinoline and lysylpyridinoline collagen crosslinks were observed. On the other hand, the content of soluble proteins was significantly increased. Our results suggest that collagen biosynthesis is increased in degenerated human annulus fibrosus, obviously to compensate the impairment of collagen fibers. The faster turnover of collagen in degenerated annulus fibrosus, suggested by the increased prolyl 4-hydroxylase activity and unchanged collagen content, seems not to cause any significant changes in its mature pyridinium crosslink concentrations.

Development of trunk asymmetry in a cohort of children ages 11 to 22 years.

STUDY DESIGN: A cohort study with a follow-up period of 11 years. OBJECTIVES: To study the growth of the spine with a focus on the development of trunk asymmetry and scoliosis. SUMMARY OF BACKGROUND DATA: Trunk asymmetry, a common phenomenon at adolescence, can be considered the clinical expression of scoliosis. The importance of the pubertal growth spurt has been stressed in the natural history of scoliosis. However, no cohort studies have focused on the ascending and descending phase of the spine's peak growth and the development of trunk asymmetry. METHODS: The cohort consisted of all the fourth-grade school children in the Western school district of Helsinki, Finland, in the spring of 1986. These 1060 children (515 girls and 545 boys), from the average age of 11 to 14 years, were invited to undergo annual examinations. The 855 children (80.7%) who had participated in the study at the age of 14 years were invited to a reexamination at the age of 22 years. This invitation was accepted by 430 (208 women and 222 men; 54%) of those invited. The forward bending test, the spinal pantography, and the anthropometric measurements were carried out by the same author (M.N.) throughout this study. RESULTS: At 22 years of age, 30% of the adults were found to be symmetric, with a hump less than 4 mm in the forward bending test, whereas 51% had a hump of 4 to 9 mm, and 19% had a hump 10 mm or larger (major asymmetry). The directional asymmetry of trunk surface, a skew to the right at the thoracic level and to the left at the lumbar level at puberty, remained constant at adult age. The prevalence of major trunk asymmetry at adult age was the same in both women and men, in contrast to the female predominance at puberty in this cohort. There were close correlations in the degrees of thoracic and lumbar asymmetry between puberty and adult ages. CONCLUSIONS: The shape of the back develops mainly during the pubertal growth spurt at ages 12 to 14 years in girls and boys. Trunk asymmetry (and mild scoliosis) seems as prevalent in young adult women as in men, although at puberty idiopathic scoliosis was twice as prevalent among girls as among boys in this cohort.

Cervical spine in diastrophic dysplasia: an MRI analysis.

In this cross-sectional study, we evaluated the cervical spine in patients with diastrophic dysplasia (DD) by using magnetic resonance imaging (MRI). From 90 (57 female, 33 male) patients of different ages (0.3-56.0 years), T1- and T2-weighted images were obtained. The craniocervical junction and status of the medulla were examined, and the transverse areas of dural tube and medulla were measured. Alignment of the cervical spine, vertebral abnormalities, and disc changes also were evaluated. The cervical spinal canal was moderately narrowed, particularly in adults. The transverse areas of the medulla and especially of the dural tube were smaller compared with a normal population (p < 0.0001). There was no stenosis of the foramen magnum in patients with DD, but the spinal canal was narrowed. Degenerative changes were common. In all age groups, intervertebral discs were dark and disc heights were narrowed. Three (3%) patients (two children, one adult) had cervical kyphosis. Compression of the medulla was noted in association with severe cervical kyphosis in one child and one adult. Typical findings of the cervical spine in DD were exceptionally wide foramen magnum, narrowed spinal canal and early degenerative changes, and in older age groups, especially midcervically narrowed spinal canal. Severe cervical kyphosis caused medullar compression. The intervertebral discs developed abnormally. Abnormal disc structure may be one etiologic factor in the development of cervical kyphosis. Early and rapid progression of the degenerative changes is a normal finding in patients with DD, regardless of their age, and this also explains the stiffness of the cervical spine in clinical examination.

Cervical kyphosis in diastrophic dysplasia.

STUDY DESIGN: An evaluation of cervical kyphosis in diastrophic dysplasia from newborn to adult life. OBJECTIVES: To discover the prevalence and natural history of cervical kyphosis in diastrophic dysplasia. SUMMARY OF BACKGROUND DATA: Typical findings in this rare skeletal dysplasia are sport-limbed short stature, multiple joint contractures, early degeneration of joints, and spinal deformities such as cervical kyphosis, scoliosis, and exaggerated lumbar lordosis. In diastrophic dysplasia, spontaneous resolution of cervical kyphosis has been reported, but so have severe forms causing medullar compression leading to quadriplegia and death. The prevalence and clinical outcome of the kyphosis are not known. METHODS: The radiographic natural history of the cervical spine was studied in 120 patients. They varied in age from newborns to 63-year-olds. The average follow-up time in 26 living patients with cervical kyphosis was 10.0 years. RESULTS: Midcervical kyphosis was noted in 29 patients (24%) in their first radiograph. In 25 patients, the first radiographs were taken before the age of 18 months, and 24 of these patients (96%) had cervical kyphosis. The most severe case was that of a 32-year-old patient with a 165 degrees kyphosis. In the 24 patients, the kyphosis resolved spontaneously at an average age of 7.1 years. Three patients with a severe kyphosis died; one patient is alive. One patient, a 4-year-old child has mild resolving deformity. CONCLUSIONS: Cervical kyphosis in diastrophic dysplasia usually is shown at the time of birth. It resolves spontaneously during growth and seldom needs treatment. Careful follow-up study and treatment, if necessary, are important tools for avoiding the neurologic problems and fatal outcome.

The knee joint in diastrophic dysplasia. A clinical and radiological study.

We examined clinically and radiologically the knees of 46 patients (27 females and 19 males) with diastrophic dysplasia. The age of the patients varied from newborn to 38 years. A total of 18 patients was followed during their growth until adolescence. The knees of two legally aborted fetuses appeared on examination to be macroscopically normal and congruous. Excessive valgus deformity of the tibiofemoral weight-bearing angle with a mean of 14 degrees was noted in infancy. Most of the patients had marked instability of the knees. The range of movement of the knee began to decrease before the age of five years. There were signs of early degeneration and deformation of the bony epiphyses before the age of six years. The patellofemoral joint was abnormal from an early age. A marked patella infera, often associated with a lateral position of the patella with bony fragmentation, was noted. The knee in diastrophic dysplasia is basically unstable, showing early deformation of the subchondral bone and degeneration of the joint.

Health-related quality of life in patients with diastrophic dysplasia.

Diastrophic dysplasia (DD), a congenital skeletal dysplasia, is characterized by short, disproportionate stature, multiple severe spinal and joint deformities, and normal mental status. The health-related quality of life (HRQOL) of patients with DD was measured by a standardized fifteen-dimensional (15D) method, that includes a questionnaire and a valuation task. Eighteen patients (5 males and 13 females) with a mean age of 23 years (range 17-31 years), representing half of the Finnish patients with DD in this age group, completed the questionnaire and the valuation task. The data obtained were compared with those of 273 age- and sex-matched controls. A 15D profile was drawn, and the average importance weight of each dimension and the average within-dimension level values were calculated for both groups. The average 15D score, describing the overall HRQOL, was derived for both groups using the evaluations of each group. The health profiles of the groups differed significantly in several dimensions. When the health levels within the dimensions were concerned, the controls rated all values deviating from "normal" lower than did the patients. The average 15D scores of the patients with DD were significantly lower than those of the controls. The 15D scores were higher in both groups when the evaluations of the patients with DD were used. The study showed that, although the overall HRQOL of the patients with DD was inferior to that of the controls, the patients showed greater adaptability to deviations in health status than did the controls.

Development of the hip in diastrophic dysplasia.

We examined 50 patients with diastrophic dysplasia both clinically and radiologically. Two legally aborted fetuses were dissected. The mean age of the patients was 16.2 years (newborn to 38) and the mean follow-up was 11.4 years (3 months to 34 years). The fetal hips and MRI of newborn infants showed congruity and no significant joint deformity. Flexion contracture of the hip became evident later in 93% and was progressive. The radiological appearance of the proximal femoral ossific nuclei was delayed and in 17% of males and 28% of females the ossific nuclei had not appeared by the age of 12 years. Radiological measurements differed considerably from reference values and were related to the rapid and progressive restriction of rotational movement and the increase in flexion contracture. The typical findings were flattening and inferomedial bulking of the femoral head and a double-hump deformation. The changes in the hip led to secondary osteoarthritis before early middle age. We describe the clinical and radiological measurements which define the early degeneration of the joint.

Pregnancy and delivery in patients operated by the Harrington method for idiopathic scoliosis.

The course and outcome of 142 pregnancies in 146 patients operated between 1970 and 1975 by the Harrington method for idiopathic scoliosis were studied to determine the effects of scoliosis on pregnancy and childbirth and the effects of pregnancy on the remaining fused and unfused scoliotic curvatures. Occurrence of and sick leave due to low back pain during pregnancy was determined. The patients, all originally treated at the Orthopaedic Hospital of the Invalid Foundation (Orton) in Helsinki, Finland, were invited to a clinical and radiological re-examination on average 19 years following surgery. The results show that pregnancy does not significantly increase fused scoliotic curvatures nor the remaining unfused curvatures. A somewhat higher proportion of children (23%) were delivered by cesarean section than in the general population (15%; P < 0.01), but this result should only be taken as suggestive. Rates of complications of pregnancy and in labor did not differ from those in the background population. The offspring were healthy. Low back pain during pregnancy occurred in about 40% of our patients, but was severe enough to cause sick leave only in 11% of the pregnancies.

Disc herniation in the lumbar spine during growth: long-term results of operative treatment in 18 patients.

We studied 18 patients who had undergone surgery for herniated lumbar discs between the ages of 11 and 17 years. The inclusion criteria for girls was an age of 15 years or below and for boys 17 or below at surgery. The mean follow-up time was 10 years and the clinical outcome was good. Age at surgery and length of the follow-up had no effect on the result. The radiological disc height at follow-up did not correlate with the follow-up time or age of the patient at operation. MRI scans at follow-up from ten patients operated at less than 15 years of age revealed multilevel disc degeneration but favourable clinical results.

Disc degeneration in young patients with isthmic spondylolisthesis treated operatively or conservatively: a long-term follow-up.

The purpose of this long-term follow-up was (1) to investigate disc changes in the olisthetic segment in patients treated conservatively, (2) to compare disc changes above the slipped vertebra in conservatively treated patients with those in operatively treated patients, and (3) to establish possible relations of disc changes to the degree of the slip and to subjective back pain symptoms of the patients. The subjects were 227 patients with isthmic L5 olisthesis diagnosed under 20 years of age (mean 13.8 years) with a mean follow-up of 15.4 (range 5-30) years. Of these, 145 patients had been treated with segmental fusion and 82 had been treated conservatively. At follow-up, standing anteroposterior and lateral radiographs as well as flexion/extension views of the lumbar spine were taken. Disc degeneration was graded semiquantitatively: 0 = normal disc height, 1 = decrease of disc height < 50%, 2 = decrease > or = 50%, and 3 = obliteration of the disc. In the conservatively treated patients degeneration of the olisthetic disc was distributed by grade as follows: O: n = 38, 1: n = 24, 2: n = 14, 3: n = 6. No motion at all was observed in the olisthetic segment in 40 patients (48%) with a mean slip of 30%, segmental motion of 4 degrees-18 degrees was found in 42 patients with a mean slip of 14%. There was a statistically significant association of the degree of slip to the severity of disc degeneration and non-mobility of the segment. Grade 1 degeneration of the L4/5 disc occurred in 25.6% of the conservatively treated patients and in 32% of 48 patients treated with L5-S1 fusion. This correlated with the severity of the slip, but not with pain symptoms or pathologic segmental mobility at the time of follow-up. Out of 84 patients with L4-S1 fusion, in 17% grade 1 degeneration of the L3/4 disc was observed, and 3 out of 13 patients (23%) with L3-S1 fusion had grade 1 degeneration of the disc above the fusion. The disc changes had no correlation with subjective pain symptoms. It is concluded that the natural course of isthmic spondylolisthesis is associated with disc degeneration and spontaneous stabilization of the olisthetic segment. Fusion operations do not significantly increase the rate of disc degeneration in the adjacent disc above the fusion after a mean postoperative follow-up of 13.8 years. No correlation between the number of degenerated discs or the degree of degeneration and subjective low back pain symptoms was found.

Accuracy of pedicle screw insertion: a prospective CT study in 30 low back patients.

A prospective study of the accuracy of titanium pedicle screw placement in 30 low back operations was performed. The postoperative plain radiographs and CT reformation images were evaluated by two independent radiologists. Thirty-two out of 152 screws (21%) perforated the pedicle cortex. One-tenth of the perforations was detected with conventional radiography. In ten patients (33%) all the screws were located within the pedicle. The clinical significance of this study lies in the finding that pedicle perforations are more frequent than is generally believed and that, in spite of the many malplacements, no screw that perforated by less than 4.0 mm caused neurological problems. Only one nerve root lesion was detected.

Results of a trial of anterior or circumferential lumbar fusion in the treatment of severe isthmic spondylolisthesis in young patients.

The radiological and clinical results in 27 patients operated on for severe isthmic spondylolisthesis at age < 20 years with uninstrumented anterior interbody fusion alone in 11 or combined anterior and posterolateral (circumferential) fusion in 16 are reported. The mean follow-up time was 5.9 +/- 2.4 years. The two groups were comparable with regard to age at operation, sex, preoperative symptoms, mean preoperative slip and sagittal rotation angle. The follow-up assessment, made by an independent observer, included interview, Oswestry disability index, physical examination, functional tests, and plain radiographs. At follow-up, there were no statistical differences between the groups in subjective, clinical, and functional outcomes. Follow-up radiographs showed no progression of slip in either group. The sagittal rotation angle worsened slightly in the anterior fusion group but improved by 5.8 degrees (p < 0.001) on the average in the combined fusion group. There were no instances of pseudarthrosis. Two patients, one in each group, were reoperated on early for postoperative peroneal weakness; both recovered. The clinical and functional results were satisfactory in most cases. The radiological results concerning the sagittal rotation angle were superior in the combined fusion group, but whether this will affect the long-term clinical result is not known.

Sense of coherence and outcome of anterior low-back fusion. A 5- to 13-year follow-up of 85 patients.

Eighty-five patients were followed up for more than 5 years after an anterior low-back fusion which was performed for a chronically painful low-back condition. The mean age of the patients at the time of the index operation was 35 years, the mean duration of their symptoms was 8 years, and 50 (59%) had undergone previous low-back surgery. Preoperatively the patients were on average severely disabled according to the Oswestry scale, and the self-rated improvement at the follow-up on average 7.4 years after surgery was significant, the mean index being 24%. In 29 (34%) patients, the Oswestry index was 10% or below, reflecting none or very little discomfort as a result of the surgery. In all age groups, women had better results than men. The best outcome was found in patients with no previous low-back surgery. Half of the patients returned to work. Thirteen patients needed new surgery because of nonunion. The use of transpedicular fixation did not produce better results. The sense of coherence scale assessing the patient's successful coping capability had a very good predictive value in the whole series, and this predictive value was especially good in patients between 35 and 50 years of age. Also, the shorter duration of symptoms was an important predictor of a successful outcome, and the end results in patients who had a longer duration of preoperative low-back symptoms tended to be poor.

Sense of coherence and outcome of low-back surgery: 5-year follow-up of 80 patients.

Eighty adult patients, 33 men and 47 women, mean age 46 years (SD 11.8, range 19-74 years), were evaluated 5 years after low-back surgery. The mean duration of symptoms before operation was 8.7 (SD 7.1) years. The purpose was to evaluate the 5-year outcome of low-back surgery, to find the best predictors for the outcome, and to find out if a correlation exists between the patient's sense of coherence and the outcome of low-back surgery. The mean Oswestry pain index for the whole group of patients improved from 3.8 to 2.7 (P < 0.001). The greatest improvement in pain was found in the group aged 35-50 years. In those over 50 years old, pain improved significantly more in women than men. Regarding walking ability, the mean Oswestry gait index for the whole group improved from 3.0 to 1.9 (P < 0.001), with men over 50 years old achieving the greatest improvement in their walking. The mean Oswestry total index for the whole group was 41% before surgery, reflecting severe disability, and 25% at follow-up, reflecting moderate disability (P < 0.001). There was no difference between the mean values for men and women. Patients who had undergone several previous operations fared less well in the Oswestry total index, though their improvement was still significant (P < 0.05). The postoperative Oswestry total index values correlated significantly with the sense of coherence (SOC) scale values (r = -0.23, P < 0.05). In all patients, the Oswestry total index before the index operation is suggested to be a predictor of the final outcome. In multiple regression analysis, the number of previous operations and the preoperatively recorded Oswestry total index appeared to be the best predictors for outcome of low-back surgery. We also found that the SOC scale correlated significantly with the Oswestry total index and seems to provide a possible explanation of ability to cope with the disability and pain associated with low-back disorders.

Left handedness and risk of thoracic hyperkyphosis in prepubertal schoolchildren.

BACKGROUND: Hand dominance and spinal posture were studied for their prediction of the development of thoracic hyperkyphosis during the pubertal growth spurt. METHODS: The cohort consisted of all the fourth-grade school children of the Western School District of Helsinki, Finland, in the spring of 1986. They were examined annually from the mean age of 10.8 to 13.8 years. Handedness was determined at the baseline examination by observing the hand with which the child was writing. Anthropometric measurements, posture and growth were followed-up annually. A lateral standing radiograph was undertaken in those children who had pronounced thoracic kyphosis in spinal pantography. Kyphotic angles > or = 45 degrees were considered hyperkyphotic. RESULTS: In both girls and boys, left handedness was found to be a powerful determinant of hyperkyphosis. In left handed children the odds ratio (OR), adjusted for baseline spinal measurements, was 4.11 (95% confidence interval [CI]: 1.39-12.13). Hump size measured by the forward bending test also predicted significantly the development of thoracic hyperkyphosis (OR = 1.48; 95% CI: 1.23-1.76, per one degree). CONCLUSIONS: Left handedness may be a risk factor for thoracic hyperkyphosis during the pubertal growth spurt.

Anthropometric measurements and the incidence of low back pain in a cohort of pubertal children.

STUDY DESIGN: The authors studied the anthropometric measurements to predict low back pain (LBP) in a cohort of growing adolescents. SUMMARY OF BACKGROUND DATA: The cohort consisted of all the fourth-grade school children of the western school district of Helsinki, Finland, in the spring of 1986. They were examined annually from the mean age of 11.8 to 13.8 years. METHODS: The forward bending test, measurements of total arm length, pelvic equilibrium, and spinal pantographs were carried out by the same physiatrist. A standardized pain questionnaire presented at the final examination obtained the history of LBP. Of the original cohort of 1060 children, those 859 (408 girls and 451 boys) who participated in all the examinations and had not had LBP until the age of 12.8 years were included in this study. RESULTS: The 1-year (from 12.8 to 13.8 years) incidence of LBP was 18.4% in girls and 16.9% in boys. Trunk asymmetry measured by the forward bending test and sitting height were significant determinants of the incidence of LBP. In the whole cohort, the odds ratio (OR) of trunk asymmetry adjusted for all the other risk determinants was 1.19 and its confidence interval (CI) was 1.00-1.39 per one standard deviation increase of the trunk hump. In the multivariate analysis comprising both sexes, OR per one standard deviation increase of sitting height was 1.24, (95% CI 1.03-1.46). In boys, standing height (OR 1.40, 95% CI 1.13-1.65, per one standard deviation) and sitting height (OR 1.35, 95% CI 1.09-1.63, per one standard deviation) were positively associated with the risk of LBP. These associations were not significant in girls. CONCLUSIONS: Sitting height and trunk asymmetry may contribute to LBP in pubertal children. The role of anthropometric characteristics seems, however, modest.

Periosteal and perichondral grafting in reconstructive surgery.

Periosteum consists of multipotent mesodermal cells, and the influence of the environment on differentiation of cells of free periosteal grafts has been demonstrated in experimental studies. Periosteum has the capacity to form all varieties of connective tissue. The periosteum has osteogenic capacity, but it can also be used to promote cartilage formation in a chondrotrophic environment. Free periosteal grafts transplanted to the completely chondrectomized articular surfaces of patellae in experimental animals differentiated into cartilage. Joint motion appeared to be one of the chondrogenesis-promoting factors. The authors are optimistic about the potential clinical results with these types of grafts. Also, periosteal resurfacing of the metatarsal head was found to be suitable in the treatment of hallux rigidus and Freiberg's disease. Findings in growing rabbits showed that spinal fusion can be achieved with free periosteal grafts. This technique has been used to treat lumbar lytic spondylolisthesis in young patients, and the method produced clinical and radiologic results that were comparable with those obtained using bone transplants. This work indicates that some of the adverse effects of lumbar spinal fusion (e.g., postoperative spinal stenosis) can be avoided by using osteoperiosteal fusion. Also, periosteal grafting has proved useful in the treatment of thoracolumbar scoliosis. Free periosteal grafting has been used to treat congenital clefts of the maxilla and tracheal cartilage defects.