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

Outcomes after completing growth-friendly surgical treatment for early-onset scoliosis in patients with skeletal dysplasia

Aims

The aim of this study was to compare outcomes after growth-friendly treatment for early-onset scoliosis (EOS) between patients with skeletal dysplasias versus those with other syndromes.

Methods

We retrospectively identified 20 patients with skeletal dysplasias and 292 with other syndromes (control group) who had completed surgical growth-friendly EOS treatment between 1 January 2000 and 31 December 2018. We compared radiological parameters, complications, and health-related quality of life (HRQoL) at mean follow-up of 8.6 years (SD 3.3) in the dysplasia group and 6.6 years (SD 2.6) in the control group.

Results

Mean major curve correction per patient did not differ significantly between the dysplasia group (43%) and the control group (28%; p = 0.087). Mean annual spinal height increase was less in the dysplasia group (9.3 mm (SD 5.1) than in the control group (16 mm (SD 9.2); p < 0.001). Mean annual spinal growth adjusted to patient preoperative standing height during the distraction period was 11% in the dysplasia group and 14% in the control group (p = 0.070). The complication rate was 1.6 times higher (95% confidence interval (CI) 1.3 to 2.0) in the dysplasia group. The following complications were more frequent in the dysplasia group: neurological injury (rate ratio (RR) 5.1 (95% CI 2.3 to 11)), deep surgical site infection (RR 2.2 (95% CI 1.2 to 4.1)), implant-related complications (RR 2.0 (95% CI 1.5 to 2.7)), and unplanned revision (RR 1.8 (95% CI 1.3 to 2.5)). Final fusion did not provide additional spinal height compared with watchful waiting (p = 0.054). There were no significant differences in HRQoL scores between the groups.

Conclusion

After growth-friendly EOS treatment, patients with skeletal dysplasias experienced a higher incidence of complications compared to those with other syndromes. Surgical growth-friendly treatment for skeletal dysplasia-associated EOS should be reserved for patients with severe, progressive deformities that are refractory to nonoperative treatment.

[Correction of complex defomities around the Knee Joint]

Complex deformities around the knee joint are usually severe and have several aetiologies. They can be present in one or more planes, with variations in severity between planes. The occurrence and progression of the deformity can be influenced by local and systemic factors. Several types of osteotomies and fixation methods are available to correct these complex deformities. The selection of the osteotomy used to correct a deformity depends on the type of deformity, its severity and its aetiology. Therefore, precise planning taking into consideration the above factors is necessary to achieve the goal.

SLC26A2-Associated Diastrophic Dysplasia and rMED-Clinical Features in Affected Finnish Children and Review of the Literature

Diastrophic dysplasia (DTD) is a rare osteochondrodysplasia characterized by short-limbed short stature and joint dysplasia. DTD is caused by mutations in SLC26A2 and is particularly common in the Finnish population. However, the disease incidence in Finland and clinical features in affected individuals have not been recently explored. This registry-based study aimed to investigate the current incidence of DTD in Finland, characterize the national cohort of pediatric subjects with DTD and review the disease-related literature. Subjects with SLC26A2-related skeletal dysplasia, born between 2000 and 2020, were identified from the Skeletal dysplasia registry and from hospital patient registry and their clinical and molecular data were reviewed. Fourteen subjects were identified. Twelve of them were phenotypically classified as DTD and two, as recessive multiple epiphyseal dysplasia (rMED). From the subjects with available genetic data, 75% (9/12) were homozygous for the Finnish founder mutation c.-26+2T>C. Two subjects with rMED phenotype were compound heterozygous for p.Arg279Trp and p.Thr512Lys variants. The variable phenotypes in our cohort highlight the wide spectrum of clinical features, ranging from a very severe form of DTD to milder forms of DTD and rMED. The incidence of DTD in Finland has significantly decreased over the past decades, most likely due to increased prenatal diagnostics.

Corrections of lower limb deformities in patients with diastrophic dysplasia

OBJECTIVE

Accurate understanding of the cause of the underlying pathology in children with diastrophic dysplasia would help in designing targeted management of their locomotion.

METHODS

Diastrophic dysplasia was diagnosed in twelve patients (nine girls and three boys; age range 1-14 years), all of whom presented with small stature and apparent short extremities. Club foot (mostly talipes equinovarus) was the most frequent and consistent abnormality. Concomitant abnormalities such as hip flexion contracture, flexion contractures of the knees with excessive valgus deformity and lateral patellar subluxation, were also encountered. Muscle ultrasound and muscle magnetic resonance imaging imaging showed no myopathic changes and muscle biopsies and the respiratory chain were normal. Serum choline kinase and plasma lactate concentrations were normal.

RESULTS

Surgical correction of the foot and ankle in patients with diastrophic dysplasia is extremely difficult because of the markedly distorted anatomy. In all of these children, plantigrade foot was achieved along with the improved function of the locomotor system. Mutations of the diastrophic dysplasia sulfate transporter (also known as solute carrier family 26 member 2) were encountered.

CONCLUSION

Arthrogryposis multiplex is the usual terminology used to describe the abnormality in infants with multiple contractures. Diligent orthopaedic care should be provided based on an accurate understanding of the associated syndromes in such children.

Walking ability in patients with diastrophic dysplasia: a clinical, electroneurophysiological, treadmill, and MRI analysis

Patients with diastrophic dysplasia have walking difficulties of obscure etiology; some are even wheelchair-bound. To explore the problem, physical examination, treadmill, magnetic resonance imaging (MRI), and electroneurophysiologic studies were performed on 87 patients (56 females, 31 males) with an average age of 31 (range 3-56) years. Mobility of the spine, hips, knees, and feet was diminished. Some of the patients were obese (mean body mass index 27.0 kg/m). In the treadmill study, patients were able to walk an average of 638 m (range 0-1,618 m). On MRI, five patients showed compression of neural structures; one of them also had clinical symptoms. Somatosensory evoked potentials and electroneuromyography revealed evidence of compression of neural structure in three (3%) and two (3%) patients, respectively. The walking difficulties seem to have a multifactorial etiology: flexion contractures of the knees, early and rapid osteoarthrosis, equinus or equinovarus foot deformities, and obesity, but only rarely spinal stenosis.

Early degeneration of the knee in diastrophic dysplasia: an MRI study

Magnetic resonance imaging (MRI) findings of 23 patients (13 females, 10 males; 45 knees) with diastrophic dysplasia were examined. The age of the patients ranged from 5 to 40 years (mean 20.5 years). T1- and T2-weighted MR images were obtained. MRI revealed degenerative changes in the articular cartilage of the knees from age 6 years. The subchondral bone of the distal femur was often fragmented, and cartilaginous intrusions from the growth plate into the metaphysis were noted. Menisci developed abnormally. In 43 (96%) of the knees studied, the anterior cruciate ligament was either thinned or rudimentary, or could not be detected. The posterior cruciate ligament was affected in 40 (89%) knees but was at least rudimentary in all patients. In contrast, the patellar tendon was thick and short and the patella was in an inferior position The patella showed bony fragmentation in 32 (71%) knees. The pathologic changes in all joint compartments increased with age, reflecting early degeneration of the knee in this disease.

Total knee arthroplasty in patients with diastrophic dysplasia

BACKGROUND

Diastrophic dysplasia results in severe disproportionate short stature, generalized joint deformities, and early osteoarthritis. The knee joint often has an abnormal valgus position and is unstable, and degeneration of all joint compartments occurs, even during growth. The purpose of our study was to evaluate the clinical and radiographic results of total knee arthroplasty in a series of patients with diastrophic dysplasia.

METHODS

Between February 1992 and March 2000, twenty-one primary total knee arthroplasties were performed on fourteen consecutive patients with severe osteoarthritis due to diastrophic dysplasia. The patients were followed prospectively with clinical examinations, determination of the Hungerford knee scores, and radiographs. Preoperatively, ten knees had chronic dislocation of the patella. The mean duration of follow-up was 3.4 years.

RESULTS

The mean Hungerford knee pain and total scores improved from 5.8 points and 46 points preoperatively to 50 points and 83 points, respectively, at the final follow-up examination (p < 0.001 for both comparisons). Two knees required a distal femoral corrective osteotomy because of metaphyseal angulation. None of the total knee arthroplasties had to be revised during the follow-up period. Six complications were recorded.

CONCLUSIONS

Total knee arthroplasty substantially improved the function of patients with diastrophic dysplasia. Additional peripatellar procedures were commonly needed, and complications were frequent.

Total hip arthroplasty in diastrophic dysplasia

BACKGROUND

Diastrophic dysplasia results in severe disproportionate growth failure, multiple joint deformities, and early osteoarthritis of the hips. Mortality is increased in early childhood, but thereafter life expectancy is normal. Because of severe flexion deformities, resting pain, and diminished movements of the hip joints, total hip arthroplasty is indicated at an early age. The purpose of our study was to evaluate prospectively the midterm results of total hip arthroplasty in a consecutive series of patients with diastrophic dysplasia.

METHODS

Between 1982 and 1996, forty-one total hip replacements were performed in twenty-four consecutive patients with diastrophic dysplasia (mean age, forty-one years) at our hospital. The patients were followed prospectively for a minimum of five years with clinical examination, determination of Harris hip scores, and radiographs. Twenty-two patients (thirty-eight hips) were examined clinically and radiographically at the time of follow-up, and the remaining two patients (three hips) were contacted only by telephone. The mean duration of follow-up was 7.8 years.

RESULTS

The mean Harris hip score increased from 44 points (range, 25 to 66 points) before the operation to 70 points (range, 37 to 89 points) at the final follow-up examination (p < 0.001). Ten complications (24%) were recorded. Five (12%) of the forty-one hips required revision because of aseptic loosening of the acetabular component at a mean of 9.4 years after the primary operation. No revisions were due to aseptic failure of the femoral component.

CONCLUSIONS

Implant survival was good and the Harris hip scores increased significantly after total hip arthroplasty in patients with diastrophic dysplasia. However, shortening femoral osteotomy and transposition of the greater trochanter, adductor and flexor tenotomies, and modification of the femoral stem were frequently needed. Total hip arthroplasty is recommended for patients with diastrophic dysplasia and severe degeneration of the hip joints, even for those who are relatively young.

LEVEL OF EVIDENCE

Therapeutic study, Level IV (case series [no, or historical, control group]). See Instructions to Authors for a complete description of levels of evidence.