Double-layered Patella Research Articles

Exome sequencing reveals a novel COL2A1 mutation implicated in multiple epiphyseal dysplasia.

Mutations in the COMP, COL9A1, COL9A2, COL9A3, MATN3, and SLC26A2 genes cause approximately 70% of multiple epiphyseal dysplasia (MED) cases. The genetic changes involved in the etiology of the remaining cases are still unknown, suggesting that other genes contribute to MED development. Our goal was to identify a mutation causing an autosomal dominant form of MED in a large multigenerational family. Initially, we excluded all genes known to be associated with autosomal dominant MED by using microsatellite and SNP markers. Follow-up with whole-exome sequencing analysis revealed a mutation c.2032G>A (p.Gly678Arg) in the COL2A1 gene (NCBI Reference Sequence: NM_001844.4), which co-segregated with the disease phenotype in this family, manifested by severe hip dysplasia and osteoarthritis. One of the affected family members had a double-layered patella, which is frequently seen in patients with autosomal recessive MED caused by DTDST mutations and sporadically in the dominant form of MED caused by COL9A2 defect.

SLC26A2 disease spectrum in Sweden – high frequency of recessive multiple epiphyseal dysplasia (rMED)

Diastrophic dysplasia (DTD) is an autosomal recessive skeletal dysplasia caused by SLC26A2 mutations. Clinical features include short stature, joint contractures, spinal deformities, and cleft palate. SLC26A2 mutations also result in other skeletal dysplasias, including the milder recessive multiple epiphyseal dysplasia (rMED). DTD is overrepresented in Finland and we speculated that this may have influenced the prevalence and spectrum of SLC26A2-related skeletal conditions also in Sweden. We reviewed the patient registry at Department of Clinical Genetics, Karolinska University Hospital, Stockholm to identify subjects with SLC26A2 mutations. Seven patients from six families were identified; clinical data were available for six patients. All but one patient had one or two copies of the Finnish SLC26A2 founder mutation IVS1+2T>C. Arg279Trp mutation was present in compound heterozygous form in five patients with phenotypes consistent with rMED. Their heights ranged from -2.6 to -1.4 standard deviation units below normal mean and radiographic features included generalised epiphyseal dysplasia and double-layered patellae. Two rMED patients had hypoplastic C2 and cervical kyphosis, a severe manifestation previously described only in DTD. Our study confirms a high prevalence of rMED in Sweden and expands the phenotypic manifestations of rMED.

Bilateral Double-Layered Patella: MRI Findings and Fusion with Multiple Headless Screws: A Case Report.

The double-layered patella (DLP) was first described by Buttner in 19251. It is a rare entity that is often associated with an autosomal recessive form of multiple epiphyseal dysplasia (MED) caused by a homozygous diastrophic dysplasia sulfate transporter (DTDST) gene mutation2-5, although COMP6 and COL9A27 deletions have also been reported to cause DLP. DLP is a relatively mild form of MED, and clinical findings are often limited to bilateral recurrent anterior knee pain and early-onset hip osteoarthritis (C653S homozygous DTDST gene)2 as well as mild brachydactyly and clubfoot deformity (R279W homozygous DTDST gene)8. If the soft-tissue interface between the anterior and posterior osseous layers in DLP is stable and allows for little motion, patients may be asymptomatic. In these cases, DLP is often discovered incidentally as part of a broader diagnostic evaluation for MED9. However, if the soft-tissue interface is unstable, considerable motion can occur between the two ossified layers, which can cause symptoms, particularly during knee extension. This can present as a sensation of locking, giving way, or subluxation2, or alternatively as painful clicking or a snapping sensation with flexion near 30° to 40° 10,11. There is very limited information regarding the surgical treatment of symptomatic DLP. In several prior reports, a good clinical outcome was achieved with debridement of the soft-tissue interface and fusion of the osseous layers with screws10-12. In a patient with DLP who had undergone unsuccessful soft-tissue stabilization (Ali-Krogius procedure13), Hinrichs et al. utilized a tibial tuberosity medialization addition to a second soft-tissue stabilization2. We present a case of symptomatic bilateral DLP in an adolescent who was treated with fusion with use of four headless screws. The patient’s parents were …

Fusion of Double-layered Patella Using a Single Small Fragment Partially Threaded Screw

The double-layered patella (DLP) was first described by Büttner in 1925 and is now considered pathognomonic for multiple epiphyseal dysplasia. In this study, we describe the case of an 11-year-old girl with multiple epiphyseal dysplasia and right-sided DLP. The patient presented with intermittent unilateral anterior knee pain and swelling. There was a reproducible high-pitched click with every step. Imaging showed a DLP in good alignment. Surgical management comprised open debridement and fixation of the 2 patellar layers using one 3.5 mm (removed-) partially threaded AO small fragment screw. Standard radiographs of the right knee, 3 years postoperatively, showed sound union of the 2 patellae. The patient now plays sports, and recent examination showed a full range of movement with no instability, effusion, or tenderness. We conclude that surgical fusion of the patellar fragments in DLP using a single small fragment partially threaded screw provides excellent outcome at 3 years follow-up. This case report shows a comparatively simple and economical surgical solution to the problem of DLP.

Surgical management of a double-layered patella: a case report

The double-layered patella (DLP) is a rare intra-articular disorder that in most cases is associated with multiple epiphyseal dysplasia (MED). The DLP usually consists of an anterior and a posterior layer with a cartilaginous interface between the two parts. In this article, we present a case of bilateral DLP of a 17-year-old female adolescent with MED, suffering clinical symptoms on her left knee. Upon clinical examination, a painful "snapping" of the patella at 30-40 degrees flexion of the left knee was evident and two osseous layers could be identified in standard radiographs. Arthroscopic examination revealed a transient cranial displacement of the posterior osteochondral layer at 30-40 degrees knee flexion that replaced beyond 40 degrees knee flexion with a visible jump. Surgical management in this case of DLP comprised open debridement of the soft tissue interface and fusion of the two osseous layers using double-threaded screws leading to an excellent outcome at 12 months follow-up.

Hypertrophie rotulienne: rare anomalie associée à une dysplasie polyépiphysaire

Multiple epiphyseal dysplasia is a genotypic chondrodystrophy characterized by an abnormal shape of numerous epiphyses. Diagnosis is usually made during childhood on an abnormal gait and a reduction of joint mobility associated with radiological changes of the ossification centres. This observation reports on a woman who only consulted at adulthood. Diagnosis was based on a short stature, slight shortening of the extremities and precocious osteoarthritis on the radiographs. Lateral x-rays of the knees revealed a globular hypertrophy of both patellae. This association has rarely been mentioned. A late fusion of an antero-posterior duplication of the ossification centre of the patella seems to be the most plausible physiopathologic hypothesis. Persistence of both ossification centres could result in a coronal double-layered patella, which is also occasionally observed in patients with multiple epiphyseal dysplasia.

Heart-shaped sesamoid in multiple epiphyseal dysplasia

A 15-year-old boy presented with bilateral pain and stiffness in the hips, knees and ankles. He had been known for many years to have recessive multiple epiphyseal dysplasia (MED). Radiographs of the knees showed abnormally shaped knee epiphyses and a double-layered patella (DLP) consisting of anterior and posterior portions (Fig. 1, asterisks). Radiographs of the feet revealed short metatarsal bones and irregularly shaped tarsal bones with ossification. Additionally, there was a peculiar bony fusion of the sesamoid bones of the first toe bilaterally, resulting in a heart-shaped appearance (Fig. 2, arrows). MED is a heterogeneous group of skeletal dysplasias that may show an autosomal dominant or a recessive pattern of inheritance. Abnormalities of epiphyseal ossification are the hallmark of the disorder. DLP is highly diagnostic for recessive MED [1, 2]. The heart-shaped deformity of the sesamoid bones in MED has not been previously reported. The diagnostic significance of this sign remains to be established.

Double-layered patella in multiple epiphyseal dysplasia is not exclusive toDTDST mutation

Double-layered patella in multiple epiphyseal dysplasia is not exclusive toDTDST mutation

A Mutation in COL9A1 Causes Multiple Epiphyseal Dysplasia: Further Evidence for Locus Heterogeneity

Multiple epiphyseal dysplasia (MED) is an autosomal dominantly inherited chondrodysplasia. It is clinically highly heterogeneous, partially because of its complex genetic background. Mutations in four genes, COL9A2, COL9A3, COMP, and MATR3, all coding for cartilage extracellular matrix components (i.e., the alpha2 and alpha 3 chains of collagen IX, cartilage oligomeric matrix protein, and matrilin-3), have been identified in this disease so far, but no mutations have yet been reported in the third collagen IX gene, COL9A1, which codes for the alpha1(IX) chain. MED with apparently recessive inheritance has been reported in some families. A homozygous R279W mutation was recently found in the diastrophic dysplasia sulfate transporter gene, DTDST, in a patient with MED who had a club foot and double-layered patella. The series consisted of 41 probands with MED, 16 of whom were familial and on 4 of whom linkage analyses were performed. Recombination was observed between COL9A1, COL9A2, COL9A3, and COMP and the MED phenotype in two of the families, and between COL9A2, COL9A3, and COMP and the phenotype in the other two families. Screening of COL9A1 for mutations in the two probands from the families in which this gene was not involved in the recombinations failed to identify any disease-causing mutations. The remaining 37 probands were screened for mutations in all three collagen IX genes and in the COMP gene. The probands with talipes deformities or multipartite patella were also screened for the R279W mutation in DTDST. The analysis resulted in identification of three mutations in COMP and one in COL9A1, but none in the other two collagen IX genes. Two of the probands with a multipartite patella had the homozygous DTDST mutation. The results show that mutations in COL9A1 can cause MED, but they also suggest that mutations in COL9A1, COL9A2, COL9A3, COMP, and DTDST are not the major causes of MED and that there exists at least one additional locus.

Management of Double-Layered Patellae by Compression Screw Fixation

Management of Double-Layered Patellae by Compression Screw Fixation

Management of Double-Layered Patellae by Compression Screw Fixation

Tripartite patella is a form of double-layered patella in which the anterior layer is bipartite. It was first described by Büttner in 1925 (1). More recently, an association with multiple epiphyseal dysplasia has been described (2,3). In this article, we describe a case of symptomatic tripartite patella in a 13-year-old child who was subsequently found to have features of multiple epiphyseal dysplasia. Her patellae had an abnormal excursion with a click and a visible jump in the longitudinal line of movement, but no lateral instability. We present a surgical solution not previously described by fusion of the two main components and report an excellent result.

Double-Layered Patella in Multiple Epiphyseal Dysplasia: A Valuable Clue in the Diagnosis

Bilateral double-layered patella, a form of partite patella consisting of anterior and posterior components, was diagnosed in three children with multiple epiphyseal dysplasia. The literature on double-layered patella, its relationship to multiple epiphyseal dysplasia, radiographic findings, and clinical implications are reviewed.

Findings at Arthrotomy in a Case of Double Layered Patellae Associated with Multiple Epiphyseal Dysplasia

Findings at Arthrotomy in a Case of Double Layered Patellae Associated with Multiple Epiphyseal Dysplasia