Joint Subluxation and Dislocation

► [Partial (subluxation) or complete (dislocation) loss of contact between two osseous surfaces that normally articulate]

Joint subluxation and dislocation can be present at birth or occur later in life; can be inherited or acquired; can involve one joint or multiple joints; and can occur as an isolated anomaly or as part of a malformation syndrome or bone dysplasia.

Congenital single joint dislocation or subluxation occurs in a number of syndromic and nonsyndromic conditions and is therefore of little help in diagnosis. The subjects of patellar dislocation, atlantoaxial instability and dislocation, and developmental hip dys-

Congenital Radial Hypoplasia
Fig. 8.8. Congenital dislocation of the radial head in an adult male patient. There is anterior radial head dislocation, and slight hypoplasia of distal ulna at the carpus. The anomaly was an isolated, unilateral finding

plasia have been addressed in specific sections in this book. Other single joint dislocations are briefly discussed in this chapter.

Congenital dislocation of the radial head is a well-recognized entity occurring either as an isolated anomaly (uni- or bilateral) or in association with other congenital abnormalities, particularly in the hands (Kelly 1981; Campbell et al. 1992) (Fig. 8.8). Both anterior and posterior dislocation are possible, either resulting in decreased elbow motion (Agnew and Davis 1993). Hypoplasia of the proximal end of the radius, a relatively short ulna, a defective trochlea, and prominence of the ulnar epicondyle are among the abnormalities that may be seen on radiograms. Dislocation of the radial head can occur as a component of any of several syndromes, including nail-patella syndrome (OMIM 161200), oto-palato-digital syndrome (OMIM 311300), Noonan syndrome (OMIM 163950), tarsal/carpal coalition syndrome (OMIM 186570), and ophthalmomandibu-lomelic dysplasia (OMIM 164900) (McKusick). It can also occur as part of auriculo-osteodysplasia (OMIM 109000), an autosomal dominant condition with characteristic ear shape (abnormal attachment of an elongated lobe, accompanied by a small, slightly posterior lobule), dysplasia of the radiocapitellar joint, and short stature. Hip dysplasia and abnormalities of the distal radius are inconstant features (Beals 1967). A special type of congenital radial head dislocation, posterior (OMIM 179200) has been observed in several members of the same family (Cockshott and Omololu 1958; Abbott 1892). An association with antecubital pterygium has been recognized (Shun-Shin 1954). Recessive inheritance is likely, with instances of male-to-male transmission (Reichenbach et al. 1995). Rotation at the elbow is more compromised than extension. Congenital dislocation of the knee is a very rare anomaly accounting for approximately an estimated 1 % of cases of congenital dislocation of the hip. Blacks are affected more frequently than whites, and females three times more frequently than males. Several causes have been proposed, including aberrant fetal position, breech delivery (Johnson et al. 1987), muscular imbalance (Jacobsen and Vopalecky 1985), and defective cruciate ligaments (Katz et al. 1967),but none has been substantiated. Genetic factors are certainly important, as also demonstrated by the occurrence of familial cases (Callahan et al. 1985; Collins et al. 1995). The anomaly consists in partial or total anterior dislocation of the tibia with respect to the femur, resulting in hyperextension with limited flexion capabilities of the knee, and valgus deformity. Shortening of the quadriceps femoris tendon, a tight anterior articular capsule, and hypoplasia of the suprapatellar bursa take place on a secondary basis (Ooishi et al. 1993). Anterior tibial bowing (genu recurvatum) and patellar hypo-plasia can also occur. Dislocation of the knee can be isolated or occur in association with other joint dislocations, spinal anomalies, and foot anomalies (Fer-nandez-Palazzi and Silva 1990). Congenital displacement of a single vertebral body can also occur. Acute dislocation, often after a trivial trauma, is accompanied by sudden onset of neurological deficits. In other cases, neurological abnormalities appear gradually and tend to worsen over time (Shapiro and Herring 1993).

Multiple congenital joint dislocations occur in a selected group of systemic disorders and are therefore of great diagnostic importance. The archetype of these disorders is Larsen syndrome (OMIM 150250, 245600) (Larsen et al. 1950), a heterogeneous condition with either an autosomal dominant or a recessive pattern of inheritance and possible instances of parental germ-line mosaicism (Petrella et al. 1993; Frints et al. 2000). Although this syndrome is discussed in a separate section in this book, a few comments are appropriate here. Features in this syndrome include a specific flat face with widely spaced

There Jacobsen Syndrome Gene

Fig. 8.9. Larsen syndrome in a 3-month-old girl. Observe congenital bilateral luxation of the elbows, knees and hips; equino-varus deformity of the feet; relative shortening of the limbs; prominent abdomen; and flat face with hypertelorism and depressed nasal bridge. (From Weisenbach and Melegh 1996,)

Fig. 8.9. Larsen syndrome in a 3-month-old girl. Observe congenital bilateral luxation of the elbows, knees and hips; equino-varus deformity of the feet; relative shortening of the limbs; prominent abdomen; and flat face with hypertelorism and depressed nasal bridge. (From Weisenbach and Melegh 1996,)

eyes and prominent forehead; bilateral anterior dislocation of the tibia on the femur at the knees, clubfoot, and other joint dislocations, including the hips, the elbows, and the atlantoaxial joint (Fig. 8.9); and other skeletal anomalies, including accessory car-pals, short metacarpals and terminal phalanges, cylindrically shaped fingers, a juxtacalcaneal accessory bone - a feature that is possibly specific for this disorder (Latta et al. 1971), - and cervical spinal abnormalities (Le Marec et al. 1994; Weisenbach and Melegh 1996). Complications secondary to dislocation of the cervical spine can be fatal (Laville 1994; Johnston et al. 1996). The phenotype of the dominant and recessive types is similar, with a less striking 'moon face' and more frequent occurrence of syn-dactyly, cleft palate, genital anomalies, severe short stature, and increased mortality from cardiac and respiratory complications in the recessive form (Strisciuglio et al. 1983). Joint hyperlaxity is characteristic of the disease (Rodriguez et al. 1994), raising the possibility that a gene involved in collagen pro duction might be implicated (Pierquin et al. 1991). In the autosomal dominant Larsen syndrome, the gene maps to 3p21.1-p14.1, a locus which is close to, but distinct from, the COL7A1 locus (OMIM 120120) (Vujic et al. 1995). The fibrillar collagen genes COL1A1 (OMIM 120150), COL1A2 (OMIM 120160), COL3A1 (OMIM 120180), and COL5A2 (OMIM 120190), have been excluded as the site of the mutation in the recessive form of Larsen syndrome (Bonaventure et al. 1992). Furthermore, electro-phoretic analysis of collagens derived from fibroblast cultures have failed to show defective molecules. A lethal disorder closely resembling Larsen syndrome, Larsen-like syndrome, lethal type (OMIM 245650), is characterized by multiple joint dislocations (especially anterior dislocation of both knees), flat face, cleft soft palate, rhizomelic shortening of upper limbs, hypoplastic fibula, laryngotracheomalacia, and pulmonary hypoplasia causing early death (Chen et al. 1982). Whether this disorder is produced by a mutation in a gene distinct from that of the recessive (OMIM 245600) or dominant (OMIM 150250) form of Larsen syndrome is not known (McKusick). Interestingly enough, abnormal collagen bundles in the derma, cartilage matrix, joint capsule, and trachea have been documented on electron microscopy (Clayton-Smith et al. 1988). Desbuquois syndrome (OMIM 251450) is a constellation of severe rhizomel-ic dwarfism manifesting in utero,narrow chest sometimes causing respiratory distress,vertebral and meta-physeal abnormalities, and advanced carpotarsal ossification (Desbuquois et al. 1966; Beemer et al. 1985; Meinecke et al. 1989; Pazzaglia et al. 1988) (Fig. 8.10a,b). Coronal cleft vertebrae may be observed in infants. The proximal femurs are broad, with spurlike projections of the lesser trochanters ('monkey wrench' appearance) (Shohat et al. 1994). Affected patients have glaucoma, mental retardation, and generalized joint laxity with dislocatable knees,hips, and patellae. Although there are recognizable similarities with the Larsen syndrome, the findings in the hands, with supernumerary metacarpal ossification centers causing deviation of the fingers, and the unique appearance of the proximal femoral metaphyses unequivocally identify the Desbuquois syndrome (Le Merrer et al. 1991). Dislocation of multiple joints, together with progressive joint deformities, particularly involving the knees, spine, and hips, are among the cardinal features of spondyloepimetaphyseal dyspla-sia with multiple dislocations (OMIM 603546). Despite joint laxity, this disorder is distinctively different from spondyloepimetaphyseal dysplasia with joint laxity (OMIM 271640), being characterized by

Fig. 8.10 a,b. Desbuquois dysplasia in a 37-week fetus a Postmortem full-body view. There are a relatively large cranium, flat face with micrognathia, small thorax, prominent abdomen, rhizomelic limb shortening and bowing, abnormal hands, and clubfeet. b Postmortem radiograph. The proximal femurs show a unique 'monkey-wrench' appearance. The thorax is bell-shaped, and the ilia are narrow. (From Hall 2001)

Fig. 8.10 a,b. Desbuquois dysplasia in a 37-week fetus a Postmortem full-body view. There are a relatively large cranium, flat face with micrognathia, small thorax, prominent abdomen, rhizomelic limb shortening and bowing, abnormal hands, and clubfeet. b Postmortem radiograph. The proximal femurs show a unique 'monkey-wrench' appearance. The thorax is bell-shaped, and the ilia are narrow. (From Hall 2001)

Radiocapitellar Joint

unique changes in the epiphyses (smallness, flattening, irregularity, fragmentation); in the metaphyses (widening, irregularity, sclerosis); in the hands (gracile metacarpals, long slender phalanges with squared ends, prominent phalangeal tufts, small and irregular carpal bones); and in the spine (posterior scalloping of the lumbar vertebral bodies, end-plate irregularity, craniocaudal narrowing of the inter-pediculate spaces) (Hall et al. 1998). On the other hand, spondyloepimetaphyseal dysplasia with joint laxity is associated with kyphoscoliosis at birth, talipes equinovarus, cleft palate, congenital heart disease, and a specific facial dysmorphism. Multiple dislocations also occur with pseudodiastrophic dysplasia (OMIM 264180), a condition first described by Burgio et al. (1974). With few exceptions (Eteson et al. 1986), this is an early lethal disorder that shares similarities with,but is distinct from, diastrophic dysplasia (OMIM 222600). Rhizomelic shortening of the limbs, severe clubfoot deformity, and atlantoaxial instability are common to both conditions. Distinct features in pseudodiastrophic dysplasia include marked lumbar scoliosis, more severe platyspondyly, tongue-like deformities of the vertebral bodies in the lumbar spine, enlarged bitemporal diameter with midface hypoplasia, and a unique pattern in the hands, with multiple interphalangeal and metacar-pophalangeal joint dislocations and normal appearance of the 1st metacarpal, as opposed to the ovoid, hypermobile, abducted, proximally inserted (hitchhiker) thumb of diastrophic dysplasia. Cartilage histology at the growth plate is also different in dias-trophic dysplasia and pseudodiastrophic dysplasia.

Moreover, the genetics of the two disorders is different. In a similar way to atelosteogenesis type 2 (OMIM 256050) and achondrogenesis type 1B (OMIM 600972), diastrophic dysplasia results from a defect in the sulfate transporter gene DTDST, which encodes a sulfate transporter of the cell membrane (Hastbacka et al. 1994) and is a gene that is not involved in pseudodiastrophic dysplasia (Cetta et al. 1997). The RAPADILINO syndrome (OMIM 266280) is an association of radial aplasia/hypoplasia (RA), patella hypoplasia/aplasia and cleft/high-arched palate (PA), diarrhea and dislocated joints (DI), small size and limb malformations (LI), and long nose and normal intelligence (NO) (Kaariainen et al. 1989; Vargas et al. 1992). Longitudinal radial-ray deficiency (radius and thumb) and patellar aplasia/hypoplasia are the main manifestations of the syndrome. Findings in the face include elongated face, narrow palpe-bral fissures, long slender nose, small chin, and unusual ears. Multiple joint dislocations may occur in association with stiff interphalangeal joints. Multiple joint dislocations (hips, thumbs and great toes) are manifestations of cutis laxa, corneal clouding, and mental retardation (De Barsy syndrome, OMIM 219150), a progeroid disorder with defective development (or synthesis?) of elastic fibers in the skin (de Barsy et al. 1968; Karnes et al. 1992). Affected patients show retarded psychomotor development, hypotonia and athetosis. The corneas are cloudy due to degeneration in the Bowman membrane. The skin is translucent,with unusually obvious superficial blood vessels. A wrinkled face, inguinal hernia, and sclerotic foci in the skeleton are additional findings.

Reports of multiple dislocations in association with metaphyseal dysplasia (Phaoke et al. 1993), 'spondylo-acrodysplasia with severe combined immunodeficiency' (Castriota-Scanderbeg et al. 1997), and short stature and carpal coalition (Steel et al. 1993) have recently been reported.

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  • Zara
    Is there jacobsen syndrome gene?
    7 years ago
  • dehab
    Who recognized nail patella?
    7 years ago
    Can splints help improve bilateral congenital posterior radial head dislocation?
    7 years ago
  • Richard
    What is joint dislocation syndrome?
    7 years ago

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