Joints: Narrowed Joint Space and Ankylosis



10.1055/b-0034-87927

Joints: Narrowed Joint Space and Ankylosis









































Table 5.27 Joints: ankylosis

Diagnosis


Findings


Comments


Postsurgical


Bone bridges prior to joint.


Ankylosis correlates with the locations of fusion; surgical defects and hardware may be present.


Sequelae of septic arthritis


Frank destruction of joint leads to eventual ankylosis.



JIA


Joint space narrowing from cartilage loss leads to ankylosis.


Locations correspond to sites of inflammation.


Infantile cortical hyperostosis (Caffey syndrome)


Smooth interosseous bridging and cortical thickening between long bones (e.g., radius and ulna). Involves diaphysis and spares epiphysis.


Synostosis may occur between two adjacent long bones after resolution of the acute phase.


Radioulnar synostosis


Fig. 5.38


Proximal radius and ulna are fused by a bone bridge.


The trabecular bone between the proximal radius and ulna is continuous.


Isolated


Fig. 5.39a, b




Fibrodysplasia ossificans progressiva


Soft-tissue ossification bridging joints.


Intermittent progressive heterotopic bone replaces skeletal muscle and connective tissues.

Fig. 5.38 Radioulnar synostosis.
Fig. 5.39a, b Isolated ankylosis. (a) Radiohumeral synostosis. (b) US shows a synchondrosis (arrow) where the joint should be located. H Humerus R Radius































Table 5.28 Joints: narrow joint space

Diagnosis


Findings


Comments


QA


Fig. 5.40, p. 522


Cartilage loss, marginal osteophytes, subchondral bone marrow edema, sclerosis, and cysts.


Although typically seen in adults, secondary OA may complicate JIA or the later stages of AVN. Any disorder that causes abnormal m echanics may lead to OA: posttraumatic, after repair of anterior cruciate ligament.


Sequela of septic arthritis


Fig. 5.22, p. 509



Presumably, pyarthrosis increases intracapsular pressure and compromises epiphyseal blood flow. Inflammation contributes to acute cartilage loss.


JIA


Fig. 5.41a, b, p. 522


Joint space narrowing at sites of inflammation. May have imaging findings of synovial thickening and hyperemia, bone marrow edema (MRI), and erosions.


Inflammation contributes to acute cartilage loss.


Hemophilia


Resembles JIA. Epiphyses of affected joints are often enlarged.



Narrowing of the joint space usually results from diseases that cause cartilage loss. A narrowed joint space may be a precursor to ankylosis.

Fig. 5.40 Osteoarthritis. Advanced joint degeneration from slipped capital femoral epiphysis of the left hip with joint space narrowing and osteophyte formation limiting abduction (arrow).
Fig. 5.41a, b Juvenile idiopathic arthritis with diffuse joint space narrowing at both hips (a) that is greater on the right. (b) Corresponding coronal T1-weighted image.






















Table 5.29 Joints: proximal radioulnar synostosis

Diagnosis


Comments


Congenital


Autosomal dominant and sporadic forms.


Associated skeletal anomalies


Developmental dysplasia of the hip, club feet, missing or diminutive thumb, coalescence of carpal bones, symphalangism, and dislocation of radius.


Associated syndromes


Multiple exostoses, acrocephalopolysyndactyly, Holt-Oram, mandibulofacial dysostosis, Nievergelt dysplasia and Apert, Williams, Klinefelter (and other variants of Klinefelter syndrome with extra sex chromosomes), Nievergelt-Pearlman, and fetal alcohol syndromes.


Proximal radioulnar synostosis may arise from a defect in longitudinal segmentation at the seventh week of development and is bilateral in 60% of cases. Surgery is rarely indicated (because bridge regrows) except for severe pronation deformities.

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Jul 12, 2020 | Posted by in PEDIATRIC IMAGING | Comments Off on Joints: Narrowed Joint Space and Ankylosis

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