SPECIFIC JOINTS IN JIA
Cervical spine involvement occurs more often in children with JIA than adults. Restriction of ROM, pain, and muscle spasms, which may present as torticollis, may be seen.
A soft cervical collar to serve as a reminder for proper alignment and provide warmth may be helpful in acute pain with muscle spasm. Minimizing time in flexion is important. If the transverse ligament becomes weakened, atlantoaxial subluxation can occur. If subluxation occurs, a firm cervical collar should be worn during automotive transport.
Temporomandibular Joint (TMJ)
This joint is affected in almost two-thirds of children with JIA (117) by causing pain in chewing and opening the mouth, stiffness, and micrognathia. Younger children will not complain of jaw pain, but will instead choose to modify their diet to avoid pain. Progressive jaw ROM exercises and modalities may help treat pain and stiffness. If the lower jaw does not develop properly, it may create an overbite, requiring orthodontist intervention and/or oral surgery. Mandibular and facial growth disturbances are more common in polyarticular types of JIA.
The shoulder is not commonly involved at the onset of disease. Approximately one-third of children with polyarticular or psoriatic disease may eventually develop shoulder involvement and loss of adduction and internal rotation affecting midline ADLs, such as grooming and toileting. The elbow requires at least 90 degrees of flexion range to perform ADLs such as eating, grooming, and reaching. Loss of more than 45 degrees of elbow extension limits the use of arms as levers to rise from a seated position and makes toileting and lower extremity dressing difficult. Wrist involvement is common in children; there is early loss of wrist extension with progressive flexion contracture. A nighttime resting wrist splint can maintain the wrist in 15 to 20 degrees of extension with the fingers in a few degrees of flexion; ulnar deviation can also be built in as necessary. Strengthening of wrist extensors and radial deviators is necessary to reduce wrist flexion and ulnar deviation contractures. Moist heat to reduce spasm and improve tissue elasticity followed by serial casting for 48 to 72 hours as tolerated may help reduce contractures by slowly increasing wrist extension while controlling ulnar deviation and subluxation; commercially available dynamic splinting may also facilitate stretching. Should ankylosis be inevitable, the hand should be splinted in a neutral position for optimal function in self-care.
Functional grasp may become limited as fingers lose both flexion and extension range. Flexion contractures of the metacarpal and PIP joints are often seen. The use of ring splints in metal or plastic can help control PIP flexion and extension seen in boutonniere and swan neck deformities, respectively. Fingers can be strengthened through play with clay and various adaptive putties.
In the lower extremities, flexion contractures occur at the knee and hip. Painful ambulation can lead to increased sitting, which in turn leads to increased flexion contracture, deconditioning, weakness, atrophy, and osteoporosis. Hip flexion contractures in children occur with internal rotation and adduction, compared with adults who tend to develop external rotation and abduction. Prone lying greater than 20 minutes per day with the hips and knees extended and feet off the edge of the bed can help prevent these contractures. Other strategies include strengthening of the hip extensors, external rotators, abductors, and quadriceps, along with ROM exercises to stretch the hip flexors, internal rotators, adductors, and hamstrings. Hip extensors can be strengthened through swimming, aquatic therapy, and bicycling. Encouraging upright posture and ambulation, using a stander as necessary, is also helpful. Hip development may be assisted by the use of a stander; a prone stander can strengthen neck and hip extensors, while a supine stander maintains the knees in extension and allows upright weight-bearing.
The knee is the most commonly affected joint in JIA; early involvement of the knee can cause quadriceps weakness that may not resolve. Knee contractures can lead to other joint contractures and further gait abnormalities. Bony overgrowth with resultant leg-length discrepancies (LLDs) is often seen. The knee can be maintained in extension using resting splints such as knee immobilizers and alternating legs every night as needed to increase comfort and compliance. Dynamic splinting using an adjustable knee joint can be used to improve ROM and limit excessive flexion and valgus tendency. Because forced extension of the knee with a contracture can exacerbate posterior subluxation, caution must be exercised in using bracing and splinting. Active quadriceps strengthening should be done post brace removal and also maintained with knee extension exercise or isometric exercises if too painful. Kicking, bicycling, and walking can also strengthen weak quadriceps muscles.
Multiple foot deformities can occur in JIA, including claw toe, valgus or varus hindfoot, and ankle plantarflexion contracture deformities. The mid-foot is frequently affected, and can be quite painful and difficult to treat. Tenosynovitis that is difficult to discern from joint disease may occur. Molded foot orthoses can be used to reduce pain at the metatarsal heads and heels with weight-bearing. A University of California at Berkeley orthosis can prevent or control varus and valgus deformities. A posterior leaf-spring ankle foot orthosis (AFO) or nighttime resting splint may be helpful to reduce loss of ankle dorsiflexion range and control varus and valgus. Ankle rotation exercises, balancing exercises, and raising the heel on a step can strengthen ankle muscles. Footwear should be comfortable and accommodate any foot deformities. High heels should generally be avoided, as they can help develop plantarflexion contractures and add to foot deformities. Flip-flops should also be avoided secondary to their lack of adequate support.
Inflammation causing bony overgrowth at the distal femur can cause a true LLD, leading to pelvic asymmetry and scoliosis. The increased blood flow from inflammation may alternatively cause early epiphyseal closure and overall limb shortening.