Key diagnostic factors

presence of risk factors (common)

• Key risk factors for joint dislocation are sports-related activities, loose ligaments, Ehlers-Danlos syndrome, males between adolescence and 40 years of age (shoulder and finger), women 61 to 80 years of age (shoulder), prior history of joint instability, skeletal or muscular dysplasia (patella), high Q angle (patella), external tibial torsion (patella), and patella alta.

characteristic posturing of joint (common)

• Anterior shoulder dislocations present with the arm in a characteristic position of external rotation and slight abduction. Posterior shoulder dislocations present with the arm held in adduction and internal rotation; the shoulder cannot be externally rotated, either actively or passively. Inferior shoulder dislocations present with the arm fully abducted and elbow commonly flexed on or behind the head.
• Patellar dislocation often presents with a swollen knee held in flexion with an obvious lateral prominence.
• Elbow dislocation typically presents with the elbow held in flexion.

pain (common)

• Typically, patients have significant pain on movement and are significantly apprehensive about motion of the affected joint.

inability to move joint (common)

• Patients are usually unable to move the joint or have incomplete range of motion.

tenderness (common)

• Patients have tenderness around the dislocated joint.

swelling (common)

• Patients often present with varying degrees of oedema around the dislocated joint.

normal neurological function of shoulder and elbow (common)

• Should be established by assessing the function of the radial, ulnar, median, and axillary nerves. If function is abnormal, the patient should be referred to an orthopaedic specialist.

cruciate ligament injury with patellar dislocation (common)

• May accompany patellar dislocation.
• If pain permits, the physician should perform a full knee examination to determine concomitant injury to other ligamentous structures (e.g., anterior/posterior draw and Lachman's tests to examine cruciate ligaments).

meniscal tears with patellar dislocation (common)

• May accompany patellar.
• McMurray's test can be used to evaluate for meniscal tears in patients with patellar dislocation.

ligamentous injuries of the knee with patellar dislocation (common)

• May accompany patellar dislocation.
• Varus and valgus stress testing can be used to evaluate the function of various knee ligaments.

patellar or quadriceps tendon rupture with patellar dislocation (common)

• May accompany patellar dislocation.
• The patient should demonstrate the ability to perform a supine straight leg raise to exclude rupture of these structures. [11] [19] [27] [28]

Other diagnostic factors

ecchymosis with finger dislocation (common)

• Finger dislocations may be accompanied by ecchymosis (bruising).

haemarthrosis with patellar dislocation (uncommon)

• Bleeding into joint spaces may occur with patellar dislocation.