Down syndrome (DS), is a genetic disorder caused by a third copy of the 21st chromosome (Trisomy 21), featuring typical facial characteristics, growth delays and varying degrees of intellectual disability. Some degree of immune deficiency is variably present. Multiple orthopaedic conditions are associated, including stunted growth (90%), ligamentous laxity (90%), low muscle tone (80%), hand and foot deformities (60%), hip instability (30%), and spinal abnormalities including atlanto-axial instability (20%) and scoliosis. Hip disease severity varies and follows a variable time course. Rarely a child presents with DDH, but during the first 2 years the hips are characteristically stable but hypermobile with well-formed acetabulae. Spontaneous subluxation or dislocation after 2 presents with painless clicking, limping or giving way. Acute dislocation is associated with moderate pain, increased limp and reduced activity following minor trauma. Hips are reducible under anesthesia, but recurrence is common. Eventually concentric reduction becomes rarer and radiographic dysplasia develops. Pathology includes: a thin, weak fibrous capsule, moderate to severe femoral neck anteversion and a posterior superior acetabular rim deficiency. A number of femoral and acetabular osteotomies have been reported to treat the dysplasia, with acetabular redirection appearing to be most successful. However, surgery can be associated with a relatively high infection rate (20%). Additionally, symptomatic femoral head avascular necrosis can occur as a result of slipped capital femoral epiphysis. Untreated dysplasia patients can walk with a limp and little pain into the early twenties even with fixed dislocation. Pain and decreasing hip function is commonly seen as the patient enters adult life. Occasionally the hip instability begins after skeletal maturity. Total hip arthroplasty (THA) is the standard treatment when sufficient symptoms have developed. The clinical outcomes of 42 THAs in patients with Down syndrome were all successfully treated with standard components. The use of constrained liners to treat intra-operative instability occurred in eight hips and survival rates were noted between 81% and 100% at a mean follow-up of 105 months (6 – 292 months). A more recent study of 241 patients with Down syndrome and a matched 723-patient cohort from the Nationwide Inpatient Sample compared the incidence of peri-operative medical and surgical complications in those who underwent THA. Compared to matched controls, Down syndrome patients had an increased risk of complications: peri-operative (OR, 4.33; P<.001), medical (UTI & Pneumonia OR, 4.59; P<.001) and surgical (bleeding OR, 3.51; P<.001), Mean LOS was 26% longer (P<.001). While these patients can be challenging to treat, excellent surgical technique and selective use of
Down’s syndrome is associated with a number of
musculoskeletal abnormalities, some of which predispose patients
to early symptomatic arthritis of the hip. The purpose of the present
study was to review the general and hip-specific factors potentially
compromising total hip replacement (THR) in patients with Down’s
syndrome, as well as to summarise both the surgical techniques that
may anticipate the potential adverse impact of these factors and
the clinical results reported to date. A search of the literature
was performed, and the findings further informed by the authors’
clinical experience, as well as that of the hip replacement in Down
Syndrome study group. The general factors identified include a high
incidence of ligamentous laxity, as well as associated muscle hypotonia
and gait abnormalities. Hip-specific factors include: a high incidence
of hip dysplasia, as well as a number of other acetabular, femoral
and combined femoroacetabular anatomical variations. Four studies
encompassing 42 hips, which reported the clinical outcomes of THR
in patients with Down’s syndrome, were identified. All patients
were successfully treated with standard acetabular and femoral components.
The use of supplementary acetabular screw fixation to enhance component
stability was frequently reported. The use of constrained liners
to treat intra-operative instability occurred in eight hips. Survival
rates of between 81% and 100% at a mean follow-up of 105 months
(6 to 292) are encouraging. Overall, while THR in patients with
Down’s syndrome does present some unique challenges, the overall
clinical results are good, providing these patients with reliable
pain relief and good function. Cite this article:
