Incidence, risk factors and prognosis of transient pseudosubluxation after total hip arthroplasty

Abstract

Our results provide information about the incidence, risk factors and natural history of pseudosubluxation after primary THA. Surgeons should be aware of the risk of pseudosubluxation when performing THA in patients with coxa vara, who have a large femoral offset, and in those with dysplastic or deficient acetabulum, who have a lateral centre of rotation.

Increased Postoperative Pseudosubluxation after Total Hip Arthroplasty: A Complication Accelerated by the COVID-19 Pandemic

“…They theorized that iatrogenic loss of native hip offset resulted in capsular laxity, predisposing patients to pseudosubluxation. 5 Our series highlights the unpredictable nature of postoperative pseudosubluxation after primary THA. The incidence of this complication at our institution was 0.14% after transitioning to NA in response to COVID-19.…”

“…4 While performing a closed reduction does confer a small risk of complications, this must be weighed against the odds that spontaneous reduction will quickly occur and not delay the patients' ability to mobilize. 4,5,17 Similar to Cha et al, most surgeons at our institution elected to reduce the prosthetic joint subluxations as rapidly as possible with immediate fluoroscopic confirmation of reduction. 5 In comparison to watchful waiting, rapid closed reduction accelerates patients' postoperative rehabilitation and provides the opportunity to obtain supplementary clinical or radiographic information if indicated.…”

“…4 In contrast, others have since implicated surgical changes in static hip stabilizer tension as a cause of this phenomenon. 5 Cha et al compared 964 primary THA performed under spinal anesthesia to 64 primary THA performed under general anesthesia through either a posterolateral or lateral approach and reported a 3% versus 0% rate of pseudosubluxation in the spinal and general cohorts, respectively. The authors found that decrease of femoral offset, excessive acetabular cup medialization, and preoperative coxa vara femoral anatomy were associated with higher risk of pseudosubluxation.…”

“…Our results are similar to the findings by Cha et al where they found the mean iatrogenic decrease in hip offset in their pseudosubluxated cohort to be 2.2 mm (range -28 to 5). 5 Certainly, this loss of offset may have predisposed these patients to pseudosubluxation due to capsular and soft tissue laxity; however, a difference of 2 mm in offset is within the margin of error even when performing robotic-assisted THA. 15,16 Intentionally increasing offset from native hip values carries the theoretical risk of trochanteric bursitis and has not been shown to guarantee protection from this phenomenon of pseudosubluxation.…”

A novel positioner for accurately sitting the acetabular component: a retrospective comparative study

“…The position of COR following THA is an essential factor that affects the clinical outcomes and longevity of prosthesis [17]. Malposition of RCH may eventually lead to pseudosubluxation [18]. Superior or lateral placement of the cup as a risk factor may result in aseptic loosening of the implants, discrepancy of the leg, bony impingement, and decreased abductor muscle tension [19–21].…”