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Medial Acetabular Wall Breach in Total Hip Arthroplasty - Is Full-Weight Bearing Possible?


Mandelli, Filippo; Tiziani, Simon; Schmitt, Jürgen; Werner, Clément M L; Simmen, Hans-Peter; Osterhoff, Georg (2018). Medial Acetabular Wall Breach in Total Hip Arthroplasty - Is Full-Weight Bearing Possible? Orthopaedics & Traumatology, Surgery & Research (OTSR):Epub ahead of print.

Abstract

BACKGROUND A breach of the medial acetabular wall is a phenomenon seen frequently due to over-reaming during total hip arthroplasty (THA). The consequences of this issue are not fully understood particularly in cementless THA. A retrospective study was performed to answer whether: 1) immediate postoperative full-weight bearing in the presence of a medial acetabular wall breach after THA results in more short-term revisions of the acetabular component, 2) increases the risk for migration of the acetabular component?
HYPOTHESIS Immediate full-weight bearing in the presence of a medial breach is not associated with an increased likelihood for acetabular-related revision surgery or migration of the cup.
PATIENTS AND METHODS In this retrospective cohort study, consecutive patients (n=95; mean age 68±13 years; 67 female) who underwent THA with an uncemented acetabular component were identified and a retrospective chart review was performed (follow up 23±17 months, range 6 to79 months). The presence of a postoperative radiographic medial acetabular breach was documented and the need for revision surgery and the rate of acetabular component migration were assessed during follow-up.
RESULTS Some extent of radiographic medial acetabular wall breach was seen in 26/95 patients (27%). With regard to the primary outcome, 2/95 patients (2%) required revision surgery during follow up. All revision surgeries occurred in the group without a medial breach (p=0.280) for causes related to the femoral or the head components. Persistent pain was present in 1/26 patients (3.8%) in the medial breach group and 8/69 patients in the control group (11.6%; p=0.436). In the radiographic follow up (n=81), there was no significant difference between the control group and the medial breach group with regard to cup migration (Δ ilio-ischial overlap (distance between the ilio-ischial line and a parallel line tangential to the acetabular cup on AP views): -0.5±0.9mm (range, -2.9 to 0.8) vs. -0.3±1.7mm (range, -1.9 to 2.2), Δ overlap tangent (defined as the distance between the two crossings of ilio-ischial line and the acetabular component on AP views): -2.2±6.1mm (range, -21.4 to 0.0) vs. 0.4±6.9mm (range, -6.2 to 17.6)). Similarly, according to variation in the ilio-ischial overlap distance between post-operative and follow-up on pelvic AP views, 0/56 hips (0%) had cup migration ≥ 5mm in the control group versus 1/25 (4%) in the medial breach cohort (p = 0.3).
DISCUSSION In this retrospective observation of patients with immediate postoperative full-weight bearing after THA, a radiographic breach of the medial acetabular wall was not associated with an increased risk for short-term revision surgery or radiographic migration at follow-up. According to the findings of this study and in the light of previous biomechanical studies, there is no clear evidence for postoperative partial-weight bearing in case of a medial breach as far as the surgeon feels that the acetabular component is stable.

Abstract

BACKGROUND A breach of the medial acetabular wall is a phenomenon seen frequently due to over-reaming during total hip arthroplasty (THA). The consequences of this issue are not fully understood particularly in cementless THA. A retrospective study was performed to answer whether: 1) immediate postoperative full-weight bearing in the presence of a medial acetabular wall breach after THA results in more short-term revisions of the acetabular component, 2) increases the risk for migration of the acetabular component?
HYPOTHESIS Immediate full-weight bearing in the presence of a medial breach is not associated with an increased likelihood for acetabular-related revision surgery or migration of the cup.
PATIENTS AND METHODS In this retrospective cohort study, consecutive patients (n=95; mean age 68±13 years; 67 female) who underwent THA with an uncemented acetabular component were identified and a retrospective chart review was performed (follow up 23±17 months, range 6 to79 months). The presence of a postoperative radiographic medial acetabular breach was documented and the need for revision surgery and the rate of acetabular component migration were assessed during follow-up.
RESULTS Some extent of radiographic medial acetabular wall breach was seen in 26/95 patients (27%). With regard to the primary outcome, 2/95 patients (2%) required revision surgery during follow up. All revision surgeries occurred in the group without a medial breach (p=0.280) for causes related to the femoral or the head components. Persistent pain was present in 1/26 patients (3.8%) in the medial breach group and 8/69 patients in the control group (11.6%; p=0.436). In the radiographic follow up (n=81), there was no significant difference between the control group and the medial breach group with regard to cup migration (Δ ilio-ischial overlap (distance between the ilio-ischial line and a parallel line tangential to the acetabular cup on AP views): -0.5±0.9mm (range, -2.9 to 0.8) vs. -0.3±1.7mm (range, -1.9 to 2.2), Δ overlap tangent (defined as the distance between the two crossings of ilio-ischial line and the acetabular component on AP views): -2.2±6.1mm (range, -21.4 to 0.0) vs. 0.4±6.9mm (range, -6.2 to 17.6)). Similarly, according to variation in the ilio-ischial overlap distance between post-operative and follow-up on pelvic AP views, 0/56 hips (0%) had cup migration ≥ 5mm in the control group versus 1/25 (4%) in the medial breach cohort (p = 0.3).
DISCUSSION In this retrospective observation of patients with immediate postoperative full-weight bearing after THA, a radiographic breach of the medial acetabular wall was not associated with an increased risk for short-term revision surgery or radiographic migration at follow-up. According to the findings of this study and in the light of previous biomechanical studies, there is no clear evidence for postoperative partial-weight bearing in case of a medial breach as far as the surgeon feels that the acetabular component is stable.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Hospital Zurich > Department of Trauma Surgery
Dewey Decimal Classification:610 Medicine & health
Language:English
Date:13 June 2018
Deposited On:19 Jun 2018 10:45
Last Modified:31 Jul 2018 07:13
Publisher:Elsevier
ISSN:1877-0568
OA Status:Closed
Free access at:Publisher DOI. An embargo period may apply.
Publisher DOI:https://doi.org/10.1016/j.otsr.2018.04.020
PubMed ID:29908355

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