gms | German Medical Science

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018)

23.10. - 26.10.2018, Berlin

Instability in total hip arthroplasty for developmental dysplasia

Meeting Abstract

Suche in Medline nach

  • presenting/speaker Jonathan Gómez H. - Hospital Policlínico Roma, San Salvador, El Salvador
  • Ricardo Gómez G. - Hospital Policlínico Roma, San Salvador, El Salvador

Deutscher Kongress für Orthopädie und Unfallchirurgie (DKOU 2018). Berlin, 23.-26.10.2018. Düsseldorf: German Medical Science GMS Publishing House; 2018. DocST36-411

doi: 10.3205/18dkou216, urn:nbn:de:0183-18dkou2162

Veröffentlicht: 6. November 2018

© 2018 Gómez H. et al.
Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). Lizenz-Angaben siehe http://creativecommons.org/licenses/by/4.0/.


Gliederung

Text

Objectives: To determine the risk factors for dislocation in Total Hip Arthroplasty (THA) for Developmental Dysplasia of the Hip (DDH).

Methods: Retrospective multicentric case cohort. Charts and radiographs of 71 patients (85 hips) with arthrosis due to DDH were reviewed. All patients were operated by four surgeons in three centers from 1998 to 2017. The mean follow-up was 7.5 years (range 1-20 years, SD4.3). All procedures were performed throuw a posterolateral approach and implants were selected according to the patient's characteristics and surgeon's preference, but in all cases friction pair were metal on polyetilene and femoral head size 22 or 28 mm. Radiographic analysis was realized by an independent surgeon; it included cup abduction, anteversion (Ackland's formula) and hip center, calculated with Meazure® 2.0 (C-Thing Software). Anatomic rotation center was defined as ≤ 20 mm above from the interteardrop line.

Two cut points were established: 6 months to assess dislocation (all hips) and 48 months for survival rate (74 hips), with revision for other causes rather than instability or infection as ending point. Statistical analysis was completed with GraphPad Prism® 7.02 Software, obtaining Kaplan Meier survivorship and comparing with Mantel-Cox Test and Gehan-Breslow- Wilcoxon test. After assessing normality of Groups with Agustino Pearson test, the dislocation rate was compared between dysplasia type, hip center and femoral head size with Fisher's test, and for continuous variables with T test and one-way ANOVA.

Results and conclusion: The mean age was 44 years (range 24-80, SD 11), 77.4% were females. Sub-trochanteric transverse femoral-shortening was needed in 14 hips, and acetabular augmentation with femoral head autograft in 15 patients. The survival rate was 95% at 13 years. Modified Oxford Hip Score 40.3.

The overall complication rate was 31%, with dislocation (7/85 hips) as leading cause of revision (4/9). All dislocations were in anterior direction, and not related to severity of dysplasia (p=0.40 OR 4.65 IC95%), hip center (p=0.16 OR 2.94 IC95%) or femoral head size (p=0.31, OR 0.5 IC95%). Most the dislocations (5/7) were at inmediate post op period, and we noticed that most of them (5/7) had a cup anteversion of ≥ 10° (p=0.06) (Table 1 [Tab. 1]).

The dislocation is the leading complication in our series, and not related to severity of disease, hip center or femoral head size. There was an increased anteversion in the unstable cases, but the overall dislocation rate was too low to perform a strong statistical correlation.