Soft tissue tension is four times lower in the unstable primary total hip arthroplasty
The aim was to compare patients who suffered recurrent dislocation following total hip arthroplasty (THA) with those who did not to clarify the degree of soft tissue tension in dislocation patients.
The subjects were 18 hips with recurrent dislocation (unstable THA group) and 37 hips without dislocation (stable THA group). To evaluate soft tissue tension, radiographs were taken while applying distal traction at traction forces of 40, 30, and 20% of the body weight (BW) and femoral head displacement was measured. Acetabular offset, femoral offset, limb offset, and leg length discrepancy were measured in patients with a normal contralateral hip joint.
The mean femoral head displacement in the unstable THA group was 5.6 mm at 40% of the BW, 4.6 mm at 30% of the BW, and 3.5 mm at 20% of the BW. In the stable THA group, the mean femoral head displacement was 1.4 mm at 40% of the BW, 1.1 mm at 30% of the BW, and 0.9 mm at 20% of the BW. Significant differences were seen between the groups at all traction forces. Furthermore, on comparing the unstable and stable THA groups, femoral offset was found to significantly be smaller in the affected side than in the healthy side in the unstable THA group.
We found that soft tissue tension is approximately fourfold lower in patients exhibiting recurrent dislocations following THA than in patients exhibiting no dislocations and that femoral offset was related to decreased soft tissue tension.
KeywordsDislocation Soft tissue tension Hip joint Instability Total hip arthroplasty
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. For this type of study, formal consent is not required.
- 14.Marchetti E, Krantz N, Berton C, Bocquet D, Fouilleron N, Migaud H, Girard J (2011) Component impingement in total hip arthroplasty: frequency and risk factors. A continuous retrieval analysis series of 416 cups. Orthop Traumatol Surg Res 97(2):127–133. https://doi.org/10.1016/j.otsr.2010.12.004 CrossRefPubMedGoogle Scholar