Dislocation After Total Hip Arthroplasty. Mazloumi MD. Patient Risk F actors. Neuromuscular and cognitive disorders Patient noncompliance Previous hip surgery. Surgical Considerations. Approach S oft-tissue tension C omponent positioning Impingement Head size
1- Tensioning or Augmentation of soft tissues
3- Trochanteric advancement
4- Correction of malpositioned of components
5- Improving the head – neck ratio
(P < 0.01).
Woo RY, Morrey BF: Dislocations after total hip arthroplasty. J Bone Joint Surg
Masonis JL, Bourne RB: Surgical approach, abductor function, and total hi arthroplasty dislocation. ClinOrthop2002;405:46-53.
Goldstein WM, Gleason TF, Kopplin M, Branson JJ: Prevalence of dislocation after total hip arthroplasty through a posterolateralapproach with partial capsulotomyand capsulorrhaphy. J Bone Joint Surg Am 2001;86:2-7.
capsule and short external rotators after a posterior approach was shown to reduce dislocation from 4.1% to 0.0% at 1-year followup in a study of 395 patients.
Pellicci PM, Bostrom M, Poss R: Posterior approach to total hip replacement using enhanced posterior soft tissue repairClinOrthop 1998;355:224-228.
(>64 mm cap <26 mm head )
Lewinnek GE, Lewis JL, Tarr R, Compere CL, Zimmerman JR: Dislocations after total hip-replacement arthroplasties. J Bone Joint Surg Am 1978;60:217- 220.
Polyethylene wear increases with larger heads and thinner liners, and wear leads to periprostheticosteolysis and the potential for loosening.
B, Elevated rim.
Hedlundh U, Ahnfelt L, HybbinetteCH, Weckström J, Fredin H: Surgical experience related to dislocations after total hip arthroplasty. J Bone Joint Surg Br 1996;78:206-2
Problems with soft-tissue tension :
1- muscle weakness.
2- inadequate capsular healing and scarring.
3- component malposition.
5- patient noncompliance.
Late dislocations (beyond 1 year)
may suggest :
1- stretching of the soft tissues
2- polyethylene wear.