DISLOCATION OF HIP PROSTHETIC IMPLANT

Introduction

After aseptic loosening, dislocation of hip prosthesis is the most frequent complication in patients with hip arthroplasty, with annual cost of treatment from 70 to 100 million dollar (American estimation)

Materials and methods

In the periods between January 2000 and December 2005, 359 hip arthroplasty surgeries were done in orthopedic clinic of Torretti Hospital of Ancona – Italy as following: 279 cases of primary hip arthroplasty and 80 cases of revision hip prosthesis with rate of dislocation: Total number of cases are 24 from 359 (6.6%) cases as following: 15 cases (5,3%) after primary hip arthroplasty and with rate of dislocation 9 cases (11,2%) after revision hip arthroplasty, all the dislocated case are followed retrospectively as following:

1. -

   We analyzed our data according to the followings

2. -

   Primary pathologies in the dislocated hip cases

3. -

   Models of prosthesis that have been implanted (ABG II, Doufit SAMO, Ancafit Cremascoli)

4. -

   Causes of dislocation and time of dislocation regarding the date of operation

5. -

   Types of treatment used in dislocated cases

Conclusion

Concerning to the perioperative complications and risk of factors, our data are accepted to those with similar criteria mentioned in literature.

Some factors (as example, good patient selection, good preoperative planning, good experience of the surgeon and regular clinical and radiographic follow up) can favor good results with less complications

The surgical treatment becomes indispensable after second episode of dislocation, especially if the hip is highly unstable after the closed reduction.

The corrected therapeutic choice depends on the determining cause of the dislocation (imbalance of the soft tissues, malposition of the prosthetic components or both) 3

1. -

   Modularity of DOUFIT SAMO Prosthesis is considered as indispensable factor because it is nearly accommodate the anatomy of Hip joint and so can decrease the possibility of hip prosthesis dislocation after both primary and revision hip arthroplasty.

This study emphasizes the need for further researches on the geometry of the hip prosthesis that may lead to decrease the risk of dislocation after hip arthroplasty.