Distal locking stem for revision femoral loosening and peri-prosthetic fractures

Abstract

Revision total hip arthroplasty in the setting of a large proximal femoral deficiency or a peri-prosthetic fracture remains a challenging problem. We describe the development, surgical technique and the use of cementless revision stems with distal inter-locking screws to provide immediate stability of the femoral implant. Results were assessed in a large multicentre French study conducted with the french hip and knee surgery society (SFHG). We retrospectively reviewed 725 revisions using interlocking stems from 14 French orthopaedic departments. Seven different stems were used in this series. In-patient records were retrieved, and in addition to demographic data the indication for revision, the preoperative and postoperative PMA and Harris hip scores were documented. The bone deficiency was classified on the basis of the French National Orthopaedic Meeting (SOFCOT) classification. Intraoperative complications and problems if any were retrieved from operative notes. Clinical status and radiographs at the final follow-up were evaluated, paying special attention to the metaphyseal filling index. Average follow-up was 4.5 years. As for the clinical results, the mean Harris hip score at last follow-up was 81. Therefore, it increased by an average of 31 points. Bone reconstruction was assessed on the corticomedullary index in the metaphyseal area and at mid-shaft increasing from 36 to 45 and 54 to 63, respectively. Radiologically, 637 implants were stable, and 40 demonstrated subsidence. Forty-eight implants have been revised. We found a significant relation between the metaphyseal filling index, the stability of the stem and the quality of bone reconstruction. Results were analysed with respect to three groups of stems: group 1 was a straight, partially HA-coated implant; group 2 was a curved, fully HA-coated implant; and group 3 was a curved, partially-coated implant. Group 1 showed a significantly higher rate of failure when compared with the others types of implants. Group 2 had better functional results than group 3, which in turn reported better results than group 1. With regard to implant fixation, group 2 had significantly better results. Both groups 2 and 3 induced less thigh pain than group 1. The distal interlocking stem has shown promising results for femoral revisions. The advantages are initial axial and rotational stability and consistent bony ingrowth owing to hydroxyapatite coating. Distal locked stems are mainly indicated to treat complex femoral revision with severe bone loss and peri-prosthetic fractures.

Bilateral synchronous total hip arthroplasty for ankylosed hips

“…(3) To acquire solid fixation, we recommend using extensively coated stems with distal fixation. Mertl P [15] distal locking stem in cases of severe bone loss during revision hip arthroplasty, which achieves an easy and strong initial fixation. (4) Exaggerated femoral anteversion is often seen in these patients.…”

Revision hip arthroplasty using a cementless modular tapered stem

“…This system consists of a distal part, straight or curved, available in different lengths. The curved distal part can also be locked distally with screws, which may be an additional possible advantage in some cases [24]. The proximal part exists also in different lengths and can be connected to the distal part in any position regarding version.…”

“…No patients were lost to follow-up. The study population consisted of 34 male and 39 female patients, with an average body mass index (BMI) of 26 (range [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40]. A bilateral Profemur® R implant was used in three patients.…”

What Are the Causes for Failures of Primary Hip Arthroplasties in France?

“…In particular, distal locking stems, developed in France to address complex femoral revisions secondary to osteolysis or periprosthetic femoral fractures [16], were used in 26% of the cementless femoral implants used for revision. In our study, dislocation was the most common complication reported during the first 3 months after revision surgery, but our 4% rate is quite low in comparison with the usual range (5%-30%) of dislocation after revision THA reported in the literature [19,23].…”