[Modified Exeter technique in revision hip surgery].
OBJECTIVE
The Exeter technique opened new perspectives for the treatment of femoral bone stock loss in revision hip arthroplasty. Implant migration in the cement sheath is, however, a frequent finding. According to the promoters of the technique, this would favor transformation of the allograft into living bone. For others it is a worrisome problem since it alters the heterogeneous cement sheath, leading to loosening and final surgical revision, with an incidence up to 20%. We propose an analysis of the mid-term results of the modified Exeter technique with the objective of cementing the distal part of the implant directly into the recipient bone in order to achieve satisfactory primary stability. The purpose of this work was to analyze the consequences of this method on the long-term evolution of the allograft.


METHODS
After preparing the femur, a specific gun is filled with allograph dough obtained from frozen femoral heads fragmented with an acetabular reamer. The Mersilene mesh enables the deposit of a tube of graft material at the desired level. The implant is sealed after impaction of the graft to enable direct distal cementing in contact with the recipient bone. Partial weight bearing is allowed as early as the fifth day and increased progressively to complete weight bearing at three months. Forty-five patients (46 hips) were treated between June 1996 and January 2002. Six patients were not retained for analysis due to insufficient follow-up. For three patients, graft outcome could not be properly assessed due to a major complication. In addition, two patients died and one was lost to follow-up. In all 39 patients (40 hips) were analyzed at mean follow-up of 84 months (range 48-110). There were no cases of revision for femoral loosening. Femoral bone loss was mainly moderate to severe type II and III hips (Sofcot classification) but limited in height (no grade IV in the Endo-Klinik classification).


RESULTS
Clinical outcome was excellent in 13 hips, good in 16, fair in nine and poor in two (Postel-Merle-d'Aubigné score). Defective distal cementing with implant migration (less than 5 mm) was noted in four cases followed by secondary stabilization. Transformation of the allograft occurred in 36 cases, associated with corticalization of the recipient bone in 14.


CONCLUSIONS
This technique is reproducible since primary stability was obtained in 90% of hips, without hindering transformation of the allograft. The results, which are sustained over time, are the same as with the princeps technique and no radiographic evidence of stress shielding could be found.
Département Chirurgie-Orthopédique, Institut Mutualiste Montsouris, Paris, France. emmanuel.dethomasson@imm.fr
E
E
de Thomasson
O
O
Guingand
R
R
Terracher
C
C
Mazel
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D005260:Female; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D011474:Prosthesis Design; D012086:Reoperation