Acetabular rotation by triple pelvic osteotomy according to Tönnis

Abstract

Lesions of the acetabular labrum should be treated by correcting the causes. In a steep acetabulum where the femoral head brings the acetabular labrum under tension and traction, the acetabulum should be rotated by triple pelvic osteotomy to slightly over-corrected acetabular measurements. Severely diminished acetabular and femoral anteversion can also lead to tears and impingement of the labrum. Then rotation of the femoral neck and/or rotations of the acetabulum by triple osteotomy to 15-20 degrees of anteversion are indicated. Our triple osteotomy technique differs from that of others mainly in the ischial osteotomy. It is performed from the posterior approach between the sciatic notch next to the ischial spine and the obturator foramen and is directed 20-30 degrees anteriorly from the frontal (coronal) plane. The osteotomies therefore are placed close enough to the acetabulum to allow free rotation, but they do not interfere with the circulation of the acetabulum, and the ligaments between the sacrum and ischium are left in normal tension. Our normal values of the acetabular position were tested by correlating the measurements with the absence of pain. The optimum is reached with a CE angle and a VCA angle of 30-35 degrees, an angle of the weight-bearing zone of +5 to -5 degrees and a migration index of 10-15%. Overcorrections again caused pain and should be avoided. Diminished anteversion of femur and acetabulum towards 0 degree also caused pain and should be corrected by triple and femoral osteotomy to 15-20 degrees of anteversion. In earlier follow-ups of 216 hips 5-10 years postoperatively, 82.3% of the joints showed no change in the degree of osteoarthrosis. Survival rate curves regarding the absence of pain demonstrated that pain was experienced again when joints were corrected insufficiently or overcorrected, while in good corrections the joints were free of pain in about 75%.

Does Previous Hip Surgery Effect the Outcome of Tönnis Triple Periacetabular Osteotomy? Mid-Term Results

“…The osteotomies of ischium, pubis, and ilium are close enough to the hip joint to allow satisfactory rotation of the acetabulum. 16 There are many papers about the TPAO surgery reporting improved femoral head coverage, decreased acetabular inclination, and also an improvement in hip pain and function scores. 17–19 …”

Quadruple and juxta-articular pelvic osteotomy in children using anterior approach: technique and results

“…The greater the mobilization of the acetabulum, the greater is the defect at the osteotomy and nonunion incidence. This complication reported by many authors in Tonnis osteotomy 1.2% in [18], 14% in [14], 28% in [20], and in Carlioz osteotomy 11% in [16], could be minimized by osteotomy of the ischium in the oblique frontal plane [21], and by a decrease of the external rotation of the acetabular fragment. Despite these measures, however ischial nonunion could still occur.…”

Triple osteotomy of the pelvis for acetabular dysplasia

“…This is in accordance with several studies where good results were found after different pelvic osteotomies. 10,11,13,[20][21][22] On the other hand, Peters et al, 23 in a follow-up study nine years after 60 triple osteotomies, found that 27% had received a total hip replacement and another 27% were considered failures. Experience with the Bernese osteotomy showed that 49 of 75 hips required revision.…”

“…29 In retrospect, one has to consider whether a more aggressive approach towards treating this complication might have improved the outcome in our patients. Alternatively, the method of screw and wire fixation of the pubis as described by Tönnis et al, 13 and the method of K-wire fixation of the iliac osteotomy and the mobilisation protocols used at our institution should be critically reviewed. However, in all of the patients it was either the pubic or ischial osteotomy which developed a nonunion, and these osteotomy sites are not fixed by many authors, among them Tschauner et al 27 who reported a very low rate of nonunions.…”