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J Bone Joint Surg Br — eLetters for Zhao et al., 93-B (9) 1189-1193.

Total hip replacement for high dislocated hips without femoral shortening osteotomy: questions 21 December 2011

Z. Deniz Olgun,
Orthopaedic Surgeon
Dortyol State Hospital, Hatay, TURKEY,
Bulent Atilla

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Re: Total hip replacement for high dislocated hips without femoral shortening osteotomy: questions

Email Z. Deniz Olgun, et al.

Sir,

We thank Dr Zhang et al for this report of 74 THRs performed on patients with high hip dislocations without osteotomy. This is a very interesting paper challenging the necessity of a subtrochanteric osteotomy, which delays post-operative rehabilitation, interferes with the primary stability of the femoral component and has been found prone to healing problems. We read it with interest and have several questions regarding this paper.

We feel that the technique for soft tissue release the authors used in order to achieve reduction without shortening was not defined clearly enough in the report. This is our main interest because in some of our high hip dislocation cases, we have found the hamstrings to be so tight that they prevent prosthetic reduction even in the presence of a shortening osteotomy. Further shortening had to be performed and on several occasions we have had to isolate the ischial tuberosity and release the hamstring muscles from their origin. In other patients, tightness of the flexor group along with the iliotibial tract presented a similar difficulty, not only for the reduction of the hip but also acute patellar dislocation which we have observed in two patients when the limb was forced to elongate. This might be because valgus knees and hypoplastic lateral femoral condyles are relatively common in this group of patients. We are very curious about the authors’ techniques for dealing with similar problems.

The position of the extremity after forced reduction is another interesting point. The authors mention keeping the patients’ hips and knees in flexion in order to reduce stretch on the sciatic nerve. However, the report details several femoral nerve palsies and no sciatic nerve palsies. We have a series of 84 THRs performed at our institution with shortening osteotomy where we have observed no sciatic nerve palsy but two transient femoral nerve palsies. We concluded that contrary to the common belief, the femoral nerve is at more risk during this procedure and keeping the knee extended might be a better precaution for the palsy of this particular nerve.

In our aforementioned series, we have also observed three cases where medial acetabular wall fractures with pelvic protrusio occurred at the first follow-up visit (six weeks postoperatively). All three patients were older than 50 years. We thought that the limited bone stock around the acetabulum and deficient bone quality were the reasons for this particular complication and that the periacetabular bone was not able to bear even sub-physiological loading (patients were on crutches with non-weight bearing ambulation). Another observation during our series was that in a considerable number of cases the femoral anteversion was found to be so high that without rotational correction a cementless femoral component could not possibly be inserted in the correct orientation. In our opinion, this is another reason to perform subthrochanteric osteotomy. We would like to have the authors’ comments regarding our concerns.

Z.D. Olgun,
Orthopaedic Surgeon,
B. Atilla,
Dortyol State Hospital,
Hatay, Turkey.