We thank Dr. Chadha for his interest in our research and for giving us an opportunity to respond to his comments. Dr. Chadha stated that one of the prerequisites for valgus osteotomy is that hip adduction should be possible preoperatively. However, one patient in our study who underwent valgus osteotomy had a preoperative hip adduction of 0 degrees and painless mobility and instability of the hip. In paragraph two on page 1017 of our published article, we mention that the best results were achieved when a patient experienced painless mobility and instability of the hip. Even if a patient lacks preoperative hip adduction, the condition can be treated with valgus osteotomy because the adduction usually is increased by hip flexion. Flexion of the proximal segment is needed to treat flexion contracture with extension osteotomy. Finally, a distal varus osteotomy allows the surgeon to move the limb out of excessive valgus perpendicular to the pelvis.

Although one might expect that the lower range of values that was reported for hip flexion, abduction, adduction, and internal rotation should be much higher, our patients presented with the hip range-of-motion measurements that were reported in our article. Most of the patients previously had undergone surgery, and the limitations of mobility might be explained by the scarring that they experienced as a result of previous surgery, infection, or the bony abutment of the femoral neck (in cases of Type-IVa and Type-IVb deformities according to the classification presented by Hunka, et al)(1). Nevertheless, these patients still experienced unstable hips with antalgic gait and were helped by this surgical intervention. We look forward to reading about Dr. Chadha’s large experience.

We agree that this procedure, in principle, is not expected to increase the range of motion of the hip but rather to place the arc of motion into a more efficient zone. The main goals of this procedure are to improve hip biomechanics, correct the limb deformity, equalize limb length, and level the pelvis. The study was a retrospective review, and the range-of-motion measurements were based on chart review. Most of the patients experienced correction of the external rotation deformity after internal rotation was performed at the proximal osteotomy site. The data show the range of all patients in the group, not the range of a single patient. The results show a correction of external rotation contracture rather than an increase in range of motion for each patient. Abduction is improved after valgus osteotomy of the proximal femur; an increase in range of motion is therefore not surprising.

Only five patients underwent gait analysis; therefore, we agree that the statistical analysis based on the measurements quoting a p value is of doubtful relevance to our study. We included this information because our standard error of the mean for the measured variables was small and because we performed a paired t test to compare preoperative with postoperative effect in gait. Because our standard error of the mean for the measured variables was small and because we performed a paired t test, we thought that we had adequate statistical power to analyze our data in this fashion.

Reference:

1. Hunka L, Said SE, MacKenzie DA, Rogala EJ, Cruess RL. Classification and surgical management of the severe sequelae of septic hips in children. Clin Orthop. 1982; 171:30-6.

To The Editor:

I read with interest the article "Ilizarov Hip Reconstruction for the Late Sequelae of Infantile Hip Infection"(1). I believe some points need to be clarified by the authors.

Firstly, one of the pre-requisites for valgus osteotomy is that hip adduction should be possible preoperatively. Otherwise, following osteotomy, the patient would not be able to place the foot plantigrade without tilting his/her pelvis. Since the authors mention that the preoperative hip adduction ranged from 0-50 degrees, at least one patient of the 8 reported had no adduction, hence, a valgus osteotomy should not have been indicated in that case.

Secondly, the cases included by the authors were only Hunka(2) grade 4 (4 cases) and grade 5 (4 cases) which implies that the femoral head was absent and only a few hips had a variable length of neck present. Being from a developing country and faced with a large number of patients with a similar presentation secondary to infantile hip infection, our observation has been that most of these cases have an exaggerated range of movement of the hip in all directions especially in Hunka gade 5, the classical ‘Tom Smith arthritis’. However, in the 8 cases reported, the preoperative hip flexion averaged only 94 degrees and a mean hip flexion contracture of 14 degree was reported. One would have expected the range to be much higher in these patients with complete destruction of the head. Only then would a valgus osteotomy be justified to improve stability in an unstable hip.

Thirdly, before surgery the arc of motion from full internal rotation to full external rotation was 50 degrees (10 to 40). Post surgery it had improved to 66 degrees (25 to 41). Also, the preoperative hip abduction ranged from 0-70 while postoperatively it was 30-40 which implies that at least one patient gained 30 degrees of abduction. How do the authors explain the gain in rotation arc and abduction? In my view the total arc of motion should either be the same or may decrease slightly secondary to soft tissue tension/contractures. In any case, I would not expect any improvement in the arc after so many years following infection of the hip.

Fourthly, since the gait analysis was done only for 5 patients, the statistical analysis based on the observations quoting a p value is of doubtful relevance.

Reference:

1. S. Robert Rozbruch, Dror Paley, Anil Bhave and John E. Herzenbert, Ilizarov hip reconstruction for the late sequelae of infantile hip ifection, J.Bone Joint Surg Am. 87:1007-1018, 2005.

2. Hunka L, Said SE, MacKenzie DA, Rogala EJ, Cruess RL. Classification and surgical management of the severe sequelae of septic hips in children. Clin Orthop. 1982; 171: 30-6.

To The Editor:

In the interesting article by Rozbruch, et al, "Ilizarov Hip Reconstruction for the Late Sequelae of Infantile Hip Infection" (2005;87-A:1007-18), the caption for Fig. 2-H on p. 1013 states: "Clinical photograph showing that no Trendelenburg sign is present during single-limb stance."

I would like to point out that even though the patient is fully clothed, it is still obvious that the Trendelenburg sign is present. The patient is standing on her abnormal left lower limb and has sagging of the right buttock; the right iliac crest is lower than the left; and there is a slight shift of the trunk to the left to compensate for the abductor weakness of the left hip.

I have enjoyed reading this article dealing with a difficult problem in paediatric orthopaedics but would like to clarify this important physical sign.

Sharaf Ibrahim, MBChB, FRCS, MS Orth

Department of Orthopaedics and Traumatology,

National University Hospital, Cheras, 56000 Kuala Lumpur, Malaysia.