Abstract
Background
There are a variety of described osteotomies to address acetabular dysplasia in children with Developmental Dysplasia of The Hip (DDH). This study will analyze the radiographic outcome of cases diagnosed with DDH and treated with a Salter innominate osteotomy.
Methods
A retrospective review of all patients who underwent Salter innominate osteotomy between January 2017 and January 2019 at our institution was performed. 48 procedures (44 patients were evaluated for acetabular index (AI) and center edge angle (CEA) based on the preoperative, immediate postoperative, and the most recent pelvic x-ray.
Results
48 procedures (44 patients) were radiologically evaluated. The AI improved from 34° preoperatively to 19.9° on the final follow up radiograph and the CEA improved from − 2.4° preoperatively to 24.6° on the final follow up radiograph.
Conclusions
In our hands, use of Salter innominate osteotomy for acetabular dysplasia in patients with DDH was associated with good radiological outcomes. The Salter innominate osteotomy was able to improve lateral acetabular coverage of the hip to almost near-normal radiographic values.
Type of Study/Level of Evidence
Therapeutic IV.
Keywords: Developmental dysplasia of the hip, Salter innominate osteotomy, Acetabular dysplasia
Introduction
Many surgical techniques and osteotomies have been described to treat acetabular dysplasia in children and the Salter innominate osteotomy is one of them. This osteotomy was first described by Salter in 1961 and demonstrated reliable correction of the anterolateral acetabular deficiency [1–6].
At our institution, Salter innominate osteotomy has been routinely performed to treat children with acetabular dysplasia in most cases other than neurological cases, for which we use the Dega osteotomy. The purpose of this study is to analyze the radiological outcome of this osteotomy in patients with DDH, specifically regarding acetabular index (AI) and center edge angle (CEA) based on the preoperative, immediate postoperative, and the most recent pelvic x ray.
Methods
After ethical approval from our institution, a retrospective review was performed for all patients who underwent Salter innominate osteotomy between January 2017 and January 2019 at our institution. Patients were Included in the study if they were treated by Salter innominate osteotomy for DDH. Patients were excluded from the study if they underwent Salter innominate osteotomy for acetabular dysplasia related to other diagnosis than DDH. A total of 48 osteotomies on 44 patients were identified that met the study criteria and were considered for inclusion. Surgical indication was acetabular dysplasia in all patients.
Anteroposterior pelvic radiograph was used for measuring the radiographic parameters assessed in our study. AI and CEA were measured preoperatively, postoperatively, and on final follow-up radiographs, Table 2.
Table 2.
Radiographic parameters measured: acetabular index and center edge angle
| Case No | Follow-up (months) | Acetabular index | Center edge angle | ||||
|---|---|---|---|---|---|---|---|
| Pre op | Post op | Final | Pre op | Post op | Final | ||
| 1 | 37 | 35 | 20 | 18 | 13 | 17 | 15 |
| 2 | 33 | 34 | 25 | 20 | − 12 | 14 | 23 |
| 3 | 39 | 36 | 10 | 23 | 14 | 33 | 22 |
| 4 | 43 | 37 | 16 | 15 | 7 | 15 | 18 |
| 5 | 29 | 33 | 18 | 31 | − 17 | 21 | 13 |
| 6 | 36 | 31 | 26 | 21 | 3 | 25 | 16 |
| 7 | 30 | 32 | 14 | 24 | Not Applicable | 32 | 19 |
| 8 | 41 | 30 | 13 | 21 | Not Applicable | 34 | 27 |
| 9 | 42 | 38 | 17 | 16 | Not Applicable | 22 | 14 |
| 10 | 31 | 29 | 15 | 14 | Not Applicable | 9 | 17 |
| 11 | 38 | 38 | 12 | 15 | Not Applicable | 30 | 24 |
| 12 | 32 | 32 | 24 | 23 | Not Applicable | 10 | 21 |
| 13 | 35 | 29 | 21 | 22 | Not Applicable | 31 | 20 |
| 14 | 44 | 31 | 22 | 17 | − 11 | 26 | 26 |
| 15 | 40 | 36 | 19 | 24 | 2 | 13 | 25 |
| 16 | 34 | 30 | 23 | 25 | − 18 | 28 | 22 |
| 17 | 44 | 34 | 11 | 18 | − 12 | 32 | 23 |
| 18 | 31 | 35 | 18 | 19 | − 22 | 25 | 27 |
| 19 | 40 | 33 | 24 | 20 | 3 | 29 | 26 |
| 20 | 33 | 37 | 23 | 19 | − 5 | 27 | 24 |
| 21 | 35 | 34 | 13 | 17 | − 23 | 23 | 25 |
| 22 | 36 | 38 | 26 | 16 | 12 | 34 | 31 |
| 23 | 34 | 35 | 14 | 18 | − 16 | 39 | 26 |
| 24 | 30 | 37 | 19 | 15 | 9 | 38 | 29 |
| 25 | 29 | 36 | 21 | 14 | 14 | 33 | 32 |
| 26 | 37 | 33 | 15 | 19 | − 24 | 30 | 25 |
| 27 | 43 | 36 | 17 | 18 | Not Applicable | 31 | 27 |
| 28 | 39 | 37 | 12 | 15 | Not Applicable | 37 | 28 |
| 29 | 38 | 34 | 20 | 17 | Not Applicable | 35 | 24 |
| 30 | 32 | 33 | 16 | 14 | Not Applicable | 24 | 23 |
| 31 | 42 | 35 | 22 | 16 | Not Applicable | 36 | 30 |
| 32 | 41 | 38 | 11 | 19 | Not Applicable | 26 | 22 |
| 33 | 36 | 34 | 10 | 20 | Not Applicable | 22 | 22 |
| 34 | 38 | 31 | 25 | 22 | 16 | 11 | 28 |
| 35 | 41 | 39 | 18 | 17 | 1 | 18 | 27 |
| 36 | 33 | 37 | 14 | 14 | 6 | 26 | 25 |
| 37 | 35 | 32 | 19 | 21 | 15 | 28 | 32 |
| 38 | 29 | 38 | 21 | 32 | − 6 | 30 | 30 |
| 39 | 31 | 40 | 17 | 24 | 8 | 22 | 24 |
| 40 | 37 | 36 | 20 | 31 | 4 | 34 | 31 |
| 41 | 30 | 35 | 22 | 28 | − 20 | 25 | 22 |
| 42 | 40 | 30 | 16 | 25 | 13 | 19 | 29 |
| 43 | 42 | 32 | 18 | 29 | − 10 | 16 | 25 |
| 44 | 39 | 30 | 26 | 15 | − 25 | 17 | 27 |
| 45 | 44 | 34 | 15 | 19 | 11 | 29 | 26 |
| 46 | 34 | 31 | 23 | 22 | − 15 | 35 | 32 |
| 47 | 32 | 38 | 11 | 17 | − 7 | 21 | 29 |
| 48 | 43 | 33 | 22 | 19 | 10 | 22 | 30 |
| Average | 36.5 m | 34 | 18.2 | 19.9 | − 2.4 | 25.7 | 24.6 |
Surgical Technique
All procedures were done by different pediatric orthopedic surgeons at our institutions (6 surgeons). The patient is placed in supine position and the iliac crest is approached using the anterior smith peterson approach. Iliac crest apophysis is split longitudinally using scalpel. The inner and outer periosteal layers are elevated off the iliac bone down to greater sciatic notch. Small Homman retractors are placed in the sciatic notch to protect neurovascular structures. Osteotomy done using electrical saw and completed with osteotomes starting from just superior to anterior inferior iliac spine (AIIS) heading to greater sciatic notch. The osteotomy should be complete and assessment done for opening without resistance. Tricortical wedge of bone (bone graft) is cut from the top of the iliac crest with 1 cm base. The distal fragment of osteotomy is grasped with a towel clip, and pulled in anterolateral direction in line with ilium and another towel clip to hold the proximal fragment. The bone graft is inserted into the osteotomy site and two 1.6 mm threaded k wires inserted heading to the triradiate cartilage and reaching just above the acetabulum. Fluoroscopic images taken to confirm acetabular correction and k wires length. Wires are cut leaving 5 mm off the bone to aid in later removal and apophysis is closed with absorbable sutures and subcutaneous layer and skin are closed as usual. The patient is placed in single leg spica with non weight bearing for 6 weeks. First visit after surgery is done at 6 weeks time for cast off and hip x ray and patients are allowed to start weight bearing as tolerated. K wires are removed routinely 6 months postoperatively under general anesthesia Figs. 1, 2.
Fig. 1.
Case 1 with preoperative (A), postoperative (B), and final follow-up (C) anteroposterior pelvic radiographs in a patient who underwent Salter osteotomy for isolated left acetabular dysplasia
Fig. 2.
Case 2 with preoperative (A), postoperative (B), and final follow-up (C) anteroposterior pelvic radiographs in a patient who underwent open reduction, capsulorrhaphy and Salter osteotomy for left DDH
A matched pair t test was used for comparisons of measurements for AI, and CEA in all preoperative, postoperative, and follow-up radiographs. As multiple tests were performed the significance level was adjusted using Bonferroni’s correction. The adjusted critical p value for significance was taken as 0.0125.
Results
A total of 44 patients (48 procedures) who underwent Salter Innominate osteotomy for DDH were reviewed retrospectively. The mean age of patients was 30.2 months. 32 were females and 12 were male patients and the left hip was involved in 28 cases while the right hip was involved in 20 cases. The minimum follow-up was 29 months (mean 36.5 months; range, 29–44 months). The demographic data are listed in Table 1.
Table 1.
Details of patients treated with salter innominate osteotomy with diagnoses, prior treatment, and concomitant procedures
| Case no | Gender | Age at Surgery (months) | Hip (R/L) | Diagnosis | Previous procedure (open/closed reduction) | Additional procedures done with salter innominate osteotomy |
|---|---|---|---|---|---|---|
| 1 | F | 32 | L | Dysplasia | None | None |
| 2 | F | 29 | L* | Dysplasia | None | None |
| 3 | Same patient (#2) | 35 | R* | Dysplasia | None | None |
| 4 | M | 23 | R | Subluxation | CR | None |
| 5 | F | 27 | L | Subluxation | CR | None |
| 6 | M | 21 | R | Subluxation | CR | None |
| 7 | M | 26 | R | Dislocation | CR | None |
| 8 | F | 35 | L | Dislocation | CR | None |
| 9 | F | 31 | L | Dislocation | None | OR |
| 10 | M | 36 | R | Dislocation | CR | None |
| 11 | M | 18 | R | Dislocation | None | OR |
| 12 | F | 41 | L | Dislocation | None | OR |
| 13 | F | 24 | R | Dislocation | OR | None |
| 14 | F | 34 | L | Dysplasia | None | None |
| 15 | F | 40 | L | Dysplasia | None | None |
| 16 | F | 28 | R | Subluxation | CR | None |
| 17 | F | 38 | L | Subluxation | None | OR |
| 18 | M | 19 | R | Subluxation | OR | None |
| 19 | F | 22 | L | Subluxation | CR | None |
| 20 | F | 25 | R | Subluxation | CR | None |
| 21 | F | 37 | L | Subluxation | None | OR |
| 22 | F | 20 | L* | Dysplasia | None | None |
| 23 | Same patient (#22) | 27 | R* | Dysplasia | None | None |
| 24 | F | 30 | R | Subluxation | CR | None |
| 25 | F | 41 | L | Subluxation | CR | None |
| 26 | M | 20 | R | Subluxation | CR | None |
| 27 | M | 21 | R | Dislocation | CR | None |
| 28 | F | 24 | L | Dislocation | CR | None |
| 29 | F | 33 | L | Dislocation | None | OR |
| 30 | M | 39 | R | Dislocation | CR | None |
| 31 | F | 25 | R | Dislocation | None | OR |
| 32 | F | 36 | L | Dislocation | None | OR |
| 33 | F | 32 | R | Dislocation | None | OR |
| 34 | F | 34 | L | Dysplasia | None | None |
| 35 | F | 30 | L | Dysplasia | CR | None |
| 36 | F | 28 | R | Subluxation | CR | None |
| 37 | F | 38 | L | Subluxation | CR | None |
| 38 | M | 40 | L | Subluxation | OR | None |
| 39 | F | 31 | L | Subluxation | CR | None |
| 40 | F | 23 | L | Subluxation | CR | None |
| 41 | F | 37 | L | Subluxation | None | OR |
| 42 | F | 29 | L | Dysplasia | None | None |
| 43 | F* | 32 | L* | Dysplasia | None | None |
| 44 | Same patient (#43) | 40 | R* | Dysplasia | None | None |
| 45 | M | 33 | L* | Dysplasia | None | None |
| 46 | M | 31 | R* | Dysplasia | None | None |
| 47 | F | 23 | L | Subluxation | CR | None |
| 48 | F | 23 | L | Subluxation | CR | None |
| Total | 44 pateints (32 F, 12 M) | Average 30 months | 28 L, 20 R | Dysplasia 14, subluxation 20, dislocation 14 | None 23, CR 22, OR 3 | None 38, OR 10 |
*Same patient. F Female; M male L left; R right; CR closed reduction; OR open reduction
Table 2 describes the resulting outcomes in our series. The mean follow-up period was 36.5 months (range 29–44 months). Femoral head coverage as evaluated by AI and CEA improved in all patients after Salter innominate osteotomy in our series. The AI averaged 34.29° (SD 2.9°), 18.2° (SD 4.7°) and 19.9° (SD 4.7°) on preoperative, postoperative and final follow-up radiographs, respectively. Preoperative versus postoperative AI values revealed a significant difference in mean difference (95% CI 14–22, P < 0.0001) as well as final follow-up versus preoperative values (95% CI 12.6 − 20.6, P < 0.0001); however, Postoperative versus follow-up AI values showed nonsignificant difference (95% CI 0–− 4.3, P = 0.0355).
CEA measurements underwent statistical comparison only on the non dislocated hips (patients with subluxated hip or dysplastic acetabulum) and revealed that preoperative and postoperative CEA values have a significant difference (the mean difference is 27.4°, 95% CI 23.4–41.2; P < 0.0001,). Similarly, there was a significant difference in mean difference between preoperative and follow-up CEA values (the mean difference is 24.6°, 95% CI: 23.25–29.43; P < 0.0001,). However, there was no significant difference between postoperative and follow-up CEA measurements (the mean difference is 7°, 95% CI 3.2–8.5; P < 0.212).
We reviewed the complications related to the technical aspects of salter osteotomy in the treatment group which included difficulty in removing the wires because of bone growth and the wires being buried in the iliac bone in 16 cases (33%). No graft dislodgement or pin migration has been reported.
Discussion
Despite the effective diagnostic and treatment options available today for detecting and treating DDH, we continue to see a high number of children with acetabular dysplasia. Left untreated, acetabular dysplasia can progress to hip arthrosis [2, 8, 9]. The Salter innominate osteotomy has been identified as an effective surgery for treatment of dysplastic hip in children [1, 3–7]. The objective of our study was to assess the results of Salter osteotomy in patients diagnosed with DDH on radiographic parameters including the AI and CEA.
We have found in our study an improvement in AI from 34° preoperatively to 19.9° at final follow, and this is comparable with other published papers in the literature. Carvalho Filho et al. [11] showed an improvement of AI from 39° to 22° at final follow up. Yagmurlu et al. [12] showed an improvement in AI from 37.8° to 21.2, and El-Sayed et al. [10] achieved an improvement from 41.56° preoperatively to 20.41° at final follow up in children younger than four years.
The CEA was improved in all cases in our study from − 2.4° preoperatively to 25.7° on the final follow up radiograph and this was lower than values achieved by by El-Sayed et al. [10] who achieved an improvement in the CEA to 32.3° the final follow up. Carvalho Filho et al. [11] reported an improvement of CEA from 11.1° to 28° at final follow up.
Our study has many limitations. First it is a retrospective study analyzing the radiological results only without clinical consideration. Second, part of improvements in radiological parameters could be the result of natural remodeling of the acetabulum as many of our patients are younger than 3 years. Finally, the procedures have been done by multiple pediatric orthopedic surgeons and mobilizing the osteotomy fragments could vary between them and this will affect the final outcome. However, this variation could represent the real practice in any institution.
Conclusion
In our hands, use of Salter innominate osteotomy for acetabular dysplasia in patients with DDH was associated with good radiological outcomes. The Salter innominate osteotomy was able to improve lateral acetabular coverage of the hip to almost near-normal radiographic values.
Declarations
Conflict of Interest
The authors declare that they have no conflict of interest.
Ethical Approval
This article does not contain any studies with human or animal subjects performed by the any of the authors.
Informed Consent
For this type of study informed consent is not required.
Footnotes
Publisher's Note
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