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Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling
Journal of Clinical Orthopaedics and Trauma xxx (xxxx) xxx
Contents lists available at ScienceDirect
Journal of Clinical Orthopaedics and Trauma journal homepage: www.elsevier.com/locate/jcot
Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling Oussama Abousamra a, David Deliberato b, Satbir Singh a, Kevin E. Klingele a, c, * a
Department of Orthopedic Surgery, Nationwide Children's Hospital, Columbus, OH, USA Department of Orthopedic Surgery, Doctor's Hospital, Columbus, OH, USA c Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 28 November 2018 Received in revised form 10 September 2019 Accepted 11 September 2019 Available online xxx
Background: This study aims to assess acetabular remodeling following closed vs, open hip reduction in children younger than 2 years of age. Methods: Records of children with DDH, who underwent closed or open reduction, were reviewed. Acetabular index (AI) was measured on radiographs taken prior to reduction and on outcome radiographs taken at age 4 years. Radiographic outcomes were analyzed and residual dysplasia (outcome AI 30) degrees recorded. Results: 42 hips had closed reduction; and 26 hips had open reduction. A higher percentage of hips treated with successful closed reduction, had outcome AI 30 (29% vs. 19% p ¼ 0.387). Residual dysplasia was more common in IHDI-IV hips than IHDI-III hips for both groups. A higher incidence of AVN was seen in the open reduction group (13% vs. 7%; p ¼ 0.43). Conclusion: In children with DDH under the age of two, open reduction with capsulorrhaphy may benefit acetabular remodeling more so than closed reduction despite maintenance of reduction. Although AVN remains a risk, higher remodeling might be expected with open reduction. © 2019 Delhi Orthopedic Association. All rights reserved.
Keywords: DDH Dysplasia Remodeling Osteotomy Open reduction Closed reduction
1. Introduction Acetabular remodeling following hip reduction in developmental dysplasia of the hip (DDH) has been a research interest for the last few decades, and multiple efforts have been made trying to predict the remodeling potential and residual dysplasia with the need for later osteotomy.1e5 Age has been studied as a factor predicting acetabular remodeling and less focus has been directed at the type of reduction. Younger age at reduction and hip joint congruency after the reduction have been reportedly associated with higher remodeling ability2,3,5 Although residual dysplasia was more frequently found when reduction was performed at an older age, whether the reduction was closed or open 3, more concentric position with better congruency was more likely to be obtained with open reduction. Residual acetabular dysplasia and avascular necrosis have been well-reported outcomes after treatment of DDH.1e4,6,7 Open
* Corresponding author. Department of Orthopedics, Nationwide Children's Hospital, 700 Children's Drive Suite A2630, Columbus, OH, 43205-2696, USA. E-mail address: [email protected] (K.E. Klingele).
reduction has been considered a risk factor for AVN.6,7 This study aims to evaluate the effect of the reduction type, closed or open, on acetabular remodeling and residual dysplasia. Complications including AVN following each type of reduction are reported as well.
2. Methods After obtaining the approval of our Institutional Review Board, records of all children who had management for hip dysplasia between 2000 and 2015 were reviewed. Children whose hip dysplasia was associated with an underlying neuromuscular or syndromic diagnosis were excluded. Data of children with idiopathic DDH who underwent closed reduction or open reduction were recorded. All children had their treatment at a single pediatric institution. Hips that underwent open reduction with simultaneous pelvic osteotomy were excluded. Only hips that remained located with an intact Shenton's line throughout the study period were included in the final analysis (one hip was excluded due to re-dislocation). A minimum of 2-year follow up was required for included patients. Demographic data were recorded. Radiographic measurements
https://doi.org/10.1016/j.jcot.2019.09.010 0976-5662/© 2019 Delhi Orthopedic Association. All rights reserved.
Please cite this article as: Abousamra O et al., Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling, Journal of Clinical Orthopaedics and Trauma, https://doi.org/10.1016/j.jcot.2019.09.010
2
O. Abousamra et al. / Journal of Clinical Orthopaedics and Trauma xxx (xxxx) xxx
Table 1 Demographic data of two groups of children with developmental dysplasia of the hip (DDH). SD: standard deviation; mos: months; yrs: years. Total 68 Hips
Males Females Left Hip Right Hip
Age at Reduction (mos) Age at Outcome Radiograph (yrs)
Closed Reduction (42 Hips)
Open Reduction (26 Hips)
Number (%)
Number (%)
4 (10%) 38 (90%) 25 (60%) 17 (40%)
6 (23%) 20 (77%) 16 (62%) 10 (38%)
Mean (SD)
Mean (SD)
P Values
10 ± 5 4.1 ± 1.2
10 ± 5 4 ± 1.2
0.508 0.744
were performed on pre-reduction radiographs and radiographs taken at 4 years of age (outcome radiograph). For hips that had osteotomy prior to age 4 years, the outcome radiograph was considered the one prior to the osteotomy. Age of 4 years was selected as an outcome time point since acetabular remodeling potential starts to diminish afterwards.8 All children underwent a similar post-reduction management with spica casting for a total of 12 weeks (with spica change at 6 weeks post reduction) and 1e2 months of abduction bracing after cast removal. Indications for open reduction included inability to achieve stability with closed reduction or a prior failed closed reduction. All open reductions were performed via an anterior hip approach with concomitant capsulorrhaphy. On the pre-reduction radiograph, all hips were graded according to the International Hip Dysplasia Institute (IHDI) classification,5 and acetabular index (AI)9 was measured. On the outcome radiograph, AI and the modified center edge angle as described by Visser10,11 were measured. AVN was graded on the outcome radiographs according to Bucholz and Ogden classification.12 Two groups of children were identified and compared: children who underwent closed reduction and children who underwent open reduction. AI measurements within each group between the prereduction and outcome radiographs were compared. Residual dysplasia was defined as AI 30 on the outcome radiograph. All data were compared between the two groups at pre-reduction and outcome data points. Statistical analysis was performed using paired t-test for comparisons within the same group, independent t-test for comparisons between the two groups, and chi-square test for comparisons of categorical data. 3. Results A total of 97 hips with DDH had a closed or open reduction at our institution between 2000 and 2014. Eighty two hips (75 patients, 7 had bilateral involvement) had a minimum of 2-year follow up. Fourteen hips had concomitant pelvic osteotomy at the time of open reduction and were excluded. The final analysis included 68 hips (42 hips in the closed reduction group, and 26 in the open reduction group). Pavlik harness had been tried for 36 patients (43 hips: 21 in the closed reduction group and 22 in the
P Values
0.125 0.869
open reduction group). The remaining 39 patients presented to our clinic late with no history of prior treatment. Age and gender distributions were similar in both groups (Table 1). A significantly lower percentage of hips with IHDI-IV were found in the closed reduction group (43% of the hips in the closed reduction group vs. 69% in the open reduction group; p ¼ 0.025). There was no difference between the two groups in prereduction AI (Table 2). AI reduced significantly in both groups between the pre-reduction and the outcome measurements (p < 0.0001). In the closed reduction group, AI reduced by an average 31%, and in the open reduction group, an average 39%. However, this difference was not statistically significant (Table 2; Figs. 1 and 2). The outcome AI and CEA measurements did not show a significant difference between the groups (Table 2). At the age of 4 years, residual dysplasia (outcome AI 30 ) was noted for 5 hips (19%) that underwent open reduction compared to 12 hips (29%) in the closed reduction group (Table 3). Pelvic osteotomy to improve femoral head coverage was offered to all these patients; however, some families elected not to proceed with treatment (Table 3). Avascular necrosis grade III and IV was more common in the open reduction group with 6 hips (23%) affected (3 IHDI-III hips and 3 IHDI-IV hips) compared to 3 hips (7%) in the closed reduction group (2 IHDI-III hips and 1 IHDI-IV hip. However, when looking at hips that had open reduction without a prior failed closed reduction, only 3 hips (3/23 ¼ 13%) had AVN. This difference did not show statistical significance (Table 3). No additional postoperative complications were noted in either group. In those hips with successful closed reduction, an outcome AI> 30 was more commonly seen in the IHDI-IV classified hips than IHDI-III hips (44% vs 17%, p ¼ 0.048). In the open reduction group, only one IHDI-III hip had AI outcome 30 (13%), and 4 IHDI-IV hips (22%) had AI outcome 30. Successful closed reduction of IHDI-IV hips showed a two-fold risk of residual dysplasia compared to open reduction of similarly classified hips (Table 4). 4. Discussion Age at reduction is considered a factor in predicting acetabular development.4,13 However, results are variable and whether younger age at reduction is associated with satisfactory outcome is
Table 2 Radiographic measurements for two groups of children with developmental dysplasia of the hip (DDH). SD: standard deviation; AI: acetabular index; CEA: center edge angle. Total 68 Hips
Pre-reduction AI Outcome AI AI Change AI Percentage Change Outcome CEA
Closed Reduction (42 Hips)
Open Reduction (26 Hips)
Mean (SD)
Mean (SD)
36 ± 5 25 ± 7 11 ± 7 31% ± 19 11 ± 9
36 ± 3 22 ± 6 14 ± 5 39% ± 14 13 ± 7
P Values
0.849 0.119 0.080 0.068 0.208
Please cite this article as: Abousamra O et al., Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling, Journal of Clinical Orthopaedics and Trauma, https://doi.org/10.1016/j.jcot.2019.09.010
O. Abousamra et al. / Journal of Clinical Orthopaedics and Trauma xxx (xxxx) xxx
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Fig. 1. A: Anteroposterior pelvis radiograph of a 10-month-old girl with left developmental dysplasia of the hip. B: Closed reduction was performed and residual dysplasia of the left hip was still noted at the age of 3.8 years. C: Seven months following left pelvic osteotomy.
Fig. 2. A: Anteroposterior pelvis radiograph of an 8-month-old girl with bilateral developmental dysplasia of the hip. B: A staged open reduction of both hips was performed and no residual dysplasia was seen at 4.1 years of age. C: Further acetabular remodeling was seen at the age of 7 years.
Table 3 Outcomes and complications of two groups of children with developmental dysplasia of the hip (DDH). AI: acetabular index; AVN: avascular necrosis. Total 68 Hips
Closed Reduction (42 Hips)
Open Reduction (26 Hips)
Number (%)
Number (%)
Subsequent Osteotomy Outcome AI 30 AVN grade III/IV *
11 (26%) 12 (29%) 3 (7%)
3 (12%) 5 (19%) 3 (13%)
P Values
0.146 0.387 0.432
Excluding three hips with AVN that failed closed reduction/spica and underwent staged, open reduction.
Table 4 The number of hips classified as IHDI-III and IHDI-IV according to the International Hip Dysplasia Institute classification that had residual dysplasia. Total 32 Hips
Outcome AI 30 Total Hips
Outcome AI 30
Closed Reduction IHDI-III (24 Hips)
Open Reduction IHDI-III (8 Hips)
Number (%)
Number (%)
4 (17%) Closed Reduction IHDI-IV (18 Hips) Number (%) 8 (44%)
1 (13%) Open Reduction IHDI-IV (18 Hips) Number (%) 4 (22%)
still controversial.4,13,14 Since no difference in age was found in our study groups, and since almost all our patients were younger than 18 months old at the time of reduction, we believe that age did not play an important factor in our comparison and both our groups were age comparable. In our group of patients, open reduction was more often performed for hips with higher IHDI grade. This is an expected result and could be explained by the difficulty to maintain hip reduction in IHDI-IV hips with closed reduction. The outcome age was selected as 4 years because radiographic parameters around this age3e5 years) have been considered predictive of further acetabular remodeling.1,13 Although no significant difference was found in AI and CEA on the outcome radiographs, a larger improvement of AI was found with open reduction (39% vs.
P Values
0.778 P Values
0.157
31%; p ¼ 0.068). More hips in the closed reduction group had outcome AI 30 (Table 3). Our findings were similar to previous reports that show ~30% of closed reduced hips need future osteotomy.1,2 Unsatisfactory outcome following open reduction is previously reported as 36% 4 and 49%,15,16 which is higher than the findings in this study (19% had outcome AI 30). In cases when outcome AI was 30 and no pelvic osteotomy was performed (1 hip in the closed reduction group and 2 hips in the open reduction group; Table 3), the family elected to wait and monitor remodeling. All these hips eventually needed osteotomy at later ages. The higher risk of AVN with open reduction has been previously reported.6,7 Concomitant pelvic osteotomy was associated with a higher risk.7 Our findings also show a higher risk of AVN with open
Please cite this article as: Abousamra O et al., Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling, Journal of Clinical Orthopaedics and Trauma, https://doi.org/10.1016/j.jcot.2019.09.010
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O. Abousamra et al. / Journal of Clinical Orthopaedics and Trauma xxx (xxxx) xxx
reduction (23% with open reduction vs. 7% with closed reduction). The role of previous conservative treatment in increasing the risk of AVN after open reduction is still not clear. A previous study showed no increased risk when a prior closed reduction and re-dislocation occurred.17 In our study, of the six patients who had AVN, three had undergone a failed prior closed reduction (the hip was closed reduced and spica was applied; however, re-dislocation was noted during the first month of follow up and open reduction was performed). Therefore, it was not clear whether AVN was due to open reduction or the failed closed reduction attempt. AVN occurred in 13% of hips that had open reduction without a prior failed closed reduction. In addition, the role of previous Pavlik harness treatment was difficult to assess. In this study, residual dysplasia and the need for subsequent osteotomy were higher in hips with IHDI-IV grade. This finding supports what has been previously reported.5 In the open reduction group, however, less hips with IHDI-IV grades had residual dysplasia (Table 4). Limitations of this study include its retrospective design in addition to the sample size. Follow up was limited to 4 years of age and there could be potential acetabular growth beyond this age. In addition, the incidence of AVN might be higher with longer-term follow up. Radiographic evaluation was the only available assessment tool to monitor acetabular remodeling. Although our protocol is to obtain post-reduction magnetic resonance imaging (MRI) to confirm the hip position, we do not monitor our patients with advanced imaging. Although MRI has been reported in the evaluation of soft tissue remodeling and monitoring the cartilaginous acetabular index,18,19 radiographs are still the most commonly used monitoring tool in DDH. This study provides a new finding that suggests a role for open reduction in improving acetabular remodeling. This role could be related to the possible ability to obtain a more concentric position with open reduction as reported in a previous study 4 and/or increased stability following capsulorrhaphy. However, it has not been possible to measure and quantify the concentricity and congruency of the hip joint following reduction. This study suggests that, in children with DDH younger than 2 years of age, open reduction could be associated with a higher remodeling ability of the acetabulum than closed reduction and could be considered especially for IHDI-IV hips. Acetabular index change was higher with open reduction, and residual dysplasia was less often noted. The ability to achieve a stable reduction remains the essential factor in deciding whether an open reduction needs to be performed. Surgeons will need to include the risk of AVN and the risk of residual dysplasia in their preoperative counseling and decision making process in order to manage families’ expectations and optimize postoperative outcomes.
Conflicts of interest and source of funding The authors received no funding for this study and have no conflicts of interest to disclose.
References 1. Shin CH, Yoo WJ, Park MS, Kim JH, Choi IH, Cho TJ. Acetabular remodeling and role of osteotomy after closed reduction of developmental dysplasia of the hip. J Bone Joint Surg Am. 2016;98:952e957. 2. Kim HT, Kim JI, Yoo CI. Acetabular development after closed reduction of developmental dislocation of the hip. J Pediatr Orthop. 2000;20:701e708. 3. Albinana J, Dolan LA, Spratt KF, Morcuende J, Meyer MD, Weinstein SL. Acetabular dysplasia after treatment for developmental dysplasia of the hip. Implications for secondary procedures. J Bone Joint Surg Br. 2004;86:876e886. 4. Akagi S, Tanabe T, Ogawa R. Acetabular development after open reduction for developmental dislocation of the hip. 15-year follow-up of 22 hips without additional surgery. Acta Orthop Scand. 1998;69:17e20. 5. Ramo BA, De La Rocha A, Sucato DJ, Jo CH. A new radiographic classification system for developmental hip dysplasia is reliable and predictive of successful closed reduction and late pelvic osteotomy. J Pediatr Orthop. 2016;10:10. 6. Firth GB, Robertson AJ, Schepers A, Fatti L. Developmental dysplasia of the hip: open reduction as a risk factor for substantial osteonecrosis. Clin Orthop Relat Res. 2010;468:2485e2494. 7. Pospischill R, Weninger J, Ganger R, Altenhuber J, Grill F. Does open reduction of the developmental dislocated hip increase the risk of osteonecrosis? Clin Orthop Relat Res. 2012;470:250e260. 8. Kasser JR, Bowen JR, MacEwen GD. Varus derotation osteotomy in the treatment of persistent dysplasia in congenital dislocation of the hip. J Bone Joint Surg Am. 1985;67:195e202. 9. Tonnis D. Normal values of the hip joint for the evaluation of X-rays in children and adults. Clin Orthop Relat Res. 1976;119:39e47. 10. Visser JD. Functional treatment of congenital dislocation of the hip. Acta Orthop Scand Suppl. 1984;206, 1-109. 11. Wiberg G. Studies on dysplastic acetabula and congenital subluxation of the hip joint: with special reference to the complication of osteoarthritis. Acta Chir Scand. 1939;83:53e68. 12. Roposch A, Wedge JH, Riedl G. Reliability of Bucholz and Ogden classification for osteonecrosis secondary to developmental dysplasia of the hip. Clin Orthop Relat Res. 2012;470:3499e3505. 13. Chen IH, Kuo KN, Lubicky JP. Prognosticating factors in acetabular development following reduction of developmental dysplasia of the hip. J Pediatr Orthop. 1994;14:3e8. 14. Arslan H, Sucu E, Ozkul E, Gem M, Kisin B. Should routine pelvic osteotomy be added to the treatment of DDH after 18 months? Acta Orthop Belg. 2014;80: 205e210. 15. Kagawa Y, Endo H, Tetsunaga T, Fujii Y, Miyake T, Ozaki T. Acetabular development after open reduction to treat dislocation of the hip after walking age. J Orthop Sci. 2016;21:815e820. 16. Gholve PA, Flynn JM, Garner MR, Millis MB, Kim YJ. Predictors for secondary procedures in walking DDH. J Pediatr Orthop. 2012;32:282e289. 17. Tang HC, Lee WC, Kao HK, Yang WE, Chang CH. Surgical outcomes of developmental dysplasia of the hip with or without prior failed closed reduction. J Pediatr Orthop. 2015;35:703e707. 18. Ray PS, Redden JF, Ward D. Closed reduction of late-presented DDH: MRI view of remodelling. Orthop Proc. 2003;85-B:109. 19. Li LY, Zhang LJ, Li QW, Zhao Q, Jia JY, Huang T. Development of the osseous and cartilaginous acetabular index in normal children and those with developmental dysplasia of the hip: a cross-sectional study using MRI. J Bone Joint Surg Br. 2012;94:1625e1631.
Please cite this article as: Abousamra O et al., Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling, Journal of Clinical Orthopaedics and Trauma, https://doi.org/10.1016/j.jcot.2019.09.010
Contents lists available at ScienceDirect
Journal of Clinical Orthopaedics and Trauma journal homepage: www.elsevier.com/locate/jcot
Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling Oussama Abousamra a, David Deliberato b, Satbir Singh a, Kevin E. Klingele a, c, * a
Department of Orthopedic Surgery, Nationwide Children's Hospital, Columbus, OH, USA Department of Orthopedic Surgery, Doctor's Hospital, Columbus, OH, USA c Department of Orthopaedics, The Ohio State University Wexner Medical Center, Columbus, OH, USA b
a r t i c l e i n f o
a b s t r a c t
Article history: Received 28 November 2018 Received in revised form 10 September 2019 Accepted 11 September 2019 Available online xxx
Background: This study aims to assess acetabular remodeling following closed vs, open hip reduction in children younger than 2 years of age. Methods: Records of children with DDH, who underwent closed or open reduction, were reviewed. Acetabular index (AI) was measured on radiographs taken prior to reduction and on outcome radiographs taken at age 4 years. Radiographic outcomes were analyzed and residual dysplasia (outcome AI 30) degrees recorded. Results: 42 hips had closed reduction; and 26 hips had open reduction. A higher percentage of hips treated with successful closed reduction, had outcome AI 30 (29% vs. 19% p ¼ 0.387). Residual dysplasia was more common in IHDI-IV hips than IHDI-III hips for both groups. A higher incidence of AVN was seen in the open reduction group (13% vs. 7%; p ¼ 0.43). Conclusion: In children with DDH under the age of two, open reduction with capsulorrhaphy may benefit acetabular remodeling more so than closed reduction despite maintenance of reduction. Although AVN remains a risk, higher remodeling might be expected with open reduction. © 2019 Delhi Orthopedic Association. All rights reserved.
Keywords: DDH Dysplasia Remodeling Osteotomy Open reduction Closed reduction
1. Introduction Acetabular remodeling following hip reduction in developmental dysplasia of the hip (DDH) has been a research interest for the last few decades, and multiple efforts have been made trying to predict the remodeling potential and residual dysplasia with the need for later osteotomy.1e5 Age has been studied as a factor predicting acetabular remodeling and less focus has been directed at the type of reduction. Younger age at reduction and hip joint congruency after the reduction have been reportedly associated with higher remodeling ability2,3,5 Although residual dysplasia was more frequently found when reduction was performed at an older age, whether the reduction was closed or open 3, more concentric position with better congruency was more likely to be obtained with open reduction. Residual acetabular dysplasia and avascular necrosis have been well-reported outcomes after treatment of DDH.1e4,6,7 Open
* Corresponding author. Department of Orthopedics, Nationwide Children's Hospital, 700 Children's Drive Suite A2630, Columbus, OH, 43205-2696, USA. E-mail address: [email protected] (K.E. Klingele).
reduction has been considered a risk factor for AVN.6,7 This study aims to evaluate the effect of the reduction type, closed or open, on acetabular remodeling and residual dysplasia. Complications including AVN following each type of reduction are reported as well.
2. Methods After obtaining the approval of our Institutional Review Board, records of all children who had management for hip dysplasia between 2000 and 2015 were reviewed. Children whose hip dysplasia was associated with an underlying neuromuscular or syndromic diagnosis were excluded. Data of children with idiopathic DDH who underwent closed reduction or open reduction were recorded. All children had their treatment at a single pediatric institution. Hips that underwent open reduction with simultaneous pelvic osteotomy were excluded. Only hips that remained located with an intact Shenton's line throughout the study period were included in the final analysis (one hip was excluded due to re-dislocation). A minimum of 2-year follow up was required for included patients. Demographic data were recorded. Radiographic measurements
https://doi.org/10.1016/j.jcot.2019.09.010 0976-5662/© 2019 Delhi Orthopedic Association. All rights reserved.
Please cite this article as: Abousamra O et al., Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling, Journal of Clinical Orthopaedics and Trauma, https://doi.org/10.1016/j.jcot.2019.09.010
2
O. Abousamra et al. / Journal of Clinical Orthopaedics and Trauma xxx (xxxx) xxx
Table 1 Demographic data of two groups of children with developmental dysplasia of the hip (DDH). SD: standard deviation; mos: months; yrs: years. Total 68 Hips
Males Females Left Hip Right Hip
Age at Reduction (mos) Age at Outcome Radiograph (yrs)
Closed Reduction (42 Hips)
Open Reduction (26 Hips)
Number (%)
Number (%)
4 (10%) 38 (90%) 25 (60%) 17 (40%)
6 (23%) 20 (77%) 16 (62%) 10 (38%)
Mean (SD)
Mean (SD)
P Values
10 ± 5 4.1 ± 1.2
10 ± 5 4 ± 1.2
0.508 0.744
were performed on pre-reduction radiographs and radiographs taken at 4 years of age (outcome radiograph). For hips that had osteotomy prior to age 4 years, the outcome radiograph was considered the one prior to the osteotomy. Age of 4 years was selected as an outcome time point since acetabular remodeling potential starts to diminish afterwards.8 All children underwent a similar post-reduction management with spica casting for a total of 12 weeks (with spica change at 6 weeks post reduction) and 1e2 months of abduction bracing after cast removal. Indications for open reduction included inability to achieve stability with closed reduction or a prior failed closed reduction. All open reductions were performed via an anterior hip approach with concomitant capsulorrhaphy. On the pre-reduction radiograph, all hips were graded according to the International Hip Dysplasia Institute (IHDI) classification,5 and acetabular index (AI)9 was measured. On the outcome radiograph, AI and the modified center edge angle as described by Visser10,11 were measured. AVN was graded on the outcome radiographs according to Bucholz and Ogden classification.12 Two groups of children were identified and compared: children who underwent closed reduction and children who underwent open reduction. AI measurements within each group between the prereduction and outcome radiographs were compared. Residual dysplasia was defined as AI 30 on the outcome radiograph. All data were compared between the two groups at pre-reduction and outcome data points. Statistical analysis was performed using paired t-test for comparisons within the same group, independent t-test for comparisons between the two groups, and chi-square test for comparisons of categorical data. 3. Results A total of 97 hips with DDH had a closed or open reduction at our institution between 2000 and 2014. Eighty two hips (75 patients, 7 had bilateral involvement) had a minimum of 2-year follow up. Fourteen hips had concomitant pelvic osteotomy at the time of open reduction and were excluded. The final analysis included 68 hips (42 hips in the closed reduction group, and 26 in the open reduction group). Pavlik harness had been tried for 36 patients (43 hips: 21 in the closed reduction group and 22 in the
P Values
0.125 0.869
open reduction group). The remaining 39 patients presented to our clinic late with no history of prior treatment. Age and gender distributions were similar in both groups (Table 1). A significantly lower percentage of hips with IHDI-IV were found in the closed reduction group (43% of the hips in the closed reduction group vs. 69% in the open reduction group; p ¼ 0.025). There was no difference between the two groups in prereduction AI (Table 2). AI reduced significantly in both groups between the pre-reduction and the outcome measurements (p < 0.0001). In the closed reduction group, AI reduced by an average 31%, and in the open reduction group, an average 39%. However, this difference was not statistically significant (Table 2; Figs. 1 and 2). The outcome AI and CEA measurements did not show a significant difference between the groups (Table 2). At the age of 4 years, residual dysplasia (outcome AI 30 ) was noted for 5 hips (19%) that underwent open reduction compared to 12 hips (29%) in the closed reduction group (Table 3). Pelvic osteotomy to improve femoral head coverage was offered to all these patients; however, some families elected not to proceed with treatment (Table 3). Avascular necrosis grade III and IV was more common in the open reduction group with 6 hips (23%) affected (3 IHDI-III hips and 3 IHDI-IV hips) compared to 3 hips (7%) in the closed reduction group (2 IHDI-III hips and 1 IHDI-IV hip. However, when looking at hips that had open reduction without a prior failed closed reduction, only 3 hips (3/23 ¼ 13%) had AVN. This difference did not show statistical significance (Table 3). No additional postoperative complications were noted in either group. In those hips with successful closed reduction, an outcome AI> 30 was more commonly seen in the IHDI-IV classified hips than IHDI-III hips (44% vs 17%, p ¼ 0.048). In the open reduction group, only one IHDI-III hip had AI outcome 30 (13%), and 4 IHDI-IV hips (22%) had AI outcome 30. Successful closed reduction of IHDI-IV hips showed a two-fold risk of residual dysplasia compared to open reduction of similarly classified hips (Table 4). 4. Discussion Age at reduction is considered a factor in predicting acetabular development.4,13 However, results are variable and whether younger age at reduction is associated with satisfactory outcome is
Table 2 Radiographic measurements for two groups of children with developmental dysplasia of the hip (DDH). SD: standard deviation; AI: acetabular index; CEA: center edge angle. Total 68 Hips
Pre-reduction AI Outcome AI AI Change AI Percentage Change Outcome CEA
Closed Reduction (42 Hips)
Open Reduction (26 Hips)
Mean (SD)
Mean (SD)
36 ± 5 25 ± 7 11 ± 7 31% ± 19 11 ± 9
36 ± 3 22 ± 6 14 ± 5 39% ± 14 13 ± 7
P Values
0.849 0.119 0.080 0.068 0.208
Please cite this article as: Abousamra O et al., Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling, Journal of Clinical Orthopaedics and Trauma, https://doi.org/10.1016/j.jcot.2019.09.010
O. Abousamra et al. / Journal of Clinical Orthopaedics and Trauma xxx (xxxx) xxx
3
Fig. 1. A: Anteroposterior pelvis radiograph of a 10-month-old girl with left developmental dysplasia of the hip. B: Closed reduction was performed and residual dysplasia of the left hip was still noted at the age of 3.8 years. C: Seven months following left pelvic osteotomy.
Fig. 2. A: Anteroposterior pelvis radiograph of an 8-month-old girl with bilateral developmental dysplasia of the hip. B: A staged open reduction of both hips was performed and no residual dysplasia was seen at 4.1 years of age. C: Further acetabular remodeling was seen at the age of 7 years.
Table 3 Outcomes and complications of two groups of children with developmental dysplasia of the hip (DDH). AI: acetabular index; AVN: avascular necrosis. Total 68 Hips
Closed Reduction (42 Hips)
Open Reduction (26 Hips)
Number (%)
Number (%)
Subsequent Osteotomy Outcome AI 30 AVN grade III/IV *
11 (26%) 12 (29%) 3 (7%)
3 (12%) 5 (19%) 3 (13%)
P Values
0.146 0.387 0.432
Excluding three hips with AVN that failed closed reduction/spica and underwent staged, open reduction.
Table 4 The number of hips classified as IHDI-III and IHDI-IV according to the International Hip Dysplasia Institute classification that had residual dysplasia. Total 32 Hips
Outcome AI 30 Total Hips
Outcome AI 30
Closed Reduction IHDI-III (24 Hips)
Open Reduction IHDI-III (8 Hips)
Number (%)
Number (%)
4 (17%) Closed Reduction IHDI-IV (18 Hips) Number (%) 8 (44%)
1 (13%) Open Reduction IHDI-IV (18 Hips) Number (%) 4 (22%)
still controversial.4,13,14 Since no difference in age was found in our study groups, and since almost all our patients were younger than 18 months old at the time of reduction, we believe that age did not play an important factor in our comparison and both our groups were age comparable. In our group of patients, open reduction was more often performed for hips with higher IHDI grade. This is an expected result and could be explained by the difficulty to maintain hip reduction in IHDI-IV hips with closed reduction. The outcome age was selected as 4 years because radiographic parameters around this age3e5 years) have been considered predictive of further acetabular remodeling.1,13 Although no significant difference was found in AI and CEA on the outcome radiographs, a larger improvement of AI was found with open reduction (39% vs.
P Values
0.778 P Values
0.157
31%; p ¼ 0.068). More hips in the closed reduction group had outcome AI 30 (Table 3). Our findings were similar to previous reports that show ~30% of closed reduced hips need future osteotomy.1,2 Unsatisfactory outcome following open reduction is previously reported as 36% 4 and 49%,15,16 which is higher than the findings in this study (19% had outcome AI 30). In cases when outcome AI was 30 and no pelvic osteotomy was performed (1 hip in the closed reduction group and 2 hips in the open reduction group; Table 3), the family elected to wait and monitor remodeling. All these hips eventually needed osteotomy at later ages. The higher risk of AVN with open reduction has been previously reported.6,7 Concomitant pelvic osteotomy was associated with a higher risk.7 Our findings also show a higher risk of AVN with open
Please cite this article as: Abousamra O et al., Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling, Journal of Clinical Orthopaedics and Trauma, https://doi.org/10.1016/j.jcot.2019.09.010
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O. Abousamra et al. / Journal of Clinical Orthopaedics and Trauma xxx (xxxx) xxx
reduction (23% with open reduction vs. 7% with closed reduction). The role of previous conservative treatment in increasing the risk of AVN after open reduction is still not clear. A previous study showed no increased risk when a prior closed reduction and re-dislocation occurred.17 In our study, of the six patients who had AVN, three had undergone a failed prior closed reduction (the hip was closed reduced and spica was applied; however, re-dislocation was noted during the first month of follow up and open reduction was performed). Therefore, it was not clear whether AVN was due to open reduction or the failed closed reduction attempt. AVN occurred in 13% of hips that had open reduction without a prior failed closed reduction. In addition, the role of previous Pavlik harness treatment was difficult to assess. In this study, residual dysplasia and the need for subsequent osteotomy were higher in hips with IHDI-IV grade. This finding supports what has been previously reported.5 In the open reduction group, however, less hips with IHDI-IV grades had residual dysplasia (Table 4). Limitations of this study include its retrospective design in addition to the sample size. Follow up was limited to 4 years of age and there could be potential acetabular growth beyond this age. In addition, the incidence of AVN might be higher with longer-term follow up. Radiographic evaluation was the only available assessment tool to monitor acetabular remodeling. Although our protocol is to obtain post-reduction magnetic resonance imaging (MRI) to confirm the hip position, we do not monitor our patients with advanced imaging. Although MRI has been reported in the evaluation of soft tissue remodeling and monitoring the cartilaginous acetabular index,18,19 radiographs are still the most commonly used monitoring tool in DDH. This study provides a new finding that suggests a role for open reduction in improving acetabular remodeling. This role could be related to the possible ability to obtain a more concentric position with open reduction as reported in a previous study 4 and/or increased stability following capsulorrhaphy. However, it has not been possible to measure and quantify the concentricity and congruency of the hip joint following reduction. This study suggests that, in children with DDH younger than 2 years of age, open reduction could be associated with a higher remodeling ability of the acetabulum than closed reduction and could be considered especially for IHDI-IV hips. Acetabular index change was higher with open reduction, and residual dysplasia was less often noted. The ability to achieve a stable reduction remains the essential factor in deciding whether an open reduction needs to be performed. Surgeons will need to include the risk of AVN and the risk of residual dysplasia in their preoperative counseling and decision making process in order to manage families’ expectations and optimize postoperative outcomes.
Conflicts of interest and source of funding The authors received no funding for this study and have no conflicts of interest to disclose.
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Please cite this article as: Abousamra O et al., Closed vs open reduction in developmental dysplasia of the hip: The short-term effect on acetabular remodeling, Journal of Clinical Orthopaedics and Trauma, https://doi.org/10.1016/j.jcot.2019.09.010