INTRODUCTION
Developmental dysplasia of the hip (DDH) is a common pediatric hip disorder that involves incomplete acetabulum development leading to a shallow acetabular surface. DDH can lead to hip pain, hip joint instability/dislocation, and/or early development of hip osteoarthritis (Cady, 2006). Previous research reported that the incidence of DDH is higher among Hispanic populations and lower among Black populations (Loder and Shafer, 2015). The annual prevalence of DDH across populations is expected to be 1.7 per 1000 infants (births-12 months) (Degnan et al., 2021). In Saudi Arabia, DDH has high incidence and prevalence rates that are estimated at 3.1-4.9 per 1000 births and 6-8%, respectively (Alrashdi et al., 2024). Common risk factors for DDH include female sex, marriage with close relatives (Guner et al., 2013), breech birth presentation, and/or a family history of DDH (de Hundt et al., 2012; Harsanyi et al., 2020). Globally, several health-related programs have been initiated that aim to screen and manage children with DDH at an early stage with an overall goal of reducing potential future disabilities associated with DDH as well as improving the quality of life in this patient population (Rhodes and Aarvold, 2022).
Specifically, in the United Kingdom, a national DDH screening program was initiated in 1986, called the Newborn and Infant Physical Examination (NIPE) (Rhodes and Aarvold, 2022). The NIPE’s goal was to identify children born with various congenital abnormalities, including developmental hip disorders, during the first 72 h of life and refer children at high risk for further evaluation and tailored medical interventions, as needed, to reduce potential future morbidity and/or mortality risks (Rhodes and Aarvold, 2022). Similarly, in Saudi Arabia, a national health program—the National Hip Dysplasia Program (NHDP)—that was designed to identify children with DDH was launched in December 2016. This program aims to provide early screening and treatment plans for children with DDH in Saudi Arabia, and, to date, the program has provided medical and/or surgical interventions for many children with DDH. However, the results of this program have not been published or publicly disseminated to compare its performance with other similar programs around the world. In the current study, we used data from the NHDP in Saudi Arabia to characterize DDH cases that were clinically treated in two major Saudi regions. The NHDP’s goals include early detection of DDH, providing standardized treatment protocols, and training healthcare professionals on the state-of-the-art DDH management. In this study, we aim to describe that preliminary outcomes from this clinical program will provide essential information to clinicians working with children with DDH in Saudi Arabia regarding understanding of clinical presentation and interventions used in the treatment of DDH. Additionally, the current study will further inform future clinical studies to identify potential factors associated with better outcomes in this patient population, specifically in Saudi Arabia. Understanding the clinical features, investigation procedures, and interventions in patients with DDH will help bridge the gaps identified in previous studies and highlight the clinical significance of the study for researchers, clinicians, and patients. Such information would guide future clinical studies regarding patient characteristics, recurrence rates, and disease patterns.
MATERIALS AND METHODS
The National Hip Dysplasia Program
The NHDP is a Saudi Arabian outreach program that was launched in December 2016. The overall goal of this unique program is to provide specialized surgical treatments for neglected DDH cases across general hospitals in underserved regions of Saudi Arabia. The Saudi NHDP operates its mission in five different Saudi regions that have less specialized pediatric orthopedic surgeons and high rates of DDH (Alrashdi et al., 2024). The program uses a telemedicine approach to initiate the first contact between the orthopedic surgeon and potential DDH patients/parents as well as their primary physician in collaboration with the hosting hospital (located in one of the five different Saudi regions where the patients/families are living). This preliminary remote evaluation was designed to filter DDH cases for diagnosis/confirmation and schedule candidates for surgery, as appropriate, once the diagnosis was confirmed. Diagnosis of DDH was confirmed using the recommended physical and radiological diagnostic criteria (Bakarman et al., 2023). Following the creation of a list of approximately 10-20 DDH patients that were potentially candidates for surgery, the principal pediatric orthopedic surgeon of the NHDP (TSA) traveled to visit the assigned hospital. During each visit (often 2-3 consecutive days), the principal orthopedic surgeon (TSA) spent the morning times performing DDH surgeries for those who had been screened, diagnosed, and deemed surgical candidates previously. Additionally, the afternoons during these visits were used for post-surgery follow-up appointments and the screening/evaluation of new potential DDH cases.
Since the Saudi NHDP started in 2016, a total of 93 surgical visits/missions were completed with more than 1000 surgical procedures being performed (across all regions). These surgical procedures included closed hip reductions, open hip reductions, and/or pelvic osteotomy as well as open hip reduction and pelvic and/or femoral osteotomy. In addition to providing surgical treatments, the Saudi NHDP also provides training to pediatric orthopedic fellows on the clinical evaluation and surgical treatment of DDH to increase the available workforce required to more effectively treat DDH in Saudi Arabia.
Participants
In the current study, we included patients who received treatments provided by the Saudi NHDP. Our inclusion criteria included children with a confirmed diagnosis of DDH (diagnosis was confirmed by TSA, using clinical and radiograph measures described above) who received interventions from this program, regardless of sex or whether interventions were conservative, medical, or surgical. We excluded patients with pediatric disorders or conditions other than DDH such as avascular necrosis, neuromuscular diseases, and/or myelomeningocele.
Variables and data reported in the current study
We formally requested access to data collected as a part of the Saudi NHDP and obtained access to all variables reported in the current study. All data obtained were de-identified and were from two major Saudi regions, the Northern Borders region and the Al-Jouf region, where higher incidence and prevalence of DDH was expected (Alrashdi et al., 2024). Because this study was retrospective, patient consent was not required. The ethical approval for conducting this study was obtained from the institutional review board at Majmaah University (IRB no.: H-01-R-088), in accordance with the Declaration of Helsinki. We included data from April 2017 to February 2021 (46-month duration, currently available data). Our variables of interest included age at first surgery, sex, involved side, diagnosis, Tonnis grade (for DDH severity) (Stoker, 1988), treatments provided (conservative or surgical interventions), and recurrence rates for failed surgeries.
The study design was a retrospective cohort study conducted in two regions of Saudi Arabia (Northern Borders and Al-Jouf). Patients were identified and referred to the NHDP through primary care physicians and local hospitals in the respective regions. Exclusion criteria included patients with other pediatric disorders or conditions that could affect hip development. The data were de-identified, and patients’ identifiable information was replaced with codes to ensure patient confidentiality and privacy. In addition, access to data was restricted to the authorized personnel only. We processed and cleaned all relevant data using Microsoft Excel, and descriptive statistics including measures of central tendency and dispersion (means and standard deviations) as well as frequencies and percentages were computed using IBM SPSS Statistics (v. 29.0; Chicago, IL, USA). Independent t-tests were used to compare age differences between Northern Borders region and Al-Jouf region, whereas chi-square tests were used to determine the differences between Northern Borders region and Al-Jouf region concerning sex and the involved side of DDH.
RESULTS
The Saudi NHDP
The Saudi NHDP has helped in reducing the waiting time for receiving surgical treatment for children with DDH in a tertiary hospital (waiting time has been reduced to 1-6 weeks compared to 6-9 months before starting the NHDP). Additionally, the NHDP has reduced treatment cost because operations were done at patients’ living locations/cities, which saves costs associated with referrals to a tertiary medical center (approximately saving 50,000-65,000 SR, equivalent to $13,000-$17,000).
Demographic characteristics of the cohort
Out of 404 potential children with DDH, a total of 300 children were included in this study (Northern Borders region, n = 184 children; Al-Jouf region, n = 116 children). In both regions, all children were evaluated and treated by the same pediatric orthopedic consultant surgeon (TSA), who specializes in hip surgery with 20 years of clinical experience. On average, children were first seen at the age of 20.0 ± 13.0 months in the Northern Borders region and at an age of 22.0 ± 12.0 months in Al-Jouf region (Table 1). The majority of children treated through the program were females (Northern Borders region = 83.2%; Al-Jouf region = 81.0%; Table 1). Regarding the involved side of DDH, most of the cases were bilateral (62.6% in both regions), followed by the left side (19.7% in both regions) and then the right side (17.7% in both regions) (Table 1). Although there were more bilateral DDH cases than unilateral cases (Table 1), there was a significantly greater proportion of bilateral DDH cases in the Northern Borders region (n = 129; 70.1%) compared to the Al-Jouf region (n = 59; 51.0%) (P = 0.003). There were no significant differences in the age of included patients or sex distribution between the two regions (all P > 0.05). Table 1 provides detailed characteristics of the included patients.
Descriptive statistics and regional comparisons of the included patients from the National Hip Dysplasia Program.
| Northern Borders region (n = 184) | Al-Jouf region (n = 116) | t or χ 2 | P (level of significance) | Total sample combined (n = 300) | |
|---|---|---|---|---|---|
| Age (months; M ± SD) | 20.0 ± 13.0 | 22.0 ± 12.0 | −0.885 | 0.635 | 21.0 ± 12.5 |
| Sex, n (%) | |||||
| Males | 31 (16.8) | 22 (19.0) | 0.219 | 0.640 | 53 (17.7) |
| Females | 153 (83.2) | 94 (81.0) | 247 (82.3) | ||
| Involved side, n (%) | |||||
| Right | 27 (14.7) | 26 (22.0) | 11.4 | 0.003 | 53 (17.7) |
| Left | 28 (15.2) | 31 (27.0) | 59 (19.7) | ||
| Bilateral | 129 (70.1) | 59 (51.0) | 188 (62.6) | ||
Abbreviations: M, means; SD, standard deviation; t, t-test.
Clinical characteristics of children with unilateral DDH (n = 112)
In the Northern Borders region, most of the children with right-sided DDH had Tonnis grades II-IV (Table 2), whereas the majority of those with left-sided DDH had a Tonnis grade of II (50.0%; Table 2). In addition, the majority of children with unilateral DDH were treated by open reduction surgical treatment (Table 2), with recurrence rates of 14.8% for right-sided DDH and 7.1% for left-sided DDH (Table 2).
Clinical characteristics of patients with DDH treated in the Northern Borders region.
| Variable | Unilateral DDH (n = 55) | Bilateral DDH (n = 129 hips) | ||
|---|---|---|---|---|
| Right (n = 27) | Left (n = 28) | Right | Left | |
| Age at first surgery (months; M ± SD) | 21.7 ± 13.8 | 21.6 ± 16.3 | 19.5 ± 11.4 | — |
| Age at second surgery (months; M ± SD) | — | — | — | 20.4 ± 14.3 |
| Tonnis grade, n (%) | ||||
| Grade I | 1 (4.2) | 2 (7.7) | 30 (25.6) | 19 (21.8) |
| Grade II | 8 (33.3) | 13 (50.0) | 26 (22.2) | 22 (25.3) |
| Grade III | 6 (25.0) | 5 (19.2) | 24 (20.5) | 19 (21.8) |
| Grade IV | 9 (37.5) | 6 (23.1) | 37 (31.6) | 27 (31.0) |
| Procedure, n (%) | ||||
| CR | 5 (18.5) | 7 (25.0) | 29 (24.2) | 29 (29.9) |
| OR | 11 (40.7) | 17 (60.7) | 46 (38.3) | 14 (14.4) |
| FS/graft | 8 (29.6) | 2 (7.1) | 42 (35.0) | 50 (51.5) |
| Others | 3 (11.1) | 2 (7.1) | 3 (2.5) | 4 (4.1) |
| Recurrence, n (%) | ||||
| Yes | 4 (14.8) | 2 (7.1) | 12 (9.3) | |
| No | 23 (85.2) | 26 (92.6) | 117 (90.7) | |
| Both sides operated, n (%) | ||||
| Yes | — | — | 80 (62.0) | |
| No | — | — | 49 (38.0) | |
| Time between surgeries (days; M ± SD) | N/A | N/A | 139.6 ± 191.3 | |
Abbreviations: CR, closed reduction; DDH, developmental dysplasia of the hip; FS, femoral shortening; M, mean; N/A, not applicable; OR, open reduction; SD, standard deviation.
In the Al-Jouf region, the majority of children with right-sided DDH had a Tonnis grade of IV (48.0%; Table 3), whereas children with left-sided DDH had approximately equal proportions of Tonnis grades of II-IV (all 31.0%; Table 3). The majority of children with unilateral DDH were treated by femoral shortening with graft (right-sided DDH = 69.2%; left-sided DDH = 54.9%; Table 3), with a recurrence rate of 7.7% for right-sided DDH only (Table 3).
Clinical characteristics of patients with DDH treated in the Al-Jouf region.
| Variable | Unilateral (n = 57) | Bilateral (n = 59 hips) | ||
|---|---|---|---|---|
| Right (n = 26) | Left (n = 31) | Right | Left | |
| Age at first surgery (months; M ± SD) | 23.3 ± 13.2 | 21.8 ± 9.5 | 20.8 ± 12.2 | — |
| Age at second surgery (months; M ± SD) | — | — | — | 31.4 ± 12.7 |
| Tonnis grade, n (%) | ||||
| Grade I | 2 (8.0) | 2 (6.9) | 17 (29.8) | 6 (16.7) |
| Grade II | 6 (24.0) | 9 (31.0) | 6 (10.5) | 10 (27.8) |
| Grade III | 5 (20.0) | 9 (31.0) | 13 (22.8) | 4 (11.1) |
| Grade IV | 12 (48.0) | 9 (31.0) | 21 (36.8) | 16 (44.4) |
| Procedure, n (%) | ||||
| CR | 2 (7.7) | 5 (16.1) | 14 (23.7) | 0 (0.0) |
| OR | 5 (19.2) | 9 (29.0) | 17 (28.8) | 4 (16.7) |
| FS/graft | 18 (69.2) | 17 (54.9) | 27 (45.8) | 20 (83.3) |
| Others | 1 (3.8) | 0 (0.0) | 1 (1.7) | 0 (0.0) |
| Recurrence incidence, n (%) | ||||
| Yes | 2 (7.7) | 0 (0.0) | 3 (5.2) | |
| No | 24 (92.3) | 31 (100) | 55 (94.8) | |
| Both sides operated, n (%) | ||||
| Yes | — | — | 33 (57.9) | |
| No | — | — | 24 (42.1) | |
| Time between surgeries (days; M ± SD) | N/A | N/A | 242.1 ± 132.2 | |
Abbreviations: CR, closed reduction; DDH, developmental dysplasia of the hip; FS, femoral shortening; M, mean; N/A, not applicable; OR, open reduction; SD, standard deviation.
Clinical characteristics of children with bilateral DDH (n = 188)
In the Northern Borders region, children with bilateral DDH had similar proportions of Tonnis grades of I-IV (Table 2), whereas in the Al-Jouf region, the majority of children with bilateral DDH had Tonnis grades of IV (40.6%; Table 3). In the Northern Borders region, treatment of bilateral DDH cases included open reduction surgery (26.35%) and femoral shortening osteotomy with graft (43.25%), with a recurrence rate of 9.3% (Table 2). In the Al-Jouf region, treatment of bilateral DDH cases included femoral shortening with graft (64.5%), with a recurrence rate of 52% (Table 3). Overall, more than half of the children with bilateral DDH cases underwent operations for both sides (Northern Borders region = 62.0%; Al-Jouf region = 57.9%). Finally, the average time between the first and the second surgeries was 139.6 ± 191.3 months in the Northern Borders region and 242.1 ± 132.2 months in the Al-Jouf region.
DISCUSSION
The findings from the current study demonstrated that a large volume of children with DDH were diagnosed and treated through the Saudi NHDP in the Northern Borders and Al-Jouf regions of Saudi Arabia between 2017 and 2021. In both regions, most of the included children with DDH treated in the NHDP were females and had bilateral DDH. Overall and on average, children with DDH were first seen at approximately 18 months or older, indicating relatively late detection of DDH in Saudi Arabia (it is recommended to screen/diagnose DDH from birth through 6 months of age) (Agostiniani et al., 2020; Bakarman et al., 2023). Late detection of DDH could be reduced if a national screening program were implemented (Schwend et al., 2014; Cheok et al., 2023). The findings from the current study also indicated that children with DDH commonly present with a range of Tonnis grades and undergo an open reduction surgery with or without femoral shortening osteotomy with relatively acceptable recurrence rates (5.2-14.9%). Overall, this study provides important clinical insights into understanding the role of the NHDP in enabling DDH diagnosis and treatment as well as the current approaches used in treating children with DDH in two major regions of Saudi Arabia.
The results in the current study are in line with other previously published studies that found that a higher proportion of females are diagnosed with DDH when compared to males (Tao et al., 2023). In our study, the male:female ratio was 1:5 in the Northern Borders region and 1:4 in the Al-Jouf region. A recent meta-analysis reported that females have approximately a 46% greater risk of developing and being diagnosed with DDH than males (odds ratio: 1.46), when including a total of 28 studies and pooling from several countries, including China, the United States, Australia, England, Iran, and Turkey (Tao et al., 2023). In addition, several previously published studies reported that female sex is a known and well-established risk factor for DDH development in Saudi Arabia (Zamzam et al., 2009; Alsiddiky et al., 2012; Ibrahim et al., 2021), as well as in other countries (de Hundt et al., 2012; Blankespoor et al., 2020). Our findings from the NHDP support previous findings that female sex is a key risk factor for DDH development and diagnosis in Saudi Arabia. Clinicians working with children should implement early DDH screening and treatment programs for newborns, specifically for females.
Regarding laterality, unlike other previous studies that found that DDH affects the left side in greater proportions (unilaterality) (Loder and Skopelja, 2011; Sankar et al., 2011), our findings from the current study indicated that there were higher proportions of children with bilateral DDH when compared to children with unilateral DDH in both Saudi regions (51-70%). Previous work suggests that diagnosing DDH at an older age may increase the likelihood of bilateral DDH when compared to diagnosis at earlier ages (Loder and Skopelja, 2011). The increased bilateral representation in our cohort may have also been due to breech position during pregnancy, which commonly associates with bilateral DDH development (Lambeek et al., 2013). Given that bilateral involvement of DDH may indicate dislocation after initial treatment (Lambeek et al., 2013), understanding the causal relationship between risk factors and bilaterality of DDH in Saudi Arabia requires further future research.
Tonnis grade evaluates DDH severity and the success of conservative treatment, with advanced Tonnis grades indicating the need for further advanced surgical intervention (Yilar and Topal, 2023). Our findings from the current study indicated that most of the treated children had a Tonnis grade of IV, indicating greater DDH severity. This is consistent with the proportion of surgical interventions documented in this study (>50% of all cases). This is not surprising, as children with DDH in this study were referred to the pediatric orthopedic surgery clinic as a part of the NHDP with relatively late DDH diagnoses. In addition, milder DDH severity (Tonnis grades of I and II) might have been more regularly misdiagnosed or not recognized due to the lack of early screening programs in Saudi Arabia. A previous study found high rates of missed DDH, with more than 25% due to a lack of early ultrasound screening (Fan et al., 2023). The findings in our study may suggest the need for policymakers to necessitate early screening programs to avoid late or misdiagnosed DDH, which could negatively affect the success of conservative treatments and overall long-term hip joint health in this patient population.
In both regions (Northern Borders and Al-Jouf), children with DDH received various surgical treatments, mainly due to a failure of previous conservative treatments, severe/higher Tonnis grades, and/or late DDH detection. This is concerning because surgical treatment is often invasive and potentially could be avoided if early screening and casting/bracing programs were implemented (Price and Ramo, 2012; Suqaty et al., 2023). In the current study, conservative treatment (closed reduction) was implemented for only approximately 25% of the DDH cases in the Northern Borders region and only 12% in Al-Jouf region. Perhaps, time between the two surgeries for those with bilateral DDH has affected these findings. In the Al-Jouf region, children with DDH waited approximately 240 days before receiving corrective surgery for the second hip compared to 140 days in the Northern Borders region. Thus, children with bilateral DDH should seek interventions for the second hip at the earliest possible time to avoid the surgical option in the near future. Clinicians who work with the pediatric population may educate families of children with bilateral DDH on how to optimize hip growth of the other hip upon treating the first hip for the first time.
Surgical interventions for DDH are also often costly. Based on our clinical experience and our knowledge regarding the health system in Saudi Arabia, surgical treatment of DDH would cost children and families approximately in the range of 50,000-60,000 SR ($13,000-$17,000) per one hip. In the current study, we expected that the average cost of one surgical intervention for children with DDH was approximately 60,000 SR (equivalent to $16,000). This is lower than the typical cost of hip arthroplasty and/or osteotomy surgeries ($11,582 per surgery). However, the relatively low cost of surgery in Saudi Arabia (compared to other countries) may be due to the governed healthcare system which reduces extra payment for professionals and only counts in-hospital and hospital services costs. Surgical treatment given for children with DDH included in the current study has a minimal re-dislocation rate (overall <10%). Perhaps, standardization of the treatment protocol and/or the experience of the treating pediatric surgeon played an important role in maintaining the success of the provided treatment. Reasons for recurrence of surgical intervention in the current study included failed closed reduction, cast avascular necrosis, and/or re-dislocation after open reduction with femoral shortening osteotomy.
LIMITATIONS
The current study has several limitations that need to be considered when interpreting its findings. Firstly, this study used a retrospective design. This nature of the study design lacks several important variables, such as if the baby was born in a breech position, anthropometric measures, and functional performance upon screening. However, there were enough key variables to provide preliminary data to characterize the NHDP in Saudi Arabia, as a first step toward facilitating important policy improvements related to DDH screening and early intervention. Additionally, the current study design does not allow for the evaluation of the causal relationship between risk factors and DDH development. However, it was an important first step to identify current practice in a national DDH treatment program to better understand ways to improve it. Lastly, the findings from the current study may not be generalizable to other children with DDH in other parts of the world due to the natural variability in demographics, risk factors, and screening and treatment protocols.
Clinical implications and future directions
This study has several important clinical and policy-related implications. Firstly, we demonstrated that children with DDH are referred to pediatricians or orthopedic clinics through the NHDP at relatively late ages, which could contribute to bilaterality of DDH and/or increased risk of hip re-dislocation after initial conservative treatments (Azzopardi et al., 2011; Loder and Skopelja, 2011). This is important for informing policymakers regarding the importance of initiating early screening and prevention programs for DDH in Saudi Arabia. Secondly, the majority of children included in the current study had bilateral DDH, of which breech birth position could be another contributing (Loder and Skopelja, 2011) clinical risk factor. Early screening programs to evaluate the infant’s position in the womb may allow clinicians to better provide early assessment (and interventions, as needed) of the hip joint to facilitate optimal hip bone growth and avoid other sequelae. Lastly, whereas our current dataset does not include longitudinal outcome-related data, it is critical to monitor the morphological development and/or symptoms of children with DDH to provide additional interventions (conservative or surgical) as necessary to optimize function and long-term joint health. Furthermore, future research should focus on longitudinal monitoring of children with DDH to assess the long-term outcomes of surgical and conservative treatments. Additionally, investigating the effectiveness of early screening programs and their impact on reducing the need for surgical interventions would be valuable. Further studies could also explore the genetic and environmental risk factors associated with DDH to develop targeted prevention strategies.
CONCLUSION
Our study showed that, through the NHDP, children with DDH in Saudi Arabia are referred to the consulting pediatric orthopedic surgeons at relatively older ages, which could result in less than optimal early intervention outcomes and long-term joint health. These findings call for immediate consideration of the implementation of early, nationwide DDH screening protocols/programs with an overall goal of preventing and minimizing the risk and severity of DDH in Saudi Arabia. Currently, due to delayed diagnosis, most children with DDH who seek treatment have a lower likelihood to benefit from conservative treatment, thereby requiring surgical interventions. Finally, delayed DDH diagnosis may further pose an increased economic burden on the healthcare system in Saudi Arabia that could be mitigated with comprehensive screening programs.