Prevalence of developmental dysplasia of the hip in Al Jouf province, Saudi Arabia

Abstract

BACKGROUND

Hip dysplasia is a widespread and debilitating musculoskeletal disorder that affects children. Its prevalence varies across different nations.

AIM

To evaluate the prevalence of developmental hip dysplasia (DDH) within the pediatric population of Al Jouf province.

METHODS

From January 2018 to December 2023, children with DDH from all cities of Al Jouf were included in this retrospective cross-sectional study. The disease prevalence was calculated for the entire province as well as for individual cities within the territory.

RESULTS

The study included 427 patients with DDH with an overall prevalence of 0.50%, or 5.0 per 1000 live births. At the city level, Sakaka had the highest prevalence at 14.2 per 1000 Live births followed by Qurayyat at 2.2 per 1000 live births. In contrast, cities like Suwayr, Abu Ajram, and Meegowa did not show any incidence of DDH. Significant differences were observed in the sociodemographic characteristics, such as age, sex, and nationality, across the different cities (P < 0.05).

CONCLUSION

The prevalence of DDH in the Al Jouf province is high. The data delivers invaluable insights into the epidemiology of DDH in the Al Jouf locality. The findings highlight the need for targeted screening of DDH across the province.

Key Words: Al Jouf; Developmental dysplasia of the hip; Developmental hip dysplasia; Epidemiology; Prevalence; Saudi Arabia

Core Tip: Our study reveals a notably high and regionally variable prevalence of developmental hip dysplasia (DDH) among children in Al Jouf province in Saudi Arabia. The findings highlight the need for screening strategies, raise awareness in DDH disease.

INTRODUCTION

Developmental dysplasia of the hip (DDH) encompasses a spectrum of abnormalities affecting the hip joint from minor acetabular dysplasia to full dislocation of the femoral head[1,2] The underlying cause of DDH in children with otherwise normal development remains unclear. However, evidence suggests that the condition's manifestation is caused by genetic and environmental factors, the most commonly associated risk factors include a positive family history, breech positioning at birth[3]. The diagnosis and management approach for DDH can vary depending on the age at which the condition is detected. The treatment is straightforward and highly effective when DDH is identified early in life[2]. It is diagnosed in early infancy through clinical examinations including tests for joint instability like the Barlow and Ortolani maneuvers these should be conducted on all newborns regardless of risk factors for DDH.

Dynamic ultrasound techniques are also recommended for children with known risk factors who present with normal clinical and static ultrasound findings[4]. Several classification systems exist to categorize hips affected by DDH including the Tönnis, Severin, and Graf schemes, as well as the more recently introduced system developed by the International Hip Dysplasia Institute[5]. The effective management of DDH hinges on early diagnosis and prompt referral to a pediatric orthopedic surgeon[6]. If left undiagnosed and untreated, DDH can result in significant long-term morbidity with severe functional limitations beginning from the walking age and leading to an impaired quality of life. Therefore, early diagnosis and management of DDH are crucial for preventing these debilitating complications[7]. Indeed, the normal development of children's motor skills is a critical area of study. Previous research has found that 25% of children begin walking at 12 months, while 75% have reached this milestone by 14 months. This indicates that an early treatment intervention is crucial in promoting normal motor development in young children.

Furthermore, timely diagnosis of DDH is essential because it can facilitate more effective treatment and reduce the likelihood of complications. Therefore, it is crucial to evaluate the prevalence of DDH because it enables the implementation of prompt detection programs to support anticipation efforts and decrease incapacity and morbidity in impacted children[8]. The epidemiology of DDH has been extensively studied across many countries. Its global prevalence exhibits substantial variation tied to factors such as racial, ethnic, and geography[9,10] with reported prevalence rates spanning from as low as 0.06 per 1000 births up to 34 per 1000 live births[3,11,12]. These wide-ranging epidemiological findings underscore the need for continued research and close monitoring of DDH incidence across different populations.

The incidence across different regions of Saudi Arabia is poorly defined. Previous studies have suggested a relatively high prevalence of DDH in certain parts of the country with one nationwide estimate indicating a rate of 10.46 per 1000 live births[13,14]. The Al Jouf region, located in the northern part of Saudi Arabia, has a unique demographic and cultural profile that may influence the epidemiology of DDH. To date, no studies have yet specifically investigated the prevalence of DDH in this region. Therefore, this cross-sectional observational research aimed to establish the prevalence of DDH in newborns and infants in Al Jouf territory.

MATERIALS AND METHODS

Study design

A cross-sectional analysis was undertaken retrospectively to ascertain the prevalence of DDH in Al Jouf, Saudi Arabia from January 2018 to December 2023.

Study setting

The data for the study were retrieved from the registry of Prince Mutaib Bin Abdulaziz Hospital (Sakaka, Saudi Arabia) as well as maternal and children’s hospitals (Sakaka, Tabarjal and Alqurayyat, Saudi Arabia).

Inclusion and exclusion criteria

Eligible participants were DDH children aged from birth to 14 years old, of both sexes, living in Al Jouf Province. Children were excluded if they had underlying neuromuscular disease, syndromes associated with hip dysplasia, were living outside of Al Jouf Province, or had missing or unavailable data.

Data collection

The data was collected using a predesigned questionnaire, prepared by experts in the field of pediatric orthopedics for its reliability and validity, to collect the data. Cronbach's Alpha test was used to assess the reliability of the questionnaire, and the outcome was 0.89. A pilot study was conducted on 20 records to identify any necessary changes. The data collected included sex, age at diagnosis, and residence.

Sample size calculation

The formula n = z² × p × (1-p) / d² determined the study's sample size with n as the sample size, z as the SD at a 95%CI (1.96), p as the anticipated percentage of the children with DDH, and d as the preferred margin of error. Based on previous studies, the estimated prevalence of DDH in Saudi Arabia is approximately 10.46%[13,14]. The smallest possible sample size was intended as n = (1.96)² × 0.1046 × (1-0.1046)/(0.05)² = 144 participants.

Statistical analysis

The descriptive statistical analysis involved calculating simple frequencies and percentages for the categorical variables such as gender, nationality, and residency. For the continuous variable of age, the mean, median, standard deviation, and range were reported. Additionally, the prevalence of DDH was calculated for the overall Al Jouf province as well as for each city within the province. Inferential statistical methods were then used to investigate the differences in sociodemographic characteristics across the various cities. Fisher's exact test was used for categorical variables. The Shapiro-Wilk Test showed that age data did not follow a normal distribution (P < 0.05), and thus the non-parametric Kruskal-Wallis H test was used for the continuous variable of age. A P value of 0.05 or below was established as the criterion for statistical significance with a 95%CI. The statistical analyses used SPSS Software version 27.0.1 by IBM.

Ethical considerations

Jouf University's Local Committee of Bioethics provided ethical clearance for implementing the study protocol. Permissions were obtained from the administrations of Prince Mutaib bin Abdulaziz Hospital and Maternal and Children’s Hospital to conduct the research at their facilities. The researchers ensured that the study aligned with the ethical standards detailed in the Declaration of Helsinki. The confidentiality of the collected data was strictly preserved, and any potentially identifiable information was omitted from the study proformas.

RESULTS

The registry review identified 427 patients who had been diagnosed with DDH. On average, the patients were 31.3 months old, with a standard deviation of 25.7 months and ages ranging from 1 to 168 months. Females comprised the majority of patients at 79.6% (n = 340); males were 20.4% (n = 87). Most patients, 97.0% (n = 414), were Saudi nationals, while the remaining 3.0% (n = 13) were non-Saudi. These patients were drawn from several cities within Al Jouf province. The largest proportion, 77.8% (n = 332), came from Sakaka, followed by 16.4% (n = 70) from Qurayyat, 4.2% (n = 18) from Tabarjal, and 1.6% (n = 7) from Dumat Al Jandal. No patients were reported from the cities of Suwayr, Abu Ajram, or Meegowa (Table 1).

Table 1 Sociodemographic parameters of children with developmental dysplasia of the hip (n = 427), n (%).

Characteristic	Descriptive
Age (Month)
Mean (SD)	31.3 (25.7)
Range	1-168
Sex
Female	340 (79.6)
Male	87 (20.4)
Nationality
Saudi	414 (97.0)
Non-Saudi	13 (3.0)
City
Sakaka	332 (77.8)
Qurayyat	70 (16.4)
Tabarjal	18 (4.2)
Dumat Al Jandal	7 (1.6)
Suwayr	0
Abu Ajram	0
Meegowa	0

The study examined the prevalence of DDH in the different cities of the Al Jouf province. Sakaka had the highest prevalence, with 332 DDH patients out of 23344 total births, equating to 14.2 per 1000 live births. Qurrayat had the next highest prevalence, with 70 DDH patients out of 32424 births, or 2.2 per 1000. The prevalence was much lower in Tabarjal (0.9 per 1000), Dumat Al Jandal (0.8 per 1000), and the cities of Suwayr, Abu Ajram, and Meegowa, which all had a prevalence of 0 per 1000. Across the entire Al Jouf province, there were 427 DDH patients out of 85140 total births resulting in an overall prevalence of 5.0 per 1000 live births. The birth rate data were obtained from Al Jouf Health Cluster (Figure 1 and Table 2).

Figure 1  Graphical presentation of prevalence of developmental dysplasia of the hip in different cities and the whole province.

Table 2 Prevalence of developmental dysplasia of the hip in different cities of Al Jouf province (n = 427)[1].

City	Percentage	Total births (2018-2023)	No. of patients with DDH	Prevalence (per 1000 live birth)
Sakaka	1.42	23344	332	14.2/1000
Dumat Al Jandal	0.08	8633	7	0.8/1000
Suwayr	0.0	1021	0	0/1000
Tabarjal	0.09	19480	18	0.9/000
Abu Ajram	0.0	78	0	0/1000
Meegowa	0.0	160	0	0/1000
Qurrayat	0.22	32424	70	2.2/1000
Al Jouf province	0.50	85140	427	5.0/1000

DDH: Developmental hip dysplasia.

The study examined the demographic profile of the children with DDH across the cities of the Al Jouf province. The median age of patients varied and ranged from 20 months in Dumat Al Jandal to 24 months in Sakaka, Qurayyat, and Tabarjal; this difference was not significant (P = 0.76). Similarly, the sex distribution showed females comprising most cases ranging from 79.2% in Sakaka to 85.7% in Dumat Al Jandal, but this sex difference was also not significant (P = 0.97) (Table 3).

Table 3 Differences in proportions of developmental dysplasia of the hip by sociodemographic characteristics across different cities (n = 427),n (%).

Demographic		City				P value
		Sakaka	Qurayyat	Tabarjal	Dumat Al Jandal
Age/months (median and IQR)		24 (16-39)	24 (16-47)	23 (12-39)	20 (14-24)	0.76
Sex	Female	263 (79.2)	56 (80.0)	15 (83.3)	6 (85.7)	0.97
	Male	69 (20.8)	14 (20.0)	3 (16.7)	1 (14.3)
Nationality	Saudi	321 (96.7)	68 (97.1)	18 (100.0)	7 (100.0)	0.99
	Non-Saudi	11 (3.3)	2 (2.9)	-	-

IQR: Interquartile range.

DISCUSSION

DDH is the utmost prevailing musculoskeletal condition affecting the hips in young children. From an anatomical perspective, DDH is characterized by a significant misalignment in the placement of the femoral head within the acetabular component of the hip joint. This misalignment results in improper joint formation and function during the critical developmental stages of the hip[15,16]. Determining the incidence and prevalence of this disorder is crucial because it helps national authorities identify demand, allocate resources appropriately, and mobilize necessary interventions[17].

The overall prevalence of DDH in this region was 5.0 per 1000 live births, which is in line with both regional and international estimates. The observed variation in prevalence across countries may be influenced by several factors, including ethnic and genetic differences, disparities in screening protocols, and cultural practices such as infant swaddling. Furthermore, consistent with existing literature, females were more commonly affected than males (Table 4)[17-25].

Table 4 The prevalence of developmental dysplasia of the hip in the literature.

Ref.	Year	Country	Study type	No. of patients	Prevalence/1000 live birth	Female	Male
Mirdad[25]	2002	Saudi Arabia	R	300	3.5	235	65
Almutair[18]	2023	Saudi Arabia	R	212	11.58	134	78
Al Azri et al[17]	2023	Oman	R	795	1.05	652	143
Bialik et al[25]	1999	Israel	P	90	5	-	-
Woodacre et al[22]	2016	United Kingdom	P	182	4.9	159	23
Mace and Paton[23]	2015	United Kingdom	P	201	3.18	145	56
Gyurkovits et al[21]	2021	Hungary	P	55	21.4	45	10
Den and Kokaze[19]	2023	Japan	R	2367	7.59	-	-
Degnan et al[20]	2021	United States	R	6806	1.65	4900	1906

P: Prospective study, R: Retrospective study.

The calculated prevalence of DDH varied across the cities within the Al Jouf province with the estimate for Sakaka governorate being the highest at 14.2 cases per 1000 live births. This finding aligns with a study conducted in Oman, which also found the prevalence of DDH to vary across different regions within the country[18]. The high prevalence of DDH in Sakaka city, in particular, warrants further investigation to identify the underlying risk factors specific to this location. The findings of this study underscore the importance of regional-level epidemiological investigations to capture the nuances in DDH prevalence. Nationwide estimates may mask significant variations within a country, as observed in Saudi Arabia. The lack of DDH cases reported in some Al Jouf cities highlights the need for comprehensive surveillance across all regions to ensure that no population is left unscreened and undiagnosed. Nonetheless, it would be unwise to extrapolate these findings to the broader local population because the data only reflects cases treated within Al Jouf province. Despite this limitation, the results offer a useful starting point and a rough estimate of DDH incidence in the province. The sole method to ascertain the precise incidence would be implementing a comprehensive, prospective large-scale screening program across the entire region.

The prevailing view is that the female sex constitutes a risk factor for DDH, as maternal estrogen released before birth is passed on to female infants. This maternal estrogen exposure is hypothesized to trigger physiological changes and effects analogous to those observed in pelvic relaxation during pregnancy, which may predispose female infants to developing DDH[26].

The results indicate that the condition was more common among female newborns than their male counterparts, though the difference was not statistically significant. This is consistent with prior studies that compared DDH prevalence between sexes[17,18,20-24,26,27].

The mean age of patients with DDH in Al Jouf province ranged between 20-24 months indicating a trend of late presentation. This is consistent with an Indian study that found the average age of the children seeking treatment was over 20 months[28].

Late presentation likely reflects a combination of factors including limited access to comprehensive pediatric screening programs, lack of awareness among caregivers about the importance of early detection, and cultural or socioeconomic barriers that prevent timely medical care. Delayed diagnosis and treatment of DDH can lead to significant long-term consequences, as undetected and untreated DDH during the critical early stages of development can progress to more severe forms of the condition, ultimately requiring more complex and invasive surgical interventions and resulting in worse long-term outcomes. Addressing these root causes is critical to improving the early identification and management of DDH in these populations.

Study limitations

It is important to consider the limitations of this study. First, the study relies on medical records and may have introduced potential biases and underreporting cases, particularly in areas with limited access to healthcare. Second, the study period was limited to 5 years, which may not capture long-term trends and seasonal variations in DDH incidence. Third, the study did not explore the detailed risk factors and associated comorbidities that could have influenced the observed prevalence. Fourth, the outcomes may have been impacted by the fact that many DDH cases from the province are treated outside the area. Finally, this research occurred in a specific area of Saudi Arabia, and the findings may not be generalizable to the entire country or other populations. Future prospective, multi-center studies with longer follow-up periods and a comprehensive assessment of potential risk factors are needed for a more robust understanding of the epidemiology of DDH in the Al Jouf province and beyond.

CONCLUSION

This study provides the first comprehensive assessment of the DDH in the Al Jouf province of Saudi Arabia. The overall prevalence of DDH in the region was 5.0 per 1000 live births with notable variations observed at the city level. The high prevalence in Sakaka and the absence of cases in some cities underscore the importance of targeted screening and early intervention strategies to address this condition effectively. The finding that the mean age of patients with DDH in the Al Jouf province ranged from 20-24 months is concerning because this suggests a pattern of delayed presentation for treatment.

Future research should explore the specific drivers of delayed presentation in greater depth potentially through qualitative studies to better understand the perspectives and experiences of affected families. Developing targeted educational campaigns and optimizing screening protocols within primary care settings may also help to identify DDH cases at an earlier and more treatable stage. Ultimately, collaborative efforts are required to warrant that all infants and young children can obtain timely diagnosis and appropriate treatments for DDH, thus paving the way for enhanced long-term musculoskeletal health. Continued research is justified to better understand the underlying determinants responsible for the epidemiological profiles of DDH in the Al Jouf.

ACKNOWLEDGEMENTS

The author expresses gratitude to the Local Committee of Bioethics at Jouf University for approving the study protocol. Additionally, the author thanks the administration of Prince Mutaib bin Abdulaziz Hospital and Maternal and Children’s Hospital for granting permission to carry out the research at their respective facilities.