Hip, hip, hooray! Athletes don’t have to call it a day

A: Anteroposterior X-ray of a normal acetabular roof. Note that weight bearing forces (blue arrows) are applied over the entire surface. B: Dysplastic shallow acetabular roof with weight bearing forces distributed over a smaller area.

Prolonged maligned contact also leads to chronic changes like hypertrophy of the capsule and ligament teres and forming a thickened acetabular edge^(2,3). These changes further affect joint congruency and prevent the appropriate relocation of the femoral head. As a result, DHD includes unstable hips, malformed acetabula, subluxation, and dislocation (see figure 2).

Figure 3a: A-P X-ray indicating the LCEA used to diagnose the severity of hip dysplasia

Figure 3b: Coronal MRI image reveals an enlarged lateral labrum with substantial deterioration (black arrow) and subchondral changes in the femoral head (white arrows)

Figure 3c: 3D CT images further illustrate the combined pattern of cam and femoral coverage.

The diagnosis of DHD-related bony dysmorphism is not always clear. In addition, hybrid conditions may exist with varying degrees of dysplasia, chondolabral pathology, and femoroacetabular impingement^(3,5). Therefore, determining the underlying etiology and most appropriate intervention can be challenging.

Diagnosis

A complete medical history, physical examination, and X-ray or MRI evaluation are required to diagnose symptomatic hip dysplasia and other associated pathology. Some athletes may have a treatment history for hip problems as an infant or child. However, symptoms may recur in adulthood if there is some remaining deformity. Common symptoms of hip dysplasia include:

• Intermittent pain in the groin, hip, buttock, and thigh. The pain usually subsides with rest.
• A sensation of catching, popping, clicking, or giving way with activity.
• Worsening pain with sitting, walking, or running
• Limping
• Increased difficulty with strenuous activities

On X-ray examination, clinicians assess several angles to measure femoral coverage. For example, a lateral center-edge angle (LCEA) of less than 20° is defined as severe dysplasia, 20-25°  degrees, borderline dysplasia, and >25°is normal⁽⁷⁾. Additional CT or MRI scans are required for a thorough diagnosis of associated pathology not visible on X-ray (see figure 3).

A: X-ray of an 18-year-old male patient with acetabular dysplasia (shallow socket) of both hips before PAO.

B: X-ray of both hips in the same patient after correction of the shallow sockets with PAO surgery. Note the improved coverage of the femoral head.

Image sourced from: www.ortho.wustl.edu/content/Patient-Care/3205/Services/Hip-Knee/Adult-Reconstruction-and-Hip-Preservation-Overview/Hip-Dysplasia.aspx

Treatment

Depending on the severity of DHD-related symptoms and dysfunction, associated pathology, the disorder progression, and the patient profile, rehabilitation with or without surgery is a treatment option. The primary treatment goal is to obtain a concentrically positioned femoral head into the acetabulum, structuring or stimulating the latter to adapt normally. 

Surgical intervention

Clinicians may consider joint preservation surgery if hip dysplasia is diagnosed early (before osteoarthritis). However, if hip dysplasia is diagnosed later in the disease process and osteoarthritis is present, joint preservation surgery may not be an option, and clinicians may consider a total hip replacement (THR). Notably, DHD is the main cause of THR in younger athletes. A periacetabular osteotomy (PAO) is the preferred surgical intervention for symptomatic DHD^(6,8). A PAO is an open surgery that re-orientates the dysplastic acetabulum and may provide a lifelong solution for symptomatic dysplasia (see figure 4)^(6,8). Most athletic patients undergoing PAO are female and show postoperative improvements in function and return to athletic play⁽⁶⁾. 

Considering the associated structural pathology, it is essential to differentiate the principal etiology of joint pain and subsequent dysfunction in athletes. Clinicians can use arthroscopy to correct borderline dysplasia and femoral acetabular impingement (FAI) while correcting severe dysplasia requires an open procedure^(3,8). Successful outcomes are achieved with arthroscopic correction of FAI, and athletes’ probability of returning to sports is high. However, inappropriate arthroscopy in the presence of dysplasia can lead to direct surgery-related instability and potentially unfavorable consequences⁽³⁾.

Rehabilitation

Post-hip arthroscopy rehabilitation can start as early as one day after surgery. Depending on the extent and type of the procedure, rehabilitation programs should be tailored to meet the individual’s needs. Patients use crutches to limit weight bearing and a brace for stability to limit flexion to 90° and extension to 0°^(9,10). A daily stationary bicycle is recommended for eight weeks post-operatively, after which clinicians can progressively include impact-type exercises such as jogging.

Researchers at the Aarhus University Hospital in Denmark conducted an eight-week supervised progressive resistance training program to increase muscle strength and induce muscle hypertrophy for patients with dysplasia awaiting POA surgery⁽¹¹⁾. The program included 3-4 sets of 8-12 repetitions of exercises, such as the leg press, hamstring curl, knee extension (all performed double-legged), hip flexion (single-legged), and lunges⁽¹¹⁾. The study results demonstrate that supervised progressive resistance training is viable in improving pain, functional, muscle strength in patients with hip dysplasia⁽¹¹⁾. However, this study included a non-athletic population.

Inadequate rehabilitation after PAO may lead to poor outcomes, including prolonged impairments in hip strength⁽¹²⁾. Therefore, developing standard PAO rehabilitation programs is vital for achieving optimal outcomes. A panel of experts in North America developed rehabilitation guidelines for use following a PAO (see table 1)⁽¹²⁾.

Table 1: Rehabilitation guidelines post PAO surgery⁽¹²⁾

Conclusion

Hip dysplasia is usually a progressive condition that worsens with time. Hip pain, dysfunction, and activity limitations worsen as the condition progresses. Therefore, early diagnosis and consideration of different treatment options are important. Athletes generally respond well to arthroscopic and PAO surgery combined with rehabilitation and can return to high-level competition post-operatively.

References

1. Children. 2022;9(2):247.
2. Developmental Dysplasia Of The Hip. StatPearls Publishing; 2022.
3. J Hip Preserv Surg. 2017;4(4):332-336. doi:10.1093/jhps/hnx028
4. Sports Health Multidiscip Approach. 2015;7(4):346-358.
5. BMJ Open Sport Exerc Med. 2021;7(4):e001169.
6. Am J Sports Med. 2016;44(6):1573-1581.
7. Am J Roentgenol. 2013;200(5):1077-1088.
8. Am J Sports Med. 2014;42(8):1791-1795.
9. Am J Sports Med. 2021;49(9):2447-2456.
10. EFORT Open Rev. 2019;4(9):548-556.
11. J Rehabil Med. 2018;50(8):751-758.
12. Int J Sports Phys Ther. 2022;17(6). doi:10.26603/001c.38043