Femoral head and acetabular necrosis combined with hip subluxation in people with HIV: a case report and literature review

Abstract

Introduction

HIV is widely prevalent in all regions of the world. The use of antiretroviral drugs has dramatically reduced the mortality rate of HIV-related diseases, but correspondingly increased the incidence of chronic complications in HIV-positive people. Related studies have found that the incidence of osteonecrosis of the femoral head is higher in HIV-positive people, but the co-occurrence of femoral head necrosis, acetabular necrosis and hip joint dislocation in HIV-positive patients is rare.

Methods

We report a 50-year-old man with a 15-month history of progressively worsening right hip pain with movement restriction. According to the CT findings of the other hospital, the patient was admitted to the hospital with femoral head necrosis. After the admission, the relevant X-ray, CT and MRI examinations showed that the right femoral head collapsed and deformed, with the surrounding bone sclerosis, bone fragments, loose body of the joint, right hip subluxation, acetabular marginal osteogeny, and local microcystic degeneration. The left femoral head was in good shape, and cystic degeneration can be seen under the articular surface. The patient was finally diagnosed with femoral head necrosis and acetabular necrosis combined with hip subluxation.

Results

The pain of the patient was significantly relieved after the operation, and the patient was discharged from the hospital one week after the start of treatment to continue rehabilitation training. During the follow-up one month after the operation, the self-reported pain disappeared completely, and the limitation of activity was significantly improved.

Introduction

HIV infection is one of the most important global public health problems. According to the latest statistics from the WHO in 2022, the global HIV infection reached 25.6million people, of which the age group of 15–49 years old infected 0.7% of the population of the same age group. Currently, there is no region in the world that is not affected by the epidemic. WHO data indicate that in 2022, approximately 380,000 individuals died of HIV-related illnesses. HIV enters CD₄⁺T lymphocytes primarily through interactions with CD₄⁺T and the chemokine co-receptors CCR₅ or CXCR₄. The gradual destruction of initial and memory CD₄⁺T lymphocytes is a hallmark of HIV infection [1]. With the gradual depletion of CD₄⁺ T lymphocytes, the body's immune function is continuously declining [2]. It leads to an increased susceptibility of the organism to various diseases. In the past three decades, although mortality from HIV-related diseases has decreased due to the use of highly effective antiretroviral agents [3], the prolongation of survival has led to an increase in the incidence of various chronic complications. Osteonecrosis is one of them. The incidence of osteonecrosis of the femoral head is at least 10 times higher in HIV-infected patients than in the general population [4]. Related studies have shown that this may be related to the interference of HIV and HAART on bone metabolism [3, 5]. The main symptom of patients who develop osteonecrosis of the femoral head is sudden pain in the hip, and the range of motion of the joint usually remains the same in the early stage and progressively deteriorates in the later stages of the disease. Whereas, among the 206 patients studied by Lima et al., all patients diagnosed with osteonecrosis were in an advanced stage of the disease. For patients with advanced femoral head necrosis, joint replacement is the best option, but total hip arthroplasty (THA) aggravates the burden of the majority of HIV-infected patients [6, 7]. This case presents an exceptional case of femoral head necrosis and acetabular necrosis complicated with hip subluxation joint in patients with HIV infection.

Case report

A 50-year-old man was admitted to Beijing Ditan Hospital in February 2024 with necrosis of the femoral head because of "right hip pain with limitation of movement for 15 months, aggravated for 3 months". He was diagnosed with "reflux esophagitis", had a penicillin allergy, and was identified with HIV infection three years ago in "731 Hospital" during laboratory tests for perianal abscess, with no history of hypertension, diabetes mellitus, or hepatitis.

The patient experienced right hip pain 15 months ago as a result of a sprain, which worsened while walking. Thus, he was consulted at Hospital 309, and a CT scan reveal no obvious fracture or osteonecrosis, so the patient was given pain relief and symptomatic treatment. 11 months ago, after symptomatic treatment for 4 months, the pain was not significantly relieved. As a result, the patient returned the 309 hospital again and got an MRI examination, which suggested that the right femoral head was necrotic, and then symptomatic treatment for pain relief was administered again. Nine months ago, the patient was treated in Beijing Jishuitan Hospital for right hip pain. Based on past examination results, the doctor recommended that pain relief be continued. Three months ago, the pain of the right hip worsened and the walking activities were clearly restricted, so he had to work with crutches. In order to seek further diagnosis and treatment, the patient came to our hospital 1 month ago. According to the prior examination, the diagnosis of the osteonecrosis of the femoral head and HIV infection is clear. Then, the patient was admitted to the hospital. When the patient attended our hospital, they showed no clinical signs of chronic infection, such as long-term fever, heavy sweating, exhaustion, muscle and joint pain, or enlargement of the liver, spleen, or lymph nodes. Furthermore, there were no signs of persistent infection from previous hospital visits before being admitted to our facility. After admission, all liver enzyme markers were normal, and the diagnosis of AIDS and femoral head necrosis was established, thus no further cultures or tissue pathology tests were conducted.

On the first day of admission, the following positive signs were found in the specialized examination: swelling of the proximal right thigh, obvious pressure pain in the right hip, obvious axial percussion pain, obviously limited movement, and shortening of the right lower limb by 3.0 cm in comparison to the left lower limb. After admission, in order to clarify the progress of the disease, MRI of the hip joint was perfected (Fig. 1), Fig. 1a is a T1W1 image, Fig. 1b is a T2W1 image, arrows 1,3 showed that the right femoral head collapsed, fissure, the femoral neck shortened, acetabular rim sclerosis, articular cavity effusion; arrows 2,4 showed high T1W1 and low T2W1 in the patchy center of the left femoral head, while T1W1 and high T2W1 in the marginal bands; the femur is not collapsed, the joint is in position,and there is no narrowing of the joint space. Preoperative lower limb CT scan (Fig. 2 a, b) showed that the right femoral head is collapsed and deformed, with sclerosis of the surrounding bone, bone fragments and articular free body can be seen, the right hip joint is subluxed, and the acetabular rim is osteophytic, with a small localized cystic degeneration. The left hip joint is in position with joint space.

Fig. 1

Preoperative MRI image of the hip joint. a is a T1W1 image and b is a T2W1 image

Fig. 2

CT image of the hip joint. a and b are the preoperative CT image. c and d are the postoperative CT

The test indices after admission are shown in Table 1 (2.26), the basophil count and percentage of basophils were elevated, indicating that the patients could have an infectious state, but the leukocytes were not significantly elevated and the percentage of lymphocytes was relatively low, which might be related to the fact that HIV attacked the T-lymphocytes and the body's immune function was impaired. This argument was also supported by the abnormality in the ratio of CD4 to CD8.

Table 1 Laboratory tests results of the patient

In view of previous symptomatic pain management with poor results, total hip arthroplasty was performed. Make the patients take the left recumbent position, and a modified Gibson approach was taken to the right posterior lateral hip, and the skin, subcutaneous and deep fascia were incised layer by layer. The bursa of the greater trochanter was excised, and the gluteus maximus fibers were separated along the muscle fibers. The bursa of the greater trochanter was excised, and the gluteus maximus muscle fibers were separated along the muscle fibers. The lower limbs were straightened and internally rotated to expose the external circumflex muscles at the posterior stop of the greater trochanter, and the piriformis, gemellus superior, obturator internus, gemellus inferior and part of the quadratus femoris are cut along the posterior edge of the greater trochanter, and then drawn posteriorly to expose the joint capsule, which is incised. Make the hip joint flexion, adduction and internal rotation. And dislocate the hip joint. According to the preoperative design, the femoral neck was amputated about 1.2 cm above the lesser trochanter, and the femoral head was removed, and the necrotic femoral head was seen to be collapsed and fractured. The surrounding tissues were retracted to expose the acetabulum, and the periacetabular bony cumbers and soft tissues within the acetabulum were removed. We protected the transverse acetabular ligament when we removed the lip of the acetabulum.

During the surgical procedure, we encountered a minor issue. To ensure a proper fit between the acetabulum and the custom-made femoral head, we removed the osteophytes around the acetabulum and the surrounding soft tissues. Our team repeatedly placed the artificial femoral head to test its mobility within the acetabulum and the degree of fit with it. Based on the surgeon's experience, we then repeatedly filed down the acetabulum until a proper match was achieved. The acetabulum was filed from tiny to large with an acetabular file to a size of 50 mm, until the subchondral bone was revealed. There was punctate oozing of blood from the bone bed. The file is satisfactory and the size of the implanted 50 mm is appropriate. The incision was rinsed, hemostatic gauze was used to stop the bleeding, and a 50 mm uncemented external cup was implanted with a built-in ceramic liner. The pressing fitting is good, and the valgus angle and forward inclination angle are contented. No screws were used for auxiliary fixation.

The cotter is opened along the direction of the femoral bone marrow cavity, the medulla is expanded number by number, and the marrow cavity of the femur is filed with the use of a medullary file to the 12th shank, which is satisfactorily compressed and fitted. The osteotomy surface of the proximal femur can be repaired satisfactorily with a flat-head file, and we found it is more appropriate to implant the test die with reduced head through trialing the mold head.The medullary cavity was flushed, a non-cement femoral stem prosthesis was implanted, the torsion test was negative, and a ceramic femoral head prosthesis was installed. Then reposition the joint and check for flexion, extension, retraction and rotation movements of the joint, which were satisfactory. And the joint is stabilized. The postoperative tests of the patients are detailed in Table 1. Due to the fact that the organism is in the stage of postoperative recovery, the inflammatory indexes are slightly increased. The postoperative CT of the hip joint of the patient was the manifestation of total hip arthroplasty (Fig. 2 c, d). We make a postoperative telephone follow-up which showed that the pain of the hip joint was significantly relieved and the limitation of movement was apparently improved. Informed consent was obtained among patients for this case report, and ethical approval was granted by Beijing Ditan Hospital.

Discussion

In recent years, with the application of highly active antiretroviral (HAART), HIV infection has become a chronic disease, but with a corresponding increase in the incidence of other complications [8]. The research of Morse et al. showed that the risk of osteonecrosis in adults infected with HIV was 100 times higher than that in normal people [9]. Humeral epiphysis, femoral head and femoral condyle are often involved [10]. Osteonecrosis-related pain, osteomalacia, increased risk of fracture and limited activity in advanced patients greatly reduce the quality of life of people infected with HIV [11]. Related studies have shown that HIV can promote osteoclast formation and osteolytic activity by infecting osteoclast precursor cells. At the same time, HIV could destroy osteoblasts and their progenitor cells, and accelerate the senescence of mesenchymal stem cells [12]. Following the introduction of HAART into clinical care, the incidence of osteonecrosis increased [13]. The antiretroviral drugs tenofovir (TDF) and protease inhibitors were found to be independent risk factors for osteonecrosis of the femoral head [14, 15]. These may be related to the abnormal metabolism of blood lipids and vitamin D caused by HAART [13]. However, no clear mechanism has been confirmed. Thus, further research is needed to understand the pathogenesis of osteonecrosis in patients with HIV infection and to identify effective treatments.

The incidence of osteonecrosis of the femoral head is higher in HIV positive patients with hip pain. At present, there are no reports of acetabular necrosis or hip subluxation in HIV-positive individuals. The combination of necrosis of the femoral head and acetabular necrosis reported in this case with hip joint subluxation is even rarer.

Hip subluxation is a type of hip instability. The hip joint has historically been considered to be highly stable, with the high degree of bone congruence between the femur and the acetabulum providing inherent stability for the hip joint. The iliofemoral ligament, ischiofemoral ligament and pubic femoral ligament around the hip joint provide a guarantee for the stability of the hip joint during exercise [16, 17]. Hip instability can be caused by both traumatic and non-traumatic factors [18]. Traumatic factors include high-energy sports injuries, iatrogenic injury and accidental injury, while non-traumatic factors include congenital hip dysplasia, hip impingement syndrome and other systemic conditions and bone structure changes [19, 20]. In this case, necrotic collapse of the right femoral head and necrosis of the acetabulum resulted in decreased anastomosis with the acetabulum, progressive changes in the intrinsic bony stabilizing structures of the hip joint, and changes in the anteversion of the femur, which led to the transfer of the mechanical axis from the center of the femoral head, which subsequently led to the subluxation of the acetabulum. HIV caused the dysregulation of OPG/RNAKL/RANK system, increased the activity of osteoclasts and destroyed osteoblasts and their progenitor cells [12]. The bone mineral density of HIV positive patients is decreased, and the stability of bone structure is lower than that of normal people, and the risk of fracture is increased [21]. This may be one of the reasons for the hip subluxation that occurred in this patient.

The causes of acetabular necrosis include ischemic osteonecrosis and acetabular necrosis caused by advanced osteoarthritis. There are many reports of avascular non-traumatic necrosis of the femoral head. In contrast, avascular osteonecrosis of the acetabulum is rare. If the acetabulum shows uneven acetabular density on X-ray, with cystic lesions in most of the acetabulum and periacetabular sclerosis, then ischemic acetabular necrosis can be highly suspected [22]. Acetabular necrosis due to advanced osteoarthritis requires the corresponding X-ray manifestations of advanced osteoarthritis: narrowing of the joint space, cystic degeneration with a smooth and clear edge around the acetabular or femoral head, and is often seen in the elderly [23, 24]. In this case, acetabular necrosis is more inclined to ischemic osteonecrosis. Avascular necrosis of the femoral head combined with acetabular ischemia is uncommon. Related studies have shown that acetabular necrosis is a separate disease from osteonecrosis of the femoral head, and the use of steroids is a common risk factor for both [22].

Additionally, Rheumatoid Arthritis (RA), as a chronic inflammatory autoimmune disease, can also affect the hip joint in severe cases. In a prospective cohort study of rheumatoid patients in Finland, approximately 20% of patients had hip joint involvement [25]. After being affected, it can manifest as hip pain and limited function. Depending on the severity of the disease, X-rays may show narrowing of the joint space, destruction of the femoral head, and protrusion of the acetabulum [26]. These symptoms and radiological changes are similar to the hip necrosis related to AIDS in this case. However, RA usually has a history of chronic symmetric arthritis, often accompanied by generalized pain and swelling in multiple small joints and morning stiffness, and is specific for positive laboratory tests for anti-cyclic citrullinated peptide antibodies (anti-CCP antibodies) and rheumatoid factor (RF) [27]. Based on the above points, it is easier to differentiate it from AIDS-associated necrosis of the hip.

In this case, the application of antiretroviral drugs had an effect on bone metabolism, which may be related to osteonecrosis of the femoral head and acetabulum, and then the inherent bony stable structures of the hip joint were disrupted, resulting in the occurrence of subluxation of the hip joint. The simultaneous occurrence of necrosis of the femoral head and acetabulum with subluxation of the hip is clinically rare. At present, there are no identical cases to draw upon for reference, but based on past treatment experience with femoral head necrosis in HIV-positive patients, conservative pain relief treatment for this patient is no longer alleviating the condition. Severe joint pain and functional impairment have significantly affected the patient's daily walking. Moreover, this patient's CD4 + T cell count was relatively high upon admission, indicating a lower surgical risk. Our team therefore decided to perform total hip replacement surgery for the patient [28].

Total hip replacement surgery is currently a known effective treatment for patients with femoral head necrosis. However, in this case, it was applied to a patient with combined hip dislocation and acetabular necrosis. To date, the patient has not experienced severe complications and the quality of life has significantly improved. Our team hopes that this case will provide a reference for clinical diagnosis and treatment, and raise awareness of such complex hip joint diseases. Due to the short follow-up period, the long-term prognosis and potential complications of the total hip replacement surgery for this patient have not yet been identified, but this also provides a direction for future research.