Multiple revision surgeries after total hip arthroplasty in a patient with osteopetrosis: a case report with 24 years of follow-up

Abstract

Osteopetrosis, also recognized as marble bone disease, denotes a rare hereditary skeletal condition. It is distinguished by faulty osteoclast resorption, resulting in universally rigid and brittle bones. Secondary osteoarthritis often occurs in young and middle-aged patients with osteopetrosis. They often have to have joint replacement surgery at a young age, which means they will likely face multiple revision surgeries. To draw attention to revision surgery, we present the case of an osteopetrosis patient who underwent multiple revision surgeries after total hip arthroplasty. Additionally, we suggest that this may be the first reported case of revision surgery utilizing a custom triflange acetabular component (CTAC) in a patient with osteopetrosis. These findings will offer valuable insights for selecting appropriate techniques and instruments for multiple revision surgeries of total hip arthroplasty in patients with osteopetrosis. Presently, total hip arthroplasty remains a valuable treatment option in osteopetrosis patients when executed with precision.

Introduction

Osteopetrosis, also recognized as marble bone disease, is a rare hereditary skeletal condition initially delineated in 1904 by Albert-Schonberg, a distinguished German radiologist [1]. It is distinguished by faulty osteoclast resorption, which results in universally rigid and brittle bones [2].

Osteopetrosis has been categorized into three manifestations: (1) an autosomal recessive manifestation, (2) an intermediate autosomal recessive manifestation, and (3) a benign autosomal dominant (ADO) manifestation [3]. The sex-linked recessive variant is linked to childhood adversities and premature mortality. Conversely, the autosomal dominant variant is compatible with a normative lifespan, with up to 40% of patients potentially remaining asymptomatic [4]. The ADO variant can further be subdivided into two subtypes (I and II) [5]. The ADO type I variant manifests as heightened cranial vault thickness, diffuse osteosclerosis of the lumbar spine and pelvis, and symmetrical involvement of long bones. Conversely, the ADO type II variant entails more extensive basal skull involvement, a'rugger-jersey'spine, and the presence of'endobones'within the pelvis [6]. Moreover, type II patients are more prone to frequent fractures, coxa vara, long-bone bowing, osteomyelitis, osteoarthritis, and nonunion of fractures [3].

In patients with ADO type II, hip joint osteoarthritis arises due to the compression of articular cartilage by unyielding subchondral bone [5]. Cases of symptomatic hip joint osteoarthritis in the ADO type II variant may necessitate total hip arthroplasty (THA) if analgesic interventions prove ineffective [3]. However, post-total hip arthroplasty revision surgery is frequently overlooked owing to the positive outcomes in the short and medium term following primary total hip arthroplasty in osteopetrosis patients [7]. Patients with osteopetrosis exhibit a high rate of reoperation [7]. Furthermore, revision surgery in osteopetrosis patients is rendered more challenging and complex due to the density and fragility of the bone [8]. To draw attention to revision surgery, we present the case of an osteopetrosis patient who underwent multiple revision surgeries after total hip arthroplasty. Additionally, we suggest that this may be the first reported case of revision surgery utilizing a custom triflange acetabular component (CTAC) in a patient with osteopetrosis.

Case report

A patient afflicted with osteopetrosis, having undergone total hip arthroplasty, presented at our medical facility due to aseptic loosening of the left THA. This individual, a 62-year-old gentleman, boasts a medical history replete with numerous instances of revision surgeries (Fig. 1). The patient underwent a comprehensive periprosthetic joint infection (PJI) examination, which conclusively excluded PJI. The genesis of this medical journey traces back to 1976 when he experienced bilateral hip pain, leading to an osteopetrosis diagnosis at a local hospital. The patient sought treatment at various medical facilities. In 2000, bilateral total hip arthroplasty was performed to address worsening osteoarthritis in both hips (Fig. 2A-B), significantly alleviating hip pain. After this, the patient underwent revision surgery for the right total hip arthroplasty in February 2009 (Fig. 2C-D) and another for the left in July 2009 (Fig. 2E-F), tackling bilateral acetabular cup loosening, and the patient suffered a periprosthetic femoral fracture in the right revision surgery.

Fig. 1

Follow-up flowchart of the patient with osteopetrosis, the time of each surgery has been marked with a bold black box. CTAC: custom triflange acetabular component

Fig. 2

A – N depicts a follow-up series of anteroposterior (AP) radiographs in a patient with osteopetrosis. Refer to the follow-up flowchart of the patient with osteopetrosis for detailed annotations

A subsequent consultation in March 2015 at another medical institution revealed significant pain and reduced range of motion in the right hip. Physical examination disclosed limited flexion, extension, abduction, adduction, and rotational movements in the right hip. The radiographic assessment indicated the aseptic loosening of the cup in the right THA (Fig. 2G). Subsequently, the patient underwent revision surgery for the right total hip arthroplasty (Fig. 2H).

The surgical procedure was executed through a posterolateral approach, revealing intraoperative observations of the dislodgment of the polyethylene acetabular cup and the loosening of the femoral component. The artificial femoral head was removed, and the femoral component was extracted. Subsequently, a chisel was employed to disintegrate the cement within the medullary cavity, followed by progressively larger hammer files to enlarge the cavity until a snug fit with a #9 hammer file. Additionally, the intact socket cup prosthesis was removed, unveiling a substantial bone defect in the acetabulum. The acetabular cavity was expanded to 52 mm through progressively larger acetabular reamers, accommodating a 52 mm jumbo cup (Smith & Nephew, English). Four screws were then inserted to secure the jumbo cup. Following this, an allograft bone strip was implanted along the exterior of the acetabular cup prosthesis above the cup, and a 52-mm polyethylene liner was placed. Ultimately, a #9 cemented femoral component (Smith & Nephew, English) was affixed with bone cement, and a 28 mm/− 3 mm metal femoral head was installed.

In July 2023, the patient encountered distress accompanied by a diminished range of motion in his left hip, prompting his visit to our medical facility. Upon physical examination, the left hip manifested 80° of flexion coupled with 5° flexion contracture, 25° of abduction, 20° of adduction, 5° of internal rotation, and 5° of external rotation. Conversely, the right hip exhibited 90° of flexion, 0° of extension, 35° of abduction, 20° of adduction, 15° of internal rotation, and 20° of external rotation. Preliminary radiographic analysis revealed the loosening of the acetabular prosthesis following left hip arthroplasty (Fig. 2I). Consequently, the patient underwent surgical intervention, encompassing left acetabular reconstructive surgery and revision of the acetabular prosthesis (Fig. 2J).

The surgical procedure, conducted via a posterolateral approach, entailed hip dislocation, removal of the metal femoral head prosthesis, and subsequent discovery of significantly loose and displaced acetabular prosthesis. After meticulous removal, the acetabular cavity was enlarged to 54 mm using acetabular reamers. A trabecular metal augment was affixed to the top medial aspect of the acetabulum with two screws. A 54-mm acetabular cup prosthesis was then implanted, accompanied by another trabecular metal augment on the top lateral aspect. The acetabular cup prosthesis (Stryker, America) and the two trabecular metal augments (AKMEDICAL, China) were secured with bone cement. Subsequent steps involved the placement of a ceramic liner (Stryker, America) and fitting a + 5 mm #36 ceramic femoral head (Stryker, America), culminating in the reduction of the hip joint.

Regrettably, following the surgery, the patient manifested ptosis in the left foot and lesser toes, accompanied by an inability to dorsiflex the left foot. During this period, it was conjectured that these symptoms might be attributed to traction on the common peroneal nerve. Consequently, the patient underwent a regimen including mecobalamin for neuro-nutrition, mannitol for detumescence, monosialotetrahexosylganglioside, methylprednisolone, and acupuncture. The standard rehabilitation protocol for total hip arthroplasty (THA) was also diligently implemented in the postoperative phase. After discharge, the patient persistently adhered to the use of mecobalamin.

The patient manifested loosening of the left acetabular prosthesis a fortnight postoperatively (Fig. 2K). Recognizing the challenges of a subsequent revision, we employed a custom triflange acetabular component (CTAC) for the corrective procedure (Fig. 3A-B). A meticulous thin-layer CT scan was dispatched to the manufacturer to tailor a triflange titanium acetabular component (Fig. 3C) and a one-to-one scale three-dimensional (3D) model of the hemipelvis (Fig. 3D). The construction of a 3-D model proves instrumental for the categorization and preoperative strategizing of intricate acetabular reconstruction [9]. In order to customize the prosthesis and model, the patient underwent a three-month waiting period, refraining from weight-bearing on the left lower limb throughout this period. Three months later, the preoperative radiograph of the patient suggested that the left acetabular prosthesis loosening and Screw breakage (Fig. 2L). We then performed revision surgery on the left hip (Fig. 2M).

Fig. 3

Demonstrates: (A, B) Surgical plan for custom triflange acetabular component (CTAC) implantation. Some of the nail holes are spare; (C) Proposed design for the implant; (D) A One-to-one scale three-dimensional (3D) model of the hemipelvis

The surgical intervention transpired through a posterolateral approach. After incising the joint capsule, we dislocated the hip and removed the metal femoral head prosthesis. Subsequent steps involved the extraction of the loose acetabular prosthesis, trabecular metal augments, and screws. Intraoperatively, the discovery was made that the sciatic nerve was partially enveloped by scar tissue, necessitating the judicious separation of the sciatic nerve from the scar tissue. Following this, the acetabular cavity was expanded to 54 mm using acetabular reamers. However, upon assessing the model, it was discerned that the acetabulum still presented extensive bone defects. To address this, two allograft femoral heads were implanted. Subsequently, the customized cup (AKMEDICAL, China) was securely fastened with seven screws (Fig. 4), and subsequently, the cup underwent fortification with bone cement. Lastly, a polyethylene liner (AKMEDICAL, China) was positioned, a 28-gauge ceramic femoral head (Stryker, America) was installed, and the reduction of the hip joint was skillfully executed.

Fig. 4

Illustrates the custom triflange acetabular component (CTAC) implanted in the hip

The patient was not allowed to bear weight for the first 3 months postoperatively. Moreover, after 3 months, the patient began partial weight-bearing with a standard walker. In the fourth postoperative month, the patient was walking without pain with a standard walker, and plain radiograph showed the initial union of the bone (Fig. 2N). Her Harris hip score at 4 months was 67.25 of 100. Unfortunately, the patient could still not perform active dorsiflexion and extension of the left ankle joint and had plantar numbness. Subsequently, we had the patient wear a custom ankle–foot-orthosis (AFO) to prevent Achilles tendon contracture and aid in walking, and kept the patient taking mecobalamin.

Discussion

Patients exhibiting ADO type II typically manifest hip osteoarthritis beyond the age of 40. This osteoarthritis ensues from the compression of articular cartilage by unyielding subchondral bone [2]. In cases where conservative treatments do not provide sufficient relief, total hip joint arthroplasty (THA) may be considered. The decision to proceed with surgery hinges on the severity of arthritis, the patient's age, and overall health. Studies indicate that for individuals undergoing primary total hip arthroplasty surgery under 60, there is a significant escalation in the lifetime risk of revision [10, 11], signifying a predisposition to multiple revision surgeries.

Osteopetrosis-afflicted patients are prone to fractures and nonunion due to osteoclast dysfunction and pathological bone remodeling [2]. Challenges such as dense, brittle bones, heightened fracture risk, impaired bone healing, and difficulties in implant fixation intensify the likelihood of further revisions. The dense bone quality associated with osteopetrosis poses complications in initial and subsequent THA surgeries, potentially necessitating additional revisions. While complications linked to osteopetrosis may elevate the probability of revision surgeries in total hip arthroplasty (THA), specific data directly correlating osteopetrosis to THA revision rates remain limited due to its rarity and varied cases.

In our case, a cemented acetabular component was employed. Cement components can offer immediate stability, as cement aids in establishing robust initial fixation. However, the enduring durability of the cement–bone interface may be compromised in osteopetrosis patients [12]. Over time, dense bone and potential challenges in achieving proper cement penetration may weaken this interface. Although there are no documented instances of loosening of cemented acetabular components in THA with osteopetrosis [3], existing reports primarily encompass short- or medium-term results.

Unexpectedly, the cemented acetabular component in our case proved less stable than anticipated. The patient experienced multiple instances of acetabular loosenings and underwent numerous revision surgeries over the 23-year follow-up period. This data is indeed concerning. Our intention is not to disparage cemented acetabular components but rather to draw attention to the issue of revision surgery following total hip replacement in patients with osteopetrosis. Frequent revision surgeries substantially harm patients and escalate the financial burden on the healthcare system [13].

Regrettably, a definitive resolution to the recurrent issue of revision surgeries following total hip arthroplasty remains elusive. To propel advancements in this research domain, we propose pertinent research directions. Presently, no disease-specific treatment for ADO exists [14]. The realm of internal medicine treatment retains substantial potential for exploration. Early and efficacious drug therapy can potentially delay or prevent the occurrence of osteoarthritis in osteopetrosis patients. In the realm of surgery, meticulous attention to surgical technique remains paramount until advancements in surgery-related materials and instruments are achieved [3]. THA remains commendable among the available surgical modalities, contingent on precise preoperative planning, specialized surgical techniques, and tailored rehabilitation [3].

Revision total hip surgery in osteopetrosis patients proves challenging due to abnormal bone structure and increased bone density. In our case follow-up, the patient presented with numerous acetabular prosthesis loosenings and underwent repeated acetabular prosthesis revision surgeries. For instance, concerning the left hip, the patient experienced acetabular prosthesis loosening nine years post-initial total hip arthroplasty and underwent revision surgery of left total hip arthroplasty. Considering the challenge of bone ingrowth in osteopetrosis patients, a cemented hemispherical cup was utilized for the revision surgery. Fourteen years later, the patient faced renewed loosening of the left acetabular prosthesis, with substantial bone defects in the acetabulum and an upward displacement of the center of rotation. To address this, trabecular metal augments were incorporated for the revision surgery.

Research indicates that employing trabecular metal augment in complex acetabular reconstruction yields favorable outcomes in short to medium term. Noteworthy studies [15, 16] reported promising results in acetabular revision using a combination of a trabecular metal shell and augment, indicating high overall survival of the acetabular component. However, it is crucial to acknowledge that these results are not specific to osteopetrosis patients. Outcomes of acetabular revision surgery in osteopetrosis patients may fluctuate based on the severity of the disease and individual patient factors. In our case, the patient encountered acetabular prosthesis loosening two weeks after revision surgery and a screw fracture two months after revision surgery. This may be attributed to the low adhesion quality and penetration between bone and cement due to excessively dense bone [3]. Additionally, the deviation of screws from the direction of load transfer could be a potential factor in acetabular prosthesis loosening [15].

Confronted with a complex case involving a considerable acetabular bone defect and numerous revisions, we chose a custom triflange acetabular component (CTAC) for the revision surgery. Studies affirm that the use of CTAC in revision THA for substantial peri-acetabular bone defects demonstrates satisfactory complication and implant failure rates [17]. A study [18] also reported that 95% of 40 CTAC cases functioned optimally at an average of 10 years post-revision THA. Considering the difficulty of bone ingrowth in patients with osteopetrosis, we prolonged the period of non-weight-bearing. We had the patient partially weight-bearing with a standard walker for 3 months after surgery. The patient's short-term clinical prognosis was generally satisfactory. However, ongoing observation is necessary to evaluate the patient's mid- and long-term prognosis. Additionally, this may be the first reported case of revision surgery employing a CTAC in a patient with osteopetrosis. These findings will offer valuable insights for selecting appropriate techniques and instruments for multiple revision surgeries of total hip arthroplasty in patients with osteopetrosis.

The application of the CTAC in total hip replacement revision surgery for patients with osteopetrosis presents a novel solution for managing extensive acetabular defects and complex pelvic discontinuities. However, it is accompanied by several limitations and potential risks. Firstly, CTAC implantation is a highly intricate procedure demanding meticulous preoperative planning and precise intraoperative execution; any deviation may compromise prosthetic stability or lead to complications. Secondly, the surgery carries a high complication rate, including screw loosening, pelvic fractures, wound leakage, and hip dislocation [17]. Furthermore, impaired bone healing in patients with osteopetrosis exacerbates the risk of surgical complications. Additionally, the substantial costs of CTAC design and production restrict its widespread adoption. Lastly, long-term follow-up data on CTAC in patients with osteopetrosis remain limited, leaving its long-term outcomes and prosthetic survival rates uncertain. Therefore, clinical application must consider patient-specific factors, and CTAC should be cautiously selected as a revision option for patients with osteopetrosis.

In summary, the optimal therapeutic approach for osteopetrosis with total hip arthroplasty (THA) is presently indeterminate, given the scarcity of comprehensive studies on the enduring consequences and associated complications of THA in osteopetrosis. Individuals with osteopetrosis post-THA may encounter multiple revisions during extended follow-up periods. Despite the absence of a definitive solution at present, THA persists as an exceedingly valuable methodology for mitigating hip discomfort and enhancing patient functionality when executed with precision. Consequently, when contemplating THA for osteopetrosis, the orthopedic surgeon must meticulously strategize the procedure and possess comprehensive knowledge regarding potential complications. Additional case studies, accompanied by protracted follow-up, will be requisite in the future to facilitate consensus formation on the optimal treatment for patients.