Abstract
Osteogenesis Imperfecta is an inherited disease characterized by easily-broken bones, which manifests as multiple fractures with minimal trauma, joint laxity, sclerosis, blue sclera, and several other manifestations. Protrusio acetabuli is defined as the displacement of the femoral head so that it lies medial to the ischioilial line. In a skeletally mature patient with both Marfan syndrome and PA, an eventual hip arthroplasty is the only method available for correction of the deformity. However, in patients with Osteogenesis Imperfecta and PA, THA remains a controversial treatment.
A 14-year-old male patient diagnosed with Osteogenesis Imperfecta Type 1A presented to the orthopedic surgery clinic complaining of groin pain of 1-year duration radiating to the thigh and knee. The patient was found to have radiologic signs of protrusion acetabuli. The patient was started with bisphosphonate and after medical failure, underwent a Total Hip Arthroplasty (THA). In post-operative follow-ups, the patient had relief of pain and was able to walk more comfortably and without a lump.
The previously operated hip was examined and showed no signs of infection, dislocation, or fracture. Radiographic studies show no evidence of prosthesis failure or loosening with valgus position of the femoral stem and neutral acetabular angle. Ten years after the primary arthroplasty, the previously operated hip had maintained its stability and had no related complications.
Despite the controversy surrounding the treatment of younger patients with hip failure, using total hip arthroplasty, this patient exhibited excellent results, with vast improvement in their symptoms and stability.
1. Introduction
Osteogenesis Imperfecta (OI) is a heterogeneous group of connective tissue disorders which are inherited in nature. The most common genetic mutations associated with OI are those of COL1A1 and COL1A2. It is usually inherited as an autosomal dominant disease and, less commonly, in an autosomal recessive inheritance.
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The major consequence of OI is increased bone fragility, leading to a higher rate of fractures in affected individuals. Other manifestations include blue sclera, brittle teeth, pectus excavatum/carinatum, or hearing loss.In 1977, the Sillence Classification for OI was introduced and separated the types of OI based on the mode of inheritance and the presence or absence of certain symptoms.
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The most common type of OI is Type 1A, which is also the mildest type. Diagnosis of OI is done by taking a detailed family and medical history, performing a detailed physical examination, and typically X-ray imaging.Other genetic collagen disorders include Marfan syndrome and Ehlers-Danlos syndrome. There is an overlap of symptoms between these three disorders. To diagnose a patient with Marfan syndrome, the individual must fit the criteria as defined by the revised Ghent nosology.
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If a patient does not fit these criteria but has features commonly found in Marfan syndrome, this is known as Marfanoid habitus. The features of Marfanoid habitus commonly include long limbs, a crowded oral maxilla, a high-arched palate, hyperlaxity, arachnodactyly, as well as Protrusio Acetabuli (PA).5
PA can be defined as a protuberance of the femoral head medial to the ilioischial line. On radiographs, measurements aiding in the diagnosis of PA are the center-edge angle and the side of the acetabular fossa. A center-edge angle greater than 40°, and an acetabular fossa larger than 3mm in men and 6mm in women are criteria for diagnosis. In the following case report, we discuss the case of an Osteogenesis Imperfecta patient who underwent Total Hip Arthroplasty for the treatment of PA, 10 years after the procedure, and whether or not it can be considered an appropriate treatment.
2. Case report
2.1 Case presentation
A 14-year-old male previously clinically diagnosed with Type 1A Osteogenesis Imperfecta presented to the orthopedics clinic complaining of right groin pain of 1 year duration, which radiates to the thigh and knee. The patient complained of a constant limp while walking.
On physical examination, the patient was found to have bluish discoloration of the sclera, pectus excavatum, a high-arched palate, left cubitus varus, a positive Walker-Murdoch and Walker sign, positive Thomas test, shortened right forearm, genu recurvatum, joint hypermobility, valgus heels, medial displacement of the medial malleolus, and pelvic obliquity. The patient was also found to have a significantly decreased range of movement in his right hip, with flexion reaching 80°, abduction reaching 40°, adduction reaching 30°, internal rotation of 5°, and external rotation of 10°.
Radiographic imaging showed Tonnis grade 3 right hip osteoarthritis. The right femoral head was shown to be medially displaced. The patient was subsequently diagnosed with PA.
Over the following year, the patient had also suffered a right ulnar fracture, a left supracondylar fracture, and a left olecranon fracture following minor trauma.
The patient was started with bisphosphonate therapy in conjunction with conservative management in preparation for later surgical intervention. He received 4 doses of Zoledronic acid therapy over 9 months, which did not improve his symptoms. The right ulnar and left supracondylar fracture were treated with casting, while the left olecranon fracture was treated with Open Reduction Internal Fixation surgery.
Regarding his PA diagnosis, the patient was presented with two surgical options to reduce pain and improve hip motion; Hip Arthrodesis and Total Hip Arthroplasty (THA). After discussing the risks and benefits of both options, the patient and their family elected to proceed with THA.
An Anterolateral approach was used to access the hip joint, which demonstrated significant arthritic changes with a large area of cartilage loss consistent with the diagnosis. Bone autograft taken from the extracted femur head was used to fill the acetabular defect. A Muller acetabular roof reinforcement ring 48mm (Zimmer) was placed and fixed by two 6mm bone screws.
After insertion of bone cement, a 47 mm acetabular cup I.D. with a 10-degree-inclined face was placed. Later, a 115 mm stem length femoral component was press fit successfully, and was fitted with a standard neck with a +3.5 lateral offset and a 28-mm femoral head. There was a stable fracture of the greater trochanter intraoperatively during trial reduction. Total blood loss intraoperatively was 400 mL.
The patient was allowed to undergo protective weight-bearing as tolerated 1 day postoperatively, and the postoperative period was uneventful other than receiving 2 units of packed RBCs 2 days post operation for low hemoglobin level.
Six months after the THA, the patient has sustained a fall and suffered a fracture of the pubic symphysis which was treated conservatively.
The patient visited the clinics every 6 months after the procedure and underwent radiographic imaging annually. The previously operated hip had shown no signs of infection, dislocation, or fracture. The patient did not complain of pain and no longer walked with a limp. Radiographic studies showed no evidence of prosthesis failure or loosening with valgus position of the femoral stem and neutral acetabular angle.
The patient went on to graduate from school, work multiple jobs, and obtain a university degree in accounting.
3. Discussion
Osteogenesis Imperfecta is a life-long, complex disease. OI can be associated with an array of symptoms that are not part of the typical clinical presentation. As a hereditary collagen disorder, it can overlap with other disorders, such as Marfan syndrome or Ehler-Danlos syndrome. OI can present with several musculoskeletal abnormalities which could widen the array of differential diagnoses. In this case, where the patient presents with a clinical picture similar to Marfan syndrome, it is important to rule out accompanying cardiovascular abnormalities, such as aortic root dilation and mitral valve prolapse, using echocardiography.
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The first step towards treating OI is correctly identifying and classifying it, therefore taking into account its long-term consequences. In patients with OI Type 1A, the top priority of the physician is to maintain the bone to the greatest extent possible. This treatment usually initiates with drugs which aim to reduce the fracture rate, such as bisphosphonates, monoclonal RANKL antibody, and recombinant parathyroid hormone. These drugs are not necessarily effective. They are given along with vitamin supplementation.
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In the case of fractures and deformities, surgical intervention is needed. Successful treatment allows the patient to be able to carry on a relatively normal life. However, surgical treatment can be challenging in these patients, due to skeletal deformity and low bone mineral density.
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This can lead to varying success rates and controversy over the accepted methods of surgical treatment. Literature describing the surgical treatment of Protrusio Acetabuli in patients with Osteogenesis Imperfecta is few and far between. The use of total hip arthroplasty in such patients is even less documented.4. Conclusion
This study has shown that THA may be an effective treatment for Protrusio Acetabuli in patients with OI Type 1A. Use of THA in these patients may be an effective way to reduce pain and improve function in the affected hips.
5. Submission declaration
The work described has not been published previously and it is not under consideration for publication elsewhere. This publication is approved by all authors and if this manuscript is accepted, it will not be published elsewhere in the same form, in English or in any other language, including electronically without the written consent of the copyright holder.
Declarations of interest
None.
Appendix A. Supplementary data
The following is the Supplementary data to this article:
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References
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- The revised Ghent nosology for the Marfan syndrome.J Med Genet. 2010; 47: 476-485
- Marfan syndrome: an update of genetics, medical and surgical management.Heart. 2007; 93: 755-760
- Protrusio Acetabuli. Hosp Joint Dis. 2005; 62: 3-4
- Marfan's syndrome and the heart.Arch Dis Child. 2007; 92: 351-356
- Treatment of osteogenesis imperfecta in adults.Eur J Endocrinol. 2014; 171: R79-R90
- Challenges of fracture management for adults with osteogenesis imperfecta.Orthopedics. 2017; 40: 17-22
Article info
Publication history
Published online: May 27, 2019
Accepted:
May 21,
2019
Received in revised form:
February 7,
2019
Received:
October 19,
2018
Identification
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