74-year-old woman with intraoperative acetabular fracture during THA
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The patient was a 74-year-old woman who presented to the office with chronic, worsening, right hip pain. Her past medical history included myasthenia gravis and dyslipidemia.
She previously underwent a total hip arthroplasty on the contralateral side to address her arthritic hip and was satisfied with her outcome. Radiographs obtained the day of the visit demonstrated severe right hip osteoarthritis (Figure 1). She had exhausted nonoperative management for her right hip and agreed to proceed with a THA.
A standard posterolateral approach to the hip was utilized. Following acetabular exposure and soft tissue releases, sequential acetabular reaming was performed. Under-reaming by 1 mm was done based on the manufacturer’s recommendation, and care was taken to avoid aggressive reaming and impaction given that the patient’s bone quality was noted to be poor intraoperatively. Once the final acetabular component was impacted, it was found to be loose. The acetabular component was removed, and a fracture of the posterior acetabular column was visualized.
Source: Yasir AlShehri, MD, and Bassam A. Masri, MD, FRCSC
At this stage, the decision was made to proceed with an open reduction and internal fixation (ORIF) of the fracture. Adequate visualization of the fracture needed to be obtained. The interval between the short external rotators and capsule was further developed to expose the posterior column. Further dissection was carried out superiorly along the posterior column to the greater sciatic notch, inferiorly to the lesser sciatic notch and to the upper portion of the body of the ischium. The sciatic nerve exiting the greater sciatic notch was protected by the short external rotators, and the capsule of the hip joint was reflected anteriorly. The hip was held in extension, and the knee in flexion to take the tension off the sciatic nerve. Finally, the hip abductors were partially retracted off the ilium with a cobra retractor to expose the entire fracture, which was noted to be minimally displaced, but had a transverse configuration into the anterior column.
Once the fracture was adequately exposed, we moved onto fixation. Ideally, a column-specific pre-bent acetabular plate would have been utilized but, unfortunately, none were available at the facility, as it was an elective arthroplasty center with no trauma being performed. The only available set was a small fragment set, from which a one-third tubular plate was used. The first plate used was a seven-hole plate, which was contoured to simulate the pre-bent column plate. The first two screws (one proximal and one distal to the fracture) were eccentrically inserted to allow for compression. Following that, remaining screw holes were filled apart from the most proximal hole. To increase stability, a five-hole one-third tubular plate was applied posterior to the first plate, which was contoured in a similar manner. The rationale for this was that a one-third tubular plate does not have the same strength as a dedicated acetabular reconstruction plate. With this technique, satisfactory fixation was obtained.
We then turned our attention to acetabular component impaction. An uncemented acetabular component was inserted with no screws due to the limited safe acetabular windows from the previously inserted screws, and a stable, satisfactory fit was obtained following impaction. The remainder of the procedure was uneventful, and the patient was made toe-touch weight-bearing for 6 weeks postoperatively (Figure 2). Immediate postoperative radiographs demonstrated satisfactory fixation and implant positioning with no femoral fractures. An undisplaced fracture involving the superior pubic root was also seen, thought to most likely represent anterior extension of the transverse acetabular fracture, but it did not require fixation.
The patient was seen in the clinic and examined at 2-week follow-up. Unfortunately, a few days prior to this clinic visit, she was standing at the kitchen sink and felt a snap in her right groin area. Since then, she had experienced increasing groin pain. Initially, the main concern was displacement of her acetabular fracture. However, radiographs revealed a new Vancouver B2 periprosthetic femur fracture (Figure 3). The acetabular fracture remained well aligned with no evidence of acetabular component loosening.
What are the best next steps in management of this patient?
See answer below.
Open reduction and internal fixation of the femur with femoral component revision
The patient was urgently booked for an ORIF in addition to femoral component revision. The previous posterolateral incision was utilized. Following exposure, the femoral component was found to be loose. It was easily removed without significant bone loss. The acetabular component was examined and found to be stable. Initially, two distal cerclage wires were inserted before reaming, one at the anticipated inferior end of the revision femoral component and one 2 cm to 3 cm distal to that to prevent propagation of the patient’s fracture. The medullary canal was sequentially reamed to accept a fluted tapered, diaphyseal-engaging revision femoral component (Redapt, Smith & Nephew). The fracture was then reduced and held with cerclage wires (Figure 4). The remainder of the procedure was performed in a standard manner. Toe-touch weight-bearing precautions were resumed for another 4 weeks postoperatively. The standard deep venous thrombosis protocol at our institution of using 162 mg aspirin daily was implemented.
The patient was seen in the office at 6 and 12 weeks postoperatively and was doing well. Her incision healed nicely, and she was fully weight-bearing without pain at 3 months postoperatively. Radiographs demonstrated union of her acetabular fracture with appropriate fixation of the acetabular and femoral components. She was referred to an endocrinologist for a comprehensive assessment for metabolic bone disease.
Discussion
Intraoperative acetabular fracture is a rare complication of THA but poses substantial challenges in terms of diagnosis, management and prevention. These fractures can occur during acetabular reaming or acetabular component impaction, and many risk factors can predispose patients to these fractures. R. M. D. Meek, MD, FRCS(Orth), found women older than 70 years had the highest risk secondary to poor bone quality. The location of the fracture has a significant influence on implant stability, and fractures involving the posterior column are more likely to result in an unstable acetabular component. Acetabular fractures may go initially unnoticed until the postoperative radiographs are reviewed.
When diagnosed intraoperatively, acetabular component stability must be assessed, and this factor usually dictates next steps. If the component is stable, it may be retained. If the component is unstable, stability must be obtained by ORIF of the acetabular fracture, and possibly supplementing the cup with screw fixation. Most of these fractures require internal fixation, as adding screws alone to an unstable acetabular component would be at high risk of early failure. Weight-bearing restrictions are usually introduced postoperatively.
In addition to the intraoperative management of acetabular fractures, it is crucial to consider the postoperative monitoring and the potential for subsequent complications, as evidenced in this case by the development of a periprosthetic femur fracture. Patients at risk for developing an intraoperative fracture typically have poor-quality bone, which predisposes them to further fractures, as was seen in this case.
This case also highlights the importance of having a comprehensive plan and the necessary equipment readily available to manage unexpected intraoperative situations, and being able to adapt and change the surgical plan if the required equipment is not readily available. A key learning point from this case is that, even though intraoperative acetabular fractures are rare, a small set containing six-hole right and left posterior column plates, plate benders, a long drill bit and a long-depth gauge should be available. This has since been implemented at our hospital. It is also important that arthroplasty surgeons be familiar with the technique of reducing these fractures and installing a posterior column plate. Finally, implementing a multidisciplinary approach involving endocrinologists, physical therapists, occupational therapists and additional specialists can optimize patient care, ensuring both immediate fracture management and long-term bone and general health.
Key points
- Poor bone quality is a significant concern in the older population undergoing arthroplasty, and many of these patients may have undiagnosed osteoporosis.
- Periprosthetic fractures may occur, and one must be ready to address these and adapt in cases where ideal fixation hardware is not present.
- Prompt referral to an endocrinologist or metabolic specialist is required to assess for metabolic bone disease and manage it accordingly.
- References:
- Benazzo F, et al. Int Orthop. 2015;doi:10.1007/s00264-015-2971-8.
- Brown JM, et al. Am J Orthop (Belle Mead NJ). 2017;46:232-237.
- Haidukewych GJ, et al. J Bone Joint Surg Am. 2006;doi:10.2106/JBJS.E.00890.
- Leflamme GY, et al. J Arthroplasty. 2015;doi:10.1016/j.arth.2014.09.013.
- Li J, et al. BMC Musculoskelet Disord. 2020;doi:10.1186/s12891-020-03356-5.
- Meek RM, et al. J Bone Joint Surg Br. 2011;doi:10.1302/0301-620X.93B1.25087.
- For more information:
- Yasir AlShehri, MD, and Bassam A. Masri, MD, FRCSC, can be reached at the department of orthopedics and faculty of medicine at The University of British Columbia and Diamond Health Care Centre in Vancouver, British Columbia.
- Edited by Nicole Rynecki, MD, and Harold I. Salmons, MD. Rynecki is a chief resident in orthopedic surgery at NYU Langone. She will be pursuing a sports medicine fellowship at Hospital for Special Surgery following residency completion. Salmons is a chief orthopedic surgery resident at the Mayo Clinic. He will be pursuing an adult reconstruction fellowship at Hospital for Special Surgery following residency completion. For more information on submitting Orthopedics Today Grand Rounds cases, please email orthopedics@healio.com.
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