Case of Bilateral Erosive Septic Hip Arthritis Following Pregnancy: a report

E.A. Boes et al report on a 34-year-old female whose normal spontaneous vaginal delivery was complicated by Group B streptococcus (GBS) colonization. She developed postpartum, bilateral, rapidly destructive septic hip arthritis. She was treated with bilateral articulating, antibiotic-impregnated spacers, 6 weeks of parenteral antibiotics, and subsequent conversion to total hip arthroplasties.

In pregnant women, GBS can result in bacteremia, urinary tract infection, endometritis, and pneumonia. Less commonly, GBS can lead to endocarditis, sacroiliitis, or septic arthritis. Septic arthritis of the hip following pregnancy has been described in a limited number of case reports, yet none, with rapid bilateral destruction requiring two-staged conversion to total hip replacement.

The patient is a 34-year-old healthy female who developed bilateral hip pain approximately 5 weeks following vaginal delivery. Her pregnancy course was complicated by GBS bacteriuria diagnosed on routine screening at 8-10 weeks gestation. She was treated with clindamycin for 5 days following diagnosis in the first trimester due to a penicillin allergy. Urine cultures subsequently revealed the GBS to be resistant to clindamycin. She then received vancomycin from the time of induction to delivery.

The patient had an induced vaginal delivery at 37 weeks due to hepatic cholestasis. She had an uncomplicated delivery without an episiotomy and no prolonged rupture of membranes (PROM). A first-degree laceration was repaired following the delivery.

Five weeks following her delivery, the patient developed progressive bilateral hip pain. She was initially evaluated by a sports medicine provider who noted significantly limited range of motion and weakness secondary to pain. Radiographs at that time were normal and notably without evidence of osteonecrosis, fracture, or degenerative changes.

A magnetic resonance imaging was obtained and demonstrated abnormal muscle signal and bony changes in the acetabulum and femoral neck suggestive of microtrabecular fracture or bone bruise. No significant joint effusions were identified. She was initially treated conservatively with symptomatic measures and physical therapy. Over the course of the next several weeks, the pain and stiffness progressed such that she became largely wheelchair bound. Two months later, she presented to the clinic and repeat radiographs showed bilateral erosive osteoarthritis with superior lateral head migration and acetabular and femoral head bone loss. Inflammatory markers were elevated with an erythrocyte sedimentation rate of 93 mm/hr and a C-reactive protein of 26 mg/dL.

Due to the severe pain and disability, along with the abnormal laboratory findings, the patient was then admitted to the hospital for pain control and further workup. Repeat bilateral hip magnetic resonance imagings revealed bilateral small hip joint effusions and significant synovitis. Aspiration of bilateral hip joints was attempted twice, both yielding dry taps even with fluid lavage. Blood cultures were negative. Rheumatology was consulted, and workup was negative for inflammatory arthritis. The infectious disease service was consulted and felt the diagnosis was most consistent with inflammatory arthritis.

Given the high suspicion for septic arthritis, the authors decided to proceed to surgery.On the right side, a standard posterior approach was performed with no purulence noted upon entry of the hip joint. The femoral head had extensive collapse and degeneration, and the acetabulum had significant superior-posterior bone loss. Intraoperative frozen section returned positive for chronic inflammation but negative for acute inflammation.

A DePuy (J&J Medical, Raynham, MA) Prostalac spacer was cemented in place with a total of three 40-gm batches of cobalt cement (Zimmer, Warsaw, IN). Each batch included 3 g of ceftazidime and 2 g of vancomycin.

On the left side, a mini posterior approach was used to perform open biopsy, cultures, and irrigation of the hip. No purulence was noted upon entry of the left hip joint. The patient's cultures grew GBS in multiple right hip cultures and MSSA in 1 left hip culture.

She was placed on intravenous cefazolin per the infectious disease consultant's recommendation. One week after her initial surgery, the patient then returned to the operating room for placement of an identical articulating spacer of her left hip. The patient was treated with 6 weeks of intravenous cefazolin. Inflammatory markers gradually normalized.

Nine weeks after her initial surgery, the patient underwent right stage 2 total hip arthroplasty via a posterior approach. The acetabulum had a significant superior-posterior defect necessitating the use of a trabecular metal augment (Zimmer, Warsaw, IN). An OsseoTi G7 acetabular component (Zimmer, Warsaw, IN) was inserted with good press fit and secured with multiple screws. The construct was unitized with cement. On the femoral side, a Wagner Cone Pros thesis Hip Stem (Zimmer, Warsaw, IN) was used.

She was discharged on doxycycline for 2 weeks per the infectious disease consultant's recommendations. Intraoperative cultures were subsequently finalized as negative. Four weeks later, the patient returned for stage 2 revision of her left total hip arthroplasty. On the acetabular side, a superior posterior largely cavitary defect was identified. An acetabular augment was not felt to be necessary on this side. Excellent press fit of the cup was obtained, and multiple screws were used to augment the fixation. She was discharged on Bactrim for 2 weeks per the infectious disease consultant's recommendation. Intraoperative cultures returned negative. The patient after 6 months from her first surgery has returned to household and community ambulation with the use of a cane for longer distances. She remains infection free at the time of reporting.

Further reading:

Bilateral Erosive Septic Hip Arthritis Following Pregnancy

E.A. Boes et al.

Arthroplasty Today 16 (2022) 192 - 196

https://doi.org/10.1016/j.artd.2022.05.008