A 67-year-old male was admitted three times under various specialties over a span of eight months. He was pre-morbidly independent in Activities of Daily Living (ADL) and community ambulant without aids. Significant past medical history includes diabetes mellitus, hypertension, hyperlipidaemia and ischemic heart disease with heart failure with reduced ejection fracture. Others include prostate cancer status post cystoscopy, insertion of ureter guidewires and robot-assisted radical prostatectomy, and he remains in remission till date.
He was first admitted under General Medicine for a 4-month-history of unintentional loss of weight, borderline blood pressure, high white blood cell counts and functional decline since his prostate cancer resection surgery. Laboratory tests revealed serum white blood cell count of 21.39× 109/L, C-reactive protein level of 122.7 mg/L and procalcitonin level of 0.58 ug/L. A Computed Tomography scan of the Thorax, Abdomen and Pelvis (CT TAP) (Fig. 1) was done to find the source of infection which incidentally revealed a mild non-specific right hip effusion and a rheumatology review was obtained. X-rays appeared normal (Fig. 2). In view of no inflammatory symptoms, he was diagnosed to have right hip osteoarthritis and was discharged after two weeks hospitalization. At this time, no additional assessment or Orthopaedic referral was done to rule out the possibility of SA.
Over five months, he continued to functionally decline, being unable to tolerate prolong sitting and was mostly bedbound. He was re-admitted under Geriatric Medicine due to a fall secondary to lower limb weakness, right worse than left. Physical examination revealed right lower limb shortening, limited hip ranging with mild tenderness. X-rays revealed right hip destruction of the superior acetabulum with superior subluxation and left hip degenerative changes (Fig. 3). In view of significant progression of his condition, an Orthopaedic review was requested and Magnetic Resonance Imaging (MRI) of the pelvis and right hip showed evidence of moderate to severe bilateral hip effusion, worst on the right, with moderate joint effusion partially decompressing into periarticular soft tissues (Fig. 4). In addition, there was acute osteomyelitis of the right acetabulum and femoral head with bony destruction and subluxation and blood cultures grew pseudomonas aeruginosa. Ultrasound-guided right hip joint aspiration and core biopsy had no bacterial yield despite not having antibiotics started. Intravenous (IV) tazocin was started for pseudomonas bacteraemia coverage.
To ensure proper source control, the patient underwent bilateral arthrotomy, debridement, synovectomy and washout via an ABMS approach. Intra-operative cultures yielded pseudomonas aeruginosa and he received organism-specific IV ciprofloxacin daily for two weeks post-surgery, followed by oral ciprofloxacin for 6 more weeks. Post-operatively, his hip pain improved significantly but functionally, he remained bedbound requiring assistance for transfers.
Follow-up MRI 2 months post-operation revealed interval progression of SA worse over the left hip (Fig. 5). Inflammatory markers remained raised with serum white blood cell count of 15.7× 109/L and C-reactive protein level of 28.6 mg/L. Interval X-rays showed left hip progressive destruction while the right hip remained grossly stable since last discharge (Fig. 6). He was re-admitted for repeat bilateral hip joint washout, synovectomy debridement and a 1.5-stage antibiotic-loaded THA with CUMARS via ABMS approach, with both operations done in a single setting. An anterior-based approach was chosen to preserve soft tissue, muscle and reduce the risk of dislocation after THA. The surgery was performed under general anaesthesia in lateral decubitus position. The hip joint was fully exposed. Intra-operative right hip findings include recalcitrant SA and osteomyelitis with synovitis and no purulent fluid, false acetabulum with Paprosky 3A bone loss and subluxation more than 3cm. Meanwhile, intra-operative left hip findings include SA with synovitis with no purulent fluid, deformed and unhealthy femoral head, superolateral acetabular wall contained bone loss with superior wall intact. The damaged femoral head and neck were excised. Meticulous and radical debridement were performed to remove remnant infective tissues. The acetabulum was debrided using an acetabular reamer. Five tissues from each side were taken and sent for culture. The surgical site was then washed with iodine and saline. Prior to reconstruction, a surgical site was re-draped and surgical team re-gowned. A new set of surgical instruments was used for the reconstruction. The articulating spacers for the right hip were prepared using a Stryker Rimfit cup 50mm OD 32mm ID, Stryker LFIT V40 femoral head 32mm OD, + 4 offset and Exeter V40 cemented hip stem 35.5 offset stem length 125mm stem length. The articulating spacers for the left hip were prepared using a Stryker Rimfit cup 52mm OD 36mm ID, Stryker LFIT V40 femoral head 36mm OD, 0 offset and Exeter V40 cemented hip stem 35.5 offset stem length 125mm stem length (Stryker NY). The Palacos cement was loaded with 8g of ceftazidime total per hip. Due to the significant amount of acetabulum bone loss for the right hip, additional 2x3.5cm cancellous screw was inserted to the superior acetabular wall defect. At the end of each section of the surgery, first being wound debridement and joint washout with subsequent 1.5-stage THA, the hip was irrigated with copious amounts of normal saline, chlorhexidine subsequently soaked in 9mls of 10% iodine mixed with 250mls of normal saline.
Post-operatively, intra-operative cultures came back negative for bacterial growth, he completed 2 more weeks of oral ciprofloxacin and was allowed to full weight bear immediately. However, his rehabilitation recovery was slow requiring moderate to maximum assistance for ADLs due to sarcopenia from prolonged functional decline and bedrest. Post-operative X-rays done on day 0, 1-month and 1-year review revealed
On one-month review, he is able to ambulate with walking frame with minimum assistance. There was no clinical or biochemical evidence of recurrent infection with serum white blood cell count of 9.1 × 109/L, C-reactive protein level of 0.9 mg/L. On one-year review, he was he is able to ambulate with walking frame independently (Fig. 7) and there is no clinical evidence of infection recurrence. Overall, post-operative X-rays done on day 0, 1-month and 1-year review revealed stable bilateral hip replacement prostheses with no evidence of periprosthetic fractures or loosening (Fig. 8).