We conducted a single-center, retrospective cohort study of patients treated with THA for SA of the hip. From January 2014 to December 2017, 21 patients with SA of the hip were eligible for enrolment in our study. Among them, 1 patient decided to leave the hospital and was treated in the local hospital after being diagnosed. A total of 20 patients were finally included. Inclusion criteria were patients who 1) were aged ≥ 18 years; 2) had a definite diagnosis of acute SA of the hip joint; 3) were advanced SA with destruction of hip joint; and 4) had a set of complete medical records (including nursing records), preoperative and postoperative radiographs. Exclusion criteria were patients who 1) were early SA of hip; 2) were multiple arthritis; 3) had incomplete medical records; 4) were not willing to be followed up, 5) had immune deficiency.
Patients with SA of the hip had clinical symptoms of infection including pain, sudden chills and fever; local swelling, and limited range of motion. In addition, complete blood cell count (CBC), C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) were measured. X-ray, CT and MRI were also performed. X-ray showed narrowing of the hip joint space for advanced SA of the hip. CT could detect local edema, osteonecrosis, osteomyelitis, and hip bone destruction. MRI provided good resolution for the detection of joint effusion, bone differentiation, and soft tissue infection. MRI findings of SA patients include joint effusion, cartilage and bone destruction, soft tissue abscess and bone edema  (Figure 1-3). The diagnosis of SA synthesized the results of these tests. If the patient was suspected of having septic arthritis, PPD test, Brucella agglutination test and needle aspiration of the hip were then added. The pre-operative samples of 6 cases were positive, including Staphylococcus aureus in 3 cases, Brucella in 1 case, Mycobacterium tuberculosis in 1 case, and Klebsiella pneumoniae in 1 case. The advantages and disadvantages of two-stage THA were addressed for the specific patient, and then developed a surgical plan according to patent’s willing .
All of the 20 patients (20 hips) underwent two-stage surgery. Nine patients were submitted to surgical debridement first, and then THA (group 1), while 11 patients were treated with antibiotic-loaded spacer and subsequent THA (group 2). Patients chose one of two procedures according to patent’s willing. All operations were performed by four professional surgeons in our department.
During the first stage, posterolateral approach was performed in all patients. Debridement was performed in group 1 and femoral head resection with antibiotic-loaded spacer implantation were performed in group 2. The inflamed soft tissues, necrotic bones, abscesses, and sinus tracts were totally debrided during the first stage. Then the 4-5 samples were taken from different parts of the suspicious joint for pathological examination and bacterial culture. For patients undergoing debridement, irrigation tube were placed in operation and continued to be rinsed with gentamicin solution after operation. For patients undergoing femoral head resection and antibiotic-loaded spacer implantation, femoral head were removed and a cement spacer containing gentamicin were installed (Figure 1). Until the patient’s symptoms disappeared and the serum became negative, the patient was allowed to be discharged, and was required to take oral antibiotics at least two weeks [11,10]. CBC, CRP and ESR were detected for weekly regular monitoring. In general, patient was conducted for traction of the affected limb if the pain (VAS score of 4-6) affected sleep after operation. After surgery for 48 hours, patient strengthened functional exercise [10,12].
During the second-stage, all procedures were performed via the posterolateral approach, with the patient in a lateral position.When the joint was opened, no pus and no inflammatory edema of soft tissue around the joint was confirmed under the naked eye. Then the hypertrophic soft tissue and scar was removed as thoroughly as possible in the direct visualization. Odophor and hydrogen peroxide were used ito immerse the hip joint cavity to reduce the probability of infection. Acetabular impactors were used to perform impaction grafting. Then Titanium Acetabular Reconstruction Cup was used for 2 cases with deficient acetabular wall, which was fixed with screws. The gap between cup and host bone was completely filled by allogeneic morselized bone. On completion of cage placement and bone grafts, an acetabular polyethylene liner was fixed with high radiopaque bone cement conting gentamicin. In addition, central acetabular defect in 3 patients were performed impaction grafting using acetabular impactors, and a larger acetabular cup was implanted. Besides, 1 patient had a high hip dislocation secondary to SA of the hip. Structural autograft obtained from the femoral neck was implanted on the patien’s upper acetabular bone and fixed with screws. The remaining 14 patients were were installed with matching acetabular cup after grinding of the acetabulum. The usage of antibiotics dependeded on the susceptibility of the first-stage organism identified in joint fluid culture. Antibiotics were chosen empirically if no organism was identified.
The scanning edition of electronic medical records were reviewed in detail to retrieve pertinent information, including demographic data (gender, age, height and weight), the preoperative and postoperative clinical evaluation (CBC, CRP and ESR), imaging evaluation (X-ray, CT and MRI), Harris hip score and VAS pain score. Clinical data were all recorded during follow-up.
Anteroposterior and lateral radiographs of the hip, full-length view of the lower extremities, CT and MRI of the hip were taken for the pre-operation. In our department, patients were required to have regular follow-up in the 1st month, the 3rd month, the 6th month and the 12th month after operation. Anteroposterior and lateral radiographs of the hip were taken at each follow-up. All of the 20 patients had adequate preoperative and postoperative imaging examinations.
All data were performed using SPSS 19.0 software (IBM, Armonk, NY, USA). Quantitative data were described using means ± standard deviation (SD). Mann-Whitney U test was used to compare continuous categorical variables, including Harris hip score and VAS pain score between the two groups. A P value of less than 0.05 were considered statistically significant.