Reply to the comments on our article “Total hip arthroplasty for active tuberculosis of the hip”

Abstract

Dear Dr. Singh, We thank you for your letter and your interest in our article. Our response to your queries is as follows: We did not measure C-reactive protein (CRP) in our series. Although both erythrocyte sedimentation rate (ESR) and CRP could be used to detect the activation or reactivation of tuberculosis, ESR is preferred in most reports [1–3]. In most Chinese hospitals determination of ESR is a common practice in the diagnosis and treatment of tuberculosis while measurement of CRP is not. In our two patients with sinus, the sinus in patient 4 had healed when the patient was admitted into our hospital while the sinus in patient 6 was still discharging. We did not do a sinogram because it may cause iatrogenic mixed infection. Although many authors do not advise operating on patients with discharging sinus as it may result in incomplete debridement and higher rate of reactivation [1, 4, 5], so far there is no evidence that patients with sinus have a higher rate of reactivation after total hip arthroplasty (THA). Yoon et al. [1] chose resection arthroplasty with a two-stage operation, but they also think that a sinus tract into the pelvis or thigh may not constitute a contraindication to primary THA for tuberculosis of the hip. Since most discharging sinuses may be complicated by mixed infection which may increase the rate of postoperative periprosthetic infection, we recommend prolonging preoperative chemotherapy until the sinuses are healed and making sure that there is no mixed infection. In our patient 6, the antituberculosis medicine was administered for 54 days. The sinus healed and no mixed infection was detected before surgery. During the operation, we resected the sinus and used a long period of chemotherapy (18 months) postoperatively. There is no definite recommendation on the duration of antituberculosis medication before surgery. In most Chinese textbooks antituberculosis chemotherapy is recommended for at least two weeks preoperatively. Yoon et al. [6] also chose a limit of two weeks before surgery for active tuberculosis of the hip and Tuli [7] advises a minimum of one to four weeks of therapy before any major surgical intervention. In our series we chose two weeks as a basic limit and no reactivation of tuberculosis was detected within an average follow-up period of 49 months. Reports in the literature have stated that tuberculosis reactivation is not affected by the use of a cemented or cementless prosthesis. Authors can choose cemented or cementless arthroplasty according to the bone defect of the affected joint, experience of the surgeon and even the financial situation of the patients. In our study rifampicin and streptomycin were not used for local wash. These two powder drugs were put into the hip joint (around the prosthesis) just before the incision was closed. In a short time a high local concentration of antituberculosis drugs may help kill the residual bacteria and decrease the rate of reactivation. However, the benefit of local administration of antituberculosis drugs has not yet been proved. Some studies [1] without local administration of antituberculosis drugs seem able to achieve the same results as our study and further investigation is needed to elaborate whether it has added benefit. Immediate weight-bearing can be allowed in both cemented and cementless arthroplasty. Due to aches from the incision and the possibility of haemorrhage, most Chinese authors tell their patients to walk with crutches for one week after the operation, and full weight-bearing without crutches is allowed at least four weeks later even in patients with a standard arthroplasty. The last question has been answered in No. 2.