HIV infection leads to a reduction of CD4 T-cell counts, dysfunction of the macrophages and monocytes, and thus finally leads to immunodeficiency, which is prone to various opportunistic infections and tumors. Highly Active Antiretroviral Therapy (HAART) can inhibit virus replication, improve the immunity of patients, prolong the survival time of patients, and greatly improve the quality of life of patients [15–16].The related complications have gradually attracted people's attention, among which the research on bone tumor, osteoporosis and brittle fracture has gradually become a hot topic in recent years [17–18].
Given that increased inflammation, T-cell activation, and monocyte activation contribute to the pathogenesis of many HIV-related comorbidities . We hypothesized that the pathological fracture of HIV with GCT may be related to the decreased immunity of the normal host, long-term chronic inflammatory stimulation, T cell activation and abnormal activation of mononuclear macrophages. GCT is a kind of osteolytic tumor, mononuclear cells and osteoclasts multiple nuclear cells as the main component. Chronic inflammation is a well-established risk factor for bone loss. Bone resorption occurs through osteoclasts, highly specialized cells formed from the fusion of the origin of monocyte/macrophage cells [20–21]. In inflammatory conditions, RANKL is also expressed by activated T cells and B-cells, resulting in increased osteoclast activity and bone loss, which may lead to pathological fractures.
GCT are characterized by invasiveness, relapse, and pathological fracture. Since GCT is mostly located at the bone end and has the imaging characteristics of osteolytic destruction, eccentricity and expansion, it is not difficult to diagnose GCT with pathological fractures for the most part . GCT of the long bone are relatively low in invasiveness. If the tumor size is small and the bone damage is light, the lesions can be simply scraped and transplanted without fixation to achieve stability. However, if the lesion range is wide, the bone cortex becomes thin due to severe erosion, and the biomechanical strength is reduced or even pathological fracture is complicated, it is particularly important to choose the appropriate method to fix the fracture.
In the early stage, benign bone tumors were mostly treated with external fixation stents . With the development of internal fixators, intramedullary nails and steel plates are used more and more frequently. Intramedullary nails belong to axial fixation, and multi-center studies have found that the effect of intramedullary fixation is better . At present, the miniature locking bone plate makes the fixation system more perfect as it has good fit, strong plasticity and easy anatomical fixation, does not take up excess space, and stabilizes the fracture end to promote fracture healing. In this group of cases, the miniature locking bone plate was used to bridge the lesion bone defect area to provide sufficient fixation strength and promote the normal healing of fractures. There was no loosening or displacement of internal fixator, and it was relatively easy to operate the technology of bridging locking plate on both sides of the fracture end after the removal of the lesion and bone grafting.
Most benign bone tumors had good prognosis and low recurrence rate after bone grafting. Reducing postoperative recurrence is one of the most concerned problems in the clinical treatment of benign bone tumors . At present, many scholars try to use adjuvant therapy, such as carbonic acid, liquid nitrogen, bone cement treatment in order to reduce the recurrence rate, but did not find that adjuvant therapy can effectively reduce the local recurrence rate. Blackley et al.  reported that 59 cases of GCT were treated with high-speed grinding drill assisted curettage, with an average follow-up of 80 months and a recurrence rate of 12%. The postoperative recurrence rate of patients in our study was low, which may be related to the routine use of Ultrasonic scalpel during the operation. Ultrasonic scalpel can reduce the difficulty of surgery, shorten the operation time, remove the bone crest tumor cells that cannot be scraped by conventional curettles, achieve the effect of edge resection, and ensure the thoroughness of surgery. Cutting and tumor tissue damage effect more ideal, make the surgery more safe and cutting temperature is low, is 70 ℃ ~ 80 ℃, to destroy the cancer cells, further reduce the recurrence of the tumor.
All patients received highly effective retrovirus drug therapy, and the viral load control was not ideal, with an average of 87323 copies /ml. Although no tumor recurrence or distant metastasis occurred in all patients, 4 patients of 14 had surgical site infection, with an incidence rate of 28.5%, which may be related to low immunity and HIV-RNA viremia. It has been confirmed that T-lymphocyte-mediated cellular immunity plays a major role in tumor immunity. The T lymphocyte subsets of normal body coordinate with each other and play an effective role in cellular immunity. The results of this study showed that the T lymphocytes of HIV-positive patients with GCT decreased as a whole and the CD4+ / CD8 + ratio decreased, suggesting that the immune function of the body was further impaired, creating conditions for surgical site infection .
The MSTS93 score system was used to evaluate the postoperative score improvement of each patient. The MSTS93 score of the patients 6 months after the operation was 24–27 points (24.5 ± 1.08), with a significant difference (P < 0.05), which indicated that all patients were satisfied with the short-term postoperative effect.
This study also has some limitations:(1) the sample size was not enough and the follow-up time was short, so the clinical curative effect remains to be studied further; (2)MSTS93 scoring system can provide an evaluation scale for patients after limb surgery, but this system is affected by subjective factors, including patient cooperation degree, patient cognitive ability, and physician clinical experience, and cannot achieve objective evaluation. But long-term efficacy remains to be seen.