Since Heijden12 and other scholars suggested treating GCTB with curettage, burring and adjuvant therapy in 2014, the local recurrence rates have decreased from 30%-50%12,13 to 6%-25%14,15. However, due to the use of numerous methods of inactivation, the clinical effects vary. Therefore, we proposed a systematic and efficient intraoperative management protocol for GCTB Companacci II and III based on the literature and our own experience. According to the results, the overall operating time for TC was significantly shorter than that for SR with prosthesis reconstruction, which resulted in a lower rate of intraoperative bleeding and a greater benefit to patients. A recurrence rate of 7.3% was achieved after TC, which is the lowest recurrence rate reported over the past decade7–9,16−20. However, Fraquet21 believed that segmental resection was the best choice for GCTB, including GCTB graded Companacci III, GCTB located at the distal radius, ulna, fibula and other non-load-bearing sites. The reason was that GCTB graded Companacci III is characterized by a large area of bone destruction and is bound to the articular surface, in some cases destroying the articular surface. However, after the improvement of the intraoperative process, we hypothesized that TC would also be suitable for GCTB graded Companacci III. According to the statistical results, we found that the recurrence rates after the two operations were similar, indicating that the effect of tumour cell elimination achieved by TC was similar to that achieved by SR. TC was even used in two patients whose lesions were located at the proximal humerus, and there was no recurrence observed in these two patients. Moreover, the patients maintained good upper limb function, which could not be achieved with SR. Some researchers believe that GCTB with pathological fracture is more likely to recur after surgery and, thus, SR should be chosen to reduce the recurrence rate. Our results indicated that even for patients with pathological fracture, the recurrence rates after SR and TC were similar. Moreover, TC could avoid the loss of autogenous articular tissue in young patients. Therefore, the acceptability of TC is obviously better than that of SR. In addition, patients in the TC group had more options for the second operation after recurrence, including a second curettage or SR. However, for patients in the SR group, amputation was likely the only remaining life-saving option. The choice of SR as the preferred treatment obviously deprives patients of the opportunity for limb preservation. However, for lesions with a wide range of joint damage, the joint surface is likely to collapse after the removal of tumour tissues, which will lead to leakage of articular fluid and a series of complications. Under these circumstances, TC is not applicable, and SR should be the preferred option.
In the procedure of TC, there were three key steps, as follows. 1) Scrape-out: Researchers generally agreed that a thorough curettage is the first and most important step. High-speed burring (HSB) has become a method highly praised by clinicians22. The required thickness of burring in different positions has been reported (approximately 1 mm into the normal cortical bone and 5 mm into the normal cancellous or subchondral bone23). However, in practice, it is difficult for to evaluate the thickness. Some researchers hypothesized that the sputtering of particles would cause the dissemination of tumour cells during HSB24. However, we do not think that the use of HSB will significantly reduce the recurrence rate in comparison with using curettes based on the fact that the scraping procedure used for TC is very careful and thorough. The tumour tissues could be easily removed by a large curette, and the wall of the residual cavity was scraped. The wall is not smooth; it contains many crests. After extensive burring with a large curette, medium and small curettes were used to subtly scrap the depressions. The whole process lasted at least 30 min. A dental endoscope was used to check the wall and ensure that there was no residual tumour tissue. This is a very efficient innovation. All of the researchers agreed that the window that made to expose the lesion completely should be as large as possible. However, occasionally, the size of the lesion could not be accurately evaluated only by imaging and the extent of the residual cavity after scraping was much larger than that of the window. As a result, there were many blind areas that made it impossible to achieve complete scraping. Therefore, we chose to use a dental endoscope to solve this problem. The use of the endoscope allowed us to be sure that any operation we performed in the residual cavity was complete. 2.) Flushing out: A flushing gun was used to flush the residual cavity several times during the operation. The first wash was to wash off and remove the loose tissues on the surface of the scraped wall. The second wash was to dilute the remaining anhydrous ethanol in the residual cavity, which avoided the combustion of AE during electrocauterization and further removed tumour tissues. The third irrigation was to remove the carbonized tissues and reduce the subsequent inflammatory response after electrocauterization. The frequency of each irrigation depended on the different conditions. 3.) Burn out: For adjuvant therapy, two of the safest methods (AE and electrocauterization) were used. We believe the effect of AE infusion is superior to smearing AE. However, its applicability depends on whether infusion can be applied. Infusion the residual cavities with articular surface defects or pathological fractures is not recommended. Infusion is also not applicable to invaded soft tissues. The leakage of AE to the peripheral and intra-articular spaces is likely to cause injury to the vessels and nerves along with other complications. The Electromes in the electrocoagulation mode were used for cauterization at a power of 60 W. The temperature was estimated to reach a range of 150 ℃ to 200 ℃. This temperature is far beyond the minimum temperature (50℃25) that can cause the necrosis of tissues. After AE infusion and cauterization, We believe that the combination of AE infusion and cauterization achieves deeper inactivation than AE or electrocauterization alone. Thus, with this method, the tumour tissues can be eliminated more thoroughly. The process was also applicable to invaded soft tissues. However, it is noted that for the wall close to the articular surface, the cauterization time should be reduced appropriately. Because the cortex of the articular surface is thin, extra-high temperatures and long heating times are likely to cause damage to chondrocytes. This damage is often irreversible, which will lead to serious joint complications.
For implant materials, we used to choose bone cement. The results of many previous studies indicated that the polymerization heat from bone cement could further inactivate tumour cells and further reduce the recurrence rate26. Moreover, bone cement also provides good mechanical strength after surgery. However, according to the statistical results, we found that there was no significant difference in the recurrence rate between the BC group and the BG group, which might be because the polymerization heat effect of BC after high-temperature inactivation by electrocoagulation was negligible. We also compared the functional recovery between the two groups and found that the functional recovery was not affected by the implant. In the BG group, no fracture was found during routine functional exercise after surgery, indicating that bone grafting could also fully support the patients' postoperative functional rehabilitation after strong internal fixation. However, in the BC group, we found that some patients had discomfort around the joint. Considering that bone cement may cause long-term complications such as osteoarthritis, allogeneic bone grafts have been increasingly chosen as the filling material. During the follow-up, we observed an obvious bone repair response in the residual cavity after bone grafts (Fig. 2F). This self-repair and spontaneous fusion will lead to greater comfort and better functional recovery in the long term. Later, with the exploration and application of biomaterials, bone grafts with osteoinductive biomaterials may be a better choice for clinicians.
For the follow-up of limb function, two time points (3 months and 2 years after surgery) were selected. Three months after surgery is a transitional time point for the recovery of limb function, while two years is a stable point. At the two time points, we found that the limb function of patients in the TC group was superior to that of patients in the SR group. In addition, the rehabilitation training for patients in the TC group was much easier, and the recovery period was shorter, which indicated that the retention of autologous joints had a beneficial influence on postoperative functional recovery. On the premise of the analogously low recurrence rates of the two surgical methods, the degree of satisfaction in patients in the TC group was higher than that in patients in the SR group. Since patients with GCTB are mostly young and middle aged, long-term complications caused by artificial joints can be expected. During the follow-up, 3 of 19 patients underwent revision surgeries. The high possibility of revision surgery after SR is another financial and emotional burden for patients. At present, except for superficial infection in one patient, we have not found any operation-related complications in the TC group, which may be due to the insufficient follow-up period. More patients and longer follow-up periods are needed to completely analyze the pros and cons of TC.
In both the SR and TC groups, one patient experienced relapse and died due to multiple metastases. At least two rigorous pathological examinations were performed on both patients, and the results were consistent. The rate of metastasis of GCTB is 1.5%. The cellular and molecular biological aspects of this potential invasiveness are unknown. Therefore, we can only assess the state of tumour cells indirectly through patient characteristics. In the management of patients with GCTB, personal characteristics may also influence the choice of surgery. We emphasize the importance of repetitive pathological examinations. The aim of repetitive pathological examinations is not only to further confirm the diagnosis but also to detect changes in the course of the disease. The malignant transformation of GCTB is common. Once malignant transformation occurs, curettage within the lesion is absolutely not recommended, as it will lead to the artificial spread and metastasis of tumour cells. Disease progression caused by the wrong surgical choice can be catastrophic and even fatal; thus, follow-up is a critical aspect of patient management. If large recurrent lesions appear in a short period and progress rapidly, the possibility of malignant transformation should be considered first. Under these circumstances, SR should be chosen as the treatment option to avoid the worst outcome, even if the images still show the characteristics of benign tumours.