Single-channel endoscopic minimally invasive technique for periarticular bone tumors: clinical application and technical analysis

Benign bone tumors arising in periarticular regions present substantial technical challenges for surgical management, primarily due to their proximity to articular surfaces and critical neurovascular structures, which constrain surgical access. In recent years, endoscopic curettage has been introduced as a tissue-preserving strategy[1]; however, most existing techniques rely on multi-portal or multi-channel approaches that require instrument triangulation. Such configurations are technically demanding within narrow intramedullary corridors, increasing procedural complexity and limiting reproducibility across different anatomical sites[2]. In contrast, single-channel endoscopy integrates visualization and instrumentation within a unified working channel, offering a potential solution for a simplified and site-consistent surgical workflow[3]. On this basis, we report our clinical experience using a standardized single-channel endoscopic curettage (SCEC) technique for selected periarticular benign bone tumors, with emphasis on technical feasibility, perioperative parameters, and early functional recovery. This study was conducted as a single-center, retrospective, single-arm technical case series. Between November 2021 and December 2024, consecutive patients with benign periarticular bone tumors underwent SCEC using a uniform procedural sequence[4]. Case selection was based on preoperative imaging and intraoperative assessment. Lesions were considered suitable when intralesional access could be achieved through a single cortical window without violation of the articular surface or the need for extensive soft-tissue exposure (Fig. 1). All procedures followed standardized core technical steps, including creation of a limited cortical window, endoscopic inspection of the cavity, stepwise intralesional curettage under direct visualization, and final cavity confirmation through the same working channel. To minimize variability associated with the learning curve, all procedures were performed by a consistent surgical team experienced in endoscopic techniques. Perioperative parameters and functional outcomes were collected retrospectively. Postoperative follow-up consisted of scheduled clinical review and imaging (X-ray, CT, or MRI), scheduled at 2 weeks, 1, 3, 6 months. Figure 1.: Representative case illustrating the standardized single-channel endoscopic curettage (SCEC) workflow for a benign lesion in the left femoral neck. (A–C) Preoperative assessment. (A) Anteroposterior pelvis radiograph. (B) Axial CT scan demonstrating the osteolytic lesion (red arrow). (C) Coronal and axial MRI sequences highlighting the lesion boundaries (red arrows), used to plan the safe corridor. (D–E) Intraoperative navigation and access. (D) Surgical setup with the O-arm imaging system. (E) Navigation interface verifying the establishment of a precise, single-channel trajectory into the lesion center. (F) Endoscopic curettage. Intraoperative endoscopic view showing lesion removal using a high-speed burr under direct visualization and continuous irrigation. (G–H) Postoperative verification. (G) Postoperative CT scan confirming complete tumor removal and dense filling of the cavity with graft material. (H) Follow-up MRI showing graft integration without evidence of local recurrence. Fifteen patients were included, with a mean age of 35.5 years. Tumors were located across multiple periarticular anatomical sites, including the hip, knee, humerus, tibia, ankle, and scapula. Pathological diagnoses comprised enchondroma (n = 6), simple bone cyst (n = 3), non-ossifying fibroma (n = 2), osteoblastoma (n = 2), and fibrous dysplasia (n = 2). Technical success was achieved in all cases, with no conversions to open surgery. The procedure was associated with a low operative burden. The mean incision length was 2.3 ± 0.6 cm, the mean operative time was 118.0 ± 21 minutes, and the mean intraoperative blood loss was 11.0 ± 5.2 mL. Postoperative recovery was generally uneventful. The mean length of hospital stay was 6.6 ± 2.1 days. Two minor complications (13.3%) were observed, including one transient sensory disturbance and one superficial infection, both resolved with conservative management. Functional outcomes improved significantly compared with baseline. At final follow-up, the mean MSTS score increased from 22.2 to 27.3, while the mean DASH score decreased from 41.5 to 11.8. During the available follow-up period (mean 8.7 months), no radiographic or clinical evidence of local recurrence was identified (Table 1). Nevertheless, we acknowledge that this follow-up duration is insufficient to evaluate long-term local control for biologically active lesions such as osteoblastoma, for which prolonged surveillance remains necessary[5]. Table 1 - Variable Value Demographics Age, years (mean ± SD) 35.5 ± 12.2 Sex (male/female) 7 (46.7%)/8 (53.3%) Duration of symptoms, months (median, range) 12.5 (1–60) Tumor characteristics Pathology, n (%) Enchondroma 6 (40.0%) Simple bone cyst 3 (20.0%) Non-ossifying fibroma 2 (13.3%) Osteoblastoma 2 (13.3%) Fibrous dysplasia 2 (13.3%) Location, n (%) Hip 4 (26.7%) Knee 3 (20.0%) Humerus 3 (20.0%) Tibia 2 (13.3%) Ankle 2 (13.3%) Scapula 1 (6.7%) Perioperative metrics (mean ± SD) Operative time (min) 118.0 ± 21.0 Intraoperative blood loss (mL) 11.0 ± 5.2 Incision length (cm) 2.3 ± 0.6 Length of hospital stay (days) 6.6 ± 2.1 Outcomes Complications, n (%) 2 (13.3%) Local recurrence, n (%) 0 (0%) Functional scores (mean ± SD) Preoperative vs. Final VAS (pain) score 4.8 ± 1.6 vs. 1.5 ± 0.8 (P<0.001) MSTS score (lower limb, n = 11) 22.2 ± 2.6 vs. 27.3 ± 1.1 (P<0.001) DASH score (upper limb, n = 4) 41.5 ± 4.5 vs. 11.8 ± 1.7 (P<0.001) This study demonstrates that a reliable and standardized single-channel endoscopic workflow is technically feasible and can be safely implemented across selected periarticular locations. By utilizing a single working channel, the technique preserves direct visualization of the cavity walls while substantially simplifying endoscopic setup. However, the limitations of this study, including its retrospective design, small sample size, and absence of a control group, must be acknowledged. Accordingly, these findings should be interpreted as preliminary feasibility data. Further prospective and comparative studies are required to define the long-term oncological outcomes and to clarify the clinical role of SCEC in the surgical management of periarticular benign bone tumors[6].