Can certain benign lesions of the proximal femur be treated without surgery?

Two Cannulated Screws Provide Sufficient Biomechanical Strength for Prophylactic Fixation in Adult Patients With an Aggressive Benign Femoral Neck Lesion

Background: Two cannulated screws were proposed for prophylactic fixation in adult patients with an aggressive benign femoral neck lesion in recent literature. However, the biomechanical properties of this intervention have not yet been investigated.

Methods: After the evaluation of the heterogeneity of bone mineral density and geometry via quantitative computed tomography, 24 embalmed adult human cadaver femurs were randomized into the control, inferior half of the anterior cortical (25%) bone defect, entire anterior cortical (50%) bone defect, and the 50% bone defect and two cannulated screw group. Biomechanical analysis was conducted to compare the stiffness and failure load among the four groups when mimicking a one-legged stance. A CT-based finite element analysis (FEA) was performed to mimic the cortical and cancellous bone defect and the implantation of two cannulated screws of the four groups. Measurements of the maximal displacement and von Mises stress were conducted with the longitudinal load force and boundary conditions being established for a one-leg-standing status.

Results: We noted a significant improvement in the failure load after the insertion of two 6.5 mm cannulated screws in femurs with 50% bone defect (+95%, p = 0.048), and no significant difference was found between the screw group and the intact femur. Similar trends were also found in the measurements of stiffness (+23%, p > 0.05) via biomechanical testing and the von Mises stresses (−71%, p = 0.043) by FEA when comparing the screw group and the 50% bone defect group.

Conclusion: Our findings suggest that two cannulated screws provided sufficient biomechanical strength for prophylactic fixation in adult patients with an aggressive benign femoral neck lesion even when the entire anterior cortical bone is involved.

Artificial intelligence-based classification of bone tumors in the proximal femur on plain radiographs: System development and validation

Purpose

Early detection and classification of bone tumors in the proximal femur is crucial for their successful treatment. This study aimed to develop an artificial intelligence (AI) model to classify bone tumors in the proximal femur on plain radiographs.

Methods

Standard anteroposterior hip radiographs were obtained from a single tertiary referral center. A total of 538 femoral images were set for the AI model training, including 94 with malignant, 120 with benign, and 324 without tumors. The image data were pre-processed to be optimized for training of the deep learning model. The state-of-the-art convolutional neural network (CNN) algorithms were applied to pre-processed images to perform three-label classification (benign, malignant, or no tumor) on each femur. The performance of the CNN model was verified using fivefold cross-validation and was compared against that of four human doctors.

Results

The area under the receiver operating characteristic (AUROC) of the best performing CNN model for the three-label classification was 0.953 (95% confidence interval, 0.926–0.980). The diagnostic accuracy of the model (0.853) was significantly higher than that of the four doctors (0.794) (P = 0.001) and also that of each doctor individually (0.811, 0.796, 0.757, and 0.814, respectively) (P<0.05). The mean sensitivity, specificity, precision, and F1 score of the CNN models were 0.822, 0.912, 0.829, and 0.822, respectively, whereas the mean values of four doctors were 0.751, 0.889, 0.762, and 0.797, respectively.

Conclusions

The AI-based model demonstrated high performance in classifying the presence of bone tumors in the proximal femur on plain radiographs. Our findings suggest that AI-based technology can potentially reduce the misdiagnosis of doctors who are not specialists in musculoskeletal oncology.

Patient-specific computed tomography-based finite element analysis: a new tool to assess fracture risk in benign bone lesions of the femur

BACKGROUND

Most benign active and latent lesions of proximal femur do not predispose a patient to a pathologic fracture. Nonetheless, there is a tendency to perform internal fixation due to the lack of accurate clinical tools that may reliably confirm low risk of pathologic fracture. As many as 30% of these surgeries may be unnecessary. A patient-specific CT-based finite element analysis may quantify bone strength and risk of fracture under normal weight-bearing conditions.

METHODS

The clinical relevance of such finite element analysis was investigated in a retrospective study on a cohort of 17 patients. Finite element analysis results (high risk = indication for surgery, low or moderate risk = follow-up) were compared to actual clinical decisions (surgery vs follow-up). All patients predicted by the finite element analysis as high risk underwent internal fixation and had good outcomes (n = 6).

FINDINGS

Four of the 11 low- and moderate-risk finite element analysis patients (36%) were operated immediately, and seven (64%) were either operated after a delay of at least 6 months or were never operated. None sustained a pathologic fracture. Patients who were predicted as low fracture risk by finite element analysis remained fracture-free for a minimal period of 6 months. Prediction of high risk of pathologic fracture by finite element analysis was in complete agreement with the conventional clinical evaluation.

INTERPRETATION

We consider finite element analysis a promising decision support system for the management of patients with benign tumors of femur, and that it may reliably endorse the decision to withhold surgery for patients at low fracture-risk.

[Treatment of proximal femoral benign lesions by proximal femoral nail anti-rotation combined with curettage and bone graft through the Watson-Jones approach]

Objective

To evaluate the feasibility and effectiveness of proximal femoral nail anti-rotation (PFNA) combined with curettage and bone graft through Watson-Jones approach in the treatment of proximal femur benign tumors and tumor like lesions.

Methods

The clinical data of 38 patients with benign tumors and tumor like lesions in the proximal femur who were treated through the Watson-Jones approach with PFNA combined with curettage and bone graft between January 2008 and January 2015 were retrospective analysed. There were 24 males and 14 females with an average age of 28 years (range, 15-57 years). Pathological types included 20 cases of fibrous dysplasia, 7 cases of bone cyst, 5 cases of aneurysmal bone cyst, 3 cases of giant cell tumor of bone, 2 cases of enchondroma, and 1 case of non-ossifying fibroma. Before operation, hip pain occurred in 19 patients, pathological fracture occurred in 12 patients, limb shortening and coxa varus deformity was found in 4 patients, and 3 patients received surgery for the local recurrence. The operation time, intraoperative blood loss, and full-weight bearing time after operation were recorded. Patients were followed up to observe union of bone graft and the position of internal fixator on X-ray films and CT images. Visual analogue scale (VAS) score was used to evaluate the level of pain. The Musculoskeletal Tumor Society (MSTS93) score was used to evaluate lower limb function. Harris hip score was used to evaluate hip joint function.

Results

The operation time was 130-280 minutes (mean, 182 minutes) and the intraoperative blood loss was 300-1 500 mL (mean, 764 mL). After operation, 3 cases of fat liquefaction of incision healed successfully by carefully dressing, and the rest incisions healed by first intention. All patients started partially weight-bearing exercise at 2-4 weeks after operation. The total weight-bearing time was 3-6 months (mean, 4.2 months). All the patients were followed up 24-108 months (median, 60 months). Imaging examination showed that the bone graft fused and the fusion time was 8-18 months (mean, 11.4 months). During the follow-up period, there was no complication such as pathological fracture, femoral head ischemic necrosis, hip joint dislocation, internal fixation loosening and fracture, and no tumor recurrence or distant metastasis occurred. At last follow-up, the VAS score, MSTS93 score, and Harris score were significantly improved when compared with preoperative ones ( P<0.05).

Conclusion

The treatment of proximal femoral benign lesions by PFNA combined with curettage and bone graft through the Watson-Jones approach is safe and effective, with advantages of better mechanical stability, less residual tumor, and less postoperative complications.

Surgical strategy for benign lesions in proximal femur: internal fixation or endoprosthetic replacement

PURPOSE

The purpose of this study was to explore the indications for the two most frequently applied surgical procedures for benign lesions in the proximal femur.

METHODS

We retrospectively reviewed 142 patients with benign lesions in the proximal femur from January 2010 to January 2015. Internal fixation (IF) was adopted in 110 patients, while endoprosthetic replacement (EPR) was applied in 32 patients. Clinical data, including operation time, blood loss, hospitalization time, and hospitalization expenses, were compared between the groups. Limb mobilization was evaluated by the Musculoskeletal Tumor Society Score-93 (MSTS-93) and Harris Hip Score (HHS). Local recurrences and complications were statistically compared.

RESULTS

The average follow-up was 66 months (range 32-84 months). In the EPR group, operation time and hospitalization time were significantly shorter (p < 0.05 and p < 0.05, respectively), while blood loss and hospitalization expenses were significantly higher (p < 0.05 and p < 0.05, respectively). Functional outcomes of the MSTS-93 and HHS were higher at the three week follow-up in the EPR group (p < 0.001 and p < 0.001, respectively) but lower at 6 months (p = 0.031 and p = 0.042, respectively). No differences were observed in the two scores at three  months (p = 0.261 and p = 0.134, respectively). Local recurrence and complication rates were similar in the two groups (p = 0.895 and p = 0.942, respectively).

CONCLUSION

The strategy for benign proximal femur lesions should depend on the site, size, initial diagnosis, and thinning degree of cortical bone. IF and EPR both result in satisfactory local control and functional and radiological results, while EPR is more suitable for aggressive and recurrent lesions and serves as an effective measure after IF failure.

[Treatment of benign bone lesions of proximal femur using dynamic hip screw and intralesional curettage via Watson-Jones approach]

Objective

To explore the effectiveness of dynamic hip screw (DHS) and intralesional curettage via Watson-Jones approach in treatment of benign bone lesions of the proximal femur.

Methods

Between March 2012 and December 2016, 20 patients (21 lesions) with benign bone tumors or tumor like conditions of proximal femurs were treated with DHS and intralesional curettage via Watson-Jones approach. Their average age was 27.8 years (range, 11-51 years), including 13 males and 7 females. The pathological diagnosis were fibrous dysplasia in 11 cases, simple bone cyst in 2 cases, aneurysmal bone cyst in 2 cases, benign fibrous histocytoma in 2 cases, giant cell tumor in 2 cases, and chondroblastoma in 1 case, including 3 pathological fractures. According to the Enneking staging system, 18 patients were in stage S1, 3 patients with pathological fractures in stage S2. There was no varus deformity or valgus deformity. The operation time, intraoperative blood loss, and time of full weight-bearing were recorded. X-ray film and CT were used to observe the bone graft fusion and location of DHS. Complications were recorded. Visual analogue scale (VAS) and Musculoskeletal Tumor Society (MSTS) scoring were used to evaluate function of lower limbs.

Results

The average operation time was 177.1 minutes (range, 110-265 minutes). The average intraoperative blood loss was 828.6 mL (range, 200-2 300 mL). There was superficial incision infection in 1 case, deep incision infection in 1 case, and hip discomfort in 1 case, respectively. All patients were followed up 6-63 months (mean, 27.4 months). The time of full weight-bearing was 2 days in 2 patients with giant cell tumor and 2 to 13 weeks with an average of 7.2 weeks in the other patients. At last follow-up, VAS and MSTS were 0.19±0.51 and 29.62±0.97 respectively, showing significant differences when compared with the values before operation (3.52±2.62 and 23.71±8.77) ( t=5.565, P=0.000; t=-3.020, P=0.007 ). X-ray film showed the all bone grafts fusion with mean time of 8.2 months (range, 5-12 months). There was no pathological fracture of the femur, local tumor recurrence, chronic hip pain, dislocation, or femoral head necrosis during follow-up.

Conclusion

The treatment of benign bone lesion of the proximal femur using DHS and intralesional curettage via Watson-Jones approach is a safe and effective method.