Limited Revision with a Newly Designed Hinge Device for the Treatment of Mega-Prosthesis Hinge Failure: Two Case Reports.

BACKGROUND: Surgical treatment for hinge failure in mega-prosthesis continues to be a challenge. This study introduces a new method for treating hinge failure by using a unilateral prosthesis and hinge revision. CASE PRESENTATION: We here present two patients who underwent mega-prosthesis reconstruction after resection of osteosarcoma in the distal femur. To address the issue of knee hyperextension after mega-prosthesis reconstruction, one patient underwent three revision surgeries, two surgeries were performed using the original hinge, and one surgery involved a newly designed hinge. To resolve the problem of dislocation, one patient underwent three revisions, with the first two revisions not involving hinge replacement and the third revision involving a newly designed hinge. Two replacements of unilateral prosthesis and hinge renovations were successful. CONCLUSIONS: Unilateral prosthesis and newly designed hinge device revision are effective in treating the failure of old-fashioned mega-prosthesis hinges.

Case report: Sintilimab combined with anlotinib as neoadjuvant chemotherapy for metastatic bone tumor resection in patients with PSC.

Background: Pulmonary sarcomatoid carcinoma (PSC) is a rare subtype of non-small-cell lung cancer (NSCLC), which is resistant to chemotherapy and radiotherapy with a poor prognosis. PSC is highly malignant and is prone to recurrence even after surgery. The programmed death-ligand 1 (PD-L1) tumor cell proportion score (TPS) 5%, TERT and TP53 gene mutations were detected in this patient accompanied by multiple metastatic sites. The anlotinib is a novel multitarget tyrosine kinase inhibitor (TKI) that could be effective for advanced NSCLC and some sarcoma patients. Limited clinical trials and case reports have shown that PSC patients with gene mutations and PD-L1 expression have good responses to multitarget antiangiogenic drug and immune checkpoint inhibitors (ICIs). In this article, we reported a case with metastatic PSC diagnosed by Computed Tomography (CT)-guided needle biopsy treated with immunotherapy combined with antiangiogenic drugs as a neoadjuvant chemotherapy (NACT). PSC is controlled and the patient achieves successfully limb salvage treatment by surgical resection. Therefore, targeted therapy and immunotherapy can provide sufficient surgical opportunities for limb salvage in the treatment of metastatic PSC patients. Case summary: A 69-year-old male diagnosed with malignant bone tumor in the proximal femur was admitted to our hospital in June 2022 with recurrent fever as well as swelling and pain in the left thigh for twenty days. The initial computed tomography (CT) scan of the chest showed a pulmonary cavity (20 mm × 30 mm) and scattered lung masses. Subsequently, he underwent a CT-guided needle biopsy to distinguish the essence of osteolytic bone destruction and soft tissue mass in the left proximal femur which showed metastatic sarcomatoid carcinoma histology. Genetic testing revealed TERT c.-124C mutation (abundance 8.81%), TP53 p.R342 mutation (abundance 11.35%), tumor mutational burden (TMB) 7.09 muts/Mb, microsatellite stability (MSS), and PD-L1 (SP263) TPS 5% were also detected. The patient was tentatively treated with a combination of antiangiogenic drug and PD-1 inhibitor. After one course, the tumor volume significantly reduced in magnetic resonance imaging (MRI) and pathological fracture occurred in the femur after combined treatment. The patient received proximal femoral tumor resection and prosthesis replacement after defervescence. Sequentially sintilimab with anlotinib were administered for over 1 year. Finally, the local tumor was well controlled, and no obvious drug-related adverse reactions were observed. The lesions in the lung remained in partial response (PR) for more than 16 months and complete response (CR) of metastatic tumor in the proximal femur was observed through imaging examinations. Conclusion: This is the first reported case of a metastatic PSC in femur showing a favorable response to the treatment consisting of anlotinib combined with sintilimab. This case suggests that antiangiogenic therapy combined with immunotherapy may benefit patients with metastatic PSC in the preoperative adjuvant therapy for limb salvage.

Microwave-assisted intralesional curettage combined with other adjuvant methods for treatment of Campanacci III giant cell tumor of bone in distal radius: a multicenter clinical study.

Objective: To compare the clinical outcomes of microwave-assisted intralesional curettage(MAIC) with those of en bloc resection and autogenous fibular reconstruction (EBR-AFR) for treating grade III giant cell tumor of the bone (GCTB) of the distal radius and to elucidate the indications for wrist preservation surgery. Materials and methods: In this retrospective study, 19 patients with grade III GCTB of the distal radius who underwent surgery at three medical institutions were included and categorized based on their surgical pattern. Seven patients underwent MAIC and internal fixation with bone cement (MAIC group) and 12 underwent EBR-AFR (EBR-AFR group). To evaluate the function of the affected limb postoperatively, wrist range of motion, grip strength, Musculoskeletal Tumor Society (MSTS) scores were recorded. Results: The follow-up time of the MAIC group was 73.57 ± 28.61 (36-116) months, with no recurrence or lung metastasis. In contrast, the follow-up time of the EBR-AFR group was 55.67 ± 28.74 (36-132) months, with 1 case of local recurrence (8.3%, 1/12) and 1 case of lung metastasis (8.3%, 1/12). The wrist flexion, extension, supination, pronation, grip strength were better in the MAIC group than in the EBR-AFR group. Although there was no statistically significant difference in the MSTS score between the two groups, it is noteworthy that the MAIC group exhibited significantly superior emotional acceptance and hand positioning compared to the EBR-AFR group(p < 0.05). Conclusion: The functional outcomes of the MAIC group are better. The treatment strategy for grade III GCTB of the distal radius should be determined based on the specific preoperative imaging findings. Nevertheless, MAIC can be the preferred surgical approach for most patients with grade III GCTB of the distal radius, particularly for young patients.

Using 3D Printing Technology to Design Split-Piece Sleeve Prosthesis in the Revision Surgery of Tumor-Type Total Elbow Prosthetic Fractures: A Case Report.

BACKGROUND: Revision of tumor-type prosthetic fractures is very challenging in clinical work. Traditional repair methods may not be able to meet the needs of complex cases or cause greater bone damage. Therefore, more effective and reliable solutions need to be found. CASE PRESENTATION: This study presents a novel revision technique for managing fractures of tumor-type total elbow prostheses. A 57-year-old female patient was diagnosed with a left distal humeral bone tumor accompanied by pathological fracture and underwent customized tumor-type total elbow prosthesis arthroplasty. After 5 years, she experienced pain and encountered difficulty in flexing the left elbow while lifting heavy objects. The X-ray examination revealed a fracture of the distal humeral prosthesis. As a response, the elbow joint was initially explored, and the damaged component of the prosthesis was extracted. Subsequently, we utilized 3D printing technology to design a split-piece sleeve prosthesis and effectively restored the fractured left distal humerus implant. During the 2-year follow-up, The X-ray demonstrated satisfactory positioning of the prosthesis, which remained securely affixed without any indications of loosening. The Mayo Elbow Performance Score (MEPS) reached 80 points, the Musculoskeletal Tumor Society (MSTS) attained a score of 28 points, and the range of motion of the elbow was measured between 25° and 110°, revealing favorable functional outcomes. CONCLUSION: The utilization of a 3D printed split-piece sleeve prosthesis presents a viable clinical treatment strategy for addressing fractures in tumor-type elbow prostheses.

Anlotinib combined with radiotherapy and chemotherapy for recurrent pelvic osteosarcoma treatment: a case report and literature review.

At present, the treatment of recurrent pelvic osteosarcoma is too simple, and most of the patients are treated with chemotherapy, radiotherapy, and/or combined surgery. Here, we report a 29-year-old man diagnosed with local recurrent pelvic osteosarcoma. Imaging showed that the tumor had obvious enhancement and abundant blood vessels. There was no indication of surgery. After the patient's consent was obtained, we used anlotinib as a sequential treatment to chemotherapy. During the first course of adjuvant chemotherapy, we treated the patient with intensity-modulated radiotherapy (IMRT) with a total dose of 60 Gy equivalents. No disease recurrence was reported at 25 months after multimodal combination therapy.

Using 3D Printing Technology to Manufacture Personalized Bone Cement Placeholder Mold for Bone Defect Repair and Reconstruction with Infection: A Case Report.

BACKGROUND: Limb salvage surgery is the preferred treatment for most malignant bone tumors, but postoperative infection treatment is very challenging. Simultaneously controlling infection and solving bone defects are clinical treatment challenges. CASE PRESENTATION: Here we describe a new technique for treating bone defect infection after bone tumor surgery. An 8-year-old patient suffered an incision infection after osteosarcoma resection and bone defect reconstruction. In response, we designed her a personalized, anatomically matched, antibiotic-loaded, bone cement spacer mold using 3D printing technology. The patient's infection was cured, and limb salvage was successful. In follow-up, the patient had returned to normal postoperative chemotherapy and was able to walk with the help of a cane. There was no obvious pain in the knee joint. At 3 months after operation, the range of motion of the knee joint was 0°-60°. CONCLUSION: The 3D printing spacer mold is an effective solution for treating the infection with large bone defect.

Aseptic loosening of tumor prostheses in distal femur after revision surgery: a retrospective study.

BACKGROUND: Tumor prostheses of the distal femur after revision surgery is associated with high rates of aseptic loosening, which has introduced great challenges to the survival of patients, but only a few studies have evaluated their X-ray imaging. The purpose of this study was to analyze the risk factors for recurrence of aseptic loosening and make recommendations to reduce the incidence of aseptic loosening after revision surgery of tumor prostheses in the distal femur. METHOD: A retrospective analysis was performed on 23 patients who had revision surgery for distal femur prostheses due to aseptic loosening between June 2002 and June 2021. They were divided into two groups based on the condition of the prostheses after revision surgery: loosening group (9 patients) and control group (14 patients). Following the initial replacement, the length and diameter of the prosthetic intramedullary stem were measured through the standard full-length anteroposterior X-ray imaging of both lower limbs. The osteotomy length, femoral length and diameter, femoral intramedullary stem diameter, hip-knee-ankle angle (HKAA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and so on were measured as well. Following that, statistical analysis was performed. RESULTS: Patients in the loosening group had statistically significant differences in the ratio of prostheses length to femur length (71.89 ± 6.62) and the ratio of intramedullary stem diameter to femoral diameter (25.50 ± 6.90) (P < 0.05), when compared to the control group. The HKAA (175.58 ± 2.78), mLDFA (94.42 ± 2.57), and the deviation angle between the lower limb alignment and the tibial prostheses force line (2.23 ± 1.09) in the loosening group were significantly different from those in the control group (P < 0.05) on postoperative radiographs of the entire length of the lower limbs. The lowest score in intramedullary manubrium I indicated less osteolysis, while the highest score in intramedullary manubrium III indicated the most serious osteolysis, and the difference was statistically significant (P < 0.05). CONCLUSIONS: Our study suggests that the use of longer and thicker intramedullary stems can effectively decrease the occurrence of aseptic loosening. Additionally, it is important to avoid using the original prostheses and reconstruct the standard line of lower limb force to further reduce the incidence of aseptic loosening. It is crucial to closely monitor the distal segment of the intramedullary stem for osteolysis after surgery.

Radiological outcomes of PEEK rods in patients with lumbar degenerative diseases: A minimum 5-year follow-up.

Purpose: To determine the long-term radiological outcomes of PEEK rods in patients with lumbar degenerative diseases. Methods: Radiological outcomes of cohort cases with lumbar degenerative diseases following PEEK rods were retrospectively studied. Disc height index (DHI) and range of motion (ROM) were measured by x-rays. The CT scans and reconstruction were used to determine screw breakage, rods fracture, screw loosening and intervertebral bony fusion status. The MRI scans were used to evaluate the changes of intervertebral discs at the non-fusion segments and adjacent segments in terms of Pfirrmann Classification. Results: A total of 40 patients completed the mean of 74.8 ± 9.6 months follow-up, with 32 patients undergoing hybrid surgery and 8 patients undergoing non-fusion surgery. The mean DHI changed from preoperative 0.34 to 0.36 at the final follow-up and the ROM declined from 8.8° preoperatively to 3.2° at the final visit, however, both had no statistical differences. Of the 40 levels underwent non-fusion procedure, 9 levels showed disc rehydration with 7 patients from Grade 4 to Grade 3 and 2 patients from Grade 3 to Grade 2. The other 30 cases did not show distinctive change. No screw loosening or rods breakage were detected during the follow-up periods. Conclusion: PEEK rods have obvious protective effects on degenerated intervertebral disc of non-fusion segments and the incidence of complications related to internal fixation is low. PEEK rods pedicle screw system is safe and effective in the treatment of lumbar degenerative diseases.

Lumbar disc rehydration after dynamic stabilization: A systematic review.

BACKGROUND: Interbody fusion combined with posterior screw fixation is a traditional method used for treating lumbar degenerative disease (LDD). But in recent years, there have been more and more reports about its complications. Dynamic Stabilization Systems (DSS) are another method for the treatment of LDD, but the clinical results are still inconclusive. The objective of this study is to review, analyze, and discuss the probability of disc rehydration by DSS designed for LDD by systematically reviewing previous relevant studies. METHODS: The Pubmed, Web of Science, and Embase databases were searched using keywords for articles published before June 2022. The following keywords were used: rehydration, rehydrated, lumbar, spine, disc, spinal, degenerative disc disease, degenerative spine disease, vertebrae, vertebral column, thoracolumbar, and lumbosacral. The included studies were printed in English. Two independent investigators compiled all data. For the quality assessment, the Newcastle-Ottawa Scale was used to evaluate case-control studies, while the Joanna Briggs Institute critical appraisal checklist was used to evaluate the case series studies. RESULTS: This systematic review included 7 studies comprised of 5 case series and 2 case-control studies. Seven articles involving 199 cases were enrolled for the data extraction. Of the 199 cases, 55 cases observed rehydration, as evaluated by Pfrimann grading on magnetic resonance imaging. The rehydration rate was 27.6% (55/199). DSS can provide positive clinical outcomes. Both visual analog scale and Oswestry Dysfunctional Index scores were significantly improved at the final follow-up. CONCLUSION: DSS may promote disc rehydration and delay the development of LDD to some extent. Mechanical stretch may play an important role in the progress of intervertebral disc rehydration. It provides important evidence for the clinical application of DSS.

Comprehensive conservative treatment for multiple metastases of skull osteosarcoma: A case report.

Background: Skull osteosarcoma is relatively rare, and it is difficult to be diagnosed according to medical history and imaging examination due to the complex structure and diverse components of the brain. Consequently, there is only a limited number of patients who can undergo neoadjuvant chemotherapy before the operation. Although neoadjuvant chemotherapy plays an important role in the treatment of osteosarcoma, there is still a "bottleneck" in the current treatment method which when pulmonary metastasis occurs, or surgical treatment is not Enneking appropriate. Under such circumstances, the choice of treatment can be an issue. Case: A 16-year-old male patient with multiple metastases of skull osteosarcoma was reported. The patient suffered not only tinnitus and hearing loss in the right ear but also right facial paralysis and headache. The preoperative brain MRI showed a tumor in the right cerebellopontine angle (CPA) area. He underwent skull tumor resection at another hospital in November 2018, during which process the biopsy revealed epithelioid osteoblastoma-like osteosarcoma. The patient had supplemental radiotherapy 1 month after surgery because of tumor recurrence. 32 months afterward, pulmonary metastases and multiple bone metastases were found. Then the patient underwent multiple conservative treatments which include Denosumab, Anlotinib, and DIA (cisplatin + ifosfamide + doxorubicin) chemotherapy at our hospital. After a series of 6 cycles of treatment, the patient can walk without aid. Lactate dehydrogenase (LDH) and Alkaline phosphatase (AKP) returned to a normal level. Fluorodeoxyglucose (FDG) metabolism in all bone metastases decreased to normal except for the ones in the proximal left femur, and the FDG metabolism in the left femur is significantly lower than that before treatment. Multiple bone metastases showed different extents of high-density calcification, and the volume of the local bone metastases has been reduced significantly. The patient's condition stayed stable at latest follow-up. Conclusion: We found that multiple conservative treatments, which include Denosumab, Anlotinib and DIA chemotherapy, can improve patients' life quality, and help avoid further osteolytic destruction for patients with skull osteosarcoma and multiple metastases. Its specific mechanism and scope of the application still need to be further studied.

A Comparison of Negative Pressure and Conventional Therapy in Spine Infections: A Single-Center Retrospective Study.

Purpose: To investigate the effectiveness and safety of negative-pressure wound therapy (NPWT) in treating primary spinal infections. Methods: Patients who underwent surgical treatment for primary spinal infection between January 2018 and June 2021 were retrospectively evaluated. They were divided into two groups based on the type of surgery: one that underwent negative-pressure wound therapy (NPWT) and another that underwent conventional surgery (CVSG-Posterior debridement, bone grafting, fusion, and internal fixation in one stage). The two groups were compared in terms of the total operation time, total blood loss, total postoperative drainage, postoperative pain score, time for the postoperative erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) to return to normal, postoperative complications, treatment time, and recurrence rate. Results: A total of 43 cases of spinal infection were evaluated, with 19 in the NPWT group and 24 in the CVSG group. The NPWT group had a superior postoperative drainage volume, antibiotic use time, erythrocyte sedimentation rate and CRP recovery times, VAS score at 3 months after the operation, and cure rate at 3 months after operation compared with the CVSG group. There were no significant variations in the total hospital stay and intraoperative blood loss between the two groups. Conclusions: This study supports the use of negative pressure in the treatment of a primary spinal infection and indicates that it has a notably better short-term clinical effect than conventional surgery. Additionally, its mid-term cure rate and recurrence rate are more desirable than those of conventional treatments.

Denosumab combined with precision radiotherapy for recurrent giant cell tumor of the thoracic spine: a case report and literature review.

Giant cell tumors of the spine have a high recurrence rate owing to their special anatomical site; hence, further treatment after recurrence is very challenging. Achieving effective tumor control and improving the long-term quality of life of the patients are the main treatment purposes to consider for recurrent giant cell tumors of the spine. A patient showing giant cell tumor recurrence of the thoracic spine after curettage received denosumab combined with precision radiotherapy, through which the tumor gained good control and the patient could regain normal functioning. A review of the relevant literature suggested that denosumab combined with radiotherapy is an effective new approach for the treatment of recurrent giant cell tumors of the spine.

Risk factors for fracture in patients with fibrous dysplasia of the proximal femur.

OBJECTIVE: The primary aim of this retrospective observational clinical study was to explore the risk factors for fracture in patients with fibrous dysplasia (FD) of the proximal femur. METHODS: We investigated body mass index, bilateral radiographs on both sides, femoral neck shaft angle measurements, and markers of bone metabolism in patients with FD of the proximal femur according to whether or not they had sustained a hip fracture. Nine clinical parameters (age, sex, clinical classification, anatomic classification, femoral neck shaft angle, and procollagen type 1 N-terminal propeptide, C-terminal telopeptide of type I collagen, and osteocalcin levels) were selected for univariate analysis. Factors that were significant in univariate analysis were then subjected to multivariate logistic analysis. RESULTS: Clinical classification, anatomic classification, femoral neck shaft angle, and the osteocalcin level were identified to be statistically significant risk factors for fracture in univariate analysis. Anatomic classification, femoral neck shaft angle, and the osteocalcin level remained significant risk factors in multivariate analysis. CONCLUSIONS: Anatomic classification, femoral neck shaft angle, and the osteocalcin level are important risk factors for fracture in patients with FD of the proximal femur and could be used to guide implementation of a fracture prevention strategy in these patients.

Conservative surgery with microwave ablation for recurrent bone tumor in the extremities: a single-center study.

BACKGROUND: Surgical treatment for recurrent bone tumors in the extremities still presents a challenge. This study was designed to evaluate the clinical value of microwave ablation in the treatment of recurrent bone tumors. METHODS: We present 15 patients who underwent microwave ablation for recurrent bone tumors during the last 7 years. The following parameters were analyzed for outcome evaluation: general condition, surgical complications, local disease control, overall survival, and functional score measured using the Musculoskeletal Tumor Society (MSTS) 93 scoring system. RESULTS: Percutaneous microwave ablation in one patient with osteoid osteoma and another with bone metastasis resulted in postoperative pain relief. Thirteen patients received intraoperative microwave ablation before curettage or resection, including those with giant cell tumors of bone (6), chondroblastoma (2), osteosarcoma (2), undifferentiated sarcoma (1), and bone metastases (2). All patients achieved reasonable local tumor control in the mean follow-up of 29.9 months. The functional score was 24.1 for the 15 patients 6 months after the operation. Four patients had tumor metastasis and died, whereas 3 patients with tumors survived, and the remaining 8 patients without the disease survived. CONCLUSIONS: Microwave ablation represents an optional method for local control in treating recurrent bone tumors in the extremities.

Treatment of lumbar brucella spondylitis with negative pressure wound therapy via extreme lateral approach: A case report.

Brucella spondylitis (BS) is a specific spinal infection. Surgical treatment is required for Brucella spondylitis that has caused neurological symptoms in the lower extremities and developed an intraspinal abscess. The main purpose of surgery is to remove the lesion and restore the stability of the spine. However, both the anterior approach and the posterior approach cannot completely remove the lesions, resulting in a low cure rate and a certain recurrence rate. Although anterior or posterior debridement is more thorough, it is unbearable for some patients with poor general condition. In this study, for the first time, a negative pressure wound therapy (NPWT) device was introduced into the intervertebral space through the extreme lateral approach to treat a patient with Brucella spondylitis. We summarize the treatment process, and discuss the feasibility and effectiveness of this surgical approach through 1-year follow-up.

Classification and reconstruction of femoral bone defect in the revision of aseptic loosening of distal femoral endoprostheses: a 10-year multicenter retrospective analysis.

OBJECTIVE: This study proposes a system for classifying the aseptic loosening of distal femoral endoprostheses and discusses reconstruction methods for revision surgery, based on different classification types. METHODS: We retrospectively analyzed the data of patients who received revision surgery for aseptic loosening in distal femoral tumor endoprosthesis from January 2008 to December 2020 at 3 bone tumor treatment centers in China. Based on the patient imaging data, we proposed a classification system for the aseptic loosening of distal femoral endoprostheses and discussed its revision surgery strategy for various bone defects. RESULTS: A total of 31 patients were included in this study, including 21 males and 10 females aged 15-75 y (average: 44.3 y). First-revision surgery was performed on 24 patients, whereas second-revision surgery was conducted on 7 patients. The 31 patients were classified into different types based on the degree of aseptic loosening: Type I, 12 patients (38.7%); Type IIa, 7 patients (22.5%); Type IIb, 7 patients (22.5%); Type III, 4 patient (12.9%); and Type IV, 1 patient (3.2%). For type I, 11 patients underwent revisions with standard longer-stem prostheses (one with the original prosthesis), and one patient had the original prosthesis plus cortical allograft strut. For type II (a and b), 10 patients underwent revisions with original prosthesis or longer-stem prosthesis and 4 patients combined with cortical allograft strut. For type III, one patient underwent revision with a longer-stem prosthesis and the other 3 patients with a custom short-stem prosthesis. For type IV, only one patient underwent revision with a custom short-stem prosthesis. CONCLUSIONS: Aseptic loosening of the distal femoral prosthesis can be divided into 4 types: type I, type II (a, b), type III and type IV. The reconstruction methods of our centers for different types of bone defects can offer some reference value in the revision of aseptic loosening.

Postoperative discal pseudocyst after percutaneous endoscopic transforaminal discectomy treated by drainage: Case report.

RATIONALE: This article reports 2 cases of symptomatic postoperative discal pseudocysts (PDP), a rare complication of percutaneous endoscopic transforaminal lumbar discectomy (PELD). In this report, we propose a possible mechanism of PDP and introduce an effective therapeutic strategy. To our knowledge, there have been no reports of the use of indwelling drainage techniques for the PDP treatment after PELD. PATIENT CONCERNS: Herein, we report 2 cases of PDP after PELD in our hospital. Both patients had disc herniation at the L4/5 level, and the symptoms of low back pain and radiculopathy were significantly relieved after PELD. However, the signs in both 2 cases recurred 20 days after surgery. MRI indicated PDP in both 2 patients with high intensity on T1- and T2-weighted imaging in the primary surgical area. INTERVENTIONS: Given the progressive symptoms in both cases, PELD was performed again and 3-lumen drainage catheters were placed at the surgical site for adequate drainage. OUTCOMES: The patient's symptoms were significantly relieved after adequate drainage and disappeared 3 months after surgery. There was no clinical or MRI recurrence at the 6-month follow-up. CONCLUSION: According to operative findings, we found that PDP symptoms may not be attributable mainly to cyst compression but to the excessive accumulation of local inflammatory factors. Treatment of PELD combined with indwelling drainage is feasible and effective in treating PDP.

Successful limb salvage in progressive proximal tibia osteosarcoma following denosumab chemotherapy: A case report.

RATIONALE: Osteosarcoma (OS) is a primary malignant bone tumor that originates in the mesenchymal tissue. It is the most common type of pleomorphic tumor occurring in children and adolescents. Currently, there is no established systematic treatment for OS that progresses during standard preoperative chemotherapy. PATIENT CONCERNS AND DIAGNOSES: We describe a 14-year-old male patient with a 4-month history of pain in the upper right leg. Based on the results of percutaneous biopsy, a diagnosis of OS was made. After admission, the patient was treated with first-line chemotherapy agents. After a single course of treatment, the tumor progressed locally and no limb salvage was feasible. INTERVENTIONS AND OUTCOMES: Intervention with denosumab combined with chemotherapy led to a significant reduction in tumor volume and ossification of soft tissue, which successfully resulted in limb salvage rather than amputation. The patient showed no evidence of recurrent or distant metastasis at 6-month follow-up. LESSONS: Treatment with receptor activator of nuclear factor-ĸB ligand inhibitor denosumab combined with standard chemotherapy is effective for advanced OS progressing after chemotherapy. We recommend denosumab therapy for successful limb salvage in patients with high-grade OS associated with osteolytic bone destruction and refractory to preoperative neoadjuvant chemotherapy.

Radiographic Assessment of Aseptic Loosening of Tumor-Type Knee Prosthesis in Distal Femur.

OBJECTIVE: To measure the full-length anteroposterior and lateral radiographs of lower limbs after the resection of a tumor in the distal femur and tumor-type knee prosthesis replacement and to analyze the factors leading to aseptic loosening of the prosthesis. METHODS: A total of 26 cases of tumor-type knee prosthesis replacement or revision due to the distal femoral tumor at our hospital from January 2007 to December 2019 were retrospectively analyzed. The patients were divided into the loosening and unloosening groups depending on whether aseptic loosening occurred after surgery. Full-length anteroposterior and lateral radiographs of lower limbs were used to measure bone resection length, length of prosthesis, distance of proximal apex of the medullary stem of the femoral prosthesis from the maximum arc of the anterior femoral arch, diameter of the medullary stem, etc. Data were analyzed, and the risk factors for aseptic loosening of the prosthesis were explored. RESULTS: The ratio of the prosthetic length to the femoral length (63.72 ± 5.21) and the ratio of the femoral medullary stem diameter to the femoral diameter (26.03 ± 8.45) were smaller in the loosening group than in the unloosening group. The difference was statistically significant (p < 0.05). The distance between the apex of the medullary stem and the maximum arc of the anterior femoral arch was significantly shorter in the loosening group (3.47 ± 2.96) than in the unloosening group, and the difference was statistically significant (p < 0.05). The measurement of the lower limb alignment showed significant differences between the loosening and unloosening groups in terms of HKAA, mLDFA, and distance between the lower limb alignment and the center of the knee joint (p < 0.05). The logistic regression analysis showed that less than 30% ratio between the medullary stem diameter and the femoral diameter, less than 3 cm distance between the apex of the medullary stem and the maximum curvature of the anterior arch of the femur, distance between the lower limb alignment and the center of the knee joint, and presence of varus knee and valgus knee after the surgery were the risk factors for aseptic loosening of the prosthesis. CONCLUSIONS: The diameter of the femoral medullary stem of the prosthesis, the apex position of the prosthetic stem, and the lower limb alignment are the risk factors for aseptic loosening of the prosthesis.

A New Simple and Practical Clinical Classification for Tenosynovial Giant Cell Tumors of the Knee.

OBJECTIVE: To propose a simple and practical clinical classification for tenosynovial giant cell tumor (TGCT) of the knee. METHODS: A retrospective study was conducted to verify the value and significance of this clinical classification. TGCT growth patterns, knee joint capsule, and bone erosion were applied to establish this novel clinical classification. Seventy-eight patients who underwent surgery for TGCT from 2008 to 2016 were identified. This novel clinical classification was retrospectively applied to patients' existing classification, and patients with different TGCT types were statistically compared to verify the significance of the clinical classification. RESULTS: The clinical classification included three types and four subtypes. Type 1: localized TGCT, Subtype 1a: localized intra-articular TGCT, Subtype 1b: localized extra-articular TGCT. Type 2: diffuse TGCT, Subtype 2a: diffuse intra-articular TGCT with bone normal, Subtype 2b: diffuse intra-articular TGCT with bone destruction. Type 3: diffuse TGCT across the knee joint capsule. The mean follow-up time for the 78 patients was 59.6 months. Twenty-one patients were in Subtype 1a, four were Subtype 1b, 38 were Subtype 2a, seven were Subtype 2b, and eight were Type 3. Oncological results and surgical complications differed significantly (P = 0.000, P = 0.000). The mean Musculoskeletal Tumor Society functional scores differed significantly at 27.8 for Type 1 patients, 22.9 for Type 2 patients, and 17.0 for Type 3 patients (P = 0.000). CONCLUSIONS: This clinical classification can be easily used to evaluate TGCT of all knees prior to surgery or other treatments and can help determine surgical options.