This study presents the case of a 40-year-old male patient after renal transplantation. The CT scan revealed a large mass in the lower abdomen and pelvis, with a branch of the right external iliac artery intersecting the growth. After a comprehensive examination, it was shown that the mass originated from the transplanted kidney, and a radical nephrectomy (including the mass) was performed. We document a case of atypical angiomyolipoma (AAM) occurring in a transplanted kidney. This article reports the case study and a brief literature review of the clinical presentation, diagnosis and treatment of AAM.

UNASSIGNED: Research on return to sport and psychological recovery in anterior cruciate ligament (ACL) revision remains scarce. The clinical efficacy of artificial ligament in ACL revision requires further exploration. Our objectives were (1) to compare the midterm clinical outcomes of artificial ligament versus allogenic tendon graft in ACL revision and (2) to analyze the effects of employing artificial ligament on return to sport and psychological recovery in ACL revision.
UNASSIGNED: This cohort study included the cases receiving ACL revision from 2014 to 2021 in Sports Medicine Department of Huashan Hospital. The grafts used were Ligament Advanced Reinforcement System (LARS) and ATT allograft. We recorded patients\' baseline data. The final follow-up assessment included subjective scales, physical examination, and return to sport status. We recorded the rates and timings of return to sport. Subjective scales included the 2000 International Knee Documentation Committee (IKDC) subjective score, Lysholm Knee Scaling Score (LKSS), Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner activity score, Marx activity rating score, and Anterior Cruciate Ligament-Return to Sport after Injury (ACL-RSI). Anterior knee stability was assessed using the KT-1000 arthrometer.
UNASSIGNED: Fifty cases (LARS group: 27; ATT group: 23) enrolled and 45 (LARS group: 23; ATT group: 22) completed evaluations with a median follow-up period of 49 months. At recent follow-up, LARS group outperformed in knee stability (1.0 ± 1.9 mm vs. 2.6 ± 3.0 mm, P = 0.039), confidence (86.7 ± 12.4 vs. 69.4 ± 18.6, P < 0.001), emotion (82.7 ± 11.3 vs. 70.7 ± 16.2, P < 0.001), KOOS knee function (78.7 ± 8.8 vs. 69.5 ± 11.0, P = 0.003), quality of life (79.1 ± 16.1 vs. 66.4 ± 19.5, P = 0.014), Tegner score (6.3 ± 1.9 vs. 5.2 ± 2.1, P < 0.001), and Marx activity score (10.7 ± 3.7 vs. 7.9 ± 4.0, P = 0.012). The LARS group had significantly higher return rates: recreational (91.3 % vs. 63.6 %, P = 0.026), knee cutting and pivoting (87.0 % vs. 59.1 %, P = 0.035), competitive (78.3 % vs. 45.5 %, P = 0.023), and pre-injury (56.5 % vs. 27.3 %, P = 0.047). For return timings, the LARS group was earlier at recreational (11.2 ± 3.9 vs. 27.8 ± 9.0 weeks, P < 0.001), knee cutting and pivoting (17.2 ± 5.8 vs. 35.6 ± 13.8 weeks, P < 0.001), competitive (24.8 ± 16.2 vs. 53.2 ± 22.0 weeks, P < 0.001), and pre-injury levels (32.8 ± 11.0 vs. 72.8 ± 16.9 weeks, P < 0.001).
UNASSIGNED: In ACL revision, using LARS demonstrated improved joint stability and functionality compared to using allogenic ATT four years postoperative. Patients accepting the LARS procedure exhibited higher rates and earlier timings of return to various levels of sport, indicating enhanced confidence and emotional resilience.
UNASSIGNED: In ACL revision, the choice of artificial ligament to shorten recovery time, thereby enabling patients to return to sport more quickly and effectively, is thought-provoking. The research value extends beyond mere graft selection, guiding future clinical trials and studies. This research enhances our understanding of the application value of artificial ligament in ACL revision, emphasizing the importance of psychological recovery and updating our perceptions of return to sport levels post-revision. It stimulates exploration into personalized rehabilitation programs and treatment strategies, aiming to optimize clinical outcomes and meet the real-world needs of patients with failed ACL reconstruction.

This study aimed to compare the clinically established autologous extrasynovial tendon graft to a newly developed tissue-engineered allograft (Eng-allograft) in terms of functional outcomes following flexor tendon reconstruction in a canine model. The second and fifth flexor digitorum profundus (FDP) tendons from 16 dogs were transected and repaired in Zone II. After 6 weeks of cage activity, the repaired tendons were intentionally ruptured, creating a clinically relevant model for reconstruction. The re-ruptured FDP tendons were then reconstructed using either the clinically standard autologous extrasynovial tendon graft or the Eng-allograft, which had been revitalized with autologous bone marrow-derived mesenchymal stem cells (BMSCs) and synovialized using carbodiimide derivatized synovial fluid (cd-SYN). Following 12 weeks of postoperative rehabilitation, the functional outcomes of the surgical digits were evaluated. The Eng-allograft group exhibited improved digital function, including lower digit work of flexion and reduced adhesion status, while maintaining similar tendon gliding resistance compared to the autograft group. However, the failure load of both the distal and proximal host/graft conjunctions in the Eng-allograft group was significantly lower than that of the autograft group with higher graft rupture at the host-graft junction. In conclusion, the decellularized allogenic intrasynovial tendon, when revitalized BMSCs and synovialized with cd-SYN, demonstrates positive effects on digital function improvement and adhesion reduction. However, the healing at both proximal and distal graft/host junctions is far lower than the autograft. Further research is needed to enhance the healing capacity of allograft conjunctions, aiming to achieve a comparable level of healing seen with autografts.

UNASSIGNED: Congenital pseudarthrosis of the tibia is a limb deformity, which can be distressing for the affected patients and the pediatric orthopedic surgeons involved. We hypothesized that the modified McFarland procedure would avoid fractures and even have a corrective effect on the affected tibia in congenital pseudarthrosis of the tibia patients. Toward this end, we evaluated the midterm results of treating congenital pseudarthrosis of the tibia patients of Crawford Type I and II with allograft bypass combined with long-term bracing.
UNASSIGNED: This study retrospectively evaluated 7 patients with congenital pseudarthrosis of the tibia who were treated with allograft bypass combined with long-term bracing between 2009 and 2018. The median follow-up was 7.0 years (range 3.8-10.0 years). The medical records and radiographs were reviewed for demographic data, clinical characteristics, outcomes, and complications.
UNASSIGNED: At the time of the last follow-up, all allografts revealed complete consolidation in the patients\' tibiae at both ends. All patients presented no functional restriction of the lower limbs and no amputation or non-union has occurred. Most of the obvious deformities of the tibia diaphysis or ankle joint were corrected. Two complications occurred that required successful revision surgery.
UNASSIGNED: In this series of seven congenital pseudarthrosis of the tibia patients, the allograft bypass technique showed satisfactory midterm results and validated our hypothesis. For congenital pseudarthrosis of the tibia patients of Crawford Type I and II, this procedure combined with long-term bracing, which involves the affected leg only, can delay or possibly prevent fractures, decrease tibial malalignment, and preserve leg length.
UNASSIGNED: level IV.

Bone grafts are typically categorized into four categories: autografts, allografts, xenografts, and synthetic alloplasts. While it was originally thought that all bone grafts should be slowly resorbed and replaced with native bone over time, accumulating evidence has in fact suggested that the use of nonresorbable xenografts is favored for certain clinical indications. Thus, many clinicians take advantage of the nonresorbable properties/features of xenografts for various clinical indications, such as contour augmentation, sinus grafting, and guided bone regeneration, which are often combined with allografts (e.g., human freeze-dried bone allografts [FDBAs] and human demineralized freeze-dried bone allografts [DFDBAs]). Thus, many clinicians have advocated different 50/50 or 70/30 ratios of allograft/xenograft combination approaches for various grafting procedures. Interestingly, many clinicians believe that one of the main reasons for the nonresorbability or low substitution rates of xenografts has to do with their foreign animal origin. Recent research has indicated that the sintering technique and heating conducted during their processing changes the dissolution rate of hydroxyapatite, leading to a state in which osteoclasts are no longer able to resorb (dissolve) the sintered bone. While many clinicians often combine nonresorbable xenografts with the bone-inducing properties of allografts for a variety of bone augmentation procedures, clinicians are forced to use two separate products owing to their origins (the FDA/CE does not allow the mixture of allografts with xenografts within the same dish/bottle). This has led to significant progress in understanding the dissolution rates of xenografts at various sintering temperature changes, which has since led to the breakthrough development of nonresorbable bone allografts sintered at similar temperatures to nonresorbable xenografts. The advantage of the nonresorbable bone allograft is that they can now be combined with standard allografts to create a single mixture combining the advantages of both allografts and xenografts while allowing the purchase and use of a single product. This review article presents the concept with evidence derived from a 52-week monkey study that demonstrated little to no resorption along with in vitro data supporting this novel technology as a \"next-generation\" biomaterial with optimized bone grafting material properties.

The study is to evaluate incorporation of a bone-anterior cruciate ligament-bone (B-ACL-B) allograft in anterior cruciate ligament (ACL) reconstruction in a rabbit model. A total of 61 New Zealand white rabbits were used, with 23 donor rabbits for harvesting B-ACL-B allografts and 38 recipient rabbits undergoing unilateral ACL reconstruction with B-ACL-B allograft. Animals were euthanized for biomechanical testing, micro-computed tomography examination, histological analysis, multi-photon microscopy and transmission electron microscopy testing at 2, 4 and 8 weeks after surgery. Gross inspection and radiographs confirmed the intact ACL allograft in the proper anatomic position. Progressive healing occurred between the bone block and the bone tunnel as demonstrated by a gradual increase in average bone volume fraction and total mineral density at 4 and 8 weeks. Histological analysis showed new bone formation at the bone block-tunnel interface, with maintenance of the native ACL enthesis. Ultrastructural analysis demonstrated the maintenance of overall collagen matrix alignment, while there was repopulation with smaller diameter collagen fibrils. There was no significant difference between 4 and 8 weeks in mean failure force (p = 0.39) or stiffness (p = 0.15) for the B-ACL-B allografts. This study demonstrates the restoration of the normal anatomy of the ACL and progressive graft incorporation and remodeling using a B-ACL-B allograft for ACL reconstruction in the rabbit knee.

BACKGROUND: Fibrous dysplasia associated with aneurysmal bone cyst (ABC)-like changes in the right proximal femur has a low incidence. It is considered more difficult to make early diagnosis than for single fibrous dysplasia.
METHODS: A 14-year-old woman was admitted because of persistent pain in the right hip and abnormal gait over the previous 2 mo. She had no history of present or past illness. Preoperative photography, enhanced computed tomography, and magnetic resonance imaging showed ground-glass appearance with cortical scalloping and expansion of the right proximal femur and femoral neck. Pathological examination by preoperative puncture biopsy revealed fibrous dysplasia of the right proximal femur. The patient was diagnosed with fibrous dysplasia based on medical history, physical examination, and results of laboratory, imaging and pathological examinations. According to final pathological examination, the patient was diagnosed with fibrous dysplasia of the right proximal femur associated with ABC. Curettage and allograft along with fixation of compression screws was performed for fibrous dysplasia associated with ABC-like changes. No obvious allograft absorption, loosening of fixation, or secondary fracture were observed during 6-months\' follow-up with re-examination by plain radiography and computed tomography. Fibrous dysplasia associated with ABC-like changes in the right proximal femur has a low incidence and early diagnosis is considered more difficult than for single fibrous dysplasia.
CONCLUSIONS: We report a cases of fibrous dysplasia associated with ABC-like changes in the right proximal femur treated with curettage and allograft along with hip compression screws.

OBJECTIVE: This study investigated whether exosomes from LPS pretreated bone marrow mesenchymal stem cells (LPS pre-MSCs) could prolong skin graft survival.
METHODS: The exosomes were isolated from the supernatant of MSCs pretreated with LPS. LPS pre-Exo and rapamycin were injected via the tail vein into C57BL/6 mice allografted with BALB/c skin; graft survival was observed and evaluated. The accumulation and polarization of macrophages were examined by immunohistochemistry. The differentiation of macrophages in the spleen was analyzed by flow cytometry. For in vitro, an inflammatory model was established. Specifically, bone marrow-derived macrophages (BMDMs) were isolated and cultured with LPS (100 ng/ml) for 3 h, and were further treated with LPS pre-Exo for 24 h or 48 h. The molecular signaling pathway responsible for modulating inflammation was examined by Western blotting. The expressions of downstream inflammatory cytokines were determined by Elisa, and the polarization of macrophages was analyzed by flow cytometry.
RESULTS: LPS pre-Exo could better ablate inflammation compared to untreated MSC-derived exosomes (BM-Exo). These loaded factors inhibited the expressions of inflammatory factors via a negative feedback mechanism. In vivo, LPS pre-Exo significantly attenuated inflammatory infiltration, thus improving the survival of allogeneic skin graft. Flow cytometric analysis of BMDMs showed that LPS pre-Exo were involved in the regulation of macrophage polarization and immune homeostasis during inflammation. Further investigation revealed that the NF-κB/NLRP3/procaspase-1/IL-1β signaling pathway played a key role in LPS pre-Exo-mediated regulation of macrophage polarization. Inhibiting NF-κB in BMDMs could abolish the LPS-induced activation of inflammatory pathways and the polarization of M1 macrophages while increasing the proportion of M2 cells.
CONCLUSIONS: LPS pre-Exo are able to switch the polarization of macrophages and enhance the resolution of inflammation. This type of exosomes provides an improved immunotherapeutic potential in prolonging graft survival.

BACKGROUND: Allograft reconstruction following the resection of malignant bone tumors is associated with high rates of complications and failures. This study aimed to evaluate the efficacy and current problems of allograft reconstruction techniques to optimize treatment strategies at our center.
METHODS: Thirty-eight cases (16 men and 22 women), who were diagnosed with malignant bone tumors and had undergone allograft reconstruction, were recruited. Allograft was fixed by intramedullary nail, single steel plate, double plate, and intramedullary nail combined plate in 2, 4, 17, and 15 cases, respectively. Allograft union, local recurrence, and complications were assessed with clinical and radiological tests. Tumor grade was assessed using the Enneking staging of malignant bone tumors. Functional prognosis was evaluated by the Musculoskeletal Tumor Society (MSTS) scoring system.
RESULTS: Intercalary and osteoarticular reconstructions were performed in 32 and 6 cases, respectively. Six patients underwent reoperation related to allograft complications, four patients had local recurrence, and three patients with allograft fracture underwent allograft removal. A total of eight host-donor junctions showed nonunion, including seven cases (18.4%) in diaphysis and one case (3.1%) in metaphysis (p < 0.01). Host rejection and secondary osteoarthritis occurred in nine and two cases, respectively. No deep infection and internal fixation device fracture occurred. The overall allograft survival rate was 81.6%. Postoperative MSTS score of patients with allograft survival was 26.8 ± 2.9, indicating a significant improvement as compared to their preoperative function.
CONCLUSIONS: Allograft represents an excellent choice for intercalary bone defects after malignant bone tumor resection. Robust internal fixation protection across the whole length of the allograft is an important prerequisite for the survival of the allograft, while multidimensional osteotomy, intramedullary cement reinforcement, and pedicled muscle flap transfer can effectively improve the survival rate and healing rate of the allograft.

BACKGROUND: Inter body spacers have been widely used in patients undergoing spinal fusion surgery; however, it is not clear whether one implant shows superior clinical outcomes compared with the other. This systematic review and meta-analysis comprehensively evaluated the radiologic outcomes and patient-reported outcomes of structural allograft versus polyetheretherketone (PEEK) implants in patients undergoing spinal fusion surgery.
METHODS: Extensive literature searches were conducted on online databases, including MEDLINE, Embase, Web of Science, Cochrane Central Register of Controlled Trials, and Cochrane Library, until January 2023. The present study adheres to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, and the Newcastle-Ottawa Scale and Cochrane Collaboration Risk of Bias tool were used to assess the quality of the included studies.
RESULTS: Fifteen studies, encompassing 8020 patients, met the eligibility criteria. The results indicate that structural allografts show a higher fusion rate compared with PEEK implants (odds ratio [OR], 1.88; 95% confidence interval [CI], 1.05-3.37; P ＝0.03; I2 = 71%). In addition, the structural allograft group also had a lower pseudarthrosis rate (OR, 0.40; 95% CI, 0.20-0.80; P = 0.009; I2 = 75%) and reoperation rate (OR, 0.46; 95% CI, 0.26-0.81; P = 0.007; I2 = 38%).
CONCLUSIONS: Our systematic review and meta-analysis show that structural allograft has a higher fusion rate compared with PEEK implants in patients undergoing spinal fusion surgery. In addition, structural allograft has a lower pseudarthrosis rate and reoperation rate.