Allograft Reconstruction Research Articles

Reconstruction of a Chronic, Retracted Proximal Hamstring Rupture Using Achilles Tendon Allograft

Background: Chronic, retracted proximal hamstring ruptures are a challenging problem and can be a significant cause of pain and disability if left untreated. Allograft augmentation is a viable surgical option with good clinical outcomes. Indications: Indications are symptomatic patients with chronic hamstring ruptures unable to be primarily repaired. Patients typically present with pain, instability, or lack of push of strength. Technique Description: An L-shaped extensile incision is made at the level of the gluteal crease. The gluteus maximus is retracted proximally. The sciatic nerve is identified, neurolysed, and tagged. Following the release of adhesions of the native tendon and confirmation of the inability to complete a primary repair, the Achilles tendon allograft is prepared. The allograft is incorporated with the native tendon and the subsequent hamstring construct is fixed and reduced to the ischial tuberosity with suture anchors. After copious irrigation, the incision is closed with Monocryl and Dermabond (Johnson and Johnson) and a sterile dressing is applied. The patient is placed in a hip brace locked in extension. Results: In a study by Rust et al, examining 72 patients with proximal hamstring ruptures, patients who underwent allograft reconstruction reported activities of daily living and postoperative sports activity equal to those of chronic repair, and inferior to those of acute repair. However, there were no significant differences between groups for patient-reported outcomes among acute and chronic repairs and allograft reconstruction. Moreover, a systematic review, by Van Der Made et al, published in the American Journal of Sports Medicine, included 13 studies that found that Achilles allograft repair for delayed proximal hamstring repair results in outcomes comparable to acute primary repair. Discussion/Conclusion: Although the literature on chronic proximal hamstring repair is fairly limited, studies have shown that proximal hamstring repair with allograft augmentation can be favorable in symptomatic patients. Allograft augmentation for chronic, retracted proximal hamstring ruptures provides increased functional outcomes in comparison with nonoperative management. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Distal Radius Allograft for Glenohumeral Instability: A Novel Osteochondral Allograft Reconstruction Option in the Setting of Glenoid Bone Loss

Background: Distal tibial allograft (DTA) reconstruction for glenoid bone loss is nonanatomic, as it does not match the glenoid radius of curvature (ROC) in the anterior-posterior (AP) plane. The dorsal articular portion of the distal radius has not been previously described as an allograft reconstruction option for glenoid bone loss. Purpose: To evaluate distal radius fresh-frozen allograft (DRA) as a potential match for glenoid reconstruction. Study Design: Controlled laboratory study. Methods: Eighteen fresh-frozen human cadaveric specimens—including 6 shoulder, 6 wrist, and 6 tibia specimens—were used. The ROC and the graft length were measured in the superior-inferior (SI) plane. A 30% defect was created in all glenoid specimens, and both DTAs and DRAs were harvested to assess graft fit after fixation. Computed tomography analysis was used to assess bony ROC and bone mineral density (BMD). Results: The cadaveric specimens had a mean age of 77 years. The mean SI glenoid length was 39.7 mm compared with 36.8 mm for the DRA and 30 mm for the DTA. The ROC in the SI plane was 29 ± 5.3 mm for the glenoid, 37.8 ± 4.9 mm for the DRA, and 24 ± 3.7 mm for the DTA. In the AP plane, the ROC was 39.6 ± 6.6 mm for the glenoid, 30.4 ± 18.6 mm for the DRA, and 126.3 ± 9.5 mm for the DTA. On computed tomography analysis, the ROC in the SI plane was 30.4 ± 1.5 mm for the glenoid, 30.3 ± 5.6 mm for the DRA, and 24.5 ± 9.4 mm for the DTA. In the AP plane, the ROC was 30.8 ± 2 mm for the glenoid, 19.1 ± 2.3 mm for the DRA, and 46.7 ± 21.7 mm for the DTA. The BMD was 226.3 ± 79 Hounsfield units (HU) for the glenoid, 228.5 ± 94.7 HU for the DRA, 235 ± 96.2 HU for the coracoid process, and 235.1 ± 84.6 HU for the DTA. Conclusion: Compared with the DTA, the DRA had a greater mean graft length in the SI plane, providing utilization in cases of larger bony defects; the DRA has a more acute ROC in the AP plane (closer to that of the glenoid), providing a greater potential buttress to anterior humeral translation. Compared with currently utilized grafts, the DRA BMD was not significantly diminished. This study presents the DRA as a novel allograft reconstruction option in the setting of anterior glenoid bone loss; further biomechanical and clinical investigation is indicated.

Anterior Cruciate Ligament Allograft Reconstruction Augmented With a Reinforced, Bioinductive Collagen Scaffold in the Setting of Multiligamentous Knee Injury

The gold standard for surgical treatment of anterior cruciate ligament (ACL) injuries is reconstruction. There are a variety of graft options, from autograft to allograft, using bone–patellar tendon–bone (BTB), hamstrings, quadriceps, or Achilles, and, in the case of a multiligamentous knee injury (MLKI), allograft may be preferred to decrease operative time and graft harvest morbidity. The BioBrace (ConMed, New Haven, CT) is a bioinductive collagen scaffold designed to provide an environment for soft tissue remodeling with time zero biomechanical support and can be used to augment graft reconstructions in the case of concerns for allograft strength, healing, or width. The purpose of this Technical Note is to describe the technique for performing an ACL reconstruction with BioBrace-augmented allograft in the setting of a MLKI, with special consideration for 2 methods of graft preparation (BTB and soft tissue).

Limited recovery following acellular nerve allograft reconstruction in major peripheral nerve injuries

Recent studies suggest that acellular nerve allografts (ANA) have similar efficacy as nerve autografts in certain applications of nerve surgery. However, multiple studies also demonstrate the limitations of nerve allografts, resulting in poor patient outcomes. This submission discusses a recent case series of patients who failed allograft use with subsequent histologic analyses of these allografts. Recommendations on the treatment of nerve gaps are presented, drawing from our current understanding of allograft and autograft utility in reconstruction. Factors taken into account include recipient critical nerve function, existent nerve gap, and nerve diameter.

Pediatric parosteal osteosarcoma of the distal radius causing extensive erosive mass effect of the adjacent ulna: a case report

IntroductionParosteal osteosarcomas are low-grade bony malignancies that are treated primarily with surgical resection and reconstruction. This report discusses a unique case of a pediatric patient who presented with a parosteal osteosarcoma of the distal radius causing extensive erosive mass effect and growth disturbance of the adjacent ulna. Likely due to their slow-growing nonaggressive nature, parosteal osteosarcomas have not been previously described to abut adjacent bony structures through direct contact. The patient presented in a significantly delayed manner due to social circumstances, inadvertently revealing this novel behavior. This report reviews this rare case and describes the current understanding of this tumor.Case presentationThe patient is a 13-year-old male who presented with a parosteal osteosarcoma of his distal radius. He presented with a palpable wrist mass and wrist stiffness. He presented in a delayed manner with advanced local disease due to social factors. Imaging revealed an osseous radial mass that abutted the ulna and likely stunted its growth. The patient ultimately underwent complex resection and allograft reconstruction of both his distal radius and ulna. Intraoperative pathology was confirmed to have negative tumor margins. Allograft reconstruction of the radius and ulna was performed utilizing patient-specific custom cutting guides. At the 6-month postoperative visit, the patient had no recurrence of the mass, minimal pain, and had almost regained range of motion of the extremities. Clinical radiographs at the 6-month postoperative visit demonstrated allograft incorporation.ConclusionsA previously unreported case of pediatric parosteal osteosarcoma of the distal radius with erosion of the adjacent ulna through direct contact is presented. The challenges in and the importance of arriving at a definitive diagnosis in a timely manner for the proper treatment of this malignancy are emphasized.

Outcomes of proximal humeral reconstruction with cemented osteoarticular allograft in pediatric patients: a retrospective cohort study.

There is no agreement on the best choice of proximal humeral reconstruction following tumor resection in pediatric patients. We reviewed the functional outcomes, oncologic outcomes, and surgical complications in pediatric patients after proximal humeral reconstruction with cemented osteoarticular allograft. Eighteen patients aged 8-13 years who underwent proximal humeral osteoarticular allograft reconstruction following resection of primary bone sarcoma were included. The mean follow-up period was 88±31.7 months. At the last follow-up assessment, limb function was evaluated based on shoulder range of motion, Musculoskeletal Tumor Society score, and Toronto Extremity Salvage Score. Tumor recurrence and postoperative complications were extracted from the patients' medical records. Mean active forward flexion of the shoulder was 38°±18°. Mean active abduction was 48°±18°. Mean active external rotation was 23° ± 9°. The mean Musculoskeletal Tumor Society score was 73.4%±11.2%. The mean Toronto Extremity Salvage Score was 75.6%±12.9%. Local recurrence occurred in 1 patient. Metastasis developed after the operation in 2 additional patients. We recorded 6 postoperative complications in this series, including 1 superficial infection, 1 late-onset deep infection, 1 allograft fracture, 2 cases of nonunion, and 2 cases of shoulder instability. Two complications required allograft removal. In pediatric patients, reconstruction of the proximal humerus with cemented osteoarticular allograft results in acceptable oncologic and functional outcomes while the postoperative complication rate seems to be lower than that of other available techniques.

Analysis of Abduction Moment Arms after Rotator Cuff Tear and Acellular Dermal Matrix Allograft Reconstruction.

Biomechanical testing of abduction moment arms presents a useful method to assess the contribution of individual rotator cuff muscles to glenohumeral function. This study aimed to investigate the changes in abduction moment arms after a supraspinatus tear treated with Superior Capsule Reconstruction (SCR), Bursal Acromial Reconstruction (BAR), and a combined SCR-plus procedure, all with human dermal allograft. 7 fresh-frozen cadaveric specimens were tested in 6 conditions: (1) intact, (2) 50% supraspinatus tear (partial tear), (3) 100% supraspinatus tear, (4) SCR, (5) SCR+BAR, (6) BAR. In each condition, moment arms for the individual muscles of teres minor, subscapularis, and infraspinatus were calculated throughout 90º of abduction using Optotrak motion capture. ANOVA and post-hoc Tukey testing were performed to determine significance. In teres minor, the moment arms of the SCR (11.92mm), BAR (10.05mm), and SCR+BAR (11.87mm) conditions were greater than those in the intact (8.51mm, p=0.001, p=0.001, p=0.001, respectively), partial tear (9.09mm, p=0.001, p=0.128, p=0.001, respectively), and complete tear (8.75mm, p=0.001, p=0.011, p=0.001, respectively) conditions. Similarly in subscapularis, moment arms in the SCR (13.36mm), BAR (13.84mm), and SCR+BAR (13.53mm) conditions were greater than those in the intact condition (10.59mm, p=0.006, p=0.001, p=0.003, respectively) and partial tear condition (10.43mm, p=0.006, p=0.001, p=0.003, respectively). In teres minor, SCR (11.92mm) and SCR+BAR (11.87mm) were also found to have significantly increased moment arms compared to BAR (10.05mm, p=0.001, p=0.001, respectively). In Infraspinatus, BAR (13.77mm) was found to have a significantly decreased moment arm compared to the partial tear condition (15.78mm, p=0.026), with no other significant findings between conditions. These results suggest that the moment arm contributions from individual muscles comprising the rotator cuff can change after reconstruction to compensate for tears. SCR and SCR+BAR increase moment arms in teres minor and subscapularis, potentially allowing for increased abduction ability.

Giant Cell Tumor in the Proximal Femur of an Eight-Year-Old Boy: A Case Report

Background: Giant cell tumor (GCT) is a benign aggressive bone tumor that occurs mostly in young adult patients after puberty. The most common location is around the knee joint. Occurrence in pre-puberty pediatric patients is very rare and accounts for 1.8% to 10% of all known GCTs.
 Case Report: Here, we report an eight-year-old boy who complained of pain and loss of range of motion (ROM) in the right hip. Radiological and pathological studies revealed GCT of the femoral head with joint expansion. We treated the patient by wide resection and osteochondral allograft reconstruction.
 Conclusion: We believe this is the first reported case of GCT in the proximal femoral bone of pediatric patients, which is proven by pathology. Studying the current case may help tumor surgeons to become aware of this possibility.

Utilization Trends of Nerve Autograft Alternatives for the Reconstruction of Peripheral Nerve Defects.

Autologous nerve grafting is the time-honored reconstruction method for peripheral nerve gaps. However, it is associated with donor-site morbidities. A growing number of studies have demonstrated the effective use of decellularized nerve allograft and synthetic conduits, which are convenient options with no donor deficit. The specific aim of this study was to characterize changes in practice trends for peripheral nerve defect reconstruction. The authors queried the 2015 to 2020 Merative MarketScan Databases for patients who underwent nerve autograft, allograft, synthetic conduit, and/or vein graft reconstruction. Patient demographic data (ie, location, indication) and hospital characteristics (ie, facility, provider type) were recorded. Regression analysis identified changes in trends over the study period. A total of 4331 patients underwent one or more nerve gap reconstructive procedures over the study period. Since the introduction of allograft CPT code in 2018, segmented mixed effect longitudinal modeling revealed that allograft utilization significantly increased from 21.5% to 29.6% after 2018 ( P < 0.001), whereas nerve autograft use decreased from 18.6% to 15.8% and conduit use decreased from 60% to 54.7% ( P = 0.09 and P = 0.03, respectively). When stratifying autograft by size, use of autograft less than or equal to 4 cm significantly decreased from 10.6% to 7.7% after 2018 ( P = 0.03), and autograft greater than 4 cm did not. When stratifying by state, there is heterogeneity in utilization rates of each product. After creation of a designated allograft CPT code in 2018, there was an increase in allograft use with concomitant decrease in conduit and short length autograft use, suggesting that allograft replaced a portion of procedures used in short nerve gap reconstruction.

Immediate Inferior Alveolar Nerve Reconstruction With Ablative Mandibular Resection Results in Functional Sensory Recovery

Ablative mandibular resection with sacrifice of the inferior alveolar nerve (IAN) results in loss of sensation and decreased quality of life. The purpose of this study is to evaluate functional sensory recovery (FSR) of immediate IAN allograft reconstruction performed during ablative mandibular resection at 1year following surgery. This is a single-center retrospective cohort study that included consecutive subjects who underwent mandibular resection with IAN discontinuity and used a nerve allograft of ≥40mm. The primary predictor variable is the use of an immediate nerve allograft in mandibular reconstruction. The main outcome variable is FSR at 1year using the Medical Research Council Scale. Covariates include subject age, sex, specific pathology, nerve gap length, and development of neuropathic pain. Statistical analysis of comparison of neurosensory outcomes was measured by bivariate statistics, weighted values, repeated measures, analysis of variance, and McNemar test. The study sample was composed of 164 subjects, of whom 55 (33.5%) underwent nerve allograft reconstruction and 30 (18.3%) did not have nerve reconstruction. Seventy-nine subjects (48.2%) did not meet the inclusion criteria. In the entire nerve allograft group of 55 subjects, FSR was achieved in 80% at 1year; however, in benign disease alone, 31 of 33 (94%) achieved FSR at 1year. In the nonallograft group (all benign disease), only 2 of 30 (7%) achieved FSR at 1year. The significant covariates were age and pathology. Benign pathologic resections were 5.2 times more likely to achieve FSR than malignancies, and all subjects ≤ 18years of age achieved FSR. After adjusting for age, sex, pathology, nerve gap length, nerve allograft was significantly associated with achieving FSR at 1year (adjusted odds ratio=5.52, 95% confidence interval= (1.03, 29.51), P value=.045<.05). Immediate long-span IAN allograft reconstruction is effective in restoration of sensation with an overall 80% of subjects achieving FSR at 1year, while benign disease resulted in 94% FSR at 1year. Immediate IAN reconstruction should be considered with mandibular resection involving the IAN, especially for children and benign disease.

CORR Insights®: Allograft or Synthetic Mesh Extensor Mechanism Reconstruction After TKA Carries a High Risk of Infection, Revision, and Extensor Lag.

CORR Insights®: Allograft or Synthetic Mesh Extensor Mechanism Reconstruction After TKA Carries a High Risk of Infection, Revision, and Extensor Lag.

Limited Durability of Extensor Mechanism Reconstruction Following Total Knee Arthroplasty: Mesh and Allograft Show Equivalent Outcomes at Five-Year Follow-Up

BackgroundExtensor mechanism disruption is a challenging complication following total knee arthroplasty. The purpose of this study was to compare outcomes between patients who received mesh versus allograft extensor mechanism reconstruction. MethodsAll patients who underwent extensor mechanism reconstruction at a single institution were screened. Demographic and surgical variables were recorded, including technique (ie, synthetic mesh versus allograft reconstruction). Patients were assessed for preoperative and postoperative extensor lag, revision, and duration of follow-up. Analyses, including Kaplan-Meier survivorships, were performed to compare mesh to allograft reconstruction. In total, 50 extensor mechanism reconstructions (30 mesh and 20 allograft) were conducted between January 1st, 2001, and December 31st, 2022. ResultsThere were no differences between the cohorts with respect to revision (26.7 [8 of 30] versus 35.0% [7 of 20], P = .680) or failure defined as above knee amputation or fusion (6.7 [2 of 30] versus 5.0% [1 of 20], P = .808). There were also no differences in time to reoperation (average 27 months [range, 6.7 to 58.8] versus 29 months [range, 1.2 to 84.9], P = .910) or in postoperative extensor lag among patients who did not undergo a reoperation (13 [0 to 50] versus 11° [0 to 30], P = .921). The estimated 5-year Kaplan-Meier survival with extensor mechanism revision as the endpoint was similar between the 2 groups (52.1, 95% confidence interval [CI] = 25.4 to 73.3 versus 55.0%, 95% CI = 23.0 to 78.4%, P = .990). ConclusionsThe purpose of this study was to present the findings of a large cohort of patients who required extensor mechanism reconstruction. Regardless of the reconstruction type, the 5-year outcomes of patients requiring extensor mechanism reconstruction are suboptimal.

Does Immediate Long-Span Nerve Allograft Reconstruction Affect the Incidence of Chronic Postsurgical and Neuropathic Pain in the Reconstructed Mandible Following Resection for Benign and Malignant Disease

Peripheral nerve injury can lead to chronic postsurgical pain (CPSP) and neuropathic pain following major surgery. Determine in patients undergoing ablative mandibular operations with transection of the trigeminal nerve: do those who undergo immediate repair, when compared to those whose nerves are not repaired, have a decreased or increased risk for CPSP or post-traumatic trigeminal neuropathic pain (PTTNp)? A multisite, retrospective cohort of patients who underwent resection of the mandible for benign or malignant disease with either no repair or immediate repair of the intentionally transected trigeminal nerve with a long-span nerve allograft were analyzed for the presence or absence of CPSP and PTTNp at 6months. The primary predictor was the immediate repair or no repair of the trigeminal nerve. The primary outcome was the presence or absence of CPSP and PTTNp at 6months postsurgery. There were 13 covariate variables, including age, sex, ethnicity, nerve injury, type of PTTNp, malignant or benign pathology and subtypes of each, use of radiation or chemotherapy, treatment of transected nerve end, longest follow-up time, pain scale, and onset of pain. Two-tailed Student's t test and Welch's t test were performed on mean scores and post hoc logistics and linear regression modeling were performed when indicated. The confidence level for statistical significance was P value <.05. There were 103 and 94 subjects in the immediate and no-repair groups, respectively. The incidence of CPSP in the no-repair group was 22.3% and PTTNp was 2.12%, while there was 3.8% CPSP and 0% PTTNp in the repair group, which was statistically significant (P= <.001). Logistic regression modeling showed a statistically significant inverse relationship between the immediate repair and the incidence of CPSP/PTTNp with an odds ratio of 0.43, 95% confidence interval 0.18 to 1.01, P=.05. Greater age, malignant pathology, and chemo/radiation treatments were covariates found more frequently in the no repair group. Immediate repair of an intentionally transected trigeminal nerve with a long-span nerve allograft during resection of the mandible for both benign and malignant disease appears to reduce CPSP and possibly eliminate the development of PTTNp.

Management of limb length discrepancy after bone sarcoma resection about the knee in the skeletally immature.

Patients with bone sarcomas increasingly choose limb salvage. This can lead to issues with limb length discrepancy (LLD) for the skeletally immature. We synthesize management options into an algorithm and report our results. Patients with bone sarcomas involving any location from the femoral diaphysis to the tibial diaphysis 12 years or younger were reviewed. Our clinical pathway prescribed patients with metadiaphyseal lesions to intercalary allograft reconstruction, epiphyseal lesions and less than 5 cm expected LLD to osteoarticular allograft and patients with more than 5 cm expected LLD to extendable prosthesis. Twenty patients met inclusion criteria: 11 with osteoarticular allografts, 5 with extendable prostheses and 4 with intercalary allografts; median age 11.5 years; median follow-up 8.2 years; and final median LLD 1.6 cm. Five patients had contralateral epiphysiodesis, two patients underwent contralateral femoral shortening and a median of 6 (range 4-8) lengthenings were performed for extendable prostheses. Four patients had residual LLD over 3 cm. There were 13 revisions in 8 patients and 2 amputations. Limb-salvage in paediatric bone sarcoma of the knee can be managed with multiple techniques producing satisfactory results in regards to LLD. Careful pre-operative planning and shared decision making is a requisite given the high rate of secondary procedures for both LLD and reconstructive failures. Level of evidence: Level III Retrospective Comparative Study.

Allograft or Synthetic Mesh Extensor Mechanism Reconstruction After TKA Carries a High Risk of Infection, Revision, and Extensor Lag.

Extensor mechanism disruption is a devastating complication after TKA. Extensor mechanism reconstruction can be performed using an allograft or synthetic mesh. Recent studies have disagreed about the durability of these reconstructions. Evaluating a larger series of reconstructions that use current popular techniques and principles provides information to guide patient and surgeon expectations while bringing to light the potential fate of patients who experience an infection postoperatively. (1) What was the 5-year survival free of repeat revision surgery or persistent extensor lag of more than 30° after allograft or synthetic mesh reconstruction of extensor mechanism disruptions after TKA, and did this differ between techniques? (2) What was the 5-year survival free of infection after allograft or mesh reconstruction, and what proportion of those patients experienced a secondary severe complication (arthrodesis or amputation)? Between April 2008 and December 2020, 123 patients underwent extensor mechanism reconstruction after TKA at one center. Of those, 37% (45) were lost to follow-up before 2 years, had not been seen in the past 5 years, did not reach a study endpoint (repeat revision or extensor lag > 30°) before that time, or underwent primary repair and thus could not be analyzed, leaving 63% (78) for analysis here. During the study period, we considered extensor mechanism surgery when acute or chronic disruption of the patellar or quadriceps tendon was present or there was a fracture of the patella resulting in extensor lag. The decision to use either mesh or an allograft largely depended on surgeon experience and familiarity with either technique. We collected patient demographics, operative details (location of disruption and presence of a hinged prosthesis), subsequent periprosthetic joint infection (PJI), and postoperative SF-12 and Knee Injury and Osteoarthritis Outcome Score, Joint Replacement, scores. We used Kaplan-Meier survivorship analysis, with endpoints of extensor lag more than 30° or revision of the reconstruction and PJI. The mean follow-up duration was 5.3 ± 3.2 years. Survivorship free from revision or recurrent extensor lag was 54% (95% CI 44% to 66%) at 5 years. There was no difference between those undergoing reconstruction with allografts and those with mesh in terms of survivorship free from those endpoints at that timepoint (52% [95% CI 40% to 68%] versus 57% [95 CI% 41 to 78%]; p = 0.99). Survivorship free from PJI was 81% (95% CI 73% to 90%) at 2 years. There was no difference between those with allografts and those with mesh in terms of survivorship free from PJI at that timepoint (79% [95% CI 69% to 92%] versus 83% [95% CI 71% to 98%]; p = 0.75). Of the 17 patients who experienced PJI, four ultimately underwent arthrodesis and three more underwent transfemoral amputation. Allograft and synthetic mesh reconstructions commonly left patients with persistent limb dysfunction, while several patients had PJI and some underwent salvage procedures. Although improvements have been made with regard to treating extensor mechanism disruptions, patients and surgeons should be well aware of the potential adverse outcomes when determining management and use these findings to conduct risk-benefit analyses. There is a need for future studies to identify protocols that improve the durability of reconstructions and to determine whether interventions such as prolonged prophylactic antibiotic therapy have a role in minimizing the risk of PJI. Level III, therapeutic study.

Allograft Use in Hand Surgery – ‘Off the Shelf’ Tendon Reconstruction: A Scoping Review

Introduction: Tendon grafting is standard for treating tendon defects. Allografts are popular in cruciate ligament reconstruction but not yet in upper limb tendon reconstruction. A scoping review was conducted to map the existing practice of allograft use in hand surgery for tendon reconstruction and identify gaps in knowledge for future research. Methods: Two independent reviewers searched MEDLINE and SCOPUS databases for studies on upper limb tendon reconstruction using tendon allografts until June 2022. Eligible studies included controlled randomised clinical trials, cohort, case-control, cross-sectional, or case report and series studies conducted in English and enrolling patients who underwent tendon allograft reconstruction in the upper limb. Screening for eligibility was done by both reviewers, who reached a consensus through discussion, with no exclusion based on poor methodological quality. Data charting included study title, patients’ demographics and outcomes, complications, and follow-up period. Results: The database search found 6 eligible articles with a total of 116 patients and 148 allografts used for reconstruction. Of the studies that looked at functional outcomes, 72.9% of patients had ‘good’ or ‘fair’ results, while 25.8% were classed as ‘poor’. All of the patients assessed for subjective outcomes were at least partially/fairly satisfied with the allograft. Conclusion: This scoping review has indicated that the utilisation of tendon allografts in the upper limb can potentially be a promising approach for tendon reconstruction, especially in cases of severe trauma or salvage. However, further research is needed to comprehensively assess efficacy, long-term outcomes, complications, postoperative rehabilitation protocols, and comparative effectiveness against autograft tendon reconstruction.

Dynamic Seeding versus Microinjection of Adipose-Derived Mesenchymal Stem Cells to Acellular Nerve Allograft Reconstructions.

Functional recovery after acellular nerve allograft (ANA) reconstruction remains inferior to that after autologous nerve grafting, but improved outcomes have been demonstrated with the addition of adipose-derived mesenchymal stem cells (MSCs). Controversy exists regarding the optimal cell-delivery method to enhance ANA reconstructions. The authors investigated the functional recovery of ANAs after dynamic seeding versus microinjection of MSCs. Forty Lewis rats underwent reconstruction of a 10-mm sciatic nerve defect. Animals were divided into 4 groups: reversed autograft, ANA alone, dynamically seeded ANA, or ANA injected with MSCs. During the survival period, ultrasound measurements of the tibialis anterior muscle cross-sectional area were performed. At 12 weeks, functional recovery was evaluated using measurements of ankle contracture, compound muscle action potential, maximum isometric tetanic force, muscle mass, histomorphometry, and immunofluorescence. The dynamic seeding and microinjection groups demonstrated higher cross-sectional tibialis anterior muscle area recovery than autografts and ANAs alone at week 8 and weeks 4 and 8, respectively. The ankle contracture and compound muscle action potential amplitude recovery were superior in autografts and both seeding methods compared with ANAs alone. The microinjection group demonstrated significantly higher isometric tetanic force, muscle mass, and number of axons compared with ANAs alone. Both seeding methods showed higher CD34 densities compared with ANAs alone. No significant differences between dynamic seeding and microinjection were observed in functional or histologic outcomes. The addition of MSCs to ANAs demonstrated earlier motor regeneration compared with autografts and ANAs alone. Both seeding methods improved functional outcomes in the rat sciatic nerve defect model.

Biological reconstruction of bone defect after resection of malignant bone tumor by allograft: a single-center retrospective cohort study

BackgroundAllograft 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.Materials and methodsThirty-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.ResultsIntercalary 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.ConclusionsAllograft 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.

COST-UTILITY OF VARIOUS BIOLOGIC VERSUS ENDOPROSTHETIC RECONSTRUCTION FOR PRIMARY BONE SARCOMA OF THE HUMERUS

Background: The development of bone sarcoma treatment has resulted in a higher survival rate of patients including the developed surgical treatment called limb salvage surgery. Reconstructive surgery plays a vital role among patients and their quality of life after treatment. However, cost-effectiveness is another crucial factor in choosing a treatment method.&#x0D; Methods: Eighteen patients with osteosarcoma were recruited in this study. All were treated using limb salvage surgery. The data were collected using the utility coefficient from the EQ-5D-5L Health Questionnaire. The patient’s medical cost was obtained from Phramongkutklao Hospital, and all data were calculated for cost-effectiveness using the cost-utility analysis.&#x0D; Results: Endoprosthesis reconstruction exhibited the highest utility value of 0.85 QALY and the lowest treatment complications. Nevertheless, the most increased cost was an average of 238,432.34 THB. In terms of cost, the recycled autograft showed the lowest treatment cost at an average of 60,774.61 THB. However, the complication of this method was quite severe, with a 50% recurrence rate. Allograft reconstruction was the most cost-effective method with a lower cost than endoprosthesis reconstruction (61,341.40 THB), despite having a lower utility of 0.49 QALY.&#x0D; Conclusion: This study reported that endoprosthesis reconstruction resulted in more optimistic patient well-being but still indicated high cost. Using one-way sensitivity analysis, the QALY gain was only 16.9% of Thai per capita. When the cost of endoprosthesis reconstruction was reduced by only 15%, it could replace allograft reconstruction. In addition, an increase of the QALY, gaining only 20% of the average Thai per capita, would be cost-effective when the expense of endoprosthesis reconstruction was reduced by 4%.

Poster 252: BMAC Augmentation of Allograft Anterior Cruciate Ligament Reconstruction Improves Patient Reported Outcomes in the Presence of Intra-articular Pathology

Objectives: A randomized control trial demonstrated evidence of earlier graft remodeling and improved 9-month International Knee Documentation Committee (IKDC) scores when anterior cruciate ligament reconstruction (ACLR) with bone-tendon-bone allograft was augmented with an intra-graft injection of bone marrow aspirate concentrate (BMAC). While these results are promising, the mechanism by which BMAC may affect patient reported outcome measures (PROMs) following ACLR is unclear. Methods: This was a sub-analysis of patients enrolled to date in an IRB-approved, double-blinded, randomized control trial comparing patients undergoing ACLR with BTB allograft ± BMAC. Only patients who had completed at least 9 months follow-up were included. Patients were stratified by 1) treatment arm (BMAC versus control) and 2) presence of concurrent meniscus or cartilage pathology, as noted on diagnostic arthroscopy). The primary outcome was the Tegner activity scale and International Knee Documentation Committee (IKDC) at 9 months. A secondary sub-analysis assessed differences in MRI characteristics (signal intensity ratio [SIR], graft volume) by group. Results: The final study cohort included 44 BMAC patients – 19 (43%) without and 25 (57%) with concurrent cartilage or meniscus pathology – and 39 control group patients - 16 (41%) without and 23 (59%) with concurrent cartilage or meniscus pathology. 24 patients in the BMAC group had a meniscus lesion, 13 of which were treated via meniscectomy (54%) and 11 by meniscus repair (46%). By comparison, 21 patients in the control group had a meniscus lesion (P=0.57), 11 who were treated with meniscectomy (52%, P=0.88) and 11 who had a meniscus repair (P=1.00). 5 patients with BMAC (20%) and 6 control patients (25%) had a cartilage injury noted intraoperatively (P=0.94); chondroplasty was performed in 2 patients in the BMAC group (8.0%) and 4 patients in the control group (16.7%). Tegner score at 9 months did not differ by BMAC treatment or presence of concurrent meniscus/cartilage pathology (P=0.816). If a patient had a concurrent meniscus and/or cartilage lesion, the group treated with BMAC had a greater mean IKDC at 9 months (81.7 [SD=10.2] vs. 74.3 [SD=14.6], P=0.039). If a patient had no concurrent pathology, there was no difference in IKDC scores by treatment group (P=0.80). Change in Tegner (P=0.99) and IKDC (P=0.31) did not differ by groups. At 3 months, patients with BMAC and concurrent pathology had the highest mean SIR in the inferior 1/3 of the graft (3.00), followed by patients with BMAC but no concurrent pathology (2.60), controls without concurrent pathology (1.95), and controls with concurrent pathology (1.83, P=0.041). There were no significant differences in SIR at 9 months or graft volume, in this comparative cohort study. Conclusions: Amongst patients with concurrent meniscus and/or cartilage lesions, patients with BMAC had an 8-point higher mean IKDC score than controls at 9 months postoperatively. However, there was no difference in mean IKDC score between BMAC and control groups if no concurrent pathology was present. Thus, improved IKDC amongst patients with BMAC may be mediated by improved healing of repaired tissue or through an undefined anti-inflammatory or nociceptive pathway. Further investigation will be required to delineate a physiologic mechanism of action associated with BMAC during the recovery process when utilized at the time of ACL allograft reconstruction. [Table: see text][Table: see text][Table: see text]