Allograft Anterior Cruciate Ligament Research Articles

GRAFTS COMPARISON BETWEEN QUADRICEPS TENDON AUTOGRAFT VS. ALLOGRAFT FOR ANTERIOR CRUCIATE LIGAMENT REVISIOON RECONSTRUCTION: A LITERATURE REVIEW

Introduction: Anterior cruciate ligament (ACL) reconstruction is one of the most common orthopaedic surgeries performed on active people in the world. One of the most important surgical decisions is graft type for use in the reconstruction. Recently, the quadriceps tendon has gained popularity for use as a graft source for ACL reconstruction. The graft choice is broadly between an autograft or allograft. This review aims to understand the current concepts in graft comparison between quadriceps tendon autograft vs. allograft for anterior cruciate ligament revision reconstruction. Methods: This literature review study was reported following the preferred reporting items for systematic reviews and adhered to a structured review protocol. The author searched the PubMed, ScienceDirect, and British Medical Journal databases. The authors comparing selected publications reporting patient outcomes with all types of reviews or descriptions of ACL revision reconstruction and its graft being used or other related subjects. Published in English is included. The author then formulates a synthesis to support the previously determined research objectives. Results: ACL reconstruction with partial thickness soft tissue quadriceps tendon graft is a reliable option. Where there are differences in the failure rates of ACL reconstructions between allografts and autografts, these can mostly be explained by irradiated grafts. Giving sufficient radiation to achieve sterility will likely weaken grafts and make them more likely to fail; therefore, irradiating grafts is not recommended. The evidence shows no significant differences in clinical effectiveness between autografts and non-irradiated allografts. Failure rates with both grafts are now low. Discussion: The primary goals of rehabilitation after ACL reconstruction do not vary considerably based on graft type and emphasize: (1) restoration of the full range of motion, (2) normalization of quadriceps strength, (3) improvement of overall lower extremity muscle strength, and (4) re-training of movement patterns to return to pre-injury sports participation while decreasing injury risk. Achieving full motion and quadriceps strength contributes to a rapid return to normal weight bearing, gait, and activities of daily living. In the setting of revision ACL reconstruction, there are various considerations regarding graft choice due to tunnel size or position, previous usage of other grafts, and reconstructions in the other leg, which may mean that allografts would be preferred to autografts. The other population not covered sufficiently in the literature is the elite sprinting athlete, where autograft choices may be influenced by the effect of graft harvesting on their sport. However, in most cases, allograft ACL reconstruction with non-irradiated grafts is as safe but more expensive than autograft ACL reconstruction, which is preferred as it is more cost-effective. Conclusion: There is little difference in the results of ACL reconstruction with autografts or non-irradiated allografts, with any advantage being with autografts. The cost is higher with allografts. So if autografts are available, allografts are not cost-effective.

Tobramycin and Vancomycin in an In Vitro Model of Anterior Cruciate Ligament Allograft Decontamination

Background: Approximately 100,000 anterior cruciate ligament (ACL) reconstructions (ACLRs) occur annually in the United States, and postoperative surgical-site infection is a relatively rare but devastating complication, often leading to graft failure or septic arthritis of the knee, necessitating repeat surgery. Wrapping allografts in vancomycin-soaked gauze has been adopted as a common sterilization technique in the operating room to reduce surgical-site infection; however, identifying effective alternatives to vancomycin has not been extensively pursued. Hypothesis: Tobramycin would be as effective as vancomycin in reducing the concentrations of Staphylococcus epidermidis bacteria on tendon allografts. Study Design: Controlled laboratory study. Methods: S. epidermidis strain ATCC 12228 was inoculated onto the human cadaveric gracilis tendon. The tendons were wrapped in sterile gauze saturated with tobramycin or vancomycin at various experimental concentrations. Bacteria remaining on the tendon were dislodged, serially diluted, and plated for colony counting. Statistical analysis was performed utilizing 2-way analysis of variance testing. Results were considered statistically significant when P < .05. Results: Vancomycin (P = .0001) and tobramycin (P < .0001) reduced bacterial concentration. Tobramycin was found to produce a statistically significant reduction in bacterial concentration at concentrations as low as 0.1 mg/mL (P < .0001 and P = .01 at 10 and 20 minutes), while vancomycin produced a statistically significant reduction at a concentration as low as 2.5 mg/mL (P < .0001 at both 10 and 20 minutes). Conclusion: This study demonstrates that tobramycin is as effective as vancomycin in bacterial concentration reduction but can achieve this reduction level at lower doses. Further studies clarifying the biomechanical and cytotoxic effects of tobramycin on tendon tissue are indicated to solidify its use as a clinical alternative to vancomycin in ACLR. Clinical Relevance: These results will begin establishing tobramycin as an alternative to vancomycin in ACL graft decontamination. Because of relatively frequent shortages of vancomycin, establishing tobramycin as an alternative agent is a useful option for the orthopaedic surgeon.

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).

Recurrent cyclops lesion after primary anterior cruciate ligament reconstruction using bone tendon bone allograft: A case report

BACKGROUND Cyclops lesions are a known complication of anterior cruciate ligament (ACL) reconstruction, with symptomatic cyclops syndrome occurring in up to 11% of surgeries. Recurrent cyclops lesions have been rarely documented; this case study documents the successful treatment of a recurrent cyclops lesion. CASE SUMMARY A 28-year-old female presented following a non-contact injury to the right knee. Workup and clinical exam revealed an ACL tear, and arthroscopic reconstruction was performed. Two years later a cyclops lesion was discovered and removed via arthroscopic synovectomy. Seven months postoperatively, the patient presented with pain, stiffness, and difficulty achieving terminal extension. A smaller recurrent cyclops lesion was diagnosed, and a repeat synovectomy was performed. The patient recovered fully. CONCLUSION To the best of our knowledge, this is the first documented case of recurrent cyclops lesion after bone-patellar tendon-bone allograft ACL reconstruction presenting as cyclops syndrome.

Short-Term Evaluation of Bone-ACL-Bone Complex Allograft in ACL Reconstruction in a Rabbit Model.

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.

Allograft Anterior Cruciate Ligament Reconstruction in Adolescent Patients May Result in Acceptable Graft Failure Rate in Non-pivoting Sports Athletes.

Allograft Anterior Cruciate Ligament Reconstruction in Adolescent Patients May Result in Acceptable Graft Failure Rate in Non-pivoting Sports Athletes.

Revision Rates After Primary Allograft ACL Reconstruction by Allograft Tissue Type in Older Patients.

While there is extensive literature on the use of allograft versus autograft in anterior cruciate ligament (ACL) reconstruction, there is limited clinical evidence to guide the surgeon in choice of allograft tissue type. To assess the revision rate after primary ACL reconstruction with allograft and to compare revision rates based on allograft tissue type and characteristics. Cohort study; Level of evidence, 3. Patients who underwent primary allograft ACL reconstructions at a single academic institution between 2015 and 2019 and who had minimum 2-year follow-up were included. Exclusion criteria were missing surgical or allograft tissue type data. Demographics, operative details, and subsequent surgical procedures were collected. Allograft details included graft tissue type (Achilles, bone-patellar tendon-bone [BTB], tibialis anterior or posterior, semitendinosus, unspecified soft tissue), allograft category (all-soft tissue vs bone block), donor age, irradiation duration and intensity, and chemical cleansing process. Revision rates were calculated and compared by allograft characteristics. Included were 418 patients (age, 39 ± 12 years; body mass index, 30 ± 9 kg/m2). The revision rate was 3% (11/418) at a mean follow-up of 4.9 ± 1.4 years. There were no differences in revision rate according to allograft tissue type across Achilles tendon (3%; 3/95), BTB (5%; 3/58), tibialis anterior or posterior (3%; 5/162), semitendinosus (0%; 0/46), or unspecified soft tissue (0%; 0/57) (P = .35). There was no difference in revision rate between all-soft tissue versus bone block allograft (6/283 [2%] vs 5/135 [4%], respectively; P = .34). Of the 51% of grafts with irradiation data, all grafts were irradiated, with levels varying from 1.5 to 2.7 Mrad and 82% of grafts having levels of <2.0 Mrad. There was no difference in revision rate between the low-dose and medium-to high-dose irradiation cohorts (4% vs 6%, respectively; P = .64). Similarly low (0%-6%) revision rates after primary ACL reconstruction were seen regardless of allograft tissue type, bone block versus all-soft tissue allograft, and sterilization technique in 418 patients with mean age of 39 years. Surgeons may consider appropriately processed allograft tissue with or without bone block when indicating ACL reconstruction in older patients.

Bone-Patellar Tendon-Bone Allograft Preparation Technique for Anterior Cruciate Ligament Reconstruction

Background: Allograft anterior cruciate ligament (ACL) reconstruction, while it may have a higher failure rate in younger and more active populations, continues to serve as a viable graft option for the appropriately indicated patient. Efficient bone-patellar tendon-bone (BTB) allograft preparation is beneficial to reduce operating time and ensure optimal reconstruction with bony fixation. Indications: ACL reconstruction with BTB allograft is indicated for skeletally mature and older patients, patients who are less active and have fewer physical demands, patients who have had previously harvested autograft, circumstances where an autograft harvest is inadequate, patients with multiligament knee injuries, and patients who prefer allograft use. Technique Description: The central third of the BTB allograft is harvested, aiming for a graft diameter of 10 mm along the tendon. The tibial bone plug is first cut to a length of 25 to 30 mm and width of 10 mm with the saw at a 70° angle to the bone. The patellar bone plug is cut to a length of 25 mm and width of 10 mm with the saw at a 45° angle to the bone. The bone plugs are mobilized, and soft tissue is dissected to free the graft. The graft is trimmed until it fits through a 10-mm sizer on each side. A single hole is created with a k-wire in the patellar bone plug, and a #5 Ethibond suture is passed. On the tibial bone plug, 2 holes are made perpendicular to one another, and a #2 Fiberwire suture is passed through each of these holes. These sutures allow for facilitated graft passage and tensioning. Once the graft is affixed with interference screws, the graft is arthroscopically evaluated throughout range of motion. Results: ACL reconstruction with BTB allograft provides high success rates in appropriately selected patients. Data demonstrate more optimal mechanical properties by harvesting the central third of the allograft tendon in younger donors. Non-irradiated and less chemically processed grafts are also preferred to optimize biomechanical properties. Discussion/Conclusion: Bone-patellar tendon-bone allograft with 2 bone plugs offers a reliable alternative to other allografts or autografts. Preparing the allograft in a fashion similar to an autograft harvest may increase familiarity with techniques and facilitate surgical efficiency and graft passage. 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.

Allograft Anterior Cruciate Ligament Reconstruction in Adolescent Patients May Result in Acceptable Graft Failure Rate in Nonpivoting Sports Athletes.

Studies have demonstrated that pediatric patients have an increased risk of failure with allograft anterior cruciate ligament reconstruction (ACLR); however, there is no study investigating whether allograft ACLR may be safe in older adolescent patients who are not returning to competitive pivoting sports (ie, low risk). The purpose of this study was to assess outcomes for low-risk older adolescents selected for allograft ACLR. We performed a retrospective chart review of patients younger than 18 years who received a bone-patellar-tendon-bone allograft or autograft ACLR by a single orthopaedic surgeon from 2012 to 2020. Patients were offered allograft ACLR if they did not intend to return to pivoting sports for 1 year. The autograft cohort was matched 1:1 based on age, sex, and follow-up. Patients were excluded for skeletal immaturity, multiligamentous injury, prior ipsilateral ACLR, or concomitant realignment procedure. Patients were contacted to obtain patient-reported outcomes at ≥2 years follow-up, including single assessment numerical evaluation, surgery satisfaction, pain scores, Tegner Activity Scale, and the Lysholm Knee Scoring Scale. Parametric and nonparametric tests were used as appropriate. Of the 68 allografts, 40 (59%) met inclusion and 28 (70%) were contacted. Among the 456 autografts, 40 (8.7%) were matched and 26 (65%) were contacted. Two allograft patients (2/40; 5%) failed at a median (interquartile range) follow-up of 36 (12, 60) months. There were 0/40 failures in the autograft cohort and 13/456 (2.9%) among the overall autografts; neither were significantly different from the allograft failure rate (both P > 0.05). Two (5.0%) patients in the autograft cohort required manipulation under anesthesia and arthroscopic lysis of adhesions. There were no significant differences between cohorts for single assessment numerical evaluation, Lysholm, Tegner, pain, and satisfaction scores (all P > 0.05). Although ACL allograft failure rates remain nearly two times higher than autograft failure rates in older adolescents, our study suggests that careful patient selection can potentially bring this failure rate down to an acceptable level. Level III; retrospective matched cohort study.

Low-Volume Surgeons Use Allograft in Younger Patients and Show Greater Rates of Revision Following Primary Allograft Anterior Cruciate Ligament Reconstruction Compared With High-Volume Surgeons

To determine whether surgeon volume affects revision rate following primary anterior cruciate ligament reconstruction (ACLR) with allograft and to determine whether surgeon volume impacts allograft tissue type used. All patients aged 14 years or older who underwent primary allograft ACLR at a large hospital system between January 2015 to December 2019 with minimum 2-year follow-up were included. Patients with double-bundle ACLR, multiligament reconstruction, and absent allograft type data were excluded. Surgeon volume was categorized as 35 or more ACLR/year for high-volume surgeons and less than 35 ACLR/year for low-volume surgeons. Revision was defined as subsequent ipsilateral ACLR. Patient characteristics, operative details, allograft type, and revision ACLR rates were retrospectively collected. Revision rate and allograft type were analyzed based on surgeon volume. A total of 457 primary allograft ACLR cases (mean age: 38.8 ± 12.3 years) were included. Low-volume surgeons experienced greater revision rates (10% vs 5%, P= .04) and used allograft in a younger population (37.6 vs 40.0 years old, P= .03) than high-volume surgeons. Subgroup analysis of the total cohort identified a significantly increased failure rate in patients <25 years old compared with ≥25 years old (30% vs 4%, P < .001). Allograft type selection varied significantly between surgeon volume groups, with low-volume surgeons using more bone-patellar tendon-bone (P < .001) and less semitendinosus allograft (P= .01) than high-volume surgeons. No differences in revision rate were observed based on allograft type (P= .71). There was a greater revision rate following primary allograft ACLR among low-volume surgeons compared with high-volume surgeons. Low-volume surgeons also used allograft in a younger population than did high-volume surgeons. Level III, retrospective comparative prognostic trial.

Allograft Anterior Cruciate Ligament Reconstruction Fails at a Greater Rate in Patients Younger Than 34 Years

To characterize the secondary anterior cruciate ligament (ACL) injury rates after primary allograft anterior cruciate ligament reconstruction (ACLR) and to identify the age cut-score at which the risk of allograft failure decreases. All patients who underwent primary ACLR within a single orthopaedic department between January 2005 and April 2020 were contacted at a minimum of 2 years post-ACLR to complete a survey regarding complications experienced post-surgery, activity level, and perceptions of knee health. Patients were excluded for incidence of previous ACLR (ipsilateral or contralateral) and/or age younger than 14 years. Relative proportions were calculated, binary regression analysis was performed, and receiver operating characteristic analysis was used to identify the threshold age for maximal sensitivity and specificity to predict high risk of allograft failure, defined as undergoing revision ACLR. Of the 939 surveys completed, 398 patients underwent primary allograft ACLR (mean age 39.5years; range 16.0-66.1 years; 54.3% female). The secondary ACL injury rate was 11.6% (5.8% ipsilateral revision ACLR, 5.8% contralateral ACL injury). Male and female patients had similar revision (5.5% male, 6.0% female, P= .82) and contralateral ACL injury rates (6.6% male, 5.1% female, P= .52). Receiver operating characteristic analysis indicated that age ≤34 years was threshold for differentiating high risk of allograft failure (area under the curve 0.65, 95% confidence interval 0.55-0.76; P= .014). Patients aged ≤34 years had a greater secondary injury rate than patients >34 years (20.4% (10.2% revision ACLR, 10.2% contralateral ACL injury) versus 6.9% (3.5% revision ACLR, 3.5% contralateral ACL injury; P < .001). Binary regression analysis demonstrated that decreasing age was associated with increased risk of graft failure (χ2= 7.9, P= .02.). Allograft ACLR showed similar failure rates between sexes but displayed suboptimal graft failure outcomes in younger and active patients. By age 34 years, the increased revision risk for younger patients diminished. Level IV, therapeutic case series.

A randomised controlled study for the comparison of functional outcome of femoral tunnel fixation devices, aperture fixation by screw vs suspensory fixation by endo-button in arthroscopic anterior cruciate ligament reconstruction

: The goal of this study was to compare suspensory and aperture fixation methods for restoring soft tissue allografts in the anterior cruciate ligament (ACL).: 30 patients were chosen and randomly allocated to one of two experimental groups, suspensory fixation or aperture fixation, following the completion of a prospective analysis, permission from the institutional review board, and patient agreement. All of the patients underwent ACL reconstruction surgery using soft tissue allografts made of hamstring tendon. The procedures were either (1) femoral and tibial fixation with a femoral cannulated interference screw and a tibial cannulated interference screw (aperture) or (2) femoral cortical buttons (suspensory) and a tibial cannulated interference screw. The subjective anterior drawer test analysis and changes in the International Knee Documentation Committee knee examination rating were employed as end measures.: All of the patients who had received treatment (100%) had successfully completed a clinical assessment at the 1-month, 4-month, 8-month, and 12-month follow-ups. Out of the 30 patients who were included, 15 (50%) underwent suspensory fixation treatment and the other 15 (50%) underwent aperture fixation treatment. The primary outcome measure—AP stability at 25 degrees of knee flexion—did not differ across groups at a 12-month follow-up. Also, at the 1-month and 4-month evaluations, secondary data revealed a statistically significant difference between the groups.: Our data showed no meaningful differences in knee AP stability or other outcomes between ACL allograft reconstruction using aperture fixation and ACL allograft reconstruction utilising suspensory fixation at the 12-month mark, while aperture fixation performed better at the first and fourth months. One of our main outcome measures was the grading of knee anteroposterior (AP) stability (clinical judgments).: Level II, lesser-quality randomised controlled trial with a follow-up of 1 year.

Subjective Outcomes After Allograft Reconstruction and Nonoperative Treatment of Anterior Cruciate Ligament Ruptures Are Similar in Patients Aged 40 Years and Older: A 2:1 Propensity Score–Matched Analysis

To compare subjective outcomes and rates of subsequent operations for patients aged 40 years and older with anterior cruciate ligament (ACL) ruptures who elected nonoperative management or allograft ACL reconstruction (ACLR). This was a retrospective study comparing 2-year minimum results of nonoperative treatment and primary allograft ACLR among patients aged 40 years and older presenting to a single institution between the years 2005 and 2016. Patients who elected nonoperative management were 2:1 propensity score (PS)-matched to patients who elected ACLR based on age, sex, body mass index, sports-related mechanism of injury, Outerbridge grade III or IV chondral lesions, and medial or lateral meniscus tears. Univariate analysis was performed to compare subjective outcome measures of International Knee Documentation Committee and Marx activity level scores, subsequent operations, and satisfaction rates. After 2:1 PS matching, 40 ACLR and 20 nonoperative patients with mean ages of 52.2 years and 54.5 years, respectively, were included with a mean follow-up of 5.7 years (SD 2.1 years, range 2.3-10.6 years). There were no significant differences between the groups in any of the matching variables. There were no significant differences in International Knee Documentation Committee scores (81.9 ± 14.1, CI 77.4-86.5 vs 84.3 ± 12.8, CI 78.3-90.3, P= .53), Marx activity level scores (5.8 ± 4.8, CI 4.2-7.3 vs 5.7 ± 5.1, CI 3.3-8.1, P= .96), or satisfaction rates (100% vs 90%, P= .11) between the ACLR and nonoperative groups. Four (10%) patients who underwent ACLR sustained a graft treated with revision ACLR. 7 (17.5%) ACLR and 0 nonoperative patients subsequently received further ipsilateral knee surgeries (P= .08), including 2 total knee arthroplasties. In this PS-matched analysis of patients aged 40 years and older with ACL ruptures, patients who elected nonoperative management had similar subjective outcomes compared with those who elected allograft ACLR. Patients who elected allograft ACLR did not have fewer subsequent operations than those who elected nonoperative treatment. Level III, retrospective cohort study.

Bone-ACL-bone allograft for anterior cruciate ligament reconstruction: Short-term evaluation in a rabbit model with microcomputed tomography.

The standard grafts used for anterior cruciate ligament (ACL) reconstruction are tendon, either patellar tendon, hamstring, or quadriceps. However, the microstructure and composition of tendon differs from ligament. Ideally, the ACL would be replaced with the same tissue. To evaluate the incorporation of a bone-ACL-bone (B-ACL-B) graft for ACL reconstruction, we performed a controlled laboratory study in a rabbit model with microcomputed tomography (μCT). Forty-sixNew Zealand white rabbits were used, with 17 donor rabbits to harvest bilateral B-ACL-Ballografts and 29 rabbits undergoing unilateral ACL reconstruction with B-ACL-Ballograft. Knee specimens were collected for biomechanical testing (n = 14) at 4 and 8 weeks and for μCT analysis (n = 15) at 2, 4, and 8 weeks after surgery. Gross inspection and μCT examination confirmed bone blocks in the appropriate anatomic position. Biomechanical tests revealed no difference in mean load-to-failure force for B-ACL-Ballografts between 4 and 8 weeks. Progressive healing occurred between the bone block and the tunnel as demonstrated by a gradual increase on average bone-volume fraction and total mineral density (TMD) in both femoral and tibial tunnels. Remodeling of the bone block was evidenced by a significant decrease in TMDof both tibial and femoral bone blocks. This is a report of a novel rabbit B-ACL-Ballograft reconstruction model demonstrating early signs of graft remodeling and incorporation. Clinical Relevance: This study demonstrates ACL reconstruction using an anatomically matched ACL allograft, rather than a tendon graft, may be possible based on early findings in this lapine model.

Revision Soft-Tissue Allograft Anterior Cruciate Ligament Reconstruction Is Associated With Lower Patient-Reported Outcomes Compared With Primary Anterior Cruciate Ligament Reconstruction in Patients Aged 40 and Older

To evaluate patient-reported outcomes (PROs) and graft failure rates in revision allograft anterior cruciate ligament reconstruction (ACLR) in patients aged 40 and older and compare them with primary ACLRs. Patients aged 40 and older who underwent arthroscopic soft-tissue allograft ACLR between 2005 and 2016 with a minimum 2-year follow-up were retrospectively reviewed. Patients were grouped based on revision versus primary ACLR. The rate of achieving an International Knee Documentation Committee (IKDC) patient acceptable symptom state (PASS) score was recorded. Patient satisfaction, PROs, and graft failure were compared between groups using the χ2 test, Fisher exact test, and Mann-Whitney U test. We identified 32 patients who underwent revision ACLR and 201 patientswho underwent primary ACLR aged 40 and older who met inclusion criteria with a mean follow-up of 6.2 and 6.9 years, respectively (P= .042). There was a lower rate of concomitant meniscal repair in the primary ACLR group (6%vs 21.9%, P= .007) There were no other differences in chondral injuries, mechanism of injury, or meniscal injuries between groups. The median IKDC score was greater in the primary ACLR group as compared with the revision ACLR group (83.9 vs 70.6, P < .001). Patients who underwent revision ACLR were less likely to achieve the IKDC PASS threshold (82.5% vs 56.3%, P= .001) and were less likely to report satisfaction as compared with patients who underwent primary ACLR (90.5% vs 78.1%, P=.038). No difference in graft failure rates was identified between groups (8% vs 15.6%, P= .180). Revision allograft ACLR in patients aged 40 and older was associated with lower PROs compared with primary ACLR. Patients who underwent revision ACLR failed to meet the IKDC PASS threshold more often and were dissatisfied with procedure results more than twice as often as patients that underwent primary ACLR. III, retrospective cohort study.

Incorporation of Whipstitch Suture in Tibial Interference Fixation Improves Pullout in Anterior Cruciate Ligament Soft Tissue Grafts.

Interference screw fixation of soft tissue grafts is commonly used in anterior cruciate ligament (ACL) reconstruction. The purpose of this study was to determine whether including suture material at the graft-screw interface affects ultimate fixation strength of soft tissue grafts using a tibialis anterior tendon allograft model. Forty fresh-frozen human tibialis anterior tendon allografts were fixed to rigid polyurethane foam simulating the tibial tunnel. Twenty grafts underwent fixation with interference screws and 20 with interference bolts. Within each group, 10 grafts had suture in contact with either the screw or bolt. A load-to-failure test was then performed at a rate of 200 mm/min. The group of allografts with sutures in the tibial tunnel had significantly higher load to failure than the group without sutures. Using interference screw fixation, failure load of the grafts without sutures in the tunnel (535.2 ± 73.40 N) was significantly lower (P = .001) than with sutures in the tunnel (696.3 ± 110.0 N). Using interference bolt fixation, failure load of the grafts without sutures in the tunnel (613.0 ± 83.46 N) was significantly lower (P <.0001) than with sutures in the tunnel (845.8 ± 87.23 N). In a biomechanical model, suture within the tibial tunnel enhances fixation strength with both interference screw and bolt fixation for soft tissue tibialis anterior allografts. Additionally, there was no difference in load to failure when comparing failure of a screw with suture in the tunnel with an interference bolt without suture. Due to improved biomechanical properties, incorporation of suture in the bone-graft interface should be considered when performing soft tissue ACL allograft reconstructions. Failure at the tibial bone-graft interface is a known complication of ACL reconstruction, and incorporation of suture within the interface should be considered for improved biomechanical properties.

Our Preferred Technique for Bone–Patellar Tendon–Bone Allograft Preparation

Anterior cruciate ligament (ACL) reconstruction is an increasingly common procedure as orthopaedic patients seek to remain active longer in life, resulting in more ligamentous knee injuries. Graft selection is at the forefront of decision making in knee reconstruction, with advantages and disadvantages to various grafts, including allograft to autograft. Although the gold standard for the ACL reconstruction of elite athletes and highly active patients has traditionally been bone–patellar tendon–bone autograft (BTB), this graft is not without its disadvantages, such as increased operative time, increased postoperative pain, potential for anterior knee pain, larger incision, violation of the extensor mechanism, and potentially kneeling pain. Soft tissue autografts (hamstring, quadriceps) offer a good alternative; however, they may be associated with higher rerupture rates, as well as associated donor site morbidity. Additionally, soft tissue allografts have a higher graft rupture rate. For this reason, it is the senior author’s preference to perform allograft ACL reconstruction with BTB allograft in appropriately selected patients. We describe our technique for an efficient and reproducible BTB allograft preparation.

The Majority of Patients Aged 40 and Older Having Allograft Anterior Cruciate Ligament Reconstruction Achieve a Patient Acceptable Symptomatic State

To evaluate patient satisfaction, retear rates, and patient-reported outcomes (PROs) in patients aged 40 and older undergoing allograft anterior cruciate ligament reconstruction (ACLR). The secondary goal was to compare these parameters between groups of patients with intact versus failed grafts, and to evaluate these in relation to a historically reported International Knee Documentation Committee (IKDC) patient-acceptable symptoms state (PASS) score. Records of patients aged 40 and older who underwent ACLR between 2005 and 2016 at a single institution with a minimum 2-year follow-up were retrospectively reviewed. Patient-reported satisfaction, outcome scores, and failure rates were analyzed. The rate of achieving a previously defined IKDC PASS score based on younger cohorts was reported, and an updated PASS threshold for older patients was calculated. 201 patients were included with a mean age of 48.6 years (range: 40-68) and mean follow-up of 6.2 years (range: 2.8-11.2). 182 (90.5%) patients reported satisfaction following surgery. 16 (8.0%) patients experienced failure of their ACLR, 10 of which underwent revision ACLR. The median IKDC score in the intact ACLR group was 86.2, compared to 66.7 in the failure group (P < .001). In total, 134 (72.4%) patients in the intact group achieved the historical PASS score of 75.9 on IKDC compared to only 4 (25%) in the failure group (χ2= 15.396, P < .001). An updated IKDC PASS threshold for older cohorts was calculated to be 66.7. Patients aged 40 and older who underwent allograft ACLR had an 8.0% failure rate at a mean follow-up of 6 years. Graft failure in patients aged 40 and older was associated with worse PROs. The majority of patients achieved the historically reported IKDC PASS threshold. Additionally, an updated age-appropriate IKDC PASS score of 66.7 was calculated to aid in future ACLR studies assessing older patients. Level IV.

Effect of Freshly Isolated Bone Marrow Mononuclear Cells and Cultured Bone Marrow Stromal Cells in Graft Cell Repopulation and Tendon-Bone Healing after Allograft Anterior Cruciate Ligament Reconstruction.

Graft cell repopulation and tendon-bone tunnel healing are important after allograft anterior cruciate ligament reconstruction (ACLR). Freshly isolated bone marrow mononuclear cells (BMMNCs) have the advantage of short isolation time during surgery and may enhance tissue regeneration. Thus, we hypothesized that the effect of intra-articular BMMNCs in post-allograft ACLR treatment is comparable to that of cultured bone marrow stromal cells (BMSCs). A rabbit model of hamstring allograft ACLR was used in this study. Animals were randomly assigned to the BMMNC, BMSC, and control groups. Fresh BMMNCs isolated from the iliac crest during surgery and cultured BMSCs at passage four were used in this study. A total of 1 × 107 BMMNCs or BMSCs in 100 µL phosphate-buffered saline were injected into the knee joint immediately after ACLR. The control group was not injected with cells. At two and six weeks post operation, we assessed graft cell repopulation with histological and cell tracking staining (PKH26), and tendon-bone healing with histological micro-computed tomography and immunohistochemical analyses for collagen I and monocyte chemoattractant protein-1 (MCP1). At two weeks post operation, there was no significant difference in the total cell population within the allograft among the three groups. However, the control group showed significantly higher cell population within the allograft than that of BM cell groups at six weeks. Histological examination of proximal tibia revealed that the intra-articular delivered cells infiltrated into the tendon-bone interface. Compared to the control group, the BM cell groups showed broader gaps with interfacial fibrocartilage healing, similar collagen I level, and higher MCP1 expression in the early stage. Micro-CT did not reveal any significant difference among the three groups. BMMNCs and BMSCs had comparable effects on cell repopulation and interfacial allograft-bone healing. Intra-articular BM cells delivery had limited benefits on graft cell repopulation and caused higher inflammation than that in the control group in the early stage, with fibrocartilage formation in the tendon-bone interface after allograft ACLR.

Quantitative assessment of neural elements in a rat model using nerve growth factor after remnant-preserving anterior cruciate ligament reconstruction: a histological and immunofluorescence pilot study

BackgroundImmunofluorescence analyses of anterior cruciate ligament (ACL) allografts following remnant-preserving ACL reconstruction using Achilles tendon allografts have provided evidence for the presence of neural elements. In this study, we aimed to examine the expression of neural elements and quantify the presence of neural cells in ACL remnants and Achilles allografts using nerve growth factor (NGF) therapy after remnant-preserving ACL reconstruction.MethodsExperiments were conducted on 5 pairs of rats (approximately 8 weeks old and weighing 320 g at the time of surgery). Longitudinally, split Achilles tendons from the paired rats were freshly frozen and later defrosted with warm saline and allografted onto the right ACL of the other rat that was partially detached at the femoral attachment site. A sham operation was conducted on the left knee to be used as a control. NGF was injected into both knee joints every week for 6 weeks after surgery. The presence of neural cells in the ACL of the sham-operated knee, allografted Achilles tendon, and ACL remnant was examined 6 weeks post-surgery using H and E and immunofluorescent staining.ResultsH and E staining did not reveal neural cells in any of the three groups. However, immunofluorescence analysis showed the presence of nestin-positive neural elements in the normal ACL tissues as well as ACL remnants. Additionally, neural elements were examined in 7 of the 8 (87.5%) allograft tissues. Quantitative analysis showed no difference in the number or area of nuclei among the three groups. However, the number and area of neural cells in the Achilles allografts were significantly lower than those in the other two groups (p = 0.000 and p = 0.001, respectively).ConclusionOur observations indicate that ACL remnants promote the new ingrowth and persistence of neural cells. We suggest that the ingrowth of neural elements can support the persistence and new ingrowth of mechanoreceptors, thereby enhancing the functional stability of knee joints. Moreover, the expression of neural cells in the Achilles allografts was lower than that in normal ACL tissues and ACL remnants in the quantitative evaluation, thereby confirming the essential role of ACL remnants in knee joint functionalization.