Allograft Anterior Cruciate Ligament Reconstruction Research Articles

Current status of graft choice in adults for anterior cruciate ligament reconstruction: a systematic review and meta-analysis

The anterior cruciate ligament (ACL) is a frequently performed surgical procedure in the field of sports medicine, and graft selection is an essential aspect of ACL reconstruction (ACLR) that has been shown to optimize post-operative rehabilitation, facilitate return to full sporting function and reduce the risk of complications. However, there needs to be more agreement regarding optimal graft choice. The present study aims to identify the optimal graft choice in the adult population undergoing ACLR. The current systematic review explores the electronic database of online libraries of academic institutions from 2011 to 30 September 2022 and compared the clinical outcomes of autograft and allograft for ACLR, which provides an evidence-based approach for graft selection. The findings of our present study delineate that ACLR in adult populations with autograft is the most promising choice for ligament tear over allograft based on lower failure rate, reduced complications, and high cost-effectiveness. However, there was no significant difference in overall IKDC, pivot shift, Lachman test, and Tegner activity. This critical analysis recommends that for an adult population, ACLR with autograft can provide better clinical results than an allograft, but further studies carried out about other parameters affecting the long-term stability, quick return, and physical therapy adopted outside the supervision of the respective surgeon would be required.

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.

Autograft patellar bone-tendon-bone use does not increase operative time in anterior cruciate ligament reconstruction

BackgroundAnterior cruciate ligament reconstruction (ACLR) is a common procedure that has been shown to have relatively good outcomes amongst various graft types. Operative time in ACLR has been found to influence outcomes and cost. The purpose of this study was to evaluate the association of operative time in primary arthroscopically performed anterior cruciate ligament reconstruction (ACLR) and graft type while controlling for confounders that influence time. MethodsAll patients who received ACLR between 2018 and 2022 were included in this retrospective cohort study. Exclusion criteria consisted of age (≤16 years), revisions, concomitant ligament reconstruction or tendon repairs, or other simultaneously performed procedures that could potentially add substantial variation in operative time. The primary outcome was operative time. Graft types included allograft, bone-tendon-bone (BTB) autograft, hamstring tendon (HS) autograft and quadriceps tendon (QT) autograft. ResultsA total of 1813 primary ACLRs were included. The average operative time was 98.9 ± 33.0 min. Graft utilization varies considerably among surgeons. The most used graft type was BTB autograft (42.6%) followed by HS autograft (32.3%) and allograft (21.4%). Only 68 cases (3.8%) used a QT autograft. Seven of the 15 included surgeons primarily used BTB autograft. One surgeon predominately used QT autograft. No difference in operative time was observed among the autograft types (p = 0.342). Allograft ACLR was significantly faster by 27–33 min compared to using BTB autograft, HS autograft, or QT autograft (p < 0.001). ConclusionOperative time did not vary by type of autograft selected. Allograft ACLR was performed approximately 30 min faster than autograft ACLR. Further studies examining the effect on patient outcomes of reduced operative time and minimizing graft harvest morbidity in ACLR is important to more accurately determine the cost-effectiveness of allograft ACLR.

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.

Poster 317: Preoperative and Operative Characteristics in the Context of Patient-Reported Outcomes for ACLR in Patients Aged 40 or Older: Allograft versus Autograft

Objectives: Anterior cruciate ligament reconstruction (ACLR) has traditionally been reserved for younger, more active patients that sustain ACL injuries. Since life expectancy and healthcare delivery have been improving, more patients have been wanting to maintain active lifestyles and continue participating in sports at older age. There has thus been an interest in studying ACLR outcomes for this older patient cohort, particularly patients aged 40 and older. Although these patients may receive nonoperative treatment more frequently, prior literature has studied ACLR outcomes in this population, yet these studies are limited in size and granularity. Despite the fact that patient-reported outcome measures (PROMs) are being increasingly used in orthopaedics to define successful treatment and even influence prior authorization and reimbursement policies, PROM data is scarce for this population. Conventional thought states that surgical technique varies for this patient population compared to younger patients particularly regarding graft type, with surgeons opting for allograft use more often in older patients. Few studies have assessed the use of allograft versus autograft in these patients, with almost no studies reporting on PROMs. To the knowledge of the authors, no study has evaluated ACLR outcomes using the Knee Injury &amp; Osteoarthritis Outcome Score (KOOS), a validated PROM commonly used for ACLR. The purpose of this study was to compare baseline factors, surgical characteristics, and outcomes between patients aged 40 and over that received allograft and those that received autograft for primary ACLR. The secondary aim was to report on available KOOS data for these patients. The hypothesis was that patients receiving allograft and autograft would demonstrate similar outcomes. Methods: This was a retrospective cohort study conducted at a single ambulatory surgical center in a metropolitan area. The institutional electronic medical record (EMR) was queried for ACLRs from 2009 and 2016 using CPT code terminology for ACLR and related procedures. Patients aged younger than 40, revision procedures, and concomitant ligaments reconstructions/repairs were excluded. Demographic, injury, and surgical characteristics were extracted via EMR chart review. Costs regarding implants, day of surgery, and the two-year episode of care were determined using time-driven activity-based costing. Clinical outcomes included graft failure/re-rupture and re-operations within two years after index ACLR. The institutional PROM database was queried for available KOOS data at minimum two-year follow-up and cross-referenced with the initial patient list. Single Assessment Numeric Evaluation (SANE) was also included. Chi-square, Fisher exact, and student t-tests were conducted to identify group differences. Results: A total of 141 patients were included. The cohort was mostly female (57.4%) with an average age of 47 (range: 40 to 66). Average BMI was 26.5, and most patients (72.6%) were ASA score 1. Most patients had acute injuries under six months (90.1%) and had some degree of pre-existing osteoarthritis (61.0%), although this was mostly mild and almost exclusively patellofemoral. Most patients were treated with allograft (67.4%), followed by hamstring autograft (17.7%) and bone-tendon-bone autograft (14.9%). Approximately 58.2% injured at least one meniscus, with 89.0% of these receiving operations consisting of almost exclusively meniscectomies (89.0% of operations). ACLR failure and re- operation rates at two years were relatively low at 4.3% and 7.8%, respectively. Only 123 patients (87.2%) and 77 patients (54.6%) reported SANE and KOOS data at two-year follow-up, respectively. Average baseline and two-year KOOS were 59.2 and 80.0, respectively, corresponding to an average two-year improvement of +20.8. Baseline and two-year SANE were 61.2 and 85.3, respectively, corresponding to an average improvement of +23.3. Between patients receiving allograft and patients receiving autograft, there were no differences in re-rupture or re-operation rates, two-year KOOS, or two-year SANE. Statistically significant differences (allograft vs autograft) were identified for age (48 vs 45 years old, p=0.0037), operative time (91 vs 105 minutes, p=0.0053), selection of screw vs suspensory fixation in the femur (86.3% vs 47.8%, p&lt;0.0001), femoral and tibial implant costs ($158.55 vs $247.12, p&lt;0.0001), and overall surgical and two-year costs ($5715.90 vs $3235.42 and $6480.63 vs $4017.61, respectively, p&lt;0.0001). More patients in the allograft group had pre-existing arthritis, but this did not reach significance (66.3% vs 50.0%, p=0.0626). Conclusions: Primary ACLR for patients aged 40 and older was shown to provide favorable clinical outcomes and PROs. This is one of the largest existing samples for this patient cohort and is the first study to the knowledge of the authors to provide KOOS data for this older patient population receiving ACLR, which demonstrated on average notable improvements at two years. Although most patients received allograft, outcomes did not differ between these patients and those receiving autografts. Although allograft ACLRs exhibited lower operative time and choice of less costly implants, these did not outweigh the surgical and two-year costs associated with allograft use versus native tissue harvest and did not lead to improved PROs. The interplay of these variables, in addition to presence and degree of pre-existing arthritis, on graft choice and outcomes may need to be further elucidated with studies of higher sample size and PROM response rate. Nonetheless, these results agree with prior literature and suggest that primary ACLR in the context of patients aged 40 and older provides good outcomes regardless of graft type used. [Table: see text][Table: see text]

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.

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.

Optimal Surgical Treatment Method for Anterior Cruciate Ligament Rupture: Results from a Network Meta-Analysis.

BackgroundPrevious studies have shown that primary repair (PR) and anterior cruciate ligament reconstruction (ACLR) can effectively treat ACL injuries. Our study aimed to compare different treatments of ACL tears, including autograft, allograft, hybrid graft ACLR, and PR, by assessing clinical outcomes and adverse events.Material/MethodsPubMed, Cochrane Library, Embase, and CNKI databases were searched and a frequentist-framework network meta-analysis was used.ResultsOverall, PR with augmentation was superior to ACLR only for activity recovery (WMD 0.28 95%CI [0.07 to 0.49]), and there was no significant difference shown between PR without augmentation and ACLR. ACLR with irradiated allograft was a poor option for the treatment of ACL rupture, showing the weakest subjective evaluations and functional outcomes and worst safety profile. PR with or without augmentation provided fairly good postoperative efficacy results and produced less postoperative knee laxity than irradiated allograft ACLR (PR: standardized mean difference [SMD] −1.27 [−1.80 to −0.74]; ACLR: SMD −1.36 [−1.88 to −0.83]). However, PR without augmentation showed a high failure rate compared with autograft ACLR (autograft vs PR without augmentation: risk ratio 0.29 [0.10 to 0.85]).ConclusionsFor surgical treatment of ACL rupture, irradiated allograft ACLR had the worst efficacy and safety and is not recommended. PR may be an ideal treatment method in terms of efficacy but it is related to a significantly higher revision risk if without augmentation. Autograft ACLR may be the preferred method currently available for most patients requiring surgical treatment of ACL rupture.

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.

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.

Revision Risk of Soft Tissue Allograft Versus Hybrid Graft After Anterior Cruciate Ligament Reconstruction

Background: When a harvested hamstring autograft is deemed by the surgeon to be of inadequate diameter, the options include using the small graft, using another autograft from a different site, augmenting with an allograft (hybrid graft), using a different configuration of the graft (eg, 5- or 6-stranded), or abandoning the autograft and using allograft alone. A small graft diameter is associated with a higher revision risk, and using another autograft site includes added harvest-site morbidity; therefore, use of a hybrid graft or an allograft alone may be appealing alternative options. Revision risk for hybrid graft compared with soft tissue allograft is not known. Purpose: To evaluate the risk for aseptic revision surgery after primary anterior cruciate ligament reconstruction (ACLR) using a soft tissue allograft compared with ACLR using a hybrid graft in patients 25 years and younger. Study Design: Cohort study; Level of evidence, 3. Methods: Data from a health care system’s ACLR registry were used to identify primary isolated unilateral ACLRs between 2009 and 2016 using either a hybrid graft (hamstring autograft with soft tissue allograft) or a soft tissue allograft alone. Multivariable Cox proportional hazards regression was used to evaluate risk for aseptic revision after ACLR according to graft used after adjustment for age, allograft processing, tunnel drilling technique, and region where the primary ACLR was performed. Results: The cohort included 2080 ACLR procedures; a hybrid graft was used for 479 (23.0%) ACLRs. Median follow-up time was 3.4 years (interquartile range, 1.8-5.1 years). The crude 2-year aseptic revision probability was 5.4% (95% CI, 4.3%-6.7%) for soft tissue allograft ACLR and 3.8% (95% CI, 2.3%-6.4%) for hybrid graft ACLR. After adjustment for covariates, soft tissue allograft ACLR had a higher risk of aseptic revision during follow-up compared with hybrid graft ACLR (hazard ratio, 2.00; 95% CI, 1.21-3.31; P = .007). Conclusion: Soft tissue allografts had a 2-fold higher risk of aseptic revision compared with hybrid graft after ACLR. Future studies evaluating the indications for using hybrid grafts and the optimal hybrid graft diameter is needed.

Revision Risk Of Soft Tissue Allograft Versus Hybrid Graft Following Anterior Cruciate Ligament Reconstruction

Objectives: Prior studies have found smaller hamstring autograft diameter to be associated with a higher revision risk following anterior cruciate ligament reconstruction (ACLR). Therefore, when a harvested hamstring autograft is deemed by the surgeon to be of inadequate diameter, the options include: using the small graft, using another autograft from a different site, augmenting with an allograft (hybrid graft), or abandoning the autograft and using allograft alone. Using another autograft site includes added harvest-site morbidity, therefore utilization of an allograft to augment the autograft (hybrid) or allograft alone may be an appealing alternative option. Revision risk for hybrid graft compared to soft tissue allograft in is not known. The purpose of our study was to determine the risk for aseptic revision following soft tissue allograft ACLR compared to hybrid graft ACLR in patients 25 years and younger. Methods: Data from a healthcare system’s ACLR registry was used to conduct a cohort study. Primary isolated unilateral ACLR from 2009-2016 using either a hybrid graft (hamstring autograft + soft tissue allograft) or soft tissue allograft alone were identified. Time-to-aseptic revision surgery following primary ACLR was the primary endpoint. Multivariable Cox proportional hazard regression was used to evaluate risk for aseptic revision according to graft utilization after adjustment for age, allograft processing, tunnel drilling technique, and region where the primary ACLR was performed. Analysis censored patients at the time lost to follow-up (healthcare plan termination or death) or the end of study follow-up. A sandwich covariance matrix estimator was used to account for clustering of ACLR at the surgeon level. Results: The cohort included 2080 ACLR performed by 161 surgeons at 42 healthcare centers. Soft tissue allograft was used for 1601 (77.0%) ACLR and hybrid graft for 478 (23.0%). For the soft tissue allograft ACLR group, mean age was 19.2 (standard deviation [SD]=3.5) years, 79.1% of allografts were irradiated or chemically processed, and 50.4% of femoral tunnels were through the trans-tibial technique. For the hybrid graft ACLR group, mean age was 18.4 (SD=3.3) years, 81.5% were irradiated or chemically processed, and 72.3% of femoral tunnels were through the trans-tibial technique. Median follow-up time was 3.4 years (interquartile range=1.8-5.1 years). The crude 2-year aseptic revision probability was 5.4% (95% confidence interval [CI]=4.3-6.7) for soft tissue allograft ACLR and 3.8% (95% CI=2.3-6.4) for hybrid ACLR. After adjustment for covariates, soft tissue allograft ACLR had a higher risk of aseptic revision during follow-up compared to hybrid graft ACLR (hazard ratio=2.00, 95% CI=1.21-3.31, p=0.007). Conclusion: Soft tissue allograft had twice the risk of aseptic revision compared to hybrid graft following ACLR. Based on our findings, when faced with a hamstring autograft that is deemed to have an inadequate diameter, augmenting it with allograft tendon may be preferred over abandoning it for an allograft alone. Future study evaluating the indications and the optimal hybrid graft diameter is needed.

Terminal Sterilization of Anterior Cruciate Ligament (ACL) Allografts: A Systematic Review of Outcomes

Anterior cruciate ligament (ACL) injuries are common and reconstruction can be completed with either autograft or allograft tissue. However, there is concern about an increased failure rate with allograft tissue. The purpose of this study was to systematically review the available evidence to determine the effect of irradiation and level of dose on the failure rates of allograft in ACL reconstruction. A literature search was performed using PubMed, Scopus, and Web of Science from January 2000 to September 2013. Inclusion criteria consisted of the following: (1) primary, unilateral, single-bundle allograft ACL procedure, (2) studies with data documenting graft type and terminal sterilization technique, (3) subjective assessments of outcome, and (4) objective assessments of outcome. Studies without reported subjective and objective outcomes and those pertaining to revision ACL reconstruction were excluded. Failures were defined and compared between irradiated and non-irradiated grafts, as well as between grafts irradiated with 1.2 - 1.8 Mrad and those with 2.0 - 2.5 Mrad. Of the 242 articles identified via initial search, 17 studies met the final inclusion criteria. A total of 1,090 patients were evaluated in this study, all having undergone unilateral primary ACL reconstruction with allograft tissue with 155 failures. The failure rate between non-irradiated (98/687, 14.7%) and irradiated (57/408, 14.0%) was not statistically significant (p = 0.86). Grafts in the high-dose irradiation group (27/135, 20.0%) had a statistically significant higher (p < 0.001) rate of failure than those in the low-dose irradiation group (30/273, 10.6%). The irradiation of an allograft increases the risk of failure after an ACL reconstruction but the use of lower doses of radiation decreases that risk.