Allograft for knee ligament surgery: an American perspective

Graft Options for the Reconstruction of Multi-ligament Knee Injury: A Systematic Review

Introduction

The literature lacks enough synthesis on which autograft option is suitable for a particular ligament reconstruction during multi-ligament reconstruction. This study aims to conduct a systematic review of existing literature to determine graft options available for the reconstruction of various ligaments in the context of multi-ligament knee injury.

Methods

A systematic review was conducted following the preferred research items for systematic reviews and meta-analyses (PRISMA) guidelines. It was registered in PROSPERO (CRD42024498917). Studies that met the predefined inclusion and exclusion criteria were included in this systematic review.

Results

Out of 8070 identified citations, 16 studies with a total of 640 patients(645 knees), including 420(65.6%) males and 220(34.4%) females, with a mean age of 35.1 years were included. Among 16 papers included in this review, combining autografts, allografts, or synthetic grafts was the preferred choice in seven studies. Autografts were chosen in five research studies, while allografts were preferred in four. For Anterior Cruciate Ligament (ACL) reconstruction: Eleven studies used only autografts, two used only allografts, and 1 study used both autografts and allografts. For Posterior Cruciate Ligament (PCL) reconstruction, nine studies used allografts, six used autografts, and 1 study used synthetic graft. For Posterior Lateral Corner (PLC) reconstruction, six studies used allografts, five used autografts, and 1 study used synthetic graft. For posterior medial corner (PMC) reconstruction, eight studies used autografts, five used allografts, and only one used synthetic grafts.

Conclusion

A combination of autografts, allografts, or synthetic grafts was the preferred graft option for multi-ligament knee reconstruction. Autografts are the most preferred option for ACL and PMC reconstruction, whereas allografts are the most preferred option for PCL and PLC reconstruction. The most preferred autograft was the Hamstring Tendon (HT) autograft. Similarly, the tendoachillies (TA) was the most used allograft. However, the strength of the evidence in this review is moderate to low.

Changes in the mechanical properties of tibialis anterior and peroneus longus allograft depending on sterilization method and storage time

Aims

The aim of the present research was to analyze the effects of different sterilization methods and storage times on the mechanical properties (load at first break, strain at first break, maximum load, strain at maximum load, and Young's modulus of elasticity) of different allografts compared to native groups.

Methods

Two types of grafts were harvested from human cadavers: 165 tibialis anterior (TA) and 166 peroneus longus (PL) tendons. According to the two types of sterilization methods (γ and electron beam irradiation) or the lack of one, and the six types of storage time (one to six months), 36 groups were created. In addition, we created a 1 to 1 native group, which was not sterilized and stored, tested within four hours of collection.

Results

In the results of tendon type TA compared to TA native group, we observed significant differences at the fifth month of storage for all measured parameters. Load at first break of the frozen values at the fifth month was significantly inferior to the native group (p = 0.034). For strain at first break and strain at maximum load, all sterilization methods were significantly inferior at the fifth month (p = 0.003 to p = 0.009). Maximum load values were significantly superior with E-beam irradiation at the fifth month (p = 0.003), and also significantly higher with γ irradiation at the fifth month (p = 0.009). Young's modulus showed significantly inferior values in the frozen tendons at the fifth month (p = 0.001 to p = 0.003). In tendon type PL, no significant differences were found for any of the tested parameters compared to the native group.

Conclusion

Our results indicate that freezing alters mechanical properties via the decrease seen in the ultimate tensile strength. In addition, at the fifth and sixth months of storage, time could notably affect allografts rather than the sterilization procedures.

Lower ACLR Failure Rates in Bone-Soft Tissue Versus Soft Tissue-Only Allografts in Adults: A Systematic Review and Meta-analysis

BACKGROUND

While allografts are commonly used for anterior cruciate ligament reconstruction (ACLR), evidence to guide specific allograft selection is lacking.

PURPOSE

To compare clinical and graft failure rates after ACLR using soft tissue-only allografts and bone-soft tissue allografts in adults.

STUDY DESIGN

Systematic review and meta-analysis; Level of evidence, 4.

METHODS

English-language studies with clinical outcome data on primary and revision ACLR in adults with nonirradiated soft tissue-only and bone-soft tissue grafts were identified in the search. Data extracted included allograft type, patient characteristics, follow-up time, and failure rates. The cumulative failure rate was defined as International Knee Documentation Committee grade C/D, graft retear, grade ≥2+ Lachman, grade ≥2+ pivot shift, and/or side-to-side KT-1000 laxity of >5 mm. The graft rupture rate was defined solely by the proportion of patients who had a graft rupture. Meta-analyses using the inverse variance method were used to estimate the pooled rates with 95% CIs. Subgroup analysis was conducted to compare allograft types and determine whether age, sex, and follow-up time influenced the estimates.

RESULTS

A total of 14 studies met the inclusion criteria: 7 investigated bone-soft tissue allografts, 6 investigated soft tissue-only allografts, and 1 investigated both. The comparative study showed a difference in the cumulative failure rate between bone-patellar tendon-bone and soft tissue-only allografts. The pooled cumulative failure rates for bone-soft tissue and soft tissue-only allografts were 11% (95% CI, 7-17) and 20% (95% CI, 14-29), respectively (P = .05). The pooled graft rupture rates for bone-soft tissue and soft tissue-only allografts were 6% (95% CI, 4-9) and 13% (95% CI, 7-23), respectively (P = .07).

CONCLUSION

The meta-analysis results showed that bone-soft tissue allografts have lower cumulative failure rates than soft tissue-only allografts. Bone-soft tissue allografts may be the preferred allograft choices for ACLR.

Anterior Cruciate Ligament Allograft Reconstruction in Females Can Produce Outcomes Comparable to Those of Autografts in Male Counterparts

There are unique anatomical and geometric risk factors that contribute to higher injury rates of the anterior cruciate ligament (ACL) in women. Allografts are an important alternative option for female patients.Patients who underwent primary ACL reconstruction were retrospectively evaluated. The case group comprised female patients with ACL allograft reconstruction, and the control group comprised male patients with ACL reconstruction. Functional and clinical evaluations were based on the pre- and postoperative Cybex test, Lysholm score, International Knee Documentation Committee subjective and objective measurement criteria, and Tegner Activity Scale questionnaires. Radiological comparisons were performed using the femorotibial angle (FTA), posterior tibial slope (PTS), and intercondylar notch width (INW). The roof inclination angle (RIA) was assessed using magnetic resonance imaging.The two groups (female [44] and male [88]) had an average follow-up period of 57.9 ± 19.3 months and average ages of 36.5 ± 10.9 and 35.2 ± 11.7 years, respectively. Functional and clinical outcomes showed no differences between the groups, except that the return to the preinjury activity level was higher in the female group (95% vs. 77%, p < 0.001). The female group showed larger FTA and PTS and smaller INW and RIA than those of the male group (p < 0.001, 0.008, <0.001, and 0.035, respectively).Female ACL allograft reconstruction showed comparable outcomes to those of their male counterparts, and the return to preinjury activity levels was significantly higher in women. However, women showed lower activity levels and were more vulnerable to geometric risk factors than their male counterparts.

Evaluating Donor-Recipient Sex Mismatch in Anterior Cruciate Ligament Reconstruction With Allograft: Outcomes at 2 Years Postoperatively

Background

Female patients tend to suffer a greater risk of reinjury and worse patient-reported outcome measures (PROMs) after anterior cruciate ligament reconstruction (ACLR) than male patients, regardless of the graft type used.

Purpose/Hypothesis

This study explored the role of donor-recipient sex mismatching to help explain these sex-based disparities in outcomes after ACLR with an allograft. The hypothesis was that allograft donor-recipient sex mismatch would adversely affect surgical outcomes at a 2-year follow-up, with male-to-female graft donations yielding the lowest rates of success.

Study Design

Cohort study; Level of evidence, 3.

Methods

Patients who underwent primary ACLR with an allograft between 2012 and 2022 were eligible for recruitment. The following PROMs were collected from baseline through a 2-year follow-up: Knee injury and Osteoarthritis Outcome Score subscales, Marx activity rating scale, visual analog scale for pain, and Veterans RAND 12-Item Health Survey. Demographic and graft-specific variables were also collected. Sex-matched cases were compared with sex-mismatched cases and an identical subgroup analysis was performed for female patients only.

Results

Of the 112 included patients (N = 70 women), 59 (52.7%) were sex mismatched. The mean patient age was 40.7 ± 10.9 years, and the mean body mass index was 26.8 ± 4.7 kg/m2. Most reconstructions (89.3%) used a semitendinosus tendon graft, with a mean implanted graft diameter of 9.7 ± 0.5 mm (quadrupled). Of the mismatched cases, 96.6% involved a male allograft donated to female recipients. Overall, the matched group demonstrated higher PROM scores across all time points compared with the mismatched group, although statistical significance was only reached for the Marx score at baseline (P = .012) and 1 year postoperatively (P = .022). In the female-only subgroup analysis, a larger graft diameter was measured in the mismatched cases (receiving male allografts) compared with the matched female cases (9.7 ± 0.6 vs 9.2 ± 0.4 mm, respectively; P = .002). Moreover, the mismatched cases tended to report better postoperative PROM scores, although this trend was not statistically significant.

Conclusion

The study findings indicated that male donors provided larger allografts than female donors, and that donor-recipient allograft sex matching did not contribute significantly to ACLR outcomes. Other factors may be more important to outcomes in female patients.

Management of Multiligament Knee Injuries Using Anatomic Autograft Reconstructions: A Case Series

While proven effective management of multiligament knee injury (MLKI) using allograft is often reported, it has shown an increased risk for graft failure compared with autograft and raises availability and cost issues. Osseous stock preservation and tunnel convergence avoidance led us to develop a compromise innovative surgical procedure using only ipsilateral autograft for anatomic reconstruction of Schenck III-L or higher MLKI. We report the description and early outcomes of our initial experience. Our strategy consisted of an anatomic single-bundle posterior cruciate ligament reconstruction with quadriceps tendon autograft and a "Versailles" reconstruction for the posterolateral corner, which we modified to reconstruct the anterolateral ligament in case of anteromedial rotatory instability, called "full lateral." A second-stage surgery was planned for anterior cruciate ligament reconstruction using a bone-patellar tendon-bone autograft. Outcomes were Lysholm, Tegner, and International Knee Documentation Committee (IKDC) scores for functional status, Short Form 12 (SF-12) for quality of life, and visual analog scale (VAS) for pain. Complications, full weight-bearing, return to work, and sport were also computed. Between March 2019 and August 2020, 10 patients were included. At follow-up, light pain was found in nine patients with a mean VAS of 1.2 ± 2.16 during the day. The mean Lysholm, Tegner, and subjective IKDC scores were good, with 61.2 ± 20.6, 2.8 ± 2.1, and 52.6 ± 20.4, respectively. However, quality of life was altered with poor SF-12 scores. In our first 10 patients with Schenck III-L or higher MLKI, our procedure using only ipsilateral autograft enabled correct daily knee functional activities while preserving osseous stock.

Establishing a bone bank within a hospital setting in India: early insights from a tertiary care center in Northern India-a review article

When addressing bone defects resulting from trauma, infection, or tumors, the use of allogenic bone is often necessary. While autografts are considered the standard, they have limitations and can lead to donor site morbidity. Consequently, there has been exploration into the feasibility of utilizing allogenic bone and bone graft replacements. Allogenic bone transplants are acquired from donors following rigorous procurement, sterile processing, and donor screening procedures. To ensure the safe storage and effective utilization of allograft material, a bone banking system is employed. Establishing and managing an orthopedic bone bank, entails navigating complex legal and medical organizational aspects. This paper examines the establishment and operation of bone banks in India, drawing upon our first-hand experience in managing one at a tertiary care center in Northern India.Level of evidence: Level IV.

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

Background

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.

Purpose

To assess the revision rate after primary ACL reconstruction with allograft and to compare revision rates based on allograft tissue type and characteristics.

Study Design

Cohort study; Level of evidence, 3.

Methods

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.

Results

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).

Conclusion

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.

Combined reconstruction of medial collateral ligament and posterior cruciate ligament using one femoral tunnel: a technical note and case report applicable to limited-resource settings

Knee dislocations are severe injuries difficult to treat. Specially in low-resources scenarios, reconstruction of multiple ligaments can be challenging. We describe a technical note that can be reconstruct multi ligaments using ipsilateral hamstrings autograft. A posteromedial knee incision is made to visualise the medial corner of the knee and to reconstruct medial collateral ligament (MCL) and posterior cruciate ligament (PCL) with semitendinosus and gracilis tendon graft, using one femoral tunnel from the anatomic femoral insertion of the MCL to the anatomic femoral insertion of the PCL. After 1-year follow-up, the patient returned to his previous function with a Lysholm score of 86. This technique can reconstruct more than one ligament anatomically with limited graft resource.

Anterior Cruciate Ligament Revision Surgery Associated to Lateral Collateral and Anterolateral Ligaments Reconstruction With Single Achilles Tendon Allograft and Single Femoral Tunnel

Lateral collateral ligament (LC) injuries that go unnoticed when associated with an anterior cruciate ligament (ACL) tear can increase stress forces on the ACL graft causing its failure. Furthermore, it is a main stabilizer to varus stress and external rotation. On the other hand, the reinforcement of anterolateral structures during ACL reconstruction has regained popularity in recent years, because evidence has shown that it increases the control of rotational laxity and decreases ACL graft failures, especially in revision surgery. The present article shows a technique to perform an ACL reconstruction, associated with the reconstruction of the LCL and of the anterolateral ligament using a single Achilles tendon allograft, which is split after the fixation of the ACL graft into two fascicles.

No Difference in Knee Kinematics Between Anterior Cruciate Ligament-First and Posterior Cruciate Ligament-First Fixation During Single-Stage Multiligament Knee Reconstruction: A Biomechanical Study

Background:

For combined reconstruction of both the anterior cruciate ligament (ACL) and the posterior cruciate ligament (PCL), there is no consensus regarding which graft should be tensioned and fixed first.

Purpose:

The purpose of this study was to determine which sequence of graft tensioning and fixation better restores normal knee kinematics. The hypothesis was that ACL-first fixation would more closely restore normal knee kinematics, graft force, and the tibiofemoral orientation in the neutral (resting) position compared with PCL-first fixation.

Study Design:

Controlled laboratory study.

Methods:

A total of 15 unpaired human cadaveric knees were examined using a robotic testing system under the following 4 conditions: (1) 89.0-N anterior tibial load at different knee angles; (2) 89.0-N posterior tibial load at different knee angles; (3) combined rotational 7.0-N·m valgus and 5.0-N·m internal rotation load (simulated pivot shift) at 0°, 15°, and 30° of flexion; and (4) 5.0-N·m external rotation load at 0°, 15°, and 30° of flexion. The 4 evaluated knee states were (1) intact ACL and PCL (intact), (2) ACL and PCL deficient (deficient), (3) combined anatomic ACL-PCL reconstruction fixing the ACL first (ACL-first), and (4) combined anatomic ACL-PCL reconstruction fixing the PCL first (PCL-first). A 9.0 mm–diameter quadriceps tendon autograft was used for the ACL graft, tensioned with 40.0 N at 30° of flexion. A 9.5 mm–diameter hamstring tendon autograft (gracilis and semitendinosus, quadrupled loop, and augmented with an additional allograft strand if needed), tensioned with 40.0 N at 90° of flexion, was used for the PCL graft.

Results:

There were no statistically significant differences between ACL-first and PCL-first fixation regarding knee kinematics. ACL-first fixation restored anterior tibial translation to the intact state at all tested knee angles, while PCL-first fixation showed higher anterior tibial translation than the intact state at 90° of flexion (9.05 ± 3.05 and 5.87 ± 2.40 mm, respectively; P = .018). Neither sequence restored posterior tibial translation to the intact state at 30°, 60°, and 90° of flexion. At 15° of flexion, PCL-first fixation restored posterior tibial translation to the intact state, whereas ACL-first fixation did not.

Conclusion:

There were no differences in knee laxity between ACL-first and PCL-first fixation with the ACL graft fixed at 30° and the PCL graft fixed at 90°.

Clinical Relevance:

This study showed that there was no evidence to support the use of one tensioning sequence over the other in single-stage multiligament knee reconstruction.

Similar biomechanical properties of four tripled tendon graft models for ACL reconstruction

PURPOSE

The present study tested and compared the biomechanical properties of four different triplicate graft tendon techniques.

METHODS

32 tripled tendons from the common extensor muscle of bovine fingers were tested on a material testing machine, passing the end loop over a metal rod of a clevis connected to the load cell on the upper side, and fixing the lower end to a clamp. The samples were divided into four groups: (A) tripled with a free end sutured only to one of the two fixed bundles (B) tripled with a free end positioned between the two fixed strands and sutured to both (C) tripled with an S-shape and all the three strands sutured together at the upper and lower extremities of the graft (D) partially quadrupled with the free end sutured together with the other three bundles at the upper extremity. Each sample was pretensioned at 50 N for 10 min and then subjected to 1000 load control cycles between 50 and 250 N. Finally, each sample was subjected to a load to failure test. Authors also present some preliminary results on the feasibility of a non-contact and full-field Thermoelastic Stress Analysis technique, based on Infrared Thermography, to evaluate the level of stress on the whole graft, and hence on each strand, during fatigue loading.

RESULTS

Eighty five percent of the samples failed at the level of the clamp. The cyclical elongation progressively decreased in all the samples and there was a simultaneous increase in stiffness. An increased stiffness was noted between Group 2 vs Group 3 and Group 2 vs Group 4 at the 500th and 1000th cycle. The failure loads were as follows: (a) 569.10 N, (b) 632.28 N, (c) 571.68 N, (d) 616.95 N. None of the parameters showed a statistically significant difference between the four groups.

CONCLUSION

This study reported similar biomechanical behavior of four different models of tripled grafts suitable for ACL reconstruction. In addition, the biomechanics of overall tripled tendon grafts seems more affected by the viscoelastic property of the tendon itself rather than the preparation method.

The treatment of posterolateral knee instability with combined arthroscopic popliteus bypass and PCL reconstruction provides good-to-excellent clinical results in the mid-term follow-up

PURPOSE

The purpose of this study was to evaluate the clinical outcomes of patients who were treated with an arthroscopic popliteus bypass (PB) technique, in cases of a posterolateral rotational instability (PLRI) and a concomitant posterior cruciate ligament (PCL) injury of the knee.

METHODS

This was a retrospective case series in which 23 patients were clinically evaluated after a minimum of 2 years following arthroscopic PB and combined PCL reconstruction. Lysholm, Tegner and Knee Injury and Osteoarthritis Outcome scores as well as visual analog scales (VAS) for joint function and pain were evaluated. Posterior laxity was objectified with stress radiography and a Rolimeter examination. Rotational instability was graded with the dial test.

RESULTS

23 patients were available for follow-up, 46.0 ± 13.6 months after surgery. The median time interval from the initial injury to the surgery was 6.0 (3.5;10.5) months. The postoperative Lysholm Score was 95.0 (49-100); the Tegner Score changed from 6.0 (3-10) before the injury to 5.0 (0-10) at the follow-up examination (p = 0.013). The side-to-side difference on stress radiography (SSD) of posterior translation changed from 10.4 (6.6-14.8) mm before the injury to 4.0 (0.2-5.7) mm postoperatively (p < 0.01). Rotational instability was reduced to grade A (82.6%) or B (17.4%) (IKDC). The Rolimeter SSD was 2.0 (0-3) mm at the follow-up examination. VAS Function 0 (0-5), VAS pain 0 (0-6).

CONCLUSIONS

The arthroscopic PB graft technique provided good-to-excellent clinical results in the mid-term follow-up in patients with type A PLRI and concomitant PCL injury. However, an exact differentiation of lateral, rotational and dorsal instabilities of posterolateral corner (PLC) injuries is crucial, for the correct choice of therapy, as cases with lateral instabilities require more complex reconstruction techniques. Arthroscopic posterolateral corner reconstruction is a safe procedure with a high success rate in the mid-term follow-up.

LEVEL OF EVIDENCE

IV.

Different timing in allograft and autograft maturation after primary anterior cruciate ligament reconstruction does not influence the clinical outcome at mid-long-term follow-up

PURPOSE

The use of allografts in primary anterior cruciate ligament reconstruction (ACLR) is increasing although they are still supposed to be associated to greater risk of re-rupture due to a slower and less efficient graft maturation. The aim of this prospective randomized controlled study was to compare the graft maturation after ACLR with allograft and autograft by MRI at 6- and 12-month follow-up and integrate these data with the functional and clinical results observed at 6-, 12- and 60-month follow-up.

METHODS

Fifty patients with indication to primary ACLR were randomly and equally divided into hamstring autograft or allograft tendon groups. The graft maturation was measured at 6- and 12-month follow-up by the SNQ score and other radiological parameters on MRI scans. Clinical and functional recovery was evaluated by Lysholm score, Visual Analogues Scale, Tegner activity scale and modified Cincinnati knee rating system at 6, 12 and 60 months after surgery to estimate the predictive value of the radiological parameters for clinical outcomes. Return-to-sport (ACL-RSI) was measured 60 months after surgery.

RESULTS

Three patients had retear of the neo-ligament (two from Auto group and one from Allo group). All the clinical/functional parameters significantly improved over time, with no statistically significant difference between the groups. At 6 months, the SNQ value was significantly higher in the Auto than in the Allo group (12.9 vs 7.9, p = 0.038), but at 12 months they were comparable (9.8 vs 10.4). The 6-month SNQ values did not correlate with the clinical scores, whereas the 12-month SNQ values significantly correlated with the Cincinnati score, Lysholm score and Tegner activity scale collected at 60-month follow-up.

CONCLUSION

No clinical or functional differences have been found between the two treatment groups, supporting the suitability of using allograft in primary ACLR, when available. The results at MRI scans showed a different graft maturation trend in the two groups, with allografts being more reactive in the first 6 months. MRI together with the subjective evaluation allows to evaluate objectively the status of the neo-ligamentization process and therefore helps the surgeon to dictate the individual time for return-to-sport.

LEVEL OF EVIDENCE

Level I.

Comparing the Stiffness of Peroneus Longus Tendon Versus Hamstrings in Anterior Cruciate Ligament Reconstruction: A Biomechanical Study

Background: The use of autografts originating from either hamstring tendons or peroneus longus tendons is a surgical option in anterior cruciate ligament (ACL) reconstruction. Objectives: This research aimed to compare the tensile strength between the hamstring tendon and the peroneus longus tendon in ACL reconstruction. The hypothesis of this study was: Peroneus longus grafts have tensile strength equal to hamstring grafts based on living donor patients. Methods: This cross-sectional study was a biomechanical study examining means and standard deviations (SD) by comparing the tensile strength of peroneus longus tendons and hamstring tendons when used as autograft donors in ACL reconstruction. Results: In this study, 51 patients with reconstructive ACL were enrolled. The mean diameter of the hamstring tendon was 7.86 with SD ± 0.69, while the mean diameter of peroneus longus tendon was 7.67 with SD ± 0.63. The mean diameter of the peroneus longus graft was not significantly different. The mean displacement on the hamstring tendon was 2.44 with SD ± 0.42, while the peroneus longus tendon was 2.06 with SD ± 0.14. The peroneus longus tendon had significantly more tensile strength compared to the hamstring tendon. Conclusions: Diameter of the peroneus longus graft was not significantly different from the hamstring graft. However, the peroneus longus graft had more tensile strength than the hamstring graft based on living donor patients.

ACL Study Group survey reveals the evolution of anterior cruciate ligament reconstruction graft choice over the past three decades

PURPOSE

Anterior cruciate ligament reconstruction (ACLR) aims to restore knee function and stability, allowing patients to return to the activities they enjoy and minimize further injury to the meniscus and cartilage and their ultimate progression to osteoarthritis. This study aims to present the evolution of graft choice over the last three decades according to members of the ACL Study Group (SG).

METHODS

Prior to the January 2020 ACL SG biannual meeting, a survey was administered consisting of 87 questions and 16 categories, including ACLR graft choice. A similar questionnaire has been administered prior to each meeting and survey results from the past 14 meetings (1992 through 2020, excluding 1994) are included in this work. Survey responses are reported as frequencies in percentages to quantify changes in practice over the surgery period.

RESULTS

In 1992, the most frequent graft choice for primary ACLR was bone-patellar tendon-bone (BTB) autograft, at nearly 90%. Hamstring tendon (HT) autografts have increased in popularity, currently over 50%, followed by just under 40% BTB autograft. Recently, quadriceps tendon (QT) autograft has increased in popularity since 2014.

CONCLUSION

Autograft (HT, BTB, QT) is an overwhelming favorite for primary ACLR over allograft. The preference for HT autograft increased over the study period relative to BTB autograft, with QT autograft gaining in popularity in recent years. Graft selection should be individualized for each patient and understanding the global trends in graft choice can help orthopaedic surgeons discuss graft options with their patients and determine the appropriate graft for each case.

LEVEL OF EVIDENCE

Level V, Expert Opinion.

Aseptically Processed Allograft Implantation: A Safe Strategy for Knee Ligament Reconstructions

Postoperative infections after allograft implantation is a major concern in knee ligament reconstructions considering the theoretical risk of disease transmission and its potential severity. Here, we aimed to evaluate the postoperative infection rate after knee ligament reconstructions using aseptically processed allografts, and provide an overview of the allografts use in an academic tertiary hospital. A retrospective study was performed evaluating patients who underwent knee ligament reconstructions using aseptically processed allografts, including primary and revision surgeries, from 2005 to 2018. Demographic data, including the type of knee injury and trauma energy, and postoperative data were collected focusing on postoperative infections. Regarding these infected cases, further analyses were performed considering the presenting signs and symptoms, the isolated microorganism identified in culture, the time between graft implantation and diagnosis of infection (defined as acute, subacute, and late), and the need for graft removal. A total of 180 cases of ligament reconstructions were included. The mean follow-up was 8.2 (range: 2.1-15.6) years and the mean age at surgery was 34.1 (± 11.1) years. A total of 262 allografts were implanted in those 180 cases, 93 (35.5%) as bone plug allografts and 169 (64.5%) as soft tissue allografts. Common surgical indications included multiligament reconstruction (57.2%) and primary anterior cruciate ligament (ACL) reconstruction (15%). Seven cases (3.9%) presented postoperative infections. Knee pain (100%) and swelling (100%) were the most prevalent symptoms. Two cases (28.6%) presented sinus tract. Allografts were removed in two cases, the same cases that presented draining sinus (p = 0.04). High-energy trauma was the only statistically associated factor for infection (p = 0.04). No significant association between infection and the type of allograft (p > 0.99) or sex (p = 0.35) were observed. Four cases (57.1%) had monomicrobial staphylococcal infections. Based on that, the allograft-related infection rate was 1.7% (the remaining three infected cases). Nonirradiated, aseptically processed allografts have a low postoperative infection rate in knee ligament reconstructions, being a safe alternative for surgeries that require additional source, increased variety, and quantity of grafts.

Effect of Demineralized Bone Matrix, Bone Marrow Mesenchymal Stromal Cells, and Platelet-Rich Plasma on Bone Tunnel Healing After Anterior Cruciate Ligament Reconstruction: A Comparative Micro-Computed Tomography Study in a Tendon Allograft Sheep Model

Background:

The effect of demineralized bone matrix (DBM), bone marrow–derived mesenchymal stromal cells (BMSCs), and platelet-rich plasma (PRP) on bone tunnel healing in anterior cruciate ligament reconstruction (ACLR) has not been comparatively assessed.

Hypothesis:

These orthobiologics would reduce tunnel widening, and the effects on tunnel diameter would be correlated with tunnel wall sclerosis.

Study Design:

Controlled laboratory study.

Methods:

A total of 20 sheep underwent unilateral ACLR using tendon allograft and outside-in interference screw fixation. The animals were randomized into 4 groups (n = 5 per group): Group 1 received 4mL of DBM paste, group 2 received 10 million BMSCs in fibrin sealant, group 3 received 12 mL of activated leukocyte-poor platelet-rich plasma, and group 4 (control) received no treatment. The sheep were euthanized after 12 weeks, and micro-computed tomography scans were performed. The femoral and tibial tunnels were divided into thirds (aperture, midportion, and exit), and the trabecular bone structure, bone mineral density (BMD), and tunnel diameter were measured. Tunnel sclerosis was defined by a higher bone volume in a 250-µm volume of interest compared with a 4-mm volume of interest surrounding the tunnel.

Results:

Compared with the controls, the DBM group had a significantly higher bone volume fraction (bone volume/total volume [BV/TV]) (52.7% vs 31.8%; P = .020) and BMD (0.55 vs 0.47 g/cm³; P = .008) at the femoral aperture and significantly higher BV/TV at femoral midportion (44.2% vs 32.9%; P = .038). There were no significant differences between the PRP and BMSC groups versus controls in terms of trabecular bone analysis or BMD. In the controls, widening at the femoral tunnel aperture was significantly greater than at the midportion (46.7 vs 41.7 mm²; P = .034). Sclerosis of the tunnel was common and most often seen at the femoral aperture. In the midportion of the femoral tunnel, BV/TV (r = 0.52; P = .019) and trabecular number (r_S = 0.50; P = .024) were positively correlated with tunnel widening.

Conclusion:

Only DBM led to a significant increase in bone volume, which was seen in the femoral tunnel aperture and midportion. No treatment significantly reduced bone tunnel widening. Tunnel sclerosis in the femoral tunnel midportion was correlated significantly with tunnel widening.

Clinical Relevance:

DBM might have potential clinical use to enhance healing in the femoral tunnel after ACLR.

Clinical outcome after knee ligament reconstruction with tendon allografts

PURPOSE

The purpose of this study is to investigate the clinical outcome for patients after knee ligament reconstructions with allografts at a university hospital.

METHODS

A total of 33 patients received allografts for reconstructive knee surgery between 2007 and 2017. The follow up evaluation consisted of a clinical knee examination including evaluation of range of motion (ROM), lateral and medial laxity, the Lachman test, the Pivot shift test, the sag test, the posterior drawer test and checking for patellofemoral pain. The following patient-reported outcome measures (PROMs) were used; the Lysholm Function Score, the Tegner activity score, and the Knee injury and Osteoarthritis Outcome Score (KOOS).

RESULTS

Twenty-one (64%) patients were available for the follow-up evaluation and the mean follow-up time was 4.8 years. A total of 16 out of 21 patients had multiligament injuries of which the ACL was the ligament most frequently ruptured. At the time of follow-up, 14 out of 16 patients (87%) with ACL injury had Lachman test grade 0 or grade 1 + , and 12 out of 13 (92%) had a pivot shift grade 0 or 1 + . The mean Lysholm Score was 74. All mean KOOS subscale values were ≥ 59 at the follow-up. The preoperative Tegner activity score was 3 (range, 1-6) and 4 (range, 2-6) at follow up. There were no deep postoperative infections. A total of 19 out of 21 patients (90%) reported that they would have undergone surgery again had they known the clinical outcome in advance.

CONCLUSIONS

The patients improved from the preoperative score to the follow-up score in the knee-related Quality of Life (QoL) KOOS subscale. None of the patients were diagnosed with deep postoperative infections.

Autograft versus allograft tenodesis for chronic ankle instability: a single-center retrospective comparative study

Aim: To compare the outcomes of patients who underwent autograft tenodesis with those who underwent allograft tenodesis for the treatment of chronic mechanical ankle instability. Patients & methods: Ten patients who underwent allograft lateral tenodesis were compared with 15 patients who underwent lateral tenodesis using a split peroneus brevis tendon. Patients were followed up after an average time of 10.5 years. Results: No statistically significant differences concerning American Orthopaedic Foot and Ankle Society and Karlsson-Peterson scores were reported (p = n.s.). A reduced average radiographic anterior talar translation was observed in the autograft group compared with the allograft group (1.4 and 4.0 mm respectively, p < 0.001). Conclusion: Both surgical techniques significantly improved subjective and objective outcomes in patients suffering from chronic ankle instability compared with pre-operatory status. Autograft stabilization provided reduced post-operative anterior talar translation compared with allograft tenodesis.

Tissue-Engineered Decellularized Allografts for Anterior Cruciate Ligament Reconstruction

Anterior cruciate ligament (ACL) reconstruction with allografts is limited by high immunogenicity, poor cellularization, and delayed tendon-bone healing. Decellularized tendons (DAs) have been used as bioscaffolds to reconstruct ligaments with variable success. In the study, four kinds of decellularized allogeneic hamstring tendons were prepared and their microstructure and cytocompatibility were examined in vitro. The results showed that decellularized allografts neutralized by 5% calcium bicarbonate had typical reticular and porous microstructures with optical cytocompatibility. Tissue-engineering decellularized allografts (TEDAs) were prepared with the selected decellularized allografts and tendon stem/progenitor cells and used for ACL reconstruction in a rabbit model. Histological staining showed that the TEDAs promoted cellular infiltration and new vessel formation significantly and improved tendon-bone healing moderately compared to decellularized allografts. Better macroscopic scores and biomechanical results were observed in TEDA groups, but there were no significant differences between DA and TEDA groups at months 1, 2, and 3 postoperatively. Immunohistochemical data showed that the tissue-engineering decellularized allografts enhanced the expression of collagen I at each timepoint and collagen III at months 1 and 2. ELISA analysis showed that the tissue-engineering decellularized allografts reduced the secretion of IgE and IL-1β within 1 month and promoted the secretion of IL-2, IL-4, IL-10, and IL-17 after 1 month. The results showed that tissue-engineering decellularized allografts strengthened intra-articular graft remodeling significantly and provided moderate improvements in tendon-bone healing by creating more suitable immune responses than decellularized allografts. The study revealed that tissue-engineering decellularized allografts as a promising option for ACL reconstruction could achieve more favorable outcomes.

Graft choice in combined anterior cruciate ligament and medial collateral ligament reconstruction

There is a concern regarding which grafts should be used in combined anterior cruciate ligament (ACL) and medial collateral ligament (MCL) reconstructions, with a paucity of recommendations focused on this specific topic.

Expert opinions suggest the use of allograft-only reconstructions to limit donor-site morbidity or using at least one allograft and one autograft.

When a hamstring tendon autograft is harvested, techniques that maintain both the integrity of the sartorius fascia and the gracilis are recommended because of the role that the ST-G-S (semitendinosus-gracilis-sartorius) complex plays in valgus stability in the setting of an MCL-deficient knee.

Cite this article: EFORT Open Rev 2020;5:221-225. DOI: 10.1302/2058-5241.5.190049

Long-term arthroscopic assessment of intra-articular allografts for treatment of spontaneous cranial cruciate ligament rupture in the dog

OBJECTIVE

To assess the 12-month survival of intra-articular, decellularized allografts for the treatment of cranial cruciate ligament disease (CCLD) in dogs.

STUDY DESIGN

Prospective case series.

ANIMALS

Twenty client-owned dogs with spontaneous CCL rupture.

METHODS

Affected stifles were treated solely by implantation of an intra-articular, decellularized, deep digital flexor tendon allograft. Functional outcome was evaluated at baseline and at 6 and 12 months after surgery with the Liverpool Osteoarthritis for Dogs questionnaire and force platform gait analysis. At 12 months after surgery, dogs underwent arthroscopy to visually assess the allografts.

RESULTS

Scores on owner questionnaires (improved 62.5%; P = .005) and ground reaction forces (improved 34.4%; P = .017) were improved in all dogs 12 months after surgery. Dogs with an intact graft (IG) were more likely to have a successful outcome compared with dogs with a torn graft (P = .011). According to arthroscopy, 45% of grafts seemed to survive at 12 months after surgery.

CONCLUSION

About half of intra-articular allografts survived 12 months after implantation in CCL-deficient stifles. Dogs with IG had successful outcomes at 12 months after surgery according to assessment by force platform gait analysis.

CLINICAL SIGNIFICANCE

These results preclude immediate clinical application but provide evidence to justify further investigation of intra-articular grafts as a repair option for CLLD.