Donor-site morbidity after harvest of a bone-tendon-bone patellar tendon autograft

Anthropometric Measurements of Hamstring Tendon Graft and Its Predictors in Ligament Reconstruction Surgeries of Knee: An Observational Study

Introduction Hamstring graft use has been in the forefront of ligament reconstruction around the knee. With the increasing number of surgeries, the complications are equally on the rise. One of the detrimental factors for predicting the outcome is the diameter and length of the graft. We did an observational study to find out the relationship of patient factors with the morphometry of the graft.

Materials and Methods Total 484 patients were included in the study. Preoperatively, the age, sex, height, weight, and activity levels of the patients were noted. They were categorized into two major groups: physically active and inactive. The intraoperative measurements of the grafts were recorded. Analysis of variance for comparing the means of multiple groups was used for statistical analysis.

Results Among the total 484 patients, 407 were male and 77 were female. The semitendinosus graft diameter did not show any statistical significance to the age and weight of the patient. The mean graft diameter was highest in the 45 to 49-year age group. The average graft diameter in physically active group was 3.704 mm, and 3.503 mm in the inactive group. This and the height of the patient proved to have statistically significant relation with graft diameter.

Conclusion Physical activity along with the height of the patient must be taken into due consideration before embarking upon ligament reconstruction with hamstring graft in mind, as these two are found to determine the diameter and length of the hamstring graft.

Bone filling decreases donor site morbidity after anterior cruciate ligament reconstruction with bone-patellar tendon-bone autografts

PURPOSE

Bone-patellar tendon-bone (BTB) autograft remains the most widely used graft source for anterior cruciate ligament reconstruction (ACLR). The drawback associated with BTB is increased donor-site morbidity, such as anterior knee pain. The purpose of this study was to evaluate and compare anterior knee pain after refilling the patella bony defect with bone substitute.

METHODS

This is a retrospective analysis of consecutive patients who underwent BTB ACLR at a single institution between January 2015 and December 2020. The cohort was divided into two groups; one in which the patellar bony defect was refilled with bone substitute (Bone Graft group) and another in which this the bony defects were not treated (No Bone Graft group). Demographic variables, reported anterior knee pain, visual analog scale (VAS) score, complications, re-operation, and patient reported outcome measures, such as the IKDC, LYSHOLM and SF-12 scores, were compared between groups.

RESULTS

A total of 286 patients who underwent BTB ACLR were included. The No Bone Graft group included 88 (30.7%) patients and the Bone Graft group included 198 (69.3%) patients. The Bone Graft group had less anterior knee pain at last clinic follow up (33.3% vs. 51.1% p = 0.004) as well as lower VAS anterior knee pain scores (2.18 vs. 3.13, p = 0.004). The Bone Graft group had lower complications rates (21.7% vs 34.1, p = 0.027). No differences were found in the LYSHOLM, IKDC, and SF-12 scores.

CONCLUSION

Bone refilling in BTB ACLR significantly reduces prevalence and severity of anterior knee pain. Larger randomized trials are needed to confirm the benefits of bone refilling in ACLR patients.

LEVEL OF EVIDENCE

Retrospective study-III.

Trans patellar tendon sagittal tibial cut for lateral unicompartmental knee arthroplasty-location of the split- CT simulation study

BACKGROUND

In lateral unicompartmental knee arthroplasty (UKA), a sagittal cut is often performed through the patellar tendon (PT). Although the approach is likely widely used, it has not been described in detail, especially regarding the site of the split. This study aimed to clarify where the split should be made.

METHODS

This single-center retrospective cohort study included 49 consecutive patients and 51 knees with lateral osteoarthritis. Using preoperative computed tomography, we measured the distance from the medial edge of the PT to the intersection of the PT and the sagittal cutting line, defined as a line parallel to the Akagi's line and passing the tip of the lateral tibial spine.

RESULTS

The sagittal cut line passed a mean of 45 ± 11% of the patellar tendon width from the PT medial edge.

CONCLUSIONS

The tendon split should be made just medial to the center of the PT because it is where the sagittal cut line for lateral UKA passes.

Postoperative Pain Is Associated With Psychological and Physical Readiness to Return to Sports One-Year After Anterior Cruciate Ligament Reconstruction

Purpose

To identify whether any patient factors, injury factors, or symptom severity scores are associated with either psychological or physical readiness to return to sport after anterior cruciate ligament reconstruction (ACLR).

Methods

Consecutive patients with an ACL injury that required surgical treatment were included in this study. All patients completed the single-legged hop testing and the Anterior Cruciate Ligament Return to Sport Index (ACL-RSI) at 1 year postoperatively. Multivariable regression analysis models were used to determine whether an independent relationship existed between baseline patient factors (age, sex, BMI, preinjury Marx Activity Score), injury factors (meniscal tear and chondral injury), physical symptoms (Knee Injury and Osteoarthritis Outcome Score [KOOS] for pain and symptoms), and the dependent variables of physical and psychological readiness to return to sport (single-legged hop and ACL-RSI).

Results

Of the 113 patients who were included, 37% were female, and the mean age of our population was 28.2 years (SD = 8.1). Multivariable regression models demonstrated that patient-reported pain symptoms at 1 year postoperatively, as measured by the KOOS pain subscale, was significantly associated with both ACL-RSI score (Beta estimate: 1.11 [95% CI: .62-1.60] P < .001) and the ability to pass the single-legged hop test (OR: 1.07 [95% CI: 1.004-1.142] P = .037).

Conclusions

Patients with higher reported pain levels at 1 year following ACLR have lower psychological and physical readiness to return to sport.

Level of Evidence

Level 3, retrospective cohort study.

Bone Grafting the Patellar Defect After Bone-Patellar Tendon-Bone Anterior Cruciate Ligament Reconstruction Decreases Anterior Knee Morbidity: A Systematic Review

PURPOSE

The aim of this systematic review was to evaluate the impact of bone grafting of patellar defects on reported anterior knee morbidity and subjective outcomes after bone-patellar tendon-bone autograft reconstruction of the anterior cruciate ligament.

METHODS

A systematic electronic search of MEDLINE, Embase, Web of Science, and the Cochrane Library was carried out. All English-language prospective randomized clinical trials published from January 1, 2000, to July 24, 2020, were eligible for inclusion. All studies addressing patellar defect grafting were eligible for inclusion regardless of the timing of surgery, graft type, surgical technique, or rehabilitation protocol.

RESULTS

A total of 39 studies with 1,955 patients were included for analysis. There were 796 patients in the no patellar grafting (NPG) group, with a mean age range of 22.7 to 33.0 years, and 1,159 patients in the patellar grafting (PG) group, with a mean age range of 17.8 to 34.7 years. The visual analog scale pain score ranged from 1.2 to 5.1 in the NPG group compared with 0.3 to 3.7 in the PG group. The proportion of patients with anterior knee pain ranged from 19% to 81% in the NPG group and from 15% to 32% in the PG group. Moderate to severe kneeling pain was reported in 22% to 57% of patients in the NPG group and 10% of those in the PG group. The percentage of patients with at least 3° of extension loss ranged from 4% to 43% in the NPG group and from 2% to 11% in the PG group.

CONCLUSIONS

PG favors decreased anterior knee pain, kneeling pain, and extension loss compared with non-grafted defects; however, the functional outcomes are comparable. Owing to the heterogeneity in reporting, statistical conclusions could not be drawn.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and II studies.

Is there significant regeneration of the hamstring tendons after harvest for ACL reconstruction? A systematic review of literature

BACKGROUND

Regeneration potential of Hamstring tendons after harvest assumes significant clinical relevance as its use has become widespread today. Methods which best assess the regeneration, extent and type of regeneration, plus issues related to functional loss are important for the surgeon to know. This review looks at the literature to find answers to the above questions.

PURPOSE

To summarize the evidence in support of hamstring tendon regeneration, and the most appropriate modality for evaluation of regeneration. Additionally, to evaluate the regeneration in terms of complete or partial, extent and its impact on strength deficit and functional outcomes.

METHODS

We did a systematic review of literature through specified search engines and identified 30 of 285 studies to be relevant (19 prospective and 11 retrospective).

RESULTS

Evaluation of above data suggests tissue regeneration at harvest sites does occur (78.9% of semitendinosus and 42.7% of gracilis tendons), but this regeneration is variable. No established definition of regeneration exists; MRI is an adequate tool to identify regeneration, while biopsy is confirmative. USG is a cost-effective screening method and can document distal progress of regenerate. Semitendinosus and gracilis tendons regenerate at different rates and extents, and often fuse together, but there is no evidence to state that one regenerates better than the other. Proximal retraction of the muscle-tendon junction occurs, along with some atrophy, which affects function to a variable extent. Strength deficits may persist, but they may not convert to significant functional deficits.

CONCLUSION

There is variable hamstring regeneration after harvest, with poorly defined definition of "regeneration". Some changes in the muscle itself, abnormal distal insertion and absence of regeneration in some are documented, along with strength deficits. Although overall functional deficits have been reported to be minimal, a definite change in the anatomy of the medial hamstrings is a factor to be kept in consideration. More information is needed about the long-term consequences.

No Difference in Outcome of Anterior Cruciate Ligament Reconstruction with "Bone-patellar Tendon-bone versus Semitendinosus-gracilis Graft with Preserved Insertion": A Randomized Clinical Trial

BACKGROUND

The type of graft for anterior cruciate ligament (ACL) reconstruction is still a topic of debate and there is still no clear consensus on the ideal graft for ACL reconstruction.

PURPOSE

This study was conducted to compare the outcome of ACL reconstruction surgery between hamstring tendon graft and bone-patellar tendon-bone (BPTB) graft.

MATERIALS AND METHODS

One hundred and sixty professional athletes were enrolled in the study. They were divided into two groups by computerized randomization. In Group I, ACL reconstruction was done using BPTB graft, and in Group II, ACL reconstruction was done using semitendinosus gracilis graft with preserved tibial insertion (STGPI). Postoperatively, patients were assessed for knee stability, Lysholm score, and WOMAC score.

RESULTS

Mean KT-1000 side-to-side difference at 1 year was 2.31 ± 1.68 mm in BPTB cohort and 2.52 ± 1.6 mm in STGPI cohort (P = 0.4); and at 2 years, it was 1.98 ± 1.62 mm in BPTB cohort and 2.23 ± 1.6 mm in STGPI cohort (P = 0.4). Mean Lysholm score at 2 years was 96.1 ± 5.81 in STGPI cohort and 97.3 ± 4.62 in BPTB cohort (P = 0.15). Mean WOMAC score at 2 years was 3.3 ± 2.76 in STGPI cohort and 2.84 ± 2.21 in BPTB cohort (P = 0.25). Graft rupture rate was 3.75%; 3 patients in each group had graft rupture. Kneeling pain was present in 15% (12/80) of patients with BPTB graft whereas none of the patients in STGPI cohort had kneeling pain.

CONCLUSION

There was no difference between two grafts in term of knee stability, visual analog scale score and functional outcome. However, hamstring tendon graft is associated with less donor site morbidity.

Beta-Tricalcium Phosphate Block for Donor Site Morbidity of the Patella in Anterior Cruciate Ligament Reconstruction Using Bone-Patellar Tendon-Bone Graft

Purpose

This study aimed to investigate anterior knee symptoms in patients who underwent anterior cruciate ligament (ACL) reconstruction using bone-patellar tendon-bone (BPTB) graft followed by implantation of a beta-tricalcium phosphate (β-TCP) block as a bone void filler.

Materials and Methods

We retrospectively reviewed 84 cases of synthetic bone grafting using a β-TCP block for the patellar bone defect in ACL reconstruction with a BPTB autograft. Computed tomography of the operated knee was performed immediately after the surgery to evaluate whether the grafted β-TCP block protruded forward from the anterior surface of the patella. On the basis of the results, the cases were divided into a protrusion group (n=31) and a non-protrusion group (n=53). Anterior knee symptoms at 12 months postoperatively and absorption of the grafted β-TCP block were compared between the two groups.

Results

Except for patellofemoral crepitus, there was no significant difference in anterior knee symptoms between the two groups (p>0.05). The incidence of patellofemoral crepitus was significantly lower in the protrusion group than in the non-protrusion group (p=0.027). The groups showed no significant difference in β-TCP absorption.

Conclusions

The present study demonstrated that the protrusion of β-TCP that was used as a bone void filler had no adverse effects.

Isokinetic flexion strength recovery after ACL reconstruction: a comparison between all inside graft-link technique and full tibial tunnel technique

INTRODUCTION

Recently, a new minimally invasive single bundle technique for anatomic ACL reconstruction has been described, called the 'All-Inside graft-link technique'. One of the advantages of this procedure is the reduced morbidity at the donor site as the graft choice is the quadrupled semitendinosus, thus sparing the gracilis tendon. The aim of this study was to evaluate isokinetic flexion strength recovery in patients who underwent a gracilis sparing technique compared to those with a full-tibial tunnel technique using a doubled gracilis and semitendinosus tendons (DGST) graft.

METHODS

Patients were divided into two groups: Group A (22 patients) who underwent ACL reconstruction performed with an All-Inside graft-link technique; Group B (22 patients) who underwent ACL reconstruction with an Out-In technique and DGST graft. At a mean follow-up of 13 months, quadriceps and hamstring isokinetic peak torque deficits were recorded.

RESULTS

In group A, the mean side to side peak torque flexion difference between the operated and non-operated limbs was -3% and the mean torque at 30° was -7.5% at high angular velocity (180°/sec); the mean peak flexion torque was 7.2% and the mean torque at 30° was 3.1% at low angular velocity (60°/sec). In group B, the mean side to side peak flexion torque was -3.5% and the mean torque at 30° was -7.6% at high angular velocity (180°/sec); the mean peak flexion torque was -7.2% and the mean torque at 30° was -11% at low angular velocity (60°/sec). A statistically significant difference was found between the two groups at lower angular velocity both for the mean peak flexion torque and the mean torque at 30° (p = 0.009), with better results in the study group.

DISCUSSION/CONCLUSION

Gracilis sparing technique is a minimally invasive technique for ACL reconstruction and yielded a significantly better flexion strength recovery at lower angular velocity compared to a full tibial tunnel technique with DGST for ACL reconstruction.

Ceramic Bone Graft Substitutes do not reduce donor-site morbidity in ACL reconstruction surgeries: a pilot study

INTRODUCTION

Anterior knee pain is a major problem following Bone-patellar-tendon-bone graft (BPTB) use in anterior cruciate ligament (ACL) reconstruction. We hypothesized that filling the donor defect sites with bone-graft substitute would reduce the anterior knee symptoms in ACL reconstruction surgeries.

MATERIAL AND METHODS

Patients operated for ACL-deficient knee between March 2012 and August 2013 using BPTB graft were divided into two treatment groups. The patellar and tibial donor-site bony defects were filled-up with Hydroxyapatite-Bioglass (HAP:BG) blocks in the study group (n = 15) and no filler was used in the control group (n = 16). At 2 years, the clinical improvement was assessed using International Knee Documentation Committee (IKDC) score and donor-site morbidity was assessed by questionnaires and specific tests related to anterior knee pain symptoms.

RESULTS

Donor-site tenderness was present in 40% patients in the study group and 37.5% patients in the control group (p = 0.59). Pain upon kneeling was present in 33.3% patients in the study group and 37.5% patients in the control group (p = 0.55). Walking in kneeling position elicited pain in 40% patients in the study group and 43.8% in the control group (p = 0.56). The mean visual analogue score for knee pain was 3.0 in the study group and 3.13 in the control group, with no statistically significant difference (p = 0.68). Unlike control group, where a persistent bony depression defect was observed at donor sites, no such defects were observed in the study group.

CONCLUSION

Filling the defects of donor sites with HAP:BG blocks do not reduce the anterior knee symptoms in patients with ACL reconstruction using autogenous BPTB graft.

No Difference in Outcome of Anterior Cruciate Ligament Reconstruction with "Bone-patellar Tendon-bone versus Semitendinosus-gracilis Graft with Preserved Insertion:" A Randomized Clinical Trial

BACKGROUND

The type of graft for anterior cruciate ligament (ACL) reconstruction is still a topic of debate and there is still no clear consensus on the ideal graft for ACL reconstruction.

PURPOSE

This study was conducted to compare the outcome of ACL reconstruction surgery between hamstring tendon graft and bone-patellar tendon-bone (BPTB) graft.

MATERIALS AND METHODS

One hundred and sixty professional athletes were enrolled in the study. They were divided into two groups by computerized randomization. In Group I, ACL reconstruction was done using BPTB graft, and in Group II, ACL reconstruction was done using semitendinosus gracilis graft with preserved tibial insertion (STGPI). Postoperatively, patients were assessed for knee stability, Lysholm score, and WOMAC score.

RESULTS

Mean KT-1000 side-to-side difference at 1 year was 2.31 ± 1.68 mm in BPTB cohort and 2.52 ± 1.6 mm in STGPI cohort (P = 0.4); and at 2 years, it was 1.98 ± 1.62 mm in BPTB cohort and 2.23 ± 1.6 mm in STGPI cohort (P = 0.4). Mean Lysholm score at 2 years was 96.1 ± 5.81 in STGPI cohort and 97.3 ± 4.62 in BPTB cohort (P = 0.15). Mean WOMAC score at 2 years was 3.3 ± 2.76 in STGPI cohort and 2.84 ± 2.21 in BPTB cohort (P = 0.25). Graft rupture rate was 3.75%; 3 patients in each group had graft rupture. Kneeling pain was present in 15% (12/80) of patients with BPTB graft whereas none of the patients in STGPI cohort had kneeling pain.

CONCLUSION

There was no difference between two grafts in term of knee stability, visual analog scale score and functional outcome. However, hamstring tendon graft is associated with less donor site morbidity.

Complications following harvesting of patellar tendon or hamstring tendon grafts for anterior cruciate ligament reconstruction: Systematic review of literature

Anterior cruciate ligament (ACL) reconstruction can be performed with an autograft, which is most often harvested from the patient's hamstring tendon (HT) or patellar tendon (PT). However, autograft harvesting leads to morbidity that is by no means insignificant. A systematic review of literature was performed to define the incidence of complications related to graft harvesting and the methods to prevent these complications. In March 2017, a systemic review of literature was performed using the keywords"harvesting", "harvest", "morbidity", "complication", "cruciate ligament". No time limit was applied. The studies had to be written in French or English with their abstract available online. This initial search based on the title and abstract identified 133 articles. Two independent observers analyzed each article entirely, including the references. In all, 36 articles were retained. The main complication of HT harvesting was sensory deficit because of damage to the infrapatellar branches of the saphenous nerve. This complication occurred in 39.7% to 88% of patients. This risk can be reduced by using a horizontal or oblique incision. The main complication following PT harvesting is anterior knee pain, reported in up to 46% of patients. There are substantial numbers of short-, medium- and long-term complications related to the harvesting of the two main ACL autografts. Effective means of prevention exist to reduce the risk of these complications.

LEVEL OF EVIDENCE

II Systematic review of literature.

Use of Pig as a Model for Mesenchymal Stem Cell Therapies for Bone Regeneration

Bone is a plastic tissue with a large healing capability. However, extensive bone loss due to disease or trauma requires extreme therapy such as bone grafting or tissue-engineering applications. Presently, bone grafting is the gold standard for bone repair, but presents serious limitations including donor site morbidity, rejection, and limited tissue regeneration. The use of stem cells appears to be a means to overcome such limitations. Bone marrow mesenchymal stem cells (BMSC) have been the choice thus far for stem cell therapy for bone regeneration. However, adipose-derived stem cells (ASC) have similar immunophenotype, morphology, multilineage potential, and transcriptome compared to BMSC, and both types have demonstrated extensive osteogenic capacity both in vitro and in vivo in several species. The use of scaffolds in combination with stem cells and growth factors provides a valuable tool for guided bone regeneration, especially for complex anatomic defects. Before translation to human medicine, regenerative strategies must be developed in animal models to improve effectiveness and efficiency. The pig presents as a useful model due to similar macro- and microanatomy and favorable logistics of use. This review examines data that provides strong support for the clinical translation of the pig model for bone regeneration.

Induced Remodeling of Porcine Tendons to Human Anterior Cruciate Ligaments by α-GAL Epitope Removal and Partial Cross-Linking

This review describes a novel method developed for processing porcine tendon and other ligament implants that enables in situ remodeling into autologous ligaments in humans. The method differs from methods using extracellular matrices (ECMs) that provide postoperative orthobiological support (i.e., augmentation grafts) for healing of injured ligaments, in that the porcine bone-patellar-tendon-bone itself serves as the graft replacing ruptured anterior cruciate ligament (ACL). The method allows for gradual remodeling of porcine tendon into autologous human ACL while maintaining the biomechanical integrity. The method was first evaluated in a preclinical model of monkeys and subsequently in patients. The method overcomes detrimental effects of the natural anti-Gal antibody and harnesses anti-non-gal antibodies for the remodeling process in two steps: Step 1. Elimination of α-gal epitopes—this epitope that is abundant in pigs (as in other nonprimate mammals) binds the natural anti-Gal antibody, which is the most abundant natural antibody in humans. This interaction, which can induce fast resorption of the porcine implant, is avoided by enzymatic elimination of α-gal epitopes from the implant with recombinant α-galactosidase. Step 2. Partial cross-linking of porcine tendon with glutaraldehyde—this cross-linking generates covalent bonds in the ECM, which slow infiltration of macrophages into the implant. Anti-non-gal antibodies are produced in recipients against the multiple porcine antigenic proteins and proteoglycans because of sequence differences between human and porcine homologous proteins. Anti-non-gal antibodies bind to the implant ECM, recruit macrophages, and induce the implant destruction by directing proteolytic activity of macrophages. Partial cross-linking of the tendon ECM decreases the extent of macrophage infiltration and degradation of the implant and enables concomitant infiltration of fibroblasts that follow the infiltrating macrophages. These fibroblasts align with the implant collagen fibers and secrete their own collagen and other ECM proteins, which gradually remodel the porcine tendon into human ACL. This ligamentization process lasts ∼2 years and the biomechanical integrity of the graft is maintained throughout the whole period. These studies are the first, and so far the only, to demonstrate remodeling of porcine tendon implants into permanently functional autologous ACL in humans.

Morphologic Characteristics and Strength of the Hamstring Muscles Remain Altered at 2 Years After Use of a Hamstring Tendon Graft in Anterior Cruciate Ligament Reconstruction

BACKGROUND

The hamstring tendon graft used in anterior cruciate ligament (ACL) reconstruction has been shown to lead to changes to the semitendinosus and gracilis musculature.

HYPOTHESIS

We hypothesized that (1) loss of donor muscle size would significantly correlate with knee muscle strength deficits, (2) loss of donor muscle size would be greater for muscles that do not experience tendon regeneration, and (3) morphological adaptations would also be evident in nondonor knee muscles.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Twenty participants (14 men and 6 women, mean age 29 ± 7 years, mean body mass 82 ± 15 kg) who had undergone an ACL reconstruction with a hamstring tendon graft at least 2 years previously underwent bilateral magnetic resonance imaging and subsequent strength testing. Muscle and tendon volumes, peak cross-sectional areas (CSAs), and lengths were determined for 12 muscles and 6 functional muscle groups of the surgical and contralateral limbs. Peak isokinetic concentric strength was measured in knee flexion/extension and internal/external tibial rotation.

RESULTS

Only 35% of the patients showed regeneration of both the semitendinosus and gracilis tendons. The regenerated tendons were longer with larger volume and CSA compared with the contralateral side. Deficits in semitendinosus and gracilis muscle size were greater for muscles in which tendons did not regenerate. In addition, combined hamstring muscles (semitendinosus, semimembranosus, and biceps femoris) and combined medial knee muscles (semitendinosus, semimembranosus, gracilis, vastus medialis, medial gastrocnemius, and sartorius) on the surgical side were reduced in volume by 12% and 10%, respectively. A 7% larger volume was observed in the surgical limb for the biceps femoris muscle and corresponded with a lower internal/external tibial rotation strength ratio. The difference in volume, peak CSA, and length of the semitendinosus and gracilis correlated significantly with the deficit in knee flexion strength, with Pearson correlations of 0.51, 0.57, and 0.61, respectively.

CONCLUSION

The muscle-tendon properties of the semitendinosus and gracilis are substantially altered after harvesting, and these alterations may contribute to knee flexor weakness in the surgical limb. These deficits are more pronounced in knees with tendons that do not regenerate and are only partially offset by compensatory hypertrophy of other hamstring muscles.

Pain in donor site after BTB-ACL reconstruction with PRGF: a randomized trial

INTRODUCTION

Anterior cruciate ligament (ACL) tears are highly incident injuries in young athletes within our work area. The use of the patellar graft, despite being the treatment of choice, presents post-operative problems such as anterior knee pain, which limits its use and leads to preference being taken for alternative grafts. Our aim was to evaluate if the application of PRGF reduces anterior knee pain in donor site in BTB-ACL reconstruction.

MATERIALS AND METHODS

43 patients were included in the double-blinded and randomized clinical trial comparing two patient groups who underwent ACL reconstruction using patellar tendon graft, comparing anterior knee pain with and without the application of PRGF at the donor site after harvesting the graft.

RESULTS

The PRGF group showed decreased donor site pain in comparison to the control group, with significant differences in the first two months of follow-up.

CONCLUSION

The application of PRGF decreased donor site pain compared to the control group.

Anterior cruciate ligament reconstruction with a novel porcine xenograft: the initial Italian experience

At the current state of the art in anterior cruciate ligament (ACL) reconstruction, multiple techniques have been presented but none has given clearly defined and improved results. One of the main issues concerns the choice of graft. The concept of using xenograft tissue, defined as a graft tissue from one species and destined for implantation in an unlike species, was introduced in order to try to overcome the mechanical and biological concerns associated with synthetic materials and the safety and quality concerns and availability problems of allograft tissue. Xenograft tissue carries the risk of producing an immunological reaction. In order to try to overcome or attenuate the immune response against porcine xenograft tissue, the Z-Process® (Aperion Biologics Inc, San Antonio, Texas, USA) has been developed and used to produce the Z-Lig® family of devices for ACL reconstruction procedures. Z-Lig® is a tendon graft with or without bone blocks, sourced from animal tissue in a manner consistent with what has normally been sourced from human tissue, and processed to overcome anti-Gal-mediated rejection and to attenuate other immunological recognition in humans. All this while ensuring sterility, viral inactivation and preservation of mechanical proprieties appropriate for an ACL reconstruction device. The Z-Lig® device has been tested in skeletally mature monkeys and given interesting and promising results from the preclinical performance and safety profile point of view. On this basis, it was possible to proceed with the first clinical trial involving humans, which gave similar encouraging results. The Z-Lig® device has also been implanted in Italy at the Rizzoli Orthopaedic Institute in Bologna, as a part of international multicenter prospective randomized blinded controlled study aimed at comparing xenograft with allograft tissue.

Preservation of hamstring tibial insertion in anterior cruciate ligament reconstruction: a review of the current literature

Hamstring graft (HG) used in anterior cruciate ligament (ACL) reconstruction undergoes a biological modification process called "ligamentization" in the early postoperative period that proceeds through three different phases: an early graft-healing phase with central graft necrosis, a phase of proliferation, and finally, a ligamentization phase toward the properties of the intact ACL. The fastening of this process could result in more aggressive rehabilitation protocols as well as faster sport resumption. A recent literature supports the preservation of HG tibial attachment in order to enhance "ligamentization" process. Aim of this literature review is to describe all the techniques described that spare HG tibial insertion and the obtained results in order to evaluate evidence that would substantiate the maintenance of HG tibial insertion in ACL reconstruction. A search was performed using the following keywords "ACL reconstruction" in combination with "hamstrings," "hamstrings insertion," "tibial insertion," "ligamentization," and "over the top"; 18 articles were found to be relevant. Among these, eight randomized clinical trials (RCTs) were found. The RCT analyzed presented a high number of biases regarding the analyzed topic, thus making impossible to draw definitive evidences to validate HG tibial insertion sparing in ACL reconstruction. Despite the satisfactory results in many clinical series and the promising results in anatomic and animal studies, well-designed prospective clinical trials with large cohort of patients associated with MRI evaluation are mandatory to assess the beneficial effects of HG attachment preservation in ACL reconstruction.

Hamstring Tendon Regeneration After Harvest for Anterior Cruciate Ligament Reconstruction: A Systematic Review

PURPOSE

To assess whether the portions of the semitendinosus and gracilis tendons harvested for anterior cruciate ligament reconstruction have the potential to regenerate and, if so, to evaluate the histologic properties and actual function of this newly formed tissue.

METHODS

We performed a comprehensive search of CINAHL (Cumulative Index to Nursing and Allied Health Literature), Embase, Medline, the Cochrane Central Registry of Controlled Trials, and SPORTDiscus from inception of the databases to July 2014, using various combinations of keywords. Studies focusing on hamstring tendon and muscle regeneration through imaging and histology, as well as on the related functional outcomes, were selected. We included studies assessing evidence of tissue regeneration with imaging (magnetic resonance imaging, 3-dimensional computed tomography, ultrasonography) or with histologic examination of biopsy samples (or a combination thereof).

RESULTS

Nineteen articles were included in this review, with a total of 400 patients observed. The overall rate of tissue regeneration was 86.0%, with similar values shown in most studies regardless of the methodology of the assessment. Biopsy confirmed that the tissue found at the site in 74% of the cases showed typical histologic features of the tendon. The mean modified Coleman Methodology Score of the studies included was 52.7 points, showing a modest methodologic quality for the studies published to date.

CONCLUSIONS

In over 85% of the cases analyzed, regeneration signs of the harvested tendon were found through different imaging and histologic methodologies. A torque deficit in deep knee flexion is always present postoperatively, but the cause for this is still unclear. There is a need for better-designed trials featuring a higher level of evidence to further investigate this matter, and the effects of postoperative care and the surgical approach used on the regeneration process should be analyzed in the future.

LEVEL OF EVIDENCE

Level IV, systematic review of Level II, III, and IV studies.

Healing of donor site in bone-tendon-bone ACL reconstruction accelerated with plasma rich in growth factors: a randomized clinical trial

PURPOSE

To determine whether the use of plasma rich in growth factors accelerates healing of the donor site in bone-tendon-bone anterior cruciate ligament (ACL) reconstruction (patellar graft). The use of the patellar graft presents post-operative problems such as anterior knee pain, which limits its use and leads to preference being taken for alternative grafts.

METHODS

A double-blind, randomized, clinical trial was performed comparing two groups of patients who underwent ACL reconstruction using patellar tendon graft and comparing the use of plasma rich in growth factors at the donor site after graft harvest in terms of local regeneration by ultrasound assessment.

RESULTS

The plasma rich in growth factors group shows earlier donor site regeneration in comparison with the control group (2 months earlier), with significant differences in the first 4 months of the follow-up.

CONCLUSION

The application of plasma rich in growth factors shows accelerated tissue regeneration processes with respect to the control group. This fact, together with the previously published with similar conclusions, can create a knowledge basis in order to set out new recovery guidelines following ACL reconstruction.

LEVEL OF EVIDENCE

Therapeutic study, Level I.

Closure of patellar tendon defect in anterior cruciate ligament reconstruction with bone-patellar tendon-bone autograft: systematic review of randomized controlled trials

PURPOSE

This study aimed to systematically review the highest level of evidence on anterior cruciate ligament (ACL) reconstruction with bone-patellar tendon-bone (BPTB) autografts with patellar tendon defect closure versus no closure after surgery.

METHODS

We performed a systematic review of multiple medical databases using Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Level I and Level II randomized controlled trials comparing patellar tendon defect closure to no closure during ACL reconstruction with BPTB autografts were included. Two independent reviewers analyzed all studies. Descriptive statistics were calculated. Study methodological quality was analyzed using the Modified Coleman Methodology Score (MCMS) and Jadad scale.

RESULTS

Four studies with a combined 221 patients (154 male patients and 67 female patients) with an average age of 26.6 ± 2.4 years (range, 17 to 54 years) were included. All studies randomized patients before surgery into ACLR with BPTB autografts either with patellar tendon defect closure or without closure. There were no differences in clinical outcomes (Lysholm score, Tegner scale, International Knee Documentation Committee [IKDC] classification, modified Larsen score, and Lauridsen rating) between groups. There were no significant differences in knee pain between groups. All studies reported imaging findings of the patellar tendon defect, with 2 studies showing no difference in appearance between groups, one study showing excessive scar formation with defect repair, and one study showing improved restoration of normal tendon appearance with defect repair. The overall quality of the studies was poor, with all studies scoring less than 46 (average, 40.5 ± 4.7) on the MCMS and scoring 1 on the Jadad scale.

CONCLUSIONS

Based on this systematic review of 4 randomized trials, there are no statistically significant or clinically relevant differences in outcomes between patients who have the patellar tendon defect closed and those who have it left open after ACLR with BPTB autografts. The methodology of the included studies limits the interpretation of the data, as evidenced by low MCMS and Jadad scores.

LEVEL OF EVIDENCE

Level II, systematic review of Level I and Level II studies.

From design of bio-based biocomposite electrospun scaffolds to osteogenic differentiation of human mesenchymal stromal cells

Electrospinning coupled with electrospraying provides a straightforward and robust route toward promising electrospun biocomposite scaffolds for bone tissue engineering. In this comparative investigation, four types of poly(3-hydroxybutyrate) (PHB)-based nanofibrous scaffolds were produced by electrospinning a PHB solution, a PHB/gelatin (GEL) mixture or a PHB/GEL/nHAs (hydroxyapatite nanoparticles) mixed solution, and by electrospinning a PHB/GEL solution and electrospraying a nHA dispersion simultaneously. SEM and TEM analyses demonstrated that the electrospun nHA-blended framework contained a majority of nHAs trapped within the constitutive fibers, whereas the electrospinning-electrospraying combination afforded fibers with a rough surface largely covered by the bioceramic. Structural and morphological characterizations were completed by FTIR, mercury intrusion porosimetry, and contact angle measurements. Furthermore, an in vitro investigation of human mesenchymal stromal cell (hMSC) adhesion and proliferation properties showed a faster cell development on gelatin-containing scaffolds. More interestingly, a long-term investigation of hMSC osteoblastic differentiation over 21 days indicate that hMSCs seeded onto the nHA-sprayed scaffold developed a significantly higher level of alkaline phosphatase activity, as well as a higher matrix biomineralization rate through the staining of the generated calcium deposits: the fiber surface deposition of nHAs by electrospraying enabled their direct exposure to hMSCs for an efficient transmission of the bioceramic osteoinductive and osteoconductive properties, producing a suitable biocomposite scaffold for bone tissue regeneration.

Autologous platelet-rich plasma gel to reduce donor-site morbidity after patellar tendon graft harvesting for anterior cruciate ligament reconstruction: a randomized, controlled clinical study

PURPOSE

Bone-patellar tendon-bone technique (BPTB) for anterior cruciate ligament injuries is associated with a higher risk of donor-site morbidity. To evaluate whether platelet-rich plasma (PRP), due to its anti-inflammatory properties and capacity to stimulate tissue regeneration, was able to reduce the anterior knee pain, the kneeling pain, and donor-site morbidity, as evidenced by evaluation of VISA and VAS scoring scales and MRI analysis of the tendon and bone defect, we performed a clinical randomized controlled study where PRP gel was applied to donor site after ACL reconstruction with BPTB.

METHODS

Forty young athletes with the indication of ACL reconstruction with patellar tendon grafts were randomly assigned to group A (n = 20 patients, control group) or group B (n = 20 patients, PRP group). The autologous PRP gel was applied to both the patellar and tendon bone plug harvest site and stabilized by the peritenon suture. At 12-month follow-up, all patients underwent clinical examination and VAS and VISA questionnaires, respectively, evaluating the average daily pain of the knee and the pain during particular activities involving the knee, were filled. MRI at the same time point was also performed.

RESULTS

VISA scores were significantly higher in the patients treated with PRP (84.5 ± 11.8 and 97.8 ± 2.5 for group A and for group B; P = 0.041), whereas no significant difference in postoperative VAS scores between the two groups was observed (1 ± 1.4 and 0.6 ± 0.9 for group A and group B, n.s.). In 85% of PRP group patients, the tibial and patellar bone defect was satisfactorily filled by new bony tissue (>70% of bone gap filled), whereas this percentage was just of 60% in control group patients, but this difference was not statistically significant.

CONCLUSIONS

The study shows the usefulness of PRP in reducing subjective pain at the donor-site level after ACL reconstruction with BPTB. However, this approach deserves further investigations to confirm PRP efficacy and to elucidate its mechanism of action.

LEVEL OF EVIDENCE

Prospective randomized controlled study, Level I.

ACL reconstruction using bone-tendon-bone graft engineered from the semitendinosus tendon by injection of recombinant BMP-2 in a rabbit model

We attempted to generate a bone-tendon-bone structure by injecting human-type recombinant human bone morphogenetic protein-2 (rhBMP-2) into the semitendinosus tendon, and an anterior cruciate ligament (ACL) defect was reconstructed by grafting the engineered bone-tendon-bone graft. Two ossicles with a separation distance of 1 cm were generated within the left semitendinosus tendon of a rabbit 6 weeks after the injection of rhBMP-2 (15 µg at each site). The engineered bone-tendon-bone graft was transplanted in order to reconstruct the ACL by passing the graft through the bone tunnels. In the control group, the ACL was reconstructed with the semitendinosus tendon without BMP-2 using the same methods as those used in the experimental group. The animals were harvested at 4 or 8 weeks after surgery and examined by radiographic, histological, and biomechanical methods. In the experimental group, ossicles in the bone-tendon-bone graft were successfully integrated into the host bone of the femur and tibia. Histological analysis revealed that characteristic features identical to the normal direct insertion morphology had been restored. Biomechanical pull-out testing showed that the ultimate failure load and stiffness of the reconstructed ACL in the experimental group were significantly higher than those in the control group at both 4 and 8 weeks (p < 0.05). These results indicate the potential of regenerative reconstruction of the ACL, and the reconstruction resulted in the restoration of morphology and function equivalent to those of the normal ACL.

Precipitation of nanohydroxyapatite on PLLA/PBLG/Collagen nanofibrous structures for the differentiation of adipose derived stem cells to osteogenic lineage

Tissue engineering and nanotechnology have enabled engineering of nanostructured materials to meet the current challenges in bone treatment owing to rising occurrence of bone diseases, accidental damages and defects. Poly(L-lactic acid)/Poly-benzyl-L-glutamate/Collagen (PLLA/PBLG/Col) scaffolds were fabricated by electrospinning and nanohydroxyapatite (n-HA) was deposited by calcium-phosphate dipping method for bone tissue engineering (BTE). The abundance and accessibility of adipose derived stem cells (ADSC) may prove to be novel cell therapeutics for bone repair and regeneration. ADSCs were cultured on these scaffolds and were induced to undergo osteogenic differentiation in the presence of PBLG/n-HA for BTE. The cell-biomaterial interactions were analyzed using cell proliferation, SEM and CMFDA dye extraction techniques. Osteogenic differentiation of ADSC was confirmed using alkaline phosphatase activity (ALP), mineralization (ARS) and dual immunofluorescent staining using both ADSC marker protein and Osteocalcin, which is a bone specific protein. The utmost significance of this study is the bioactive PBLG/n-HA biomolecule introduced on the polymeric nanofibers to regulate and improve specific biological functions like adhesion, proliferation and differentiation of ADSC into osteogenic lineage. This was evident from the immunostaining and CMFDA images of ADSCs showing cuboidal morphology, characteristic of osteogenic lineage. The observed results proved that the PLLA/PBLG/Col/n-HA scaffolds promoted greater osteogenic differentiation of ADSC as evident from the enzyme activity and mineralization profiles for bone tissue engineering.

The effects of hamstring harvesting on outcomes in anterior cruciate ligament-reconstructed patients: a comparative study between hamstring-harvested and -unharvested patients

PURPOSE

The purpose of this study was to evaluate the effects of hamstring harvesting in patients after anterior cruciate ligament (ACL) reconstruction by comparing groups with and without hamstring harvesting.

METHODS

We evaluated the effect of hamstring harvesting in 73 consecutive patients who underwent ACL reconstruction: 39 patients whose hamstrings were harvested for autografts (group H) were compared with 34 patients who received allografts during the same time period (group C [control]). The cases and controls were compared by analyzing the following variables: age, height, weight, mean follow-up period, type of tissue used, and meniscal surgery. Outcomes were assessed by the Lysholm knee score, Tegner activity score, and KT-2000 side-to-side difference (MEDmetric, San Diego, CA), as well as functional performance tests. The flexor deficit and isokinetic peak torque for knee flexion were measured in the sitting position (0° to 90°), and the flexion torque at 90° was measured in the prone position (60° to 120°).

RESULTS

Although significant knee flexion weakness after ACL reconstruction was observed, a significantly greater knee flexor deficit was found in autograft patients than in allograft patients (P < .001). No differences were found between groups in terms of clinical and functional results regardless of hamstring harvesting. The performance of both study groups in all 4 functional tests were significantly correlated with flexor deficit in the sitting position (P < .05) but not in hyperflexion. Significant flexor deficits in both normal and hyperflexed positions were noted in both groups when compared with the unaffected knee (group H, P < .001; group C, P = .002).

CONCLUSIONS

These results indicate significant knee flexion weakness compared with the unaffected knee after ACL reconstruction regardless of hamstring harvesting. Moreover, the greater increase in knee flexor deficit in the hamstring-harvested group compared with the allograft group was statistically significant. However, clinical and functional outcomes were similar between the groups.

LEVEL OF EVIDENCE

Level III, case-control study.

[Late patellar tendon rupture 10 years after anterior cruciate ligament reconstruction using a bone-patellar tendon-bone graft]

Autologous transplantation of the central third of the patella tendon with a bone-patellar tendon-bone (BTB) graft is one of the most commonly used techniques for anterior cruciate ligament (ACL) reconstruction. Frequently chosen alternative sources include semitendinosus and gracilis tendon autografts. The differences of opinion regarding graft sources mainly result from comparison of outcome and complications. Although higher donor site morbidity and postoperative extensor mechanism complications are postulated for bone-patellar tendon-bone grafts, patellar tendon ruptures following anterior cruciate ligament reconstruction are rarely reported in the literature. These predominantly occur during the early postoperative period. We present the case of a patellar tendon rupture in a healthy 36-year-old man, who suffered a skiing accident 10 years after uneventful ACL reconstruction with a BTB graft.

Anterior cruciate ligament reconstruction: outcome using a patellar tendon bone (PTB) autograft (one bone block technique)

OBJECTIVE

The aim of this study was to determine the outcome of anterior cruciate ligament (ACL) reconstruction using a patellar tendon bone autograft (one bone block technique).

METHOD

We retrospectively evaluated a case series of patients who had received arthroscopic ACL reconstructions using patellar tendon bone autograft. Fifty-four (54) ACL reconstructions were evaluated at a mean of 38 months (range 25-62 months). Clinical assessment was made using a modified Lysholm score, documentation of International Kappanee Documentation Committee (lKappaDC), the anterior knee pain questionnaire of Shelbourne and Trumper, and by KappaTau-Rolimeter arthrometric analysis. Radiographic assessments were also performed.

RESULTS

Arthrometric analysis showed that 51 knees (94%) were graded Alpha or Beta with a median laxity of 2 mm, postoperatively. The Lysholm score improved postoperatively from 70 to 89. The patellar position in terms of congruence angle did not show any significant change, and the final shortening of the patellar tendon using the Insall-Salvati ratio was 6.07%. Only three patients complained of moderate pain on kneeling, one patient was unable to participate in strenuous works and one patient complained of harvest-site tenderness.

CONCLUSION

It is concluded that the use of patellar tendon autograft with a single tibial-tubercule bone block and a strip of patellar periosteum have the advantages of being available and comparable in terms of graft size and strength and shows satisfactory results with reduced anterior knee pain.

Bone-patella tendon-bone autograft anterior cruciate ligament reconstruction

The anterior cruciate ligament (ACL) serves an important stabilizing and biomechanical function for the knee. Reconstruction of the ACL remains one of the most commonly performed procedures in the field of sports medicine. Reconstruction of the ACL with bone-patella tendon-bone (BPTB) autograft secured with interference screw fixation has been the historical reference standard and remains the benchmark against which other methods are gauged. This article reviews the reconstruction of the ACL with BPTB autograft including the surgical technique, rationale for BTPB use, and outcomes.

Generation of tendon-to-bone interface "enthesis" with use of recombinant BMP-2 in a rabbit model

The anatomical structure at bone-tendon and bone-ligament interfaces is called the enthesis. Histologically, the enthesis is characterized by a transitional series of tissue layers from the end of the tendon to bone, including tendon, fibrocartilage, calcified fibrocartilage, and bone. This arrangement yields stronger direct connection of the soft tissues to bone. In surgical repair, the enthesis has proven difficult to reproduce, and the success of ligament-bone bonding has depended on the fibrous attachment that forms after any ligament reconstructions. In this study, we attempted to generate a direct-insertion enthesis in two stages. First, recombinant human bone morphogenetic protein-2 (rhBMP-2) was injected into the flexor digitorum communis tendon in the rabbit hind limb to induce ectopic ossicle formation. In a second step, the resultant tendon/ossicle complex was then surgically transferred onto the surface of the rabbit tibia to generate a stable tendon-bone junction. One month following surgery, histomorphological examination confirmed direct insertion of tendon-bone structures in the proximal tibia of the rabbit. Ultimate failure loads of the BMP-2-generated tendon-bone junction were significantly higher than in the control group (p < 0.01). These findings suggest that it is possible to successfully regenerate a direct tendon-to-bone enthesis. Use of this approach may enable successful reconstruction of joints rendered unstable after ligamentous rupture or laxity after anterior cruciate ligament injury.

ACL reconstruction with semitendinosus tendon autograft without detachment of its tibial insertion: a histologic study in a rabbit model

The purpose of this study was to evaluate the histologic changes that occur between 3 and 12 weeks in an intra-articular, semitendinosus autograft, which was harvested without detachment of its tibial insertion and was placed through tibial and femoral drill holes, in a rabbit model. About 30 New Zealand white rabbits underwent ACL replacement using a semitendinosus tendon autograft. The normal ACL was transected at its femoral and tibial insertions. The tendon graft was harvested without detachment of its tibial insertion and its free end was secured with sutures. The graft was then passed through one tibial and one femoral tunnel and secured at the lateral femoral condyle. All animals were divided into three groups and were killed at 3, 6 and 12 weeks after surgery. Nine more animals underwent ACL reconstruction using a free semitendinosus tendon autograft. These animals were used as controls. The intra-articular portion of the graft and the interface between the bone tunnel and the graft was evaluated postoperatively for gross morphology and histological appearance. Results of this study showed that in a rabbit model the semitendinosus tendon autograft retained its viability when harvested without detachment of its peripheral insertion. On contrary, at the control group, necrosis of the graft was observed 3 weeks after surgery and progressively revascularization and maturation occurred 6 and 12 weeks after surgery. Retaining the tibial insertion of the semitendinosus autograft seems to preserves its viability and bypasses the stages of avascular necrosis and revascularization that occurs with the use of a free tendon autograft.

Anterior cruciate ligament reconstruction with a porcine xenograft: a serologic, histologic, and biomechanical study in primates

PURPOSE

This study proposes treatment methods to provide a mechanically competent, immunocompatible, and sterile porcine graft for human knee ligament reconstruction.

METHODS

The anterior cruciate ligament (ACL) was reconstructed by using treated porcine patellar tendon grafts or controls of untreated porcine grafts or allografts in 20 rhesus monkeys. Animals were stratified into 2-, 6-, and 12-month postreconstruction cohorts. Serologic and histologic assessments were performed to evaluate host immunological and cellular response. Healing and functional integrity of the ACL reconstructions were assessed by tensile biomechanical testing.

RESULTS

Untreated porcine grafts were acutely resorbed and rejected, whereas treated porcine grafts and allografts were incorporated by the host as functional grafts. Temporal histologic assessment of treated porcine grafts and rhesus grafts revealed gradual host cellular infiltration and graft collagen remodeling through a similar mechanism of ligamentization. Biomechanical evaluations support graft functional integration with no difference between allograft and treated graft reconstructions.

CONCLUSION

Rhesus allograft and treated porcine grafts presented with similar healing profiles in a long-term evaluation of ACL reconstruction.

CLINICAL RELEVANCE

Immunochemical modification and sterilization of porcine patellar tendon grafts may improve initial biocompatibility and long-term functionality of xenografts in musculoskeletal applications.

Replacement of human anterior cruciate ligaments with pig ligaments: a model for anti-non-gal antibody response in long-term xenotransplantation

BACKGROUND

Understanding anti-non-gal antibody response is of significance for success in xenotransplantation. Long-term anti-non-gal response in humans was studied in patients transplanted with porcine patellar tendon (PT) lacking alpha-gal epitopes, for replacing ruptured anterior cruciate ligament (ACL).

METHODS

Porcine PTs were treated with recombinant alpha-galactosidase to eliminate alpha-gal epitopes and with glutaraldehyde for moderate cross-linking of collagen fibers. The processed pig PTs were implanted to replace ruptured ACL in patients.

RESULTS

In five of six evaluable subjects, the xenografts have continued to function for over two years and passed all functional stability assessments. Thus, processed porcine PT seems to be appropriate for replacing ruptured human ACL. Enzyme-linked immunosorbent assay and Western blot studies indicated that all subjects produced anti-non-gal antibodies against multiple pig xenoproteins, but not against human ligament proteins. Production of anti-non-gal antibodies peaked two to six months posttransplantation and disappeared after two years.

CONCLUSIONS

These antibodies contribute to a low-level inflammatory process that aids in gradual xenograft replacement by infiltrating host fibroblasts that align with the pig collagen "scaffold" and secrete collagen matrix. The assays monitoring anti-non-gal antibodies will help to determine whether long-term survival of live organ xenografts requires complete suppression of this antibody response.

Hamstring tendons regeneration after ACL reconstruction: an overview

Despite the long lasting research the ideal method of reconstructing the ACL has not been found so far. The last year's attention has shifted to the use of the multistrand hamstring tendon grafts. High ultimate tensile load, multiple-bundle replacement that better approximates the anatomy of the normal ACL and low donor site morbidity are the main advantages of this ACL replacement graft. These theoretical advantages have been multiplied when surprisingly studies have shown that semitendinosus and gracilis tendons actually regenerate after harvesting for use as ACL autografts. In this review article we summarize the current knowledge concerning the hamstring regeneration and we focus on issues that have clinical relevance or issues that have not been answered so far.

Anterior cruciate ligament reconstruction in females: a comparison of hamstring tendon and patellar tendon autografts

This study compared hamstring (HS) and patellar tendon (PT) anterior cruciate ligament (ACL) reconstruction in females. Sixty-five patients (43 HS, 22 PT) were evaluated at a mean 3.8-year postoperatively. Evaluation included IKDC 2000, SF-36, Cincinnati sports activity scores, anterior knee pain (AKP), kneeling pain, range of motion and anterior knee laxity. One PT patient sustained a traumatic graft rupture. There were no differences between the two grafts in terms of anterior knee laxity or IKDC scores. The HS group had higher sports activity scores and higher scores on the Physical Functioning and General Health subscales of the SF-36. Despite no difference in AKP, there was greater kneeling pain in the PT patients, who also had greater extension deficits. Both HS and PT are satisfactory ACL grafts in females, but HS grafts were associated with less morbidity, greater return to preinjury level of activity and higher quality of life scores.

ACL reconstruction: patellar tendon versus hamstring grafts--economical aspects

The aim of the present investigation was to compare the costs for the use of patellar tendon versus hamstring tendons as grafts for anterior cruciate ligament (ACL) reconstruction including the different fixation methods. The background is that during recent years there has been a dramatic shift from patellar tendon to hamstring tendons in ACL reconstructions in Sweden. All our patients with ACL reconstructions performed during 1 year (2004) were included. Knee joints numbering 440 in 439 patients were primary ACL reconstructions. A hamstring graft was used in 345 knee joints (78.4%) and a patellar tendon graft in 95 (21.6%) of the patients (Table 2). On average 34 (SD 12.9; range 14-63) ACL reconstructions per surgeon were performed by a total of 14 surgeons. The average cost for patellar tendon procedure was 197 euros compared to 436 euros for the hamstring procedure. Mean time for surgery in primary reconstructions was 11.5 min shorter (P<0.001) for patellar tendon reconstructions (71.3+/-31 min) compared to hamstring reconstructions (83.2+/-27 min). This means a difference in cost of 90 euros. The total additional cost (fixation and surgery time) for the hamstring method compared to the patellar tendon method was on an average 329 euros. From a strict economic point of view we therefore recommend or at least consider the use of the patellar tendon as a graft in ACL reconstructions.

Donor site morbidity and return to the preinjury activity level after anterior cruciate ligament reconstruction using ipsilateral and contralateral patellar tendon autograft: a retrospective, nonrandomized study

AIM

To compare the donor site morbidity after anterior cruciate ligament reconstruction using ipsilateral and contralateral bone-patellar tendon autograft.

STUDY DESIGN

Cohort study; Level of evidence, 2 PATIENTS AND METHOD: Between 1997 and 1999, 100 patients underwent anterior cruciate ligament reconstruction with autologous bone-patellar tendon graft. The reconstructions were performed using ipsilateral bone-patellar tendon graft in 52 patients (group Ip) and contralateral bone-patellar tendon graft in 48 patients (group Co). Group Co consisted of 2 subgroups: group CoD consisted of the donor knees (n=48) and group Co-ACL consisted of the anterior cruciate ligament-reconstructed knees (n=48). Mean follow-up was 39.2 months. Donor site morbidity was evaluated with a questionnaire, computerized historical data, KT-2000 arthrometer measurements, the Cincinnati score, and the Tegner score.

RESULTS

KT-2000 arthrometer evaluation showed a mean side-to-side difference of 0.6 mm in both groups. There were no significant differences between the 2 groups concerning the Cincinnati and Tegner scores. With regard to local tenderness, a significantly higher rate was found in group Ip (59.6%) and group Co-D (58.3%) compared with group Co-ACL (6.3%). In groups Ip and Co-D, high statistically significant differences were also found according to kneeling pain (69.2% and 70.8%, respectively) and knee-walking pain (76.9% and 70.8%, respectively) compared with group Co-ACL (6.3% and 10.4%, respectively). With regard to numbness, there was no statistical significance between the rates of all 3 groups: group Ip=75%, group Co-D=85.4%, and group Co-ACL=64.6%. There was one rupture of the patellar tendon and one patient with chronic patellar tendinitis, both in the donor knee of group Co-D.

CONCLUSION

The contralateral bone-patellar tendon graft appears to present no advantage over the ipsilateral graft, as all symptoms concerning donor site morbidity are shifted from the injured into the healthy knee, and return to activity is not more rapid.

Tendon regeneration: an anatomical and histological study in sheep

Utilization of the hamstring tendon in reconstruction of the anterior cruciate ligament (ACL) has become common in recent years. In MRI studies regeneration potential in harvested tendon has been observed. In the present study, 20 legs from ten sheep, which underwent 10 cm segment resection of tendon of musculus extensor digitalis lateralis (MEDL) were used. The sheep were killed 6 months after the operation and regenerated tendons were examined macroscopically and histologically. Dissection was performed in the tendon resection area and specimens were reharvested for histological examination. Regeneration of the tendon with normal anatomical topographies was found in all legs. Regeneration occurred on both sides of the resected tendon simultaneously. Regeneration was muscle-like in the proximal side but it was tendon-like in the distal side. The developed tendon was fused to the joint capsule and to the fascia at the joint line in all specimens. This study indicates that tendon has a potential for regeneration.

A randomized comparison of patellar tendon and hamstring tendon anterior cruciate ligament reconstruction

BACKGROUND

Patellar and hamstring tendon autografts are the most frequently used graft types for anterior cruciate ligament reconstruction, but few direct comparisons of outcomes have been published.

HYPOTHESIS

There is no difference in outcome between the two types of reconstruction.

STUDY DESIGN

Prospective randomized clinical trial.

METHODS

After isolated anterior cruciate ligament rupture, 65 patients were randomized to receive either a patellar tendon or a four-strand hamstring tendon graft reconstruction, and results were reviewed at 4, 8, 12, 24, and 36 months.

RESULTS

Pain on kneeling was more common and extension deficits were greater in the patellar tendon group. There were greater quadriceps peak torque deficits in the patellar tendon group at 4 and 8 months but not thereafter. In the hamstring tendon group, active flexion deficits were greater from 8 to 24 months, and KT-1000 arthrometer side-to-side differences in anterior knee laxity at 134 N were greater. Cincinnati knee scores, International Knee Documentation Committee ratings, and rates of return to preinjury activity levels were not significantly different between the two groups.

CONCLUSIONS

Both grafts resulted in satisfactory functional outcomes but with increased morbidity in the patellar tendon group and increased knee laxity and radiographic femoral tunnel widening in the hamstring tendon group.

Endoscopic anterior cruciate ligament reconstruction with patella tendon autograft

The patella tendon is the most commonly used graft source for ACL reconstruction because of its biomechanical strength and stiffness, the availability of bone-to-bone healing on either end, and the ability to firmly secure the graft within the tunnels. Consistently good results have been reported in the literature, with expectations to return to all activities at pre-injury levels of performance. We outline our technique for endoscopic ACL reconstruction using a patella tendon autograft. The technique is divided into the critical stages of pre-operative assessment, graft harvest, notch preparation, tunnel placement, graft passage, graft fixation, and rehabilitation. Methods for avoiding pitfalls and overcoming mishaps are described.

Alterations of the extensor apparatus after anterior cruciate ligament reconstruction using the medial third of the patellar tendon

PURPOSE

The objective of this study was the ultrasound evaluation of the donor defect of the patellar tendon (PT) and the radiologic evaluation of the patella after harvesting of the medial third as a bone-patella tendon-bone (BPTB) graft for anterior cruciate ligament (ACL) reconstruction.

TYPE OF STUDY

This was a cohort study.

METHODS

In 45 patients who had ACL reconstruction, the extensor apparatus of the donor side was studied using ultrasound cross-sections and radiographs (anteroposterior, lateral, and a tangential view of the patella) 3 to 70 months postoperatively. Patients were divided into two groups. The early postoperative group (3 to 30 months postoperative) consisted of 27 patients (group A) and the late postoperative group (31 to 70 months postoperative) consisted of 18 patients (group B). The healthy contralateral extensor apparatus was used as control.

RESULTS

In group A, the standard ultrasound cross-section area of the PT increased by 20.48%, whereas in group B, it decreased by 4.88%. In group A, the patellar height was decreased by 9.21% in the donor side compared with the control. In group B, the patellar height was decreased by 7.02%. In group A, the Merchant's congruence angle increased by 11.59 degrees, and for group B, this angle increased by 3.82 degrees. This finding indicated that, after the 30th postoperative month, lateral displacement of the patella was not statistically significant (P =.38). In addition, no significant differences were found in the lateral patellofemoral angle in either group.

CONCLUSIONS

Our study indicates that the tendon defect is always healed and the final tendon cross-section area is 95% of the contralateral after the 30th postoperative month. In addition, there was a nonsignificant slight lateral displacement of the patella. In contrast, other studies found shown that there is a slight medial displacement of the PT after using the central third as a BPTB graft.

Donor-site morbidity and anterior knee problems after anterior cruciate ligament reconstruction using autografts

The authors review the current knowledge on donor site-related problems after using different types of autografts for anterior cruciate ligament (ACL) reconstruction and make recommendations on minimizing late donor-site problems. Postoperative donor-site morbidity and anterior knee pain following ACL surgery may result in substantial impairment for patients. The selection of graft, surgical technique, and rehabilitation program can affect the severity of pain that patients experience. The loss or disturbance of anterior sensitivity caused by intraoperative injury to the infrapatellar nerve(s) in conjunction with patellar tendon harvest is correlated with donor-site discomfort and an inability to kneel and knee-walk. The patellar tendon at the donor site has significant clinical, radiographic, and histologic abnormalities 2 years after harvest of its central third. Donor-site discomfort correlates poorly with radiographic and histologic findings after the use of patellar tendon autografts. The use of hamstring tendon autografts appears to cause less postoperative donor-site morbidity and anterior knee problems than the use of patellar tendon autografts. There also appears to be a regrowth of the hamstring tendons within 2 years of the harvesting procedure. There is little known about the effect on the donor site of harvesting fascia lata and quadriceps tendon autografts. Efforts should be made to spare the infrapatellar nerve(s) during ACL reconstruction using patellar tendon autografts. Reharvesting the patellar tendon cannot be recommended due to significant clinical, radiographic, and histologic abnormalities 2 years after harvesting its central third. It is important to regain full range of motion and strength after the use of any type of autograft to avoid future anterior knee problems. If randomized controlled trials show that the long-term laxity measurements following ACL reconstruction using hamstring tendon autografts are equal to those of patellar tendon autografts, we recommend the use of hamstring tendon autografts because there are fewer donor-site problems.

Semitendinosus muscle in anterior cruciate ligament surgery: Morphology and function

PURPOSE

To evaluate the fate of the hamstring muscles in general and the semitendinosus muscle in particular, after anterior cruciate ligament (ACL) reconstruction with an autologous semitendinosus tendon graft from the ipsilateral side.

TYPE OF STUDY

Prospective consecutive case series investigation.

METHODS

Included were 16 consecutive patients, 14 male and 2 female, with a mean age of 26 years. The inclusion criterion was chronic unilateral ACL insufficiency with no concomitant knee ligament injuries. ACL reconstruction was performed with a quadruple semitendinosus tendon graft using the EndoButton technique (Acufex, Mansfield, MA). Intraoperatively, muscle specimens were taken from the semitendinosus muscle on the harvested side. Follow-up at a minimum of 6 months included clinical examination, isokinetic strength performance, magnetic resonance imaging (MRI) of the thigh and knee, and ultrasound-guided muscle biopsy procurement from the semitendinosus muscle for histochemical and enzymatic analyses.

RESULTS

Of the patients, 75% showed regeneration of their semitendinosus tendons. The neotendons all inserted below the knee joint where they had fused with the gracilis tendon to a conjoined tendon inserting in the pes anserinus. The semitendinosus muscle had a smaller cross-sectional area on the operated side but none showed total atrophy. Less atrophy was present in the patients with a regenerated semitendinosus neotendon compared with those without regeneration (P =.029). In the latter group the semimembranosus muscle seemed to compensate for this with hypertrophy (P =.019). Cross-sectional muscle fiber areas, the relative number of each fiber type and oxidative potential as estimated by citrate synthase activity, showed no significant differences between the operated and nonoperated legs. The isokinetic strength of the hamstrings and quadriceps was significantly lower in the operated leg than in the nonoperated leg.

CONCLUSIONS

With this surgical technique, the semitendinosus muscle can recover and the tendon has, according to the MRI images, a great potential to regenerate after its removal.

Effect of screw length on bioabsorbable interference screw fixation in a tibial bone tunnel

Initial tibial fixation strength is the weak link after anterior cruciate ligament reconstruction with a quadrupled hamstring tendon graft fixed with bioabsorbable interference screws. The purpose of this study was to determine the biomechanical differences between 28-mm and tapered 35-mm interference screws for tibial fixation of a soft tissue graft in 16 young cadaveric tibias. Failure mode, displacement before failure, and ultimate failure load were tested with a testing machine aligned with the tibial tunnel to simulate a worst-case scenario. The mode of failure was graft slippage past the screw in all but one of the specimens. The mean maximum load at failure of the 28-mm screw was 594.9 +/- 141.0 N, with mean displacement at failure of 10.97 +/- 2.20 mm. The mean maximum load at failure of the 35-mm screw was 824.9 +/- 124.3 N, with a mean displacement to failure of 14.38 +/- 2.15 mm. The 38% difference in mean maximal load at failure was significant. Important variables in hamstring tendon graft fixation within a bone tunnel include bone mineral density, dilatation, gap size, screw placement, and screw width and length. Attention to these variables will help to provide secure graft fixation during biologic incorporation throughout the rehabilitation period.

Patellar instability: assessment on MR images by measuring the lateral trochlear inclination-initial experience

Lateral trochlear inclination (LTI) of the knee was compared on magnetic resonance (MR) images obtained in 30 patients with patellar instability (PI) and 30 patients with nonspecific internal knee derangement. Differences in LTI values between the two populations were significant (P <.001). Reproducibility of the measurement was judged excellent with an intraclass correlation superior to 0.98. Below a threshold value fixed at 11 degrees, LTI appears to be an excellent diagnostic test of PI with a sensitivity of 0.93 (28/30), a specificity of 0.87 (26/30), and an accuracy of 0.90 (54/60).

Comparison of traditional and subcutaneous patellar tendon harvest. A prospective study of donor site-related problems after anterior cruciate ligament reconstruction using different graft harvesting techniques

Our goal was to compare the results after anterior cruciate ligament reconstruction using either the traditional one-incision or the subcutaneous two-incision technique to harvest the central third of the patellar tendon, particularly concerning disturbances in anterior knee sensitivity and the patient's ability to walk on his or her knees. One surgeon performed anterior cruciate ligament reconstruction on 124 patients with unilateral ruptures and no history of previous incisions in the anterior knee region. The traditional one-incision graft harvesting technique was used in 58 patients and the subcutaneous two-incision technique was used in 66 patients. At 2 years, the International Knee Documentation Committee classification, Lysholm score, arthrometry side-to-side difference, and single-legged hop test showed no significant differences between groups. The area of insensitivity was a median of 24 cm2 in the traditional harvest group and 0 cm2 in the subcutaneous harvest group. The patients with subcutaneous harvest had a tendency toward fewer problems during walking on their knees than did the patients with traditional harvest. Our conclusion is that the subcutaneous two-incision graft harvesting technique caused less disturbance in anterior knee sensitivity and a tendency of less discomfort during walking on one's knees than the traditional one-incision technique.

Revision anterior cruciate ligament surgery

An increasing number of revision ACL reconstructions are being performed each year. Revision ACL surgery is challenging and cannot be approached in the same manner as primary ACL surgery. Successful revision ACL surgery requires a detailed history, a comprehensive physical examination, appropriate radiologic studies, and careful preoperative planning. The results of revision ACL surgery do not equal the results of primary ACL surgery, and this should be explained to the patient prior to surgery. In order to avoid repeating errors that led to failure of the primary reconstruction, the etiology of the primary failure must be clearly understood before proceeding with the revision procedure. Although graft failure is the most common reason for failure of the original reconstruction and revision surgery, other non-graft-related problems, such as loss of motion, extensor mechanism dysfunction, and degenerative arthritis, can also result in an unsatisfactory outcome and residual complaints. Errors in surgical technique, specifically nonanatomic graft placement and failure to address associated ligamentous injuries at the time of the original procedure, are responsible for graft failures in most reported series. Preoperative planning must address the issues of graft selection, skin incisions, hardware removal, tunnel placement, graft fixation, and associated ligamentous injuries. Loss of motion and in some cases enlarged bone tunnels may require a staged approach. Because of the weaker initial graft fixation, laxity of secondary restraints, the potential need to address associated ligamentous injuries, and the presence of more significant articular cartilage changes, an accelerated rehabilitation program is inappropriate in most revision cases. Successful revision ACL surgery requires a motivated and compliant patient, a well thought out plan, and an experienced surgeon who is knowledgeable and proficient with a variety of different surgical techniques, graft sources, and graft fixation techniques.