Late patellar tendon ruptures after removal of the central third for anterior cruciate ligament reconstruction. A report of two cases

Patellar Tendon Rupture 12 Years after ACL Reconstruction with BPTB Autograft

We present a case of a 33-year-old male with a history of anterior cruciate ligament reconstruction (ACLR) with bone-patellar tendon-bone (BPTB) autograft and prior ipsilateral hamstring harvest, who presented with a complete patella tendon rupture (PTR) 12 years after ACLR. The patient underwent a successful patellar tendon (PT) repair augmented with Achilles tendon allograft and cerclage with nonabsorbable suture tape. PTR after ACLR with BPTB autograft is rare, particularly in patients over a decade out from the index procedure, but can occur. This case report highlights a novel technique for PT repair following BTB ACLR in a hamstring deficient knee.

Current trends in graft choice for primary anterior cruciate ligament reconstruction - part II: In-vivo kinematics, patient reported outcomes, re-rupture rates, strength recovery, return to sports and complications

Postoperative patient satisfaction after anterior cruciate ligament reconstruction (ACL-R) is influenced mainly by the degree of pain, the need for reoperation, and functional performance in daily activities and sports. Graft choice has shown to have an influence on postoperative outcomes after ACL-R. While patient reported outcomes measurements do not differ between graft options, evidence shows that normal knee kinematics is not fully restored after ACL-R with an increase in postoperative anterior tibial translation (ATT). Postoperative graft rupture rates seem to favor bone-patella-tendon-bone (BPTB) and quadriceps tendon (QT) autografts over HT or allografts. While return to sports rates seem comparable between different graft types, postoperative extensor strength is reduced in patients with BPTB and QT whereas flexion strength is weakened in patients with HT. Postoperative donor site morbidity is highest in BPTB but comparable between HT and QT. With all graft options having advantages and drawbacks, graft choice must be individualized and chosen in accordance with the patient.

Optimal Graft Choice in Athletic Patients with Anterior Cruciate Ligament Injuries: Review and Clinical Insights

Anterior cruciate ligament (ACL) rupture is a common sporting-related knee injury with a potentially detrimental impact on the athlete’s career, yet there is no formal consensus on the optimal graft choice for reconstructing the ruptured ACL in this specific population. Options for reconstruction include autograft, allograft, and artificial grafts. However, each has associated failure risk and donor site morbidity. Our operational definition of the athlete is a skeletally mature individual participating in high level activity with the expectation to return to pre-injury level of activity. The athlete has unique injury characteristics, post-operative expectations, and graft demands that differ to the general population. Long-term outcomes are of particular importance given on-going mechanical demands on the reconstructed knee. Therefore, the purpose of this review is to consolidate current literature on the various ACL reconstruction graft options, with a focus on the optimal graft for returning the athlete to activity with the lowest rate of re-injury.

Total Knee Arthroplasty after Anterior Cruciate Ligament Reconstruction

The incidence of anterior cruciate ligament (ACL) reconstruction is increasing in the United States, particularly in the older athlete. Patients who undergo ACL reconstruction are at higher risk for undergoing total knee arthroplasty (TKA) later in life. TKA in patients with prior ACL reconstruction has been associated with longer operative time due in-part to difficulty with exposure and retained hardware. Outcomes after TKA in patients with prior ACL reconstruction are not well defined, with some reports showing increased rate of complications and higher risk of reoperation compared with routine primary TKA, but these results are based on small and nonrandomized cohorts. Future research is needed to determine whether graft choice or fixation technique for ACL reconstruction influences outcomes after subsequent TKA. Furthermore, whether outcomes are affected by choice of TKA implant design for patients with prior ACL reconstruction warrants further study. This review analyzes the epidemiology, operative considerations, and outcomes of TKA following ACL reconstruction.

The patellar ligament: A comprehensive review

The patellar ligament (PL) is an epiphyseal ligament and is part of the extensor complex of the knee. The ligament has gained attention due to its clinical relevance to autograft and tendinopathy. A variety of anatomical variations of the PL such as aplasia, numerical variations, and vascularity are being reported recently by clinicians and anatomists. The aim of this literature was to review the available literature to provide a consensus regarding anatomic variations of the PL, neurovasculature surrounding the PL, histology of the PL, and various aspects of PL measurements with relevance to the surgical considerations and sex and age-related differences. A narrative review of the patellar ligament was performed by conducting a detailed literature search and review of relevant articles. A total of 90 articles on the patellar ligament were included and were categorized into studies based on anatomical variations, neurovasculature, morphometrics, microanatomy, sex and age-related difference, and ACL reconstruction. The anatomical variations and morphometrics of the PL were found to correlate with the frequency of strain injuries, tendinopathy, and efficacy of the PL autograft in anterior cruciate ligament reconstruction. The sex differences in PL measurements and the effect of estrogen on collagen synthesis explained a higher incidence of patellar tendinopathy in women. An awareness of its variations enables careful selection of surgical incisions, thereby avoiding complications related to nerve injury. Accurate knowledge of the PL microanatomy assists in understanding the mechanism of ligament degeneration, rupture, autograft harvesting, and ligamentization results.

Preoperative Estimated Width of the Patellar Tendon for Anterior Cruciate Ligament Reconstruction

This study aims to compare the actual patellar tendon width with the skin and magnetic resonance imaging (MRI) measurements and to describe a more accurate method to predict the actual patellar tendon width before anterior cruciate ligament reconstruction (ACLR).Thirty-nine patients undergoing primary ACLR were identified. Patients with patellar tendon width of less than 30 mm by skin or MRI measurements were excluded from the study. The actual patellar tendon width was measured as an intraoperative reading taken after surgical exposure. Mean difference between the skin and actual measurement and mean difference between the MRI and actual measurement was calculated. Paired t-test was run to determine any significant differences. A difference was also calculated between the actual measurement and the average sum of skin and MRI measurements for each patient. Skin thickness was compared to Δ (Δ = preincision skin measurement of patellar tendon width minus postincision actual measurement) by Spearman's correlation test. Mean difference between skin and actual measurements was 2.5 mm, with p = 0.001. Mean difference between MRI and actual measurement was -2.7 mm with p = 0.001. However, the mean difference between the actual and the average sum of skin and MRI measurements was 0.13 mm with p = 0.76. The Pearson's correlation coefficient, r _s, between average sum of skin and MRI measurements and the actual measurement was 0.6 with p = 0.001. There was no correlation found between the skin thickness and Δ∙. This study indicates that there is a significant difference between the actual patellar tendon width and the measurement of the tendon taken using a ruler on the skin or using MRI image software. However, the average sum of skin and MRI measurements, which is not significantly different from the actual width, can accurately predict the actual patellar tendon width before ACLR. The study reflects level IV evidence.

Open patellar tendon avulsion from tibial tuberosity after ACL reconstruction successfully treated with suture anchors

Patellar tendon rupture after anterior cruciate ligament (ACL) reconstruction is a rare complication which usually occurs in the early postoperative period during rehabilitation. The management of open avulsions from tibial tuberosity has not been clearly defined yet. We describe a previously unreported case of traumatic and open patellar tendon avulsion from tibial tuberosity one year following ACL reconstruction in an elite football player which was successfully treated with suture anchors. (www.actabiomedica.it)

In vivo evaluation of human patellar tendon microstructure and microcirculation with diffusion MRI

BACKGROUND

Patellar tendon (PT) microstructure integrity and microcirculation status play a crucial role in the progression of tendinopathy and tendon repair.

PURPOSE

To assess the feasibility and robustness of stimulated-echo based diffusion-weighted MRI with readout-segmented echo-planar imaging (ste-RS-EPI) for noninvasive assessment of microstructure and microcirculation of human PT.

STUDY TYPE

Prospective.

SUBJECTS

Fifteen healthy volunteers.

FIELD STRENGTH/SEQUENCE

PT diffusion tensor imaging (DTI) and intravoxel incoherent motion (IVIM) were acquired with an ste-RS-EPI protocol on a 3T MRI scanner.

ASSESSMENT

Subjects were positioned with their PT at the magic angle. DTI-derived parameters including axial diffusivity (AD), radial diffusivity (RD), mean diffusivity (MD), and fractional anisotropy (FA) were estimated with b-values of 0 and 800 s/mm² and 12 diffusion directions. IVIM-derived parameters, f _p , D* × f _p , V _b , and D* × V _b were assessed in the central-third and the outer-two thirds of the PT with b-values of 0, 20, 30, 60, 80, 120, 200, 400, and 600 s/mm² in three orthogonal directions.

STATISTICAL TESTS

Paired t-tests were used to evaluate differences in IVIM parameters between the central-third and outer-two thirds regions of the patellar tendon. Paired t-tests and within-subject coefficient of variation were used to assess the intra- and intersession reproducibility of PT DTI and IVIM parameters.

RESULTS

DTI parameters for healthy PT were 1.54 ± 0.09 × 10^-3 mm² /s, 1.01 ± 0.05 × 10^-3 mm² /s, 1.18 ± 0.06 × 10^-3 mm² /s, and 0.30 ± 0.04 for AD, RD, MD, and FA, respectively. Significantly higher (P < 0.05) IVIM parameters f _p and D* × f _p were observed in the outer-two thirds (6.1% ± 2.4% and 95.2 ± 49.6, respectively) compared with the central-third (3.8% ± 2.3% and 48.6 ± 35.2, respectively) of the PT.

DATA CONCLUSION

Diffusion MRI of PT with an ste-RS-EPI protocol is clinically feasible. Both DTI- and IVIM-derived parameters of the PT demonstrated good test-retest reproducibility and interrater reliability.

LEVEL OF EVIDENCE

2 Technical Efficacy: Stage 1 J. Magn. Reson. Imaging 2020;51:780-790.

Reliability and methodology of quantitative assessment of harvested and unharvested patellar tendons of ACL injured athletes using ultrasound tissue characterization

Background

Ultrasound tissue characterization (UTC) imaging has been previously used to describe the characteristics of patellar and Achilles tendons. UTC imaging compares and correlates successive ultrasonographic transverse tendon images to calculate the distribution of four color-coded echo-types that represent different tendon tissue types. However, UTC has not been used to describe the characteristics of patellar tendons after anterior cruciate ligament reconstruction (ACLR). The aim of this cross-sectional study was to assess the intra and inter-rater reliability of the UTC in unharvested and harvested patellar tendons of patients undergoing ACLR.

Methods

Intra and inter-rater reliability of both UTC data collection and analysis were assessed. Ten harvested and twenty unharvested patellar tendons from eighteen participants were scanned twice by the same examiner. Eleven harvested and ten unharvested patellar tendons from sixteen participants were scanned and analyzed twice by two different examiners. Twenty harvested and nineteen unharvested patellar tendons from twenty-three participants were analyzed twice by two examiners.

Results

Quantification of the proportion of echo-types I, II, III and IV in the areas of interest: (1) patella apex, (2) proximal tendon, (3) mid tendon, (4) distal tendon, and overall tendon of harvested and unharvested patellar tendons all displayed excellent intra-rater reliability (ICC_2,1: 0.94 to 0.99), excellent inter-rater reliability for harvested and unharvested patellar tendon scanning and analysis (ICC_2,1: 0.89 to 0.98), and excellent inter-rater reliability for analysis (ICC_2,1: 0.95 to 0.99). Intra-rater reliability for the measure of volume was good (ICC_2,1: 0.69 harvested, 0.67 unharvested), whilst mixed results were observed for the measure of mid tendon thickness (ICC_2,1: 0.88 harvested, 0.57 unharvested). Inter-rater reliability for scanning and analysis was good for volume (ICC_2,1: 0.67) and excellent for thickness (ICC_2,1: 0.97), while the inter-rater reliability for analysis was fair to poor for volume (ICC_2,1: 0.59 harvested, 0.30 unharvested), and excellent to poor for mid tendon thickness (ICC_2,1: 0.85 harvested, 0.24 unharvested).

Conclusion

UTC imaging is a reliable tool to characterize the quality of most aspects of unharvested and harvested patellar tendons in subjects undergoing ACLR.

Shear wave elastography of the healing human patellar tendon following ACL reconstruction

PURPOSE

Anterior cruciate ligament (ACL) ruptures are common and are frequently reconstructed using a patellar tendon (PT) autograft. Unfortunately, the time course of PT healing after ACL reconstruction is not particularly well understood. Thus, the primary objective of this study was to use shear wave elastography (SWE) to evaluate the extent to which shear wave speed (SWS) is associated with time after ACL reconstruction.

METHODS

Longitudinal SWE images were acquired from lateral, central, and medial regions of the PT from two groups: 30 patients who had undergone ACL reconstruction with a PT autograft within the preceding 40 months, and 30 age-matched asymptomatic control subjects. SWE images were acquired at 20° and 90° of passive flexion from both knees. In each subject group, statistical analyses assessed changes in mean SWS with time post-surgery, as well as differences in mean SWS between PT regions and limbs.

RESULTS

In the ACL reconstruction patients, mean SWS increased with time post-surgery in the lateral region of the involved knee (p = 0.025) and decreased with time post-surgery in the central region of the contralateral knee (p = 0.022).

CONCLUSION

The findings suggest that there is an association between the mechanical properties of the PT and time post-surgery in both the involved and contralateral limbs after ACL reconstruction. These changes are likely due to maturation of the donor site tissue and changes in gait/loading patterns following ACL rupture and reconstruction.

LEVEL OF EVIDENCE

Level II - Prospective Cohort.

Sonographic Measurement of the Patellar Tendon Should Predict Autograft Bone Patellar Tendon Bone (BPTB) Size: Comparison of Anatomical and Clinical Findings

The use of BPTB autograft is frequently used in ACL reconstruction, however, the risk of potential failure in patients with an anatomically unfavorable patellar tendon may predispose to reconstruction failure. Anatomical study of the extensor apparatus of the knee can provide knowledge about the best option obtain the graft and perform a better preoperative planning. Musculoskeletal ultrasound is a simple, reproducible, affordable technique that could be valid for patellar tendon evaluation. The objective of this study is to evaluate the reproducibility of the patellar tendon measurements by ultrasound and compare them with anatomical measurements, both in cadaver and patients undergoing ACLR. The study consists of two phases; first anatomical study in cadaver. The ultrasound measurement was performed by determining the length, width and thickness of the patellar tendon, both by ultrasound and anatomical dissection. The second phase is a cohort of 42 patients pending surgical ACLR. Previous ultrasound and intraoperative measurements were obtained. Regarding the anatomical study, statistical analysis did not show any differences comparing the measurements in length (p = ns) and thickness (p = ns) of the patellar tendon, although differences were obtained when comparing the results obtained for the width of the tendon after the ultrasound and anatomical measurement (p < 0.001). Same results were obtained in second phase of the study. The reproducibility of ultrasound measurements of the PT is comparable to intraoperatively measurements (without width measurement). These findings can be useful for preoperative planning in the reconstruction of ACL with BPTB Graft and to assess technical modifications prior to surgery.

Surgical Technique: Repair of Patella Tendon Rupture in a Previously Harvested Tendon for an Anterior Cruciate Ligament Reconstruction

Background:

A rare cause of patellar tendon (PT) ruptures is complications after bone-PT-bone (BPTB) graft harvest for anterior cruciate ligament (ACL) reconstruction. The atypical tear pattern in these patients can be technically challenging to address.

Description of Technique:

A Krackow suture fixation of the medial, tibial based PT was fixed with a knotless suture anchor to the patella. A Krackow suture fixation of the lateral, patella based PT was fixed with a knotless suture anchor to the tibia. Fiber Tape was used for an Internal Brace.

Patient and Methods:

We retrospectively reviewed a single patient with a proximal-medial and distal-lateral PT rupture following BPTB graft harvest for an ACL reconstruction. The described repair technique was used to repair the PT rupture. Follow-up was 6-months. Range of motion (ROM), functional outcome scores, and patient-reported outcomes were assessed and recorded.

Results:

Six-months postoperatively, the patient has regained full knee extension and flexion to 130 degrees. The patient has good quadriceps strength, and manual muscle testing shows no deficits in the operative leg. The patient is able to perform all of her activities of daily living and is discharged from physical therapy.

Conclusion:

We describe a novel technique that effectively repairs the atypical PT rupture pattern seen after ACL reconstruction using BPTB autograft. This technique allows for aggressive post-operative rehabilitation in ROM and strengthening.

Level of Evidence:

Level V.

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.

Outcome of Hamstring Autograft With Preserved Insertions Compared With Free Hamstring Autograft in Anterior Cruciate Ligament Surgery at 2-Year Follow-up

PURPOSE

To compare mechanical stability, functional outcome, and level of return to sports activity in patients undergoing anterior cruciate ligament (ACL) reconstruction with a free hamstring graft versus a graft with preserved insertions at 2-year follow-up.

METHODS

This study was a prospective, single-blind (the evaluator was blinded), randomized trial of 110 adult professional athletes who were randomly allocated into 2 groups. Group 1 consisted of 55 patients who underwent ACL reconstruction with hamstring tendon autograft with preserved insertions (technique 1), and group 2 consisted of 55 patients who underwent ACL reconstruction with free hamstring tendon autograft (technique 2). An anteromedial portal was used for drilling of the femoral tunnel in all cases. Patients were assessed for a minimum follow-up of 2 years with clinical tests, the Activities of Daily Living Function Scale and Sports Function Scale (Cincinnati knee score), knee arthrometer (KT-1000) testing, and the Tegner activity scale.

RESULTS

The average age of the patients was 27.0 ± 7.5 years in group 1 and 27.2 ± 5.7 years in group 2. At 24 months, the mean side-to-side difference by KT-1000 testing was 1.4 in group 1 and 2.2 in group 2 (P < .0001); the mean Cincinnati knee score (Activities of Daily Living Function Scale and Sports Function Scale) was 418.5 (median, 420; range, 400-420) and 406.8 (median, 420; range, 350-420), respectively (P < .0001); and the mean difference between the preinjury and postsurgery Tegner level of sports activity was 0.3 and 1.08, respectively (P = .027).

CONCLUSIONS

Although ACL reconstruction using hamstring autograft with preserved insertions resulted in statistically superior anterior stability, a better functional outcome, and a closer return to the preinjury level of sports activity as compared with free autograft, no clinically significant difference was proved.

LEVEL OF EVIDENCE

Level I, randomized controlled trial.

Increased Risk of Revision After Anterior Cruciate Ligament Reconstruction With Soft Tissue Allografts Compared With Autografts: Graft Processing and Time Make a Difference

BACKGROUND

The optimal graft for anterior cruciate ligament reconstruction (ACLR) remains controversial.

PURPOSE

To compare the risk of aseptic revision between bone-patellar tendon-bone (BPTB) autografts, hamstring autografts, and soft tissue allografts.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Prospectively collected ACLR cases reconstructed with BPTB autografts, hamstring autografts, and soft tissue allografts were identified using the Kaiser Permanente ACLR Registry. Aseptic revision was the endpoint. The type of graft and allograft processing method (nonprocessed, <1.8-Mrad irradiation with and without chemical processing [Allowash or AlloTrue], ≥1.8-Mrad irradiation with and without chemical processing, and chemical processing alone [BioCleanse]) were the exposures evaluated. Analyses were adjusted for age, sex, and race. Kaplan-Meier curves and Cox proportional hazards models were employed.

RESULTS

The cohort included 14,015 cases: there were 8924 (63.7%) male patients, there were 6397 (45.6%) white patients, 4557 (32.5%) ACLRs used BPTB autografts, 3751 ACLRs (26.8%) used soft tissue allografts, and 5707 (40.7%) ACLRs used hamstring autografts. The median age was 34.6 years for soft tissue allografts, 24.3 years for hamstring autografts, and 22.0 years for BPTB autografts. The crude nonadjusted revision rates were 85 (1.9%) in BPTB autograft cases, 132 (2.3%) in hamstring autograft cases, and 83 (2.2%) in soft tissue allograft cases. After adjusting for age, sex, and race, compared with hamstring autografts, a higher risk of revision was found with allografts with ≥1.8 Mrad without chemical processing after 2.5 years (hazard ratio [HR], 3.88; 95% CI, 1.48-10.12) and ≥1.8 Mrad with chemical processing after 1 year (HR, 3.43; 95% CI, 1.58-7.47) and with BioCleanse processed grafts at any time point (HR, 3.02; 95% CI, 1.40-6.50). Nonprocessed allografts and those irradiated with <1.8 Mrad with or without chemical processing were not found to have a different risk of revision compared with hamstring autografts. Compared with BPTB autografts, a higher risk of revision was seen with hamstring autografts (HR, 1.51; 95% CI, 1.15-1.99) and BioCleanse processed allografts (HR, 4.67; 95% CI, 2.15-10.16). Allografts irradiated with <1.8 Mrad with chemical processing (Allowash or AlloTrue) (HR, 2.19; 95% CI, 1.42-3.38) and without chemical processing (HR, 2.31; 95% CI, 1.40-3.82) had a higher risk of revision, as did allografts with ≥1.8 Mrad without chemical processing after 2 years (HR, 6.30; 95% CI, 3.18-12.48) and ≥1.8 Mrad with chemical processing (Allowash or AlloTrue) after 1 year (HR, 5.03; 95% CI, 2.30-11.00) compared with BPTB autografts. Nonprocessed allografts did not have a higher risk of revision compared with autografts. With the numbers available, direct comparisons between the specific allograft processing methods were not possible.

CONCLUSION

When soft tissue allografts are used for ACLR, processing and time from surgery affect the risk of revision. Tissue processing has a significant effect on the risk of revision surgery, which is most profound with more highly processed grafts and increases with increasing follow-up time. Surgeons and patients need to be aware of the increased risks of revision with the various soft tissue allografts used for ACLR.

Immediate post-operative pain in anterior cruciate ligament reconstruction surgery with bone patellar tendon bone graft versus hamstring graft

Background

Pain in the immediate post-operative period after anterior cruciate ligament (ACL) surgery, apart from an unpleasant experience for the patient, can act as a barrier for static quadriceps contractions and optimum execution of the initial rehabilitation protocol resulting in slow recovery and a later return to full function for a sportsperson. There is no report in the literature comparing pain in the immediate post-operative period after using the two most widely used autografts, bone patellar tendon bone (BPTB) graft and hamstring graft.

Methods

The present study compared the visual analogue scale (VAS) pain score in the immediate post-operative period after arthroscopic ACL reconstruction with the BPTB and hamstring autografts. Both groups consisted of 50 patients each. The mean age of the BPTB and hamstring cohorts was 26.9 ± 7.3 years (age range 18–59 years) and 26.7 ± 9.0 years (age range 17–52 years), respectively. Unpaired t test was applied to compare pain scores between the BPTB and hamstring cohorts.

Results

In the present study, patients in the BPTB cohort showed higher mean pain scores across all the post-operative time intervals except at 6 h. However, the difference in the mean VAS pain score at post-operative 6, 12,18, 24, 36 and 48 h in the two groups was statistically not significant (p value of 1, 0.665, 0.798, 0.377, 0.651 and 0.215 at 6, 12, 18, 24, 36 and 48 h, respectively).

Conclusions

Our study concludes that the arthroscopic ACL reconstruction with BPTB autograft and hamstring autograft is associated with similar pain in the immediate post-operative period. As a result, aggressive physiotherapy regime is not affected by the type of graft being used for ACL reconstruction, as the pain scores in the immediate post-operative period are similar for both techniques.

Trial registration

Clinical Trials Registry-India, CTRI/2016/01/006502

Revision Risk After Allograft Anterior Cruciate Ligament Reconstruction: Association With Graft Processing Techniques, Patient Characteristics, and Graft Type

BACKGROUND

Allograft tissue is a common graft choice for anterior cruciate ligament reconstruction (ACLR). Allograft sterilization methods vary widely across numerous commercial tissue vendors. Multiple studies, despite being limited in sample size, have suggested a higher rate of clinical failure associated with the use of allograft tissue in ACLR when compared with autograft.

PURPOSE

To examine the association of graft processing techniques, patient characteristics, and graft type with risk of revision surgery after allograft ACLR.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective cohort study was conducted that used an integrated United States health care system's ACLR registry to identify primary unilateral cases in which allografts were used. Aseptic revision was the endpoint of the study. Allograft type, processing methods (irradiation dose, AlloWash, AlloTrue, BioCleanse), and graft donor age were assessed as potential risk factors for revision, with adjustment for patient age, sex, and body mass index (BMI) by use of survival analysis. Hazard ratios (HR) and 95% confidence intervals (CIs) were calculated.

RESULTS

A total of 5968 primary ACLR cases with allograft were included in the study, of which 3688 (61.8%) were male patients. The median age of the cohort at the time of surgery was 34.1 years (interquartile range, 24.1-42.9 years). The mean time to follow-up (±SD) was 2.1 ± 1.5 years. There were 3751 (62.9%) allograft ACLRs using soft tissue, 1188 (19.9%) with Achilles tendon, and 1029 (17.2%) with bone-patellar tendon-bone (BPTB). Graft processing groups included BioCleanse (n = 367), AlloTrue or AlloWash (n = 2278), irradiation greater than 1.8 Mrad (n = 1146), irradiation up to 1.8 Mrad (n = 3637), and no irradiation (n = 1185). There were 156 (2.6%) aseptic revisions. After adjustment for patient age, sex, and BMI, the use of BioCleanse (HR = 2.45; 95% CI, 1.36-4.40) and irradiation greater than 1.8 Mrad (HR = 1.64; 95% CI, 1.08-2.49) were associated with a higher risk of revision when compared with all other methods of processing. BPTB allografts were at higher risk of revision (HR = 1.79; 95% CI, 1.20-2.66) when compared with soft tissue allografts. Conversely, with every 5-year increase in age, the risk of revision was 0.67 (95% CI, 0.61-0.73) times lower. Male patients were found to be at higher risk of revision when compared with females (HR = 1.47; 95% CI, 1.04-2.07). The use of AlloWash or AlloTrue processing, patient BMI, and graft donor age did not affect revision rate significantly.

CONCLUSION

In the largest known study of its kind examining outcome after primary allograft ACLR, graft irradiation greater than 1.8 Mrad, BioCleanse graft processing, younger patient age, male patients, and BPTB allograft were all associated with a higher risk of clinical failure and subsequent revision surgery.

A meta-analysis of bone-patellar tendon-bone autograft versus four-strand hamstring tendon autograft for anterior cruciate ligament reconstruction

BACKGROUND

There is a lack of comprehensive studies comparing the clinical outcome of anterior cruciate ligament (ACL) reconstruction with either a bone-patellar tendon-bone (BPTB) or four-strand hamstring tendon (4SHT) autografts. The optimal choice of graft for anterior cruciate ligament reconstruction remains controversial.

PURPOSE

The objective of this study was to evaluate the effectiveness of BPTB autografts versus 4SHT autografts for the reconstruction of ACL.

METHODS

A systematical search of literature was performed in Pubmed, Embase, and the Cochrane library to identify published clinical prospective studies relevant to ACL reconstruction comparing BPTB and 4SHT autografts. The results of the eligible studies were analysed in terms of instrumented laxity measurements, Lachman test, pivot shift test, objective International Knee Documentation Committee (IKDC) scores, return to preinjury activity level, and morbidity of graft failure, anterior knee pain, kneeling pain, extension deficit, and flexion deficit. Study quality was assessed by using the Jadad scale for randomized clinical trial (RCT) and the Newcastle-Ottawa Scale (NOS) for prospective cohort study (PCS). Two reviewers independently assessed each study for quality and extracted data. Subgroup analysis of the primary outcomes was conducted according to the type of study design (RCT or PCS).

RESULTS

Twenty-two studies, with 931 patients in the BPTB group and 999 patients in the 4SHT group, met the inclusion criteria. Fourteen studies were randomized controlled trials, and eight were prospective cohort studies. The results of the meta-analysis showed that there were no significant differences between BPTB and 4SHT in terms of instrumented laxity measurements (P=0.06), Lachman test (P=0.58), objective IKDC scores (P=0.31), graft failure (P=0.45), extension deficit (P=0.06) and flexion deficit (P=0.63). However, outcomes in favour of BPTB were found in terms of pivot shift test (P=0.01) and return to preinjury activity level (P=0.03); outcome measures that favours 4SHT included anterior knee pain (P<0.01) and kneeling pain (P<0.01). These findings were still robust during the sensitivity analysis. Results from subgroup analysis of the primary outcomes were consistent with the overall analysis.

CONCLUSION

Based on the results above, ACL reconstruction with BPTB autografts might be superior in resuming rotation stability of the knee joint and allow patients to return to higher levels of activity in comparison with 4SHT autografts. Whereas, postoperative complications of the knee joint were lower for 4SHT autografts than for BPTB autografts. There was insufficient evidence to identify which of the two types of grafts was significantly better for ACL reconstruction considering the limitations of this study. More high-quality randomized controlled trials with strictly specified inclusion criteria are highly required before drawing a reliable conclusion.

Comparison of allograft versus autograft anterior cruciate ligament reconstruction graft survival in an active adolescent cohort

BACKGROUND

Graft selection for anterior cruciate ligament (ACL) reconstructive surgery is a controversial topic. Few studies have compared graft outcomes in adolescents.

PURPOSE

To identify factors related to ACL graft failure in an adolescent cohort.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

After institutional review board approval was obtained, adolescent subjects (age range, 11-18 years) who underwent primary ACL reconstruction surgery at a large tertiary pediatric hospital between July 2005 and July 2009 were identified through a query of International Classification of Diseases, 9th Revision, diagnostic and Current Procedural Terminology codes. Subject data were obtained by means of a retrospective chart review, phone survey, and the administration of functional knee outcome instruments. A multivariate Cox proportional hazards regression analysis was used to analyze factors related to graft survival.

RESULTS

The average ages at surgery in the allograft (n = 38) and autograft (n = 35) groups were 15.29 ± 2.24 and 15.60 ± 1.57 years, respectively. There were 11 graft failures (28.95%) in the allograft group compared with 4 graft failures (11.43%) in the autograft group. In the multivariate model, graft type (P = .0352) and postoperative knee laxity according to the Lachman test (P = .0217) were the only variables significantly related to graft survival. The hazard of graft failure was 4.4 (95% CI, 1.23-18.89) times greater in the allograft group compared with the autograft group. The hazard of graft failure was 5.28 times (95% CI, 1.1-12.72; P = .0217) greater for a subject who demonstrated increased postoperative knee laxity relative to the contralateral knee. The risk for autograft failure tended to remain constant 24 to 48 months after initial surgery, whereas the risk for allograft failure continued to increase during postoperative months 24 to 48. There were no differences (P > .05) between the allograft and autograft groups with respect to International Knee Documentation Committee score, Lysholm score, and the rate of return to previous activity level.

CONCLUSION

Graft type and postoperative knee laxity were identified as significant predictors of graft survival. On the basis of this large retrospective cohort, we recommend the use of autogenous grafts in children and adolescents undergoing primary, transphyseal ACL reconstruction. Patients who demonstrate increased translation during a postoperative Lachman test should be carefully followed because of concerns for subsequent graft failure.

Semitendinosus muscle fatty infiltration following tendon harvest in rabbits

The hamstring tendon autograft is one of the most commonly used graft choices in Anterior cruciate ligament (ACL) reconstruction. There are conflicting results regarding postoperative hamstring strength deficits in patients who have had a hamstring graft. The semitendinosus tendon has been shown to regenerate after harvesting for ACL autograft, suggesting that the muscle has the potential to regain normal function. However, no studies have been performed to define the microstructural changes that occur in the semitendinosus muscle after tendon resection. In this study, we hypothesized that fatty infiltration of the semitendinosus muscle after tendon harvest in New Zealand White rabbits increases postoperatively and remains constant or increases during the first year of repair. The semitendinosus tendon was unilaterally detached and harvested from 15 rabbits. Five rabbits were sacrificed at 3-, 6-, and 12-month intervals, and the semitendinosus muscle-tendon units were analyzed. The contralateral unoperated limb served as the control. The gross tendon and muscle dimensions and histologic percentage of fatty infiltration were measured. We found no significant difference in fatty infiltration at any time point between the control muscle and test specimens and that there was no progression of fatty infiltration over time. If these results hold true in humans, natural repair of the hamstring muscle following tendon harvest during ACL autograft reconstruction is not inhibited by fatty infiltration.

Optimization of culture conditions for stem cells derived from human anterior cruciate ligament and bone marrow

Tissue engineering with stem cells is a fascinating approach for treating anterior cruciate ligament (ACL) injuries. In our previous study, stem cells isolated from the human anterior cruciate ligament were shown to possess extensive proliferation and differentiation capabilities when treated with specific growth factors. However, optimal culture conditions and the usefulness of fetal bovine serum (FBS) as a growth factor in in vitro culture systems are yet to be determined. In this study, we compared the effects of different culture media containing combinations of various concentrations of FBS and the growth factors basic fibroblastic growth factor (bFGF) and transforming growth factor-β1 (TGF-β1) on the proliferation and differentiation of ligament-derived stem cells (LSCs) and bone marrow mesenchymal stem cells (BMSCs). We found that α-MEM plus 10% FBS and bFGF was able to maintain both LSCs and BMSCs in a relatively undifferentiated state but with lower major extracellular matrix (ECM) component gene expression and protein production, which is beneficial for stem cell expansion. However, the differentiation and proliferation potentials of LSCs and BMSCs were increased when cultured in MesenPRO, a commercially available stem cell medium containing 2% FBS. MesenPRO in conjunction with TGF-β1 had the greatest ability to induce the differentiation of BMSCs and LSCs to ligament fibroblasts, which was evidenced by the highest ligamentous ECM gene expression and protein production. These results indicate that culture media and growth factors play a very important role in the success of tissue engineering. With α-MEM plus 10% FBS and bFGF, rapid proliferation of stem cells can be achieved. In this study, MesenPRO was able to promote differentiation of both LSCs and BMSCs to ligament fibroblasts. Differentiation was further increased by TGF-β1. With increasing understanding of the effects of different culture media and growth factors, manipulation of stem cells in the desired direction for ligament tissue engineering can be achieved.

Tear patterns, surgical repair, and clinical outcomes of patellar tendon ruptures after anterior cruciate ligament reconstruction with a bone-patellar tendon-bone autograft

BACKGROUND

Patellar tendon ruptures are rare after graft harvest for anterior cruciate ligament (ACL) reconstruction. Few reports are available in the literature.

PURPOSE

To report the common tear patterns and results of treatment with tendon repair and cable augmentation.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

All tendon ruptures were repaired to bone with suture anchors and augmented with a Dall-Miles cable, followed by an aggressive rehabilitation protocol. The tear location was recorded. Range of motion, strength, and subjective survey testing were conducted preoperatively and postoperatively.

RESULTS

Thirteen patellar tendon ruptures were found from our database of 5364 ACL reconstructions, for an incidence of 0.24%. Seven ruptures occurred from the patellar origin medially and the tibial attachment laterally in a Z-shaped pattern. Four were completely distal, and 2 were completely proximal ruptures. All patients exhibited early flexion loss, but 11 of 13 patients maintained full, terminal hyperextension throughout treatment. The mean postoperative side-to-side flexion deficit was 33° at 1 month, 6° at 3 months, and 3° at latest follow-up at a mean of 4.8 years after tendon repair (range, 1-16 years). By International Knee Documentation Committee (IKDC) criteria, 10 patients had normal flexion, and 3 were nearly normal at latest follow-up. Twelve patients had normal extension, and 1 had nearly normal extension at latest follow-up. Mean isokinetic quadriceps muscle strength was 68.7% of the other side at 3 months after repair and 100.0% at latest follow-up, occurring at a mean of 47.5 months (range, 12-120 months). At a mean of 2 years (range, 1-4 years) after repair, the mean modified Noyes subjective score was 89.8 ± 9.2.

CONCLUSION

Patellar tendon ruptures are rare after ACL graft harvest. These ruptures usually occur in either a proximal-medial and distal-lateral pattern or an entirely distal pattern, in contrast to the proximal-only tear pattern commonly observed in unharvested patellar tendons. Good objective and subjective results were achieved with repair of postoperative patellar tendon ruptures using suture anchors and Dall-Miles cable augmentation, followed by aggressive, immediate range of motion exercises.

Tendon-derived stem cells (TDSCs) promote tendon repair in a rat patellar tendon window defect model

Injured tendons heal slowly and often result in the formation of mechanically and functionally inferior fibrotic scar tissue or fibrous adhesions. This study investigated the use of tendon-derived stem cells (TDSCs) for tendon repair in a rat patellar tendon window defect model. Fibrin glue constructs with or without GFP-TDSCs were transplanted into the window defect. The patellar tendons were harvested for histology, ex vivo fluorescent imaging and biomechanical test at various time points up to week 4. Our results showed that TDSCs significantly enhanced tendon healing as indicated by the increase in collagen production as shown by hematolxylin stain-ability of the tissue, improvement of cell alignment, collagen fiber alignment and collagen birefringence typical of tendon. The labeled cells were observed at weeks 1 and 2 and became almost undetectable at week 4. Both the ultimate stress and Young's modulus were significantly higher in the TDSCs group compared to those in the fibrin glue group at week 4. In conclusion, TDSCs promoted earlier and better repair in a rat patellar tendon window defect model.

Patients' attitudes and factors in their selection of grafts for anterior cruciate ligament reconstruction

Surgeon recommendation is the primary influence for patients choosing a graft for their ACL reconstruction. However, it is unknown if demographic factors also play a role. We hypothesize that education, age, and living in an urban setting may influence a patient's graft choice. Patients who had an ACL reconstruction from 2005 to 2009 were identified retrospectively, and received a written survey on their demographics and the factors affecting graft choice. They also rated their perception of those factors based on a Likert scale. Out of 471 surveys distributed, 151 responses were received. The mean follow-up time was 19 months (range, 1 to 63 months). Autograft was used in 57%. Surgeon recommendation was the primary factor in graft choice (63%). 87.4% of patients felt they made the right choice; only 4.6% would have picked a different graft if they could choose over again. More than half (51.7%) of patients did significant personal research, and used mostly medical websites (41.1%). 67.6% of patients were not adverse to allograft. The primary factor for patients in graft choice was surgeon recommendation. Still, the use of medical websites was widespread, and patients in an urban environment were less likely to rely solely on their surgeon's recommendation. Older patients were more concerned with autograft donor site morbidity, and patients with a higher level of education were less averse to allograft.

Allografts in Anterior Cruciate Ligament Reconstruction

Usual allograft sources for anterior cruciate ligament (ACL) reconstruction are patellar ligament, Achilles tendon, tibialis anterior, and posterior. The advantages of the use of allograft include reduced donor-site morbidity, shorter operative time, smaller incisions, and no size restrictions. The disadvantages include increased cost, slower graft embodiment, and the risk of viral or bacterial infection, which may occur either by transmission from an infected donor or by contamination by the healthcare provider. Careful donor selection, aseptic graft procurement and processing, and tissue sterilization, by irradiation or proprietary chemical processing, are the three major steps of the graft preparation procedure. Successful allograft implantation depends on sterility, reduction of antigenicity, and preservation of the biomechanical properties of the graft. To date, reports on the clinical and functional outcomes of allograft compared to autograft ACL reconstruction are controversial. Overall, graft choice depends on surgeon and patient preference, since no graft can perfectly match the properties of the native ACL.

Surgery for anterior cruciate ligament deficiency: a historical perspective

The anterior cruciate ligament (ACL) has entertained scientific minds since the Weber brothers provided biomechanical insight into the importance of the ACL in maintaining normal knee kinematics. Robert Adams described the first clinical case of ACL rupture in 1837 some 175 years to date, followed by Mayo-Robson of Leeds who performed the first ACL repair in 1895. At that time, most patients presented late and clinicians started to appreciate signs and symptoms and disabilities associated with such injuries. Hey Groves of Bristol provided the initial description of an ACL reconstruction with autologous tissue graft in 1917, almost as we know it today. His knowledge and achievements were, however, not uniformly appreciated during his life time. What followed was a period of startling ingenuity which created an amazing variety of different surgical procedures often based more on surgical fashion and the absence of a satisfactory alternative than any indication that continued refinements were leading to improved results. It is hence not surprising that real inventors were forgotten, good ideas discarded and untried surgical methods adopted with uncritical enthusiasm only to be set aside without further explanation. Over the past 100 years, surgeons have experimented with a variety of different graft sources including xenograft, and allografts, whilst autologous tissue has remained the most popular choice. Synthetic graft materials enjoyed temporary popularity in the 1980 and 1990s, in the misguided belief that artificial ligaments may be more durable and better equipped to withstand stresses and strains. Until the 1970s, ACL reconstructions were considered formidable procedures, often so complex and fraught with peril that they remained reserved for a chosen few, never gaining the level of popularity they are enjoying today. The increasing familiarity with arthroscopy, popularised through Jackson and Dandy, and enhancements in surgical technology firmly established ACL reconstruction as a common procedure within the realm of most surgeons' ability. More recently, the principle of anatomic ACL reconstruction, aiming at the functional restoration of native ACL dimensions and insertion sites, has been introduced, superseding the somewhat ill-advised concept of isometric graft placement. Double-bundle reconstruction is gaining in popularity, and combined extra- and intra-articular procedures are seeing a revival, but more accurate and reliable pre- and post-operative assessment tools are required to provide customised treatment options and appropriate evaluation and comparability of long-term results. Modern ACL surgery is united in the common goal of re-establishing joint homoeostasis with normal knee kinematics and function which may ultimately assist in reducing the prevalence of post-operative joint degeneration. This review hopes to provide an insight into the historical developments of ACL surgery and the various controversies surrounding its progress. Level of evidence V.

Quality of life and clinical outcome comparison of semitendinosus and gracilis tendon versus patellar tendon autografts for anterior cruciate ligament reconstruction: an 11-year follow-up of a randomized controlled trial

BACKGROUND

There are still controversies about graft selection for primary anterior cruciate ligament reconstruction. Prospective, randomized long-term studies are needed to determine the differences between the graft materials.

HYPOTHESIS

Eleven years after anterior cruciate ligament reconstruction there is no difference in functional outcome and quality of life between patients with patellar tendon or hamstring tendon autografts; however, the patients with patellar tendon autograft would have a higher prevalence of osteoarthritis.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

From June 1999 to March 2000, 64 patients were included in this prospective study. A single surgeon performed primary arthroscopically assisted anterior cruciate ligament reconstruction in an alternating sequence. In 32 patients, anterior cruciate ligament reconstruction was performed with hamstring tendon autograft (semitendinosus and gracilis [STG] group) while in the other 32 patients the reconstruction was performed with patellar tendon autograft (PT group).

RESULTS

At the 11-year follow-up, no statistically significant differences were seen with respect to the Lysholm score and Short Form-36, KT-1000 arthrometer laxity testing, anterior knee pain, single-legged hop test, or International Knee Documentation Committee (IKDC) classification results. Positive pivot-shift test (1+) was significantly more frequent in the PT group (P = .036). Twenty-two patients (81%) in the STG group and 18 patients (72%) in the PT group were still at their preinjury level of activity. Graft rupture occurred in 2 patients from the STG group (6%) and in 4 patients from the PT (12%). Grade B and C abnormal radiographic findings were seen in 84% (21 of 25) of patients in the PT group and in 63% (17 of 27) of patients in the STG group (P = .008).

CONCLUSION

Both hamstring and patellar tendon autografts provided good subjective outcomes and objective stability at 11 years. Positive pivot-shift test (1+) was significantly more frequent in the PT group. No significant differences in the rate of graft failure were identified. Patients with patellar tendon graft had a greater prevalence of osteoarthritis at 11 years after surgery.

The influence of graft choice on isokinetic muscle strength 4-24 months after anterior cruciate ligament reconstruction

PURPOSE

Regaining adequate strength of the quadriceps and hamstrings after anterior cruciate ligament (ACL) reconstruction is important for maximizing functional performance. However, the outcome of muscle strength after either BPTB or hamstrings autograft is unclear given the plethora of published studies that report post-operative muscle strength. The purpose of this study was to systematically compare the muscle strength of patients who have undergone ACL reconstruction using either Bone Patellar Tendon Bone (BPTB) or Hamstrings (HST) autograft.

METHODS

The databases of MEDLINE, Cinahal and EMBASE were systematically searched for articles that report muscle strength outcome following ACL reconstruction. The quality of the studies was evaluated and a meta-analysis of the muscle strength outcomes was conducted on reported data.

RESULTS

Fourteen studies were included in this systematic review: eight Randomized Control Studies (RCT) and six non-Randomized Control Studies (non-RCT). A meta-analysis was performed involving eight of the included studies (4 RCTs & 3 non-RCTs). At 60°/s and 180°/s, patients with BPTB graft showed a greater deficit in extensor muscle strength and lower deficit in flexor muscle strength compared with patients with HST.

CONCLUSION

This systematic review of Level III evidence showed that isokinetic muscle strength deficits following ACL reconstruction are associated with the location of the donor site. These deficits appear to be unresolved up to 2 years after ACL reconstruction.

LEVEL OF EVIDENCE

III.

Comparison of potentials between stem cells isolated from human anterior cruciate ligament and bone marrow for ligament tissue engineering

We have previously isolated and identified stem cells from human anterior cruciate ligament (ACL). The purpose of this study was to evaluate the differences in proliferation, differentiation, and extracellular matrix (ECM) formation abilities between bone marrow stem cells (BMSCs) and ACL-derived stem cells (LSCs) from the same donors when cultured with different growth factors, including basic fibroblast growth factor (bFGF), epidermal growth factor, and transforming growth factor-beta 1 (TGF-beta1). Ligament tissues and bone marrow aspirate were obtained from patients undergoing total knee arthroplasty and ACL reconstruction surgeries. Proliferation, colony formation, and population doubling capacity as well as multilineage differentiation potentials of LSCs and BMSCs were compared. Gene expression and ECM production for ligament engineering were also evaluated. It was found that BMSCs possessed better osteogenic differentiation potential than LSCs, while similar adipogenic and chondrogenic differentiation abilities were observed. Proliferation rates of both LSCs and BMSCs were enhanced by bFGF and TGF-beta1. TGF-beta1 treatment significantly increased the expression of type I collagen, type III collagen, fibronectin, and alpha-smooth muscle actin in LSCs, but TGF-beta1 only upregulated type I collagen and tenascin-c in BMSCs. Protein quantification further confirmed the results of differential gene expression and suggested that LSCs and BMSCs increase ECM production upon TGF-beta1 treatment. In summary, in comparison with BMSCs, LSCs proliferate faster and maintain an undifferentiated state with bFGF treatment, whereas under TGF-beta1 treatment, LSCs upregulate major tendinous gene expression and produce a robust amount of ligament ECM protein, making LSCs a potential cell source in future applications of ACL tissue engineering.

Patellar tendon anterior cruciate ligament reconstruction in the high-demand patient: evaluation of autograft versus allograft reconstruction

PURPOSE

This study sought to compare patient-reported and objective outcomes in high-demand patients after anterior cruciate ligament reconstruction with either patellar tendon allograft or autograft by use of a matched-pairs case-control experimental design.

METHODS

Nineteen matched pairs were obtained based on gender (36.8% female patients), age (27.9 +/- 8.1 years in autograft group v 28.1 +/- 9.1 years in allograft group), and length of follow-up (9.1 +/- 2.7 years in autograft group v 10.3 +/- 2.6 years in allograft group). All patients reported participating in very strenuous (soccer, basketball, and so on) or strenuous (skiing, tennis, and so on) sporting activity 4 to 7 times per week before their knee injury. Patient-reported outcomes included the International Knee Documentation Committee Subjective Knee Form, Activities of Daily Living and Sports Activity Scales of the Knee Outcome Survey, and Short Form 36. Clinical evaluation included knee range of motion, laxity, and functional strength.

RESULTS

There were no statistically significant differences in gender, age, or body mass index. There was a slight difference in length of follow-up (P < .05). The groups showed no statistically significant differences in any of the patient-reported or objective outcome measures. More autograft patients reported that they were able to perform very strenuous activity without the sense of instability (14 v 7), but this difference only approached statistical significance (P < .07). Twelve autograft patients were able to return to preinjury levels of sporting activity compared with ten allograft patients. Sixteen autograft patients and twelve allograft patients were able to participate in strenuous or very strenuous sporting activity at follow-up. Both differences were not statistically significant.

CONCLUSIONS

Autograft and fresh-frozen allograft patellar tendon anterior cruciate ligament reconstruction exhibit similar patient-reported and objective outcomes in high-demand individuals at 3 to 14 years' follow-up.

LEVEL OF EVIDENCE

Level III, therapeutic case-control study.

Osteointegration of soft tissue grafts within the bone tunnels in anterior cruciate ligament reconstruction can be enhanced

Anterior cruciate ligament reconstruction with a soft tissue autograft (hamstring autograft) has grown in popularity in the last 10 years. However, the issues of a relatively long healing time and an inferior histological healing result in terms of Sharpey-like fibers connection in soft tissue grafts are still unsolved. To obtain a promising outcome in the long run, prompt osteointegration of the tendon graft within the bone tunnel is essential. In recent decades, numerous methods have been reported to enhance osteointegration of soft tissue graft in the bone tunnel. In this article, we review the current literature in this research area, mainly focusing on strategies applied to the local bone tunnel environment. Biological strategies such as stem cell and gene transfer technology, as well as the local application of specific growth factors have been reported to yield exciting results. The use of biological bone substitute and physical stimulation also obtained promising results. Artificially engineered tissue has promise as a solution to the problem of donor site morbidity. Despite these encouraging results, the current available evidence is still experimental. Further clinical studies in terms of randomized control trial in the future should be conducted to extrapolate these basic science study findings into clinical practice.

MECHANICAL RESISTANCE OF THE PATELLAR LIGAMENT AFTER REMOVAL OF THE MIDDLE THIRD THROUGH EITHER ONE LONGITUDINAL INCISION OR TWO MINI-TRANSVERSE INCISIONS

OBJECTIVE

To evaluate the resistance and regeneration of the patellar ligament after harvesting a graft for reconstruction of the anterior cruciate ligament, using the traditional technique of a single longitudinal skin incision or a technique of two transverse mini-incisions, in sheep.

METHODS

Ten sheep were used. In the right knee, we removed the graft using the traditional method, and in the left knee, using the two-incision method. The animals were observed for six months. The specimens (patellar ligament, tibia and patella) were adapted to the mechanical test machine for ligament resistance tests.

RESULTS

No difference was found between the two proposed techniques in relation to the regeneration and resistance of the patellar ligament. However, we observed that shortening of the patellar ligament occurred in both groups, and that suturing of the superficial fascia of the patellar ligament did not influence the regeneration of the patellar ligament, according to the histology.

CONCLUSION

The technique using two incisions in the skin presents the same patterns of regeneration and resistance of the remaining patellar ligament as shown by the traditional technique of a single, longitudinal incision.

Factors affecting patient selection of graft type in anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to assess factors associated with patient selection of graft type for anterior cruciate ligament (ACL) reconstruction.

METHODS

We retrospectively identified 1,038 patients who underwent ACL reconstruction over a 5-year period. Surgery was performed by 5 different surgeons. A questionnaire was sent to patients at a minimum of 24 months' follow-up to determine which type of graft was used, why they chose that graft, whether they were satisfied with their graft and outcome, and whether they would choose another graft and, if so, which one; it also included a visual analog scale to rate their recovery.

RESULTS

Questionnaires were received from 240 patients. The mean follow-up from the time of surgery was 41.3 months (range, 24 to 96 months). There were a variety of allografts and autografts used. Overall, allograft was used in 63.3% of patients and autograft in 35.4%. The most common factor influencing graft selection was physician recommendation (74.2%). Patients rated their recovery on average as 8.48 (+/-1.8) out of 10 on the visual analog scale (range, 0 to 10). Of the patients, 93% were satisfied with their graft selection. Only 12.7% would choose another graft if in the situation again. Of these patients, 63.3% would change from an autograft to allograft.

CONCLUSIONS

This study suggests that the most important factor for a patient choosing a graft for ACL reconstruction is physician recommendation. Our study has shown an increasing trend in our group toward the use of allograft materials for ACL reconstruction (63.3% of all graft materials selected). Of the individuals who were dissatisfied with their graft, 63% who originally chose autograft would choose allograft as a source in the future.

LEVEL OF EVIDENCE

Level III, prognostic case-control study.

What do we really know about allografts?

The use of allografts in sports medicine is becoming increasingly popular, and, therefore, this issue of Clinics in Sports Medicine is dedicated to the use of allografts in sports medicine. The majority of indications are related to the use of soft tissue grafts for ligament reconstruction, osteochondral (OC) allografts for articular surface reconstruction, and meniscal allografts for meniscal transplantation. There is an increasing amount of science and literature dealing with healing and outcomes, but many questions still remain. There are a number of issues, controversies, and lack of long-term outcomes to make definitive statements on what is really known about allograft use in sports medicine.

[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.

Effects of stress shielding and subsequent restressing on mechanical properties of regenerated and residual tissues in rabbit patellar tendon after resection of its central one-third

Central third of patellar tendon (PT) is used as an autograft for anterior cruciate ligament (ACL) reconstruction. Previous studies investigated temporal changes in material properties of healing tissues in PT after resection of the central third. However, no study has been performed on effects of stress shielding (SS) and restressing (RS) on the properties of healing tissues. The present study hypothesised that SS adversely affects the mechanical integrity of healing tissues, which is recovered by subsequent RS. An entire rectangular defect was created in the central third of rabbit PT. Operated PTs were subjected to either SS or no stress shielding (NSS). A subgroup of stress-shielded PTs was followed by the resumption of normal loading, namely RS. Tensile properties of tissues regenerated in the defect and residual tendons were evaluated. Regenerated tissues of SS for 3 weeks resulted in significantly lower strength than NSS, which was recovered to NSS level by 3 weeks of RS. Strength of residual tissues in RS reversed SS effects, leading to the strength at NSS level after 12 weeks. However, tangent modulus of residual tissues in RS was still significantly lower than that of NSS at 12 weeks. Therefore, SS induces detrimental effects on the mechanical integrity of healing PTs, and the response to RS was different between regenerate and residual tissues, the latter of which took longer period to reach NSS level.

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.

Immunohistochemical study of angiogenesis after local administration of platelet-rich plasma in a patellar tendon defect

A full thickness defect was made in the central portion of the patellar tendon of 48 New Zealand white rabbits. Platelet-rich plasma (PRP) gel was then applied and filled the tendon defect. The same procedure was performed in the control group, without the application of PRP. Animals were sacrificed after one, two, three, and four weeks. Histological and immunohistochemical analyses using a monoclonal antibody against CD31 were performed. The histological examination showed a superior healing process in the PRP group compared with the control group. Especially in the third week, the tissue formed in the PRP group was more mature and dense with less elastic fibres remaining. Neovascularisation was significantly higher in the PRP group during the first two weeks and significantly lower in the third and fourth weeks (p < 0.0001). Histological examination and study of angiogenesis showed that the application of PRP enhances and accelerates the tendon healing process.

Preoperative magnetic resonance assessment of patellar tendon dimensions for graft selection in anterior cruciate ligament reconstruction

BACKGROUND

A bone patellar tendon bone autograft is one of the standard graft choices for anterior cruciate ligament reconstruction. However, its use can be limited when the patellar tendon is too narrow or too long.

HYPOTHESIS

A preoperative assessment of patellar tendon dimensions using magnetic resonance imaging would be accurate and reliable. Patients undergoing anterior cruciate ligament reconstruction would have wide ranges of patellar tendon dimensions, and a significant proportion of patients would have a too narrow and/or too long patellar tendon as the graft choice. There would be a demographic predictor to identify the patients with inappropriate patellar tendon dimensions.

STUDY DESIGN

Cohort study (diagnosis); Level of evidence, 3.

METHODS

The accuracy and reliability of magnetic resonance assessments of patellar tendon dimensions were assessed by comparing the intraoperative measurements using a ruler in 55 knees and 10 knees, respectively. Data from the magnetic resonance assessments in 147 knees undergoing anterior cruciate ligament reconstruction were used for the normative documentation of the patellar tendon dimensions (width, thickness, and length) and identification of demographic predictors for the dimensions.

RESULTS

Preoperative magnetic resonance assessments of the patellar tendon dimensions were accurate and reliable. Korean patients undergoing anterior cruciate ligament reconstruction had wide variations in patellar dimensions, and a significant portion of the patients had an inappropriate patellar tendon (longer than 5 cm in 4.1% and narrower than 27 mm at middle portion in 15.6%) for the graft source. Patient height was the predictor used for patellar tendon width. The mathematical equation used to estimate the width based on patient height was: tendon width at middle portion (mm) = 0.202 x patient height (cm) - 5.07.

CONCLUSION

Preoperative magnetic resonance assessment of patellar tendon dimensions can be a valuable tool with satisfactory accuracy and reliability when the autologous patellar tendon is considered as the graft source for anterior cruciate ligament reconstruction.

Reconstruction of patellar tendon rupture after anterior cruciate ligament reconstruction: a case report

Patellar tendon rupture following use of its central third for anterior cruciate ligament (ACL) reconstruction is a rare disabling injury that is technically difficult to repair. We report one case of patellar tendon rupture after harvesting the mid-third for ACL reconstruction. A number of different surgical methods exist for reconstructing patellar tendon ruptures. Here we report a case using a bone-tendon-bone (BTB) allograft, followed by a multiple-wire loop reinforcement with no postoperative immobilisation. One year after operation, our patient had regained full knee extension and flexion. Insall Salvati index on the operated side was identical to the uninjured side. The patient had good quadriceps strength, and isokinetic muscle testing showed no deficit in his right leg. He was able to return to professional handball without limitation.

Low-intensity pulsed ultrasound on tendon healing: a study of the effect of treatment duration and treatment initiation

BACKGROUND

Low-intensity pulsed ultrasound has been reported to be effective in promoting tendon healing. However, its optimal time and duration has not yet been determined.

HYPOTHESIS

Tendons at different stages of healing may respond differently to low-intensity pulsed ultrasound. In the present study, the timing effects of low-intensity pulsed ultrasound on tendon healing were investigated in a rat model with a patellar tendon graft harvest lesion.

STUDY DESIGN

Controlled laboratory study.

METHODS

Sixty Sprague-Dawley rats underwent central third patellar tendon donor site harvest. Low-intensity pulsed ultrasound sonication was then delivered to the injured knees at day 1, 14, or 28 after harvest for 2, 4, or 6 weeks. Tendon samples were harvested at day 14, 28, and 42 after lesion for histological examination and mechanical testing.

RESULTS

A 2-week session of low-intensity pulsed ultrasound applied from day 1 postlesion (D1-2W) significantly improved the ultimate mechanical strength of the healing tendons from 23.1 +/- 8.5 MPa to 36.6 +/- 9.0 MPa. Low-intensity pulsed ultrasound did not improve healing when it was given at later stages in D15-2W and D29-2W. When low-intensity pulsed ultrasound treatment was extended from 2 weeks (D1-2W) to 4 weeks (D1-4W) or 6 weeks (D1-6W), the beneficial effects on tendon healing became insignificant. Histological examination showed that low-intensity pulsed ultrasound sonication at late healing stages may disturb remodeling with a poor collagen fiber alignment.

CONCLUSION

Low-intensity pulsed ultrasound promoted restoration of mechanical strength and collagen alignment in healing tendons only when applied at early healing stages.

CLINICAL RELEVANCE

The present findings indicate that low-intensity pulsed ultrasound may be an effective treatment to reduce tendon donor site morbidity.

A histological and ultrastructural evaluation of the patellar tendon 10 years after reharvesting its central third

PURPOSE

This study was undertaken to evaluate the histologic and ultrastructural characteristics of the patellar tendon 10 years after reharvesting its central third.

HYPOTHESIS

In the long term, after its central third is reharvested, the patellar tendon does not regain a normal histological and ultrastructural appearance.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Twelve consecutive patients (4 women, 8 men) who underwent anterior cruciate ligament revision surgery using reharvested ipsilateral patellar tendon autografts were included in the study. Percutaneous biopsy samples were obtained from the central and lateral parts of the patellar tendon under ultrasonographic guidance at a median of 116 months (range, 102-127 months) after the revision procedure. Eleven biopsy specimens from asymptomatic patellar tendons obtained from open anterior cruciate ligament reconstructions served as controls. The histologic characteristics and the presence of glycosaminoglycans were assessed using a light microscope, and the ultrastructure was assessed using a transmission electron microscope.

RESULTS

The histological evaluation revealed deterioration in fiber structure, increased cellularity, and increased vascularity in both the central and peripheral parts of the reharvested patellar tendon specimens compared with normal tendon specimens. No difference in the amount of glycosaminoglycans was seen in specimens from either part of the reharvested patellar tendons and the control specimens. The ultrastructural evaluation revealed that all the control specimens had a normal morphologic appearance and a compact extracellular matrix with regularly oriented collagen fibrils. Furthermore, in the control specimens, the fibril diameter was heterogeneous, with all fibril size classes present. Specimens from the central and the lateral part of the reharvested tendon displayed pathological cell appearance and a more heterogeneous extracellular matrix. The lateral specimens from the reharvested tendons also displayed all fibril size classes but with a more homogeneous distribution. In the central specimens, the largest fibril size class was absent.

CONCLUSION

Ten years after its central third was reharvested for anterior cruciate ligament revision surgery, the patellar tendon had not normalized in terms of its histological and ultrastructural appearance.

The incidence of acute patellar tendon harvest complications for anterior cruciate ligament reconstruction

PURPOSE

This study was performed to determine the incidence of acute bone-patellar tendon-bone autograft harvest complications after anterior cruciate ligament (ACL) reconstruction.

METHODS

Over a nearly 20-year period (September 1986 to April 2006), 1,725 consecutive patients underwent primary ACL reconstruction using bone-patellar tendon-bone autograft by 3 fellowship-trained sports medicine surgeons at our institution. Three acute complications related to patellar tendon harvest were identified from surgical databases, and the charts of these patients were reviewed.

RESULTS

In this series of 1,725 consecutive patients, 3 acute complications (0.2%) related to patellar tendon harvest were noted. These complications consisted of 2 patellar fractures (1 intraoperative and 1 postoperative) and 1 postoperative patellar tendon rupture. All 3 patients healed and went on to satisfactory outcomes.

CONCLUSIONS

A 0.2% overall acute complication rate related to patellar tendon harvest for primary ACL reconstruction supported our hypothesis. Bone-patella tendon-bone autograft remains a safe and viable choice for surgeons performing ACL reconstruction.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Anterior cruciate ligament reconstruction : quadriceps versus patellar autograft

The bone-patellar tendon-bone has been widely used and considered a good graft source. The quadriceps tendon was introduced as a substitute graft source for bone-patellar tendon-bone. We compared the clinical outcomes of anterior cruciate ligament reconstructions using central quadriceps tendon-patellar bone and bone-patellar tendon-bone autografts. We selected 72 patients who underwent unilateral anterior cruciate ligament reconstruction using bone-patellar tendon-bone between 1994 and 2001 and matched for age and gender with 72 patients who underwent anterior cruciate ligament reconstruction using quadriceps tendon-patellar bone. All patients were followed up for more than 2 years. We assessed anterior laxity, knee function using the Lysholm and International Knee Documentation Committee scores, and quadriceps strength, the means of which were similar in the two groups. More patients (28 or 39%) in the bone-patellar tendon-bone group reported anterior knee pain than in the quadriceps tendon-patellar bone group (six patients or 8.3%). Anterior cruciate ligament reconstruction using the central quadriceps tendon-patellar bone graft showed clinical outcomes comparable to those of anterior cruciate ligament reconstruction using the patellar tendon graft, with anterior knee pain being less frequent in the former. Our data suggest the quadriceps tendon can be a good alternative graft choice.

LEVEL OF EVIDENCE

Level III Therapeutic study.

Clinical outcomes of allograft versus autograft in anterior cruciate ligament reconstruction

Anterior cruciate ligament (ACL) injuries are the most common complete ligamentous injury to the knee. The optimal graft should be able to reproduce the anatomy and biomechanics of the ACL, be incorporated rapidly with strong initial fixation, and cause low graft-site morbidity. This article reviews the literature comparing the clinical outcomes following allograft and autograft ACL reconstruction and examines current issues regarding graft choice.