Minimally Invasive Quadriceps Tendon Single-Bundle, Arthroscopic, Anatomic Anterior Cruciate Ligament Reconstruction With Rectangular Bone Tunnels

Rectangular-Tunnel Anterior Cruciate Ligament Reconstruction Using Quadriceps Tendon-Patellar Bone Autograft Can Reduce Early Donor Site Morbidity While Maintaining Comparable Short-term Clinical Outcomes

Background

Rectangular tunnel and graft have been recently designed to closely resemble the native anatomy in anterior cruciate ligament reconstruction (ACLR). This study was performed to compare the short-term clinical outcomes between rectangular and round femoral tunnels in ACLR using quadriceps tendon-patellar bone (QTPB) autografts.

Methods

A total of 78 patients who underwent primary ACLR with QTPB autografts performed by three senior surgeons and had at least 1 year of postoperative follow-up were retrospectively reviewed. Patients who underwent rectangular tunnel ACLR (n = 40) were compared to those treated with the conventional round tunnel ACLR (n = 38). Outcomes including knee stability, clinical scores, quadriceps strength, associated complications, postoperative knee range of motion, and cross-sectional area of the graft were assessed.

Results

Significant improvements in knee stability and clinical scores were observed after surgery in both groups (all p < 0.001). The postoperative measurements of knee stability and clinical scores were not significantly different between the two groups. Knee extension strength deficit at 60°/sec was significantly less in the rectangular tunnel group than in the round tunnel group at postoperative 6 months (41.7% vs. 48.9%, p = 0.032). The cross-sectional area of the partial-thickness QTPB graft was approximately 60% of the full-thickness QTPB graft.

Conclusions

In the short-term, rectangular tunnel ACLR was comparable to round tunnel ACLR with QTPB autograft despite the smaller cross-sectional area. Additionally, the rectangular tunnel ACLR allowed partial-thickness grafting technique, which could subsequently reduce early donor site morbidity.

Revision ACL reconstruction using quadriceps, hamstring and patellar tendon autografts leads to similar functional outcomes but hamstring graft has a higher tendency of graft failure

PURPOSE

The purpose of this study was to evaluate the differences in the patient-reported functional outcomes, and graft failure in revision ACL reconstruction using quadriceps tendon (QT), Hamstring tendon (HT) and bone-patellar tendon-bone (BPTB) autografts.

METHODS

Between 2010 and 2020, 97 patients who underwent revision ACL reconstruction (40 patients received a QT, 26 an HT and 31 a BPTB graft) met the inclusion criteria. Pre-injury and at 2-year postoperatively patients were evaluated for patient-reported functional outcomes; Lysholm knee score, Tegner activity level and VAS (visual analogue scale) for pain; and graft failure. Patient-reported outcomes and graft failure were compared between the QT, HT and BPTB groups. The patients with graft failure were not included for outcome analysis at 2-years of follow-up.

RESULTS

All three revision groups with QT, HT and BPTB autograft did not differ significantly in terms of age, sex, time from injury to surgery, concomitant injuries and single-stage or double-stage procedures (n.s.). No significant difference was found in the pre-injury patient-reported outcome; Lysholm knee score, Tegner activity and VAS for pain (n.s.) between the three groups. At the 2-year follow-up functional outcomes improved in all three groups and all the patients returned to pre-injury activity level; however, no significant difference was found in functional outcomes at the 2-year follow-up between the three groups (n.s.). Graft failure occurred in 4 (10%), 5 (19%) and 3 (10%) patients of QT, HT and BPTB groups, respectively. However, the rate of failure did not differ significantly between groups.

CONCLUSION

All three autografts (QT, HT and BPTB) demonstrated satisfactory patient-reported outcomes in revision ACL reconstruction. Compared with QT and BPTB grafts, HT graft showed a higher tendency for failure rates. With the increasing incidence of revision ACL reconstruction, surgeons should be aware of all the available graft options. The findings of this study will assist the surgeons in the graft selection for revision ACL reconstruction.

LEVEL OF EVIDENCE

Level III.

Quadriceps autograft is a viable graft choice for arthroscopic ACL reconstruction in patients over 50 years of age

PURPOSE

The purpose of this study was to evaluate the patient-reported outcomes, graft failure, quadriceps rupture and sports preference after arthroscopic ACL reconstruction in patients older than 50 years who underwent arthroscopic ACL reconstruction with a quadriceps tendon (QT) autograft.

METHODS

Between 2010 and 2020, prospectively collected data were obtained from an institutional database. Patients older than 50 years with primary arthroscopic ACL reconstruction and a minimum of 2 years of follow-up were included. Patients undergoing a revision ACL reconstruction or undergoing a primary ACL reconstruction using a graft other than a QT autograft, and patients with a contralateral knee injury or osteoarthritis (Ahlbäck stage 2 or higher) were excluded. A minimally invasive technique was used for QT autograft harvesting. Patients were evaluated for pre-injury and 2-year follow-up Lysholm knee score, Tegner activity level, Visual Analog Scale (VAS) for pain, graft failure, quadriceps tendon rupture, and return to sport.

RESULTS

A total of 57 patients were included in the study. The mean age of the cohort was 54.9 ± 5.2 (range 50-75). Of the 57 reconstructions, 16 (28%) were isolated ACL reconstructions, while 41 (72%) were complex reconstructions (concomitant meniscus, cartilage and/or collateral ligament injuries). At the 2-year follow-up Lysholm knee score, Tegner activity level and VAS for pain improved to pre-injury level and no significant difference was noted between pre-injury and 2-year follow-up functional scores (n.s.). No case of graft failure or quadriceps tendon rupture was reported. No significant difference was noted in the pre-injury and postoperative sports preference (n.s.) and all patients return to their desired sports activity.

CONCLUSION

Arthroscopic ACL reconstruction by using QT autograft in highly active older patients provides satisfactory patient-reported functional outcomes and allows recovery of the pre-injury level of activity. QT autograft is a good graft option in patients older than 50 years.

LEVEL OF EVIDENCE

Level IV.

Strategies to promote tendon-bone healing after anterior cruciate ligament reconstruction: Present and future

At present, anterior cruciate ligament (ACL) reconstruction still has a high failure rate. Tendon graft and bone tunnel surface angiogenesis and bony ingrowth are the main physiological processes of tendon-bone healing, and also the main reasons for the postoperative efficacy of ACL reconstruction. Poor tendon-bone healing has been also identified as one of the main causes of unsatisfactory treatment outcomes. The physiological process of tendon-bone healing is complicated because the tendon-bone junction requires the organic fusion of the tendon graft with the bone tissue. The failure of the operation is often caused by tendon dislocation or scar healing. Therefore, it is important to study the possible risk factors for tendon-bone healing and strategies to promote it. This review comprehensively analyzed the risk factors contributing to tendon-bone healing failure after ACL reconstruction. Additionally, we discuss the current strategies used to promote tendon-bone healing following ACL reconstruction.

Return to Play and Pattern of Injury After ACL Rupture in a Consecutive Series of Elite UEFA Soccer Players

Background

Anterior cruciate ligament rupture represents a career-threatening injury for professional soccer players.

Purpose

To analyze the pattern of injury, return to play (RTP), and performance of a consecutive series of elite professional soccer players after anterior cruciate ligament reconstruction (ACLR).

Study Design

Case series; Level of evidence, 4.

Methods

We evaluated the medical records of 40 consecutive elite soccer players who underwent ACLR by a single surgeon between September 2018 and May 2022. Patient age, height, weight, body mass index, position, injury history, affected side, RTP time, minutes played per season (MPS), and MPS as a percentage of playable minutes before and after ACLR were retrieved from medical records and from publicly available media-based platforms.

Results

Included were 27 male patients (mean ± SD age at surgery, 23.2 ± 4.3 years; range, 18-34 years). The injury occurred during matches in 24 players (88.9%), with a noncontact mechanism in 22 (91.7%). Meniscal pathology was found in 21 patients (77.8%). Lateral meniscectomy and meniscal repair were performed in 2 (7.4%) and 14 (51.9%) patients, respectively, and medial meniscectomy and meniscal repair were performed in 3 (11.1%) and 13 (48.1%) patients, respectively. A total of 17 players (63.0%) underwent ACLR with bone-patellar tendon-bone autograft and 10 (37.0%) with soft tissue quadriceps tendon. Lateral extra-articular tenodesis was added in 5 patients (18.5%). The overall RTP rate was 92.6% (25 of 27). Two athletes moved to a lower league after surgery. The mean MPS% during the last preinjury season was 56.69% ± 21.71%; this decreased significantly to 29.18% ± 20.6% (P < .001) in the first postoperative season and then increased to 57.76% ± 22.89% and 55.89% ± 25.8% in the second and third postoperative seasons. Two (7.4%) reruptures and 2 (7.4%) failed meniscal repairs were reported.

Conclusion

ACLR in elite UEFA soccer players was associated with a 92.6% rate of RTP and 7.4% rate of reinjury within 6 months after primary surgery. Moreover, 7.4% of soccer players moved to a lower league during the first season after surgery. Age, graft selection, concomitant treatments, and lateral extra-articular tenodesis were not significantly associated with prolonged RTP.

Posterior Cruciate Ligament Reconstruction Using Flat Soft-Tissue Grafts

Isolated posterior cruciate ligament (PCL) ruptures are relatively rare, but they more commonly occur in multiligament knee injuries. To date, in isolated or combined injuries with grade III step-off, surgical treatment is recommended to restore joint stability and improve knee function. Several techniques for PCL reconstruction have been described. However, recent evidence has suggested that broad, flat soft-tissue grafts may more closely mimic the native PCL ribbonlike morphology in PCL reconstruction. Furthermore, a femoral rectangular bone tunnel may more accurately re-create the native PCL attachment, allowing grafts to simulate native PCL rotation during knee flexion and potentially improving biomechanics. Therefore, we have developed a PCL reconstruction technique using flat quadriceps or hamstring grafts. This technique can be performed using 2 types of surgical instruments that allow for the creation of a rectangular femoral bone tunnel.

Anatomic anterior cruciate ligament reconstruction: Freddie Fu's paradigm

Anterior cruciate ligament (ACL) reconstruction techniques have evolved over the past four decades. There is evidence that non-anatomic reconstruction techniques, such as traditional transtibial drilling, fail to recreate the native anatomy of the ACL, which can lead to increased rotatory knee instability, revision risk, and post-traumatic osteoarthritis. Anatomic ACL reconstruction has emerged as the gold standard, with the goal of restoring the patient's native anatomy and knee kinematics. This review will summarise the relevant anatomy, modern anatomic ACL reconstruction techniques, and literature supporting anatomic ACL reconstruction as the new paradigm. LEVEL OF EVIDENCE: Level V, review article.

Quadriceps tendon autograft with or without bone block have comparable clinical outcomes, complications and revision rate for ACL reconstruction: a systematic review

PURPOSE

The purpose of this systematic review is to report complications, graft failure, fixation methods, rehabilitation protocol, clinical and patient-reported outcomes, and return to sports with the use of quadriceps tendon graft with the bone block (QT-B) and without bone block (QT-S).

METHODS

According to the PRISMA guidelines a comprehensive search was performed across PubMed/MEDLINE, Scopus, EMBASE, and Cochrane Library databases from inception until April 2022. Only prospective studies using quadriceps tendon autograft with a minimum of 20 patients were considered for inclusion. The outcome measures extracted from the studies were the KT-1000, Lysholm score, Subjective and Objective IKDC, Tegner, Marx Score, complications, failures and/or revision surgery, and rate of return to sports. Cochrane risk of bias and MINORS tool were used for the risk of bias assessment of all included studies.

RESULTS

A total of 13 studies were included, consisting of 5 randomized controlled trials, 6 cohort studies, 1 case-control and 1 case series. A total of 484 patients received QT-S in 6 studies of which 224 (46.2%) were males and 212 (43.8%) females with a mean age of 21.5 ± 7.5 (range 14-58). While 243 patients received QT-B in 7 studies of which 167 (68.7%) were males and 76 (31.3%) females with a mean age of 28.9 ± 4.5 (range: 18-49). The studies analyzed had a mean MINORS score of 14.6 (range, 12-19). Both QT-B and QT-S for ACL reconstruction reported satisfactory results in terms of patient-reported outcome measures. Although, a slightly higher anterior laxity was found with the QT-S than with the QT-B.

CONCLUSION

Quadriceps tendon with a bone block (QT-B) or without bone block (QT-S) for ACL reconstruction is supported by current literature. Both grafts are safe and viable options for ACL reconstruction with comparable clinical outcomes, complications and revision rates.

LEVEL OF EVIDENCE

Level IV.

REGISTRATION

PROSPERO-CRD42022347134; https://www.crd.york.ac.uk/prospero/.

In vivo knee rotational stability 2 years after the ACL reconstruction using a quadriceps tendon graft with bone block and bone-patellar tendon-bone graft

INTRODUCTION

The aim of this prospective randomised study was to evaluate clinical results and rotational stability at least 2 years after single-bundle anatomic anterior cruciate ligament reconstruction using a quadriceps tendon graft with bone block (BT) and bone-patellar tendon-bone graft (BTB).

MATERIALS AND METHODS

In both groups (BT and BTB), 40 patients selected prospectively at random were evaluated. The mean follow-up after the surgery was 28 months (range 24-33 months). A navigation system was used to measure rotational stability of the knee joint. Cincinnati, Lysholm, and IKDC scores and visual analog score (VAS) were used to evaluate clinical results and the non-parametric Wilcoxon test was used for the statistical analysis.

RESULTS

After the BT reconstruction, the mean internal rotation of the tibia (IR) was 9.5°. In the contralateral healthy knee joint, IR was 8.6° at average. After the BTB reconstruction, the mean IR was 9.9°. In the contralateral healthy knee joint, IR was 8.7° at average. We did not find any statistically significant difference in IR stability between BT and BTB reconstruction. In terms of clinical results, regarding the VAS, patients perceive significantly more pain after the BTB reconstruction (p < 0.05). Kneeling was reported more difficult and painful after BTB reconstruction.

CONCLUSIONS

The BT reconstruction of the ACL provides similar clinical results, less pain, better flexion and the same rotational stability of the knee in comparison with the BTB reconstruction.

Anterior cruciate ligament reconstruction using quadriceps tendon autograft is a viable option for small-statured female patients

PURPOSE

The choice of graft for anterior cruciate ligament (ACL) reconstruction remains controversial. The quadriceps tendon (QT) autograft is a good alternative for ACL reconstruction. However, concerns regarding its use in short-statured patients, related to donor site morbidity, anterior knee pain, or loss of muscle strength remain. This study aimed to compare muscle strength and morbidity between patients with short and normal statures following ACL reconstruction with a QT autograft.

METHODS

A total of 73 female patients (mean age, 33.8 ± 11.5 years) who underwent primary ACL reconstruction between 2016 and 2019 were included. Patients were categorized into two groups: group S, with a height ≤ 163 cm, and group L, with a height > 163 cm. Muscle strength, harvesting site morbidity, and ACL-return to sport after injury scale (ACL-RSI) were evaluated, with a mean timing of the follow-up of 9.0 ± 2.3 months.

RESULTS

The mean quadriceps strength for the isokinetic measurements at 60° and 240° was 65.0% and 74.0% in group S, respectively, and 70.0% and 75.7% in group L, respectively. There was no significant difference in the postoperative muscle strength or mean ACL-RSI (group S, 70.0; group L, 65.9) between the groups. No donor site morbidity was observed in either group.

CONCLUSION

Muscle strength recovery, morbidity, and readiness to return to sports were similar in both groups, which supports the possibility of QT autografts for patients with a small stature. The results of this study may provide useful information for surgeons who are hesitant to perform QT autografts because of patient physique.

LEVEL OF EVIDENCE

IV.

Patellar Size Variation at the Quadriceps Tendon-Bone Block Harvest Site: A Magnetic Resonance Imaging Study to Evaluate the Safe Zone for Harvesting a Sufficient Bone Block

BACKGROUND

Quadriceps tendon (QT) autografts with and without a bone block are the least studied and least used options for anterior cruciate ligament reconstruction surgery. In particular, there is a lack of literature describing patellar anatomy. Until now, guidelines for patellar bone block harvesting have been based solely on personal experience. In this study, we intended to derive recommendations from physical regularities and objective criteria.

PURPOSE

To determine the maximal, individual-related length and depth of the bone block that can be safely harvested and to provide guidelines to help surgeons make decisions on graft choice.

STUDY DESIGN

Descriptive laboratory study.

METHODS

The study group consisted of 50 male participants and 50 female participants (mean age, 29.4 ± 7.9 years) who underwent 3.0-T magnetic resonance imaging of their knee. Patellar height was determined at the center of the middle third of the QT insertion on the patella and the medial and lateral endpoints; the depth was measured at the midpoints of the respective heights.

RESULTS

The mean width of the QT and the mean thickness were 49.0 ± 7.6 and 7.3 ± 1.0 mm, respectively. The mean patellar thickness in reference to the medial endpoint, the center, and the lateral endpoint was 18.3 ± 2.4, 17.9 ± 2.3, and 15.1 ± 2.3 mm, respectively, whereas the mean patellar height was 35.1 ± 4.1, 36.7 ± 4.2, and 35.1 ± 3.9 mm. In general, the tendon and patellar dimensions were significantly larger in male participants than in female participants (P = .016).

CONCLUSION

Bone block harvesting, with its depth not exceeding 50% of the patellar thickness and its length accounting for <50% of the patellar height, poses the least risk for a patellar fracture when located medial to midline. If the bone block is excised from the medial half of the central area (the latter is defined by the middle third of the QT insertion), with the outer edge of the saw positioned at the medial border of the central area, a graft of 15 mm length, 10 mm width, and 8 mm depth can be safely harvested in all White male participants and almost all female participants taller than 165 cm, according to our findings.

CLINICAL RELEVANCE

This is the first study presenting recommendations for patellar bone block harvesting at the quadriceps tendon insertionbased on physical regularities and objective criteria and not on personal experience.

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.

Technical note: rectangular femoral tunnel for anterior cruciate ligament reconstruction using a new ultrasonic device: a feasibility study

PURPOSE

The goal of this preliminary report was to show the use of novel Ultrasound (US) technology for anterior cruciate ligament (ACL) reconstruction surgery and evaluate its feasibility for the creation of a rectangular femoral bone tunnel during an arthroscopic procedure in a human cadaver model.

METHODS

Two fresh frozen human cadaver knees were prepared for arthroscopic rectangular femoral tunnel completion using a prototype US device (OLYMPUS EUROPA SE & CO. KG). The desired rectangular femoral tunnel was intended to be located in the femoral anatomical ACL footprint. Its tunnel aperture was planned at 10 × 5 mm and a depth of 20 mm should be achieved. For one knee, the rectangular femoral tunnel was realized without a specific cutting guide and for the other with a 10 × 5 mm guide. One experienced orthopedic surgeon performed the two procedures consecutively. The time for femoral tunnel completion was evaluated. CT scans with subsequent three-dimensional image reconstructions were performed in order to evaluate tunnel placement and configuration.

RESULTS

In the two human cadaver models the two 10 × 5x20mm rectangular femoral tunnels were successfully completed and located in the femoral anatomical ACL footprint without adverse events. The time for femoral tunnel completion was 14 min 35 s for the procedure without the guide and 4 min 20 s with the guide.

CONCLUSION

US technology can be used for the creation of a rectangular femoral bone tunnel during an arthroscopic ACL reconstruction procedure. The use of a specific cutting guide can reduce the time for femoral tunnel completion. Additional experience will further reduce the time of the procedure.

Comparing Knee Laxity After Anatomic Anterior Cruciate Ligament Reconstruction Using Quadriceps Tendon Versus Semitendinosus Tendon Graft

Background:

The choice of graft in anterior cruciate ligament (ACL) reconstruction is still under discussion. The hamstrings are currently the most used grafts for primary ACL reconstruction in Europe. However, increased interest has arisen in the quadriceps tendon (QT) as an alternative autologous graft option for primary ACL reconstruction.

Purpose:

To evaluate knee stability and the subjective outcome after ACL reconstruction using either autologous QT graft in implant-free femoral press-fit fixation technique or semitendinosus tendon (ST) graft.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

We evaluated 50 patients who underwent ACL reconstruction, including 25 patients who received autologous ipsilateral QT graft (QT group) and 25 patients who received the ipsilateral ST graft (ST group). The follow-up for this prospective comparative study was at least 2 years after surgery, comprising KT-1000 arthrometer testing, pivot-shift test, Knee injury and Osteoarthritis Outcome Score (KOOS), Lysholm score, and rerupture rate.

Results:

The mean patient age was 31.72 years (9 women, 16 men) in the QT group and 32.08 years (13 women, 12 men) in the ST group. The mean ± standard deviation postoperative side-to-side difference assessed using KT-1000 arthrometer was 1.56 ± 1.56 mm for the QT group and 1.64 ± 1.41 mm for the ST group, with no significant difference. No significant difference was found on any of the KOOS subscale scores (P = .694) or the Lysholm score (P = .682). No rerupture or positive pivot-shift test occurred during follow-up. No difference was found in donor-site morbidity between the study groups.

Conclusion:

Clinical outcomes were not significantly different between QT and ST grafts in the current study. Thus, the QT may serve as a good alternative graft for primary ACL reconstruction.

Evolution in ACL Autograft Harvesting Techniques: Transition to Minimally Invasive Autograft Harvesting

Surgical techniques for anterior cruciate ligament (ACL) reconstruction continue to evolve. Harvesting techniques for commonly used ACL autografts such as bone patellar tendon bone, hamstring, and quadriceps tendon have similarly continued to progress. Traditional larger incisions for graft harvesting that were described in the 1980s have given way to smaller or more minimally invasive techniques. Advantages of these techniques are primarily anatomy based and include the following: decreased nerve complaints such as hypoesthesia or dysesthesia, improved cosmesis, decreased surgical site pain or morbidity, and, in the case of hamstring harvesting, easier tendon identification. The current literature supports reproducible minimally invasive or modified graft harvesting techniques for bone patellar tendon bone, hamstring, and quadriceps tendon autografts. Specialized instrumentation is available to simplify the harvesting process. Each of these techniques is described in detail outlining surgical steps, technical considerations, and precautions. Knowledge and review of these techniques provides the surgeon with greater flexibility and options when choosing and harvesting autograft tissue for ACL reconstruction.

A Bone-Hamstring Autograft for Arthroscopic Anterior Cruciate Ligament Reconstruction

We describe a bone-hamstring autograft for anterior cruciate ligament reconstruction (ACLR). The semitendinosus and gracilis tendons are harvested using an open tendon stripper, keeping these distal tibial insertions intact. The bone-hamstring autograft is harvested using an oscillating saw. This modified autograft has the following advantages: (1) It possesses the potential for healing with the femur owing to its bone plug; (2) it is perfectly suited for various single-bundle reconstruction methods including oval-tunnel and rectangular-tunnel ACLR, as well as other flat ACLR methods; and (3) it is an attractive option for both primary ACLR and revision ACLR owing to its unique characteristics.

Viscoelastic and failure properties of two configurations of triple-folded hamstring tendons used for anterior cruciate ligament (ACL) reconstruction

BACKGROUND

Hamstring autografts are commonly used for anterior cruciate ligament (ACL) reconstruction. Different folding techniques exist in tripling the semitendinosus. Few anatomical studies exist in evaluating their viscoelastic properties. The purpose of this study was to characterize and compare the viscoelastic and failure properties of two hamstring graft configurations, the "Z" construct and "2" construct.

METHODS

Ten matched pairs of fresh-frozen cadaveric semitendinosus hamstring grafts were used to create the "2" configuration or "Z" configuration. The biomechanical testing consisted of four phases: preconditioning, where graft dimensions (mm) were measured; stress relaxation, where load, displacement and time data were collected and equilibrium relaxation (%) was calculated; dynamic creep, where the total construct elongation was calculated; and ramp-to-failure, where maximum failure load was recorded.

RESULTS

The "2" configuration demonstrated recorded forces (N) significantly greater at each time point when compared to the "Z" configuration during stress relaxation (p = 0.003). The "2" configuration exhibited significantly less construct elongation (mm) during dynamic creep at 10 cycles (p = 0.008) and 2000 cycles (p = 0.0001). The maximum measured load at failure was significantly greater in the "2" configuration constructs than "Z" configuration (p = 0.013). Moreover, the axial loads at 2, 3 and 4 mm of displacement were, on average, greater in the "2" configuration than "Z" configuration (p = 0.152; p = 0.080; p = 0.012), respectively.

CONCLUSION

The results of this study provide support for folding techniques for tripled grafts to provide higher viscoelastic and failure properties for techniques with less suture interfaces. Future studies can potentially evaluate the clinical significance of these findings.

Differences in the Development of Fibrocartilage Layers in the Quadriceps Tendon and Patellar Tendon Insertions in Rabbits: A Quantitative Study

Background

Differences in the development of fibrocartilage layers in quadriceps tendon (QT) and patellar tendon (PT) insertion sites are unclear. Because the mechanical environments for the QT and PT are different, the development of the QT and PT insertions may differ.

Purpose

To investigate differences in the development of fibrocartilage layers in the QT and PT insertion sites in rabbits through use of quantitative morphometric evaluations.

Study Design

Descriptive laboratory study.

Methods

This study included 54 male Japanese White rabbits. Animals were euthanized at ages 1 day and 1, 2, 3, 4, 6, 8, 12, and 24 weeks (n = 6 for each age). Chondrocyte number, proliferation, apoptosis, sex-determining region Y box 9 (Sox9)-positive rates, safranin O-stained glycosaminoglycan (GAG) areas, tidemark length, insertion width, and patellar length were evaluated and compared with the same parameters at age 24 weeks and between QT and PT insertion sites.

Results

Chondrocyte proliferation was low up to age 2 weeks for QT insertion and low up to 1 week for PT insertion. Chondrocyte apoptosis was high at 1 day and Sox9 expression was low up to 1 week for PT insertion. Sox9 expression was higher in QT than in PT insertion at age 12 weeks. The high chondrocyte count continued to age 1 day in PT insertion and up to 6 weeks in QT insertion. The chondrocyte number was higher in QT than in PT insertion at age 2 weeks. The period of thicker GAG lasted from 2 to 8 weeks in PT insertion and from 1 to 12 weeks in QT insertion. GAG thickness in QT insertion was higher than in PT insertion at age 4 and 12 weeks.

Conclusion

Development of fibrocartilage layers in QT and PT insertion sites was completed at age 24 weeks in rabbits. However, the period of high chondrocyte count and period of thicker GAG were longer in QT than in PT insertion up to 12 weeks.

Clinical Relevance

Development of fibrocartilage layers in QT and PT insertions differed in rabbits. Our results may contribute to the development of appropriate treatments based on age and the development of methods for regeneration of the insertion.

Patient-Reported Knee Outcome Scores With Soft Tissue Quadriceps Tendon Autograft Are Similar to Bone-Patellar Tendon-Bone Autograft at Minimum 2-Year Follow-up: A Retrospective Single-Center Cohort Study in Primary Anterior Cruciate Ligament Reconstruction Surgery

Background:

Quadriceps tendon (QT)–bone autografts used during anterior cruciate ligament (ACL) reconstruction have provided comparable outcomes and decreased donor-site morbidity when compared with bone–patellar tendon–bone (BPTB) autografts. No study has directly compared the outcomes of the all–soft tissue QT autograft with that of the BPTB autograft.

Hypothesis:

Patient-reported knee outcome scores and rates of postoperative complication after primary ACL reconstruction with QT autografts are no different from BPTB autografts at a minimum 2-year follow-up.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 75 patients who underwent primary autograft ACL reconstruction with QT or BPTB autografts between January 1, 2015, and March 31, 2016, at a single hospital center were contacted by telephone and asked to complete the International Knee Documentation Committee (IKDC) Subjective Knee Evaluation, Tegner activity level scale, and Lysholm knee scoring scale. Information about the subsequent surgeries performed on the operative knee was also collected. Statistical analysis was performed using the Kruskal-Wallis test and the Fisher exact test for categorical data.

Results:

Fifty patients (28 QT, 22 BPTB) completed the surveys at a mean follow-up of 33.04 months (range, 24-44 months). For the QT versus the BPTB group respectively, the median IKDC scores were 94.83 (interquartile range [IQR], 7.61) versus 94.83 (IQR, 10.92) (P = .47), the median Tegner scores were 6 (IQR, 2.5) versus 6 (IQR, 2.75) (P = .48), and the median Lysholm scores were 95 (IQR, 9) versus 95 (IQR, 13) (P = .27). Additionally, 2 QT patients and 3 BPTB patients required follow-up arthroscopy for arthrolysis (P = .64). There was 1 graft failure in the QT group requiring revision surgery.

Conclusion:

There was no statistical difference in patient-reported knee outcomes or graft complication rates between the QT and BPTB autograft groups at a minimum 2-year follow-up after primary ACL reconstruction. This study highlights that the all–soft tissue QT autograft may be a suitable graft choice for primary ACL reconstruction.

A more flattened bone tunnel has a positive effect on tendon-bone healing in the early period after ACL reconstruction

PURPOSE

The purpose of this study was to evaluate whether a flattened bone tunnel has a positive effect on the tendon-bone healing (TBH) process in the early period after anterior cruciate ligament (ACL) reconstruction.

METHODS

Seventy-two New Zealand White rabbits were randomly allocated into two groups, the flattened tunnel (FT) group and the conventional round tunnel (RT) group. We compared the cross-sectional areas and diameters of the bone tunnels between the two groups through computed tomography (CT) scanning. TBH results between the two groups were assessed by histological analysis, micro-CT scanning and biomechanical tests at 4 weeks, 8 weeks and 12 weeks after operation.

RESULTS

The cross-sectional areas of the bone tunnels between the two groups were almost the same. However, the shape of bone tunnels in the FT group was more flattened. A faster cellular and collagen remoulding process were found in the FT group. Semiquantitative histological analysis of Safranin O staining showed that there was more fibrocartilage formation in the interface region in the FT group (P < 0.05). Sirius Red staining showed that the tissues in the interface areas were more intense in the FT group. Micro-CT scanning showed that more new bone formation could be found in the interface region in the FT group. The biomechanical tests also showed that FT ACL reconstruction will result in a stronger regenerated tendon-bone interface.

CONCLUSIONS

Our study found that a flattened bone tunnel accelerated TBH in the early period after ACL reconstruction surgery in a rabbit model, which lays the groundwork for further clinical practice of this ACL reconstruction method.