Revision anterior cruciate ligament reconstruction: an update

Clinical Outcomes of Single-Stage Revision Anterior Cruciate Ligament Reconstruction Using a Fast-Setting Bone Graft Substitute

Revision anterior cruciate ligament reconstruction (ACLR) can be achieved in a single-stage or two-stage approach. Single-stage revisions have several advantages, including one less operation, decreased cost, and a quicker recovery for patients. Revision ACLR can be complicated by malpositioned or dilated bone tunnels, which makes a single-stage revision more challenging or sometimes necessitates a two-stage approach. The use of fast-setting bone graft substitutes (BGS) has been described in recent literature as a strategy to potentially help address this problem in the setting of single-stage revision ACLR. The aim of this study was to evaluate patient-reported clinical outcomes of patients who have undergone single-stage revision ACLR using fast-setting BGS to address prior malpositioned or dilated tunnels. A retrospective review was conducted of the first nine consecutive patients who had undergone single-stage revision ACLR using a fast-setting BGS by a single surgeon between May 2017 and February 2020 with a minimum of 2-year follow-up. Patient-reported clinical outcomes, including the International Knee Documentation Committee (IKDC) questionnaire, the Tegner Lysholm Knee Scoring Scale, patient satisfaction questions, and the need for additional surgery were evaluated for this group between 26 and 49 months postoperative. Of the nine patients eligible for inclusion, eight patients (88.9%) were evaluated, and one was lost to follow-up. At an average follow-up of 37.9 months (range: 27.8-55.7), the mean postoperative IKDC score was 75.0 ± 11.3, and the mean postoperative Tegner Lysholm Knee Score was 83.0 ± 17.6. None of the patients required additional revision surgery or experienced construct failure at the time of follow-up. Seven of eight respondents (87.5%) had their preoperative expectations met with the surgery, and 100% of patients stated they would have the surgery again. Single-stage revision ACLR using fast-setting BGS showed overall positive clinical outcomes for this pilot group of patients at a minimum 2-year follow-up. In select revision scenarios, these materials may be a valuable option to allow the filling of defects without compromising fixation or clinical outcomes.

Revision ACL reconstruction in female athletes: current concepts

The challenge of revision anterior cruciate ligament (ACL) reconstruction lies in its complexity, varied presentation, and technical intricacies. A successful ACL reconstruction should allow patients to safely return to preinjury activities. However, it is only sometimes simple, and many risk factors and concurrent pathologies come into play. Evaluating and analysing the cause of failure and associated conditions is paramount to addressing them effectively. Despite a plethora of research and improvements in knowledge and technology, e gaps exist in issues such as optimal techniques of revision surgery, graft options, fixation, concurrent procedures, rehabilitation and protocol for return to sports of high-level athletes. Female athletes need additional focus since they are at higher risk of re-injury, suboptimal clinical outcomes, and lower rates of return to sport following revision reconstruction. Our understanding about injury prevention and the protection of ACL grafts in female athletes needs to be improved. This review focuses on the current state of revision ACL surgery in female athletes and provides recommendations and future directions for optimising outcomes in this high-risk group.

PEEK Interference Screws Show Significant Tunnel Enlargement After ACL Reconstruction and is Comparable to Adjustable-Length Loop Cortical Button Fixation

Background

It is unclear whether the use of polyetheretherketone (PEEK) interference screws for anterior cruciate ligament (ACL) reconstruction leads to postoperative tunnel enlargement. Femoral tunnel enlargement was further compared with adjustable-length loop cortical fixation.

Methods

Eighteen patients with ACL reconstruction using hamstring grafts were retrospectively divided into two groups. Eleven patients were treated with the ACL reconstruction technique using a PEEK interference screw for femoral graft fixation. Seven patients received adjustable-length loop cortical buttons for femoral fixation. Tibial ACL graft fixation was performed using PEEK interference screws. Tunnel volume changes were assessed using computed tomography (CT) scans performed after surgery (100%) and after 1 year. The maximal tunnel diameter was measured.

Results

The group with femoral screw fixation showed a mean tunnel volume change of 108.15 ± 13.7% on the tibial side and 124.07 ± 25.38% on the femoral side. The group with femoral button fixation showed a tunnel volume change of 111.12 ± 12.72% on the tibial side and 130.96 ± 21.71% on the femoral side. The differences in femoral tunnel volume changes were not significant (P = 0.562). Femoral tunnels with PEEK screw fixation showed significantly larger diameter after 12 months in comparison with button fixation (13.02 ± 1.43 mm vs. 10.46 ± 1.29 mm, P < 0.001).

Conclusions

PEEK interference screws were associated with significant tibial and femoral tunnel enlargement. Femoral tunnel enlargement was comparable between PEEK interference screws and button fixation. Final femoral tunnel diameter was significantly larger with PEEK screw fixation in comparison to button fixation.

Tunnel widening after ACL reconstruction with different fixation techniques: aperture fixation with biodegradable interference screws versus all-inside technique with suspensory cortical buttons. 5-year data from a prospective randomized trial

BACKGROUND

The aim of the present study was to examine tunnel widening and clinical outcomes after anterior cruciate ligament reconstruction (ACLR) using two different fixation methods: aperture fixation with biodegradable interference screws versus all-inside ACLR with suspensory cortical buttons.

METHODS

Tunnel widening was assessed using volumetric and diameter measurements on magnetic resonance imaging (MRI) scans directly after surgery, as well as 6 months and 2 and 5 years postoperatively. Clinical outcomes were assessed after 5 years with instrumented tibial anteroposterior translation measurement (KT-1000), single-leg hop testing, and the IKDC, Lysholm, and Tegner activity scores.

RESULTS

At the final follow-up, the study population consisted of 21 patients, 12 of whom underwent screw fixation and 9 of whom had button fixation. 3 patients with all-inside ACLR had sustained early repeat ruptures within 6 months after surgery and had to be excluded from the further analysis. With screw fixation, the tibial tunnel volume changed significantly more over time compared to all-inside button fixation, with a larger initial increase at 6 months (from postoperative 2.9 ± 0.2 to 3.3 ± 0.2 cm3 at 6 months versus 1.7 ± 0.1 to 1.9 ± 0.2 cm3) and a greater final decrease over 2-5 years postoperatively (from 3.1 ± 0.2 to 1.9 ± 0.2 cm3 versus 1.8 ± 0.2 ± 0.1 to 1.3 ± 0.1 cm3) (P < 0.001). The femoral tunnel volume remained comparable between the two groups throughout the follow-up period, with an initial 1.6 ± 0.1 cm3 in both groups and 1.2 ± 0.1 vs. 1.3 ± 0.1 after 5 years in the screw and button groups, respectively (P ≥ 0.314). The maximum tibial and femoral tunnel diameters were significantly larger with screw fixation at all four time points. Tibial diameters measured 11.1 ± 0.2, 12.3 ± 0.3, 12.3 ± 0.4, and 11.2 ± 0.4 mm in the screw group versus 8.1 ± 0.3, 8.9 ± 0.3, 9.1 ± 0.4 and 8.2 ± 0.5 mm in the button group (P < 0.001). Femoral diameters measured 8.6 ± 0.2, 10.5 ± 0.4, 10.2 ± 0.3, and 8.9 ± 0.3 versus 7.3 ± 0.3, 8.4 ± 0.4, 8.4 ± 0.3, 7.5 ± 0.3, respectively (P ≤ 0.007). Four patients (33%) in the screw group exceeded a diameter of 12 mm on the tibial side after 5 years versus none in the button group (not significant, P = 0.104). Tibial anteroposterior translation measurement with KT-1000 after 5 years was 2.3 ± 2.4 mm in the screw group versus 3.2 ± 3.5 mm in the button group (not significant, P = 0.602). There were no significant differences between the groups in any of the other clinical outcomes.

CONCLUSION

Tibial tunnels in ACLR with screw fixation were associated with a larger increase in tunnel volume within the first 2 years and a greater decrease up to 5 years after surgery, while femoral tunnel volumes did not differ significantly. On the tibial side, the need for staged revision ACLR may be greater after biodegradable interference screw fixation if repeat ruptures occur, especially within the first 2 years after primary ACLR. Concerns may remain regarding a higher graft failure rate with all-inside ACLR.

LEVEL OF EVIDENCE

II.

RCT CONSORT

NCT01755819.

Histopathological Analysis of the Degree of Tendinosis in Failed Anterior Cruciate Ligament Grafts

INTRODUCTION

After reconstruction of the anterior cruciate ligament, the modification processes in the transplanted tendon tissue directly influence the biomechanical properties of the knee. The histopathological alterations in failed grafts have hardly been studied.

OBJECTIVE

Our study focused on examining the presence and extent of tendinosis (low or high grade) in the tendon tissue of failed anterior cruciate ligament reconstructions. We considered its relationship to the type of transplant, the symptoms, the arthroscopic appearance, the mode of trauma, and the timing of the failure.

MATERIALS AND METHODS

The tendon tissue of failed anterior cruciate ligament reconstructions in 30 patients was gathered during revision surgery and its histopathology was analysed for the occurrence of structural alterations. The classification of the tendinosis as low or high grade was semiquantitative based on five qualities. We used a standardised questionnaire to collect patient data and we used the Marburg Arthroscopy Score for the intraoperative evaluation of the graft.

RESULTS

We found histological vitality and, except for two samples, structural alterations consistent with tendinosis, predominantly high grade, in all failed anterior cruciate ligament grafts. No direct link could be proved between the degree of tendinosis and the type of graft used, the symptoms (except for instability) or the timing of the graft failure, the mode of trauma, or the arthroscopic appearance of the failed plasty. However, the accumulation of high-grade tendinosis in patients with hamstring tendons, subjective instability, and graft failure between 1 to 5 years postoperatively was noteworthy.

CONCLUSION

Structural alterations consistent with tendinosis could be detected, with different expressions, in the vital tendon tissue of anterior cruciate ligament reconstructions. This indicates that the graft is subject to repetitive microtrauma. However, it is still unclear how tendinosis influences the failure of anterior cruciate ligament reconstructions.

Hierarchical helical carbon nanotube fibre as a bone-integrating anterior cruciate ligament replacement

High rates of ligament damage require replacements; however, current synthetic materials have issues with bone integration leading to implant failure. Here we introduce an artificial ligament that has the required mechanical properties and can integrate with the host bone and restore movement in animals. The ligament is assembled from aligned carbon nanotubes formed into hierarchical helical fibres bearing nanometre and micrometre channels. Osseointegration of the artificial ligament is observed in an anterior cruciate ligament replacement model where clinical polymer controls showed bone resorption. A higher pull-out force is found after a 13-week implantation in rabbit and ovine models, and animals can run and jump normally. The long-term safety of the artificial ligament is demonstrated, and the pathways involved in integration are studied.

Good Short-Term Clinical Outcomes and Low Rates of Return to Sports after Repeat Revision ACL Reconstruction

Repeat revision anterior cruciate ligament reconstruction (ACL-R) is a rare, demanding procedure and, as such, has not been well studied. Most of the available literature shows improved functional outcomes compared with preoperative state but inferior results when compared with primary ACL-R, particularly regarding return to preinjury level of sports. The purpose of this study was to assess functional outcomes in patients who had undergone repeat revision ACL-R. The secondary aims were to register return to sports, associated meniscal and/or chondral lesions, and evaluate radiological anatomical parameters. Nine patients between 2011 and 2017 were evaluated, who had a minimum follow-up of 2 years. Median age at repeat ACL-R was 32 years (interquartile range [IQR], 30-34 years) and the median follow-up was 27 months (IQR, 24-39 months). Data collected prior to surgery and at last follow-up included patient demographics, operative findings, physical examination findings including pivot shift and KT-1000 arthrometer measurement; Lysholm and International Knee Documentation Committee (IKDC) subjective scores; and return to sports and level using the Tegner score. Knee Injury and Osteoarthritis Outcome Score (KOOS) subjective score and radiographic anatomical parameters were recorded at last follow-up. Mean IKDC and Lysholm score improvement was 25 points (confidence interval [CI] 12-37) and 25 points (CI 11-39), respectively (p < 0.001). The median postoperative KOOS score was pain: 93 (IQR, 64-96); symptoms: 94 (IQR, 83-97); activities of daily life: 96 (IQR, 90-100); sports: 75 (IQR, 50-90); and quality of life: 50 (IQR, 43-81). Postoperative median side-to-side KT-1000 arthrometer difference was 2 mm (IQR, 1-8 mm). The median radiographic posterior tibial slope was 10 degrees (IQR, 9-10). One patient was considered a failure at 16 months postoperative. Only 44% (four out of nine) patients were able to return to their sports. None of these patients had a cartilage injury, while three out of five patients who did not return to their sports had International Cartilage Regeneration & Joint Preservation Society grade III or IV cartilage injury. Patients should be counseled on the challenging outcomes of repeat revision ACL-R. This is Level IV, therapeutic case series.

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

PURPOSE

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

METHODS

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

RESULTS

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

CONCLUSION

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

LEVEL OF EVIDENCE

Retrospective study-III.

Equivalent outcomes of ACL revision with over-the-top single and double-bundle reconstruction using hamstring tendon compared to anatomical single and double-bundle reconstruction

Purpose

In revision anterior cruciate ligament reconstruction (ACLR), our procedure of choice is the over-the-top route (OTTR) for cases where it is difficult to use a primary bone tunnel or to create a new bone tunnel due to the enlargement or malposition of the bone tunnel. Depending on the condition of the primary bone tunnel, we choose single (bone tunnel or OTTR) or double (bone tunnel or anteromedial (AM) bundle: OTTR /posterolateral (PL) bundle: bone tunnel) for femoral fixation. This study showed the results of single and double OTTR revision ACLR using the hamstring tendon.

Methods

Seventy-eight patients, who underwent revision ACLR using the hamstring tendon and who could be followed up for more than 2 year, were included in this study. The methods of revision ACLR were single in 54 cases (bone tunnel: 24 cases; OTTR method: 30 cases) and double in 24 cases (bone tunnel: 16 cases; OTTR for AM bundle and bone tunnel for PL bundle: eight cases). The cause of re-injury, the meniscus and cartilage injury, the reconstruction method, and the Lysholm score, Lachman test, Pivot-shift test, and the side-to-side difference in the tibial anterior translation were evaluated before and after surgery.

Results

There was no statistically significant difference in the Lyshom score, Lachman / Pivotshift test and side-to-side difference anterior translation of the tibia between the four groups.

Conclusions

The clinical results of single and double OTTR revision ACLR are equivalent to those of anatomic single and double bone tunnel procedures.

Remnants-preserving ACL reconstruction using direct tendinous graft fixation: a new rat model

BACKGROUND

Anterior cruciate ligament (ACL) repair techniques are new emerging strategies prevailing, in selected cases, over standard reconstruction of the ACL with excision of its remnants. Mid-substance ACL tears represent a challenge for ACL repair techniques, and remnants-preserving ACL reconstruction (rp-ACLR) using an autograft remains the recommended treatment in this situation. However, morbidity associated with the autograft harvesting prompts the need for alternative surgical strategies based on the use of synthetic scaffolds. Relevant small animal models of mid-substance tears with ACL remnants preservation and reconstruction are necessary to establish the preliminary proof of concept of these new strategies.

METHODS

A rat model of rp-ACLR using a tendinous autograft after complete mid-substance ACL transection was established. Twelve weeks following surgery, clinical outcomes and knee joints were assessed through visual gait analysis, Lachman tests, thigh perimeter measurements, magnetic resonance imaging, micro-computed tomography, and histology, to evaluate the morbidity of the procedure, accuracy of bone tunnel positioning, ACL remnants fate, osteoarthritis, and autograft bony integration. Results were compared with those obtained with isolated ACL transection without reconstruction and to right non-operated knees.

RESULTS AND DISCUSSION

Most operated animals were weight-bearing the day following surgery, and no adverse inflammatory reaction has been observed for the whole duration of the study. Autograft fixation with cortical screws provided effective graft anchorage until sacrifice. Healing of the transected ACL was not observed in the animals in which no graft reconstruction was performed. rp-ACLR was associated with a reduced degeneration of the ACL remnants (p = 0.004) and cartilages (p = 0.0437). Joint effusion and synovitis were significantly lower in the reconstructed group compared to the transected ACL group (p = 0.004). Most of the bone tunnel apertures were anatomically positioned in the coronal and/or sagittal plane. The most deviated bone tunnel apertures were the tibial ones, located in median less than 1 mm posteriorly to anatomical ACL footprint center.

CONCLUSION

This study presents a cost-effective, new relevant and objective rat model associated with low morbidity for the preliminary study of bio-implantable materials designed for remnants-preserving ACL surgery after mid-substance ACL tear.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction with Cannulated Allograft Bone Dowels Soaked in Bone Marrow Aspirate Concentrate

Anterior cruciate ligament reconstruction (ACLR) is one of the most common orthopedic procedures performed each year. The majority of patients undergoing these reconstructions will experience long-term stability and symptomatic relief; however, some will require a revision ACLR procedure. In general, revision ACLRs are more challenging than primary ACLRs due to several diagnostic and technical considerations. A revision ACLR can be performed with either a one-stage or two-stage procedure, which is based on the presence or absence of malpositioned tunnels, bone loss, and tunnel expansion. Recently, the introduction of preshaped allograft bone dowels as a bone grafting option has gained popularity. They provide immediate structural stability and avoid donor site morbidity associated with autografts. The purpose of this article is to outline a bone-grafting tunnel technique with cannulated allograft bone dowels soaked in bone marrow aspirate concentrate (BMAC) used in the first stage of a staged revision ACLR procedure.

Revision Anterior Cruciate Ligament Reconstruction with the All-Soft Tissue Quadriceps Tendon Autograft Has Acceptable Early and Intermediate-Term Outcomes

PURPOSE

The purposes were to (1) examine early to intermediate-term clinical outcomes and complications of revision anterior cruciate ligament reconstruction (ACLR) using all-soft tissue quadriceps tendon (QT) autografts, and (2) compare quadriceps strength between patients who had hamstring versus patella tendon autografts in their previous reconstruction.

METHODS

One hundred patients (52 males/48 females; 22.6 ± 8.0 years) undergoing revision ACLR with all-soft tissue QT autografts were prospectively followed. All revision procedures were performed by a single surgeon, using a minimally invasive graft harvest technique and suspensory fixation. Subjective assessment of knee function was obtained before and after surgery with the International Knee Documentation Committee (IKDC) survey. Postoperative knee laxity and isokinetic quadriceps strength were collected at regular intervals. Strength was reported as limb symmetry index (LSI; surgical side divided by nonsurgical side). Complications including hematomas, postoperative loss of knee extension, and graft failures were recorded. To determine clinical significance (P ≤ .05), outcomes were compared using analysis of variance or paired samples t-tests.

RESULTS

The mean IKDC scores significantly improved (54.3 ± 13.0 vs 82.8 ± 13.8), with an average follow-up of 42.2 ± 21.2 months. There were no significant changes in knee laxity side-to-side differences: 6 weeks (1.2 ± 1.5 mm), 3 months (1.2 ± 1.8 mm), 6 months (1.4 ± 1.6 mm). Quadriceps LSIs significantly improved from 71.6% ± 19.3% at 6 months to 81.5% ± 19.3% at 12 months for 60°/s isokinetic testing and 76.6% ± 16.4% at 6 months to 83.9% ± 16.9% at 12 months for 180°/s testing. Graft harvest site hematomas developed in 2 patients, postoperative loss of knee extension in 4 patients, and graft failure in 11 patients. No significant differences in quadriceps or hamstrings LSIs were noted between patients with previous hamstring versus patella tendon autografts (P > .050).

CONCLUSION

Revision ACLR with all-soft tissue QT autografts has acceptable early and intermediate-term outcomes with reasonable complication rates (11/80 patients with follow-up). Secondary insult to the extensor mechanism via QT autograft harvest does not adversely affect strength after prior patellar tendon versus hamstring autograft.

LEVEL OF EVIDENCE

Level IV, cases series subgroup analysis.

Multiple ACL Revision: Failure Analysis and Clinical Outcomes

Anterior cruciate ligament (ACL) reconstruction represents one of the most successful orthopedic surgical procedures. Nevertheless, ACL revisions are still very frequent, with a small but relevant number of failures. The purpose of this study is to analyze the failure causes and the clinical outcomes of patients who underwent a re-revision ACL reconstruction. Between January 2009 and December 2017, 263 ACL revisions were performed by a single senior surgeon. Seventeen patients (12 males and 5 females) underwent re-revision ACL reconstruction meeting the inclusion criteria. The mean age was 28.4 years (range, 19-41 years). Before the re-revision, the patients were evaluated preoperatively and after a mean follow-up of 29 months (range, 13-58 months). Assessment included subjective and objective evaluations (Lysholm and International Knee Documentation Committee [IKDC]), KT-2000 arthrometer, radiographic study, and preoperative computed tomography scan. Five patients showed a too anterior previous femoral tunnel and seven a too vertical and posterior tibial tunnel; eight meniscal tears were found. Five patients had grade III-IV according to Outerbridge cartilage lesions. IKDC showed a statistically significant improvement (A + B 35%, C + D 65% preop, A + B 82%, C + D 18% postop, odds ratio: 0.1169; p = 0.0083). The mean Lysholm score ranged from 43 ± 9 to 87 ± 7 (p < 0.001). The KT-2000 arthrometer showed a statistically significant improvement from a mean of 5.8 ± 1.4 to 1.5 ± 1.1 (p < 0.001) at last follow-up. Out of 17 patients, only 4 returned to sports activity at the same preinjury levels. Postoperatively at the last follow-up after last revision surgery, no osteoarthritis evolution was observed. This study showed good clinical and radiological results after the last revision ACL surgery in patients with multiple failures of ACL reconstruction but only one-fourth of the patients returned to the same preoperative sport level. Traumatic events, technical errors, and untreated peripheral lesions are the main causes of multiple previous failures; the worst clinical outcomes were found in the patients with high grade of chondral lesions.

Allograft Bone Dowels Show Better Incorporation in Femoral Versus Tibial Tunnels in 2-Stage Revision Anterior Cruciate Ligament Reconstruction: A Computed Tomography-Based Analysis

PURPOSE

The purpose of this study was to quantitatively evaluate the radiographic outcomes of allograft dowels used in 2-stage revision anterior cruciate ligament reconstruction (ACLR) and to compare the incorporation rates of dowels placed in tibial and femoral tunnels.

METHODS

Prospective review of patients who underwent 2-stage revision ACLR with allograft bone dowels. Inclusion criteria were tibial/femoral tunnel diameter of ≥14 mm on preoperative computed tomography (CT) or overlapping of prior tunnels with planned tunnels. Second-stage timing was determined based on qualitative dowel integration on CT obtained at ∼3 months after the first stage. Quantitative analysis of incorporation rates was performed with the union ratio (UR) and occupying ratio (OR) on postoperative CT scans.

RESULTS

Twenty-one patients, with a mean (SD) age of 32.1 (11.4; range, 18-50) years, were included. Second-stage procedures were performed at a mean (SD) of 6.5 (2.1; range, 2.4-11.5) months after first-stage revision. All dowels showed no signs of degradation at the host bone/graft junction at the second-stage procedure. The mean (SD) diameter of the dowels placed in tibial tunnels was greater than those placed in femoral tunnels (16.1 [2.3] mm vs 12.4 [1.6] mm; P < .05). CT was obtained at a mean (SD) of 121 (28; range, 59-192) days after the first-stage surgery. There was no difference between the OR of femoral and tibial tunnels (mean [SD], 87.6% [4.8%] vs 85.7% [10.1%]; P = .484), but the UR was significantly higher in femoral tunnels (mean [SD], 83% [6.2%] vs 74% [10.5%], P = .005). The intraclass correlation coefficients of OR and UR measurements indicated good reliability.

CONCLUSIONS

Allograft bone dowels are a viable graft choice to replenish bone stock in the setting of a staged revision ACL reconstruction. Allograft dowels placed in femoral tunnels had a higher healing union ratio than tibial tunnel allografts and no evidence of degradation at the bone/graft junction, with no difference seen in occupying ratio.

LEVEL OF EVIDENCE

Level IV, case series.

High variability in anterior cruciate ligament femoral footprint: Implications for anatomical anterior cruciate ligament reconstruction

BACKGROUND

The study aimed to (1) investigate the variability of the femoral ACL center in ACL-ruptured patients, (2) identify whether the currently available over-the-top femoral ACL guides could allow for anatomical reconstruction of the native ACL footprint.

MATERIAL AND METHODS

Magnetic resonance images of 95 knees with an ACL rupture were used to create three-dimensional models of the femur. The femoral ACL footprint area was outlined on each model, and the location of the femoral ACL center was reported using an anatomical coordinate system. The distance of the femoral ACL center from the over-the-top position was measured.

RESULTS

The femoral ACL center demonstrated a high intersubject variability ranging from 1.8 mm (9%) to 12.3 mm (60%) posterior and from 7.7 mm (37%) distal to 4.8 mm (23%) proximal using the posterior condyle circle reference. The average distance of the femoral ACL center from the over-the-top position was 1.9 ± 1.5 mm posterior and 13.8 ± 2.7 mm distal, respectively. The contemporary over-the-top femoral ACL aimers could restore the femoral ACL center in only 6.5% of the patients.

CONCLUSIONS

The femoral ACL center demonstrated a high variation on its location, which resulted in a high intersubject variability from the over-the-top position. The contemporary over-the-top femoral tunnel guides do not provide sufficient offset to allow for an anatomical ACL reconstruction. Anteromedial-portal specific femoral ACL guides with a femoral offset ranging from 10 to 18 mm in the proximal/distal direction are required to restore the native ACL footprint.

Adjustable suspension versus hybrid fixation in hamstring autograft anterior cruciate ligament reconstruction

BACKGROUND

There has been increased use of adjustable suspensory fixation (ASF) for anterior cruciate ligament reconstruction (ACLR). Potential benefits are the ability to use a shorter graft and to prevent graft displacement and damage. The purpose of this study was to establish the efficacy of this fixation method and assess whether it leads to less tunnel widening, and avoids known complications of screw fixation.

METHODS

Thirty-eight patients who underwent ACLR with ASF on both the femoral and tibial sides met the inclusion criteria and were propensity matched demographically with 38 patients who underwent hybrid fixation with femoral suspensory and tibial screw and sheath. At one-year, KT-1000 knee laxity measurements were recorded and detailed MRI analysis looking at tunnel aperture widening, tunnel appearance, graft integration within the tunnels, and graft healing.

RESULTS

MRI comparison between ASF and hybrid cohorts revealed no significant differences in graft signal or integration, and clinically there were no differences in knee laxity between cohorts (mean 1.5 mm ± 2.0 and 1.5 mm ± 2.3 (n.s.) in the ASF and hybrid fixation respectively). Significantly less aperture tibial tunnel widening (2.2 mm versus 4.4 mm, p < 0.0001) and tibial cysts (2 versus 9, p = 0.047) were observed in the ASF cohort, whilst mean femoral tunnel widening was comparable between both cohorts (ASF 2.8 mm, hybrid 3.2 mm; n.s.).

CONCLUSIONS

Hamstring autografts for ACLR fixed using either ASF or a hybrid fixation technique provided comparable knee stability and MRI graft signal intensity. Tibial ASF demonstrated significantly less tibial aperture widening and tunnel cyst formation when compared to screw and sheath fixation.

Does Revision Anterior Cruciate Ligament (ACL) Reconstruction Provide Similar Clinical Outcomes to Primary ACL Reconstruction? A Systematic Review and Meta-Analysis

More revisionary reconstruction procedures are required following failing anterior cruciate ligament (ACL) reconstructions, which are often regarded as a technique challenge with very limited goals. This study will be performed to compare the outcomes between groups of primary and revision knee reconstruction. Two observers conducted the literature retrieval from the platforms of PubMed, Embase, and CENTRAL. Studies which compared knee function and stability between primary and revisionary reconstructions were included. The data was synthesized by meta‐analysis with fixed‐ or random‐effects models as appropriate. A total of 10 eligible studies were included with 954 subjects in the primary group and 378 in the revision group. The International Knee Documentation Committee International Knee Documentation Committee (IKDC) subscores, side‐to‐side difference, and Lysholm score were demonstrated to be significantly improved at final follow‐up in both groups, while Tegner score was not. The overall IKDC, Knee injury and Osteoarthritis Outcome Score (KOOS), and Lysholm scores were significantly inferior in the revision group compared to the primary group. However, knee laxity according to side‐to‐side difference was demonstrated to be similar between the two groups. Revision ACL reconstruction (RACLR) could provide patients with excellent restoration of knee outcomes compared to the status before revision. Also, while knee function in the revision group was inferior to the primary group, knee stability was equivalent between the two groups at the final follow‐up.

ACL reconstruction with adjustable-length loop cortical button fixation results in less tibial tunnel widening compared with interference screw fixation

PURPOSE

To compare tunnel widening and clinical outcome after anterior cruciate ligament reconstruction (ACLR) with interference screw fixation and all-inside reconstruction using button fixation.

METHODS

Tunnel widening was assessed using tunnel volume and diameter measurements on computed tomography (CT) scans after surgery and 6 months and 2 years later, and compared between the two groups. The clinical outcome was assessed after 2 years with instrumented tibial anteroposterior translation measurements, hop testing and International Knee Documentation Committee (IKDC), Lysholm and Tegner activity scores.

RESULTS

The study population at the final follow-up was 14 patients with screw fixation and 16 patients with button fixation. Tibial tunnels with screw fixation showed significantly larger increase in tunnel volume over time (P = 0.021) and larger tunnel diameters after 2 years in comparison with button fixation (P < 0.001). There were no significant differences in femoral tunnel volume changes over time or in tunnel diameters after 2 years. No significant differences were found in the clinical outcome scores.

CONCLUSIONS

All-inside ACLR using button fixation was associated with less tibial tunnel widening and smaller tunnels after 2 years in comparison with ACLR using screw fixation. The need for staged revision ACLRs may be greater with interference screws in comparison with button fixation at the tibial tunnel. The clinical outcomes in the two groups were comparable.

LEVEL OF EVIDENCE

II. RCT: Consort NCT01755819.

ACL hamstring grafts fixed using adjustable cortical suspension in both the femur and tibia demonstrate healing and integration on MRI at one year

PURPOSE

To present the clinical outcomes and magnetic resonance imaging (MRI) analysis of adjustable cortical suspensory fixation for the femur and tibia in hamstring autograft anterior cruciate ligament reconstruction.

METHODS

A cohort of 233 sequential patients was analysed for graft failure rate and subjective IKDC, Tegner and Lysholm scores. 144 validated 1-year MRIs assessed and correlated graft healing and tunnel widening.

RESULTS

At mean follow-up of 28 months ± 8.2 [median 26, range 12-49], the graft failure rate was 4.7%. Significant improvements were seen in all clinical scores (p < 0.001). MRI analysis showed 71% with fully integrated grafts in the tibia and 24% in the femur, with the remainder all showing greater than 50% integration. Graft signal was low and homogenous in 67% in the tibia, 29% in the intra-articular portion and 20% in the femur. One patient had greater than 50% high signal in the tibial graft and one in the intra-articular graft, all others demonstrated greater than 50% low signal. Both graft integration and signal were significantly better in the tibia than the femur (p < 0.01). Tunnel widening was 2.2 ± 1.4 mm and 2.7 ± 1.3 mm in the tibia and femur, respectively. Comparison of individual MRI appearances and overall clinical outcome at the same 12-month point demonstrated no consistent significant correlation.

CONCLUSION

Adjustable cortical suspensory fixation in both femoral and tibial tunnels provides good clinical outcomes and a low graft rupture rate. Grafts demonstrate healing with comparatively low tunnel widening. There was no consistent significant correlation between the appearances on MRI and clinical outcome.

LEVEL OF EVIDENCE

Case-control study, Level III.

Single-Stage Revision Anterior Cruciate Ligament Reconstruction Using Fast-Setting Bone Graft Substitutes

Revision anterior cruciate ligament reconstructions can be performed using either a single-stage or 2-stage technique. There are several benefits to using a single-stage approach when technically possible. Although not always feasible, eliminating the necessity of a 2-stage approach for certain indications is clearly preferable because it requires fewer operative procedures, leads to a more rapid recovery, and is cost effective. Here, we describe the use of fast-setting bone graft substitutes in the setting of single-stage revision anterior cruciate ligament reconstruction. The authors have found this technique useful in converting what would sometimes otherwise be approached using 2 stages into a single-stage procedure.

Single-stage revision anterior cruciate ligament reconstruction using bone grafting for posterior or widening tibial tunnels restores stability of the knee and improves clinical outcomes

PURPOSE

Revision ACL surgery may be complicated by tunnel malposition and/or tunnel widening and often requires a staged treatment approach that includes bone grafting, a period of several months to allow bone graft incorporation and then definitive revision ACL reconstruction. The purpose of this study was to evaluate the results of a single-staged ACL revision reconstruction technique using a cylindrical dowel bone graft for patients who have existing posteriorly placed and/or widened tibial tunnels in the tibia at a minimum of 2 years follow-up.

METHODS

Between 2010 and 2014, patients undergoing single-stage revision ACL reconstruction with the described technique were prospectively enrolled and evaluated. At a minimum of 24 months, patients were evaluated by physical examination, multiple clinical outcome instruments including KOOS, Tegner and Lysholm, and preoperative and postoperative MRIs.

RESULTS

At a mean of 35.1 months, 18 consecutive patients had no revision surgery and no subjective knee instability. There were statistically significant improvements in the Tegner (median 2, interquartile range 2.25; p < 0.01), Lysholm (20.0 ± 15.0; p < 0.01), KOOS symptoms scale (12.9 ± 11.8; p < 0.01), KOOS pain scale (15.4 ± 18.7; p < 0.01), KOOS ADL scale (13.5 ± 19.0; p < 0.01), KOOS sports scale (32.8 ± 26.4; p < 0.01), and KOOS QoL scale (18.1 ± 16.9; p < 0.01). Postoperative MRI demonstrated statistically significant anteriorization of the tibial tunnel and a statistically significant decrease in tunnel widening.

CONCLUSION

Revision ACL reconstruction utilizing a single-staged tibial tunnel grafting technique resulted in improved knee pain, function, and stability at a minimum of 24-month follow-up.

LEVEL OF EVIDENCE

IV.

Two-stage revision anterior cruciate ligament reconstruction

With the rising number of anterior cruciate ligament (ACL) reconstructions, revision ACL reconstructions are becoming increasingly common. A revision procedure may be performed to improved knee function, correct instability, and facilitate a return to normal activities. When performing a revision reconstruction, the surgeon decides between a single-stage or a two-stage revision. Two-stage revisions are rarely performed, but are particularly useful when addressing substantial tunnel-widening, active infection, and concomitant knee pathology (e.g., malalignment, other ligamentous injuries, meniscal or chondral lesions). Among these potential scenarios requiring a two-stage revision, tunnel-widening is the most common cause; the first stage involves graft removal, tunnel curettage, and bone grafting, followed by revision ACL reconstruction in the second stage. The purpose of this article is to review the preoperative planning, surgical considerations, rehabilitation, and outcomes of two-stage revision ACL reconstructions and summarize the recent literature outlining treatment results.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction Using Allograft Bone Dowels

Revision anterior cruciate ligament (ACL) reconstruction is substantially more challenging than primary reconstruction. Management of previously malpositioned or widened tunnels often requires innovative approaches for managing bony defects. Massive osteolysis with poor bone stock and convergence or overlapping of revision tunnels into the previously placed tunnels may necessitate a staged revision procedure. In this surgical technique description, we describe a method for the management of bony deficiencies using allograft bone dowels in staged revision ACL reconstruction.

Influence of tibial hybrid fixation on graft tension and stability in ACL double-bundle reconstruction

PURPOSE

Initial graft tension in anterior cruciate ligament (ACL) reconstruction affects stability and tension loss at follow-up. This study investigated the influence of hybrid tibial fixation in 3-tunnel double-bundle ACL reconstruction on initial graft tension and tension change and stability under anterior and combined rotatory loads.

METHODS

Eleven fresh-frozen cadaveric knees were reconstructed with an ACL double bundle using a 3-tunnel technique. Grafts were tightened to 80 N in 60° (AM bundle) and 15° (PL bundle) of flexion. Anterior tibial translation under 134 N of anterior shear load and translation under combined rotatory and valgus loads (10 Nm valgus stress, 4 Nm internal tibial torque) were determined at 0°, 30°, 60°, and 90° flexion. In addition, graft tension under continuous passive motion was determined. Intact, ACL-resected and ACL-reconstructed joints with either tibial extracortical graft fixation or extracortical plus supplemental aperture graft fixation (hybrid fixation) were tested.

RESULTS

Hybrid fixation did not increase graft tension in either bundle during fixation or in motion without additional load. AM-bundle tension increased (p < 0.05) at 0° under combined rotatory and valgus loads and at 30° and 60° under both loading conditions without decreasing the anterior tibial translation. PL-bundle tension increased (p < 0.05) only at 90° under combined rotatory and valgus loads.

CONCLUSIONS

Tibial hybrid fixation in 3-tunnel double-bundle ACL reconstruction increases time-zero AM- and PL-bundle tensions under loading conditions, generating greater construct stiffness. This could lead to a longer preservation of ACL-graft stability in clinical follow-up before bony incorporation.

Ectopic tissue engineered ligament with silk collagen scaffold for ACL regeneration: A preliminary study

Anterior cruciate ligament (ACL) reconstruction remains a formidable clinical challenge because of the lack of vascularization and adequate cell numbers in the joint cavity. In this study, we developed a novel strategy to mimic the early stage of repair in vivo, which recapitulated extra-articular inflammatory response to facilitate the early ingrowth of blood vessels and cells. A vascularized ectopic tissue engineered ligament (ETEL) with silk collagen scaffold was developed and then transferred to reconstruct the ACL in rabbits without interruption of perfusion. At 2weeks after ACL reconstruction, more well-perfused cells and vessels were found in the regenerated ACL with ETEL, which decreased dramatically at the 4 and 12week time points with collagen deposition and maturation. ACL treated with ETEL exhibited more mature ligament structure and enhanced ligament-bone healing post-reconstructive surgery at 4 and 12weeks, as compared with the control group. In addition, the ETEL group was demonstrated to have higher modulus and stiffness than the control group significantly at 12weeks post-reconstructive surgery. In conclusion, our results demonstrated that the ETEL can provide sufficient vascularity and cellularity during the early stages of healing, and subsequently promote ACL regeneration and ligament-bone healing, suggesting its clinic use as a promising therapeutic modality.

STATEMENT OF SIGNIFICANCE

Early inflammatory cell infiltration, tissue and vessels ingrowth were significantly higher in the extra-articular implanted scaffolds than theses in the joint cavity. By mimicking the early stages of wound repair, which provided extra-articular inflammatory stimulation to facilitate the early ingrowth of blood vessels and cells, a vascularized ectopic tissue engineered ligament (ETEL) with silk collagen scaffold was constructed by subcutaneous implantation for 2weeks. The fully vascularized TE ligament was then transferred to rebuild ACL without blood perfusion interruption, and was demonstrated to exhibit improved ACL regeneration, bone tunnel healing and mechanical properties.

The long-term clinical and radiological outcomes in patients who suffer recurrent injuries to the anterior cruciate ligament after reconstruction

Aims

The aim of this study was to investigate the long-term clinical and radiological outcome of patients who suffer recurrent injuries to the anterior cruciate ligament (ACL) after reconstruction and require revision surgery.

Patients and Methods

From a consecutive series of 200 patients who underwent primary reconstruction following rupture of the ACL, we identified 36 who sustained a further rupture, 29 of whom underwent revision surgery. Patients were reviewed prospectively at one, two, seven, 15 and about 20 years after their original surgery. Primary outcome measures were the number of further ruptures, the posterior tibial slope (PTS), and functional and radiological outcomes. These were compared with a gender and age matched cohort of patients who underwent primary ACL reconstruction only.

Results

At a mean follow-up of 18.3 years (14.3 to 20.2), 29 patients had undergone revision surgery and within this revision group 11 had sustained more than three ruptures of the ACL (3 to 6). The mean age at the time of revision reconstruction was 26.4 years (14 to 54). The mean PTS was significantly higher in those patients who suffered a further injury to the ACL (11°) compared with the control group (9°) (p < 0.001). The mean PTS in those patients who sustained more than three ruptures was 12°.

Conclusion

Patients who suffer recurrent injuries to the ACL after reconstruction have poorer functional and radiological outcomes than those who suffer a single injury. The causes of further injury are likely to be multifactorial but an increased PTS appears to have a significant association with recurrent ACL injuries. Cite this article: Bone Joint J 2017;99-B:337–43.

Anterior cruciate ligament reconstruction tunnel size: causes of tunnel enlargement and implications for single versus two-stage revision reconstruction

Anterior cruciate ligament (ACL) reconstructions have increased over the past 25 years. The increased incidence of ACL reconstructions has translated into a larger number of graft failures and revision ACL procedures. It is important to understand the causes of graft failure when evaluating for a revision ACL reconstruction and to appreciate changes in tunnel anatomy over time prior to planning revision surgery. In this manuscript, tunnel size for ACL reconstruction and implications for single-stage versus two-stage revision ACL reconstruction will be discussed, as well as causes of tunnel enlargement, including mechanical and biological factors.

One stage revision single-bundle anterior cruciate ligament reconstruction with impacted morselized bone graft following a failed double-bundle reconstruction

Although double-bundle anterior cruciate ligament (ACL) reconstruction has theoretical benefits such as more accurate reproduction of ACL anatomy, it is technically more demanding surgery. This report describes the case of a one stage revision single-bundle ACL reconstruction after primary double-bundle ACL reconstruction. A professional dancer had an ACL previously reconstructed with a double-bundle technique, but the femoral tunnels were malpositioned resulting in residual laxity and rotational instability. The previous femoral tunnel positions were vertical and widened. The previous vertical tunnels were filled with impacted bone graft and a revision single-bundle ACL reconstruction was performed via the new femoral tunnel with a 2 O'clock position between the previous two tunnels. After 10 months of postoperative rehabilitation, the patient returned to professional dancing with sound bony union and without any residual instability.

Revision Anterior Cruciate Ligament Reconstruction: Results of a Single-stage Approach Using Allograft Dowel Bone Grafting for Femoral Defects

INTRODUCTION

The purpose of this study was to present results of single-stage revision anterior cruciate ligament (ACL) reconstruction using an allograft bone dowel for isolated femoral bony deficiency.

METHODS

Sixteen patients underwent single-stage revision ACL reconstruction using an allograft bone dowel for isolated femoral bony deficiency between 2007 and 2012. Twelve patients (75%) completed study visits, which included CT scans as well as completion of validated outcomes measures.

RESULTS

The average KT-1000 side-to-side difference was 1.0 mm ± 2.9 mm. The average International Knee Documentation Committee score was 70.2 ± 17.8, the Tegner score was 4.8 ± 2.8, and the visual analog scale pain score was 2.8 ± 2.4. An analysis of CT scans showed that all 12 dowels had excellent (>75%) incorporation.

CONCLUSIONS

A single-stage approach for revision ACL reconstruction using allograft dowels for isolated femoral bony deficiency yields objective and subjective outcomes comparable to those reported in the literature for two-stage and other single-stage techniques, with good incorporation of the dowels.

LEVEL OF EVIDENCE

Retrospective case series, level IV.

LARS Artificial Ligament Versus ABC Purely Polyester Ligament for Anterior Cruciate Ligament Reconstruction

Background:

Graft choice for anterior cruciate ligament (ACL) reconstruction is of critical importance. Various grafts have been used so far, with autografts long considered the optimal solution for the treatment of ACL-deficient knees. Limited data are available on the long-term survivorship of synthetic grafts.

Purpose:

To compare the functional outcome and survivorship of ACL reconstructions performed using the LARS (ligament augmentation and reconstruction system) ligament and the ABC (active biosynthetic composite) purely polyester ligament.

Study Design:

Case series; Level of evidence, 4.

Methods:

The results of 72 patients who underwent primary arthroscopic ACL reconstruction with the LARS ligament and 31 cases with an ABC purely polyester ligament were reviewed. The mean follow-up periods for the LARS and ABC groups were 9.5 and 5.1 years, respectively. A survivorship analysis of the 2 synthetic grafts was performed using the Kaplan-Meier method with a log-rank test (Mantel-Cox, 95% CI). Lysholm, Tegner activity, Knee injury and Osteoarthritis Outcome Score (KOOS), and International Knee Documentation Committee (IKDC) scores as well as laxity measurements obtained using a KT-1000 arthrometer were recorded for all intact grafts, and a Mann-Whitney U test was used for comparison reasons.

Results:

The rupture rates for LARS and ABC grafts were 31% (95% CI, 20%-42%) and 42% (95% CI, 25%-59%), respectively. For intact grafts, the mean Lysholm score was good for both groups (90 for the LARS group and 89 for the ABC group), with the majority of patients returning to their preinjury level of activities, and the mean IKDC score was 90 for the LARS group and 86 for the ABC group.

Conclusion:

The rupture rates of both LARS and ABC grafts were both high. However, the LARS ligament provided significantly better survivorship compared with the ABC ligament at short- to midterm follow-up (95% CI).

Anterior Cruciate Ligament: Structure, Injuries and Regenerative Treatments

Anterior cruciate ligament (ACL) is one of the most vulnerable ligaments of the knee. ACL impairment results in episodic instability, chondral and meniscal injury and early osteoarthritis. The poor self-healing capacity of ACL makes surgical treatment inevitable. Current ACL reconstructions include a substitution of torn ACL via biological grafts such as autograft, allograft. This review provides an insight of ACL structure, orientation and properties followed by comparing the performance of various constructs that have been used for ACL replacement. New approaches, undertaken to induce ACL regeneration and fabricate biomimetic scaffolds, are also discussed.

[Dynamic intraligamentary stabilization of the anterior cruciate ligament. Operative technique and short-term clinical results]

BACKGROUND

Reconstruction of tears in the anterior cruciate ligament with a tendon graft is the current gold standard.

OBJECTIVES

Dynamic intraligamentary stabilization is a new technique for preservation of the anterior cruciate ligament.

METHODS

This article describes the indications, operative technique, rehabilitation and preliminary results after dynamic intraligamentary stabilization for acute anterior cruciate ligament ruptures.

RESULTS

A total of 24 women and 31 men with an acute anterior cruciate ligament tear were included in a prospective clinical trial. Of the patients 26 had already been followed-up for 12 months and satisfying values for the Lysholm, Tegner and International Knee Documentation Committee (IKDC) outcome scores were achieved. High subjective patient satisfaction was also achieved. The Lachman test showed a mean anterior translation difference to the healthy side of 1.7 mm.

CONCLUSION

Dynamic intraligamentary stabilization in combination with microfracturing of the notch can provide biomechanical and biological conditions for self-healing of the anterior cruciate ligament. Further clinical and biomechanical research is needed to identify appropriate patients and rupture types suitable for this new technique.

Influence of Different Tibial Fixation Techniques on Initial Stability in Single-Stage Anterior Cruciate Ligament Revision With Confluent Tibial Tunnels: A Biomechanical Laboratory Study

PURPOSE

To kinematically and biomechanically compare 4 different types of tibial tunnel management in single-stage anterior cruciate ligament (ACL) revision reconstruction with the control: primary ACL reconstruction using a robotic-based knee testing setup.

METHODS

Porcine knees and flexor tendons were used. One hundred specimens were randomly assigned to 5 testing groups: (1) open tibial tunnel, (2) bone plug technique, (3) biodegradable interference screw, (4) dilatation technique, and (5) primary ACL reconstruction. A robotic/universal force-moment sensor testing system was used to simulate the KT-1000 (MEDmetric, San Diego, CA) and pivot-shift tests. Cyclic loading and load-to-failure testing were performed.

RESULTS

Anterior tibial translation increased significantly with all of the techniques compared with the intact ACL (P < .05). In the simulated KT-1000 test, groups 2 and 3 achieved results equal to those of primary ACL reconstruction (P > .05). The open tunnel and dilated tunnel techniques showed significantly greater anterior tibial translation (P < .05). The results of the simulated pivot-shift test were in accordance with those of the KT-1000 test. No significant differences could be observed regarding stiffness or maximum load to failure. However, elongation was significantly lower in the primary ACL reconstruction group compared with groups 1 and 3 (P = .02 and P = .03, respectively).

CONCLUSIONS

Filling an incomplete and incorrect tibial tunnel with a press-fit bone plug or a biodegradable interference screw in a standardized laboratory situation provided initial biomechanical properties and knee stability comparable with those of primary ACL reconstruction. In contrast, the dilatation technique or leaving the malplaced tunnel open did not restore knee kinematics adequately in this model. Backup extracortical fixation should be considered because the load to failure depends on the extracortical fixation when an undersized interference screw is used for aperture fixation.

CLINICAL RELEVANCE

Our biomechanical results could help orthopaedic surgeons to optimize the results of primary ACL revision with incomplete, incorrect tunnel placement.

The role of computer assisted navigation in revision surgery for failed anterior cruciate ligament reconstruction of the knee: A continuous series of 52 cases

INTRODUCTION

The causes of failure of anterior cruciate ligament (ACL) reconstruction mainly involve incorrect tunnel positioning. There is no intraoperative tool allowing the surgeon to test graft biomechanics and to confirm that the new graft is in an optimal position.

HYPOTHESIS

Control is improved with computer assisted navigation.

MATERIAL AND METHODS

In this retrospective study, revision ACL reconstruction was performed with a new autologous graft in a continuous series of 52 failed ACL reconstructions. A computer assisted navigation system was used intraoperatively in all knees. Evaluation with this system confirmed the position of old and new tunnels as well as intraoperative laxity.

RESULTS

Evaluation of tunnel position based on traditional radiological criteria found in the literature significantly underestimated graft biomechanics: 69% of the cases presented with unfavorable graft ansiometry (mean: 13 ± 2.2mm) while the correct position of the tibial tunnel was identified in 64% of cases on radiography and the femoral tunnel in 48%. All new grafts were optimally positioned by the computer assisted navigation system with a mean isometery of 3.2 (± 0.7) mm. Comparative pre- and postoperative evaluation of laxity showed a statistically significant improvement (P < 0.001): preoperative and postoperative Lachman test: 10.5 ± 2 mm and 3 ± 0.5, respectively; global rotational laxity: 24 ± 5° and 37 ± 7° respectively.

CONCLUSION

The use of a computer assisted navigation system allows optimal positioning of the graft as well as a predictive assessment of laxity.

The use of the ligament augmentation and reconstruction system (LARS) for posterior cruciate reconstruction

PURPOSE

To systematically review and assess the use of the Ligament Advanced Reinforcement System (LARS; Surgical Implants and Devices, Arc-sur-Tille, France) for posterior cruciate ligament (PCL) reconstruction.

METHODS

A search of multiple databases was conducted using the following terms: (LARS[All Fields] AND posterior[All Fields]) OR (LARS[All Fields] AND PCL[All Fields]). The methodologic quality of each article was assessed by use of abridged Downs and Black criteria.

RESULTS

Fifty-four studies were found from the database search, of which 5 were included in the final review (4 case series and 1 case-control study). One hundred twenty-nine PCL reconstructions with LARS were performed. The mean patient age was 32.2 years, with 89 male and 40 female patients included. The mean follow-up time ranged from 10.5 to 44 months. Lysholm scores improved from a mean of 64.8 preoperatively to 89.8 postoperatively. No patients had International Knee Documentation Committee grade 1 or 2 preoperatively, with 93.0% achieving this postoperatively. Only 1 case of synovitis and 1 case of graft rupture were reported.

CONCLUSIONS

There is little evidence on the effectiveness of PCL reconstructions using LARS ligaments. What data there are show great promise, with short- and medium-term outcome data appearing favorable to autograft reconstruction. Complication rates are encouragingly low.

CLINICAL RELEVANCE

LARS has great potential for PCL reconstruction. Further studies are needed regarding the use of LARS ligaments during PCL reconstruction, including longer follow-up periods and investigation into the optimal timing for reconstruction. This may be best achieved by way of a multicenter study.

Anterior cruciate ligament- specialized post-operative return-to-sports (ACL-SPORTS) training: a randomized control trial

Background

Anterior cruciate ligament reconstruction (ACLR) is standard practice for athletes that wish to return to high-level activities; however functional outcomes after ACLR are poor. Quadriceps strength weakness, abnormal movement patterns and below normal knee function is reported in the months and years after ACLR. Second ACL injuries are common with even worse outcomes than primary ACLR. Modifiable limb-to-limb asymmetries have been identified in individuals who re-injure after primary ACLR, suggesting a neuromuscular training program is needed to improve post-operative outcomes. Pre-operative perturbation training, a neuromuscular training program, has been successful at improving limb symmetry prior to surgery, though benefits are not lasting after surgery. Implementing perturbation training after surgery may be successful in addressing post-operative deficits that contribute to poor functional outcomes and second ACL injury risk.

Methods/Design

80 athletes that have undergone a unilateral ACLR and wish to return to level 1 or 2 activities will be recruited for this study and randomized to one of two treatment groups. A standard care group will receive prevention exercises, quadriceps strengthening and agility exercises, while the perturbation group will receive the same exercise program with the addition of perturbation training. The primary outcomes measures will include gait biomechanics, clinical and functional measures, and knee joint loading. Return to sport rates, return to pre-injury level of activity rates, and second injury rates will be secondary measures.

Discussion

The results of this ACL-Specialized Post-Operative Return To Sports (ACL-SPORTS) Training program will help clinicians to better determine an effective post-operative treatment program that will improve modifiable impairments that influence outcomes after ACLR.

Trial registration

Randomized Control Trial NIH 5R01AR048212-07. ClinicalTrials.gov: NCT01773317

Biomechanical comparison of femoral fixation devices for anterior cruciate ligament reconstruction using a novel testing method

BACKGROUND

A novel biomechanical test method was implemented to compare the mechanical performance of two femoral fixation anchors (AperFix(r), Cayenne Medical, Scottsdale, AZ, USA or the AppianFx(r), KFx Medical, Carlsbad, CA, USA) that were utilized in anterior cruciate ligament reconstruction.

METHODS

Anterior cruciate ligament reconstructions were performed in 20 porcine femurs by using bovine extensor tendon grafts secured with 9 mm femoral anchors (AperFix(r) or AppianFx(r)). 10 specimens were tested for each anchor type. Infrared position sensors determined the repair construct displacements during conditioning (20 cycles at 5-50 N at 0.25 Hz), cyclic loading (1500 cycles at 50-200 N at 1 Hz), and ultimate loading (150 mm/min). Outcomes included tendon elongation, anchor displacement, stiffness, maximum load, yield load, and load at 5mm of anchor displacement. It was hypothesized that there would be no differences in the outcomes of these two devices. Independent measure t-tests compared the performance of the devices (p<0.05).

FINDINGS

The performance of the two anchors was comparable during the cyclic loading. During ultimate loading, a statistically higher yield load (p<0.01) and a load at 5mm of anchor displacement (p<0.01) were demonstrated for the AppianFx(r) as compared to AperFix(r). Maximum load and stiffness were not significantly different.

INTERPRETATION

Given the good clinical track record of the AperFix(r), the comparable, and in some cases superior, the biomechanical data presented here for the AppianFx(r) are encouraging for their clinical implementation. This study also introduced a novel test method that directly tracks the relevant construct displacements during cyclic and ultimate loading tests of the anterior cruciate ligament reconstructions.