Primary versus single-stage revision anterior cruciate ligament reconstruction using autologous hamstring tendon grafts: a prospective matched-group analysis

Preservation of the MMPH and Status of the Notch Configurations Are Important Factors for Successful Revision ACL Reconstruction

OBJECTIVE

The aim of this study was to identify the differences in anatomical factors between the patients who underwent revision and primary anterior cruciate ligament reconstructions (ACLR) and compare the outcomes between the 2 surgeries.

DESIGN

Retrospective cohort study.

SETTING

Single institution tertiary academic center between 2014 and 2020.

PATIENTS

A total of 84 matched patients who underwent revision (group I) or primary ACLR (group II).

INTERVENTIONS

Radiological evaluations were performed using side-to-side differences (SS-D), femorotibial angle, and posterior tibial slope. The medial meniscus posterior horn status as width (MMPHW), medial tibial plateau width (MTPW), notch configurations, tunnel positions, and sagittal graft angle were measured using 3D-CT and magnetic resonance imaging (MRI).

MAIN OUTCOME MEASURES

Graft signals were assessed using MRI. The clinical outcomes were assessed.

RESULTS

Group I showed larger SS-D and higher mean Howell grade of anterior cruciate ligament (ACL) graft than group II ( P = 0.002 and P = 0.004, respectively). Multivariate regression analyses showed that the decreased MMPHW/MTPW ratio ( P = 0.010) and notch width index ( P < 0.007) were significantly independent factors associated with the higher Howell grade of ACL grafts. The decreased MMPHW/MTPW ratio ( P < 0.001) was a significantly independent factor associated with larger SS-D. In the subgroup analysis, all patients in the notchplasty group showed wider notches postoperatively ( P < 0.001).

CONCLUSIONS

Revision ACLRs resulted in worse ACL signal intensity and stability outcome. The results of this study suggest that it may be important to preserve the MMPHW as much as possible and check notch configurations, especially during a revision ACLR.

Revision ACL reconstruction, but not bilateral ACL reconstruction, is associated with clinically relevant inferior subjective knee function compared with primary ACL reconstruction: A comparative analysis of 6831 patients

PURPOSE

To evaluate and compare the subjective knee function in patients undergoing revision and bilateral anterior cruciate ligament (ACL) reconstruction (ACLR) with those undergoing primary ACLR in a large cohort.

METHODS

Patients without concomitant ligament injuries who underwent primary, revision or bilateral ACLR at the Capio Artro Clinic, Stockholm, Sweden, between 2005 and 2018 were identified. The Knee injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and at 1, 2 and 5 years postoperatively from the Swedish National Knee Ligament Registry. Patients who underwent revision and bilateral ACLR were compared with those who underwent primary ACLR (control group) using Student's t test.

RESULTS

A total of 6831 patients (6102 with primary ACLRs, 343 with revision ACLRs and 386 with bilateral ACLRs) were included. Preoperatively, there were significant but nonclinically relevant differences in favour of the revision ACLR group for KOOS Symptoms, Pain, Activities of Daily Living (ADL) and Sport/Rec subscale scores compared with the primary ACLR group. Postoperatively, except for the 1-year Symptoms and ADL subscales, the revision ACLR group reported significantly lower scores on all KOOS subscales than the primary ACLR group, with clinically relevant differences (>8-10 points) for the 1-, 2- and 5-year Sport/Rec and Quality of Life (QOL) subscales. The bilateral ACLR group reported significantly, but not clinically relevant, inferior scores on the 1-year Symptoms and QOL subscales and the 5-year Sport/Rec and QOL subscales compared with the primary ACLR group.

CONCLUSIONS

Revision ACLR, but not bilateral ACLR, was associated with clinically relevant inferior subjective knee function compared with primary ACLR. It is important to counsel patients regarding their future subjective knee function after repeated ACLR. Compared to primary ACLR, inferior subjective results should be expected after revision ACLR, but not after bilateral ACLR.

LEVEL OF EVIDENCE

Level III.

Primary Versus Revision ACL Reconstruction Using Quadriceps Autograft: A Matched-Control Cohort Study

Background

The incidence of anterior cruciate ligament (ACL) reconstruction is increasing, and quadriceps tendon (QT) autograft is gaining popularity for both primary and revision ACL reconstruction.

Purpose

To evaluate the differences in the patient-reported functional outcomes, concomitant injuries, and graft failure in primary versus revision ACL surgery using QT autograft.

Study Design

Cohort study; Level of evidence, 3.

Methods

A total of 376 patients with primary ACL reconstruction and 138 patients with revision ACL reconstruction were retrospectively retrieved from a prospectively collected ACL registry. A minimally invasive technique was used for QT autograft harvesting. The surgical procedure and rehabilitation protocol were identical in both groups. To maintain a homogeneous cohort for the study, the groups were matched by age, sex, and preinjury outcome scores (Lysholm knee score, Tegner activity level, and visual analog scale [VAS] for pain). Initial baseline assessments of outcome scores were compared with scores collected at the 2-year postoperative mark.

Results

The mean age of the primary group and revision group was 32.9 ± 10.2 years (range, 18-55 years) and 32.3 ± 9.9 years (range, 19-55 years) respectively. Significant preinjury to postoperative improvements were noted in Lysholm (88.2 ± 16.4 vs 83.5 ± 15.0; P = .007) and VAS pain (0.9 ± 1.3 vs 1.5 ± 1.6; P = .001) scores after primary ACL reconstruction compared with revision reconstruction. However, no significant difference was found in Tegner activity level (6.7 ± 1.8 vs 5.9 ± 1.8; P > .430). Primary ACL injury was associated with significantly higher concomitant medial collateral ligament injuries (P = .019), while the revision group was associated with significantly higher concomitant cartilage (P = .001) and meniscal (P = .003) injuries. A significantly higher graft failure rate was noted in the revision group compared with the primary ACL reconstruction group (13.0% vs 5.6%; P = .005).

Conclusion

Both primary and revision ACL reconstruction with QT autograft had acceptable functional outcomes. The primary group had better outcomes than the revision group, possibly due to the lower prevalence of meniscal and cartilage injuries in the primary group compared with the revision group. The revision group was associated with higher graft failure than the primary group. QT autograft is a viable graft choice for both primary and revision ACL reconstruction.

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.

Comparison of Onlay Anchor Fixation Versus Transosseous Fixation for Lateral Extra-articular Tenodesis During Revision ACL Reconstruction

Background

There is evidence on the clinical effectiveness of the Lemaire technique for lateral extra-articular tenodesis (LET) in patients undergoing revision anterior cruciate ligament reconstruction (ACLR), but the best fixation technique is unknown.

Purpose

To compare the clinical outcomes of 2 fixation techniques after revision ACLR: (1) onlay anchor fixation, which would avoid tunnel conflict and physis injury, and (2) transosseous tightening and interference screw fixation. Pain at the area of LET fixation was also assessed.

Study Design

Cohort study; Level of evidence, 3.

Methods

This was a retrospective 2-center study of patients with first-time revision ACLR and either LET with anchor fixation (aLET) with a 2.4-mm suture anchor or LET with transosseous fixation (tLET). Outcomes at minimum 12-month follow-up were assessed with the International Knee Documentation Committee score, Knee injury and Osteoarthritis Outcome Score, visual analog scale for pain at the LET fixation area, Tegner score, and anterior tibial translation (ATT). A subgroup analysis within the aLET group investigated passing the graft over or under the lateral collateral ligament (LCL).

Results

In total, 52 patients were included (26 patients in each group); the mean ± SD follow-up was 13.7 ± 3.4 months. No statistically significant differences were detected between the groups with respect to patient-reported outcome scores, clinical examination, or instrumented testing (side-to-side difference in ATT at 30° of flexion; aLET, 1.5 ± 2.5 mm; tLET, 1.6 ± 1.7 mm). Clinical failure was detected in 1 patient with aLET and none with tLET. Subgroup analysis revealed a small, nonsignificant flexion deficit in knees in which the iliotibial band strand was passed under (n = 42) or over (n = 10) the LCL. No clinically relevant tenderness was detected at the area of LET fixation in any group (aLET, 0.6 ± 1.3; tLET, 0.9 ± 1.7; over the LCL, 0.2 ± 0.6; under the LCL, 0.9 ± 1.6).

Conclusion

Onlay anchor fixation and transosseous fixation of the LET were equivalent with respect to outcome scores and instrumented ATT testing. Clinically, there were minor differences in passage of the LET graft over or under the LCL.

State of the mineralized tissue comprising the femoral ACL enthesis in young women with an ACL failure

Despite poor graft integration among some patients that undergo an anterior cruciate ligament (ACL) reconstruction, there has been little consideration of the bone quality into which the ACL femoral tunnel is drilled and the graft is placed. Bone mineral density of the knee decreases following ACL injury. However, trabecular and cortical architecture differences between injured and non-injured femoral ACL entheses have not been reported. We hypothesize that injured femoral ACL entheses will show significantly less cortical and trabecular mass compared with non-injured controls. Femoral ACL enthesis explants from 54 female patients (13-25 years) were collected during ACL reconstructive surgery. Control explants (n = 12) were collected from seven donors (18-36 years). Injured (I) femoral explants differed from those of non-injured (NI) controls with significantly less (p ≤ 0.001) cortical volumetric bone mineral density (vBMD) (NI: 736.1-867.6 mg/cm3 ; I: 451.2-891.9 mg/cm3 ), relative bone volume (BV/TV) (NI: 0.674-0.867; I: 0.401-0.792) and porosity (Ct.Po) (NI: 0.133-0.326; I: 0.209-0.600). Injured explants showed significantly less trabecular vBMD (p = 0.013) but not trabecular BV/TV (p = 0.314), thickness (p = 0.412), or separation (p = 0.828). We found significantly less cortical bone within injured femoral entheses compared to NI controls. Lower cortical and trabecular bone mass within patient femoral ACL entheses may help explain poor ACL graft osseointegration outcomes in the young and may be a contributor to the osteolytic phenomenon that often occurs within the graft tunnel following ACL reconstruction.

Quadriceps tendon autograft is becoming increasingly popular in revision ACL reconstruction

PURPOSE

To evaluate trends in revision anterior cruciate ligament reconstruction (ACL-R), with emphasis on intra-articular findings, grafts, and concurrent procedures. It was hypothesized that revision ACL-Rs over time show a trend toward increased complexity with increased use of autografts over allografts.

METHODS

This was a two-center retrospective study including patients undergoing revision ACL-R between 2010 and 2020. Demographic and surgical data including intra-articular findings and concurrent procedures were collected and compared for the time periods 2010-2014 and 2015-2020. All collected variables were compared between three pre-defined age groups (< 20 years, 20-30 years, > 30 years), right and left knees, and males and females. A time series analysis was performed to assess trends in revision ACL-R.

RESULTS

This study included 260 patients with a mean age of 26.2 ± 9.4 years at the time of the most recent revision ACL-R, representing the first, second, third, and fourth revision ACL-R for 214 (82%), 35 (14%), 10 (4%), and 1 (< 1%) patients, respectively. Patients age > 30 years showed a significantly longer mean time from primary ACL-R to most recent revision ACL-R (11.1 years), compared to patients age < 20 years (2.2 years, p < 0.001) and age 20-30 years (5.5 years, p < 0.05). Quadriceps tendon autograft was used significantly more often in 2015-2020 compared to 2010-2014 (49% vs. 18%, p < 0.001). A high rate of concurrently performed procedures including meniscal repairs (45%), lateral extra-articular tenodesis (LET; 31%), osteotomies (13%), and meniscal allograft transplantations (11%) was shown. Concurrent LET was associated with intact cartilage and severely abnormal preoperative knee laxity and showed a statistically significant and linear increase over time (p < 0.05). Intact cartilage (41%, p < 0.05), concurrent medial meniscal repairs (39%, p < 0.05), and LET (35%, non-significant) were most frequently observed in patients aged < 20 years.

CONCLUSION

Quadriceps tendon autograft and concurrent LET are becoming increasingly popular in revision ACL-R. Intact cartilage and severely abnormal preoperative knee laxity represent indications for LET in revision ACL-R. The high rate of concurrent procedures observed demonstrates the high surgical demands of revision ACL-R.

LEVEL OF EVIDENCE

Level III.

Laxity measurement of internal knee rotation after primary anterior cruciate ligament rupture versus rerupture

PURPOSE

The aim of the current study was to objectify the rotational laxity after primary anterior cruciate ligament (ACL) rupture and rerupture after ACL reconstruction by instrumented measurement. It was hypothesized that knees with recurrent instability feature a higher internal rotation laxity as compared to knees with a primary rupture of the native ACL.

STUDY DESIGN

Cross-sectional study, Level of evidence III.

METHODS

In a clinical cross-sectional study successive patients with primary ACL rupture and rerupture after ACL reconstruction were evaluated clinically and by instrumented measurement of the rotational and antero-posterior laxity with a validated instrument and the KT1000^®, respectively. Clinical examination comprised IKDC 2000 forms, Lysholm Score, and Tegner Activity Scale. Power calculation and statistical analysis were performed (p value < 0.05).

RESULTS

24 patients with primary ACL rupture and 23 patients with ACL rerupture were included. There was no significant side-to-side difference in anterior translation. A side-to side difference of internal rotational laxity ≥ 10° was found significantly more frequent in reruptures (53.6%) compared to primary ruptures (19.4%; p < 0.001). A highly significant relationship between the extent of the pivot-shift phenomenon and side-to-side difference of internal rotation laxity could be demonstrated (p < 0.001). IKDC 2000 subjective revealed significantly better scores in patients with primary ACL tear compared to patients with ACL rerupture (56.4 ± 7.8 vs. 50.8 ± 6.2; p = 0.01). Patients with primary ACL tears scored significantly better on the Tegner Activity Scale (p = 0.02). No significant differences were seen in the Lysholm Score (p = 0.78).

CONCLUSION

Patients with ACL rerupture feature significantly higher internal rotation laxity of the knee compared to primary ACL rupture. The extend of rotational laxity can be quantified by instrumented measurements. This can be valuable data for the indication of an anterolateral ligament reconstruction in ACL revision surgery.

Revision Anterior Cruciate Ligament Reconstruction after Surgical Management of Multiligament Knee Injury

The purpose of this study is to determine factors associated with the need for revision anterior cruciate ligament reconstruction (ACLR) after multiligament knee injury (MLKI) and to report outcomes for patients undergoing revision ACLR after MLKI. This involves a retrospective review of 231 MLKIs in 225 patients treated over a 12-year period, with institutional review board approval. Patients with two or more injured knee ligaments requiring surgical reconstruction, including the ACL, were included for analyses. Overall, 231 knees with MLKIs underwent ACLR, with 10% (n = 24) requiring revision ACLR. There were no significant differences in age, sex, tobacco use, diabetes, or body mass index between cohorts requiring or not requiring revision ACLR. However, patients requiring revision ACLR had significantly longer follow-up duration (55.1 vs. 37.4 months, p = 0.004), more ligament reconstructions/repairs (mean 3.0 vs. 1.7, p < 0.001), more nonligament surgeries (mean 2.2 vs. 0.7, p = 0.002), more total surgeries (mean 5.3 vs. 2.4, p < 0.001), and more graft reconstructions (mean 4.7 vs. 2.7, p < 0.001). Patients in both groups had similar return to work (p = 0.12) and activity (p = 0.91) levels at final follow-up. Patients who had revision ACLR took significantly longer to return to work at their highest level (18 vs. 12 months, p = 0.036), but similar time to return to their highest level of activity (p = 0.33). Range of motion (134 vs. 127 degrees, p = 0.14), pain severity (2.2 vs. 1.7, p = 0.24), and Lysholm's scores (86.3 vs. 90.0, p = 0.24) at final follow-up were similar between groups. Patients requiring revision ACLR in the setting of a MLKI had more overall concurrent surgeries and other ligament reconstructions, but had similar final outcome scores to those who did not require revision surgery. Revision ligament surgery can be associated with increased pain, stiffness, and decrease patient outcomes. Revision surgery is often necessary after multiligament knee reconstructions, but patients requiring ACLR in the setting of a MLKI have good overall outcomes, with patients requiring revision ACLR at a rate of 10%.

Revision Anterior Cruciate Ligament Reconstruction: Tibial Tunnel-First Graft-Sizing Technique

Revision anterior cruciate ligament reconstruction (R-ACLR) has become more common as the number of failed primary ACLRs increase. Although increasingly common, R-ACLR has a greater failure rate than a primary reconstruction. Technical errors, particularly in tunnel placement, account for a large proportion of graft failure in R-ACLR as well as re-revision cases. Tunnel placement and trajectory is particularly important in R-ACLR and becomes more challenging with each additional revision attempt. This is in part because any tunnels created for revision may converge with formerly drilled tunnels or face interference hardware creating, complicating proper graft fixation. While there are many approaches to revision ACL surgery, our technique describes a simple, tibial tunnel-first graft-sizing method initially reaming tunnels with very small diameters and sequentially working your way up to more anatomic diameters.

The 50 Most Cited Articles in the Indications, Risk Factors, Techniques, and Outcomes of ACL Revision Surgery

The rate of anterior cruciate ligament (ACL) retear remains high and revision ACL reconstruction has worse outcomes compared with primaries. To make advances in this area, a strong understanding of influential research is necessary. One method for systematically evaluating the literature is by citation analysis. This article aims to establish and evaluate "classic" articles. With consideration of these articles, this article also aims to evaluate gaps in the field and determine where future research should be directed. The general approach for data collection and analysis consisted of planning objectives, employing a defined strategy, reviewing search results using a multistep and multiauthor approach with specific screening criteria, and analyzing data. The collective number of citations for all publications within the list was 5,203 with an average of 104 citations per publication. "Biomechanical Measures during Landing and Postural Stability Predict Second Anterior Cruciate Ligament Injury after Anterior Cruciate Ligament Reconstruction and Return to Sport" by Paterno et al contained both the highest number of total citations and the highest number of citations per year, with 403 total citations and 43.9 citations per year. The most recurring level of evidence were level II (n = 18) and level III (n = 17). "Clinical Outcomes" was the most common article type (n = 20) followed by "Risk Factors" (n = 10). The American Journal of Sports Medicine had the highest recorded Cite Factor with over 50% of the articles (n = 27) published. The most productive authors included R.W. Wright (n = 6), S.D. Barber-Westin (n = 5), F.R. Noyes (n = 5), and K.P. Spindler (n = 5). Historically, influential studies have been published in the realms of clinical outcome and risk factor identification. It has been established that revision ACL reconstruction has worse outcomes and more high-level studies are needed. Additionally, prospective studies that apply the knowledge for current known risk factor mitigation are needed to determine if graft tear rates can be lowered.

Stacked Biocomposite Screws in a Single-Stage Revision Anterior Cruciate Ligament Reconstruction Has Acceptable Fixation Strength in a Porcine Cadaveric Model

BACKGROUND

Stacked screws is a commonly used technique in single-stage revision anterior cruciate ligament (ACL) reconstruction in the setting of bone loss, but there are limited data to support its use.

HYPOTHESIS

Two configurations of a biocomposite stacked screws construct have similar fixation strength and linear stiffness as a primary ACL reconstruction construct in a biomechanical model.

STUDY DESIGN

Controlled laboratory study.

METHODS

A total of 30 porcine legs were divided into 3 groups. Group 1 underwent primary ACL reconstruction with a patellar tendon graft fixed into the femur, with an 8-mm biocomposite interference screw of beta-tricalcium phosphate and poly lactide-co-glycolide. For a revision ACL reconstruction model, groups 2 and 3 had bone tunnels created and subsequently filled with 12-mm biocomposite screws. New bone tunnels were drilled through the filler screw and the surrounding bone, and the patellar bone plug was inserted. Group 2 was fixed with 8-mm biocomposite screws on the side of the graft opposite the filler screw, while group 3 had the interference screw interposed between the graft and the filler screw. The construct was loaded at 1.5 mm/s in line with the tunnel until failure. Load to failure, linear stiffness, and mode of failure were recorded.

RESULTS

The mean pullout strength for groups 1, 2, and 3 was 626 ± 145 N, 653 ± 152 N, and 720 ± 125 N, respectively (P = .328). The mean linear stiffness of the construct in groups 1, 2, and 3 was 71.4 ± 9.9 N/mm, 84.1 ± 11.1 N/mm, and 82.0 ± 10.8 N/mm, respectively. Group 2 was significantly stiffer than group 1 (P = .037).

CONCLUSION

Two configurations of a biocomposite stacked screws construct for a single-stage revision ACL reconstruction in the setting of bone loss show a similar fixation strength and linear stiffness to a primary ACL reconstruction at time zero in a porcine model.

CLINICAL RELEVANCE

In the setting of bone loss from tunnel malpositioning, a single-stage revision ACL reconstruction using a stacked screws construct may provide adequate fixation strength and linear stiffness.

Outcomes of 1- Versus 2-Stage Revision Anterior Cruciate Ligament Reconstruction: A Systematic Review and Meta-analysis

BACKGROUND

Anterior cruciate ligament reconstruction (ACLR) is a common orthopaedic sports medicine procedure, but graft failure is not uncommon and often leads to revision ACLR. Revision surgery can be performed in a 1- or 2-stage fashion.

HYPOTHESIS

Graft failure risk, patient-reported outcomes, and anterior knee laxity are similar after 1- and 2-stage revision ACLR.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A systematic review of the literature was performed to evaluate patient outcomes after 1- versus 2-stage revision ACLR. A search was performed with the phrase "revision anterior cruciate ligament reconstruction" across Embase, PubMed, Scopus, and SportDiscus from the beginning of their archives through July 12, 2019.

RESULTS

Thirteen studies met inclusion criteria and included 524 patients: 319 patients who underwent 1-stage revision ACLR and 205 patients who underwent 2-stage revision ACLR. Two studies compared outcomes of 1- versus 2-stage revision ACLR; 4 studies reported outcomes after 2-stage revision ACLR; and the remaining 7 studies documented outcomes after 1-stage ACLR. The mean follow-up was 4.1 years. The 2 studies that compared 1- versus 2-stage ACLR reported no differences in functional, radiologic, or patient-reported outcomes or failure risk. Overall, 9 studies reported subjective International Knee Documentation Committee (IKDC) scores; 4 studies, Knee injury and Osteoarthritis Outcome Score values; 8 studies, Lysholm scores; and 7 studies, Tegner scores; 8 studies measured anterior laxity with a KT-1000 arthrometer. The mean weighted subjective IKDC score for all studies including this outcome at final follow-up was 66.6 for 1-stage revisions and 65.9 for 2-stage revisions.

CONCLUSION

The available evidence comparing 1- versus 2-stage revision ACLR is retrospective and limited. The results of each approach are similar in appropriately selected patients.

Knee laxity and functional knee outcome after contralateral ACLR are comparable to those after primary ACLR

PURPOSE

To evaluate and compare knee laxity and functional knee outcome between primary and contralateral anterior cruciate ligament (ACL) reconstruction.

METHODS

Patients who underwent primary and subsequent contralateral ACL reconstruction (ACLR) at Capio Artro Clinic, Stockholm, Sweden, from 2001 to 2017, were identified in our local database. The inclusion criteria were: the same patients who underwent primary and contralateral hamstring tendon or bone-patellar tendon-bone autograft ACLR and no associated ligament injuries. The KT-1000 arthrometer, with an anterior tibial load of 134 N, was used to evaluate knee laxity preoperatively and 6 months postoperatively. The Knee injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and at the 1-year follow-up.

RESULTS

A total of 326 patients with isolated primary and contralateral ACLR met the inclusion criteria (47.9% males; mean age at primary ACLR 23.9 ± 9.4 years and contralateral ACLR 27.9 ± 10.1 years). The arthrometric laxity measurements were available for primary and contralateral ACLR for 226 patients. The mean preoperative and postoperative anterior tibial translation (ATT), as well as the mean ATT reduction from preoperatively to postoperatively, did not differ significantly between primary and contralateral ACLR. The KOOS was available for primary and contralateral ACLR for 256 patients. No significant differences were found preoperatively and at the 1-year follow-up between primary and contralateral ACLR for any of the five KOOS subscales.

CONCLUSION

The findings in this study showed that anterior knee laxity and functional knee outcome after contralateral ACLR are comparable to those after primary ACLR. It is important for clinicians to counsel patients about their expectations after contralateral ACLR. This study shows that the results after contralateral ACLR in terms of knee laxity and functional knee outcome are predictable and likely to be comparable to those after primary ACLR.

LEVEL OF EVIDENCE

Level III.

Economic Reliable Technique for Tunnel Grafting Using Iliac Crest Bone Graft in Two-Staged Revision Anterior Cruciate Ligament Surgery

Revision anterior cruciate ligament surgery is a technically demanding procedure. Mal-positioned tunnels together with bone loss and its management are some of the difficulties and challenges faced. Two-staged procedures have successfully been used to tackle those challenges. We present a technique that is safe, reliable, reproducible, and economic in the management of bone defects faced in anterior cruciate ligament revision surgery by using iliac crest bone graft. Preoperative assessment of tunnel position and size is done by computed tomography. Tri-cortical iliac crest bone graft is harvested through a trap door. It is then shaped to fit the tunnels to be filled. It is tapered at the advancing end to facilitate introduction. Mounted on a passing pin and a drill bit, the graft is arthroscopically introduced into the femoral and tibial tunnels. The second stage is performed after the graft has incorporated, as seen on postoperative computed tomography, done at approximately 3 months after the first stage. Iliac crest provides a natural abundant reservoir for bone graft and has all the advantages of being an autograft. With good meticulous technique, complications can be avoided with less donor-site morbidity. This technique is safe, reliable, and reproducible. It provides an ample amount of graft and harvest does not rely on implants; hence, it is economic.

Slope-Reducing Tibial Osteotomy Combined With Primary Anterior Cruciate Ligament Reconstruction Produces Improved Knee Stability in Patients With Steep Posterior Tibial Slope, Excessive Anterior Tibial Subluxation in Extension, and Chronic Meniscal Posterior Horn Tears

BACKGROUND

Steep posterior tibial slope (PTS; >13°), excessive anterior tibial subluxation (ATS) in extension (>10 mm), and meniscus posterior horn tears (MPHTs) have been identified to be associated with primary anterior cruciate ligament (ACL) reconstruction (ACLR) failure. Recent studies have reported that steep PTS is directly correlated with excessive ATS in extension and concomitant MPHTs, especially for those patients with chronic (>6 months) ACL deficiency. There is increasing biomechanical evidence that slope-reducing tibial osteotomy decreases ATS in extension and protects the ACL graft.

HYPOTHESIS

Slope-reducing tibial osteotomy combined with primary ACLR is effective for producing improved knee stability in patients with steep PTS (>13°), excessive ATS in extension (>10 mm), and concomitant chronic MPHTs (>6 months).

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between June 2016 and January 2018, 18 patients with ACL injuries who had steep PTS (>13°), excessive ATS in extension (>10 mm), and concomitant chronic MPHTs (>6 months) underwent slope-reducing tibial osteotomy combined with primary ACLR. The PTS and anterior subluxation of the lateral and medial compartment (ASLC and ASMC) in extension before and after the index procedures were regarded as primary clinical outcomes. Moreover, Lysholm score, Tegner activity score, International Knee Documentation Committee (IKDC) objective grade, pivot-shift test, and KT-1000 side-to-side difference were evaluated preoperatively and at the minimum 2-year follow-up visit.

RESULTS

The mean PTS was 18.5° (range, 17°-20°) preoperatively and 8.1° (range, 7°-9°) postoperatively (P < .01). The mean ASLC and ASMC in extension were 12.1 mm and 11.9 mm preoperatively, which reduced to 1.0 mm and 1.5 mm at the last follow-up visit (P < .05). In addition, all of the following showed significant improvements (pre- vs postoperatively): mean Lysholm score (46.5 vs 89.5; P < .05), mean Tegner activity score (5.7 vs 7.3; P < .05), IKDC objective grading results (18 grade D vs 14 grade A and 4 grade B; P < .05), pivot-shift tests (15 grade 2+ and 3 grade 3+ vs 18 grade 0; P < .01), and KT-1000 side-to-side difference (13.0 mm vs 1.6 mm; P < .01). Moreover, no graft reruptures were found at the final follow-up visit.

CONCLUSION

In this study, slope-reducing tibial osteotomy combined with primary ACLR effectively improved knee stability in patients with steep PTS (>13°), excessive ATS in extension (>10 mm), and concomitant chronic MPHTs (>6 months).

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.

Two-stage revision anterior cruciate ligament reconstruction: Our experience using allograft bone dowels

The incidence of anterior cruciate ligament reconstruction (ACLR) is continuously increasing. As a result so has the need for revision ACLR, which unfortunately has worse functional outcomes and rate of return to sport. Revision ACLR can be performed as a single stage or in two stages. The latter is recommended in the presence of enlarged and/or malpositioned tunnels. We describe our surgical technique, experience and outcome of our first 19 patients in whom we used allograft bone dowels in the first stage of revision ACLR.

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.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction: A Systematic Review of Bone Graft Options for Tunnel Augmentation

BACKGROUND

No consensus is available regarding the optimal choice of bone graft material for bone tunnel augmentation in revision anterior cruciate ligament (ACL) surgery.

PURPOSE

To compare the outcomes of different bone graft materials for staged revision ACL reconstruction.

STUDY DESIGN

Systematic review.

METHODS

A systematic review using PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines was performed. PubMed, EMBASE, and the Cochrane Library were queried through use of the terms anterior cruciate ligament and revision to identify all studies reporting outcomes of bone tunnel grafting in 2-stage revision ACL reconstruction. Data extracted included indications for 2-stage surgery, surgical technique, graft material, time between surgeries, rehabilitation protocols, physical examination findings, patient-reported outcomes, and radiographic and histologic findings.

RESULTS

The analysis included 7 studies with a total of 234 patients. The primary outcome in 2 studies was graft incorporation (mean follow-up, 8.8 months), whereas the other 5 studies reported clinical outcomes with follow-up mean ± SD of 4.2 ± 2.1 years. The indication for bone grafting and between-stage protocol varied among studies. Autograft was used in 4 studies: iliac crest bone autograft (ICBG, n = 3) and tibial bone autograft (TBA, n = 1). In 2 studies, the authors investigated the outcomes of allograft: allograft bone matrix (ABM) and allograft bone chips (AC). Finally, 1 study compared ICBG to a synthetic bone substitute. Radiographic evaluation of bone graft integration after the first stage was reported in 4 studies, with an average duration of 4.9 months. In 4 studies, the authors reported the time interval between first and second surgeries, with an average of 6.1 months for ICBG compared with 8.7 months for allogenic and synthetic grafts. Revision ACL graft failure rates were reported by 5 studies, including 1 study with ABM (6.1%), 1 study with AC (8.3%), 1 study with TBA (0%), and 2 studies with ICBG (0% and 2%).

CONCLUSION

The indications for staged ACL reconstruction and the rehabilitation protocol between stages need to be clearly established. The available data indicate that autograft for bone tunnel grafting in 2-stage ACL revision may be associated with a lower risk of revision ACL reconstruction graft failure compared with allograft bone.

Cancellous allogenic and autologous bone grafting ensure comparable tunnel filling results in two-staged revision ACL surgery

OBJECTIVES

Patients with recurrent instability after anterior cruciate ligament (ACL) reconstruction often present with enlarged or misplaced tunnels and bone grafting is required prior to the actual revision reconstruction. Autologous bone grafting features limited quantity and donor site morbidity. These problems may be eliminated utilizing cancellous bone allografts, but their efficiency and reliability have not been investigated systematically. The aim of the present study was to compare tunnel filling rates attained by utilizing either allogenic or autologous cancellous bone grafts.

MATERIALS AND METHODS

A total of 103 consecutive patients were enrolled retrospectively. All patients suffered from recurrent instability and underwent either allogenic or autologous cancellous bone grafting. Computed tomography (CT) was carried out before and after the bone grafting procedure. Based on preoperative CT scans, positioning and maximum diameter of the femoral and tibial tunnels were determined. Tunnel filling rates were calculated as a ratio of pre- and postoperative tunnel volumes. Primary outcome was the tibial tunnel filling rate. Femoral filling rates and density of the grafted bone were assessed secondarily.

RESULTS

Preoperative CT scans revealed no significant differences between the two groups regarding distribution of misplacement and widening of the femoral or tibial tunnel. Postoperative CT scans were conducted after an interval of 5.2 months. Tunnel filling rates of 74.5% (± 14.3) femoral and 85.3% (± 10.3) tibial were achieved in the allogenic compared to 74.3% (± 15.9) femoral and 84.9% (± 9.4) tibial in the autologous group. With p values of 0.85 at the femur and 0.83 at the tibia, there were no significant differences between the groups. The density of the grafted bone revealed significantly higher values in the allogenic group.

CONCLUSIONS

Utilizing cancellous bone allografts in two-staged revision ACL surgery provides for sufficient and reproducible filling of enlarged or misplaced tunnels. The filling rates are comparable to those achieved with autologous bone grafting. Advantages of allografts are the unrestricted quantity and the absence of any harvesting procedure.

Autologous Bone Graft Versus Silicate-Substituted Calcium Phosphate in the Treatment of Tunnel Defects in 2-Stage Revision Anterior Cruciate Ligament Reconstruction: A Prospective, Randomized Controlled Study With a Minimum Follow-up of 2 Years

PURPOSE

To compare and evaluate knee laxity and functional outcomes between autologous bone graft and silicate-substituted calcium phosphate (Si-CaP) in the treatment of tunnel defects in 2-stage revision anterior cruciate ligament reconstruction (ACLR).

METHODS

This prospective, randomized controlled trial was conducted between 2012 and 2015 with a total of 40 patients who underwent 2-stage revision ACLR. The tunnels were filled with autologous iliac crest cancellous bone graft in 20 patients (control group) and with Si-CaP in the other 20 patients (intervention group). After a minimum follow-up period of 2 years, functional outcomes were assessed by KT-1000 arthrometry (side-to-side [STS] difference), the Tegner score, the Lysholm score, and the International Knee Documentation Committee score.

RESULTS

A total of 37 patients (follow-up rate, 92.5%) with an average age of 31 years were followed up for 3.4 years (range, 2.2-5.5 years). The KT-1000 measurement did not show any STS difference between the bone graft group (0.9 ± 1.5 mm) and the Si-CaP group (0.7 ± 2.0 mm) (P = .731). One patient in the intervention group (5%) had an STS difference greater than 5 mm. Both groups showed significant improvements in the Tegner score, Lysholm score, and International Knee Documentation Committee score from preoperative assessment to final follow-up (P ≤ .002), without any difference between the 2 groups (P ≥ .396). Complications requiring revision occurred in 4 control patients (22%) and in 2 patients in the intervention group (11%) (P = .660). No complications in relation to Si-CaP were observed.

CONCLUSIONS

Equivalent knee laxity and clinical function outcomes were noted 3 years after surgery in both groups of patients. Si-CaP bone substitute is therefore a safe alternative to autologous bone graft for 2-stage ACLR.

LEVEL OF EVIDENCE

Level I, prospective, randomized controlled clinical trial.

Revision ACL reconstruction using quadriceps or hamstring autografts leads to similar results after 4 years: good objective stability but low rate of return to pre-injury sport level

PURPOSE

Due to the increased importance of revision ACL reconstruction, this study aims to evaluate the outcome 4 years after the surgery, compare two revision strategies and identify factors that influence the results.

METHODS

Seventy-nine patients who received a revision ACL reconstruction were retrospectively evaluated. All patients were assessed with an average follow-up of 4.4 years (range 3.3-5.5 years). The results of patients treated with a quadriceps autograft were compared with those treated with a hamstring autograft.

RESULTS

Ninety-seven percent of patients had a KT-1000 side-to-side difference of ≤ 5 mm (mean 1.7 ± 2.0 mm). Pivot-shift test was absent or minor in 95%. In the SLTH-test, 70% of patients reached 90% of the contralateral side. The mean Lysholm score on follow-up was 83 ± 12 (56% excellent/good). The mean IKDC 2000 subjective evaluation score was 81 ± 14 (58% normal/almost normal). The median Tegner activity score was 6 (range 3-10), a median of 2 levels worse than before the first injury. Return to sport rate was 89% but only 34% of patients reached their pre-injury sport level. Most common cause for this reduction was fear of another injury. Three patients suffered a re-rupture. Patients with a hamstring autograft performed pivoting sports more often, but had worse pivot-shift results compared to those with a quadriceps autograft. No significant influence was seen for other parameters. Young, male patients with a high activity level and no chondral damage had the best results.

CONCLUSION

Through revision ACL reconstruction, the goal of stabilizing the knee can be achieved in the majority of patients. However, a good function and a high activity level are significantly less common in these patients. The main reason for this is fear of a renewed ACL-injury. Both quadriceps and hamstring autografts were able to achieve a good outcome. Young, male, patients with a normal BMI, a high activity level and without cartilage damage seem to benefit the most from revision ACL surgery. The discrepancy between the good laxity restoration and the lower activity rate should therefore be a main point in clinical counseling when deciding for or against revision ACL-Reconstruction.

LEVEL OF EVIDENCE

III.

Biomechanical comparison of different tendon suturing techniques for three-stranded all-inside anterior cruciate ligament grafts

OBJECTIVE

In all-inside anterior cruciate ligament (ACL) reconstruction, it is usually difficult to obtain sufficient autologous semitendinosus tendon length for quadruple stranded graft in Asians, females, and those with short stature. The purpose of this study was to compare biomechanical properties of three different types of suture preparations for tripled graft and determine which method could achieve sufficient strength for ACL through in vitro study. The hypothesis of this study was that suturing with a rip-stop (RS) stitch for tripled-strand graft would lead to stronger mechanical properties than suturing with buried-knot four sutures.

METHODS

Twenty-four bovine digital extensor tendons harvested from forelimbs were prepared for tripled-strand graft in three different ways: (1) buried-knot four sutures, (2) two RS sutures, and (3) four RS sutures. These grafts were directly connected to cylindrical metal rods of a tensile testing machine. All specimens underwent cyclic loading followed by a load-to-failure test. Preparation time, elongation, stiffness, and ultimate failure load were compared.

RESULTS

For biomechanical comparison, the group with buried-knot four sutures was excluded because six (75%) specimens failed during the cycle load test. The group with four RS sutures showed lower total elongation (two RS sutures: 8.42±5.28mm; four RS sutures: 3.86±0.83mm, p=0.030), higher stiffness (two RS sutures: 247.28±53.39N/mm; four RS sutures: 329.27±55.56N/mm, p<0.001), and higher ultimate failure load (two RS sutures: 567.74±60.50N; four RS sutures: 736.46±32.50N, p=0.009). The most common failure mechanism of triple stranded graft was tendon split across sutures.

CONCLUSION

The method with four RS sutures showed sufficient strength for triple stranded graft for all-inside ACL reconstruction without increasing preparation time.

LEVEL OF EVIDENCE

III, controlled laboratory study.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction Using Silicate-Substituted Calcium Phosphate

Revision surgery after failed primary anterior cruciate ligament reconstruction is technically demanding. In cases in which the tunnels of the primary anterior cruciate ligament reconstruction are widened to greater than 10 mm and/or are incorrectly positioned, a 2-stage procedure enables restoration of bone stock and thus free placement of the tunnels during the revision. The gold standard for tunnel augmentation is an autologous iliac crest cancellous bone graft. However, harvesting the graft is associated with high morbidity. This article describes an alternative method for managing bone deficiencies using the synthetic bone graft substitute silicate-substituted calcium phosphate.

Similar risk of ACL graft revision for alpine skiers, football and handball players: the graft revision rate is influenced by age and graft choice

Objectives

The risk of graft revision following ACL reconstruction may depend on the sport type the individuals are engaged in. The purpose of this study was to report the ACL graft revision rate in alpine skiers, football and handball players.

Materials and methods

Primary ACL reconstructions and graft revision data from 2004 to December 2016 were obtained from the Norwegian Cruciate Ligament Registry. The graft survival rates were calculated for individuals in each of the three sport types, for bone patellar tendon bone (BPTB) and hamstring tendons (HT) grafts separately, and related to age at primary operation and sex.

Results

A total of 711 grafts in 14 201 primary ACL reconstructions were revised (5.0%) after median 6 years, 3.8% in alpine skiers, 5.0% in soccer and 6.1% in handball players (p<0.001). Adjusted Cox regression showed similar ACL graft survival rates in the three groups. The HR for graft revision was 5 times higher for individuals aged ≤18 years than for those aged ≥35 years (p<0.001). The corresponding HR for graft type was 1.8 times higher for HT than for BPTB grafts (p<0.001), but 2.8 times higher for individuals aged ≤18 years (p<0.001). The 12 years survival of BPTB grafts was 96% compared with 93% for HT grafts (p <0.001).

Conclusion

The revision rate for ACL grafts was similar among alpine skiers, football and handball players, and the results support the use of BPTB grafts in young athletes with closed growth zones in the knee.

Study design

Cohort study; level of evidence, 2.

Outcome After Anterior Cruciate Ligament Revision

PURPOSE OF REVIEW

To describe the current literature related to anterior cruciate ligament (ACL) revision in terms of surgical aspects, graft choices, concomitant injuries, patient-reported outcome, return to sport, and objective measurement outcome.

RECENT FINDINGS

An ACL rupture is a common knee injury, and the number of primary ACL reconstructions is increasing, implying a subsequent increase of ACL revisions in the future. It is widely accepted that an ACL revision is surgically challenging with a myriad of graft options to choose from. In many cases, simultaneous injuries to the index limb including meniscal and chondral lesions, respectively, are observed in the setting of a secondary ACL injury. Furthermore, the general understanding is that an ACL revision results in inferior outcome compared with a primary ACL reconstruction. Surgical treatment of an ACL revision can be performed as one-stage or two-stage procedure depending on, for example, the presence of limb malalignments, concomitant injuries, and tunnel widening. Nonirradiated allografts and autologous patella tendon, hamstring tendon, and quadriceps tendon are feasible options for ACL revision. Concomitant injuries to the affected knee such as intraarticular chondral lesions are more common in the setting of an ACL revision compared with primary ACL reconstruction while a lower presence of concomitant meniscal pathology is reported at ACL revision. Patients undergoing ACL revision have lower clinical and patient-reported outcome and lower rates of return to sport when compared with primary ACL surgery cases. However, long-term follow-ups with large study cohorts evaluating outcome of ACL revision are limited. Further research is needed to confirm the present findings of this review.

Revision anterior cruciate ligament reconstruction restores knee laxity but shows inferior functional knee outcome compared with primary reconstruction

PURPOSE

To evaluate and compare knee laxity and functional knee outcome between primary and revision anterior cruciate ligament (ACL) reconstruction in the same cohort of patients.

METHODS

Patients who underwent primary and revision ACL reconstruction (ACLR) at Capio Artro Clinic, Stockholm, Sweden, from 2000 to 2015, were identified in our local database. Inclusion criteria were: same patients who underwent primary hamstring tendons (HT) and revision bone-patellar tendon-bone (BPTB) autograft ACLR, no associated ligament injuries and no contralateral ACL injuries/reconstructions. The cause of revision ACLR was graft rupture for all patients. The KT-1000 arthrometer, with an anterior tibial load of 134-N, was used to evaluate knee laxity preoperatively and 6-month postoperatively. The Knee Injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and at the 1-year follow-up.

RESULTS

A total of 118 patients with primary and revision ACLR arthrometric laxity measurements were available (51.0% males; mean age at primary ACLR 21.7 ± 7.1 years and revision ACLR 24.3 ± 7.5 years). The mean preoperative and postoperative anterior side-to-side (STS) difference values were not significantly different between primary and revision ACLR. However, primary ACLR showed a significantly higher frequency of postoperative anterior STS difference > 5 mm compared with revision ACLR (8.4 vs 5.0%; P = 0.02). The KOOS was available for primary and revision ACLR for 73 patients (55.4% males; mean age at primary ACLR 21.6 ± 7 years and revision ACLR 24.7 ± 7.3 years). Preoperatively, revision ACLR showed significantly higher scores in all KOOS subscales, except for the activity of daily living (ADL) subscale. For the primary ACLR, the improvement from preoperatively to the 1-year follow-up was significantly greater in all KOOS subscales and, the postoperative scores were superior for Pain, ADL and Sports subscales compared with revision ACLR.

CONCLUSIONS

The findings of this study showed that anterior knee laxity is restored with revision BPTB autograft ACLR after failed primary HT autograft ACLR, in the same cohort of patients. However, revision ACLR showed a significantly inferior functional knee outcome compared with primary ACLR. It is important for clinicians to inform and set realistic expectations for patients undergoing revision ACLR. Patients must be aware of the fact that having revision ACLR their knee function will not improve as much as with primary ACLR and the final postoperative functional outcome is inferior.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

One-stage revision anterior cruciate ligament reconstruction in cases with excessive tunnel osteolysis. Results of a new technique using impaction bone grafting

BACKGROUND

This level IV study describes a new one-stage procedure for revision ACL reconstruction in cases with extreme tunnel widening.

METHODS

Eight consecutively treated subjects requiring ACL revision and presenting with excessive tunnel widening (87.5% to 250% tunnel enlargement) were included in this study. The graft-tunnel mismatch was resolved in this one-stage revision procedure by the use of custom-made eight to 10 mm cylindrical shaped bone allografts in a press-fit construct with the ACL-graft in combination with the usual fixation devices for ACL-reconstruction. All subjects were evaluated pre-operatively and at a minimum follow-up of one year by the IKDC objective and subjective scores, KOOS, and Tegner activity scale.

RESULTS

Mean improvement was 24.8 ± 16.1 on the KOOS evaluation (P-value 0,006) and 38.1 ± 16.8 on the IKDC subjective score (P-value 0,001). The objective IKDC scores improved significantly with an average of one grade (P-value 0,038). Anterior laxity as determined on the KT-1000 arthrometer improved with an average of 3.63 mm compared to the situation before primary reconstruction, and the Pivot-shift test was negative in all but one patient after the revision procedure while positive in all patients before primary reconstruction.

CONCLUSION

This new surgical technique using eight to 10 mm allograft bone cylinders for the management of excessive tunnel enlargement at single stage revision ACL reconstruction delivers excellent results after minimum one year of follow-up. The results of this study have the potential to lower the threshold for one-stage surgery in ACL revision complicated by extreme tunnel widening.

Screw oversizing for anterior cruciate ligament graft fixation in primary and enlarged tibial tunnels: A biomechanical study in a porcine model

BACKGROUND

Ideal diameter for tibial interference screw fixation of the anterior cruciate ligament (ACL) graft remains controversial. Tibial graft fixation with screws matching the tunnel diameter vs. one-millimetre oversized screws were compared.

METHODS

In 32 cadaveric porcine tibiae, bovine extensor tendons with a diameter of eight millimetres were fixed in (I) a primary ACL reconstruction scenario with eight-millimetre tibial tunnels (pACL), with eight-millimetre (pACL-8) vs. nine-millimetre (pACL-9) screws, and (II) a revision ACL reconstruction scenario with enlarged tunnels of 10 mm (rACL), with 10-mm (rACL-10) vs. 11-mm (rACL-11) screws. Specimens underwent cyclic loading with low and high load magnitudes followed by a load-to-failure test. Graft slippage and ultimate failure load were recorded.

RESULTS

In comparison with matched-sized screws (pACL-8), fixation with oversized screws (pACL-9) showed with significantly increased graft slippage during cyclic loading at higher load magnitudes (1.19 ± 0.23 vs. 1.98 ± 0.67 mm; P = 0.007). There were no significant differences between the two screw sizes in the revision scenario (rACL-10 vs. rACL-11; P = 0.38). Graft fixation in the revision scenario resulted in significantly increased graft slippage in comparison with fixation in primary tunnels at higher loads (pACL vs. rACL; P = 0.004). Pull-out strengths were comparable for both scenarios and all screw sizes (P > 0.316).

CONCLUSIONS

Matched-sized interference screws provided better ACL graft fixation in comparison with an oversized screw diameter. In revision cases, the fixation strength of interference screws in enlarged tunnels was inferior to the fixation strength in primary tunnels.

Single-stage versus two-stage revision anterior cruciate ligament reconstruction: a systematic review

Importance

Despite advances in surgical techniques and postoperative rehabilitation, long-term anterior cruciate ligament (ACL) graft rupture rate remains high. The increasing number of primary ACL reconstructions in an ageing population will lead to increasing revision reconstructions. Revision cases may have higher failure rates and worse patient-reported outcomes compared with primaries. While two-stage revisions may be indicated in certain complex cases, whether this is comparatively equivalent or even superior to revisions done in a single stage would assist preoperative planning.

Objective

The objective of this systematic review was to analyse and compare patient-reported outcomes and failure rate of single-stage versus two-stage revision ACL reconstruction.

Evidence review

Using PubMed, MEDLINE Complete and Ovid MEDLINE databases, a review was performed using Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines to identify level I–IV outcomes of revision ACL reconstruction with a minimum follow-up of 24 months.

Findings

Three studies reported outcomes of two-stage revisions with mean follow-up of 61.6 months, while 21 studies reported single-stage revisions with mean follow-up of 47.4 months. Pooled rate of two-stage revisions was 3.1% compared with 6.8% in single-stage (p=0.068). Clinical failure was reported in 5.1% of 79 two-stage patients compared with 13.8% of 533 single-stage patients (p<0.05). Within the single-stage cohort, there was a greater clinical failure rate (+8.7%, p<0.05) for patients with less than 48 months follow-up. Those with > 48 months follow-up had a higher rerupture rate (+5%, p<0.05) and a significantly greater sum of squared deviations (p<0.05) compared with those with < 48 months follow-up. Patient-reported outcomes have demonstrated two-stage revision patients with higher IKDC A and B scores than single-stage.

Conclusions and relevance

Although two-stage revisions may be performed in more complex cases, there are limited short-term data available regarding their outcomes. Two-stage revisions demonstrated comparable clinical outcomes and lower rate of revision surgery and clinical failure compared with single-stage revisions. Studies with shorter follow-up (24–48 months) showed higher clinical failure rates. Those with longer follow-up (>48 months) showed higher graft rerupture rates. The decision to perform staged reconstruction should made on whether adequate tunnel placement and fixation can be established in a single setting.

Level of evidence

Level IV.

Quadruple Semitendinosus Graft Construct With Double Cortical Suspensory Fixation for Anterior Cruciate Ligament Reconstruction: A Biomechanical Study

The purpose of this study was to evaluate the biomechanical properties of a graft construct with quadrupled Semitendinosus and two cortical buttons with adjustable loops concerning elongation, stiffness and resistance. A total of 15 fresh human cadaveric semitendinosus tendons were quadrupled over the two adjustable loops and stitched at the tibial tip with a cerclage type suture. They underwent pre-tensioning at 300 N for 2 minutes followed by cyclic loading (1000 cycles between 50–250 N) and finally a load-to-failure test. Statistical analysis was performed using SPSS Statistics software and groups were compared using a paired t-test, with a significance level set at α = 0.05. Graft construct elongation after pre-tensioning at 300 N was 12.8 mm (9.3 mm–16.5 mm) and mean cyclic elongation 0.4 mm (0.2 mm–0.9 mm), considered significant (p < 0,001). The resistance and stiffness values were respectively 849.46 N (649.30 N-1027.90 N) and 221.49 N (178,30 N – 276.10 N). Quadruple ST graft construct using two cortical buttons and adjustable loops showed a high stiffness and resistance with a very low elongation after cycling.

Outcomes after bone grafting in patients with and without ACL revision surgery: a retrospective study

BACKGROUND

Current literature is lacking of data regarding functional outcomes in patients following bone tunnel grafting with or without revision anterior cruciate ligament (ACL) reconstruction. Therefore, the aim of the present study was to evaluate the clinical outcome in patients with (RACL) or without revision ACL reconstruction (OBG) following bone grafting.

METHODS

Fifty-nine patients (18 female, 41 male) who underwent bone grafting due to recurrent, symptomatic ACL deficiency following ACL reconstruction between 2011 and 2014 were retrospectively analyzed. In 44 patients (mean age: 30,5 ± 8,5 years) a staged revision ACL reconstruction (RACL) was performed after bone grafting. 10 patients (mean age: 33.2 ± 10.3 years) refused to have ACL revision surgery after bone grafting (OBG). Outcome measures included instrumented laxity testing, the International Knee Documentation Committee (IKDC) score, the Knee Injury and Osteoarthritis Outcome Score (KOOS), Lysholm score and Tegner activity scale.

RESULTS

After mean period of 33,9 ± 17.0 months, 54 patients were available for follow up examination. In the RACL group, the Lysholm score was 77,2 ± 15,5 (range 35-100), the mean IKDC subjective knee score was 69,0 ± 13,4 (range 39,1-97,7) and the mean Tegner activity score was 4,1 ± 1,5 (range, 1-9). Similarly, in the OBG group the mean Lysholm score was 72,90 ± 18,7 (range 50-100), the mean IKDC subjective score was 69,3 ± 20,0 (range 44,1-100) and the mean Tegner activity score was 4,6 ± 1,2 (range, 3-6). No significant difference was observed between the two groups. Knee laxity measurements were elevated without revision ACL surgery, however the difference was not significant.

CONCLUSION

Bone tunnel grafting with or without second stage ACL revision surgery showed no significant difference in functional outcome score. Thus, in case of revision ACL instability careful patient selection is necessary and expectations should be discussed openly with the patients.

Comparison of Knee Stability, Strength Deficits, and Functional Score in Primary and Revision Anterior Cruciate Ligament Reconstructed Knees

Comparing to primary surgery, revision ACL reconstruction is more technically demanding and has a higher failure rate. Theoretically, rehabilitation can improve knee function after ACL reconstruction surgery. This study aimed to compare knee stability, strength, and function between primary and revision ACL reconstructed knees. 40 primary and 40 revision ACL reconstruction surgeries were included between April 2013 and May 2016. Patients with revision surgery had a higher anteroposterior translation comparing those with primary reconstruction (median laxity, 2.0 mm vs. 3.0 mm, p = 0.0022). No differences were noted in knee extensor at 60°/sec or 180°/sec (p = 0.308, p = 0.931, respectively) or in flexor muscle strength at 60°/sec or 180°/sec between primary and revision ACL reconstruction knees (p = 0.091, p = 0.343, respectively). There were also no significant differences between functional scores including IKDC score and Lysholm score in primary versus revision surgeries at 12th months after index operation (p = 0.154, p = 0.324, respectively). In conclusion, despite having higher anteroposterior instability, patients with revision ACL reconstruction can have non-inferior outcomes in isokinetic knee strength and function compared to those with primary ACL reconstruction after proper rehabilitation.

Risk Factors and Predictors of Significant Chondral Surface Change From Primary to Revision Anterior Cruciate Ligament Reconstruction: A MOON and MARS Cohort Study

BACKGROUND

Articular cartilage health is an important issue following anterior cruciate ligament (ACL) injury and primary ACL reconstruction. Factors present at the time of primary ACL reconstruction may influence the subsequent progression of articular cartilage damage.

HYPOTHESIS

Larger meniscus resection at primary ACL reconstruction, increased patient age, and increased body mass index (BMI) are associated with increased odds of worsened articular cartilage damage at the time of revision ACL reconstruction.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Subjects who had primary and revision data in the databases of the Multicenter Orthopaedics Outcomes Network (MOON) and Multicenter ACL Revision Study (MARS) were included. Reviewed data included chondral surface status at the time of primary and revision surgery, meniscus status at the time of primary reconstruction, primary reconstruction graft type, time from primary to revision ACL surgery, as well as demographics and Marx activity score at the time of revision. Significant progression of articular cartilage damage was defined in each compartment according to progression on the modified Outerbridge scale (increase ≥1 grade) or >25% enlargement in any area of damage. Logistic regression identified predictors of significant chondral surface change in each compartment from primary to revision surgery.

RESULTS

A total of 134 patients were included, with a median age of 19.5 years at revision surgery. Progression of articular cartilage damage was noted in 34 patients (25.4%) in the lateral compartment, 32 (23.9%) in the medial compartment, and 31 (23.1%) in the patellofemoral compartment. For the lateral compartment, patients who had >33% of the lateral meniscus excised at primary reconstruction had 16.9-times greater odds of progression of articular cartilage injury than those with an intact lateral meniscus ( P < .001). For the medial compartment, patients who had <33% of the medial meniscus excised at the time of the primary reconstruction had 4.8-times greater odds of progression of articular cartilage injury than those with an intact medial meniscus ( P = .02). Odds of significant chondral surface change increased by 5% in the lateral compartment and 6% in the medial compartment for each increased year of age ( P ≤ .02). For the patellofemoral compartment, the use of allograft in primary reconstruction was associated with a 15-fold increased odds of progression of articular cartilage damage relative to a patellar tendon autograft ( P < .001). Each 1-unit increase in BMI at the time of revision surgery was associated with a 10% increase in the odds of progression of articular cartilage damage ( P = .046) in the patellofemoral compartment.

CONCLUSION

Excision of the medial and lateral meniscus at primary ACL reconstruction increases the odds of articular cartilage damage in the corresponding compartment at the time of revision ACL reconstruction. Increased age is a risk factor for deterioration of articular cartilage in both tibiofemoral compartments, while increased BMI and the use of allograft for primary ACL reconstruction are associated with an increased risk of progression in the patellofemoral compartment.

High incidence of partially anatomic tunnel placement in primary single-bundle ACL reconstruction

PURPOSE

The purpose of this study was to evaluate tunnel position and width in failed primary single-bundle (SB) anterior cruciate ligament (ACL) reconstructions. It was hypothesized that both femoral and tibial bone tunnels are frequently malplaced in terms of a partially anatomic position in the setting of failed SB ACL reconstruction.

METHODS

Patients with recurrent instability following isolated SB ACL reconstruction using hamstring tendon autografts, undergoing revision ACL surgery, were retrospectively included. Further inclusion criteria were age >18 years and availability of preoperative computed tomography (CT) scans and radiographs of the affected knee. Patients with multiligamentous instabilities as well as incomplete or poor radiographs were excluded. Tunnel position was evaluated according to the method described by Harner et al. and Stäubli and Rauschning. Tunnel width was determined on CT scans perpendicular to the bone tunnel axis at three different heights of each bone tunnel.

RESULTS

Eighty-two patients met the inclusion criteria and were considered for radiological analysis. Femoral tunnels were graded as anatomic in 60% (49 of 82) of all cases. In the remaining 40% (33/82), 27% of the tunnels were placed partially anatomic and 13% were graded as non-anatomic. Tibial tunnel placement was found to be anatomic in 54% (44/82) of all cases, partially anatomic in 45% and non-anatomic in 1% of the cases. No statistically significant difference between anatomic or partially anatomic tunnel position and tunnel diameter, neither for the femoral nor for the tibial side, was observed (n.s.).

CONCLUSION

The present study demonstrates that there is a high incidence of partially anatomic placed tunnels in failed SB ACL reconstruction. Tunnel width was not associated with tunnel position. Clinically, partially anatomic bone tunnels frequently require a staged procedure with bone grafting and subsequent ACL revision surgery. Thus, surgeons should carefully analyse tunnel position and width preoperatively to properly plan ACL revision surgery.

Clinical Outcomes in Revision Anterior Cruciate Ligament Reconstruction: A Meta-analysis

PURPOSE

The purpose of this meta-analysis was to determine overall objective graft failure rate, failure rate by graft type (allograft vs autograft reconstruction), instrumented laxity, and patient outcome scores following revision anterior cruciate ligament (ACL) reconstruction. Outcomes of interest were collected for all studies meeting the study inclusion criteria, but lower-level studies (level III/IV) were not pooled for quantitative synthesis due to high levels of heterogeneity in these study populations.

METHODS

A comprehensive search strategy was performed to identify studies reporting outcomes of revision ACL reconstruction. The primary outcome reported was graft failure. A meta-analysis comparing rate of failure by graft type was conducted using a random effects model. Studies also reported patient clinical outcome scores, including International Knee Documentation Committee (IKDC), Lysholm, and knee injury and osteoarthritis outcome scores (KOOS) and graft laxity.

RESULTS

Eight studies with 3,021 patients (56% male, 44% female) with an average age of 30 ± 4 years and mean follow-up time of 57 months were included. The overall objective failure rate was 6% (95% confidence interval [CI], 1.8%-12.3%). Mean instrumented laxity as side-to-side difference was 2.5 mm (95% CI, 1.9-3.1 mm). Mean IKDC subjective score was 76.99 (95% CI, 76.64-77.34), mean KOOS symptoms score was 76.73 (95% CI, 75.85-77.61), and mean Lysholm score was 86.18 (95% CI, 79.08-93.28). The proportion of patients with IKDC grade A or B was 85% (95% CI, 77%-91%). When the available data for failure rate were analyzed by graft type, autograft reconstruction had a failure rate of 4.1% (95% CI, 2.0%-6.9%), similar to allograft reconstruction at 3.6% (95% CI, 1.4%-6.7%).

CONCLUSIONS

In this meta-analysis, revision ACL reconstruction had failure rates similar to autograft or allograft reconstruction. Overall outcome scores for revision reconstruction have improved but appear modest when compared with primary ACL reconstruction surgery.

LEVEL OF EVIDENCE

Meta-analysis of Level II studies, Level II.

Does the type of graft affect the outcome of revision anterior cruciate ligament reconstruction? a meta-analysis of 32 studies

AIMS

Our aim was to perform a meta-analysis of the outcomes of revision anterior cruciate ligament (ACL) reconstruction, comparing the use of different types of graft.

MATERIALS AND METHODS

A search was performed of Medline and Pubmed using the terms "Anterior Cruciate Ligament" and "ACL" combined with "revision", "re-operation" and "failure". Only studies that reported the outcome at a minimum follow-up of two years were included. Two authors reviewed the papers, and outcomes were subdivided into autograft and allograft. Autograft was subdivided into hamstring (HS) and bone-patellar tendon-bone (BPTB). Subjective and objective outcome measures were analysed and odds ratios with confidence intervals were calculated.

RESULTS

A total of 32 studies met the inclusion criteria. Five studies used HS autografts, eight reported using BPTB autografts, two used quadriceps tendon autografts and eight used various types. Seven studies reported using allografts, while the two remaining used both BPTB autografts and allografts. Overall, 1192 patients with a mean age of 28.7 years (22.5 to 39) and a mean follow-up of 5.4 years (2.0 to 9.6) were treated with autografts, while 269 patients with a mean age of 28.4 years (25 to 34.6) and a mean follow-up of 4.0 years (2.3 to 6.0) were treated with allografts. Regarding allografts, irradiation with 2.5 mrad was used in two studies while the graft was not irradiated in the seven remaining studies. Reconstructions following the use of autografts had better outcomes than those using allograft with respect to laxity, measured by KT-1000/2000 (MEDmetric Corporation) and the rates of complications and re-operations. Those following the use of allografts had better mean Lysholm and Tegner activity scores compared with autografts. If irradiated allografts were excluded from the analysis, outcomes no longer differed between the use of autografts and allografts. Comparing the types of autograft, all outcomes were similar except for HS grafts which had better International Knee Documentation Committee scores compared with BPTB grafts.

CONCLUSION

Autografts had better outcomes than allografts in revision ACL reconstruction, with lower post-operative laxity and rates of complications and re-operations. However, after excluding irradiated allografts, outcomes were similar between autografts and allografts. Overall, the choice of graft at revision ACL reconstruction should be on an individual basis considering, for instance, the preferred technique of the surgeon, whether a combined reconstruction is required, the type of graft that was previously used, whether the tunnels are enlarged and the availability of allograft. Cite this article: Bone Joint J 2017;99-B:714-23.

Traumatic graft rupture after primary and revision anterior cruciate ligament reconstruction: retrospective analysis of incidence and risk factors in 2915 cases

PURPOSE

To determine incidence and risk factors for traumatic graft rupture following primary and revision anterior cruciate ligament (ACL) reconstruction.

METHODS

All cases of isolated ACL reconstructions (primary or revision) performed at our institution between January 2007 and December 2010 were included. From this group of 2467 primary reconstructions (32.4 ± 12.2 years) and 448 revision reconstructions (33.0 ± 10.4 years), we identified all patients who underwent revision ACL reconstruction following traumatic graft rupture in further course and all patients who underwent contralateral primary ACL reconstruction until January 2014. Age, gender, time from index procedure and graft diameter (for hamstring autografts) were analysed in terms of being a potential risk factor for graft rupture.

RESULTS

Within a follow-up period of 5.0 ± 1.1 years (3.0-7.0), a total of 82 traumatic graft ruptures were identified, resulting in an incidence of 2.8 %. Seventy-three cases were seen following primary reconstructions (3.0 %), and nine cases following revision reconstructions (2.0 %), respectively (n.s.). Age younger than 25 years was identified as a risk factor for both groups (p = 0.001 and p = 0.008; odds ratio 6.0 and 6.4, respectively). In primary reconstruction, male patients had a higher risk of graft rupture compared with females (3.7 vs. 1.6 %; p = 0.005), and the first year after index procedure was associated with a higher risk of graft rupture compared with the following (p < 0.001). Graft diameter did not influence the risk of graft rupture. Incidence of contralateral ACL rupture was 3.1 %, which was not different to the incidence of graft rupture ipsilaterally (n.s.).

CONCLUSION

No statistically significant differences were seen between graft rupture incidence of primary and revision ACL reconstructions. Young age (<25 years) and short time to the index procedure (especially within the first year) were confirmed as risk factors for graft rupture in both groups. Male gender was a risk factor for primary reconstructions. Graft diameter had no influence on graft rupture rates. No difference in incidence of graft rupture compared to ACL rupture on the contralateral side was apparent.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Bone Incorporation of Silicate-Substituted Calcium Phosphate in 2-Stage Revision Anterior Cruciate Ligament Reconstruction: A Histologic and Radiographic Study

PURPOSE

To evaluate the histologic and radiographic outcomes of using silicate-substituted calcium phosphate (Si-CaP) as bone graft substitute for the augmentation of tunnel defects in 2-stage revision anterior cruciate ligament (ACL) reconstruction.

METHODS

Forty patients undergoing 2-stage revision ACL reconstruction were included in a prospective, randomized controlled clinical trial between 2012 and 2015. The inclusion criteria were tunnel diameter of the tibial and/or femoral tunnel of 10 mm or greater after failed ACL reconstruction. Twenty patients received autologous bone from the iliac crest and 20 patients received Si-CaP as a bone graft substitute for tunnel grafting at the first-stage procedure. Punch biopsy specimens of the augmented tunnels were taken at the second-stage procedure, and histologic examination included quantitative analysis of the area of immature bone formation, lamellar bone, and bone marrow. Radiographic analysis included determination of the filling rates of the tunnels on postoperative computed tomography scans.

RESULTS

Forty patients with a mean age of 32 years (standard deviation [SD], 11.0 years) were analyzed. Histologic examination of the tunnels filled with Si-CaP showed that 15% (SD, 14%) of the area was covered with immature bone formation, 41% (SD, 10%) with well-organized lamellar bone, and 44% (SD, 8%) with bone marrow. In the control group (autologous bone), 58% (SD, 3%) of the area was covered with well-organized lamellar bone and 42% (SD, 3%) with bone marrow. Quantitative evaluation of the postoperative computed tomography scans showed a trend of better filling rates in patients with Si-CaP for the tibial tunnel (86% [SD, 17%] vs 78% [SD, 14%]; P = .131). Intraoperatively, Si-CaP was completely integrated into the original bone tunnel providing good stability for tunnel placement and tendon graft fixation comparable to autologous bone.

CONCLUSIONS

Si-CaP as bone graft substitute for tunnel augmentation in 2-stage revision ACL reconstruction shows good histologic, radiographic, and intraoperative integration comparable to autologous bone.

LEVEL OF EVIDENCE

Level I, prospective randomized controlled trial.

Causes of Failure of Anterior Cruciate Ligament Reconstruction and Revision Surgical Strategies

Purpose

Long-term outcomes of anterior cruciate ligament (ACL) reconstruction are good or excellent; however, 0.7%–20% of patients suffer from recurrent instability due to graft failure. The purpose of this paper was to analyse failure aetiology and the possibilities of revision surgical strategies, with a description of our experience. We obtained optimal and good results in most of our patients.

Materials and Methods

We retrospectively reviewed 42 patients who underwent revision surgery (43 revisions) due to relapsing instability after ACL reconstruction between 2006 and 2015. We used allografts in 39 cases and autografts in 4 cases.

Results

The 85.7% of the patients obtained optimal results (normal knee; group A) and the 7.2% obtained good results (nearly normal knee; group B) according to the International Knee Documentation Committee score. The most frequent failure causes were traumatic events, non-anatomic tunnel placement, and lack of graft incorporation.

Conclusions

A correct revision surgery requires accurate patient evaluation and knee imaging. Preoperative planning starts with the identification of the cause of failure of the primary reconstruction. Then, the most suitable procedure should be determined for each case. It is also important to accurately inform the patient of all the complexity of an ACL revision surgery even if it is a procedure with high rates of excellent and good outcomes.

Anterior Cruciate Ligament Revision Surgery: Ipsilateral Quadriceps Versus Contralateral Semitendinosus-Gracilis Autografts

PURPOSE

To evaluate the subjective outcomes, knee stability, and donor-site morbidity after revision ACL reconstruction using either autologous ipsilateral quadriceps tendon or contralateral semitendinosus-gracilis tendon.

METHODS

A sample size calculation suggested that we needed 25 patients in each group to detect equality between both groups. Therefore, we evaluated 30 consecutive patients who underwent an ACL revision surgery with ipsilateral bone-quadriceps tendon grafts and 30 consecutive patients with the contralateral semitendinosus-gracilis grafts between January 2010 and December 2012. Because of follow-up and exclusion criteria, finally 51 patients were evaluated. All patients were followed prospectively for at least 2 years with KT1000 arthrometer testing and the International Knee Documentation Committee (IKDC) objective grading. At the 24-month follow-up, additional clinical scores were evaluated: the Knee Injury Osteoarthritis Outcome Score (KOOS), the Lysholm score, assessing pain during kneeling, and anterior knee pain.

RESULTS

The KT1000 postoperative arthrometer side-to-side difference was 2.0 ± 1.2 mm for the quadriceps group and 3.0 ± 2.9 mm for the semitendinosus-gracilis group. The difference was not statistically significant (P = .461). There was also no difference in the rate of positive pivot-shift tests between groups (P = .661). The Lysholm score was 82.5 ± 18 in the quadriceps group and 73.8 ± 19 in the semitendinosus-gracilis group. The difference was not statistically significant (P = .060). There was also no significant difference in the single KOOS subscores, assessing pain while kneeling and anterior knee pain (included in the KOOS score). No rerupture occurred during follow-up.

CONCLUSIONS

Revision ACL reconstruction using the quadriceps tendon graft showed clinical outcomes similar to those of the contralateral semitendinosus-gracilis graft in terms of knee stability and function. Thus, the bone-quadriceps tendon graft may be a good alternative to the contralateral semitendinosus-gracilis tendon graft for revision ACL reconstruction.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Preparation techniques for all-inside ACL cortical button grafts: a biomechanical study

PURPOSE

Performing all-inside anterior cruciate ligament reconstruction using cortical button fixation, the tendon graft has to be secured in a closed loop with sutures. In the present study, the graft secured with four sutures was compared with two reduced-suture material graft preparation techniques.

METHODS

A bovine tendon graft folded over two adjustable-length loop cortical button devices was secured using the following techniques: 1, four buried-knot sutures; 2, two sutures on the tibial end only; and 3, two sutures on the tibial graft end with additional suspension on the tibial cortical button. Each group consisted of eight specimens and underwent cyclic loading followed by a load-to-failure test.

RESULTS

The least graft elongation after cyclic loading was observed for the graft with four sutures (6.1 ± 0.6 mm), followed by the graft with two sutures and additional suspension (6.3 ± 0.8 mm) and the graft with two sutures (7.0 ± 0.7 mm). The difference in graft elongation between four sutures and only two sutures was significant (P < 0.05). The ultimate failure loads were highest for the graft with two sutures and additional suspension (801 ± 107 N), followed by the graft with four sutures (766 ± 70 N), and the graft with two sutures (699 ± 87 N). No significant (n.s.) differences were observed between the ultimate failure loads in the three groups.

CONCLUSIONS

For the reduction in suture material to two sutures, additional suspension can be used in order to reduce the graft lengthening. Performing a suture-reducing graft can save operating time and costs. However, each of the three all-inside button graft techniques showed considerable graft elongation indicating a risk of graft lengthening in the early postoperative period.

Return-to-Sport Outcomes After Revision Anterior Cruciate Ligament Reconstruction Surgery

BACKGROUND

There are limited and inconsistent data regarding return-to-sport outcomes after revision anterior cruciate ligament reconstruction (ACLR).

HYPOTHESIS

Return-to-sport rates will be lower after revision ACLR when compared with primary ACLR.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The study cohort consisted of 136 eligible patients who had undergone their first revision ACLR between March 2006 and March 2010. Of these, 109 patients (80%) completed a sports activity survey at a mean 5-year follow-up (range, 3-7 years). Follow-up also included the International Knee Documentation Committee (IKDC) subjective form, Marx Activity Scale, and Knee injury and Osteoarthritis Outcome Score-quality of life (KOOS-QOL) form. Operative details were obtained from the clinical record.

RESULTS

After revision ACLR, 46% (95% CI, 37%-55%) of patients returned to their preinjury level of sport, compared with 50% (95% CI, 41%-59%) after the primary reconstruction in the same patients. Of the patients who were not able to return to their preinjury level of sport after primary reconstruction, 33% improved to the point that they were able to do so after revision. Younger patients were more likely to have returned to their same level of sport (58% vs 38%, P < .05), while the rate of return was the same between male and female patients. Those who returned to their preinjury level of sport scored higher Marx (P < .01), KOOS-QOL (P < .001), and IKDC scores (P < .01) than those who did not. Patients with <50% thickness articular cartilage lesions at revision surgery were more likely to have returned to their preinjury level (52% vs 31%, P < .05) and had significantly better Marx (P < .01), KOOS-QOL (P < .01), and IKDC scores (P < .01) at follow-up. The status of the menisci at the time of revision surgery was not associated with rates of return to sport, but patients with an intact medial meniscus had significantly higher KOOS-QOL (P < .05) scores at follow-up.

CONCLUSION

Return-to-sport rates of patients after revision ACLR were similar to those after their primary surgery but were still lower than the reported rates of ACLR patients who did not need revision surgery. Greater chondral pathologic abnormalities at revision surgery were associated with reduced function at follow-up.

Does revision ACL reconstruction measure up to primary surgery? A meta-analysis comparing patient-reported and clinician-reported outcomes, and radiographic results

PURPOSE

To compare patient-reported and clinician-reported outcomes, and radiographic results between patients who had had revision ACL reconstruction and those who had had primary ACL reconstruction.

DESIGN

Systematic review and meta-analysis

DATA SOURCES

The MEDLINE, CINAHL, EMBASE and SPORTDiscus electronic databases were searched on 6 August 2015, using 3 main concepts: (1) revision ACL reconstruction, (2) primary ACL reconstruction and (3) treatment outcomes.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Articles that compared patient-reported or clinician-reported outcomes or radiographic results between patients who had had revision ACL reconstruction and those who had had primary surgery with a minimum of 2 years follow-up were included. The outcomes evaluated were the Lysholm Knee Scoring Scale, objective International Knee Documentation Committee (IKDC) classification, Tegner Activity Scale, side-to-side difference in anterior tibial translation measured with KT-1000/2000 arthrometer, pivot shift test, tibiofemoral osteoarthritis grading on plain radiographs and subsequent knee surgeries.

RESULTS

8 studies (300 revision ACL reconstructions and 413 primary ACL reconstructions) were included in the meta-analysis. Patients who had had revision surgery reported inferior Lysholm Knee Scoring Scale scores (mean difference: 7.8 points), had inferior clinician-reported knee function as assessed with the objective IKDC classification (IKDC category A: 27% vs 57%; IKDC category C or D: 22% vs 8%) and pivot shift test (grade II or III: 7% vs 2%), and more radiographic evidence of tibiofemoral osteoarthritis (50% vs 25%) compared with patients who had had primary surgery.

CONCLUSIONS

Revision ACL reconstruction restored similar anterior-posterior knee laxity compared with primary ACL reconstruction. Patients who had had revision surgery reported inferior Lysholm Knee Scoring Scale scores, had inferior clinician-reported knee function and more radiographic signs of tibiofemoral osteoarthritis compared with patients with primary ACL reconstruction.

Rolled knitted scaffolds based on PLA-pluronic copolymers for anterior cruciate ligament reinforcement: A step by step conception

The aim of this study was to prepare a new knitted scaffold from PLA-Pluronic block copolymers for anterior cruciate ligament reconstruction. The impact of sterilization methods (beta-ray and gamma-ray sterilization) on copolymers was first evaluated in order to take into account the possible damages due to the sterilization process. Beta-ray radiation did not significantly change mechanical properties in contrast to gamma-ray sterilization. It was shown that ACL cells proliferate onto these copolymers, demonstrating their cytocompatibility. Thirdly, in order to study the influence of shaping on mechanical properties, several shapes were created with copolymers yarns: braids, ropes and linear or rolled knitted scaffolds. The rolled knitted scaffold presented interesting mechanical characteristics, similar to native anterior cruciate ligament (ACL) with a 67 MPa Young's Modulus and a stress at failure of 22.5 MPa. These findings suggest that this three dimensional rolled knitted scaffold meet the mechanical properties of ligament tissues and could be suitable as a scaffold for ligament reconstruction. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 735-743, 2017.

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.

Revision anterior cruciate ligament reconstruction: clinical outcome and evidence for return to sport

PURPOSE

An increasing number of patients undergo revision anterior cruciate ligament (ACL) reconstruction, with the intention of returning to sport being a major indication. The aim of this study is to assess the available evidence for clinical improvement and return to sport, to understand the real potential of this procedure in regaining functional activity, and to facilitate improved counselling of patients regarding the expected outcome after revision ACL reconstruction.

METHODS

The search was conducted on the PubMed database. Articles reporting clinical results for revision ACL reconstruction were included. A meta-analysis was performed on return to sport, and results were compared to the literature on primary ACL reconstruction. Other specific clinical outcomes (Lysholm, Tegner, IKDC Objective scores) were also included in the meta-analysis.

RESULTS

Of the 503 identified records, a total of 59 studies involving 5365 patients were included in the qualitative data synthesis. Only 31 articles reported the rate of return to sport. Whereas 73 % of good objective results and satisfactory subjective results were documented, 57 % of patients did not return to the same level of sport activity, significantly inferior to that of a primary procedure.

CONCLUSION

The real potential of revision ACL reconstruction should not be overestimated due to the low number of patients able to return to their previous activity level, significantly inferior with respect to that reported for primary ACL reconstruction. This finding will help physicians in the clinical practice providing realistic expectations to the patients. Future studies should focus on participation-based outcome measures such as return to sport and in strategies to improve the results in terms of return to previous activities after revision ACL reconstruction.

LEVEL OF EVIDENCE

Systematic review and meta-analysis including Level IV studies, Level IV.

Biomechanical comparison of 2 anterior cruciate ligament graft preparation techniques for tibial fixation: adjustable-length loop cortical button or interference screw

BACKGROUND

Cortical button fixation at the femoral side and interference screws within the tibial bone tunnel are widely used for anterior cruciate ligament graft fixation. Using a bone socket instead of a full tunnel allows cortical button fixation on the tibial side as well. If adjustable-length loop cortical button devices are used for femoral and tibial fixation, the tendon graft has to be secured with sutures in a closed tendon loop. The increased distance of fixation points and potential slippage of the tendon strands at the securing sutures might lead to greater risk of postoperative graft elongation when compared with conventional graft preparation with tibial interference screw fixation.

HYPOTHESIS

Compared with an anterior cruciate ligament graft with tibial adjustable-length loop cortical button fixation, a graft with tibial interference screw fixation will show less graft elongation during cyclic loading and lower ultimate failure loads.

STUDY DESIGN

Controlled laboratory study.

METHODS

Grafts with tibial adjustable-length loop cortical button fixation and grafts with tibial interference screw fixation were biomechanically tested in calf tibiae (n = 10 per group). Femoral fixation was equivalent for both groups, using an adjustable-length loop cortical button. Specimens underwent cyclic loading followed by a load-to-failure test.

RESULTS

Grafts with screw fixation showed significantly less initial elongation (cycles 1-5: 1.46 ± 0.26 mm), secondary elongation (cycles 6-1000: 1.87 ± 0.67 mm), and total elongation (cycles 1-1000: 3.33 ± 0.83 mm) in comparison with grafts with button fixation (2.47 ± 0.26, 3.56 ± 0.39, and 6.03 ± 0.61 mm, respectively) (P < .001). While pull-out stiffness was significantly higher for grafts with screw fixation (309.5 ± 33.2 vs 185.6 ± 16.4 N/mm) (P < .001), grafts with button fixation were able to withstand significantly higher ultimate failure loads (908 ± 74 vs 693 ± 119 N) (P < .001).

CONCLUSION

Grafts with tibial adjustable-length loop cortical button fixation resulted in higher graft elongation during cyclic loading and showed higher ultimate failure loads in comparison with conventional graft preparation with tibial interference screw fixation at time zero.

CLINICAL RELEVANCE

The results of this biomechanical study suggest that grafts with tibial interference screw fixation provide better knee stability at time zero because of reduced graft elongation and greater stiffness in comparison with grafts with tibial adjustable-length loop cortical button fixation.

The prevalence of meniscal tears in young athletes undergoing revision anterior cruciate ligament reconstruction

PURPOSE

The purpose of this study was to determine the incidence of meniscal injury, specifically medial meniscal injury, in US Army soldiers undergoing revision anterior cruciate ligament (ACL) reconstruction.

METHODS

A retrospective review was performed of all patients who underwent revision ACL reconstruction from 2002 to 2011 at our institution. A complete chart review was performed to identify the prevalence of meniscal pathology identified at the time of revision ACL surgery. Patient demographic data and meniscal injury patterns were analyzed.

RESULTS

Sixty-seven patients were identified, with a mean age of 28 years. The mean time to revision reconstruction was 67 months. Most patients (64.1%) reported a distinct reinjury. Reinjury was reported as the cause for revision ACL reconstruction in 43 patients. In this subgroup the mean time from reinjury to revision surgery was 13.9 months. Meniscal pathology was identified in 50 patients (74.6%). Medial meniscal tears were noted in 38 patients (56.7%), a rate significantly greater than that previously described (P = .008). Lateral meniscal tears were noted in 26 patients (38.8%), which was similar to previously published data (P = .52).

CONCLUSIONS

The prevalence of meniscal injury at the time of revision ACL reconstruction in active-duty US Army soldiers is nearly identical to that of previously published data looking at a civilian population (74.6% v 74%) in the Multicenter ACL Revision Study (MARS) cohort. However, the incidence of medial meniscal injury was greater in the active-duty population than in the civilian population (56.7% v 40%). The observed increase in the prevalence of medial meniscal pathology is likely multifactorial, relating to the unique demands on young military athletes in both combat and training environments, rate of reinjury, and various delays to treatment after reinjury.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.