Double-bundle versus single-bundle anterior cruciate ligament reconstruction: a prospective randomized study with 5-year results

Double-bundle anterior cruciate ligament reconstruction is superior to single-bundle reconstruction in terms of revision frequency: a study of 22,460 patients from the Swedish National Knee Ligament Register

PURPOSE

Studies comparing single- and double-bundle anterior cruciate ligament (ACL) reconstructions often include a combined analysis of anatomic and non-anatomic techniques. The purpose of this study was to compare the revision rates between single- and double-bundle ACL reconstructions in the Swedish National Knee Ligament Register with regard to surgical variables as determined by the anatomic ACL reconstruction scoring checklist (AARSC).

METHODS

Patients from the Swedish National Knee Ligament Register who underwent either single- or double-bundle ACL reconstruction with hamstring tendon autograft during the period 2007-2014 were included. The follow-up period started with primary ACL reconstruction, and the outcome measure was set as revision surgery. An online questionnaire based on the items of the AARSC was used to determine the surgical technique implemented in the single-bundle procedures. These were organized into subgroups based on surgical variables, and the revision rates were compared with the double-bundle ACL reconstruction. Hazard ratios (HR) with 95% confidence interval (CI) was calculated and adjusted for confounders by Cox regression.

RESULTS

A total of 22,460 patients were included in the study, of which 21,846 were single-bundle and 614 were double-bundle ACL reconstruction. Double-bundle ACL reconstruction had a revision frequency of 2.0% (n = 12) and single-bundle 3.2% (n = 689). Single-bundle reconstruction had an increased risk of revision surgery compared with double-bundle [adjusted HR 1.98 (95% CI 1.12-3.51), p = 0.019]. The subgroup analysis showed a significantly increased risk of revision surgery in patients undergoing single-bundle with anatomic technique using transportal drilling [adjusted HR 2.51 (95% CI 1.39-4.54), p = 0.002] compared with double-bundle ACL reconstruction. Utilizing a more complete anatomic technique according to the AARSC lowered the hazard rate considerably when transportal drilling was performed but still resulted in significantly increased risk of revision surgery compared with double-bundle ACL reconstruction [adjusted HR 1.87 (95% CI 1.04-3.38), p = 0.037].

CONCLUSIONS

Double-bundle ACL reconstruction is associated with a lower risk of revision surgery than single-bundle ACL reconstruction. Single-bundle procedures performed using transportal femoral drilling technique had significantly higher risk of revision surgery compared with double-bundle. However, a reference reconstruction with transportal drilling defined as a more complete anatomic reconstruction reduces the risk of revision surgery considerably.

LEVEL OF EVIDENCE

III.

Tunnel widening in single- versus double-bundle anterior cruciate ligament reconstructed knees

PURPOSE

The consequence of tunnel widening after ACL reconstructions is foremost of importance in case of revision surgery. Tunnel expansion leads to bone loss close to the joint, and additional surgery with bone grafting prior to revision surgery might be necessary. The purpose of the study was to measure widening of the tunnels in single-bundle (SB) and double-bundle (DB) ACL reconstructed knees during the first year after surgery, detected by a novel, semi-automated 3D CT imaging modality. Our hypothesis was that there would be a difference between the initial tunnel size and the size measured one year post-operatively due to the tunnel widening process. Further, the purpose was to evaluate whether there were any differences in the amount of tunnel widening between the two surgical techniques.

METHODS

Twenty patients who underwent DB ACL reconstruction, and 22 patients who underwent SB ACL reconstruction, performed a CT scan of the bony tunnels, during their first days after surgery and one year post-operatively. The CT scans were transformed into 3D CT reconstructions, and the tunnels were measured with the "best-fit cylinder" method, measurements at the level of tunnel aperture and 10.0 mm from the joint line.

RESULTS

All tunnels in the DB and SB ACL reconstructed knees exhibited widening during the first year after the operation (p < 0.001). The SB femoral tunnels showed more widening compared to the DB femoral AM tunnels (1.4 ± 0.9 vs. 0.5 ± 0.6 mm) (p < 0.001), and the SB tibial tunnels widened more compared to the DB tibial PL tunnels (1.0 ± 1.0 vs. 0.5 ± 0.6) (p < 0.043).

CONCLUSION

All tunnels widened during the first year after the ACL reconstruction with a larger amount of widening in the SB tunnels compared to the DB femoral AM tunnels and the DB tibial PL tunnels. This is the first study to detect tunnel widening in DB reconstructed knees through a semi-automated 3D CT imaging modality.

LEVEL OF EVIDENCE

Prospective cohort study, Level III.

Biomechanical comparison of graft structures in anterior cruciate ligament reconstruction

PURPOSE

Double-bundle (DB) anterior cruciate ligament (ACL) reconstruction may offer kinematic restoration superior to anatomic single bundle (SB), but it remains technically challenging. The femoral attachment site has the most effect on ACL graft isometry, so a simplified three-socket (3S) construct which still uses two sockets to cover the femoral ACL attachment is attractive. It was hypothesised that ACL reconstruction using three- and four-socket techniques would more closely restore native knee kinematics compared to anatomic two-socket (SB) surgery.

METHODS

Nine cadaveric knees were used to evaluate the kinematics of ACL-intact, ACL-deficient, anatomic SB, three-socket, and DB arthroscopic ACL reconstructions. Suspensory fixation was used, and grafts were tensioned to match the anterior draw of the intact knee at 20°. A six-degree-of-freedom robotic system measured knee laxity under 90 N anterior tibial force and rotational laxity under 5 N-m torque. Combined moments were applied to simulate the pivot-shift subluxation: 4 N-m internal rotation and 8 N-m valgus.

RESULTS

Significant differences between reconstructions were not found during anterior tibial loading, apart from SB being more lax than DB at 60° flexion. All reconstructions produced comparable laxity to the intact state, apart from SB at 60°. Significant differences between reconstructions were not found at any flexion angle during tibial internal/external applied torques. Under combined loading, DB produced significantly less laxity than SB constructs apart from anterior tibial translation at 0° and internal rotation at 45°. 3S and DB were comparable to the native knee throughout.

CONCLUSION

Although 3S restored laxities to a similar extent to DB, significant superiority over SB surgery was not observed. Although statistically significant differences were found between SB and DB surgery during anterior tibial and simulated pivot-shift loading, both remained similar to the native knee. The clinical relevance is that this study did not support an ACL graft construct more complex than an anatomic single bundle.

Correlation between hip function and knee kinematics evaluated by three-dimensional motion analysis during lateral and medial side-hopping

[Purpose] Kinematic and kinetic characteristics of the limb during side-hopping and hip/knee interaction during this motion have not been clarified. The purposes of this study were to examine the biomechanical parameters of the knee during side hop and analyze its relationship with clinical measurements of hip function. [Subjects and Methods] Eleven male college rugby players were included. A three-dimensional motion analysis system was used to assess motion characteristics of the knee during side hop. In addition, hip range of motion and muscle strength were evaluated. Subsequently, the relationship between knee motion and the clinical parameters of the hip was analyzed. [Results] In the lateral touchdown phase, the knee was positioned in an abducted and externally rotated position, and increasing abduction moment was applied to the knee. An analysis of the interaction between knee motion and hip function showed that range of motion for hip internal rotation was significantly correlated with external rotation angle and external rotation/abduction moments of the knee during the lateral touchdown phase. [Conclusion] Range of motion for hip internal rotation should be taken into consideration for identifying the biomechanical characteristics in the side hop test results.

Single- or Double-Bundle Technique in the Anterior Cruciate Ligament Reconstruction — Current Concepts and Review of the Literature

The treatment for anterior cruciate ligament (ACL) deficient knee consists in its surgical reconstruction. There are several available and validated techniques, but there are still numerous questions to be answered concerning the best approach in terms of stability, functional outcome, and avoiding further damage in the knee. This paper sought to analyze the studies published in the literature comparing the outcomes of ACL restoration with single-bundle versus double-bundle techniques. The results demonstrate that even if biomechanical studies find an increased steadiness with double-bundle ACL reconstruction, there seems to be no clinical or functional benefit compared with single-bundle reconstruction.

[The time-related risk for knee osteoarthritis after ACL injury. Results from a systematic review]

AIM

The aim of this review was to evaluate the time-related risk for knee osteoarthritis in patients after ACL injury.

MATERIALS AND METHODS

The primary search was carried out in different medical databases with the deadline 12.01.2014. The search strategy for the evaluation was [ACL] AND [osteoarthritis] including "all fields". All 1656 title/abstracts were reviewed by two independent researchers who selected 140 papers for full text review. Finally, a total of 21 relevant publications were identified for inclusion in this current paper.

RESULTS

The incidence of knee osteoarthritis rises significantly over time. Two years after injury it was 6.9%, after 5 years 32.2%, after 7 years 36.3%, and after 10 years 79.6%. At the same time, the crude relative risk of OA rises as the time interval since injury increases. The relative risk of OA has already doubled by 2 years after ACL injury). By 7 years it has increased fivefold and compared with OA status at the time of injury it is still increasing significantly after 10 years.

CONCLUSIONS

The ACL injury is a significant risk factor for the development of early-onset secondary knee osteoarthritis. Within 5 years of the injury the knee shows clear signs of osteoarthritis on MRI. However, these lesions are often not associated with any clinical signs. Knee osteoarthritis as a severe disease starts 8 years or later after the injury, when it requires treatment.

Predictors of Revision Surgery After Primary Anterior Cruciate Ligament Reconstruction

Background:

Revision anterior cruciate ligament (ACL) reconstruction surgery occurs in 5% to 15% of individuals undergoing ACL reconstruction. Identifying predictors for revision ACL surgery is of essence in the pursuit of creating adequate prevention programs and to identify individuals at risk for reinjury and revision.

Purpose:

To determine predictors of revision ACL surgery after failed primary ACL reconstruction.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

A total of 251 participants (mean age ± SD, 26.1 ± 9.9 years) who had undergone primary ACL reconstruction 1 to 5 years earlier completed a comprehensive survey to determine predictors of revision ACL surgery at a mean 3.4 ± 1.3 years after the primary ACL reconstruction. Potential predictors that were assessed included subject characteristics (age at the time of surgery, time from injury to surgery, sex, body mass index, preinjury activity level, return to sport status), details of the initial injury (mechanism; concomitant injury to other ligaments, menisci, and cartilage), surgical details of the primary reconstruction (Lachman and pivot shift tests under anesthesia, graft type, femoral drilling technique, reconstruction technique), and postoperative course (length of rehabilitation, complications). Univariate and multivariate logistic regression analyses were performed to identify factors that predicted the need for revision ACL surgery.

Results:

Overall, 21 (8.4%) subjects underwent revision ACL surgery. Univariate analysis showed that younger age at the time of surgery (P = .003), participation in sports at a competitive level (P = .023), and double-bundle ACL reconstruction (P = .024) predicted increased risk of revision ACL surgery. Allograft reconstructions also demonstrated a trend toward greater risk of revision ACL surgery (P = .076). No other variables were significantly associated with revision ACL surgery. Multivariate analysis revealed that revision ACL surgery was only predicted by age at the time of surgery and graft type (autograft vs allograft).

Conclusion:

The overall revision ACL surgery rate after primary unilateral ACL reconstruction was 8.4%. Univariate predictors of revision ACL reconstruction included younger age at the time of surgery, competitive baseline activity level, and double-bundle ACL reconstruction. However, multivariable logistic regression analysis indicated that age and reconstruction performed with allograft were the only independent predictors of revision ACL reconstruction.

A new technique in double-bundle anterior cruciate ligament reconstruction with implant-free tibial fixation

PURPOSE

This case-series outcome study presents a surgical technique for anatomic double-bundle anterior cruciate ligament (ACL) reconstruction with 4-tunnel using two interference screws. There was a 2-year minimum follow-up.

METHODS

From January to December 2009, an ACL 4-tunnel, anatomic, double-bundle reconstruction was performed on 27 patients. Double-strand hamstring tendon grafts were used in each femoral tunnel as well as two interference screws. Tibial fixation was insured through manual tension, by tying non-absorbable sutures on the bone bridge between the two tunnels at 20° of knee flexion. Clinical assessments included the International Knee Documentation Committee (IKDC) and Lysholm knee scores, range of motion (ROM), pivot-shift test, single-leg hop, and quadriceps-hamstrings strength tests using a hand-held dynamometer. Anterior knee laxity was also assessed using a rolimeter. A single examiner performed all testing pre-operatively at 6 months and during the 2-year follow-up.

RESULTS

All patients were assessed during the 2-year follow-up. At that time, 92 % of the patients presented normal anterior laxity (average, 1.3 ± 0.5 mm) and rotational knee stability. No statistical side-to-side difference was found for ROM, muscle strength, single-leg hop, and function (n.s.). All patients presented a normal knee function according to the IKDC and the Lysholm score. In addition, no infection, graft failure, or pain were observed at the harvesting site.

CONCLUSION

The study shows that satisfactory results in relation to knee laxity, function, and strength can be achieved with the implant-free tibial fixation in the ACL double-bundle reconstruction with two interference screws.

LEVEL OF EVIDENCE

Therapeutic case series, Level IV.

Systemic Review of Anatomic Single- Versus Double-Bundle Anterior Cruciate Ligament Reconstruction: Does Femoral Tunnel Drilling Technique Matter?

PURPOSE

To provide an up-to-date assessment of the difference between anatomic double-bundle anterior cruciate ligament (ACL) reconstruction (DB-ACLR) and anatomic single-bundle ACL reconstruction (SB-ACLR). We hypothesized that anatomic SB-ACLR using independent femoral drilling technique would be able to achieve kinematic stability as with anatomic DB-ACLR.

METHODS

A comprehensive Internet search was performed to identify all therapeutic trials of anatomic DB-ACLR versus anatomic SB-ACLR. Only clinical studies of Level I and II evidence were included. The comparative outcomes were instrument-measured anterior laxity, Lachman test, pivot shift, clinical outcomes including objective/subjective International Knee Documentation Committee (IKDC) score, Lysholm score, Tegner activity scale and complication rates of extension/flexion deficits, graft failure, and early osteoarthritis. Subgroup analyses were performed for femoral tunnel drilling techniques including independent drilling and transtibial (TT) drilling.

RESULTS

Twenty-two clinical trials of 2,261 anatomically ACL-reconstructed patients were included in the meta-analysis. Via TT drilling technique, anatomic DB-ACLR led to improved instrument-measured anterior laxity with a standard mean difference (SMD) of -0.42 (95% confidence interval [CI] = -0.81 to -0.02), less rotational instability measured by pivot shift (SMD = 2.76, 95% CI = 1.24 to 6.16), and higher objective IKDC score with odds ratio (OR) of 2.28 (95% CI = 1.19 to 4.36). Via independent drilling technique, anatomic DB-ACLR yielded better pivot shift (SMD = 2.04, 95% CI = 1.36 to 3.05). Anatomic DB-ACLR also revealed statistical significance in subjective IKDC score compared with anatomic SB-ACLR (SMD = 0.27, 95% CI = 0.05 to 0.49).

CONCLUSIONS

Anatomic DB-ACLR showed better anterior and rotational stability and higher objective IKDC score than anatomic SB-ACLR via TT drilling technique. Via independent drilling technique, however, anatomic DB-ACLR only showed superiority of rotational stability. All clinical function outcomes except subjective IKDC score were not significantly different between anatomic DB-ACLR and SB-ACLR.

LEVEL OF EVIDENCE

Level II, meta-analysis of Level I and II studies.

Comparison Between Single- and Double-Bundle Anterior Cruciate Ligament Reconstruction With 6- to 8-Stranded Hamstring Autograft: A Prospective, Randomized Clinical Trial

BACKGROUND

Whether double-bundle (DB) anterior cruciate ligament (ACL) reconstruction with 6- to 8-stranded hamstring autograft (HG) is better than single-bundle (SB) ACL reconstruction remains debatable, as long-term follow-up data are lacking.

PURPOSE

To prospectively investigate and compare the long-term results of DB and SB ACL reconstruction with a 6- to 8-stranded HG.

STUDY DESIGN

Randomized controlled clinical trial;

LEVEL OF EVIDENCE

1.

METHODS

A total of 80 patients with chronic ACL rupture were randomized to SB or DB ACL reconstruction with a 6- to 8-stranded HG. In the SB group, both the semitendinosus tendon (ST) and the gracilis tendon (GT) were prepared in 3 or 4 strands, with a total of 6 to 8 strands. In the DB group, the ST was prepared in 3 or 4 strands used for the anteromedial bundle, and the GT was prepared in the same manner for the posterolateral bundle. Each graft was fixed with an EndoButton, a bioabsorbable interference screw, and a staple. Outcome assessment was performed by a blinded independent observer using International Knee Documentation Committee (IKDC), Tegner, and Lysholm scores, as well as range of motion (ROM), Lachman test, pivot-shift test, KT-2000 arthrometer side-to-side difference, and return-to-sport data.

RESULTS

A total of 68 patients (DB group, 34; SB group, 34) were observed for a mean of 80 months (range, 74-86 months). There were 2 traumatic instability failures and two 5° extension restrictions in the DB group, while no failures or 5° extension restrictions were observed in the SB group. The mean Lysholm, Tegner, and IKDC scores improved significantly in both groups compared with preoperation scores (P < .05). No patient had a positive Lachman test result. No significant differences were found between groups in functional scores, incidence of pivot shift, ROM, Lachman test, KT-2000 arthrometer anterior laxity, or time and level of return to sport.

CONCLUSION

Both SB and DB ACL reconstruction with 6- to 8-stranded HG showed satisfactory results in subjective scores and anteroposterior and rotational stability over a nearly 7-year follow-up; neither technique was superior.

Tibial ACL insertion site length: correlation between preoperative MRI and intra-operative measurements

PURPOSE

This study was undertaken primarily to identify the tibial insertion site length of ruptured ACL fibres in patients undergoing primary ACL reconstruction. A secondary aim was to evaluate the correlation of pre- and intra-operative measurements.

METHODS

In 146 patients undergoing primary ACL reconstruction, a preoperative measurement on MRI of the tibial ACL insertion site length was taken by two raters and then compared with single surgeon's intra-operative measurements using a specialized ruler. Inclusion criteria were primary ACL reconstruction and MRI performed within 3 months prior to surgery on one specific MRI machine at the study centre. Inter-rater and intra-rater reliability based on intra class correlation (ICC) was calculated. Additionally, correlation between preoperative and postoperative measurements and the anthropometric data was assessed using Pearson correlation.

RESULTS

The tibial ACL insertion site had a mean length of 16.6 ± 1.6 mm (11.9-21.0) as measured by MRI, and 16.4 ± 1.6 mm (11.0-20.0) as measured intra-operatively. The ICCs for intra- and inter-rater reliability of the MRI measurements were 0.99 (95 % CI 0.97; 0.99; p < 0.001) and 0.81 (95 % CI 0.75; 0.86; p < 0.001), respectively. Regression analysis demonstrated, after controlling for subject height and weight, that the MRI measurements significantly predicted intra-operative measurement of tibial insertion site length (β = 0.796; R (2)-change 0.77; p < 0.001).

CONCLUSION

Preoperative measurement of the tibial ACL length is possible using MRI and can be a valuable aid in more efficient preoperative planning given the knowledge of expected dimensions of special knee structures.

LEVEL OF EVIDENCE

III.

Bioabsorbable versus metallic interference screws for graft fixation in anterior cruciate ligament reconstruction

BACKGROUND

Anterior cruciate ligament (ACL) tears are frequently treated with surgical reconstruction with grafts, frequently patella tendon or hamstrings. Interference screws are often used to secure the graft in bone tunnels in the femur and tibia. This review examines whether bioabsorbable interference screws give better results than metal interference screws when used for graft fixation in ACL reconstruction.

OBJECTIVES

To assess the effects (benefits and harms) of bioabsorbable versus metallic interference screws for graft fixation in ACL reconstruction.

SEARCH METHODS

We searched the Cochrane Bone, Joint and Muscle Trauma Group Specialised Register, CENTRAL (the Cochrane Library), MEDLINE, Embase, LILACS, trial registers and reference lists of articles. Date of search: January 2016.

SELECTION CRITERIA

We included randomised controlled trials and quasi-randomised trials comparing bioabsorbable with metallic interferences screws in ACL reconstruction. The main outcomes sought were subjective-rated knee function, failure of treatment, and activity level.

DATA COLLECTION AND ANALYSIS

At least two review authors selected eligible trials, independently assessed risk of bias, and cross-checked data. Data were pooled whenever relevant and possible. Requests for further information were sent to the original study authors.

MAIN RESULTS

We included 12 trials (11 randomised and one quasi-randomised) involving a total of 944 participants, and reporting follow-up results for 774. Participants in the 12 trials underwent ACL reconstruction with either hamstring tendon grafts (five trials) or patellar tendon grafts (seven trials). Trials participants were randomly allocated to bioabsorbable or metallic interference screws for graft fixation in both femur and tibia (seven trials); femur only (three trials); tibia only (one trial); location was not reported in the remaining trial. A variety of materials was used for the bioabsorbable screws, Poly-L-lactic acid (PLLA) being the most common. The metallic screws, where reported, were titanium.All trials were at high risk of bias, which invariably included performance bias. Seven trials were at high risk of attrition bias and eight at high risk of reporting bias. The quasi-randomised trial was assessed as being at high risk for selection bias. Based on these study limitations and insufficiency of the available data, we judged the quality of evidence for all outcomes was very low.The majority of the available data for patient-reported knee function was presented as Lysholm scores (0 to 100; higher scores = better function). There was very low quality but consistent evidence of no clinically important differences between the two groups in Lysholm scores at 12 months follow-up (mean difference (MD) -0.08, 95% confidence interval (CI) -1.48 to 1.32; three trials, 168 participants); 24 months (MD 0.35, 95% CI -1.27 to 1.98; three trials, 113 participants) or five or more years follow-up (MD 1.23, 95% CI -2.00 to 4.47; two trials, 71 participants). This lack of between-group differences was also reported for Lysholm scores in several trials that did not provide sufficient data for pooling as well as for other self-reported knee function scores reported in several trials.Treatment failure was represented by the summed data for implant breakage during surgery and major postoperative complications (implant failure, graft rupture, symptomatic foreign body reactions, effusion and treated arthrofibrosis and related conditions) that were usually described in the trial reports as requiring further substantive treatment. There is very low-quality evidence of greater treatment failure in the bioabsorbable screw group (60/451 versus 29/434; risk ratio (RR) 1.94 favouring metallic screw fixation, 95% CI 1.29 to 2.93; 885 participants, 11 studies). In a population with an assumed risk (based on the median control group risk) of 56 participants per 1000 having treatment failure after metallic screw fixation, this equates to 53 more (95% CI 17 to 108 more) per 1000 participants having treatment failure after bioabsorbable screw fixation. All 16 intraoperative complications in the bioabsorbable screw group were implant breakages upon screw insertion. Treatment failure defined as postoperative complications only still favoured the metallic screw group but the 95% CI also included the potential for a greater risk of treatment failure after metallic screw fixation: 44/451 versus 29/434; RR 1.44, 95% CI 0.93 to 2.23. Based on the assumed risk of 56 participants per 1000 having postoperative treatment failure after metallic screw fixation, this equates to 25 more (95% CI 4 fewer and 69 more) per 1000 participants having this outcome after bioabsorbable screw fixation.There was very low-quality evidence of very similar activity levels in the two groups at 12 and 24 months follow-up measured via the Tegner score (0 to 10; higher scores = greater activity): 12 months (MD 0.08, 95% CI -0.39 to 0.55; 122 participants, two studies); 24 months (MD 0.01, 95% CI -0.54 to 0.57; 72 participants, two studies).

AUTHORS' CONCLUSIONS

There is very low-quality evidence of no difference in self-reported knee function and levels of activity between bioabsorbable and metallic interference screws for graft fixation in ACL reconstruction. There is very low-quality evidence that bioabsorbable screws may be associated with more overall treatment failures, including implant breakage during surgery. Further research does not appear to be a priority, but if undertaken, should also examine costs.

Anatomic Oblong Double Bundle Anterior Cruciate Ligament Reconstruction

Double-bundle anterior cruciate ligament (ACL) reconstruction using hamstring tendon grafts is a standard procedure for ACL injury. However, its clinical effectiveness is not always satisfactory. One cause of this was problems with the graft-tunnel healing of the posterolateral bundle (PLB) on the femur. To solve this problem, we devised a new anatomic ACL reconstruction technique to improve the graft-tunnel healing of the femoral PLB by using a single-bundle with one bone tunnel on the femoral side and a double-bundle on the tibial side. We have performed 40 procedures with excellent results and no cases of intra- or postoperative complication. This procedure can help improve the graft-tunnel healing around the femoral bone tunnel aperture for the PLB.

Medial unicompartmental knee arthroplasty in the ACL-deficient knee

Symptomatic osteoarthritis (OA) of the knee develops often in association with anterior cruciate ligament (ACL) deficiency. Two distinct pathologies should be recognised while considering treatment options in patients with end-stage medial compartment OA and ACL deficiency. Patients with primary ACL deficiency (usually traumatic ACL rupture) can develop secondary OA (typically presenting with symptoms of instability and pain) and these patients are typically young and active. Patients with primary end stage medial compartment OA can develop secondary ACL deficiency (usually degenerate ACL rupture) and these patients tend to be older. Treatment options in either of these patient groups include arthroscopic debridement, reconstruction of the ACL, high tibial osteotomy (HTO) with or without ACL reconstruction, unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). General opinion is that a functionally intact ACL is a fundamental prerequisite to perform a UKA. This is because previous reports showed higher failure rates when ACL was deficient, probably secondary to wear and tibial loosening. Nevertheless in some cases of ACL deficiency with end-stage medial compartment OA, UKA has been performed in isolation and recent papers confirm good short- to mid-term outcome without increased risk of implant failure. Shorter hospital stay, fewer blood transfusions, faster recovery and significantly lower risk of developing major complications like death, myocardial infarction, stroke, deep vein thrombosis (as compared to TKA) make the UKA an attractive option, especially in the older patients. On the other hand, younger patients with higher functional demands are likely to benefit from a simultaneous or staged ACL reconstruction in addition to UKA to regain knee stability. These procedures tend to be technically demanding. The main aim of this review was to provide a synopsis of the existing literature and outline an evidence-based treatment algorithm.

Comparison of Anatomic Double- and Single-Bundle Techniques for Anterior Cruciate Ligament Reconstruction Using Hamstring Tendon Autografts: A Prospective Randomized Study With 5-Year Clinical and Radiographic Follow-up

BACKGROUND

The aim of this prospective randomized study was to compare the outcomes of the anatomic double-bundle (DB) and anatomic single-bundle (SB) techniques 5 years after anterior cruciate ligament (ACL) reconstruction. Since more effective restoration of rotational laxity is considered the main advantage of the DB technique, the pivot-shift test was the primary outcome variable of the study.

HYPOTHESIS

Double-bundle ACL reconstruction will result in a better outcome in terms of the pivot-shift test.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 1.

METHODS

A total of 105 patients (33 women, 72 men; median age, 27 years; range, 18-52 years) were randomized and underwent ACL reconstruction (DB group, n = 53; SB group, n = 52). All reconstructions were performed anatomically by identifying the ACL footprints, using the anteromedial portal for the femoral tunnel drilling, and utilizing interference screw for tibial and femoral fixation. A single blinded observer examined the patients preoperatively and at follow-up (median, 64 months; range, 55-75 months). Multiple subjective and objective clinical evaluation tests and radiographic assessments of osteoarthritis (OA) were performed using the Ahlbäck, Kellgren-Lawrence, and Fairbank grading systems at 6 weeks postoperatively and at the final follow-up evaluation.

RESULTS

Preoperatively, no differences were found between the study groups, apart from the preinjury Tegner activity level, which was lower in the DB group (SB: mean, 7.8 [range, 3-9]; DB: mean, 7.3 [range, 0-9]; P = .02). Eighty-seven patients (83%) were available for examination at the 5-year follow-up. Statistical differences could not be found between the groups in terms of the pivot-shift test, KT-1000 arthrometer laxity measurements, manual Lachman test, single-legged-hop test, square-hop test, range of motion, Lysholm knee scoring scale, Tegner activity scale, or Knee injury and Osteoarthritis Outcome Score. Correspondingly, no differences were found between the groups regarding the presence of OA at follow-up. However, a significant increase of OA was found within the DB group at the 5-year follow-up. Both groups improved at follow-up compared with the preoperative assessment in terms of the laxity tests, hop tests, and scoring scales.

CONCLUSION

At the 5-year follow-up of an unselected group of patients, anatomic DB reconstruction was not superior to anatomic SB reconstruction in terms of the pivot-shift test.

Conventional over-the-top-aiming devices with short offset fail to hit the center of the human femoral ACL footprint in medial portal technique, whereas medial-portal-aiming devices with larger offset hit the center reliably

INTRODUCTION

Aim of this study was to investigate the accuracy of a conventional over-the-top-guide (OTG) with a typically short offset to hit the center of the native femoral ACL footprint through the anteromedial portal in comparison to a specific medial-portal-aimer (MPA) with larger offset.

MATERIALS AND METHODS

In 20 matched human cadaveric knees, insertion sites of the ACL were marked in medial arthrotomy. An OTG with an offset of 5.5 mm, respectively, the MPA with 9 mm offset was used in a medial portal approach to locate the center of a single bundle ACL reconstruction tunnel with k-wires. Distances from the footprint center, the OTG drilling and the MPA drilling to the roof of the intercondylar notch and to the deep cartilage margin were determined. After positioning of radiological markers, radiographic analysis was performed according to the quadrant technique as described by Bernard and Hertel.

RESULTS

The distance from ACL origin to the roof of the notch was 10.3 (±2.1) mm, in the OTG group 6.7 (±1.5) mm and in the MPA group 9.6 (±1.9) mm. The distance to the deep cartilage margin was 9.5 (±1.7) mm from ACL origin, 4.8 (±1.3) mm with OTG and 8.7 (±1.4) mm with MPA. There were statistically significant differences between the distances of the footprint center and the OTG group after measuring and also after radiographic analysis (p < 0.0001). Using the MPA, no significant different distances in comparison to the anatomical ACL center were found (p > 0.0001). There was an increased risk for femoral blow (9/10 vs. 0/10) in the OTG group after overdrilling with a 9 mm drill.

CONCLUSION

Short (5.5 mm) offset femoral aiming devices fail to locate the native ACL footprint center in medial portal approach with an increased risk for femoral blowout when overdrilling. The special medial-portal-aiming device with 9 mm offset hit the center reliably.

Prospective Randomized Study of Objective and Subjective Clinical Results Between Double-Bundle and Single-Bundle Anterior Cruciate Ligament Reconstruction

BACKGROUND

There is controversy as to whether double-bundle anterior cruciate ligament (ACL) reconstruction with hamstring tendon graft (DB-HT) or single-bundle ACL reconstruction with patellar tendon graft (SB-PT) obtains the best clinical outcomes.

PURPOSE

To compare the short-term clinical outcomes of DB-HT with those of rectangular-tunnel SB-PT (RTSB-PT) at 2-year follow-up and to identify the factors that affect subjective knee functional score.

STUDY DESIGN

Randomized controlled trial. Level of evidence, 1.

METHODS

Sixty-three male patients (mean age, 26.1 years) and 87 female patients (mean age, 25.8 years) were included in this study and were randomly distributed to either the DB-HT (n = 76) or RTSB-PT (n = 74) group. Clinical outcomes (knee flexion range of motion [ROM], heel-height difference, side-to-side difference in anterior laxity, rotational laxity, and Tegner activity score) were compared between the DB-HT and RTSB-PT groups, and examination of factors affecting subjective outcomes (Knee Injury and Osteoarthritis and Outcome Score [KOOS] results) was performed by multiple linear regression analysis.

RESULTS

Fourteen patients (9 DB-HT, 5 RTSB-PT) had secondary ACL injury within 2 years after primary ACL reconstruction and were excluded from analysis. In the examination of 136 patients at the 24-month follow-up, there was no significant difference between the 2 groups in clinical or subjective outcomes. The normalized knee extensor strength of the RTSB-PT group showed negative surgical technique effect in the early postoperative phase (P = .005), but there was no significant difference between the 2 groups at the 24-month follow-up (P = .114). There was no significant difference in change of normalized knee flexor strength between the 2 groups (P = .493). Age, sex, body mass index (BMI), and presence of meniscus injury were the factors that affected KOOS subscale scores.

CONCLUSION

In this prospective randomized controlled study, there was no significant difference in the incidence of secondary ACL injury and no difference in objective or subjective outcomes between the DB-HT and RTSB-PT reconstruction at 24-month follow-up. Age, sex, presence of meniscus injury, and BMI affected subjective KOOS subscale scores, while surgical technique did not.

Reruptures, Reinjuries, and Revisions at a Minimum 2-Year Follow-up: A Randomized Clinical Trial Comparing 3 Graft Types for ACL Reconstruction

OBJECTIVE

To evaluate the predictive factors for traumatic rerupture, reinjury, and atraumatic graft failure of anterior cruciate ligament (ACL) reconstruction at a minimum 2-year follow-up.

DESIGN

Double-blind randomized clinical trial (RCT) with intraoperative computer-generated allocation.

SETTING

University-based orthopedic referral practice.

PATIENTS

Three hundred thirty patients with isolated ACL deficiency were equally randomized to (1) patellar tendon (PT; mean, 29.2 years), (2) quadruple-stranded hamstring tendon (HT; mean, 29.0 years), and (3) double bundle using HT (DB; mean, 28.8 years). Three hundred twenty-two patients completed 2-year follow-up.

INTERVENTIONS

Anatomically positioned primary ACL reconstruction with PT, HT, and DB autografts.

MAIN OUTCOME MEASURES

Proportions of complete traumatic reruptures, traumatic reinjuries (complete reruptures and partial tears), atraumatic graft failures, and contralateral ACL tears. Logistic regression assessed 5 a priori determined independent predictors: chronicity, graft type, age, sex, and Tegner level.

RESULTS

More complete traumatic reruptures occurred in the HT and DB groups: PT = 3; HT = 7; DB = 7 (P = 0.37). Traumatic reinjuries statistically favored PT reconstructions: (PT = 3; HT = 12; DB = 11; P = 0.05). Atraumatic graft failures were not different: PT = 16; HT = 17; DB = 20 (P = 0.75). Younger age was a significant predictor of complete traumatic reruptures and traumatic reinjuries (P < 0.01). Higher activity level, males, and patients with HT, DB, and acute reconstructions had greater odds of reinjury. None of these factors reached statistical significance. Contralateral ACL tears were not different between groups, but trends suggested that younger females were more likely to have a contralateral ACL tear.

CONCLUSIONS

More traumatic reinjuries occurred with HT and DB grafts. Younger age was a predictor of complete traumatic rerupture and traumatic reinjury, irrespective of graft type.

LEVEL OF EVIDENCE

Level 1 (Therapeutic Studies).

CLINICAL RELEVANCE

This article describes the complete traumatic graft rerupture, partial traumatic ACL tear, atraumatic graft failure, and contralateral ACL tear rates observed at 2 years postoperatively in a large double-blind RCT comparing PT, single-bundle hamstring, and double-bundle hamstring ACL reconstructions. The odds and predictive factors of traumatic rerupture and reinjury are also evaluated.

A systematic review of single- versus double-bundle ACL reconstruction using the anatomic anterior cruciate ligament reconstruction scoring checklist

PURPOSE

The aim of this systematic review was to apply the anatomic ACL reconstruction scoring checklist (AARSC) and to evaluate the degree to which clinical studies comparing single-bundle (SB) and double-bundle (DB) ACL reconstructions are anatomic.

METHODS

A systematic electronic search was performed using the databases PubMed (MEDLINE), EMBASE and Cochrane Library. Studies published from January 1995 to January 2014 comparing SB and DB ACL reconstructions with clinical outcome measurements were included. The items from the AARSC were recorded for both the SB and DB groups in each study.

RESULTS

Eight-thousand nine-hundred and ninety-four studies were analysed, 77 were included. Randomized clinical trials (29; 38%) and prospective comparative studies (29; 38%) were the most frequent study type. Most studies were published in 2011 (19; 25%). The most commonly reported items for both SB and DB groups were as follows: graft type (152; 99%), femoral and tibial fixation method (149; 97% respectively), knee flexion angle during graft tensioning (124; 8%) and placement of the tibial tunnel at the ACL insertion site (101; 66%). The highest level of documentation used for ACL tunnel position for both groups was often one dimensional, e.g. drawing, operative notes or o'clock reference. The DB reconstruction was in general more thoroughly reported. The means for the AARSC were 6.9 ± 2.8 for the SB group and 8.3 ± 2.8 for the DB group. Both means were below a proposed required minimum score of 10 for anatomic ACL reconstruction.

CONCLUSIONS

There was substantial underreporting of surgical data for both the SB and DB groups in clinical studies. This underreporting creates difficulties when analysing, comparing and pooling results of scientific studies on this subject.

Anatomical "C"-shaped double-bundle versus single-bundle anterior cruciate ligament reconstruction in pre-adolescent children with open growth plates

PURPOSE

To analyse the clinical, rotational and radiological (MRI) results of paediatric anatomical "C-shaped" double-bundle (DB) anterior cruciate ligament (ACL) reconstruction with anteromedial and posteromedial bundle compared to single-bundle (SB) ACL reconstruction.

METHODS

Between 2008 and 2014, 57 consecutive patients received a paediatric ACL reconstruction with open physis and were allocated into two groups, according to the surgical procedure. Transepiphyseal SB technique was used until 2012 and DB consecutively thereafter. Follow-up consisted of a clinical evaluation with assessment of the International Knee Documentation Committee (IKDC) form, the Lysholm knee score, Tegner activity score, KT-1000 arthrometer evaluation, VAS Scores for satisfaction, MRI and testing of rotational stability using a robotic system.

RESULTS

The mean time from ACL reconstruction to follow-up was 48.1 ± 15.8 in the SB group (n = 17) and 23.1 ± 13.2 in the DB group (n = 16; p < 0.001). No differences were found in the subjective scores. Biomechanically, there were significant differences identified in the KT-1000 (p < 0.03) and total tibial axial rotation (p < 0.04) when evaluating the reconstructed knee only. Ten of 17 (59%) of the SB patients had a Joint Play Area within the acceptable range of the median healthy knee value compared to 100 % in the DB group. Decreased patient satisfaction was associated with increased total tibial axial rotation. No growth disturbance was observed. Overall, 98% of patients were reached and either examined or interviewed. Re-rupture rate was 3 of 21 (14.3%) for DB and 9 of 35 (25.7%) for SB. All but one re-ruptures (92%) happened in the first 16 postoperative months independent of technique.

CONCLUSIONS

The re-rupture rate after pre-adolescent ACL reconstruction is too high both historically and in this mixed cohort. Anatomical transepiphyseal DB ACL reconstruction with open physis may result in a reduction in this re-rupture rate, which may be related to a tighter control of the Joint Play Area. While subjective clinical results were similar between SB and DB, decreased patient satisfaction was associated with increased total tibial axial rotation in the entire cohort. Despite the need for two transepiphyseal tunnels in the DB technique, there did not appear to be an increased risk in growth plate disturbance. Transepiphyseal DB ACL reconstruction appears to be a reasonable alternative to current techniques in pre-adolescent children with an ACL rupture.

LEVEL OF EVIDENCE

IV.

Clinical outcome after UKA and HTO in ACL deficiency: a systematic review

PURPOSE

In the treatment of medial osteoarthritis secondary to anterior cruciate ligament (ACL) injury there is no consensus about optimum treatment, with both high tibial osteotomy (HTO) and unicompartmental knee arthroplasty (UKA) being viable options. The aim of this review was to compare the outcomes of these treatments, both with or without ACL reconstruction.

METHODS

EMBASE, MEDLINE and the Clinical Trials Registers were searched to identify relevant studies. Studies meeting pre-defined inclusion criteria were assessed independently by two researchers for methodological quality and data extracted.

RESULTS

Twenty-six studies involving 771 patients were identified for inclusion. No randomized controlled trials were identified. Seventeen studies reported outcomes following HTO and nine studies reported outcomes following UKA. HTO patients were significantly younger than those receiving UKA, and ACL reconstruction patients were younger than non-reconstructed patients. Treatment with HTO ACL reconstruction had the lowest revision rate (0.62/100 observed component years) but the highest rate of complications (4.61/100 observed component years). Too little data were available to test for differences in outcome between different surgical techniques or prosthesis designs.

CONCLUSIONS

Limited conclusions about the optimum treatment can be made due to the absence of controlled trials. In patients treated with HTO ACL reconstruction, the high complication rate likely outweighs its minimally superior survival. Outcomes following UKA ACL reconstruction are similar to outcomes for UKA in the ACL intact knee without any increase in complications. As such in patients meeting indications for UKA, UKA ACL reconstruction should be performed with further work required to identify the optimum treatment in other patient groups.

LEVEL OF EVIDENCE

IV.

Comparison of Knee Kinematics After Single-Bundle Anterior Cruciate Ligament Reconstruction via the Medial Portal Technique With a Central Femoral Tunnel and an Eccentric Femoral Tunnel and After Anatomic Double-Bundle Reconstruction: A Human Cadaveric Study

BACKGROUND

Anatomic femoral tunnel placement in anterior cruciate ligament (ACL) reconstruction is considered to be a key to good primary stability of the knee. There is still no consensus on whether a centrally placed single bundle in the anatomical femoral footprint can compare with anatomic double-bundle (DB) reconstruction.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine knee kinematics after single-bundle ACL reconstruction via the medial portal technique using 2 different femoral tunnel positions and to compare results with those of the anatomic DB technique. The hypotheses were that (1) single-bundle reconstruction using the medial portal technique with a centrally placed femoral tunnel relative to the native footprint (SB-central technique) would more closely restore intact knee kinematics compared with the same reconstruction technique with an eccentric femoral tunnel drilled in the anteromedial bundle footprint (SB-AM technique) and (2) DB reconstruction would result in superior kinematics compared with the SB-central technique.

STUDY DESIGN

Controlled laboratory study.

METHODS

Knee kinematics was examined in 10 fresh-frozen human cadaveric knees using a robotic/universal force-moment sensor system. Kinematics in simulated pivot-shift and 134-N anterior tibial loading tests were determined in different conditions within the same specimen: (1) intact ACL, (2) deficient ACL, (3) SB-AM, (4) SB-central, and (5) DB.

RESULTS

All reconstruction techniques significantly reduced anterior tibial translation (ATT) compared with a deficient ACL at 0°, 15°, 30°, 60°, and 90° in the anterior tibial loading test (P < .01, repeated-measures analysis of variance) and at 0°, 15°, and 30° in the simulated pivot-shift test (P < .001). There were no significant differences in the SB-central group and the DB group compared with the intact ACL. Reconstruction in the SB-AM group resulted in significantly increased ATT compared with the intact ACL in near-to-extension angles in both tests (0°, 15°, and 30°; P < .01). SB-central and DB reconstructions both resulted in significantly reduced ATT, in some tests at ≤30°, compared with SB-AM reconstruction (P < .05). No significant differences between the SB-central and DB groups were found (P > .05).

CONCLUSION

The SB-central technique restored intact knee kinematics more closely than did SB-AM reconstruction at time zero. There were no differences in knee kinematics between the DB and SB-central techniques.

CLINICAL RELEVANCE

Anatomic single-bundle ACL reconstruction provides similar knee kinematics as anatomic double-bundle reconstruction.

Anterior cruciate ligament reconstruction and cartilage contact forces--A 3D computational simulation

BACKGROUND

Clinical outcome studies showed a high incidence of knee osteoarthritis after anterior cruciate ligament reconstruction. Abnormal joint kinematics and loading conditions were assumed as risking factors. However, little is known on cartilage contact forces after the surgery.

METHODS

A validated computational model was used to simulate anatomic and transtibial single-bundle anterior cruciate ligament reconstructions. Two graft fixation angles (0° and 30°) were simulated for each reconstruction. Biomechanics of the knee was investigated in intact, anterior cruciate ligament deficient and reconstructed conditions when the knee was subjected to 134 N anterior load and 400 N quadriceps load at 0°, 30°, 60° and 90° of flexion. The tibial translation and rotation, graft forces, medial and lateral contact forces were calculated.

FINDINGS

When the graft was fixed at 0°, the anatomic reconstruction resulted in slightly larger lateral contact force at 0° compared to the intact knee while the transtibial technique led to higher contact force at both 0° and 30° under the muscle load. When graft was fixed at 30°, the anatomic reconstruction overstrained the knee at 0° with larger contact forces, while the transtibial technique resulted in slightly larger contact forces at 30°.

INTERPRETATION

This study suggests that neither the anatomic nor the transtibial reconstruction can consistently restore normal knee biomechanics at different flexion angles. The anatomic reconstruction may better restore anteroposterior stability and contact force with the graft fixed at 0°. The transtibial technique may better restore knee anteroposterior stability and articular contact force with the graft fixed at 30° of flexion.

Radiographic landmarks for surgical reconstruction of the anterolateral ligament of the knee

PURPOSE

To determine the radiographic landmarks of the anterolateral ligament (ALL) on the femur and tibia to assist in intraoperative graft placement during ALL reconstruction.

METHODS

The footprints of the ALL, fibular collateral ligament (FCL), popliteus insertion, lateral gastrocnemius insertion, and Gerdy's tubercle were isolated and centrally marked with tantalum beads in thirteen fresh-frozen cadaveric knees. Measurements were taken from the true lateral fluoroscopic images. On the femur, the mean distances from the ALL origin to the FCL origin and from the ALL origin to the popliteus insertion were measured. On the tibia, the mean distances from the ALL insertion to Gerdy's tubercle and from the ALL insertion to the lateral tibial plateau were measured. Furthermore, radiographic descriptions of the ALL origin and insertion were developed.

RESULTS

The ALL origin on the femur averaged 3.3 ± 1.5 mm anterior-distal to the FCL origin in one anatomical variant and 5.4 ± 1.4 mm posterior-proximal to the FCL origin in a second variant. The ALL origin was 9.9 ± 2.7 mm from the popliteus insertion. The ALL origin is described as overlying the posterior femoral cortical line, between Blumensaat's line and a line from the posterior condylar articular edge parallel to Blumensaat's line. The ALL insertion on the tibia averaged 24.7 ± 4.5 mm posterior to Gerdy's tubercle and 11.5 ± 2.9 mm distal to the lateral tibial plateau. The tibial ALL insertion is described between the posterior tibial cortical line and a parallel line drawn down from the apex of the tibial spine, and overlying a line drawn perpendicular to the posterior tibial cortical line starting from the apex of the posterior tibial condyles.

CONCLUSIONS

Using direct lateral fluoroscopy, radiographic landmarks of the ALL origin and insertion have been described.

High Variability in Outcome Reporting Patterns in High-Impact ACL Literature

BACKGROUND

ACL (anterior cruciate ligament) reconstruction is one of the most commonly performed and studied procedures in modern sports medicine. A multitude of objective and subjective patient outcome measures exists; however, nonstandardized reporting patterns of these metrics may create challenges in objectively analyzing pooled results from different studies. The goal of this study was to document the variability in outcome reporting patterns in high-impact orthopaedic studies of ACL reconstruction.

METHODS

All clinical studies pertaining to ACL reconstruction in four high-impact-factor orthopaedic journals over a five-year period were reviewed. Biomechanical, basic science, and imaging studies were excluded, as were studies with fewer than fifty patients, yielding 119 studies for review. Incorporation of various objective and subjective outcomes was noted for each study.

RESULTS

Substantial variability in reporting of both objective and subjective measures was noted in the study cohort. Although a majority of studies reported instrumented laxity findings, there was substantial variability in the type and method of laxity reporting. Most other objective outcomes, including range of motion, strength, and complications, were reported in <50% of all studies. Return to pre-injury level of activity was infrequently reported (24% of studies), as were patient satisfaction and pain assessment following surgery (8% and 13%, respectively). Of the patient-reported outcomes, the International Knee Documentation Committee (IKDC), Lysholm, and Tegner scores were most often reported (71%, 63%, and 42%, respectively).

CONCLUSIONS

Substantial variability in outcome reporting patterns exists among high-impact studies of ACL reconstruction. Such variability may create challenges in interpreting results and pooling them across different studies.

Behavior of the anterolateral structures of the knee during internal rotation

INTRODUCTION

Since the recent descriptions of the anterolateral ligament (ALL), the role played by the anterolateral peripheral structures in the rotational control of the knee is again being debated. The objective of this study was to identify the structures during internal tibial rotation and then to define their anatomical characteristics. We hypothesized that internal rotation would tighten several anatomical formations, both superficial and deep, with the ALL one part of these structures.

MATERIAL AND METHODS

Nine fresh-frozen cadaver knee specimens were studied. The anterolateral structures tightened were identified from superficial to deep at 30° of flexion. Each was selectively dissected, identifying its insertions and orientations, and measuring its size. The length variations of the ALL during internal tibial rotation were measured by applying a 30-N force using a dynamometric torque wrench at the tibiofibular mortise.

RESULTS

The superficial structures tightened were the iliotibial tract and the Kaplan fibers. In internal tibial rotation, the Kaplan fibers held the iliotibial tract against the lateral epicondyle, allowing it to play the role of a stabilizing ligament. The Kaplan fibers were 73.11±19.09mm long (range, 63-82mm) and at their femoral insertion they were 12.1±1.61mm wide (range, 10-15mm). The deep structures tightened covered a triangular area including the ALL and the anterolateral capsule. The ALL was 39.11±3.4mm long (range, 35-46mm) in neutral rotation and 49.88±5.3mm long (range, 42-58mm) in internal rotation (p<0.005). Its femoral insertion area was narrow at 5.27±1.06mm (range, 3.5-7mm) and was mainly proximal and posterior at the lateral epicondyle. Its tibial insertion zone was wide, with a clearly differentiated anterior limit but a posterior limit confused with the joint capsule. In the vertical plane, this insertion was located 6.44±2.37mm (range, 2-9) below the joint space.

DISCUSSION

This study demonstrates two distinct anterolateral tissue planes tightened during internal rotation of the tibia: a superficial plane represented by the iliotibial tract and the Kaplan fibers, which acts as a ligament structure, and a deep plane represented by a triangular capsular ligament complex within which the ALL and the anterolateral capsule are recruited.

LEVEL OF EVIDENCE

Descriptive cadaver study IV.

A Randomized Clinical Trial Comparing Patellar Tendon, Hamstring Tendon, and Double-Bundle ACL Reconstructions: Patient-Reported and Clinical Outcomes at a Minimal 2-Year Follow-up

OBJECTIVE

To compare 3 anatomically positioned autografts for anterior cruciate ligament (ACL) reconstruction, by measuring patient-reported disease-specific quality of life at 2 years postoperatively.

DESIGN

Double-blinded, randomized clinical trial with intraoperative computer-generated treatment allocation. Patients and an independent trained evaluator were blinded.

SETTING

University-based orthopedic referral practice.

PATIENTS

Three hundred thirty patients (14-50 years; 183 male patients) with isolated ACL deficiency were equally randomized to: (1) patellar tendon, PT: 28.7 years (SD = 9.7); (2) quadruple-stranded hamstring tendon, HT: 28.5 years (SD = 9.9); and (3) double bundle using HT, DB: 28.3 years (SD = 9.8); 322 patients completed 2-year follow-up.

INTERVENTION

Anterior cruciate ligament reconstruction using PT, HT, or DB autografts.

MAIN OUTCOME MEASURES

Measured at baseline, 1 and 2 years postoperatively-primary: anterior cruciate ligament quality-of-life scores; secondary: International Knee Documentation Committee (IKDC) scores, KT-1000 arthrometer, pivot shift, range of motion, Tegner activity, Cincinnati Occupational Scale, and single-leg hop. Proportions of correct graft type guesses by the patients and evaluator assessed blinding effectiveness.

RESULTS

Baseline characteristics were not different. Anterior cruciate ligament quality-of-life scores increased over time for all groups (P = 0.001) but were not different at 2 years (P = 0.591): PT = 84.6 (SD = 16.6, 95% confidence interval [CI] = 81.4-87.8), HT = 82.5 (SD = 17.7, 95% CI = 79.2-85.9), and DB = 82.4 (SD = 17.5, 95% CI = 79.1-85.7). Two-year KT-1000 side-to-side differences (PT = 1.86 mm; HT = 2.97 mm; DB = 2.65 mm) were statistically significant between PT-HT (P = 0.002) and PT-DB (P = 0.044). The remaining secondary outcomes were not statistically different. Correct graft type guesses occurred 51% of the time for patients and 46% for the evaluator.

CONCLUSIONS

Two-year disease-specific quality-of-life outcome was not different between the ACL reconstruction techniques. The PT reconstructions had significantly lower side-to-side differences on static stability measures. Patient and evaluator blinding was achieved.

LEVEL OF EVIDENCE

Level 1 (Therapeutic Studies).

CLINICAL RELEVANCE

This high-quality, large, double-blind randomized clinical trial (RCT) addresses the insufficient evidence in the literature comparing PT, single-bundle hamstring, and DB hamstring reconstructions for ACL rupture in adults. In addition to the clinical and functional results, this RCT uniquely reports on the disease-specific, patient-reported quality-of-life outcome at 2 years postoperatively.

Does Double-Bundle Anterior Cruciate Ligament Reconstruction Improve Postoperative Knee Stability Compared With Single-Bundle Techniques? A Systematic Review of Overlapping Meta-analyses

PURPOSE

Multiple meta-analyses of randomized controlled trials, the highest available level of evidence, have been conducted to determine whether double-bundle (DB) or single-bundle (SB) anterior cruciate ligament reconstruction (ACL-R) provides superior clinical outcomes and knee stability; however, results are discordant. The purpose of this study was to conduct a systematic review of meta-analyses comparing SB and DB ACL-R to discern the cause of the discordance and to determine which of these meta-analyses provides the current best available evidence.

METHODS

We evaluated available scientific support for SB as compared with DB ACL-R by systematically reviewing the literature for published meta-analyses. Data on patient clinical outcomes and knee stability (as measured by KT arthrometry and pivot-shift testing) were extracted. Meta-analysis quality was judged using the Oxman-Guyatt and Quality of Reporting of Meta-analyses systems. The Jadad algorithm was then applied to determine which meta-analyses provided the highest level of evidence.

RESULTS

Nine meta-analyses were included, of which 3 included Level I Evidence and 6 included both Level I and Level II Evidence. Most studies found significant differences favoring DB reconstruction on pivot-shift testing, KT arthrometry measurement of anterior tibial translation, and International Knee Documentation Committee objective grading. Most studies detected no significant differences between the 2 techniques in subjective outcome scores (Tegner, Lysholm, and International Knee Documentation Committee subjective), graft failure, or complications. Oxman-Guyatt and Quality of Reporting of Meta-analyses scores varied, with 2 studies exhibiting major flaws (Oxman-Guyatt score <3). After application of the Jadad decision algorithm, 3 concordant high-quality meta-analyses were selected, with each concluding that DB ACL-R provided significantly better knee stability (by KT arthrometry and pivot-shift testing) than SB ACL-R but no advantages in clinical outcomes or risk of graft failure.

CONCLUSIONS

The current best available evidence suggests that DB ACL-R provides better postoperative knee stability than SB ACL-R, whereas clinical outcomes and risk of graft failure are similar between techniques.

LEVEL OF EVIDENCE

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

The Relationship between Anterior Cruciate Ligament Injury and Osteoarthritis of the Knee

Anterior cruciate ligament (ACL) tears are a common injury, particularly in the athletic and youth populations. The known association between ACL injury and subsequent osteoarthritis (OA) of the knee merits a more in-depth understanding of the relationship between the ACL-injured knee and osteoarthritis. ACL injury, especially with concomitant meniscal or other ligamentous pathology, predisposes the knee to an increased risk of osteoarthritis. ACL insufficiency results in deterioration of the normal physiologic knee bending culminating in increased anterior tibial translation and increased internal tibial rotation. This leads to increased mean contact stresses in the posterior medial and lateral compartments under anterior and rotational loading. However, surgical reconstruction of the ACL has not been shown to reduce the risk of future OA development back to baseline and has variability based on operative factors of graft choice, timing of surgery, presence of meniscal and chondral abnormalities, and surgical technique. Known strategies to prevent OA development are applicable to patients with ACL deficiency or after ACL reconstruction and include weight management, avoidance of excessive musculoskeletal loading, and strength training. Reconstruction of the ACL does not necessarily prevent osteoarthritis in many of these patients and may depend on several external variables.

No difference in revision rates between single- and double-bundle anterior cruciate ligament reconstruction: a comparative study of 16,791 patients from the Swedish national knee ligament register

PURPOSE

The purpose was to compare revision rates and patient-reported outcomes between single- and double-bundle anterior cruciate ligament (ACL) reconstructions.

METHODS

All patients from the Swedish National Knee Ligament Register from 2005 through 2011 who underwent primary ACL reconstruction with hamstring autografts were included. Patients with concomitant injuries, except meniscal and chondral injuries, were excluded. By December 31, 2011, 16,791 primary isolated ACL reconstructions had been registered, of which 16,281 were single-bundle and 510 were double-bundle. Cumulative revision rates were estimated using Kaplan-Meier analysis. The Knee injury and Osteoarthritis Outcome Score (KOOS) and EQ-5D were calculated at 1- and 2-year follow-ups.

RESULTS

The revision rate showed no statistically significant differences between the groups (P = .30). Over the 7-year observation period, 347 single-bundle (2.1%) and 8 double-bundle (1.6%) ACL reconstructions were revised. No significant differences in the KOOS or EQ-5D were found between the groups postoperatively. In addition, there were no differences in postoperative improvements in the KOOS or EQ-5D at 1- and 2-year follow-ups.

CONCLUSIONS

Revision rates after single- and double-bundle ACL reconstructions were low. No differences were found in revision rates, KOOS, and EQ-5D between the 2 techniques.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Prospective randomized comparison of knee stability and joint degeneration for double- and single-bundle ACL reconstruction

PURPOSE

This study aims to determine the outcome of double-bundle anterior cruciate ligament (ACL) reconstruction using an allograft in comparison with ACL reconstruction using a double-bundle autograft or a single-bundle allograft.

METHODS

A total of 424 patients who accepted primary ACL reconstructions were divided randomly into three groups: double-bundle technique with autograft (DB-AU group, n = 154), double-bundle technique with allograft (DB-AL group, n = 128), and single-bundle technique with allograft (SB group, n = 142). The KT-1000 arthrometer and pivot-shift tests were performed at 3, 12, and 36 months after surgery, and clinical outcome measurements include the Lysholm score and the IKDC rating scales. Radiological assessments evaluated arthritic changes and tunnel expansion at 36 months postoperatively.

RESULTS

The KT-1000 test scores in the DB-AU and DB-AL groups were significantly better than those in the SB group at 12 and 36 months postoperatively (P < 0.05). The pivot-shift tests scores in the DB-AU and DB-AL groups were significantly better than those in the SB group at the 3, 12, and 36 month follow-ups (P < 0.05). Based on the IKDC score and Lysholm score, there were no significant difference between the three groups during follow-up (P > 0.05). At 36 months postoperatively, 42.3 % of patients in the SB group showed a progression in arthritic changes, which was greater than in the DB-AU (29.2 %) and DB-AL (27.3 %) groups (P < 0.05). At 36 months, the rates of tunnel expansion in the DB-AU group and the DB-AL group were lower than in the SB group (P < 0.05).

CONCLUSIONS

Double-bundle ACL reconstruction can be used to achieve better anterior and rotational stability and has a lower rate of arthritic progression and tunnel expansion than the single-bundle procedure.

LEVEL OF EVIDENCE

I.

Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using an Outside-in Technique: Two- to Six-Year Clinical and Radiological Follow-up

PURPOSE

We evaluated the clinical and radiological outcomes of double-bundle anterior cruciate ligament (ACL) reconstruction using an outside-in technique with a follow-up of two- to six-years, especially in terms of the sports activity level and radiological degeneration.

MATERIALS AND METHODS

Sixty-seven patients who were available for a minimum two-year follow-up after double-bundle ACL reconstruction using an outside-in technique were retrospectively evaluated. The mean follow-up period was 43.7 months. The knee function and stability were evaluated before the operation, one year after the operation (short-term follow-up), and more than two years after the operation (last follow-up).

RESULTS

Regarding the knee function, the Lysholm score, International Knee Documentation Committee (IKDC) evaluation, and hop test showed significant improvement. Regarding the stability, the Lachman test, pivot shift test, KT-2000 arthrometer data, and anterior drawer radiographs using Telos showed significant improvement. Regarding the sports activity level, the patients who returned to pre-injury level activity was 68.7% according to the Tegner activity score and 76.1% according to the Cincinnati sports activity scale score. The incidence of aggravated degeneration or development of greater than IKDC grade A degeneration after surgery was 10.4%.

CONCLUSIONS

Double-bundle ACL reconstruction using an outside-in technique showed favorable clinical and radiological outcomes with respect to the knee function and stability, joint degeneraion, and, especially, return to pre-injury sports activity.

Is double-bundle anterior cruciate ligament reconstruction superior to single-bundle? A comprehensive systematic review

PURPOSE

To describe current evidence on single- and double-bundle anterior cruciate ligament (ACL) reconstruction, in terms of differences in knee kinematics, functional outcomes, patient-reported outcomes and graft failures.

METHODS

An electronic search was made using PubMed (MEDLINE), EMBASE and Cochrane Library. Studies published from January 1995 to August 2011 were included, and an updated search was made in PubMed in July 2012. Therapeutic studies, level of evidence I-III, for isolated primary ACL tears written in English comparing single- and double-bundle reconstruction reporting clinical outcome were included. Quality appraisal based on Cochrane Collaboration's tool for assessing risk of bias was performed.

RESULTS

Of 7,154 potentially eligible studies, 60 papers were included (25 randomised controlled trials, 21 prospective comparative studies, 14 retrospective comparative studies), comprising 4,146 patients (2,072 single-bundle, 2,074 double-bundle). Minor differences were found between study types. An analysis of graft failures revealed fewer re-ruptures in double-bundle reconstruction than single-bundle, 19 and 44, respectively. Up to 45 % of the studies reported a superior outcome in double-bundle reconstruction in terms of antero-posterior laxity, measured with the Lachman, anterior drawer, KT-1000/2000 and navigation. Measurements of rotatory laxity revealed superior results in double-bundle reconstruction measured with pivot shift and navigation in 18/42 (8/15 anatomically reconstructed) and 9/20 studies, respectively. Patient-reported outcome measures and functional outcomes did not differ to a large extent; however, differences when identified were almost exclusively in favour of double-bundle reconstruction.

CONCLUSION

Based on current evidence, double-bundle reconstruction appears to have fewer re-ruptures and less antero-posterior and rotatory laxity. Furthermore, no differences were found in short-term patient-reported outcome measures or objective findings. However, detailed statistical analyses of the included studies divided into homogeneous groups are needed to avoid reporting bias and to confirm any statistical difference.

Mid- to long-term results of single-bundle versus double-bundle anterior cruciate ligament reconstruction: randomized controlled trial

PURPOSE

To evaluate the mid-to long-term results of a randomized controlled trial of single-bundle (SB) versus double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using a semitendinosus tendon.

METHODS

Seventy-eight patients who underwent primary ACL reconstruction with an autologous semitendinosus tendon were prospectively randomized into 2 groups: SB reconstruction (n = 39) and DB reconstruction (n = 39). In both groups, grafts were fixed at 30° of flexion with a total tension of 80 N. The following evaluation methods were used: clinical examination, KT-1000 arthrometer (MEDmetric, San Diego, CA) measurement, muscle strength, Tegner activity score, Lysholm score, subjective rating scale regarding patient satisfaction and sports performance level, graft retear, contralateral ACL tear, and additional meniscus surgery.

RESULTS

Fifty-three patients (25 in SB group and 28 in DB group) who were followed up for a minimum of 3 years (mean, 69 months; range, 36 to 140 months) were evaluated. Preoperatively, there were no differences between the groups. Postoperatively, the Lachman and pivot-shift test results were better in the DB group (P = .024 and P < .0001, respectively). KT measurements were better in the DB group (mean, 1.4 mm v 2.7 mm; P = .0023). The Tegner score was also better in the DB group (P = .033). There were no significant differences in range of motion, muscle strength, Lysholm score, subjective rating scale, graft retear, and secondary meniscal tear.

CONCLUSIONS

In ACL reconstruction using the transtibial approach, DB reconstruction was significantly better than SB reconstruction regarding anterior and rotational stability during the 3- to 12-year follow-up. The results of KT measurements and the Lachman and pivot-shift tests were significantly better in the DB group, whereas there was no difference in the anterior drawer test results. The Tegner score was also better in the DB group; however, there were no differences in the other subjective findings.

LEVEL OF EVIDENCE

Level II, lesser-quality prospective randomized trial.

Tunnel communication and increased graft signal intensity on magnetic resonance imaging of double-bundle anterior cruciate ligament reconstruction

PURPOSE

This study aimed to evaluate the association between magnetic resonance imaging (MRI) findings of tunnel communication and increased graft signal intensity (SI) and clinical evaluation of knee stability and outcome after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction.

METHODS

Fifty-nine patients were evaluated with 1.5 T MRI and with clinical evaluation 2 years after DB ACL reconstruction. The MRI finding of tunnel communication was defined as the absence of a bony bridge between the anteromedial (AM) and posterolateral (PL) tunnels. The SI of the intra-articular portion of both grafts was analyzed on proton-density (PD)-weighted and T2-weighted images and graded on a scale, with I being a normal SI similar to that of the posterior cruciate ligament, II being > 50% of the graft having a normal SI, and III being < 50% of the graft having a normal SI. The clinical evaluation of knee stability and function included KT-1,000 arthrometric side-to-side difference, pivot shift test, and International Knee Documentation Committee (IKDC) and Lysholm knee evaluation scores. The association between the MRI findings and the clinical findings was calculated using the Fisher exact test and the 2-tailed t test.

RESULTS

Tunnel communication was seen in the femur in 10% of patients and in the tibia in 27% of patients. Increased graft SI was seen in 15% of the AM grafts and 59% of the PL grafts. No statistically significant association (P < .05) between the MRI findings of tunnel communication or increased graft SI and knee laxity was found.

CONCLUSIONS

The MRI findings of tunnel communication or increased graft SI were not associated with knee laxity 2 years after DB ACL reconstruction. Tibial tunnel communication was associated with increased range of movement with flexion, and increased AM graft SI was associated with reduced range of flexion in the knee.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.

Effect of tunnel placements on clinical and magnetic resonance imaging findings 2 years after anterior cruciate ligament reconstruction using the double-bundle technique

PURPOSE

The purpose of the study reported here was to find out if the clinical and magnetic resonance imaging (MRI) findings of a reconstructed anterior cruciate ligament (ACL) have an association. Our hypothesis, which was based on the different functions of the ACL bundles, was that the visibility of the anteromedial graft would have an impact on anteroposterior stability, and the visibility of the posterolateral graft on rotational stability of the knee.

METHODS

This study is a level II, prospective clinical and MRI study (NCT02000258). The study involved 75 patients. One experienced orthopedic surgeon performed all double-bundle ACL reconstructions. Two independent examiners made the clinical examinations at 2-year follow-up: clinical examination of the knee; KT-1000, International Knee Documentation Committee and Lysholm knee evaluation scores; and International Knee Documentation Committee functional score. The MRI evaluations were made by two musculoskeletal radiologists separately, and the means of these measurements were used.

RESULTS

We found that the location of the graft in the tibia had an impact on the MRI visibility of the graft at 2-year follow-up. There were significantly more partially or totally invisible grafts if the insertion of the graft was more anterior in the tibia. No association was found between the clinical results and the graft locations.

CONCLUSION

Anterior graft location in the tibia can cause graft invisibility in the MRI 2 years after ACL reconstruction, but this has no effect on the clinical recovery of the patient.

[Injuries of the anterior cruciate ligament in athletes]

Anterior cruciate ligament ruptures represent serious injuries for athletes which are often associated with accompanying injuries and lead to relevant kinematic alterations in the femorotibial roll-glide mechanism of the knee joint. Instability resulting in recurrent giving way events, as well as instability-related meniscal and cartilage lesions can cause functional long-term impairment that may limit the athlete's career. Anterior cruciate ligament replacement is therefore considered to be the gold standard for recovery of physical performance and to prevent secondary meniscal and cartilage damage. Continuous changes in the reconstruction of the anterior cruciate ligament have led to a variety of different methods, including graft choice, fixation devices and surgical techniques, which support the consideration of individual requirements of the athlete as well as sport-specific aspects. One of the main factors for restoring stability and the physiological kinematic roll-glide mechanism of the knee is an anatomical tunnel placement as well as a stable graft fixation in the tibia and femur. By achieving of these fundamental technical requirements an early functional rehabilitation and accelerated recovery of neuromuscular skills, strength and coordination can be achieved, so that an early return to sport activities is possible.

Comparison of double-bundle anterior cruciate ligament (ACL) reconstruction and single-bundle reconstruction with remnant pull-out suture

PURPOSE

The purpose of this study was to evaluate the stability and functional outcomes of anterior cruciate ligament (ACL) reconstruction by tensioning of the ACL remnant using pull-out sutures compared with ACL double-bundle reconstruction.

METHODS

Forty-four patients were included in single-bundle reconstruction with remnant tensioning group (Group 1), and 56 patients were included in the double-bundle reconstruction group (Group 2). The remnant tissue was tensioned to the direction of posterolateral bundle, which unrelated to the type of remnant bundle. Objective knee stability was evaluated by anterior stress radiography, KT-1000 and lateral pivot shift tests. The Tegner activity scale, International Knee Documentation Committee and OrthopädischeArbeitsgruppeKnie scoring systems were used for clinical evaluation.

RESULTS

No statistically significant intergroup differences were observed in mechanical stability and clinical results (n.s). However, surgical time of remnant tensioning group is shorter than double-bundle reconstruction group (P = 0.005).

CONCLUSION

Remnant tensioning suture with single-bundle reconstruction could be used with positive results as good as double-bundle technique if a good ACL remnant was found bridging the femur and tibia, rather than debride or damage to the remnant tissue during operation.

LEVEL OF EVIDENCE

Retrospective, comparative cohort study, Level IV.

Clinical outcomes of remnant preserving augmentation in anterior cruciate ligament reconstruction: a systematic review

PURPOSE

The objective of this study was to systematically review the current evidence to see whether the remnant preservation techniques could obtain better clinical outcomes than the standard anterior cruciate ligament reconstruction procedure.

METHODS

The authors systematically searched online databases to identify the studies which compared the remnant preservation techniques with the standard techniques. Two reviewers independently extracted data and evaluated the methodological quality of each study. Clinical outcomes in terms of knee stability, clinical scores, vascularization, proprioception, tibial tunnel enlargement and complications were qualitatively compared.

RESULTS

Thirteen studies met the inclusion criteria for review. Compared with the standard procedure, significantly better results regarding knee stability in the remnant preserving group were reported in two of nine studies in the instrumented knee laxity, one of eight studies in the Lachman test and none of eight studies regarding the pivot shift test. Five studies assessed International Knee Documentation Committee scores but found no differences. One of two studies indicated significantly earlier revascularization according to the signal/noise quotient value of the graft on magnetic resonance imaging. One of two studies indicated significantly better proprioceptive function in terms of joint position sense using the reproduction of passive positioning test. Two of two studies showed significantly less tibial tunnel enlargement in the remnant preserving group. None of the studies showed significant increase in the risk of cyclops lesion formation and the loss of knee range of motion in the remnant augmentation group.

CONCLUSIONS

The current evidence suggests that the short-term clinical outcomes of patients with the remnant augmentation technique are comparable, if not superior, with that of patients undergoing the standard technique, although it is insufficient to justify the remnant preserving augmentation as a routine treatment for anterior cruciate ligament ruptures.

LEVEL OF EVIDENCE

Systematic review, Level IV.

Factors influencing graft impingement on the wall of the intercondylar notch after anatomic double-bundle anterior cruciate ligament reconstruction

BACKGROUND

Anatomic placement of the bone tunnel reportedly reduces impingement of the graft with the intercondylar roof, but as a trade-off, the risk of impingement with the lateral wall of the intercondylar notch would increase instead in anatomic double-bundle anterior cruciate ligament (ACL) reconstruction.

PURPOSE

The 2 grafts for the anteromedial bundle (AMB) and posterolateral bundle (PLB) were separately analyzed for the frequency of and risk factors for graft impingement on the wall of the intercondylar notch.

STUDY DESIGN

Case control study; Level of evidence, 3.

METHODS

A total of 51 patients (53 knees) who underwent primary anatomic double-bundle ACL reconstruction were enrolled. Based on the graft orientation plane reconstructed with 3-dimensional imaging software, graft-wall impingement was defined as overlap between the lateral wall of the notch and the line connecting each center of the intra-articular apertures of the femoral and tibial bone tunnels. The rate of wall impingement was assessed for each bundle. Parameters for bone tunnel positioning in the femur and tibia, notch width index, and knee joint rotation angle were compared between patients with and without wall impingement. The most important risk factors for wall impingement were assessed by logistic regression analysis.

RESULTS

Wall impingement for the AMB was observed in 22 knees (42%), whereas no patients exhibited wall impingement for the PLB. Regarding femoral bone tunnel positioning according to the quadrant method, the AMB bone tunnel was placed significantly higher in impingement-positive patients than in impingement-negative patients (P = .03). Regarding tibial tunnel positioning, the tunnel was placed significantly more anteriorly (P = .02) and laterally (P = .02) in the impingement-positive group than in the impingement-negative group. Bone tunnels positioned 48% to 50% from the medial border of the tibia demonstrated a 100% incidence of wall impingement. Based on logistic regression analysis, lateral deviation of the AMB tibial bone tunnel was significantly associated with wall impingement (odds ratio, 1.403; P = .048).

CONCLUSION

The tibial bone tunnel position in the coronal orientation was most likely associated with wall impingement. Considering that tibial bone tunnels are generally created with the knee in 90° of flexion and move laterally as the knee extends because of screw-home movement, the AMB bone tunnel for the tibia should be positioned as medially as possible within its footprint to minimize the risk of wall impingement after anatomic double-bundle ACL reconstruction.

Surgical Predictors of Early Revision Surgery After Anterior Cruciate Ligament Reconstruction: Results From the Swedish National Knee Ligament Register on 13,102 Patients

BACKGROUND

An important objective of anterior cruciate ligament (ACL) registries is to detect and report early graft failure and revision surgery after ACL reconstruction.

PURPOSE

To investigate surgical variables and identify predictors of revision surgery after ACL reconstruction.

STUDY DESIGN

Prospective cohort study; Level of evidence, 2.

METHODS

This prospective cohort study was based on data from the Swedish National Knee Ligament Register during the years 2005 through 2011. Eight surgical variables were investigated: graft selection, graft width, single-bundle or double-bundle techniques, femoral graft fixation, tibial graft fixation, injury-to-surgery interval, injuries to menisci, and injuries to cartilage. The primary endpoint was the 2-year incidence of revision surgery. Relative risks (RRs) and 95% confidence intervals (CIs) were calculated and adjusted for confounders by use of multivariate statistics.

RESULTS

A total of 13,102 patients were included (5541 women [42%] and 7561 men [58%]; P < .001). Hamstring tendon autografts accounted for 90% (11,764 patients) of all reconstructions, of which 96% were performed with a single-bundle technique (11,339 patients). Patellar tendon autografts accounted for the remaining 10% (1338 patients). At index reconstruction, observed injuries to menisci and cartilage were common (40% and 28%, respectively). The overall 2-year incidence of revision surgery was 1.60% (women, 1.57%; men, 1.63%; P = .854). Patients with metal interference screw fixation of a semitendinosus tendon autograft on the tibia had a significantly reduced risk of early revision surgery (RR = 0.32; 95% CI, 0.12-0.90; P = .031).

CONCLUSION

Metal interference screw fixation of a semitendinosus tendon autograft on the tibia was an independent predictor of significantly lower 2-year incidence of revision surgery. Graft selection, graft width, a single-bundle or a double-bundle technique, femoral graft fixation, the injury-to-surgery interval, and meniscus injury were not predictors of early revision surgery.

Anterior cruciate ligament reconstruction practice patterns by NFL and NCAA football team physicians

PURPOSE

This study aimed to determine practice patterns for National Football League (NFL) and National Collegiate Athletic Association (NCAA) Division I football team orthopaedic surgeons regarding management of anterior cruciate ligament (ACL) tears in elite, young, and middle-aged recreational athletes.

METHODS

Two hundred sixty-seven NFL and NCAA Division I team orthopaedic surgeons were surveyed through an online survey. A 9-question survey assessed surgeon experience, graft choice, femoral tunnel drilling access, number of graft bundles, and rehabilitation after ACL reconstruction.

RESULTS

One hundred thirty-seven team orthopaedic surgeons (51%) responded (mean experience 16.75 ± 8.7 years). Surgeons performed 82 ± 50 ACL reconstructions in 2012. One hundred eighteen surgeons (86%) would use bone-patellar tendon-bone (BPTB) autografts to treat their starting running backs. Ninety (67%) surgeons drill the femoral tunnel through an accessory anteromedial portal (26% through a transtibial portal). Only 1 surgeon prefers a double-bundle to a single-bundle reconstruction. Seventy-seven (55.8%) surgeons recommend waiting at least 6 months before return to sport, whereas 17 (12.3%) wait at least 9 months. No surgeon recommends waiting 12 months or more before return to sport. Eighty-eight (64%) surgeons do not recommend a brace for their starting running backs during sport once they return to play.

CONCLUSIONS

BPTB is the most frequently used graft for ACL reconstruction by NFL and NCAA Division I team physicians in their elite-level running backs. Nearly all surgeons always use a single-bundle technique, and most do not recommend a brace on return to sport in running backs. Return to sport most commonly occurs at least 6 months postoperatively, with some surgeons requiring a normal examination and normal return-to-sport testing (single leg hop).

Anatomic single- versus double-bundle ACL reconstruction: a meta-analysis

PURPOSE

To determine whether anatomic double-bundle anterior cruciate ligament (ACL) reconstruction compared to anatomic single-bundle ACL reconstruction more effectively restored antero-posterior (A-P) laxity, rotatory laxity and reduced frequency of graft rupture. Our hypothesis was that anatomic double-bundle ACL reconstruction results in superior rotational knee laxity and fewer graft ruptures due to its double-bundle tension pattern, compared with anatomic single-bundle ACL reconstruction.

METHODS

An electronic search was performed using the PubMed, EMBASE and Cochrane Library databases. All therapeutic trials written in English reporting knee kinematic outcomes and graft rupture rates of primary anatomic double- versus single-bundle ACL reconstruction were included. Only clinical studies of levels I-II evidence were included. Data regarding kinematic tests were extracted and included pivot-shift test, Lachman test, anterior drawer test, KT-1000 measurements, A-P laxity measures using navigation and total internal-external (IRER) laxity measured using navigation, as well as graft failure frequency.

RESULTS

A total of 7,154 studies were identified of which 15 papers (8 randomized controlled trials and 7 prospective cohort studies, n = 970 patients) met the eligibility criteria. Anatomic ACL double-bundle reconstruction demonstrated less anterior laxity using KT-1000 arthrometer with a standard mean difference (SMD) = 0.36 (95% CI 0.214-0.513, p < 0.001) and less A-P laxity measured with navigation (SMD = 0.29 95% CI 0.01-0.565, p = 0.042). Anatomic double-bundle ACL reconstruction did not lead to significant improvements in pivot-shift test, Lachman test, anterior drawer test, total IRER or graft failure rates compared to anatomic single-bundle ACL reconstruction.

CONCLUSION

Anatomic double-bundle ACL reconstruction is superior to anatomic single-bundle reconstruction in terms of restoration of knee kinematics, primarily A-P laxity. Whether these improvements of laxity result in long-term improvement of clinical meaningful outcomes remains uncertain.

LEVEL OF EVIDENCE

II.

A prospective study to assess the outcomes of revision anterior cruciate ligament reconstruction

PURPOSE

Continuously increasing numbers of primary anterior cruciate ligament (ACL) reconstructions invites a parallel increase in graft failures and need for revision ACL reconstruction surgery. High failure rates has previously stigmatised the revision surgery. We performed this study using multiple outcome measures together with clinical examination to offer a full assessment of the outcomes of this procedure.

METHODS

Twenty patients, with mean age of 29.4 years (17-50 years), were included in this study prior to their revision ACL reconstruction surgery. All patients were followed prospectively collecting the Knee injury and Osteoarthritis Outcome (KOOS), International Knee Documentation Committee (IKDC) and Tegner-Lysholm scores pre- and post-operatively together with clinical assessment of the antero-posterior knee laxity.

RESULTS

After a mean follow up interval of 30 months (16-60 months) significant post-operative improvement of IKDC, Tegner-Lysholm scores and knee antero-posterior laxity together with the Symptoms, Activities of Daily Living (ADL) and Quality of Life (QOL) components of the KOOS score was noticed (P < 0.05). However, there was no similar improvement in pain and sports components of the KOOS score (P > 0.05). There was no difference in the outcomes of different graft types.

CONCLUSION

Good outcomes of revision ACL reconstruction surgery are achievable. The use of different graft types did not affect the outcome of the procedure. Most of the patients opted to less aggressive sports participation after the revision procedure.

Basic science of anterior cruciate ligament injury and repair

Injury to the anterior cruciate ligament (ACL) is one of the most devastating and frequent injuries of the knee. Surgical reconstruction is the current standard of care for treatment of ACL injuries in active patients. The widespread adoption of ACL reconstruction over primary repair was based on early perception of the limited healing capacity of the ACL. Although the majority of ACL reconstruction surgeries successfully restore gross joint stability, post-traumatic osteoarthritis is commonplace following these injuries, even with ACL reconstruction. The development of new techniques to limit the long-term clinical sequelae associated with ACL reconstruction has been the main focus of research over the past decades. The improved knowledge of healing, along with recent advances in tissue engineering and regenerative medicine, has resulted in the discovery of novel biologically augmented ACL-repair techniques that have satisfactory outcomes in preclinical studies. This instructional review provides a summary of the latest advances made in ACL repair. Cite this article: Bone Joint Res 2014;3:20-31.

Functional Performance Testing After Anterior Cruciate Ligament Reconstruction: A Systematic Review

Background:

When to allow an athlete to return to unrestricted sporting activity after anterior cruciate ligament (ACL) reconstruction remains controversial.

Purpose:

To report the results of functional performance testing reported in the literature for individuals at differing time points following ACL reconstruction and to examine differences between graft types.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review of Medline, Scopus, and Cochrane Central Register of Controlled Trials was performed using PRISMA guidelines. Inclusion criteria were English-language studies that examined any functional rehabilitation test from 6 months to 2 years following ACL reconstruction. All patient-, limb-, and knee-specific demographics were extracted from included investigations. All functional rehabilitation tests were analyzed and compared when applicable.

Results:

The search term returned a total of 890 potential studies, with 88 meeting inclusion and exclusion criteria. A total of 4927 patients were included, of which 66% were male. The mean patient age was 26.5 ± 3.4 years. The predominant graft choices for reconstruction were bone–patellar tendon–bone (BPTB) autograft (59.8%) and hamstring autograft (37.9%). The most commonly reported functional tests were the hop tests. The results of these functional tests, as reported in the Limb Symmetry Index (LSI), improved with increasing time, with nearly all results greater than 90% at 1 year following primary ACL reconstruction. At 6 months postoperatively, a number of isokinetic strength measurements failed to reach 80% LSI, most commonly isokinetic knee extension testing in both BPTB and hamstring autograft groups. The knee flexion strength deficit was significantly less in the BPTB autograft group as compared with those having hamstring autograft at 1 year postoperatively, while no significant differences were found in isokinetic extension strength between the 2 groups.

Conclusion:

Hop testing was the most commonly reported functional test following ACL reconstruction. Increases in performance on functional tests were predictably seen as time increased following surgery. Those with hamstring autografts may experience increased strength deficits with knee flexion versus those having BPTB autograft. These data provide information that may assist providers in determining timing of return to unrestricted sporting activity.

Current trends in anterior cruciate ligament reconstruction

The advances in the knowledge of anatomy, surgical techniques, and fixation devices have led to the improvement of anterior cruciate ligament (ACL) reconstruction over the past 10 years. Nowadays, double bundle and anatomical single bundle ACL reconstruction that more closely restores the normal anatomy of the ACL are becoming popular. Although there is still no definite conclusion whether double bundle ACL reconstruction provides better clinical results than single bundle reconstruction, the trend has shifted to anatomic reconstruction regardless of single bundle or double bundle techniques. We could not find any significant differences in the clinical outcomes and stability after ACL reconstruction according to the type of graft or fixation device. Therefore, surgeons should select an ideal ACL reconstruction according to the patient's condition and surgeon's experience.