Causes for failure of ACL reconstruction and influence of meniscectomies after revision

Meniscal and Articular Cartilage Predictors of Clinical Outcome After Revision Anterior Cruciate Ligament Reconstruction

BACKGROUND

Revision anterior cruciate ligament (ACL) reconstruction has been documented to have worse outcomes compared with primary ACL reconstructions.

PURPOSE/HYPOTHESIS

The purpose of this study was to determine if the prevalence, location, and/or degree of meniscal and chondral damage noted at the time of revision ACL reconstruction predicts activity level, sports function, and osteoarthritis symptoms at 2-year follow-up. The hypothesis was that meniscal loss and high-grade chondral damage noted at the time of revision ACL reconstruction will result in lower activity levels, decreased sports participation, more pain, more stiffness, and more functional limitation at 2 years after revision surgery.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Between 2006 and 2011, a total of 1205 patients who underwent revision ACL reconstruction by 83 surgeons at 52 hospitals were accumulated for study of the relationship of meniscal and articular cartilage damage to outcome. Baseline demographic and intraoperative data, including the International Knee Documentation Committee (IKDC) subjective knee evaluation, Knee injury and Osteoarthritis Outcome Score (KOOS), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Marx activity score, were collected initially and at 2-year follow-up to test the hypothesis. Regression analysis was used to control for age, sex, body mass index, smoking status, activity level, baseline outcome scores, revision number, time since last ACL reconstruction, incidence of having a previous ACL reconstruction on the contralateral knee, previous and current meniscal and articular cartilage injury, graft choice, and surgeon years of experience to assess the meniscal and articular cartilage risk factors for clinical outcomes 2 years after revision ACL reconstruction.

RESULTS

At 2-year follow-up, 82% (989/1205) of the patients returned their questionnaires. It was found that previous meniscal injury and current articular cartilage damage were associated with the poorest outcomes, with prior lateral meniscectomy and current grade 3 to 4 trochlear articular cartilage changes having the worst outcome scores. Activity levels at 2 years were not affected by meniscal or articular cartilage pathologic changes.

CONCLUSION

Prior lateral meniscectomy and current grade 3 to 4 changes of the trochlea were associated with worse outcomes in terms of decreased sports participation, more pain, more stiffness, and more functional limitation at 2 years after revision surgery, but they had no effect on activity levels.

REGISTRATION

NCT00625885.

Posterior Wall Blowout in Anterior Cruciate Ligament Reconstruction: A Review of Anatomic and Surgical Considerations

Violation of the posterior femoral cortex, commonly referred to as posterior wall blowout, can be a devastating intraoperative complication in anterior cruciate ligament (ACL) reconstruction and lead to loss of graft fixation or early graft failure. If cortical blowout occurs despite careful planning and adherence to proper surgical technique, a thorough knowledge of the anatomy and alternative fixation techniques is imperative to ensure optimal patient outcomes. This article highlights anatomic considerations for femoral tunnel placement in ACL reconstruction and techniques for avoidance and salvage of a posterior wall blowout.

Posterior Wall Blowout During Anterior Cruciate Ligament Reconstruction: Suspensory Cortical Fixation With a Screw and Washer Post

Posterior wall blowout can be a devastating intraoperative complication in anterior cruciate ligament reconstruction. This loss of osseous containment can cause difficulty with graft fixation and can potentially lead to early graft failure if unrecognized and left untreated. If cortical blowout occurs despite careful planning and proper surgical technique, a thorough knowledge of the local anatomy and surgical salvage options is paramount to ensure positive patient outcomes. This article highlights our preferred salvage technique using suspensory cortical fixation with a screw and washer construct.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction

The number of primary anterior cruciate ligament (ACL) tears is rapidly increasing. In patients who wish to return to their preoperative level of function, specifically as it pertains to participation in sports, the gold standard of treatment following an ACL tear remains an anterior cruciate ligament (ACL) reconstruction. Despite a majority of good/excellent results following primary ACL reconstruction, there is a growing subset of patients with persistent or recurrent functional instability who require revision ACL reconstruction. Preoperative planning for revision ACL reconstruction requires a careful understanding of the root cause of ACL failure, including possible technical causes of primary ACL failure and the presence of combined knee pathology that was not addressed at the index ACL reconstruction. The decision to perform 2-stage revision ACL reconstruction is multifactorial and is reached by technical considerations that may make a 1-stage revision less optimal, including tunnel widening, arthrofibrosis, active infection, and others. Concomitant knee pathology such as meniscal deficiency, malalignment (including an increase in posterior tibial slope), chondral lesions, and other ligamentous laxity may also require a staged approach to treatment. This evidence-based review covers the indications for 2-stage revision ACL reconstruction, surgical techniques, evidence for and technique of bone grafting prior ACL tunnels, and outcomes of 2-stage revision stratified by initial cause of ACL reconstruction failure. With proper preoperative planning and an understanding of the cause of failure following the primary ACL reconstruction, revision ACL reconstruction can offer excellent outcomes in the motivated patient. [Orthopedics. 2016; 39(3):e456-e464.].

Posteromedial Meniscocapsular Lesions Increase Tibiofemoral Joint Laxity With Anterior Cruciate Ligament Deficiency, and Their Repair Reduces Laxity

BACKGROUND

Injury to the posteromedial meniscocapsular junction has been identified after anterior cruciate ligament (ACL) rupture; however, there is a lack of objective evidence investigating how this affects knee kinematics or whether increased laxity can be restored by repair. Such injury is often overlooked at surgery, with possible compromise to results.

HYPOTHESES

(1) Sectioning the posteromedial meniscocapsular junction in an ACL-deficient knee will result in increased anterior tibial translation and rotation. (2) Isolated ACL reconstruction in the presence of a posteromedial meniscocapsular junction lesion will not restore intact knee laxity. (3) Repair of the posteromedial capsule at the time of ACL reconstruction will reduce tibial translation and rotation to normal. (4) These changes will be clinically detectable.

STUDY DESIGN

Controlled laboratory study.

METHODS

Nine cadaveric knees were mounted in a test rig where knee kinematics were recorded from 0° to 100° of flexion by use of an optical tracking system. Measurements were recorded with the following loads: 90-N anterior-posterior tibial forces, 5-N·m internal-external tibial rotation torques, and combined 90-N anterior force and 5-N·m external rotation torque. Manual Rolimeter readings of anterior translation were taken at 30° and 90°. The knees were tested in the following conditions: intact, ACL deficient, ACL deficient and posteromedial meniscocapsular junction sectioned, ACL deficient and posteromedial meniscocapsular junction repaired, ACL patellar tendon reconstruction with posteromedial meniscocapsular junction repair, and ACL reconstructed and capsular lesion re-created. Statistical analysis used repeated-measures analysis of variance and post hoc paired t tests with Bonferroni correction.

RESULTS

Tibial anterior translation and external rotation were both significantly increased compared with the ACL-deficient knee after posterior meniscocapsular sectioning (P < .05). These parameters were restored after ACL reconstruction and meniscocapsular lesion repair (P > .05).

CONCLUSION

Anterior and external rotational laxities were significantly increased after sectioning of the posteromedial meniscocapsular junction in an ACL-deficient knee. These were not restored after ACL reconstruction alone but were restored with ACL reconstruction combined with posterior meniscocapsular repair. Tibial anterior translation changes were clinically detectable by use of the Rolimeter.

CLINICAL RELEVANCE

This study suggests that unrepaired posteromedial meniscocapsular lesions will allow abnormal meniscal and tibiofemoral laxity to persist postoperatively, predisposing the knee to meniscal and articular damage.

Regeneration of knee joint menisci – methods review

At present, there is no need to convince anyone that menisci are crucial structures dealing with a huge number of responsibilities, and its absence in a knee joint results in irretrievable chondral damage. A lot of methods have been recently developed to treat meniscal tears: physical therapy as a first and, for some cases, a last step, bonding by biodegradable sutures, screws, or arrows, collagen and polyurethane scaffolds designed for partial meniscus replacement, and finally allograft transplantation. However, all of them have numerous limitations and can be used in specific conditions only. That is the reason why partial and total meniscectomy is up to this time a common operation in the case of degenerative or complex meniscus tears despite its well-known degenerative consequences. Trials to overcome those limitations are ongoing, and the challenge to invent a long-term successful regeneration method or to design a substitute that well mimics an anatomical meniscus is still in front of us.

Case series: Revision anterior cruciate ligament reconstructions using patellar tendon autografts

BACKGROUND

Using intra-operative findings and clinical results, including return to play (RTP) at the pre-injury level, this study investigated the causes of primary graft failure after revision anterior cruciate ligament (ACL) reconstruction with bone-patellar-tendon-bone (BPTB) autografts.

METHODS

A total of 54 patients were followed for a mean of 38.2 ± 10.2 months post-surgery. Subjective and objective results were evaluated using single assessment numeric evaluation (SANE) scores, Lachman tests, KT-2000 arthrometer results, and pivot-shift tests. The change in each patient's Tegner activity scale and RTP at the pre-injury level were also evaluated.

RESULTS

Inappropriate positioning of the tunnels was the most important reason (54%) for primary graft failure. After revision surgery, anterior knee stability was significantly improved (1.2 (mean) ± 1.2 (SD)mm vs 4.5(mean) ± 1.9 (SD)mm; P < 0.01). Two (4%) patients sustained revision graft ruptures while two (4%) sustained contralateral knee ACL tears. The rate of RTP at the pre-injury level was 67% (36 patients), and mean SANE scores at the time of RTP were higher than before surgery (74.8 ± 13.8 points vs 24.1 ± 16.4; P<0.001). The average time from primary graft failure to revision surgery was shorter (12.2 (mean) ± 4.0 (SD) vs 37.6 (mean) ± 8.8 (SD)months; P < 0.01) and the ratio of major cartilage injury was lower (39% vs 83%; P < 0.05) in the RTP group than that in the non-RTP group.

CONCLUSIONS

The time from primary graft failure to revision surgery and the extent of the cartilage injury are major factors in RTP after revision ACL reconstructions.

Meniscal integrity predicts laxity of anterior cruciate ligament reconstruction

PURPOSE

The aim of this study was to evaluate the incidence of failure of anterior cruciate ligament (ACL) reconstruction and to assess the prognostic factors for such an outcome.

METHODS

A prospective inception cohort of patients undergoing ACL reconstruction was analysed for failure (patient reported symptoms of rotational instability, a clinically positive pivot shift, MRI or arthroscopy showing ACL graft rupture). Risk factors evaluated included medial and lateral meniscal deficiency, medial and lateral meniscal repair, age, gender, BMI, graft size and time to surgery. Survival analysis was performed using the Kaplan-Meier method. Prognostic factors were assessed using the Cox proportional hazard model to investigate whether covariate risk factors influenced graft survival.

RESULTS

One hundred and twenty-three patients were available for final analysis at a follow-up of 2 years. Eighteen patients satisfied the criteria of failure (15.4 %). Risk factors for failure were medial meniscal deficiency (hazard ratio 4.5; 95 % CI 1.8-11.5; p = 0.002), or lateral meniscal deficiency (hazard ratio 3.5; 95 % CI 1.3-9.3; p = 0.01). At 2-year follow-up, ACL survival was 94.5 % (95 % CI 89-100) for patients with intact menisci and 69 % (95 % CI 56-86) for those with deficiency of the medial or lateral meniscus (log-rank test p = 0.017). Patients were 4.9 times more likely to fail if they had a deficient medial or lateral meniscus. Those patients who underwent meniscal repair did not demonstrate any increased risk of failure.

CONCLUSION

Medial and lateral meniscal tears are important prognostic factors that influence the survival of ACL reconstruction. Surgeons should endeavour to repair all meniscal tears associated with ACL reconstruction.

LEVEL OF EVIDENCE

II.

The Meniscus-Deficient Knee: Biomechanics, Evaluation, and Treatment Options

Meniscal tears are the most common knee injury, and partial meniscectomies are the most common orthopaedic surgical procedure. The injured meniscus has an impaired ability to distribute load and resist tibial translation. Partial or complete loss of the meniscus promotes early development of chondromalacia and osteoarthritis. The primary goal of treatment for meniscus-deficient knees is to provide symptomatic relief, ideally to delay advanced joint space narrowing, and ultimately, joint replacement. Surgical treatments, including meniscal allograft transplantation (MAT), high tibial osteotomy (HTO), and distal femoral osteotomy (DFO), are options that attempt to decrease the loads on the articular cartilage of the meniscus-deficient compartment by replacing meniscal tissue or altering joint alignment. Clinical and biomechanical studies have reported promising outcomes for MAT, HTO, and DFO in the postmeniscectomized knee. These procedures can be performed alone or in conjunction with ligament reconstruction or chondral procedures (reparative, restorative, or reconstructive) to optimize stability and longevity of the knee. Complications can include fracture, nonunion, patella baja, compartment syndrome, infection, and deep venous thrombosis. MAT, HTO, and DFO are effective options for young patients suffering from pain and functional limitations secondary to meniscal deficiency.

Tibial slope correction combined with second revision ACL produces good knee stability and prevents graft rupture

PURPOSE

Revision ACL reconstruction requires careful analysis of failure causes particularly in cases of two previous graft ruptures. Intrinsic factors as excessive tibial slope or narrow femoral notch increase failure risks but are rarely addressed in revision surgery. The authors report outcomes, at minimum follow-up of 2 years, for second revision ACL reconstructions combined with tibial deflexion osteotomy for correction of excessive slope (>12°).

METHODS

Nine patients that underwent second revision ACL reconstruction combined with tibial deflexion osteotomy were retrospectively studied. The mean age was 30.3 ± 4.4 years (median 28; range 26-37), and mean follow-up was 4.0 ± 2.0 years (median 3.6; range 2.0-7.6). Autografts were harvested from the quadriceps tendon (n = 8) or hamstrings (n = 1), and tibial osteotomy was done by anterior closing wedge, without detachment of the patellar tendon, to obtain a slope of 3° to 5°.

RESULTS

All patients had fused osteotomies, stable knees, and there were no intraoperative or postoperative complications. The mean posterior tibial slope decreased from 13.2° ± 2.6° (median 13°; range 12°-18°) preoperatively to 4.4° ± 2.3° (median 4°; range 2°-8°) postoperatively. The mean Lysholm score was 73.8 ± 5.8 (median 74; range 65-82), and the IKDC-SKF was 71.6 ± 6.1 (median 72.8; range 62.2-78.5).

CONCLUSION

The satisfactory results of second revision ACL reconstruction combined with tibial deflexion osteotomy at minimum follow-up of 2 years suggest that tibia slope correction protects reconstructed ACL from fatigue failure in this study. The authors stress the importance of careful analysis failure causes prior to revision ACL reconstruction, and recommend correction of tibial slope if it exceeds 12°, to reduce the risks of graft retear.

LEVEL OF EVIDENCE

III.

The role of high tibial osteotomy in the treatment of knee laxity: a comprehensive review

PURPOSE

The purpose of this study is to review the indications for and outcomes of high tibial osteotomy in the treatment of patients with chronic knee laxity.

METHODS

A comprehensive literature review was performed to identify surgical indications and results of high tibial osteotomy for the treatment of chronic knee laxity.

RESULTS

Four distinct situations were identified in which a high tibial osteotomy may be advantageous: (1) anterior laxity with varus osteoarthritis, (2) chronic anterior laxity in the setting of varus with lateral ligamentous laxity, (3) chronic anterior laxity in the setting of a high tibial slope, and (4) chronic posterior laxity or posterolateral corner injury. A total of 24 studies were included in this report, including reports of the treatment of 410 knees as well as several review articles. The most frequently reported indication for that addition of HTO was anterior laxity in the setting of varus OA, which was noted to have good results, minimizing anterior knee laxity and allowing return to sports, while reducing the progression of osteoarthritis. More advanced cases in which lateral structures have also become stretched and incompetent are an excellent indication for HTO, with the need for subsequent lateral procedures dependent on the degree of varus laxity and especially hyperextension that is present. Excessive tibial slope has been identified as a cause of ACL reconstruction failure, and some authors have recommended addressing very high slope in revision cases. In knees with chronic posterior or posterolateral instability, correction of alignment first is generally recommended, with subsequent ligamentous procedures performed when instability persists.

CONCLUSIONS

Knees with chronic instability pose a difficult treatment challenge. In all cases, the contribution of coronal plane alignment to varus-valgus knee stability must be carefully considered and addressed prior to ligament surgery. Sagittal plane alignment is also key and must not be overlooked. Such considerations drive the indication for osteotomy as well as the type of osteotomy that is chosen. Level of evidence IV.

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

INTRODUCTION

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

HYPOTHESIS

Control is improved with computer assisted navigation.

MATERIAL AND METHODS

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

RESULTS

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

CONCLUSION

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

Biomechanical evaluation of knee kinematics after anatomic single- and anatomic double-bundle ACL reconstructions with medial meniscal repair

PURPOSE

To evaluate knee laxity after anatomic ACL reconstruction with additional suture repair of a medial meniscus tear.

METHODS

Kinematics of the intact knee were determined in 12 human cadaver specimens in response to a 134-N anterior tibial load (aTT) and a combined rotatory load of 10 Nm valgus and 4 Nm internal tibial rotation (aTTPS) using a robotic/universal force moment sensor testing system. Subsequently, the ACL was resected following the creation of a standardized tear of the medial meniscus, a standard meniscus repair and an ACL reconstruction using an anatomic single-bundle (6) or an anatomic double-bundle technique (6). Knee kinematics were determined following every sub-step.

RESULTS

Significant increase of aTT in the ACL-deficient knee was found (p ≤ 0.001) with a further increase in the ACL-deficient knee with additional medial meniscal rupture (p ≤ 0.001). ACL reconstructions significantly decreased aTT compared with the ACL and meniscus-ruptured knee. No significant differences were seen between the intact knee and the ACL-reconstructed knee with additional meniscal repair (p < 0.05). In response to a simulated pivot shift, aTTPS in the intact knee significantly increased in the ACL-deficient knee and meniscus-ruptured knee (p = 0.005). No significant differences in knee kinematics were found between SB as well as DB ACL reconstruction with additional medial meniscal repair compared with the intact knee. Comparison of SB versus DB ACL reconstruction did not reveal any significant differences in a simulated Lachman test or simulated pivot shift test (n.s.).

CONCLUSIONS

aTT as well as aTTPS significantly increased with ACL deficiency compared with the intact knee; additional medial meniscal rupture further increased aTT. Anatomic ACL reconstruction with medial meniscal repair did not reveal significant differences in knee kinematics compared with the intact knee. Comparison of anatomic SB versus DB ACL reconstruction with additional repair of the medial meniscus did not show significant differences neither in a simulated Lachman nor in a simulated pivot shift test.

Variability of tunnel positioning in fluoroscopic-assisted ACL reconstruction

PURPOSE

Intraoperative fluoroscopy has been proposed as a feasible method to improve the accuracy of anatomical tunnel positioning. However, it has so far not been determined, whether this technique reduces the variability of tunnel positioning in a clinical set-up. Therefore, the purpose of this study was to determine the variability of tunnel positions applying intraoperative fluoroscopy.

METHODS

Femoral and tibial tunnel positions of 112 fluoroscopic ACL reconstruction cases were determined according to validated radiological measurement methods. Mean positions, standard deviations and ranges were calculated to determine the variability of the tunnel positions. Subgroup variability analysis was performed to analyse cases in which tunnel positions were corrected.

RESULTS

Applying intraoperative fluoroscopy, the variability of tunnel positions was found to be 3 % at the femur (range 15.4 %) and 2.3 % at the tibia (9.7 %). In 34 cases (30.0 %), non-satisfactory tunnel positions were identified and could be corrected achieving more accurate positions regarding to radiological parameters (14× femur, 16× tibia, 4× femur and tibia).

CONCLUSIONS

The results of the presented study indicate that intraoperative fluoroscopy allows to identify non-accurate tunnel positions regarding to radiological criteria. The determined low variability indicates that fluoroscopic-based ACL reconstruction can be recommended as a feasible, easy and effective adjunct that enables surgeons to create more consistent and reliable tunnel positions in ACL reconstruction.

LEVEL OF EVIDENCE

IV.

Variability of landmark acquisition affects tunnel calculation in image-free ACL navigation

PURPOSE

The purpose of this study was to determine the inter- and intraobserver variability of intraarticular landmark identification for tunnel position calculation in image-free anterior cruciate ligament (ACL) navigation.

METHODS

In a test/retest scenario, thirteen experienced ACL surgeons (>50 reconstructions year) experienced in image-free ACL navigation were asked to identify the landmarks required for image-free ACL navigation in the same cadaver knee. Landmark positions were registered using a fluoroscopic ACL navigation system. Positions were determined using validated radiological measurement methods. For variability analysis, mean positions, deviations between the test/retest positions, standard deviations (SD) and range were calculated.

RESULTS

Interobserver analysis showed a mean variability (SD) for the tibial landmark positions of 3.0 mm with deviations of up to 24.3 mm (range). Mean femoral landmark variability was 2.9 mm (SD) with deviations of up to 11.3 mm (range). Intraobserver analysis showed a tibial reproducibility of 2.2 mm (SD 2.0 mm; range 10.9 mm) and a femoral of 1.9 mm (SD 1.9 mm; range 10.4 mm).

CONCLUSION

The data of the presented study suggest that a considerable inter- and intraobserver variability in intraarticular landmark identification exists. Reasonable ranges were found that have to be considered as a potential risk for miscalculation of tunnel positions in image-free ACL reconstruction.

CLINICAL RELEVANCE

Landmark acquisition affects tunnel calculation in image-free ACL.

LEVEL OF EVIDENCE

IV.

Risk for Revision After Anterior Cruciate Ligament Reconstruction Is Higher Among Adolescents: Results From the Danish Registry of Knee Ligament Reconstruction

Background:

The number of children and adolescents with anterior cruciate ligament (ACL) reconstructions is increasing, and disturbing reports on high rerupture rates in this group have been noted.

Purpose:

To describe the outcome of ACL reconstruction in children and adolescents based on data from the Danish Knee Ligament Reconstruction Registry (DKRR).

Study Design:

Cohort study; Level of evidence, 3.

Methods:

Data were retrieved from the DKRR, a national population-based registry. The analysis was based on a population of 14,806 ACL-reconstructed patients. The outcome was evaluated using risk of ACL revision, subjective outcome score (Knee injury and Osteoarthritis Outcome Score [KOOS]), Tegner function score, and objective knee laxity. Three age groups were defined (A, <13 years; B, 13-15 years; and C, 15-20 years) and compared with D, patients ≥20 years (adults). There were 95 patients in group A, 327 in B, 2888 in C, and 11,496 in D.

Results:

There was a significantly increased risk of revision surgery in the age groups B (6.7%) and C (4.9%) compared with the adults in group D (2.0%). Objective knee laxity did not differ between the 4 groups. Groups A, B, and C had a higher score on the combined KOOS symptoms, pain, sport, and quality of life subscales (KOOS4; 79.6, 76.6, and 73.1, respectively) compared with the adults (69.7). Group B had higher KOOS quality of life (76.6) and sports (71.1) scores than did group C (73.1 and 66.4, respectively). The Tegner activity score did not differ between the 4 groups. No impact of the use of extracortical graft fixation was detected in the youngest age group.

Conclusion:

Study results indicated an increased risk of graft failure in patients between 13 and 20 years of age. This is in contrast to the better subjective and equal objective knee score found in the same age groups.

Clinical Relevance:

The new knowledge about the high revision rate among ACL-reconstructed teenagers is important for evidence-based preoperative information of ACL patients and their parents.

Proximal Tibial Anterior Closing Wedge Osteotomy in Repeat Revision of Anterior Cruciate Ligament Reconstruction

BACKGROUND

Physicians should consider an increased posterior tibial slope (PTS) as a risk factor for graft failure when proposing anterior cruciate ligament (ACL) re-revision.

PURPOSE

To describe the surgical technique of combined ACL revision and proximal tibial anterior closing wedge osteotomy and to evaluate its clinical outcome in cases of recurrent graft failure with associated increased tibial slope.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Between 2008 and 2010, 5 combined ACL re-revisions with proximal tibial anterior closing wedge osteotomy were retrospectively evaluated after a mean 31.6 months' follow-up (range, 23-45 months). All patients reported subjective knee instability preoperatively and demonstrated increased laxity on physical examination. Intrinsic risk factors for graft failure (excessive tibial slope) were identified in all cases. Preoperative and postoperative functional assessments included the International Knee Documentation Committee (IKDC) score along with the Lysholm score and Tegner activity scale.

RESULTS

The mean Lysholm score was 46.2 preoperatively (range, 26-69) and 87.8 (range, 60-100) postoperatively. The mean IKDC subjective score was 39.5 (range, 21.8-64.4) before surgery and 79.1 (range, 48.3-98.9) at the last follow-up. The mean Tegner activity score was 7.4 (range, 5-9) before the latest ACL injury and 7.2 (range, 5-9) at the last follow-up. The mean PTS was 13.6° (range, 13°-14°) preoperatively and 9.2° (range, 8°-10°) postoperatively (P = .0005). The mean differential anterior laxity was 10.4 mm (range, 8-14 mm), and this significantly decreased to 2.8 mm (range, 2-4 mm) at the last follow-up. Using the Kellgren-Lawrence classification to evaluate the presence of arthritis, 1 patient was grade 1, 3 patients were grade 2, and 1 patient was grade 3.

CONCLUSION

Combined ACL re-revision with proximal tibial anterior closing wedge osteotomy restores knee stability and function with satisfactory clinical outcomes in patients who experience recurrent ACL ruptures with an associated increased PTS.

Prevalence and Incidence of Cartilage Injuries and Meniscus Tears in Patients Who Underwent Both Primary and Revision Anterior Cruciate Ligament Reconstructions

BACKGROUND

Previous studies have found differences in meniscus and cartilage injury rates between groups of patients after primary and revision anterior cruciate ligament reconstructions (ACLRs). This study examined a cohort of individual patients who underwent primary and subsequent revision ACLR to determine the incidence of cartilage and meniscus disease.

PURPOSE

To describe the prevalence and incidence of meniscus and articular cartilage injuries in patients who underwent primary and then subsequent revision ACLR as well as indicate differences in the management of these injuries.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent primary and then revision ACLR from February 2005 to September 2011 were identified using a community-based registry. Patient and procedure characteristics were obtained, and descriptive statistics were used to evaluate the study sample.

RESULTS

There were 261 patients who underwent primary and then subsequent revision ACLR during the study period. The median age was 18 years at primary ACLR and 20 years at revision ACLR. Revision ACLR was performed for instability in 256 patients (98%) and for infection in 5 patients (2%). The prevalence of cartilage injuries increased from 14.9% at primary ACLR to 31.8% at revision ACLR. The prevalence of meniscus tears decreased from 54.8% at primary ACLR to 43.7% at revision ACLR. The prevalence of lateral meniscus tears was 32.2% at primary ACLR but only 18.4% at revision ACLR, while the prevalence of medial meniscus tears was the same at primary and revision ACLRs (32.6%). Patients who underwent meniscus tear treatment at primary ACLR had a 70.8% prevalence of meniscus tears at revision ACLR.

CONCLUSION

In this community-based sample followed from primary ACLR to revision ACLR, the prevalence of articular cartilage injuries increased, while the prevalence of meniscus injuries decreased. The higher prevalence of articular cartilage injuries at revision ACLR may represent new injuries. The lower prevalence of meniscus tears at revision ACLR may be caused by susceptible menisci being injured and treated at primary surgery or by changes in knee kinematics or injury exposure patterns.

A Radiographic Assessment of Failed Anterior Cruciate Ligament Reconstruction: Can Magnetic Resonance Imaging Predict Graft Integrity?

BACKGROUND

Magnetic resonance imaging (MRI) showing an "intact" anterior cruciate ligament (ACL) graft may not correlate well with examination findings. Reasons for an ACL graft dysfunction may be from malpositioned tunnels, deficiency of secondary stabilizers, repeat injuries, or a combination of factors.

PURPOSE

To evaluate the concordance/discordance of an ACL graft assessment between an arthroscopic evaluation, physical examination, and MRI and secondarily to evaluate the contributing variables to discordance.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 50 ACL revisions in 48 patients were retrospectively reviewed. The ACL graft status was recorded separately based on Lachman and pivot-shift test data, arthroscopic findings from operative reports, and MRI evaluation and was categorized into 3 groups: intact, partial tear, or complete tear. Two independent evaluators reviewed all of the preoperative radiographs and MRI scans, and interrater and intrarater reliability were evaluated. Concordance and discordance between a physical examination, arthroscopic evaluation, and MRI evaluation of the ACL graft were calculated. Graft position and type, mechanical axis, collateral ligament injuries, chondral and meniscal injuries, and mechanism of injury were evaluated as possible contributing factors using univariate and multivariate analyses. Sensitivity and specificity of MRI to detect a torn ACL graft and meniscal and chondral injuries on arthroscopic evaluation were calculated.

RESULTS

The interobserver and intraobserver reliability for the MRI evaluation of the ACL graft were moderate, with combined κ values of .41 and .49, respectively. The femoral tunnel position was vertical in 88% and anterior in 46%. On MRI, the ACL graft was read as intact in 24%; however, no graft was intact on arthroscopic evaluation or physical examination. The greatest discordance was between the physical examination and MRI, with a rate of 52%. An insidious-onset mechanism of injury was significantly associated with discordance between MRI and arthroscopic evaluation of the ACL (P = .0003) and specifically with an intact ACL graft on MRI (P = .0014). The sensitivity and specificity of MRI to detect an ACL graft tear were 60% and 87%, respectively.

CONCLUSION

Caution should be used when evaluating a failed ACL graft with MRI, especially in the absence of an acute mechanism of injury, as it may be unreliable and inconsistent.

Revision of anterior cruciate ligament reconstruction with allografts in patients younger than 40 years old: a 2 to 4 year results

PURPOSE

The purpose of this study is first to report the outcomes, at 4 years follow-up, in revision ACL surgery using allografts in patients younger than 40 years old, and then compared soft tissue allografts to bone tendon allografts.

METHODS

This retrospective study included 47 patients who underwent ACL revision surgery with fresh-frozen allografts. Patellar tendon allograft or tibialis anterior allograft was used. Twenty-seven patients undergoing ACL revision with patellar tendon allograft were compared retrospectively with twenty-two patients undergoing the same procedure with soft tissue tibialis anterior allograft. Lysholm, IKDC, and KT-1000 values were obtained preoperatively and postoperatively.

RESULTS

The average patient follow-up was 4.6 years (±2.5). The mean age at time of the revision was 34 years old (±6.3). Overall, patients reported the overall condition of their knee as excellent or good in 85% of the patients (10 excellent, 33 good). Based on their experience, 85% would have the surgery again if they had the same problem in the other knee. Both subgroups experienced significant improvement in Lysholm, IKDC, and KT-1000 values, with no difference found between groups at final follow-up.

CONCLUSION

Revision ACL with allografts has excellent and good results in 85% of patients younger than 40 years old. No statistical difference was seen between soft tissue (tibialis anterior) and patellar tendon allograft.

LEVEL OF EVIDENCE

IV.

[Anatomic reconstruction of the anterior cruciate ligament with the autologous quadriceps tendon. Primary and revision surgery]

OBJECTIVE

Restore function of the anterior cruciate ligament (ACL).

INDICATIONS

Chronic functional instability with rupture of the ACL, giving way phenomena, acute rupture of the ACL with concomitant meniscus repair, rerupture of ACL graft with anatomical tunnels.

CONTRAINDICATIONS

Local infection of the skin at the knee joint, local soft tissue damage, after rupture of the quadriceps tendon, enthesopathia of the quadriceps tendon, lack of patient compliance.

SURGICAL TECHNIQUE

Harvest quadriceps tendon graft with a bone block via a 4-5 cm long incision, starting from the middle third of the proximal patella pole without damaging the tendon fibers. Drill the femoral tunnel via a deep anteromedial portal with the knee flexed of more than 110° (tunnel diameter 0.5-1 mm smaller in diameter than bone block). Gentle tunnel preparation using dilators. In absence of an ACL stump the lateral meniscus anterior horn serves as tibial landmark. In case of revision surgery, remove graft material and implants from the tunnel. Graft fixation using press fit method in the femoral tunnel. Tibial graft fixation archieved with a resorbable interference screw and a button.

POSTOPERATIVE MANAGEMENT

Goal of the inflammatory phase (weeks 1-2) is pain and inflammation control (20 kg partial weight bearing). During the proliferative phase (weeks 2-6), load and mobility slowly increased (closed-chain exercises). During the remodeling phase (> 6 weeks), strength and coordination exercises are performed. In revision cases and in case of concomitant injuries, longer partial weight-bearing period might be necessary. Athletes should not return to competitive sports before 6-8 months.

RESULTS

In a prospective study, 33 patients (age 16-48 years) were examined after replacement of the ACL with a quadriceps tendon graft after a minimum follow-up (FU) of 2 years (12 revision; 21 primary surgery). No post- or perioperative complications. Postoperative radiographs showed an anatomical tunnel location and no dislocation of the bone block. After 2 years the difference of a-p translation compared to the other leg was assessed by the use of KT 1000. The revision group improved from an average of 7.2 mm (pre-op) to 2.2 mm (FU). The group with primary surgery improved from 6.4 mm (pre-op) to 1.7 mm (FU). A sliding pivot shift phenomenon was detected in 2 patients in the revision group and 1 patient in the primary surgery group.

Use of a fluoroscopic overlay to assist arthroscopic anterior cruciate ligament reconstruction

BACKGROUND

A growing body of evidence supports the importance of anatomic tunnel positioning in the success of anterior cruciate ligament (ACL) reconstruction, which stimulates the need for technologies to aid surgeons in achieving accurate anatomic tunnel placement. Intraoperative fluoroscopy is potentially one such technology, while its efficacy and usability have yet to be established.

PURPOSE

To investigate the performance of an intraoperative fluoroscopic overlay in guiding tunnel placement during ACL reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twenty cadaveric knees underwent computed tomography (CT) scans and arthroscopic digitization of ACL insertion sites. The outlines of the digitized insertion sites were mapped to the corresponding CT-acquired bone models through a co-registration procedure. Twenty orthopaedic surgeons performed simulated ACL reconstructions, each on a randomly assigned cadaveric knee, first without and then with the aid of a fluoroscopic overlay system. The overlay system displayed on a lateral fluoroscopic image targets points representing the locations of the ACL insertion sites estimated from the literature data. Surgeons were allowed to adjust their tunnel positions under the guidance of the fluoroscopic image. Their initial, intermediate, and final positions were documented and compared with the target points as well as the native insertion sites.

RESULTS

Surgeons demonstrated significant (P < .01) improvements in femoral and tibial tunnel placements relative to the target points from an average distance of 3.9 mm to 1.6 mm on the femur and 2.1 mm to 0.9 mm on the tibia. The improvements toward the knee-specific actual insertion sites were significant on the tibial side but not on the femoral side.

CONCLUSION

Surgeons can be successfully guided with fluoroscopy to create more consistent femoral and tibial tunnels during ACL reconstruction. More research is warranted to develop better population representations of the locations of natural insertion sites.

CLINICAL RELEVANCE

Intraoperative fluoroscopy can be an effective, easy, and safe method for improving tunnel positioning during ACL reconstruction.

Differences in mechanisms of failure, intraoperative findings, and surgical characteristics between single- and multiple-revision ACL reconstructions: a MARS cohort study

BACKGROUND

The factors that lead to patients failing multiple anterior cruciate ligament (ACL) reconstructions are not well understood.

HYPOTHESIS

Multiple-revision ACL reconstruction will have different characteristics than first-time revision in terms of previous and current graft selection, mode of failure, chondral/meniscal injuries, and surgical charactieristics.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

A prospective multicenter ACL revision database was utilized for the time period from March 2006 to June 2011. Patients were divided into those who underwent a single-revision ACL reconstruction and those who underwent multiple-revision ACL reconstructions. The primary outcome variable was Marx activity level. Primary data analyses between the groups included a comparison of graft type, perceived mechanism of failure, associated injury (meniscus, ligament, and cartilage), reconstruction type, and tunnel position. Data were compared by analysis of variance with a post hoc Tukey test.

RESULTS

A total of 1200 patients (58% men; median age, 26 years) were enrolled, with 1049 (87%) patients having a primary revision and 151 (13%) patients having a second or subsequent revision. Marx activity levels were significantly higher (9.77) in the primary-revision group than in those patients with multiple revisions (6.74). The most common cause of reruptures was a traumatic, noncontact ACL graft injury in 55% of primary-revision patients; 25% of patients had a nontraumatic, gradual-onset recurrent injury, and 11% had a traumatic, contact injury. In the multiple-revision group, a nontraumatic, gradual-onset injury was the most common cause of recurrence (47%), followed by traumatic noncontact (35%) and nontraumatic sudden onset (11%) (P < .01 between groups). Chondral injuries in the medial compartment were significantly more common in the multiple-revision group than in the single-revision group, as were chondral injuries in the patellofemoral compartment.

CONCLUSION

Patients with multiple-revision ACL reconstructions had lower activity levels, were more likely to have chondral injuries in the medial and patellofemoral compartments, and had a high rate of a nontraumatic, recurrent injury of their graft.

Technique of anatomical footprint reconstruction of the ACL with oval tunnels and medial portal aimers

PURPOSE

The purpose of this article was to demonstrate an anterior cruciate ligament (ACL) reconstruction technique using oval tunnels. Aim of this single bundle technique is to fit the footprint anatomy of the ACL as closely as possible. TECHNIQUE AND PATIENTS: The presented technique is a single bundle technique using a semitendinosus graft. For femoral tunnel placement, a specific medial portal aimer (Karl Storz, Tuttlingen, Germany) is used. Aiming and drilling of the femoral tunnel are performed via the medial portal. Oval tunnels are created by stepwise dilatation with ovally shaped dilatators. The position of the femoral tunnel is visualized and controlled with the arthroscope via the medial portal. For the tibial tunnel placement, a specific aimer was used as well. With this technique, 24 patients were operated and all intra- and postoperative complications were analyzed prospectively. The tunnel position was documented postoperatively by CT scan.

RESULTS

There were no significant intra- and postoperative complications associated with the oval tunnel technique. The postoperative 3D CT scan revealed that all femoral and tibial tunnels were located within the area of the anatomical ACL insertions.

CONCLUSIONS

This article presents an ACL reconstruction technique using oval dilatators and medial portal aimers to create oval tunnels. These oval tunnels match the insertion site anatomy much closer than round tunnels do.

LEVEL OF EVIDENCE

Level IV, case series.

Single photon emission computerized tomography and conventional computerized tomography (SPECT/CT) for evaluation of patients after anterior cruciate ligament reconstruction: a novel standardized algorithm combining mechanical and metabolic information

PURPOSE

The purpose of this study was to introduce a novel standardized algorithm using SPECT/CT, which promises the potential combined assessment of the biology of the joint in particular the bone-graft-fixation complex and the 3D tunnel placement in patients after ACL reconstruction. Its clinical application and inter- and intra-observer reliability should be critically evaluated.

METHODS

A novel SPECT/CT localization scheme consisting of 13 tibial, 9 femoral and 4 patellar regions on standardized axial, coronal and sagittal slices is proposed. The tracer activity on SPECT/CT was localized and recorded in 25 consecutive patients using a 3D volumetric and quantitative analysis software. The inter- and intra-observer reliability was assessed for localization and tracer activity. The tunnel position was assessed in 3D-CT using standardized frames of reference. The inter- and intra-observer reliability (OR) of the measured distances were calculated (ICC).

RESULTS

The localization scheme for tracer uptake analysis was useful and easily applicable in all 25 knees. It showed very high inter-OR and intra-ORs for all regions (ICC > 0.80). Tibial and femoral tunnel position measurements showed strong agreement between the readings of the two observers; the ICCs for the position, angulation, length and entry point of the femoral tunnel were >0.88 (intra-OR) and >0.86 (inter-OR). The ICC for the position of the tibial tunnel (angulation, length and entry point) was >0.79 (intra-OR) and >0.74 (inter-OR).

CONCLUSIONS

The SPECT/CT algorithm presented is highly reliable and clinically feasible. Combining the 3D-mechanical information on tunnel placement and attachment areas and the 3D metabolic data will be helpful in evaluating patients with pain after ACL reconstruction.

Current concept in rotational laxity control and evaluation in ACL reconstruction

Rotation combined with translation; compose the three-dimensional motion of the knee subluxation in anterior cruciate ligament deficient knee. The worldwide scientists were focused initially on the translation part of this complex 3D motion, but since the beginning of the century there was a large interest on knee rotational laxity study. Lot of paper reported new devices and results with an explosion since the beginning of the decade. The purpose of this review is to provide an extensive critical analysis of the literature and clarify the knowledge on this topic. We will start with a dismemberment of different rotational laxities reported: the rotation coupled with translation in 2D tests such as Lachman test and anterior drawer test; the rotational envelope considering the maximum internal external rotation; and the "active rotation" occurring in 3D Pivot-shift (PS) test. Then we will analyze the knee kinematics and the role of different anterior cruciate ligament (ACL) bundle on rotation. A review of different mechanical and radiological devices used to assess the different rotations on ACL deficient knees will be presented. Two groups will be analyzed, dynamic and static conditions of tests. Navigation will be described precisely; it was the starter of this recent interest in rotation studies. Opto electronic and electromagnetic navigation systems will be presented and analyzed. We will conclude with the last generation of rotational laxity assessment devices, using accelerometers, which are very promising.

SPECT/CT tracer uptake is influenced by tunnel orientation and position of the femoral and tibial ACL graft insertion site

PURPOSE

SPECT/CT is a hybrid imaging modality, which combines a 3D scintigraphy (SPECT) and a conventional computerised tomography (CT). SPECT/CT allows accurate anatomical localisation of metabolic tracer activity. It allows the correlation of surgical factors such as tunnel position and orientation with mechanical alignment, clinical outcome and biological factors. The purpose of this study was to investigate whether the SPECT/CT tracer uptake (intensity and distribution) correlates with the stability and laxity of the knee joint and the position and orientation of the tibial and femoral tunnels in patients after anterior cruciate ligament (ACL) reconstruction.

METHODS

A consecutive series of knees (n=66), with symptoms of pain and/or instability after ACL reconstruction were prospectively evaluated using clinical examination and 99mTc-HDP-SPECT/CT. Clinical laxity testing was performed using the Rolimeter (Ormed, Freiburg, Germany) including Lachman testing (0-2 mm, 3-5 mm, 6-10 mm, >10 mm), anterior drawer test (0-2 mm, 3-5 mm, 6-10 mm, >10 mm), pivot shift test (positive versus negative) and patient-based subjective instability (yes versus no). For analysis of SPECT/CT tracer uptake a previously validated SPECT/CT localisation scheme consisting of 17 tibial, nine femoral and four patellar regions on standardised axial, coronal, and sagittal slices was used. The tracer activity on SPECT/CT was localised and recorded using a 3D volumetric and quantitative analysis software. Mean, standard deviation, minimum and maximum of grading for each area of the localisation scheme were recorded. The position and orientation of the tibial and femoral tunnel was assessed using a previously published method on 3D-CT.

RESULTS

Correlation of instability, pivot shift as well as clinical laxity testing with 99mTc-HDP-SPECT/CT tracer uptake intensity and distribution showed no significant correlation. 99mTc-HDP-SPECT/CT tracer uptake correlated significantly with the position and orientation of the ACL graft. A more horizontal femoral graft position showed significantly increased tracer uptake within the superior and posterior femoral regions. A more posteriorly-placed femoral insertion site showed significantly more tracer uptake within the femoral and tibial tunnel regions. A more vertical or a less medial tibial tunnel orientation showed significant increased uptake within the tibial and femoral tunnel regions. A more anterior tibial tunnel position showed significantly more tracer uptake in the femoral and tibial tunnel regions as well as the entire tibiofemoral joint.

CONCLUSIONS

SPECT/CT tracer uptake intensity and distribution showed a significant correlation with the femoral and tibial tunnel position and orientation in patients with symptomatic knees after ACL reconstruction. No correlation was found with stability or clinical laxity. SPECT/CT tracer uptake distribution has the potential to give us important information on joint homeostasis and remodelling after ACL reconstruction. It might help to predict ACL graft failure and improve our surgical ACL reconstruction technique in finding the optimal tunnel and graft position and orientation.

Revision anterior cruciate ligament reconstruction: an update

With the rising number of anterior cruciate ligament (ACL) reconstructions performed, revision ACL reconstruction is increasingly common nowadays. A broad variety of primary and revision ACL reconstruction techniques have been described in the literature. Recurrent instability after primary ACL surgery is often due to non-anatomical ACL graft reconstruction and altered biomechanics. Anatomical reconstruction must be the primary goal of this challenging revision procedure. Recently, revision ACL reconstruction has been described using double bundle hamstring graft. Successful revision ACL reconstruction requires an exact understanding of the causes of failure and technical or diagnostic errors. The purpose of this article is to review the causes of failure, preoperative evaluation, graft selection and types of fixation, tunnel placement, various types of surgical techniques and clinical outcome of revision ACL reconstruction.

Revision ACL reconstruction: influence of a lateral tenodesis

PURPOSE

The aims of this article were to report the objective results of revision ACL reconstruction and to assess the influence of an associated lateral extra-articular tenodesis on knee stability and IKDC score.

METHODS

This study focused on revision ACL reconstruction and was conducted over a 10-year period, from 1994 to 2003 with ten French orthopedic centers participating. The minimum follow-up required was 2 years. To be included, patients had to be evaluated at follow-up with the objective International Knee Documenting Committee (IKDC) scoring system. In 2006, 163 patients met the inclusion criteria.

RESULTS

The objective IKDC knee score improved significantly after revision ACL reconstruction, with 72% IKDC A + B (26% A). When a lateral tenodesis was performed, 80% had a negative pivot shift, versus 63% without (P = 0.03), but there was no significant difference in the IKDC score.

CONCLUSION

This study shows a significant improvement in the IKDC score after revision ACL reconstruction. The association of a lateral extra-articular tenodesis with the intra-articular graft increases knee stability after revision ACL reconstruction; however, this additional procedure does not significantly alter the IKDC score at follow-up.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

A CT-based classification of prior ACL femoral tunnel location for planning revision ACL surgery

PURPOSE

The purposes of this study are to describe an ACL femoral tunnel classification system for use in planning revision ACL reconstruction based on 3-D computed tomography (CT) reconstructions and to evaluate its inter- and intra-rater reliability.

METHODS

A femoral tunnel classification system was developed based on the location of the femoral tunnel relative to the lateral intercondylar ridge. The femoral tunnel was classified as Type I if it was located entirely below and posterior to the ridge as viewed from distally, Type II if it was slightly malpositioned (either vertically, anteriorly, or both), and Type III if it was significantly malpositioned. To evaluate the reproducibility of the classification system, CT scans of 27 knees were obtained from patients scheduled for revision ACL reconstruction, and 3-D reconstructions were created. Four views of the 3-D reconstruction of each femur were then obtained, and inter- and intra-observer reliability was determined following classification of the tunnels by eight observers.

RESULTS

Twenty-five tunnels were classified as Type I (5 tunnels), Type II (9 tunnels), or type III (11 tunnels) by at least 5 of 8 observers, while insufficient agreement was noted to classify two tunnels. The interobserver reliability of tunnel classification as type I, II, or III yielded a κ coefficient of 0.57, while intra-observer reliability yielded a κ coefficient of 0.67. Subclassification of type II femoral tunnels into the subgroups anterior, vertical, and both was possible in four of the nine type II patients. The interobserver reliability of the complete classification system yielded a κ coefficient of 0.50, while the intra-observer reliability yielded a κ coefficient of 0.54.

CONCLUSION

Classification of the location of ACL femoral tunnels utilizing 3-D reconstructions of CT data yields moderate to substantial inter- and intra-observer reliability.

LEVEL OF EVIDENCE

Diagnostic Level III.

Incidence and outcome after revision anterior cruciate ligament reconstruction: results from the Danish registry for knee ligament reconstructions

BACKGROUND

Revision anterior cruciate ligament (ACL) reconstruction is poorly described because of its rare incidence and mainly small case series presented in the literature. The Danish ACL reconstruction registry has monitored the development in revision ACL reconstruction since 2005.

HYPOTHESIS

We hypothesized that younger patients had a higher risk of revision ACL reconstruction than older patients and that subjective clinical outcome was worse after revision ACL reconstruction than after primary ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

All clinics performing ACL reconstructions in Denmark report to the national ACL reconstruction registry. The revision rate after primary ACL reconstruction (n = 12,193 procedures) and re-revision rate after revision ACL reconstruction (n = 1099 procedures) were calculated for the period of 2005 to 2010. Outcome at 1-year follow-up for the revision cohort was reported using the Knee Injury and Osteoarthritis Outcome Score (KOOS), Tegner function score, and objective knee stability measurement.

RESULTS

The rate of revision ACL reconstruction was 4.1% after 5 years. Revision occurred most frequently after 1 to 2 years. Patients below 20 years of age at the time of primary ACL reconstruction had a higher risk of revision (8.7%) than did patients older than 20 years of age (2.8%) (adjusted relative risk, 2.58; 95% confidence interval, 2.02-3.30). The KOOS scores 1 year after revision ACL reconstruction (mean ± standard deviation) were 73 ± 18 for symptoms, 78 ± 17 for pain, 84 ± 16 for activities of daily living, 52 ± 28 for sports, and 48 ± 21 for quality of life. All these scores were significantly lower than for primary ACL reconstruction: 77 ± 17 for symptoms, 84 ± 15 for pain, 89 ± 13 for activities of daily living, 62 ± 25 for sports, and 59 ± 21 for quality of life. Side-to-side difference in knee laxity improved from 5.8 mm before revision ACL reconstruction to 1.9 mm 1 year after revision ACL surgery. The use of allograft tissue for the revision procedure resulted in a higher risk of re-revision than did autograft tissue (relative risk, 2.05; 95% confidence interval, 1.5-2.4) (P < .01). The rate of re-revision after 5 years was 5.4%.

CONCLUSION

In this observational population-based study, the 5-year revision ACL reconstruction rate was 4.1%. Despite achieving acceptable knee stability after revision ACL reconstruction, subjective outcome is less favorable than after primary ACL reconstruction.

Prospective analysis of failure rate and predictors of failure after anatomic anterior cruciate ligament reconstruction with allograft

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction is one of the most frequently performed orthopaedic procedures. Failures are a reality of surgery; to limit failures, we must first understand and quantify them.

PURPOSE

The purposes of this study were to determine the rate and factors associated with graft failure after anatomic ACL reconstruction performed with allograft.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

All consecutive subjects who underwent anatomic single- or double-bundle ACL reconstruction with allograft between January 2007 and December 2009 were included and followed clinically. Graft failure was defined as patient-reported instability, pathological laxity during the physical examination, or evidence of a failed graft on magnetic resonance imaging or during arthroscopy. Potential predictors of graft failure that were explored included subject age, sex, height, weight, body mass index, meniscus injury, and time of return to preinjury sports.

RESULTS

There were 206 subjects included in this study: 168 double-bundle and 38 single-bundle reconstructions. Overall, 27 (13%) subjects experienced graft failure. Twenty-three (13%) double-bundle subjects failed. The characteristics associated with double-bundle graft failure were younger age (19 vs 25 years, P < .001) and earlier return to sports (at 222 vs 267 days, P = .007). Four (11%) of the single-bundle subjects failed. The characteristics associated with single-bundle graft failure were younger age (19 vs 24 years, P = .049) and increased body mass (83 vs 65 kg, P = .031).

CONCLUSION

The overall graft failure rate after anatomic ACL reconstruction with allograft was 13%. Younger age, earlier return to sports, and a higher body weight were associated with graft failure.

Surgical technique: revision ACL reconstruction with a rectangular tunnel technique

BACKGROUND

We developed the rectangular tunnel ACL reconstruction (RT ACLR) using a 10-mm wide bone-patellar tendon-bone (BTB) graft through rectangular tunnels with a rectangular aperture to reduce tunnel size: the cross-sectional area of the tunnels of 50 mm(2) (5 × 10 mm) in RT ACLR is less than that of 79 mm(2) in a conventional 10-mm round tunnel technique presuming the technique would be more suitable in revision ACLR with previous improperly placed tunnels.

DESCRIPTION OF TECHNIQUE

Two contiguous 5-mm tunnels inside the anatomic ACL femoral and tibial attachment areas along their long axes, and they are expanded with a 5 × 10-mm dilator into parallelepiped ones.

PATIENTS AND METHODS

We indicated and intended to perform the RT ACLR procedure in 31 patients requiring revision between 2004 and 2008. Eighteen of the 31 patients treated with the procedure were followed a minimum of 24 months (mean, 38 months; range, 24 to 73 months). We evaluated ROM, obtained IKDC scores, and determined stability with KT-1000.

RESULTS

The procedure could be applied in 30 of the 31 cases. One of the 18 reruptured the graft at 28 months. Of the remaining 17 patients with followup of 24 months or longer, 15 had full ROM, while the remaining two lost 5° of flexion; 11 were classified as normal and six were nearly normal according to the IKDC evaluation. Stability measured with KT-1000 was 1.0 ± 1.5 mm.

CONCLUSION

The RT ACLR technique provided acceptable results after one-stage revision ACLR.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Medium to long-term follow-up after ACL revision

PURPOSE

The aim of the present study is to present epidemiology and clinical outcome after revision anterior cruciate ligament (ACL) reconstruction with an intermediate follow-up time of up to 9 years.

METHODS

A retrospective study of patients treated with ACL revision from 2001 to 2007 at a university referral clinic was conducted. Study follow-up was performed in 2010; this follow-up included objective IKDC scores, KOOS, Tegner and SANE subjective scores, KT-1000 knee laxity measurements and registration of reoperations and complications.

RESULTS

One hundred and twenty-eight patients were available for follow-up. Median follow-up time was 6 (2-9) years. Mean age was 32 years, 50% were men. Eleven percent required staged procedures, 30% were reconstructed with allograft tendons and 23% had collateral ligament reconstruction in combination with the ACL revision. SANE knee global score (0-100) was 74 at follow-up, KOOS sub-scores were preoperatively 66, 69, 77, 42 and 39 for pain, symptoms, activity of daily living, sports and quality of life, respectively. At follow-up, scores were 70, 76, 81, 50 and 50, respectively. Sport and quality of life scores increased significantly. KT-1000 was 6.2 mm preoperatively and 2.5 at follow-up (P < 0.05). Six percent were re-revised and 2 patients had total knee replacements.

CONCLUSION

Despite objective findings of acceptable sagittal knee stability at follow-up, subjective outcome scores indicate significant knee impairment with low scores in sport and quality of life. A re-revision rate of 6% after 6 years is acceptable. It is imperative that patients eligible for ACL revision receive proper counseling in terms of outcome expectancies.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

Quadriceps muscle activation and radiographic osteoarthritis following ACL revision

PURPOSE

Quadriceps strength and activation may play an important role in the recovery from ACL revision surgery. The purpose of this study was to describe quadriceps strength and central activation ratio (CAR) and correlate with radiographic findings in patients with ACL revision surgery.

METHODS

Twenty-one patients who were on average 47.5 ± 21.1 months [range: 14-85 months] post-revision ACL reconstruction. We performed knee joint physical examination and radiographic evaluation. Quadriceps strength testing consisted of maximal voluntary isometric contractions (MVIC) with the knee bent to 90-degrees bilaterally. We calculated quadriceps central activation ratio using the superimposed burst technique. Radiographs (bilateral standing antero-posterior in knee flexion and lateral in full extension) were evaluated by a fellowship-trained orthopedic surgeon using the International Knee Documentation Committee (IKDC) grading system.

RESULTS

Mean CAR was 83.9 ± 12.0% on the reconstructed limb and 85.5 ± 9.5% on the contralateral limb. Average, normalized MVIC torque was 2.5 ± 1.0 Nm/kg on the reconstructed limb and 2.7 ± 1.0 N m/kg for the contralateral limb. Patient age at the time of follow-up evaluation was related to severity of knee joint degeneration, particularly the medial, anterior and patellofemoral compartments. Younger patients with lower CARs tended to have more severe degeneration in the patellofemoral joint. Older patients with lower normalized MVIC torque values tended to exhibit more severely graded degeneration in the patellofemoral joint.

CONCLUSION

Bilateral quadriceps central activation deficits and radiographic osteoarthritis are evident in patients with revision ACL reconstruction.