Revision anterior cruciate ligament reconstruction

Can graft choice affect return to sport following revision anterior cruciate ligament reconstruction surgery?

INTRODUCTION

With the increasing number of primary anterior cruciate ligament (ACL) reconstructions, revision surgery has become more frequent. The purpose of the present study is to retrospectively compare the clinical outcome of contralateral hamstring tendon autografts vs. allografts for ACL revision surgery, specifically with regard to patient satisfaction, return to preinjury activity level, and postoperative functional outcomes.

MATERIALS AND METHODS

Between 2004 and 2011, 59 patients underwent ACL revision surgery. 44 were successfully recontacted and retrospectively reviewed at an average follow-up of 5.2 years. 23 subjects underwent revision ACL reconstruction with contralateral autogenous hamstring tendon grafts; 21 underwent allograft revision ACL surgery. Clinical, arthrometric, and functional evaluations were performed. The Tegner, Knee Injury and Osteoarthritis Outcome Score (KOOS), International Knee Documentation Committee (IKDC) Subjective Knee Form were used. Objective evaluation included range of motion, Lachman test, pivot-shift test and KT-1000 instrumented laxity testing.

RESULTS

No major complications were reported. Follow-up examination showed that there were no significant differences IKDC and KOOS scores between the groups. The percentage of patients returning to pre-injury level was high in both groups. Anterior tibial translation according to manual laxity testing and as measured with KT-1000 arthrometer was not statistically different in the two groups. With regard to return to sports, patients undergoing revision surgery with autografts experienced a quicker return to sports compared to patients who underwent allograft revision surgery.

CONCLUSIONS

The use of contralateral hamstring tendon autografts for ACL revision surgery produced similar subjective and objective outcomes at 5.2 years follow-up compared to revision with allograft patellar or Achilles tendon. Patients undergoing revision surgery with autografts experienced a quicker return to sports compared to patients who underwent allograft revision surgery.

Outcome of arthroscopic single-bundle anterior cruciate ligament reconstruction: anteromedial portal technique versus transtibial drilling technique

PURPOSE

Controversies exist about the femoral tunnel preparation technique in anterior cruciate ligament (ACL) reconstruction surgeries. The aim of this study was to evaluate mid-term outcomes of transtibial (TT) technique in comparison with anteromedial portal (AMP) one.

METHODS

Demographic data, height, weight, period of time from injury to surgery, and follow-up duration of patients underwent ACL reconstruction using single-bundle hamstring graft by the senior author between 2007 and 2011 were evaluated, retrospectively. Mid-quadriceps circumference difference, passive range of motion of the joint, anterior drawer test, Lachman test, and pivot shift test were assessed for each case. Function of the knee joint was calculated using International Knee Documentation Committee (IKDC), Lysholm, and Tegner scores.

RESULTS

Of 50 cases in the AMP group (age 30.6 ± 6.5), 45 were male and of the 44 patients in the TT group (age 30.0 ± 6.5), forty were male. Mean follow-up times in the AMP and TT group were 18.2 months (range 12-84 months) and 25.7 months (range 16-48 months), respectively. No statistically significant difference was found in mid-quadriceps circumference difference (P = 0.861). Also, functional knee scores (P values of IKDC = 0.329, Lysholm score = 0.08, Tegner = 0.504) and stability tests (P values of anterior drawer test = 0.07, Lachman test = 0.486, pivot shift test = 0.348) did not differ statistically between groups.

CONCLUSION

There is no superiority of AMP technique on TT technique in ACL reconstructive surgeries. It could be suggested that performing a well-done technique, either TT or AMP, may be more important than only choosing a technique.

Study on the relationship between the thickness of the anterior cruciate ligament, anthropometric data and anatomical measurements on the knee

OBJECTIVES

To ascertain thickness measurements on the anterior cruciate ligament (ACL) in its middle third on magnetic resonance imaging (MRI) scans and to assess whether there is any association between variations in ligament thickness and patients' heights and ages, along with variations in the anatomical measurements on the knee.

METHODS

MRI scans on 48 knees were evaluated. The anteroposterior size of the femoral condyles, interepicondylar distance, intercondylar distance and anteroposterior and mediolateral thicknesses of the ACL were measured. It was assessed whether there was any statistical relationship between ACL thickness and the patients' age, height or other measurements evaluated.

RESULTS

The mean thickness of the middle third of the ACL was 4.5 mm in the sagittal plane and 4.3 mm in the frontal plane. The anteroposterior thickness of the ACL in its middle third had a positive relationship with the size of the lateral condyle. The mediolateral thickness of the ACL in its middle third had a positive relationship with the size of the lateral condyle and with the intercondylar distance in the axial plane. There was no relationship between the thickness of the ACL and the patients' age or height.

CONCLUSION

The thickness of the ACL presented positive associations with the size of the lateral femoral condyle and the intercondylar distance.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction: Bone Grafting Technique Using an Allograft Bone Matrix

Outcomes of primary anterior cruciate ligament (ACL) reconstruction have been reported to be far superior to those of revision reconstruction. However, as the incidence of ACL reconstruction is rapidly increasing, so is the number of failures. The subsequent need for revision ACL reconstruction is estimated to occur in up to 13,000 patients each year in the United States. Revision ACL reconstruction can be performed in one or two stages. A two-stage approach is recommended in cases of improper placement of the original tunnels or in cases of unacceptable tunnel enlargement. The aim of this study was to describe the technique for allograft ACL tunnel bone grafting in patients requiring a two-stage revision ACL reconstruction.

Technique of anatomical single bundle ACL reconstruction with rounded rectangle femoral dilator

BACKGROUND

This study aimed to present a new technique for anatomical single bundle anterior cruciate ligament (ACL) reconstruction. We developed an original rounded rectangular dilator set to create rounded rectangular femoral tunnels. This technique can increase the femoral tunnel size without roof impingement, and has the potential to reduce the graft failure rate. We investigated the tunnel position and the incidence of intraoperative complications.

METHOD

The presented technique is anatomical single bundle ACL reconstruction using a semitendinosus graft (with or without the gracilis tendon). The tunnel was drilled via an additional medial portal. Rounded rectangular tunnels were created using a special dilator. Tibial tunnels were created using conventional rounded tunnels. Fixation was achieved using a suspensory device on the femoral side and a plate and screw on the tibial side.

PATIENTS

Fifty patients underwent this surgery, and intraoperative complications were investigated. The femoral tunnel positions were documented postoperatively from computed tomography scans using the quadrant method. The tibial tunnel positions (anterior-to-posterior, medial-to-lateral) were documented using intraoperative X-ray scans.

RESULTS

Only one patient had a partial posterior tunnel wall blowout. The femoral tunnel length varied between 30 and 40mm (mean, 34.9±3.3mm). All femoral and tibial tunnels were located within the area of the anatomical ACL insertions.

CONCLUSION

We did not experience any serious intraoperative complications during anatomical single bundle ACL reconstruction using a rounded rectangle dilator, and the resulting locations of the femoral and tibial tunnels were within the anatomical ACL footprint.

LEVEL OF EVIDENCE

Level IV.

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.

Patient Outcomes and Predictors of Success After Revision Anterior Cruciate Ligament Reconstruction

Background:

Patient outcomes and predictors of success after revision anterior cruciate ligament (ACL) reconstruction are currently limited in the literature. Existing studies either have a small study size or are difficult to interpret because of the multiple surgeons involved in the care of the study sample.

Purpose:

To determine patient outcomes and predictors of success or failure after a single-stage revision ACL reconstruction by a single fellowship-trained senior surgeon at a single institution.

Study Design:

Case series; Level of evidence, 4.

Methods:

A total of 78 patients who underwent revision ACL reconstruction by a single surgeon from 2010 to 2014 were contacted and available for follow-up. The mean time from revision procedure to follow-up was 52 months. Those patients who were able to participate in the study sent in a completed Tegner activity level scale, International Knee Documentation Committee (IKDC) Subjective Knee Evaluation Form, and IKDC Current Health Assessment Form. The patients’ medical records were also thoroughly reviewed.

Results:

Five patients had subsequent failure after revision surgery. The median Tegner score was 6 at follow-up, and the mean subjective IKDC score was 72.5. There was no statistically significant difference in outcome scores when comparing revision graft type, body mass index, sex, need for bone grafting, and time from failure to revision. Patients with failures after primary ACL reconstruction secondary to a traumatic event were found to have statistically significantly higher IKDC scores (mean, 76.6) after revision when compared with nontraumatic failures (mean, 67.1), even when controlling for confounders (P < .017).

Conclusion:

Revision ACL reconstruction is effective in improving patient activity levels and satisfaction. However, the subjective IKDC results are quite variable and likely based on multiple factors. Patients with traumatic injuries contributing to graft failure after primary ACL reconstruction had a statistically significantly, although not clinically significant, higher IKDC score after revision surgery compared with nontraumatic failures. These data may be useful when counseling a patient on whether to pursue revision ACL reconstruction surgery.

Long-term clinical outcomes of combined BPTB ACL reconstruction and popliteus tendon plasty

PURPOSE

A deficiency of posterolateral structures significantly increases the varus load on the ACL, while a chronic ACL lesion, the increased tibial rotation and the repetitive non-physiological knee motion, could affect and damage the integrity of the popliteus tendon. Therefore, the aim of the present study was to report the very long clinical outcomes of a combined single-bundle BPTB ACL reconstruction and popliteus plasty according to Bousquets technique, for the treatment of combined chronic anterior and posterolateral laxities.

METHODS

Fifteen patients that underwent combined ACL reconstruction and popliteal plasty according to Bousquets technique were available at mean 26.8 ± 1.0 years (range 25.4-28.0 years). All the patients were evaluated clinically and 13 by means of KT-1000 Arthrometer as well. Subjective evaluation was performed with the subjective IKDC, WOMAC and a 0-10 VAS for pain scales.

RESULTS

At clinical evaluation, 10 patients (67 %) presented a negative anterior drawer test; Lachman test was negative in nine patients (60 %); the varus stress test was negative in eight (53 %); and the dial test was negative in all but one patient (93 %). Only two patients (15 %) presented a side-to-side difference >5 mm at the instrumented laxity evaluation.

CONCLUSION

The combined single-bundle BPTB ACL reconstruction and popliteal plasty according to Bousquets technique were able to produce very good long-term results, in terms of knee stability, subjective outcomes, functional results and return to sport activity, in case of chronic anterior and posterolateral laxities.

LEVEL OF EVIDENCE

Retrospective case series, Level IV.

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.

Length Changes of the Anterolateral Ligament During Passive Knee Motion: A Human Cadaveric Study

BACKGROUND

Persistent rotatory instability after anterior cruciate ligament (ACL) reconstruction may be a result of unaddressed insufficiency of the anterolateral structures. Recent publications about the anatomy of the anterolateral ligament (ALL) have led to a renewed interest in lateral extra-articular procedures, and several authors have proposed ALL reconstruction to supplement intra-articular ACL reconstruction. However, only limited knowledge about the biomechanical characteristics of the ALL exists.

PURPOSE/HYPOTHESIS

The purpose of this study was to analyze length changes of the ALL during passive knee motion. The study hypothesis was that the ALL lengthens with knee flexion and internal tibial rotation.

STUDY DESIGN

Controlled laboratory study.

METHODS

The ALL of 6 cadaveric knees was dissected. Specimens were mounted in a specifically designed test rig that allowed unconstrained passive flexion/extension movement between 0° and 90° as well as external/internal tibial rotation of 25° at various flexion angles. Highly elastic, capacitive polydimethylsiloxane strain gauges were attached to the insertion sites of the ALL. Length changes were recorded continuously at flexion angles between 0° and 90° and during internal/external tibial rotation at 0°, 15°, 30°, 45°, 60°, 75°, and 90°. All measurements were calculated as the relative length change (%) of the ALL compared with 0° of flexion and neutral rotation.

RESULTS

The mean relative length of the ALL significantly increased with increasing knee flexion (P < .001), with an estimated mean length change of +0.15% per degree. Both internal and external tibial rotation were independent determinants for length change; internal rotation significantly increased the length of the ALL (P < .001), whereas external rotation significantly decreased its length (P < .001). The mean length change with internal rotation increased with knee flexion, with a significantly greater length change at 90° compared with 0° (P = .048), 15° (P = .033), and 30° (P = .015). The maximum mean length change was +33.77% ± 9.62%, which was observed at 25° of internal rotation and 90° of flexion.

CONCLUSION

The ALL is a nonisometric structure that tensions with knee flexion and internal tibial rotation. Length changes with internal rotation were greater at higher flexion angles, with the greatest length change of the ALL observed at 90° of flexion.

CLINICAL RELEVANCE

The ALL can be considered a stabilizer against internal tibial rotation, especially at deep flexion angles. With regard to ALL reconstruction procedures, tensioning and fixation of the graft should be performed near 90° of flexion because graft tensioning near extension may cause excessive ligament strain with increasing knee flexion.

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.

How accurate are anatomic landmarks for femoral tunnel positioning in anterior cruciate ligament reconstruction? An in vivo imaging analysis comparing both anteromedial portal and outside-in techniques

PURPOSE

To assess the ability of 2 independent surgical techniques, an inside-out technique and an outside-in technique, using bony landmarks on the femoral wall, to place the anterior cruciate ligament graft anatomically.

METHODS

A retrospective single-center study was conducted in 2012 and included patients who underwent anterior cruciate ligament reconstruction. Two techniques were used: The lateral condylar wall was visualized from the anterolateral portal and tunnels were drilled "outside-in" in one group, whereas viewing was performed from the anteromedial portal and retrograde drilling ("inside-out") was performed in the other group. The primary outcome measure was the placement of the tunnel center point on postoperative computed tomography scans with 3-dimensional reconstruction, according to the radiographic quadrant method of Bernard and Hertel. The measurements were compared with optimal placements according to Bird et al. Their reliability was assessed with Spearman (rho) and intraclass correlation coefficients.

RESULTS

Forty patients were included, with 20 in each group; the mean age was 29.8 ± 9.6 years, and there were 33 men and 7 women. The interobserver reliability and intraobserver reliability of measurements were good, with a Spearman ρ between 0.46 (P = .002) and 0.93 (P < .001) and an intraclass correlation coefficient between 0.44 (P = .001) and 0.86 (P < .001). The femoral tunnel positions of both techniques were close to the previously published anatomic placements, but there was a significant difference between our results and the theoretical position in proximal-distal measurements (P = .01). There was no difference in the anteroposterior measurements. There was no statistical difference in the accuracy of placement of the femoral tunnel center point between these 2 independent techniques.

CONCLUSIONS

The direct arthroscopic visualization of bony landmarks seems sufficient for accurate positioning of the femoral tunnel whatever the drilling technique. This finding is clinically relevant because the routine use of direct measurement techniques or intraoperative radiographs may not be necessary to obtain anatomic tunnel placement.

LEVEL OF EVIDENCE

Level IV, case series.

Notchplasty in anterior cruciate ligament reconstruction in the setting of passive anterior tibial subluxation

PURPOSE

In an effort to minimize graft impingement among various ACL deficient states, we sought to quantitatively determine requirements for bone resection during notchplasty with respect to both volumetric amount and location.

METHODS

A validated method was used to evaluate Magnetic Resonance Imaging scans. We measured the ATT of the medial and lateral compartments in the following four states: intact ACL (27 patients), acute ACL disruption; <2 months post-injury (76 patients), chronic ACL disruption; 12 months post-injury (42 patients) and failed ACL reconstruction (75 patients). Subsequently, 11 cadaveric knees underwent Computed Tomography (CT) scanning. Specialized software allowed virtual anterior translation of the tibia according to the average ATT measured on MRI. Impingement volume was analyzed by performing virtual ACLRs onto the various associated CT scans. Location was analyzed by overlaying an on-screen protractor. The center of the notch was defined as 0°.

RESULTS

Average impingement volume changed significantly in the various groups compared to the intact ACL group (acute 577 ± 200 mm(3), chronic 615 ± 199 mm(3), failed ACLR 678 ± 210 mm(3), p=0.0001). The location of the required notchplasty of the distal femoral wall border did not change significantly. The proximal femoral border moved significantly towards the center of the notch (acute 8.6° ± 4.8°, chronic 7.8° ± 4.2° (p=0.013), failed ACLR 5.1° ± 5.9° (p=0.002)).

CONCLUSION

Our data suggests that attention should be paid peri-operatively to the required volume and location of notchplasty among the various ACL deficient states to minimize graft impingement.

Revision anterior cruciate ligament reconstruction

Context:

Reconstruction of the anterior cruciate ligament (ACL) is one of the most common surgical procedures, with more than 200,000 ACL tears occurring annually. Although primary ACL reconstruction is a successful operation, success rates still range from 75% to 97%. Consequently, several thousand revision ACL reconstructions are performed annually and are unfortunately associated with inferior clinical outcomes when compared with primary reconstructions.

Evidence Acquisition:

Data were obtained from peer-reviewed literature through a search of the PubMed database (1988-2013) as well as from textbook chapters and surgical technique papers.

Study Design:

Clinical review.

Level of Evidence:

Level 4.

Results:

The clinical outcomes after revision ACL reconstruction are largely based on level IV case series. Much of the existing literature is heterogenous with regard to patient populations, primary and revision surgical techniques, concomitant ligamentous injuries, and additional procedures performed at the time of the revision, which limits generalizability. Nevertheless, there is a general consensus that the outcomes for revision ACL reconstruction are inferior to primary reconstruction.

Conclusion:

Excellent results can be achieved with regard to graft stability, return to play, and functional knee instability but are generally inferior to primary ACL reconstruction. A staged approach with autograft reconstruction is recommended in any circumstance in which a single-stage approach results in suboptimal graft selection, tunnel position, graft fixation, or biological milieu for tendon-bone healing.

Strength-of-Recommendation Taxonomy (SORT):

Good results may still be achieved with regard to graft stability, return to play, and functional knee instability, but results are generally inferior to primary ACL reconstruction: Level B.

The epidemiology of revision anterior cruciate ligament reconstruction in Ontario, Canada

BACKGROUND

Knowledge of the rate of and risk factors for re-revision, reoperation, and readmission after revision anterior cruciate ligament reconstruction (ACLR) is limited.

PURPOSE

To determine the rate of and risk factors for re-revision, reoperation, and readmission after revision ACLR.

STUDY DESIGN

Descriptive epidemiology study.

METHODS

All patients who underwent first revision ACLR in Ontario, Canada, from January 2004 to December 2010 were identified and followed until December 2012. Exclusions included age <16 years, previous osteotomy, or multiligament knee reconstruction. The main outcome was re-revision ACLR. Secondary outcomes included reoperation (irrigation and debridement [I&D], meniscectomy, manipulation under anesthesia, contralateral ACLR, and total knee arthroplasty) and readmission. Survival to re-revision was determined using the Kaplan-Meier approach. A Cox proportional hazards model or logistic regression were used to determine the influence of patient, surgical, and provider factors on outcomes. A post hoc analysis was performed to determine the influence of the aforementioned factors on postoperative infection risk.

RESULTS

Overall, 827 patients were included (median age, 30 years; 58.8% males). Single-stage revisions comprised 92.9% of cases, and a meniscal procedure (repair or debridement) was performed in 45.3% of cases. The re-revision rate at a mean follow-up of 4.8 ± 2.2 years was 4.4%, and the 5-year survival rate was 95.4%. The rates of I&D, meniscectomy, contralateral ACLR, and readmission were 0.8%, 3.1%, 3.4%, and 4.1%, respectively. Manipulation under anesthesia and total knee arthroplasty were rare. Young age significantly increased contralateral ACLR risk (risk decreased by 5.1% with each year of age >16 years; P = .02) but not re-revision ACLR risk. Low surgeon's annual volume of revision ACLR (<4 revisions/year: odds ratio, 1.2; P = .02) and male sex (odds ratio, 13.3; P = .01) significantly increased overall infection risk; male sex also influenced I&D risk.

CONCLUSION

Re-revision, reoperation, and readmission rates after revision ACLR were low, and the risk for I&D, infection, and contralateral ACLR were influenced by male sex, low surgeon volume, and young age, respectively.

CLINICAL RELEVANCE

This is the first study to determine morbidity rates and risk factors after revision ACLR, providing reference data from the general population.

Effect of graft choice on the outcome of revision anterior cruciate ligament reconstruction in the Multicenter ACL Revision Study (MARS) Cohort

BACKGROUND

Most surgeons believe that graft choice for anterior cruciate ligament (ACL) reconstruction is an important factor related to outcome; however, graft choice for revision may be limited due to previously used grafts.

HYPOTHESES

Autograft use would result in increased sports function, increased activity level, and decreased osteoarthritis symptoms (as measured by validated patient-reported outcome instruments). Autograft use would result in decreased graft failure and reoperation rate 2 years after revision ACL reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Patients undergoing revision ACL reconstruction were identified and prospectively enrolled by 83 surgeons at 52 sites. Data collected included baseline demographics, surgical technique, pathologic abnormalities, and the results of a series of validated, patient-reported outcome instruments (International Knee Documentation Committee [IKDC], Knee injury and Osteoarthritis Outcome Score [KOOS], Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Marx activity rating score). Patients were followed up at 2 years and asked to complete the identical set of outcome instruments. Incidences of additional surgery and reoperation due to graft failure were also recorded. Multivariate regression models were used to determine the predictors (risk factors) of IKDC, KOOS, WOMAC, Marx scores, graft rerupture, and reoperation rate at 2 years after revision surgery.

RESULTS

A total of 1205 patients (697 [58%] males) were enrolled. The median age was 26 years. In 88% of patients, this was their first revision, and 341 patients (28%) were undergoing revision by the surgeon who had performed the previous reconstruction. The median time since last ACL reconstruction was 3.4 years. Revision using an autograft was performed in 583 patients (48%), allograft was used in 590 (49%), and both types were used in 32 (3%). Questionnaire follow-up was obtained for 989 subjects (82%), while telephone follow-up was obtained for 1112 (92%). The IKDC, KOOS, and WOMAC scores (with the exception of the WOMAC stiffness subscale) all significantly improved at 2-year follow-up (P < .001). In contrast, the 2-year Marx activity score demonstrated a significant decrease from the initial score at enrollment (P < .001). Graft choice proved to be a significant predictor of 2-year IKDC scores (P = .017). Specifically, the use of an autograft for revision reconstruction predicted improved score on the IKDC (P = .045; odds ratio [OR] = 1.31; 95% CI, 1.01-1.70). The use of an autograft predicted an improved score on the KOOS sports and recreation subscale (P = .037; OR = 1.33; 95% CI, 1.02-1.73). Use of an autograft also predicted improved scores on the KOOS quality of life subscale (P = .031; OR = 1.33; 95% CI, 1.03-1.73). For the KOOS symptoms and KOOS activities of daily living subscales, graft choice did not predict outcome score. Graft choice was a significant predictor of 2-year Marx activity level scores (P = .012). Graft rerupture was reported in 37 of 1112 patients (3.3%) by their 2-year follow-up: 24 allografts, 12 autografts, and 1 allograft and autograft. Use of an autograft for revision resulted in patients being 2.78 times less likely to sustain a subsequent graft rupture compared with allograft (P = .047; 95% CI, 1.01-7.69).

CONCLUSION

Improved sports function and patient-reported outcome measures are obtained when an autograft is used. Additionally, use of an autograft shows a decreased risk in graft rerupture at 2-year follow-up. No differences were noted in rerupture or patient-reported outcomes between soft tissue and bone-patellar tendon-bone grafts. Surgeon education regarding the findings of this study has the potential to improve the results of revision ACL reconstruction.

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.

Management of Combined Anterior Cruciate Ligament-Posterolateral Corner Tears: A Systematic Review

BACKGROUND

A consensus on the treatment of combined anterior cruciate ligament (ACL) and posterolateral corner (PLC) injuries is still lacking.

PURPOSE

To review the available literature on the management of these combined lesions to investigate the influence that injuries of knee posterolateral structures play in the outcome of an ACL lesion.

STUDY DESIGN

Systematic review; Level of evidence, 4.

METHODS

A comprehensive search was performed on PubMed, Medline, CINAHL, Cochrane, Embase, and Google Scholar databases using various combinations of the following keywords: "posterolateral corner," "plc," "posterolateral instability," "posterolateral injury," "anterior cruciate ligament," and "acl."

RESULTS

A total of 6 studies involving 95 patients were included. For those with PLC lesions, 14 patients were treated nonoperatively, 9 underwent an early anatomic repair, while the remaining 72 underwent a reconstruction. In all 95 patients, an ACL reconstruction was performed. Sixty-seven of the 72 patients who underwent a PLC reconstruction were assessed for anteroposterior laxity, with a mean side-to-side difference of 1.5 ± 1.1 mm. Evaluated by the objective International Knee Documentation Committee (IKDC) Knee Form, 88% of the patients who underwent a PLC reconstruction were graded as good/excellent (A/B). The 9 patients who underwent an early surgical repair of the PLC lesion were evaluated by means of the objective IKDC score, with 3 patients (33%) graded as good/excellent (A/B), and by means of a clinical evaluation, with 5 of 9 patients (56%) graded as 1+ for varus laxity. For the 14 patients who were managed nonoperatively for PLC injuries, the only clinical score available was the subjective IKDC score, with a mean value of 80.5 (87.8 for the 6 patients with type A PLC injuries and 75.0 for type B PLC injuries).

CONCLUSION

There is a paucity of literature focused on the management of combined ACL and PLC injuries. Combined ACL and PLC reconstruction seems to be the most effective approach to these combined lesions. However, future work is needed to explore the long-term outcome of the different treatment options.

Health-related quality of life after anterior cruciate ligament reconstruction: a systematic review

BACKGROUND

Anterior cruciate ligament reconstructions (ACLRs) are frequently performed on young, active patients and can result in persistent knee symptoms and activity limitations that may affect health-related quality of life (HRQoL). To date, there has been no systematic review of HRQoL outcomes after ACLR.

PURPOSE

The objectives of this study were to report HRQoL ≥5 years after ACLR, compare HRQoL outcomes with available population norms, and describe factors that may affect HRQoL in this population.

STUDY DESIGN

Systematic review.

METHODS

All studies reporting HRQoL ≥5 years after ACLR with hamstring or patellar tendon autografts were eligible for review. Common HRQoL outcomes were pooled using a random-effects meta-analysis and compared with published population norms. The Spearman rank correlation coefficient (ρ) was used to identify variables associated with HRQoL outcomes. Where insufficient data were available, outcomes were reported descriptively.

RESULTS

Fourteen studies were eligible for review, and HRQoL was reported for 2493 patients at a mean of 9 years (range, 5-16 years) after ACLR. Pooling of knee-related quality of life outcomes (Knee injury and Osteoarthritis Outcome Score [KOOS]-QOL) found impairments after ACLR when compared with population norms. In comparison, studies using the Short Form-36 (SF-36) reported similar or better HRQoL compared with normative data. The KOOS-QOL subscores correlated strongly with KOOS-sport/recreation (ρ = .70, P = .04) and KOOS-pain (ρ = .85, P = .003) subscores. Severe radiographic osteoarthritis, meniscal injuries sustained after surgery, and revision ACLR were associated with poorer HRQoL outcomes at a minimum 5-year follow-up. The negative influence of concomitant meniscal surgery on HRQoL became apparent more than 10 years after ACLR.

CONCLUSION

This review found that patients assessed using a knee-specific measure (KOOS-QOL) were more likely to report poorer HRQoL values, compared with population norms, than those assessed using a generic HRQoL measure (SF-36). Revision surgeries, meniscal injuries, and severe radiographic osteoarthritis were associated with poorer HRQoL outcomes after ACLR. However, these relationships should be interpreted with caution, as they were only investigated in a small number of studies.

CLINICAL RELEVANCE

These results can be used by clinicians to educate patients about potential long-term outcomes after ACLR and to develop strategies for optimizing postoperative HRQoL.

Revision anterior cruciate ligament reconstruction using tibial or hamstring tendon allografts

PURPOSE

To report outcomes of revision anterior cruciate ligament (ACL) reconstruction using tibial or hamstring tendon allografts and to compare with another study using non-irradiated fresh-frozen bone-patellar tendon-bone allografts.

METHODS

Records of 12 men and 7 women aged 18 to 53 (mean, 33) years who underwent revision ACL reconstructions using tibial tendon (n=17) or hamstring tendon (n=2) allografts were retrospectively reviewed. At the time of primary ACL reconstruction, hamstring autografts (n=8) and bonepatellar tendon-bone allografts (n=11) were used. The mean time interval between surgeries was 93 (range, 11-225) months. The causes of failure were traumatic injury (n=7) and technical or biological reasons (n=12). The physical activity level was high in 2 patients, medium in 10, and low in 7. For clinical assessment, the Lysholm test, International Knee Documentation Committee (IKDC) scale, and visual analogue scale (VAS) for pain were used. Patient satisfaction was also assessed.

RESULTS

Four of the patients had laxity and were dissatisfied or very dissatisfied with the outcome; the failure rate was 21%. The mean IKDC score was 63% (range, 25-100%), and the mean Lysholm score was 74% (range, 30-100%). Comparing our patients with those in another study using bone-patellar-bone allografts, there was no significant difference in terms of the VAS for pain, IKDC score, and Lysholm score. Comparing our patients with and without chondral and/or meniscal lesions, there was significant difference in terms of the Lysholm score only (86±11 vs. 57±28, p=0.043). Comparing patients who had used hamstring tendon autografts at the primary ACL reconstruction with those who had used bonepatellar tendon-bone autografts, there was significant difference in terms of the VAS for pain only (4.4±3.1 vs. 1.6±1.0, p=0.020).

CONCLUSION

Revision ACL reconstruction using tibial or hamstring tendon allografts provided acceptable results, similar to those using the bone-patellar tendon-bone allografts.

Avoiding Complications and Technical Variability During Arthroscopically Assisted Transtibial ACL Reconstructions by Using a C-Arm With Image Intensifier

BACKGROUND

Surgical reconstruction of the anterior cruciate ligament (ACL) can be complicated by incorrect and variable tunnel placement, graft tunnel mismatch, cortical breaches, and inadequate fixation due to screw divergence. This is the first report describing the use of a C-arm with image intensifier employed for the sole purpose of eliminating those complications during transtibial ACL reconstruction.

PURPOSE

To determine if the use of a C-arm with image intensifier during arthroscopically assisted transtibial ACL reconstruction (IIAA-TACLR) eliminated common complications associated with bone-patellar tendon-bone ACL reconstruction, including screw divergence, cortical breaches, graft-tunnel mismatch, and improper positioning of the femoral and tibial tunnels.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 110 consecutive patients (112 reconstructed knees) underwent identical IIAA-TACLR using a bone-patellar tendon-bone autograft performed by a single surgeon. Intra- and postoperative radiographic images and operative reports were evaluated for each patient looking for evidence of cortical breeching and screw divergence. Precision of femoral tunnel placement was evaluated using a sector map modified from Bernard et al. Graft recession distance and tibial α angles were recorded.

RESULTS

There were no femoral or tibial cortical breaches noted intraoperatively or on postoperative images. There were no instances of loss of fixation screw major thread engagement. There were no instances of graft-tunnel mismatch. The positions of the femoral tunnels were accurate and precise, falling into the desired sector of our location map (sector 1). Tibial α angles and graft recession distances varied widely.

CONCLUSION

The use of the C-arm with image intensifier enabled accurate and precise tunnel placement and completely eliminated cortical breach, graft-tunnel mismatch, and screw divergence during IIAA-TACLR by allowing incremental adjustment of the tibial tunnel and knee flexion angle. Incremental adjustment was essential to accomplish this. Importantly, a C-arm with image intensifier can be used with any ACL reconstruction that incorporates tunnels in the technique, with the expectation of increase in accuracy and precision and the elimination of common complications.

CLINICAL RELEVANCE

The use of an image intensifier during transtibial ACL reconstruction will substantially reduce the common complications associated with the procedure and improve both accuracy and precision of tibial and femoral tunnel placement. Use of an image intensifier unit is generalizable to an individual surgeon's preferences for graft choices and drilling techniques and will be especially valuable when the intercondylar architecture is altered from injury, time, or prior surgery.

Risk factors of subsequent operations after primary anterior cruciate ligament reconstruction

BACKGROUND

The incidence of nonrevision reoperations after anterior cruciate ligament reconstruction (ACLR) is less commonly studied and quantified.

PURPOSE

To describe the incidence of short-term reoperations after primary ACLR for the 4 most common procedures and to evaluate the risk factors associated with these reoperations.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Patients who underwent ACLRs and were enrolled in an ACLR registry between February 2005 and September 2011 were evaluated. First reoperations after primary ACLR performed for the 4 most common procedures (meniscal procedures, cartilage procedures, hardware removal procedures, and arthrofibrosis procedures) were the primary end points of the study. Patient, surgical, surgeon, and hospital risk factors associated with reoperations were evaluated, and Cox regression models were employed. Hazard ratios (HRs) and 95% confidence intervals (CIs) are reported.

RESULTS

A total of 14,522 ACLRs were identified. The patients had a mean age of 29.4 ± 11.5 years and were mostly male (63.3%) and white (48.3%). The mean follow-up was 1.9 ± 1.5 years (range, 0-6.7 years), and the median time to reoperation was 301 days (interquartile range, 172-515 days). The reoperation rate per 100 person-years of follow-up was 1.1 for meniscal reoperations, 0.3 for cartilage reoperations, 0.4 for hardware removal reoperations, and 0.4 for arthrofibrosis reoperations. Meniscal repair at the index ACLR was a significant risk factor for subsequent meniscal procedures (HR, 4.19; 95% CI, 3.10-5.67). Sports medicine fellowship training of the surgeon (HR, 2.17; 95% CI, 1.01-4.62) and older patient age (≤17 vs ≥26 years) (HR, 0.32; 95% CI, 0.12-0.81) were significant risk factors for cartilage reoperations. Use of allografts (HR, 1.90; 95% CI, 1.10-3.30) and female sex (HR, 1.75; 95% CI, 1.16-2.64) were risk factors for hardware removal reoperations. Female sex (HR, 2.48; 95% CI, 1.66-3.71) and prior surgery (HR, 3.02; 95% CI, 1.39-6.53) were risk factors for subsequent surgery for arthrofibrosis.

CONCLUSION

Overall short-term reoperation rates after ACLR are relatively low. Risk factors for subsequent surgery vary depending on the type of surgery evaluated. Some of the risk factors observed for reoperations include previous meniscal repair, female sex, allografts, prior surgery, older patient age, and being operated on by a sports medicine fellowship-trained surgeon.

How to read post-operative radiographs and CT scans after single-bundle anterior cruciate ligament reconstruction

Reconstruction of the anterior cruciate ligament (ACL) is a well-established surgical procedure. However, post-operative imaging in the early phase is not routinely performed. The rationale for performing such imaging is to provide a baseline examination for future controls, to provide immediate feedback to surgeons regarding tunnel placement, and to assess placement of fixation devices. The purpose of this paper is to enable the reader to accurately read post-operative radiographs and CT scans after single-bundle ACL reconstruction.

Coronal limb alignment and indications for high tibial osteotomy in patients undergoing revision ACL reconstruction

BACKGROUND

Failed ACL reconstruction frequently is accompanied by irreparable medial meniscal tear and/or visible osteoarthritis (OA) in the medial tibiofemoral joint. Thus, assessment for the presence of varus malalignment is important in caring for patients in whom revision ACL reconstruction is considered.

QUESTIONS/PURPOSES

We determined whether patients undergoing revision ACL reconstruction (1) have more frequent varus malalignment coupled with more severe degrees of medial meniscal injury and/or medial tibiofemoral OA, and (2) would meet potential indications for high tibial osteotomy more frequently than patients undergoing primary ACL reconstruction.

METHODS

We compared 58 patients undergoing revision ACL reconstruction and 116 patients undergoing primary ACL reconstruction. The mechanical tibiofemoral angle and the weight loading line (%) of the knee were measured. Additionally, radiographic degrees of OA in the tibiofemoral joints, and meniscal conditions were assessed. Then, proportions of potential candidates for high tibial osteotomy between the two groups were compared based on the following indications: (1) weight loading line less than 5%, (2) weight loading line less than 25% and medial tibiofemoral OA Kellgren-Lawrence Grade 3 or greater, or (3) weight loading line less than 25% and Kellgren-Lawrence Grade 2 medial tibiofemoral OA plus subtotal or total medial meniscectomy status.

RESULTS

The revision ACL reconstruction group had more frequent varus malalignment in terms of proportion of knees with more varus mechanical tibiofemoral angle than varus 5° (19% versus 8%, p = 0.029) and knees with weight loading line less than 25% (22% versus 9%, p = 0.011). This group also had more frequent high-grade injury of the medial meniscus (34% versus 16%, p = 0.007) and tended to have more frequent higher-grade radiographic OA at the medial tibiofemoral joint (19% versus 9%, p = 0.076). The percentage of patients meeting potential indications for high tibial osteotomy was greater in this group (14% versus 2%, p = 0.003).

CONCLUSIONS

We found that many patients undergoing revision ACL surgery may be reasonable candidates for concurrent high tibial osteotomy to address concomitant alignment and OA issues in the medial compartment. However, whether that additional intervention is offset by added risk and morbidity should be the focus of a future study, as it cannot be answered by a study of this design.

Passive anterior tibial subluxation in anterior cruciate ligament-deficient knees

BACKGROUND

Abnormal anterior-posterior and rotational motion secondary to anterior cruciate ligament (ACL) insufficiency is typically described in terms of dynamic laxity. An original description of the abnormal tibiofemoral relationship in the setting of ACL insufficiency has highlighted the presence of a fixed anterior tibial subluxation in this population of failed ACL reconstruction (ACLR); however, no study has quantified the degree of tibial subluxation in both the medial and lateral compartments.

PURPOSE

To measure and compare the amount of anterior tibial subluxation among various states of ACL competency, including (1) intact ACL, (2) acute ACL disruption, and (3) failed ACLR (ie, patients requiring revision ACLR). We hypothesized that anterior tibial displacement would be greater in the lateral compartment and in cases of failed ACLR compared with intact and acute ACL injured states.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

Using sagittal magnetic resonance imaging (MRI) and a standardized measurement technique, we determined the amount of anterior tibial subluxation relative to a constant posterior condylar reference point. Measurements were performed in both the medial and the lateral compartments and were compared with 1-way analysis of variance. The presence of meniscal tears along with meniscal volume loss and chondral damage was correlated with the amount of subluxation in each group.

RESULTS

Compared with the intact ACL state, the medial tibial plateau was positioned more anteriorly relative to the femur in both acute ACL injured knees (mean 1.0 mm) and those that failed ACLR (mean 1.8 mm) (P = .072). In the lateral compartment, there was 0.8 mm of mean anterior tibial displacement after acute ACL injury and 3.9 mm of mean anterior subluxation in patients who failed ACLR (P < .001). Mean anterior displacement of the lateral plateau in patients who failed ACLR was almost 5 times greater than the amount observed in patients with acute ACL injuries. There was no correlation between meniscal/chondral injury and the amount of subluxation.

CONCLUSION

Patients who require revision ACLR have an abnormal tibiofemoral relationship noted on MRI that is most pronounced in the lateral compartment and should be taken into account during revision surgery. These observations may explain the suboptimal clinical results seen in some patients who undergo revision ACLR.

Strategies for revision surgery after primary double-bundle anterior cruciate ligament (ACL) reconstruction

PURPOSE

The purpose of this article was to discuss pre- and intra-operative considerations as well as surgical strategies for different femoral and tibial tunnel scenarios in revision surgery following primary double-bundle anterior cruciate ligament (ACL) reconstruction.

METHODS

Based on the current literature of ACL revision surgery and surgical experience, an algorithm for revision surgery after primary double-bundle ACL reconstruction was created.

RESULTS

A guideline and flowchart were created using a case-based approached for revision surgery after primary double-bundle ACL reconstruction.

CONCLUSION

Revision surgery after primary double-bundle ACL reconstruction can be a challenging procedure that requires flexibility and a repertoire of surgical techniques. The combination of pre-operative planning with 3D-CT reconstruction, in addition to careful intra-operative assessment, and the use of this flowchart can simplify the ACL revision procedure.

LEVEL OF EVIDENCE

V.

Inferior results after revision ACL reconstructions: a comparison with primary ACL reconstructions

PURPOSE

Anterior cruciate ligament (ACL) ruptures are common, especially among young athletes, and such injuries may have considerable impact on both sport careers and everyday life. ACL reconstructions are successful for most patients, but some suffer from persistent giving-way symptoms and/or re-ruptures requiring revision surgery. The aim of this study was to evaluate the results after revision ACL reconstructions and compare them with the results in a control group consisting of primary ACL reconstructions.

METHODS

This retrospective study included 56 patients undergoing revision ACL reconstruction and 52 patients receiving primary ACL reconstructions. The follow-up evaluation included clinical examination, instrumented laxity testing, testing of muscle strength, Tegner activity score, Lysholm score, Knee injury and osteoarthritis outcome score (KOOS) and radiological grading of osteoarthritis.

RESULTS

The median time from the last ACL reconstruction to follow-up was 90 months in the revision ACL reconstruction group and 96 months in the primary ACL reconstruction group. The revision group had significantly inferior KOOS and Lysholm scores compared with the primary group. Patients in the revision group also showed greater laxity measured with the pivot shift test, a larger reduction in the Tegner activity score, reduced muscle strength in the injured knee, and more severe radiological osteoarthritis; however, no difference in anterior-posterior translation was found.

CONCLUSION

Inferior results were found on several of the testing parameters in the revision group compared with the primary group. Patients should receive this information prior to revision ACL reconstructions.

LEVEL OF EVIDENCE

III.

Radiographic findings in revision anterior cruciate ligament reconstructions from the Mars cohort

The Multicenter ACL (anterior cruciate ligament) Revision Study (MARS) group was developed to investigate revision ACL reconstruction outcomes. An important part of this is obtaining and reviewing radiographic studies. The goal for this radiographic analysis is to establish radiographic findings for a large revision ACL cohort to allow comparison with future studies. The study was designed as a cohort study. Various established radiographic parameters were measured by three readers. These included sagittal and coronal femoral and tibial tunnel position, joint space narrowing, and leg alignment. Inter- and intraobserver comparisons were performed. Femoral sagittal position demonstrated 42% were more than 40% anterior to the posterior cortex. On the sagittal tibia tunnel position, 49% demonstrated some impingement on full-extension lateral radiographs. Limb alignment averaged 43% medial to the medial edge of the tibial plateau. On the Rosenberg view (45-degree flexion view), the minimum joint space in the medial compartment averaged 106% of the opposite knee, but it ranged down to a minimum of 4.6%. Lateral compartment narrowing at its minimum on the Rosenberg view averaged 91.2% of the opposite knee, but it ranged down to a minimum of 0.0%. On the coronal view, verticality as measured by the angle from the center of the tibial tunnel aperture to the center of the femoral tunnel aperture measured 15.8 degree ± 6.9% from vertical. This study represents the radiographic findings in the largest revision ACL reconstruction series ever assembled. Findings were generally consistent with those previously demonstrated in the literature.

Outcomes of repeat revision anterior cruciate ligament reconstruction

BACKGROUND

As anterior cruciate ligament (ACL) reconstruction is performed increasingly in the United States, the rate of revision ACL reconstruction continues to rise. A paucity of literature exists with respect to repeat ACL revision surgery.

PURPOSE

To evaluate the functional outcomes of patients who had undergone at least 2 revision ACL reconstructions.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

The records of all patients who had undergone repeat revision ACL reconstructions between 1998 and 2009 were retrospectively reviewed. Data collected included patient demographics, operative findings, pre- and postoperative physical examination findings, radiographs, and Tegner, Lysholm, and International Knee Documentation Committee (IKDC) subjective scores.

RESULTS

Fifteen patients had undergone repeat revision ACL reconstruction during the study period. Mean age was 27 years (range, 18-57 years). Mean follow-up was 5 years (range, 2-10 years). At the time of repeat revision surgery, new tunnels were drilled in 9 of 15 (60%) cases. Of those, 8 of 9 (89%) were drilled because femoral tunnels were deemed "too anterior." During repeat revision, 11 of 15 (73%) patients were noted to have a meniscal tear, and 9 of 15 (67%) had International Cartilage Repair Society (ICRS) grade 3 or 4 chondral lesions. Mean Lysholm score was 60 preoperatively and increased to 82 postoperatively (P < .001). Mean preoperative IKDC score was 59, which increased to 80 postoperatively (P < .001). Mean preoperative Tegner score was 6.0. Mean postoperative Tegner score was 4.5, with only 4 of 15 (27%) patients having returned to their prior activity level (P < .001). Two patients (13%) sustained a traumatic rerupture. Presence of grade 3 or 4 chondral lesions and body mass index greater than 28 at the time of repeat revision were associated with a "fair" or "poor" outcome by Lysholm score (P = .007 and P = .03, respectively) and IDKC subjective scoring (P = .04 and P = .007, respectively).

CONCLUSION

Repeat revision ACL reconstruction may improve the functional outcomes of patients who have failed revision ACL reconstruction. Most patients do not return to prior activity level following repeat revision. Presence of grade 3 or 4 chondral lesions and body mass index greater than 28 were associated with worse outcomes.

Evaluation of information available on the Internet regarding anterior cruciate ligament reconstruction

Searching the Internet is one of the most popular methods for acquiring information related to health. The Internet offers physicians and patients easy access to a wide range of medical material from anywhere in the world. For many patients, this information helps formulate decisions related to their health and health care. An important caveat is that virtually anything can be published on the Internet. Although academic publications require rigorous peer review, Internet websites have no regulatory body monitoring quality and content. With a lack of external regulation, the information retrieved may be incorrect or outdated. The Internet can be a valuable asset for educating patients, but because of significant variability physicians should be familiar with the quality of information available. This article discusses both the strengths and weaknesses of information available on the Internet regarding anterior cruciate ligament repair.

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.

The effect of tunnel placement on rotational stability after ACL reconstruction: evaluation with use of triaxial accelerometry in a porcine model

PURPOSE

Conventional transtibial technique fails to restore the rotational knee stability in spite of successful anterior laxity, while anatomic anterior cruciate ligament reconstruction using the anteromedial portal technique has been developed expecting better rotational kinematics because of closer reproduction of the native anterior cruciate ligament anatomy. However, the rotational instability after those two procedures has not been fully examined especially in terms of dynamic component of the rotational stability. The purpose was to assess the effect of anatomic versus non-anatomic tunnel placement on rotational knee stability after anterior cruciate ligament reconstruction using triaxial accelerometry.

METHODS

Sixteen porcine knees underwent a manual pivot-shift test at four different conditions: (1) anterior cruciate ligament intact, (2) anterior cruciate ligament deficient, (3) non-anatomic transtibial reconstruction, and (4) anatomic anteromedial portal reconstruction. The three-dimensional acceleration of knee motion during the pivot-shift test was recorded using a triaxial accelerometer.

RESULTS

Both anterior cruciate ligament reconstructions decreased significantly the acceleration of the pivot-shift test from the increased level in the anterior cruciate ligament-deficient condition. However, the transtibial technique fails to reach the intact level of acceleration, while the anteromedial portal technique reduced the acceleration to even less than the intact level.

CONCLUSION

The transtibial anterior cruciate ligament reconstruction could not restore the dynamic rotational stability of the intact knee, whereas the anteromedial portal technique restored the dynamic rotational stability closer to the intact level.

LEVEL OF EVIDENCE

III.

Revision ACL reconstruction using contralateral hamstrings

PURPOSE

Due to the increasing number of primary anterior cruciate ligament (ACL) reconstructions, the need for revision surgery has risen. The aim of this study was to evaluate the use of contralateral doubled semitendinosus and gracilis tendon (DGST) for revision anterior cruciate ligament reconstruction.

METHODS

Twelve patients undergoing revision ACL reconstruction with hamstring tendon were examined at an average follow-up of 3 years. All patients underwent a thorough subjective and objective evaluation, which included a KT-1000 arthrometric evaluation, and a radiographic examination.

RESULTS

Subjective evaluation yielded a median score of 5.5 (range 2-9) on the Tegner activity scale. The mean Lysholm score was 95 (SD 9.5), and the mean subjective IKDC 2000 score was 95.4 (SD 7.8). At physical examination, a negative Lachman test was found in ten patients; one patient had a positive Lachman test with a firm end-point, and one other patient had a clearly positive Lachman test. Two patients had a grade 1+ on pivot shift testing. Only 1 patient showed a side-to-side difference more than 5 mm at the maximum manual KT-1000 arthrometer. Three patients (25 %) showed initial signs of osteoarthritis.

CONCLUSIONS

The results of the study show that the use of hamstring tendons harvested from the unaffected knee represents a valid option for revision surgery following a failed primary ACL reconstruction using DGST grafts.

LEVEL OF EVIDENCE

IV.

Allograft salvage procedure in multiple-revision anterior cruciate ligament reconstruction

BACKGROUND

Multiple-revision anterior cruciate ligament (ACL) reconstructions represent a surgical challenge due to the presence of previous tunnels, hardware, injuries to the secondary stabilizers, and difficulties in retrieving autologous tendons. An anatomic ACL reconstruction may therefore result in a demanding surgery, thus requiring 2 stages.

PURPOSE

To analyze the efficacy of an over-the-top ACL reconstruction technique plus extra-articular plasty using Achilles or tibialis posterior tendon allograft in restoring knee stability in patients with at least 2 failed previous ACL reconstructions, as well as to evaluate the factors able to affect the final outcome.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

From 2002 to 2008, 24 male athletes with a mean age of 30.8 years underwent surgery. Twenty patients had undergone 2, whereas 4 patients had undergone 3 previous reconstructions. The International Knee Documentation Committee (IKDC) score and KT-2000 arthrometric evaluation were used to measure outcomes at a mean follow-up period of 3.3 years (range, 2-7).

RESULTS

The mean ± SD IKDC subjective score at follow-up was 81.3 ± 14.0. The IKDC objective score was an A or B in 20 patients (83%). Arthrometer side-to-side difference averaged 3.1 ± 1.1 mm. Range of motion was normal or nearly normal in 23 patients and abnormal in 1. Of the 20 good results, 17 patients resumed sports activity at the preinjury level.

CONCLUSION

A 2-stage revision is an accepted option in cases of excessive tunnel enlargement and bone loss, especially on the femoral side, to achieve anatomic reconstruction. Nonanatomic over-the-top ACL reconstruction and lateral extra-articular plasty technique allow one to overcome difficult anatomic situations on the femoral side, permitting a 1-step surgery. The overall results obtained in this series are comparable with those of other ACL revision series. The higher rate of mild instability observed in our series may not be attributable to the surgical technique but rather to the chronic instability suffered by these knees before last revision.

Medial portal technique for single-bundle anatomical anterior cruciate ligament (ACL) reconstruction

The aim of the paper is to describe the medial portal technique for anatomical single-bundle anterior cruciate ligament (ACL) reconstruction. Placement of an ACL graft within the anatomical femoral and tibial attachment sites is critical to the success and clinical outcome of ACL reconstruction. Non-anatomical ACL graft placement is the most common technical error leading to recurrent instability following ACL reconstruction. ACL reconstruction has commonly been performed using a transtibial tunnel technique in which the ACL femoral tunnel is drilled through a tibial tunnel positioned in the posterior half of the native ACL tibial attachment site. ACL reconstruction performed using a transtibial tunnel technique often results in a vertical ACL graft, which may fail to control the combined motions of anterior tibial translation and internal tibial rotation which occur during the pivot-shift phenomenon. The inability of a vertically oriented ACL graft to control these combined motions may result in the patient experiencing continued symptoms of instability due to the pivot-shift phenomenon. The medial portal technique in which the ACL femoral tunnel is drilled through an anteromedial or accessory anteromedial portal allows consistent anatomical ACL tunnel placement. This paper describes the advantages of the medial portal technique, indications for the technique, patient positioning, proper portal placement, anatomical femoral and tibial tunnel placement, graft tensioning and fixation.

Preventing ACL injuries in team-sport athletes: a systematic review of training interventions

The purpose of this systematic review was to assess the efficacy of training interventions aimed to prevent and to reduce anterior cruciate ligament injury (ACLI) rates in team sport players. We searched MEDLINE from January 1991 to July 2011 using the terms knee, ACL, anterior cruciate ligament, injury, prevention, training, exercise, and intervention. Nine out of 708 articles met the inclusion criteria and were independently rated by two reviewers using the McMaster Occupational Therapy Evidence-Based Practice Research Group scale. Consensus scores ranged from 3 to 8 out of 10. Seven out of nine studies demonstrated that training interventions have a preventive effect on ACLI. Collectively, the studies indicate there is moderate evidence to support the use of multifaceted training interventions, which consisted of stretching, proprioception, strength, plyometric and agility drills with additional verbal and/or visual feedback on proper landing technique to decrease the rate of ACLIs in team sport female athletes, while the paucity of data preclude any conclusions for male athletes.

Arthroscopic agreement among surgeons on anterior cruciate ligament tunnel placement

BACKGROUND

Little is known about surgeon agreement and accuracy using arthroscopic evaluation of anterior cruciate ligament (ACL) tunnel positioning.

PURPOSE

To investigate agreement on ACL tunnel position evaluated arthroscopically between operating surgeons and reviewing surgeons. We hypothesized that operating and evaluating surgeons would characterize tunnel positions significantly differently.

STUDY DESIGN

Controlled laboratory study.

METHODS

Twelve surgeons drilled ACL tunnels on 72 cadaveric knees using transtibial (TT), medial portal (MP), or 2-incision (TI) techniques and then completed a detailed assessment form on tunnel positioning. Then, 3 independent blinded surgeon reviewers each arthroscopically evaluated tunnel position and completed the assessment form. Statistical comparisons of tunnel position evaluation between operating and reviewing surgeons were completed. Three-dimensional (3D) computed tomography (CT) scans were performed and compared with arthroscopic assessments. Arthroscopic assessments were compared with CT tunnel location criteria.

RESULTS

Operating surgeons were significantly more likely to evaluate femoral tunnel position (92.6% vs 69.2%; P = .0054) and femoral back wall thickness as "ideal" compared with reviewing surgeons. Tunnels were judged ideal by reviewing surgeons more often when the TI technique was used compared with the MP and TT techniques. Operating surgeons were more likely to evaluate tibial tunnel position as ideal (95.5% vs 57.1%; P < .0001) and "acceptable" compared with reviewers. The ACL tunnels drilled using the TT technique were least likely to be judged as ideal on the tibia and the femur. Agreement among surgeons and observers was poor for all parameters (κ = -0.0053 to 0.2457). By 3D CT criteria, 88% of femoral tunnels and 78% of tibial tunnels were placed within applied criteria.

CONCLUSION

Operating surgeons are more likely to judge their tunnels favorably than observers. However, independent surgeon reviewers appear to be more critical than results of 3D CT imaging measures. When subjectively evaluated arthroscopically, the TT technique yields more subjectively poorly positioned tunnels than the TI and MP techniques. Surgeons do not agree on the ideal placement for single-bundle ACL tunnels.

CLINICAL RELEVANCE

This study demonstrates that surgeons do not currently uniformly agree on ideal single-bundle tunnel placement and that the TT technique may yield more poorly placed tunnels.

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.

Two-stage revision anterior cruciate ligament reconstruction: indications, review, and technique demonstration

Revision anterior cruciate ligament reconstruction has inherent technical challenges not encountered during primary reconstruction. Prior tunnel placement and tunnel lysis can significantly alter graft fixation, compromising patient outcome. Preoperative recognition of patients with existing tunnel overlap and severe tunnel lysis will allow appropriate surgical planning and patient counseling, optimizing patient outcome. When single-stage revision is not possible in the presence of significant tunnel overlap and lysis, performing a 2-stage revision is recommended.

Failure of anterior cruciate ligament reconstruction

Failure after anterior cruciate ligament reconstruction is a potentially devastating event that affects a predominantly young and active population. This review article provides a comprehensive analysis of the potential causes of failure, including graft failure, loss of motion, extensor mechanism dysfunction, osteoarthritis, and infection. The etiology of graft failure is discussed in detail with a particular emphasis on failure after anatomic anterior cruciate ligament reconstruction.

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.

The accuracy of bone tunnel position using fluoroscopic-based navigation system in anterior cruciate ligament reconstruction

PURPOSE

The first purpose of this study was to examine whether fluoroscopic-based navigation system contributes to the accuracy and reproducibility of the bone tunnel placements in single-bundle anterior cruciate ligament (ACL) reconstruction. The second purpose was to investigate the application of the navigation system for double-bundle ACL reconstruction.

METHODS

A hospital-based case-control study was conducted, including a consecutive series of 55 patients. In 37 patients who received single-bundle ACL reconstruction, surgeries were performed with this system for 19 knees (group 1) and without this system for 18 knees (group 2). The positioning of the femoral and tibial tunnels was evaluated by plain sagittal radiographs. In 18 patients who received double-bundle ACL reconstruction using the navigation system (group 3), the bone tunnel positions were assessed by three-dimensional computed tomography (3D-CT). Clinical assessment of all patients was followed with the use of Lysholm Knees Score and IKDC.

RESULTS

Taking 0% as the anterior and 100% as the posterior extent, the femoral tunnels were 74.9 ± 3.0% in group 1 and 71.5 ± 5.8% in group 2 along Blumensaat's line, and the tibial tunnels were 42.3 ± 1.4% in group 1 and 42.5 ± 4.6% in group 2 along the tibia plateau. The bone tunnel positions in group 1 were located significantly closer to the position planned preoperatively and varied less in both femur and tibial side, compared with those without navigation (group 2). (Femur: P < 0.05, Tibia: P < 0.001) 3D-CT evaluation of double-bundle ACL reconstruction (group 3) also demonstrated that the bone tunnel positions of both anteromedial (AM) and posterolateral (PL) were placed as we expected.

CONCLUSION

The fluoroscopic-based navigation system contributed to the more reproducible placement of the bone tunnel during single-bundle ACL reconstruction compared with conventional technique. Additionally, this device was also useful for double-bundle ACL reconstruction.

LEVEL OF EVIDENCE

Case-control study, Therapeutic study, Level III.

Three-dimensional fluoroscopic navigation guidance for femoral tunnel creation in revision anterior cruciate ligament reconstruction

Revision anterior cruciate ligament (ACL) reconstruction is accompanied by several technical challenges that must be addressed, such as a primary malpositioned bone tunnel, pre-existing hardware, or bone defects due to tunnel expansion. We describe a surgical technique used to create an anatomic femoral socket using a 3-dimensional (3D) fluoroscopy-based navigation system in technically demanding revision cases. After a reference frame is rigidly attached to the femur, an intraoperative image of the distal femur is obtained, which is transferred to a navigation system and reconstructed into a 3D image. A navigation computer helps the surgeon to visualize the whole image of the lateral wall of the femoral notch, even if the natural morphology of the intercondylar notch has been destroyed by the primary procedure. In addition, the surgeon can also confirm the position of the previous bone tunnel aperture, the previous exit of the femoral tunnel, and the presence of any pre-existing hardware on the navigation monitor. When a new femoral guidewire for the revision procedure is placed, the virtual femoral tunnel is overlaid on the reconstructed 3D image in real time. At our institution, 12 patients underwent 1-stage revision ACL procedures with the assistance of this computer navigation system, and the grafts were securely fixed in anatomically created tunnels in all cases. This technology can assist surgeons in creating anatomic femoral tunnels in technically challenging revision ACL reconstructions.