Arthrometric Aspects of Anterior Cruciate Ligament Surgery Before and After Reconstruction With Patellar Tendon Grafts

Computer Patient-Specific 3D Modeling and Custom-Made Guides for Revision ACL Surgery

Revision anterior cruciate ligament reconstruction (ACLR) is a challenging surgery occurring in 3 to 24% of primary reconstructions. A meticulous planning to study the precise size and location of both femoral and tibial bone tunnels is mandatory. The aim of the study was to evaluate the intra- and interoperator differences in the decision-making process between experienced surgeons after they were asked to make preoperative planning for ACL revision reconstruction with the use of both the computed tomography (CT) scan and a three-dimensional (3D)-printed model of the knee. Data collected from 23 consecutive patients undergoing revision of ACLR for graft failure at a single institute between September 2018 and February 2020 were prospectively reviewed. The double-blinded collected data were presented to three board-certificate attending surgeons. Surgeons were asked to decide whether to perform one-stage or two-stage revision ACLR based on the evaluation of the CT scan images and the 3D-printed custom-made models at two different rounds, T0 and T1, respectively, 7 days apart one from the other. Interoperator consensus following technical mistake was 52% at T0 and 56% at T1 using the CT scans, meanwhile concordance was 95% at T0 and 94% at T1 using the 3D models. Concordance between surgeons following new knee injury was 66% at T0 and 70% at T1 using CT scans, while concordance was 96% both at T0 and T1 using 3D models. Intraoperative variability using 3D models was extremely low: concordance at T0 and T1 was 98%. McNemar test showed a statistical significance in the use of 3D model for preoperative planning (p < 0.005). 3D-printed model reliability resulted to be higher compared with CT as intraoperator surgery technique selection was not modified throughout time from T0 to T1 (p < 0.005). The use of 3D-printed models had the most impact when evaluating femoral and tibial tunnels, resulting to be a useful instrument during preoperative planning of revision ACLR between attending surgeons with medium-high workflow.

A non-weight bearing protocol after ACL reconstruction improves static anterior tibial translation in patients with elevated slope and increased weight bearing tibial anterior translation

PURPOSE

Aim of this study is to evaluate the impact of a non-weight bearing (NWB) protocol within 21 post-operative days after anterior cruciate ligament (ACL) reconstruction on static and dynamic anterior tibial translations (SATT and DATT, respectively). The hypothesis is that delayed WB would improve ATT at 9 months follow-up.

METHODS

A series of patients treated with ACL reconstruction was retrospectively reviewed, comparing a group with immediate post-operative weight bearing (WB group) and a group without post-operative weight bearing (NWB group). The NWB protocol was applied to patients with posterior tibial slope (PTS) ≥ 12°, pre-operative SATT ≥ 5 mm, and/or meniscal lesions of root or radial type. SATT, and PTS were measured on 20° flexion monopodal lateral x-rays, while DATT on Telos™ x-rays at pre-operative and 9-months follow-up.

RESULTS

One hundred seventy-nine patients were included (50 NWB group, 129 WB group). The SATT worsened in the WB group with a mean increase of 0.7 mm (SD 3.1 mm), while in the NWB group, the SATT improved with a mean decrease of 1.4 mm (SD 3.1 mm) from the pre-operative to 9 months' follow-up (p < 0.001). The side-to-side Telos™ evaluation showed a significant improvement in DATT within both the groups (p < 0.001), but there was no difference between the two groups (p = 0.99).

CONCLUSION

The post-operative protocol of 21 days without WB led to an improvement in SATT at 9 months without an influence on DATT, and it is recommended for patients with a SATT ≥ 5 mm and/or a PTS ≥ 12° as part of an "à la carte" approach to ACL reconstruction.

LEVEL OF EVIDENCE

Level IV, Retrospective case series.

Hamstring graft diameter above 7 mm has a lower risk of failure following anterior cruciate ligament reconstruction

PURPOSE

Multi-stranded hamstring-tendon autografts have been widely used for anterior cruciate ligament reconstruction (ACLR) surgeries. Recently, smaller diameter hamstring autografts have been linked with the risk of failure or graft rupture. However, there is limited evidence concerning the optimal diameter of the hamstring autografts for ACLR. The current systematic review and meta-analysis analysed the association of ACLR failure with the diameter of hamstring autografts.

METHODS

A systematic search of three major scientific databases (Pubmed, EMBASE, and Cochrane library) was conducted to identify studies that presented ACLR failure-related outcomes with different diameters of hamstring autografts. The pooled data from the included studies were analysed to investigate the association between ACLR failure and the cut-off diameters of 6, 7, 8, and 9 mm. Subgroup analyses based on the level of evidence and follow-up duration were also performed at each cut-off diameter.

RESULTS

Of the 2282 studies screened, 16 reported failure rates with hamstring autografts of different diameters, 15 of which were included in the meta-analysis. A graft diameter ≥ 7 mm was associated with significantly lower ACLR failure rates than a graft diameter < 7 mm (p = 0.005), based on pooled data of 19,799 cases. Age < 20 years and higher physical activity were associated with significantly higher ACLR failure rates.

CONCLUSION

The current systematic review suggests that the hamstring graft diameter for ACLR should be more than 7 mm considering the significantly higher failure rates with graft diameters less than 7 mm.

LEVEL OF EVIDENCE

Level IV.

The REVision Using Imaging to Guide Staging and Evaluation (REVISE) in ACL Reconstruction Classification

Revision anterior cruciate ligament (ACL) procedures are increasing in incidence and possess markedly inferior clinical outcomes (76% satisfaction) and return-to-sports (57%) rates than their primary counterparts. Given their complexity, a universal language is required to identify and communicate the technical challenges faced with revision procedures and guide treatment strategies. The proposed REV: ision using I: maging to guide S: taging and E: valuation (REVISE) ACL (anterior cruciate ligament) Classification can serve as a foundation for this universal language that is feasible and practical with acceptable inter-rater agreement. A focus group of sports medicine fellowship-trained orthopaedic surgeons was assembled to develop a classification to assess femoral/tibial tunnel "usability" (placement, widening, overlap) and guide the revision reconstruction strategy (one-stage vs. two-stage) post-failed ACL reconstruction. Twelve board-certified sports medicine orthopaedic surgeons independently applied the classification to the de-identified computed tomographic (CT) scan data of 10 patients, randomly selected, who failed ACL reconstruction. An interclass correlation coefficient (ICC) was calculated (with 95% confidence intervals) to assess agreement among reviewers concerning the three major classifications of the proposed system. Across surgeons, and on an individual patient basis, there was high internal validity and observed agreement on treatment strategy (one-stage vs. two-stage revision). Reliability testing of the classification using CT scan data demonstrated an ICC (95% confidence interval) of 0.92 (0.80-0.98) suggesting "substantial" agreement between the surgeons across all patients for all elements of the classification. The proposed REVISE ACL Classification, which employs CT scan analysis to both identify technical issues and guide revision ACL treatment strategy (one- or two-stage), constitutes a feasible and practical system with high internal validity, high observed agreement, and substantial inter-rater agreement. Adoption of this classification, both clinically and in research, will help provide a universal language for orthopaedic surgeons to discuss these complex clinical presentations and help standardize an approach to diagnosis and treatment to improve patient outcomes. The Level of Evidence for this study is 3.

Anterior Cruciate Ligament Graft Tunnel Placement and Graft Angle Are Primary Determinants of Internal Knee Mechanics After Reconstructive Surgery

BACKGROUND

Graft placement is a modifiable and often discussed surgical factor in anterior cruciate ligament (ACL) reconstruction (ACLR). However, the sensitivity of functional knee mechanics to variability in graft placement is not well understood.

PURPOSE

To (1) investigate the relationship of ACL graft tunnel location and graft angle with tibiofemoral kinematics in patients with ACLR, (2) compare experimentally measured relationships with those observed with a computational model to assess the predictive capabilities of the model, and (3) use the computational model to determine the effect of varying ACL graft tunnel placement on tibiofemoral joint mechanics during walking.

STUDY DESIGN

Controlled laboratory study.

METHODS

Eighteen participants who had undergone ACLR were tested. Bilateral ACL footprint location and graft angle were assessed using magnetic resonance imaging (MRI). Bilateral knee laxity was assessed at the completion of rehabilitation. Dynamic MRI was used to measure tibiofemoral kinematics and cartilage contact during active knee flexion-extension. Additionally, a total of 500 virtual ACLR models were created from a nominal computational knee model by varying ACL footprint locations, graft stiffness, and initial tension. Laxity tests, active knee extension, and walking were simulated with each virtual ACLR model. Linear regressions were performed between internal knee mechanics and ACL graft tunnel locations and angles for the patients with ACLR and the virtual ACLR models.

RESULTS

Static and dynamic MRI revealed that a more vertical graft in the sagittal plane was significantly related (P < .05) to a greater laxity compliance index (R² = 0.40) and greater anterior tibial translation and internal tibial rotation during active knee extension (R² = 0.22 and 0.23, respectively). Similarly, knee extension simulations with the virtual ACLR models revealed that a more vertical graft led to greater laxity compliance index, anterior translation, and internal rotation (R² = 0.56, 0.26, and 0.13). These effects extended to simulations of walking, with a more vertical ACL graft inducing greater anterior tibial translation, ACL loading, and posterior migration of contact on the tibial plateaus.

CONCLUSION

This study provides clinical evidence from patients who underwent ACLR and from complementary modeling that functional postoperative knee mechanics are sensitive to graft tunnel locations and graft angle. Of the factors studied, the sagittal angle of the ACL was particularly influential on knee mechanics.

CLINICAL RELEVANCE

Early-onset osteoarthritis from altered cartilage loading after ACLR is common. This study shows that postoperative cartilage loading is sensitive to graft angle. Therefore, variability in graft tunnel placement resulting in small deviations from the anatomic ACL angle might contribute to the elevated risk of osteoarthritis after ACLR.

Tibial fixation in anterior cruciate ligament reconstruction

OBJECTIVE

To determine whether supplementary tibial graft fixation with a staple is routinely necessary for anterior cruciate ligament (ACL) reconstructions.

METHODS

We retrospectively reviewed a series of consecutive patients who underwent ACL reconstruction at our institution from April 2012 to July 2013. Patients who fulfilled the inclusion and exclusion criteria were divided into two groups, of which one with tibial fixation of the graft with a biointerference screw alone (biointerference screw group) and the other with tibial fixation of the graft with a biointerference screw and supplementary extra tunnel staple fixation (biointerference screw and staple group). All the surgeries were performed by a single fellowship-trained sports surgeon, using a standardized transportal technique and rehabilitation protocol. Both well-matched groups were evaluated at 1-year follow-up objectively for ligament laxity using instrumented testing with KT-2000 arthrometer and clinical tests as well as subjectively with the validated International Knee Documentation Committee 2000 (IKDC) and Lysholm knee score. All complications were reported.

RESULTS

A total of 64 patients (31 in the only biointerference screw group and 33 in the biointerference screw and staple group) were included in the study. At 1 year, there was no significant difference in the objective and subjective outcome assessments between the two groups. However, four patients from the group with supplementary staple experienced symptomatic hardware on kneeling of which two necessitated removal of hardware.

CONCLUSION

Our study showed that supplementary tibial graft fixation with a staple is not routinely necessary for ACL reconstructions. It confers no additional benefits when compared with the use of biointerference screw alone for tibial graft fixation but may increase the risks of symptomatic hardware.

ACL Surgical Technique — Staying Out of Trouble

The incidence of ACL tear and reconstruction has increased over time, and failure of ACL reconstruction is not perfectly defined among surgeons. Atraumatic failure of ACL surgery represents approximately 70% of causes, and occurs in diagnostic errors, technical errors and problems of ACL graft integrations. Regarding surgical technique, we should answer certain questions about our choice of surgery, tunnel position, graft type, graft suture, tensioning the graft, and how we deal with certain incidents or intraoperative accidents. The purpose of this article is to review the current information and trends of ACL reconstruction, and presents some tips and tricks we use in our current practice.

Interval arthrometric comparison of anterior cruciate ligament reconstruction using bone-patellar tendon-bone autograft versus allograft: do grafts attenuate within the first year postoperatively?

BACKGROUND

There is little information regarding the incremental changes in the postoperative laxity of patellar tendon (PT) autografts versus allografts in anterior cruciate ligament (ACL) reconstruction.

HYPOTHESES

(1) There would be no significant increase in laxity between 6 weeks and 1 year postoperatively with PT autografts or allografts, (2) there would be no significant difference in laxity between PT autografts and allografts, (3) there would not be a significant difference in laxity between nonirradiated and low dose-irradiated PT allograft tissues, and (4) the physical examination findings would correlate with the instrumented laxity outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective review of 238 ACL-deficient patients who underwent single-incision endoscopic ACL reconstruction with a PT autograft (n = 132) or allograft (n = 106; 58 irradiated and 48 nonirradiated) from a single surgeon was made looking at data from preoperatively and from 6 weeks to 1 year postoperatively. The objective measurements of ligament integrity included range of motion, Lachman test, pivot-shift test, and KT-1000 arthrometer instrumented laxity examination. Failure was defined as arthrometric side-to-side differences (maximum manual difference) ≥3 mm or a positive pivot shift. Statistical significance was defined as P < .05.

RESULTS

There were no differences in postoperative examination findings or instrumented laxity between PT autografts and allografts (irradiated or nonirradiated) in either subgroup. The postoperative improvement based on the Lachman examination, pivot-shift test, and arthrometric data in all study groups was significant (P < .001) in 98% (autograft: n = 130; allograft: n = 104) of patients, and arthrometric failure correlated with failure by physical examination. There was no significant change in graft laxity, as measured by KT-1000 arthrometer, from 6 weeks to 1 year postoperatively for 98% of patients. Finally, there was no statistical correlation in instrumented laxity results for either the autograft or allograft group with reference to age, gender, concurrent meniscectomy, meniscal repairs, interval to surgery, postoperative patellar pain, time to surgery, or irradiated versus nonirradiated allograft.

CONCLUSION

Laxity is not increased after the initial 6 weeks for either PT allograft or autograft constructs during the first postoperative year. There was no correlation between age, gender, concomitant injury, interval to surgery, or radiation of the graft with instrumented laxity results. Furthermore, our arthrometric data paralleled our clinical findings of stability at follow-up.

A new diagnostic approach using regional analysis of anterior knee laxity in patients with anterior cruciate ligament deficiency

PURPOSE

The first purpose of this study was to analyze the characteristics of the anterior knee laxity in the three regions of different stiffness in the force-displacement curve, which was obtained from a frequently used arthrometer for quantifying knee joint stability in the patients with anterior cruciate ligament (ACL) rupture and the healthy controls. The second purpose was to compare the characteristics from the regional analysis of the anterior knee laxity between the two subject groups in order to explore proper diagnosis criteria.

METHODS

Seventy-one patients with unilateral ACL tear and eighty healthy controls were enrolled and their anterior knee laxities were tested using the KT-2000 arthrometer. The displacements and stiffness of the three regions were extracted separately and compared between groups to further develop the diagnostic criteria.

RESULTS

The results indicated that the laxity behavior was mostly affected in Region 2 and Region 3 after ACL tear. Two good indicators for ACL tear were found in the receiver operating characteristic (ROC) curve analysis: Region 2 with the displacement larger than 3.7 mm and Region 3 with the stiffness smaller than 22 N/mm. These two criteria provided a better diagnostic accuracy with increased sensitivity.

CONCLUSIONS

The regional analysis method developed in this study could provide more information for understanding the characteristics of the anterior knee laxity and help increase the diagnostic accuracy for ACL rupture.

LEVEL OF EVIDENCE

II.

Complications of anterior cruciate ligament reconstruction with bone-patellar tendon-bone constructs: care and prevention

Rupture of the anterior cruciate ligament is a common injury. Correct diagnosis and patient selection, along with proper surgical technique, with careful attention to anatomic graft placement, followed by attention to proper rehabilitation, leads to predictably good to excellent results. This article reviews the recognition and avoidance of complications associated with bone-patellar tendon-bone constructs of anterior cruciate ligament reconstruction.