Revascularization process of the bone--patellar tendon--bone autograft evaluated by contrast-enhanced magnetic resonance imaging 6 and 12 months after anterior cruciate ligament reconstruction

Comparison of "ligamentization" process between preserved insertion hamstring tendon autograft and bone-patellar tendon-bone autograft

BACKGROUND

Ligamentization is a complex process and effect of preservation of hamstring tendon graft insertion on this process is not well studied. Present study was conducted to analyze and compare the ligamentization of semitendinosus gracilis graft with preserved tibial insertion (STGPI) and bone-patellar tendon-bone (BPTB) autografts.

METHODS

A total of 50 sportspeople who underwent ACL reconstruction using either BPTB (group A; n = 25) or STGPI (group B; n = 25) autografts were included in the study. Contrast enhanced MRI was done at 8 months and 14 months post-ACL reconstruction to evaluate the ligamentization using Signal noise quotient (SNQ), graft intensity and enhancement index. Clinical outcomes (Lysholm score) and knee laxity were also assessed at 8 months and 14 months.

RESULTS

18/23 (78%) patients in group A and 14/23 (61%) patients in group B had hyperintense graft signal at 8 months (n.s.) and at 14 months, 1/23 patients in group A and none of the patients in group B had hyperintense graft. SNQ at 8 months was 3.6 ± 2 and 3.7 ± 2 in group A and B respectively (n.s.) and at 14 months, SNQ was 2.5 ± 1.5 in group A and 2.4 ± 1.3 in group B (n.s.). Enhancement index at 8 months was 1.5 ± 0.3 and 1.2 ± 0.3 in group A and B respectively (p = 0.0001). Enhancement index at 14 months was 1.21 ± 0.2 in group A and 1.07 ± 0.2 in group B (p = 0.003). Functional outcomes and knee laxity were comparable in both the groups at 8 and 14 months (n.s.).

CONCLUSION

Both the grafts i.e. BPTB and STGPI are similar in terms of rate and extent of ligamentization. Clinical outcomes and knee laxity are also comparable between two grafts.

Intra-femoral tunnel graft lengths less than 20 mm do not predispose to early graft failure, inferior outcomes or poor function. A prospective clinico-radiological comparative study

PURPOSE

Increasing demands on skills with mounting pressures from expectations from arthroscopic anterior cruciate ligament (ACL) reconstructions requires precise knowledge of technical details by surgeons. One such element is the minimum length of graft in femoral tunnel to allow for adequate tendon-to-bone healing and early return to activities and sports. This has, however, remained an unanswered question.

PURPOSE

To study and compare clinico-radiological outcomes of ACL reconstructions in patients with < 20 mm of intra-femoral tunnel graft length with those measuring ≥ 20 mm.

METHODS

All eligible patients undergoing arthroscopic ACL reconstruction were sequentially divided into two groups based on the intra-femoral tunnel graft lengths (A: < 20 mm, n = 27; and B: ≥ 20 mm, n = 25). Exclusions were made for those > 45 years of age, with chondral and/or multi-ligamentous injuries and with systemic pathologies. All patients were postoperatively evaluated in clinics by physical examination and functional scoring (Lysholm and modified Cincinnati scores) at 3, 6 and 12-month intervals. Graft vascularity was assessed by signal-to-noise quotient ratio (SNQR) using magnetic resonance imaging (MRI) at 3 and 12 months.

RESULTS

No significant differences were noted in mean Lysholm and modified Cincinnati scores between the two groups at the end of 1 year. There were also no significant differences in graft maturation over time and SNQR at 3 and 12 months in the region of interest (ROI).

CONCLUSIONS

Intra-femoral tunnel graft length of less than 20 mm does not compromise early clinical and functional outcomes of ACL reconstructions.

Synergistic Effect of Reverse Drilling and Bone Dust on Femoral Tendon-Bone Healing After Anterior Cruciate Ligament Reconstruction in a Rabbit Model

BACKGROUND

Anterior cruciate ligament (ACL) injuries and bone tunnel enlargement (BTE) after ACL reconstruction (ACLR) remain frequent issues. Bone dust (BD) produced by tunnel preparation with osteogenic ability and reverse drilling (RD), an easy compaction technique, make it accessible to enhance tendon-bone healing in the clinic.

HYPOTHESIS

RD and BD synergistically promote tendon-bone healing by improving peritunnel bone and preventing BTE in femurs.

STUDY DESIGN

Controlled laboratory study.

METHODS

In total, 96 New Zealand White rabbits underwent ACLR. The semitendinosus tendon was freed before medial parapatellar arthrotomy. After the native ACL was transected, bone tunnels were prepared through the footprint of the native ACL. All animals were randomly assigned to 1 of 4 groups according to different tunnel preparation methods: group 1 (irrigation after extraction drilling [ED]; control group), group 2 (irrigation after RD), group 3 (no irrigation after ED), and group 4 (no irrigation after RD). BD was harvested by irrigating tunnels and was characterized by morphology and size. The specimens underwent microarchitectural, histological, and biomechanical evaluations at 4, 8, and 12 weeks postoperatively.

RESULTS

Micro-computed tomography demonstrated more peritunnel bone and less BTE in the femurs of group 4 compared with the other groups. Histologically, BD possessed osteogenic activity in bone tunnels postoperatively. Meanwhile, group 4 regenerated a higher amount of the tendon-bone interface and more peritunnel bone than group 1. Biomechanically, group 4 showed higher failure loads and stiffness than group 1. However, peritunnel bone loss, active osteoclasts, and significant BTE were found in the femurs of group 1 and group 3 at 12 weeks postoperatively, while no strong correlation was found between BTE and inflammatory cytokines. Scanning electron microscopy and particle size analysis suggested that BD produced by ED and RD had no difference in size.

CONCLUSION

Tendon-bone healing was facilitated by the synergistic effect of RD and BD in femurs.

CLINICAL RELEVANCE

This study provides a more accessible and effective surgical strategy to promote tendon-bone healing after ACLR by increasing peritunnel bone and preventing BTE in femurs.

Revascularization character of autologous fascia lata graft following shoulder superior capsule reconstruction by enhanced magnetic resonance imaging

Background

Fascia lata has been used for arthroscopic superior capsule reconstruction (ASCR) and verified to achieve a good clinical outcome. However, it is still not known about revascularization character of the fascia lata after ASCR. This study was performed to evaluate the revascularization of autologous fascia lata grafts after ASCR by enhanced magnetic resonance imaging (MRI).

Methods

A prospective study of 19 patients with irreparable rotator cuff tears underwent ASCR with autologous fascia lata grafts from September 2019 to April 2021. Radiography examinations and clinical evaluations were performed preoperatively and postoperatively at 6 weeks and 3, 6, and 12 months. The signal-to-noise quotient (SNQ) value and enhancement index (EI) of autologous fascia lata grafts in the great tubercle insertion (GTI), midpoint of the graft (MG), and glenoid insertion (GI) were compared for radiography examination. Clinical evaluation included the American Shoulder and Elbow Surgeons (ASES) score, University of California Los Angeles (UCLA) shoulder score, and Visual Analog Scale (VAS) score.

Results

The SNQ values in T1WI enhancement at GI and GTI were significantly higher than those at the plain MRI scan at all postoperative observation timepoints; however, the SNQ values in T1WI enhancement at MG did not show a significant difference until 3 months postoperation. EI values at GTI and GI were significantly higher than those at MG at 6 weeks and 3 months postoperation, while there was no significant difference in the EI value between GTI and GI. At 6 months postoperation, the EI value at GI was significantly higher than those at MG. At 12 months postoperation, the EI value at GI was significantly higher than those at MG and GTI; however, there was no significant difference between GTI and MG. The EI values at GTI and MG peaked at 3 months and 6 months postoperation, respectively, and then plateaued at 12 months postoperation. However, there was no significant difference in the EI value among the different postoperative timepoints at GI. The EI value did not correlate with the VAS and ASES, UCLA scores at any time point or any postoperative observation location.

Conclusion

Revascularization of the fascia lata was dependent on the location of the fascia lata and plateaus at 12 months postoperation. The EI value did not correlate with the VAS and ASES, UCLA scores during12 months postoperation.

Returning Athletes to Sports Following Anterior Cruciate Ligament Tears

PURPOSE OF REVIEW

The purpose of this review is to discuss treatment options, rehabilitation protocols, return-to-play criteria, and expected outcomes after non-operative and operative treatment of anterior cruciate ligament (ACL) tears among an athletic population.

RECENT FINDINGS

Non-operative treatment may be a viable option for some athletes with an ACL tears but can be difficult to predict "copers," and those that resume to sports return at lower performance level and/or less intense activities. Most studies assessing function after ACL reconstruction demonstrate favorable outcomes using patient-reported outcome studies. However, return-to-play and graft re-rupture rates vary substantially based on patient characteristics and level and type of athletic activity. Grafts used to reconstruct ACL produce similar objective outcomes and favorable patient-reported outcomes but have variable re-rupture rates depending on study and differ largely on morbidity associated with graft harvest. Various treatment methods including non-operative and operative techniques have been demonstrated to be efficacious in returning athletes to athletic activity depending on patient age and level of activity. Adherence to fundamental rehabilitation principles and accepted return-to-play guidelines can optimize outcomes and limit re-injury to the injured or contralateral limb.

Association Between Early Postoperative Graft Signal Intensity and Residual Knee Laxity After Anterior Cruciate Ligament Reconstruction

Background:

Magnetic resonance imaging (MRI) graft signal intensity is associated with graft damage after anterior cruciate ligament reconstruction (ACLR). However, little is known about the relationship between graft signal intensity and residual laxity of the reconstructed knee based on patient age.

Purpose/Hypothesis:

To evaluate the relationship between graft signal intensity and residual laxity in younger and older patients who underwent ACLR. We hypothesized that higher graft signal intensity would be associated with reduced postoperative knee stability.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

A total of 192 patients who underwent double-bundle ACLR were recruited. Proton density–weighted and T2-weighted MRI was performed at 3, 6, and 12 months after surgery, and the signal intensity ratio (SIR) of the anteromedial and posterolateral bundles was measured as the graft signal intensity reference values. At 12 months after surgery, if the KT-1000 arthrometer measurement exhibited a side-to-side difference of ≥2 mm, the patient was determined as having anterior knee laxity. Rotatory knee laxity was defined as a positive pivot shift with International Knee Documentation Committee grade ≥1. The Mann-Whitney U test was used to compare the SIR in patients with and without residual laxity. The Spearman correlation coefficient was used to evaluate the relationship between demographic parameters and the SIR. Based on receiver operating characteristic curves, the optimal SIR cutoff values to predict residual laxity were calculated, and logistic regression analysis was conducted.

Results:

Of 192 patients, 26 (13.5%) had anterior knee laxity, and 20 (10.4%) had rotatory knee laxity. The SIR was negatively correlated with age. In younger patients (<30 years; n = 135), those with residual laxity had a significantly higher SIR than those without laxity; this relationship was not significant in older patients (≥30 years; n = 57). Based on receiver operating characteristic curves and logistic regression analysis, the cutoff values that were determined for the SIR were significantly associated with a higher odds ratio of residual laxity.

Conclusion:

Graft signal intensity decreased with patient age. Patients with higher graft signal intensity in the early postoperative phase after ACLR exhibited a higher prevalence of residual laxity, particularly in younger patients.

Superb microvascular imaging (SMI) detects increased vascularity of the torn anterior cruciate ligament

PURPOSE

Ultrasound with superb microvascular imaging (SMI) is a novel microvascular imaging technology which may be useful to assess the vascularity of the torn anterior cruciate ligament (ACL) as a potential measure of healing potential following surgery. This study aimed to quantify the vascularity of the torn and intact ACL using ultrasound with SMI.

METHODS

23 patients (mean age ± standard deviation, 27.1 ± 12.8 years), who were diagnosed with an ACL tear with an intact contralateral ACL were enrolled (ACL injury group). Ten healthy volunteers (36.1 ± 4.9 years) who had intact ACLs in both knees were also recruited (ACL healthy controls). The vascularity of the ACL was assessed using SMI within 15 mm from the tibial insertion in both knees. The amount of the vascular signal was assessed using a semi-quantitative grading scale (vascularity grade: grade 0-3) and a quantified ratio of vascularized area with respect to total area of the region of interest (vascularity ratio).

RESULTS

In the ACL injury group, a significantly higher vascularity grade and ratio were observed in the torn ACL (vascularity grade 0-3: 1, 8, 7, and 7 patients, respectively; vascularity ratio: 1.3 ± 1.4%) than the contralateral intact ACL (vascularity grade 0-3: 21, 1, 1, and 0 patients, respectively; vascularity ratio: 0.1 ± 0.5%) (P < 0.001), whereas no significant difference was observed between both ACLs in the ACL healthy control group.

CONCLUSIONS

SMI was useful to assess the increased vascularity in torn ACL, which may reflect the potential for, or state of, ACL maturation following reconstruction or repair.

LEVEL OF EVIDENCE

Level III.

Chronological changes in cross-sectional area of the bone-patellar tendon-bone autograft after anatomic rectangular tunnel ACL reconstruction

PURPOSE

The purpose of this study was to evaluate the change in cross-sectional area (CSA) of bone-patellar tendon-bone (BTB) autografts up to 5 years after the anatomic rectangular tunnel (ART) anterior cruciate ligament reconstruction (ACLR). The changing pattern in CSA might be a potential indicator of the graft remodeling process.

METHODS

Ninety-six (62 males, 34 females, mean age 27.0 years) patients were enrolled in this study with a total of 220 MRI scans after ART BTB ACLR to evaluate the CSA of the ACL autografts. The patients with first time unilateral ACLR that consented to undergo MRI evaluations at postoperative periods were included in this study. Intraoperatively, the CSA of the graft was measured directly using a custom-made area micrometer at the midpoint of the graft. Postoperatively, using an oblique axial slice MRI that was perpendicular to the long axis of the graft, the CSA of the graft was measured with digital radiology viewing program "SYNAPSE" at the midpoint of the graft. The postoperative MRI scans were classified into seven groups according to the period from ACLR to MRI evaluation: Group 0-2 months (m.), Group 3-6 m., Group 7-12 m., Group 1-2 years (y.), Group 2-3 y., Group 3-4 y., and Group 4 y.-. The percent increase of the CSA was calculated by dividing the postoperative CSA by the intraoperative CSA.

RESULTS

The postoperative CSA was significantly larger than the intraoperative CSA in each group, with the exception of Group 0-2 m. The mean percent increase of the CSA in Group 0-2 m., 3-6 m., 7-12 m., 1-2 y., 2-3 y., 3-4 y., 4 y.- was 101.8 ± 18.2, 188.9 ± 27.4, 190.9 ± 43.7, 183.3 ± 28.9, 175.2 ± 27.9, 163.9 ± 19.8, 164.5 ± 25.4% respectively. The percent increase in Group 3-6 m., 7-12 m., 1-2 y., 2-3 y., 3-4 y., and 4 y.- was significantly greater than that in Group 0-2 m.

CONCLUSIONS

The CSA of the BTB autografts after the ART BTB ACLR increases rapidly by 3-6 months after ACLR, reached a maximum value of 190% at around 1 year, decreases gradually after that, and reaches a plateau at around 3 years. The current study might help clinicians to estimate an individual BTB autograft's remodeling stages when considering returning patients to sports.

LEVEL OF EVIDENCE

IV.

Effect of Time on MRI Appearance of Graft After ACL Reconstruction: A Comparison of Autologous Hamstring and Quadriceps Tendon Grafts

Background:

After anterior cruciate ligament (ACL) reconstruction (ACLR), changes in the appearance of the ACL graft can be monitored using magnetic resonance imaging (MRI).

Purpose:

The purpose of this study was to evaluate and compare the MRI signal intensity (SI) of hamstring and quadriceps tendon grafts during the first postoperative year after ACLR. As a secondary aim, the relationship of SI to clinical and anatomic measurements was analyzed.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 78 patients who underwent ACLR with an autologous graft were reviewed; 55 received hamstring grafts and 23 received quadriceps tendon grafts. At 3 and 9 months postoperatively, 3-T MRI was performed using a dedicated knee coil, and the median SI of the intra-articular ACL graft was measured on sagittal-plane images. Postoperative lateral radiographs were analyzed to determine medial and lateral posterior tibial slope (PTS). Side-to-side difference in anterior knee laxity between injured and uninjured limbs was measured at 6 and 12 months postoperatively.

Results:

The median SI of quadriceps grafts was significantly greater than hamstring grafts at 3 months after ACLR (P = .02). Between 3 and 9 months, the median SI of quadriceps grafts decreased (P < .001), while that of hamstring grafts did not significantly change (P = .55). The lateral PTS was significantly correlated with median SI measurements at 3 and 9 months such that greater lateral PTS values were associated with greater median SI. The side-to-side difference in anterior knee laxity decreased for the quadriceps group (P = .04) between 6 and 12 months but did not change for the hamstring group (P = .88).

Conclusion:

The median SI of quadriceps grafts significantly decreased on MRI between 3 and 9 months after ACLR, while the median SI of hamstring grafts did not significantly change. The change in MRI appearance of the quadriceps grafts was paralleled by a reduction in anterior knee laxity between 6 and 12 months after surgery. In the absence of standardized imaging techniques and imaging analysis methods, the role of MRI in determining graft maturation, and the implications for progression through rehabilitation to return to sport, remain uncertain.

Combination of anterior tibial and femoral tunnels makes the signal intensity of antero-medial graft higher in double-bundle anterior cruciate ligament reconstruction

PURPOSE

To elucidate whether sagittal graft tunnel affects the signal intensity in anatomical ACL reconstruction (ACLR) and to clarify the prevalence of intercondylar roof impingement. It was hypothesized that if the tunnel apertures are located within the anatomical footprint of ACL, tunnel position would not affect the signal intensity.

METHODS

A total of 132 patients who underwent anatomical double-bundle ACLR (DB-ACLR) using hamstring autograft were recruited. Tunnel position was determined by the quadrant method on three-dimensional computed tomography; the femoral tunnel position was defined as "high and low" or "deep and shallow", while that of the tibial side was defined as "anterior and posterior" or "medial and lateral". Subjects were divided into three groups according to the tertile of % deep-shallow. The signal intensity was evaluated by the region of interest value of the antero-medial bundle (AMB) and postero-lateral bundle on magnetic resonance imaging at 12 months after reconstruction. Linear regression analysis was conducted to elucidate the relationship between the percentage position of each tunnel and the graft signal intensity.

RESULTS

In the shallow tertile group, AMB signal intensity increased in the anterior position of the tibial tunnel (β = - 0.34; P = 0.025). In the intermediate and deep tertile groups, the tunnel position did not correlate with the signal intensity.

CONCLUSIONS

A more anterior tibial tunnel position increases AMB signal intensity in shallower femoral tunnel. Conversely, this correlation is attenuated for deeper femoral tunnels. Surgeons should pay attention to sagittal femoral tunnel position to create a more anterior tibial tunnel position.

LEVEL OF EVIDENCE

Level III.

Hamstring grafts for anterior cruciate ligament reconstruction show better magnetic resonance features when tibial insertion is preserved

PURPOSE

Comparing the MRI features of the grafts between a group of patients treated with an over-the-top anterior cruciate ligament reconstruction technique that preserves the hamstring attachment and a control group with a classical reconstruction technique.

METHODS

Patients were assigned to a standard reconstruction technique or an Over-the-top plus lateral plasty technique. All patients underwent preoperative, 4-months and 18-months MRI; together with a clinical evaluation with KOOS and KT1000 laxity assessment. MRI study involved different parameters: the "Graft" was evaluated with the continuity, Howell Grading system, presence of liquid and signal noise quotient. The "Tibial Tunnel" was evaluated with the signal noise quotient, presence of edema or liquid and tunnel widening. All points assigned to each parameter formed a composite score ranging from 0-10. Tunnel and graft positioning were evaluated.

RESULTS

At 18-month 20 MRIs (10 each group) were available, demographics were not significantly different between groups. The non-detached group showed significantly less liquid within the graft at 4-months (p = 0.008) and 18-months (p = 0.028), the tunnel was significantly smaller (p < 0.05) and less enlarged at both follow-ups (p < 0.05), signal noise quotient of the intra-tunnel graft was lower at 18-months (p < 0.05). The total score of the non-detached group saw a significant improvement at 4-months (p = 0.006) that remained stable at 18-months (n.s.).

CONCLUSIONS

Hamstring grafts, which tibial insertions were preserved, showed better MRI features at 4-and 18-months follow-up, especially in terms of liquid effusion, tunnel enlargement and signal noise quotient.

LEVEL OF EVIDENCE

IV.

Remnant-Tensioning Single-Bundle Anterior Cruciate Ligament Reconstruction Provides Comparable Stability to and Better Graft Vascularity Than Double-Bundle Anterior Cruciate Ligament Reconstruction in Acute or Subacute Injury: A Prospective Randomized Controlled Study Using Dynamic Contrast-Enhanced Magnetic Resonance Imaging

PURPOSE

To compare the clinical, second-look arthroscopic, magnetic resonance imaging (MRI), and dynamic-contrast-enhanced MRI (DCE-MRI) findings between remnant-tensioning single-bundle (RT-SB) and double-bundle (DB) anterior cruciate ligament reconstruction (ACLR).

METHODS

Sixty-seven patients with acute or subacute anterior cruciate ligament (ACL) injury were randomized to undergo RT-SB or DB ACLR. Twenty-six patients in the RT-SB group and 28 in the DB group were evaluated using stability tests (Lachman test, pivot-shift test, and KT-2000 arthrometer) and multiple clinical scores. One year postoperatively, all 54 patients underwent MRI for evaluation of graft continuity and graft signal/noise quotient and DCE-MRI for the calculation of normalized area under the curve (nAUC) as a marker of graft vascularity. Among them, 41 patients underwent second-look arthroscopy for the evaluation of graft continuity, graft tension, and synovialization. The results were compared between the 2 groups.

RESULTS

At the minimum 2-year follow-up (28.7 ± 6.4 months), the stability tests, clinical scores, second-look arthroscopic findings, and MRI findings were not significantly different between the groups. However, the mean nAUC values on DCE-MRI for the ACL graft were significantly higher in the RT-SB group than those in the DB group in all 3 zones (nAUC_proximal, P = .005; nAUC_middle, P = .021; nAUC_distal, P = .027; and nAUC_average, P = .008).

CONCLUSION

For acute or subacute ACL injury, the RT-SB ACLR showed an outcome comparable to that of DB ACLR in terms of knee stability, clinical scores, MRI findings, and second-look arthroscopic findings. Moreover, RT-SB ACLR showed better graft vascularity 1 year postoperatively than DB ACLR using DCE-MRI.

LEVEL OF EVIDENCE

II, prospective randomized controlled trial.

The relationship between graft synovialization and graft revascularization after ACL reconstruction: Assessment using dynamic contrast enhanced-MRI and second-look arthroscopy

PURPOSE

To assess graft vascularity via dynamic contrast enhanced-magnetic resonance imaging (DCE-MRI) at 1-year and 2-year postoperatively and to evaluate the relationship between the vascularity using DCE-MRI and the synovialization using second-look arthroscopy.

MATERIALS AND METHODS

Fifty-four patients from prospective data included who underwent anterior cruciate ligament reconstruction (ACLR) and DCE-MRI. The graft was divided into proximal, middle, and distal zones; average of three zones was calculated. Signal/noise quotient (SNQ) was measured on proton-density image and normalized area under the curve (nAUC) was calculated from DCE-MRI. The results at 1-year (SNQ-1 and nAUC-1) and 2-year (SNQ-2 and nAUC-2) postoperatively were compared between two time points. Forty-one patients underwent second-look arthroscopy were classified into three groups according to the synovialization: Excellent (n = 17), Fair (n = 16), and Poor (n = 8). The SNQs and nAUCs were compared between three groups.

RESULTS

Fifty-four and 23 patients underwent DCE-MRI at 1-year and 2-year, respectively. A significant decrease was observed from nAUC_average-1 to nAUC_average-2 (95 % confidential interval, 0.4-2.3; P = .007). Both SNQ_average-1 and SNQ_average-2 were significantly lower in the excellent than in the poor (SNQ_average-1, P < .001; SNQ_average-2, P = .003). Both SNQ_average-1 and SNQ_average-2 were significantly lower in the fair than in the poor (SNQ_average-1, P=.032; SNQ_average-2, P = .012). Both nAUC_average-1 and nAUC_average-2 were significantly higher in the excellent than in the poor (nAUC_average-1, P < .001; nAUC_average-2, P = .010). The nAUC_average-1 was significantly higher in the excellent than the fair (nAUC_average-1, P < .001).

CONCLUSION

Well-synovialized grafts showed significantly lower SNQs and significantly higher nAUCs than did poor-synovialized grafts based on the second-look arthroscopic findings. We can indirectly infer from this result that well-synovialized grafts may have better biomechanical properties.

Revascularization to the bone tunnel wall after anterior cruciate ligament reconstruction may relate to the distance from the vessels

Purpose

We use magnetic resonance angiography to evaluate the difference of vascular ingrowth to the bone tunnel on the anterior and posterior walls quantitatively after anterior cruciate ligament reconstruction.

Materials and methods

One hundred patients underwent anterior cruciate ligament reconstruction with multi-stranded semitendinosus tendons. They were retrospectively divided into those who underwent magnetic resonance angiography 2, 3, 4 to 6, and ≥ 7 months after surgery. The mean signal-to-noise ratios of the bone tunnel walls in the femur and tibia from the digital data were measured and compared for the anterior and posterior walls.

Results

The signal-to-noise ratio of the posterior wall of the femoral bone tunnel was significantly higher than that of the anterior wall in each group. On the tibial side, the signal-to-noise ratio of the anterior wall was significantly higher than that of the posterior wall at ≥4 months after surgery.

Conclusions

This study showed that the blood flow after anterior cruciate ligament reconstruction to the femoral bone tunnel is maintained from the posterior wall, and is maintained to the tibial side from the anterior wall 4 months postoperatively. Revascularization to the bone tunnel wall after anterior cruciate ligament reconstruction may relate to the distance from the vessels.

Maturity Progression of the Entire Anterior Cruciate Ligament Graft of Insertion-Preserved Hamstring Tendons by 5 Years: A Prospective Randomized Controlled Study Based on Magnetic Resonance Imaging Evaluation

BACKGROUND

It has been reported that insertion-preserved hamstring tendon autografts (IP-HT) have better maturity than free hamstring tendon autografts (FHT) at 2 years after anterior cruciate ligament reconstruction (ACLR); however, whether insertion preservation improves the maturity of the entire autograft and clinical outcomes at 5 years after ACLR is still unclear.

PURPOSE

To investigate the clinical outcomes and maturity of different segments using insertion-preserved and free hamstring tendon autografts up to 5 years after ACLR.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

45 patients who underwent isolated ACLR with hamstring tendon autografts were enrolled and randomized into 2 groups. The study group had ACLR with IP-HT, whereas the control group had ACLR with FHT. The International Knee Documentation Committee and Tegner scores, Lysholm activity score, and KT-1000 arthrometer measurements were evaluated preoperatively and at 6, 12, 24, and 60 months postoperatively. Three-dimensional-reconstruction MRI examinations were performed at 6, 12, 24, and 60 months to evaluate the signal/noise quotient (SNQ) values of femoral tunnel graft, intra-articular graft, and tibial tunnel graft.

RESULTS

At 60 months, the SNQ values of the intra-articular and tunnel sections for the grafts in both groups showed no difference; the clinical outcomes were improved compared with before surgery (P < .001) and were similar in both groups. In the early stage, all graft segments in the IP-HT group had lower SNQ values than those of the FHT group. At 6 months, the entire graft in the FHT group and the femoral tunnel section in the IP-HT group had the maximum SNQ values, whereas the femoral tunnel graft had the highest SNQ value compared with intra-articular and tibial tunnel graft in each group. SNQ values of the intra-articular and tibial tunnel graft in the IP-HT group had no significant change within 60 months.

CONCLUSION

All patients had similar clinical outcomes and graft maturity at 60 months postoperatively. The SNQ values and progressions varied at different graft sites and were highest for the femoral tunnel graft. All significantly changing SNQ values reached the maximum value at 6 months. Compared with FHT autograft, the graft maturity of IP-HT autograft recovered earlier and appeared more stable within the 60-month follow-up; however, no significant association was found between graft maturity and clinical scores.

Morphological Changes of the Femoral Tunnel and Their Correlation With Hamstring Tendon Autograft Maturation up to 2 Years After Anterior Cruciate Ligament Reconstruction Using Femoral Cortical Suspension

BACKGROUND

Graft healing within the femoral tunnel after anterior cruciate ligament reconstruction (ACLR) using suspensory fixation could be reflected in graft maturation and tunnel morphological changes. However, the correlation between graft maturation and femoral tunnel changes remains unclear.

PURPOSE

To quantitatively evaluate femoral tunnel morphological changes and graft maturation and to analyze their correlation after ACLR using femoral cortical suspension.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Patients who underwent single-bundle ACLR with a hamstring tendon autograft using femoral cortical suspension were included. Preoperative and postoperative (at 6, 12, and 24 months) knee function were evaluated using KT-1000 arthrometer testing, the Lysholm knee scoring scale, and the International Knee Documentation Committee (IKDC) questionnaire. At 1 day, 6 months, 12 months, and 24 months after ACLR, 3-dimensional magnetic resonance imaging was performed to observe the morphology of the femoral tunnel and to evaluate graft maturation using the graft signal/noise quotient (SNQ). The Pearson product moment correlation coefficients (r) of femoral tunnel radii versus clinical outcomes and graft SNQs at last follow-up were analyzed.

RESULTS

A total of 22 patients completed full follow-up. KT-1000 arthrometer, Lysholm, and IKDC scores improved over time postoperatively, but no significant improvement was seen after 12 months (P < .05). The radius of the tunnel containing the graft and the SNQs of the femoral intraosseous graft and intra-articular graft were the highest at 6 months, and they decreased by 24 months but remained higher than their 1-day postoperative values (P < .05). Expansion mainly occurred at the anteroinferior wall of the femoral tunnel. The tunnel aperture radius was positively correlated with SNQs of the intraosseous graft (r = 0.591; P < .05) and intra-articular graft (r = 0.359; P < .05) but not with clinical outcomes.

CONCLUSION

After ACLR using suspensory fixation, morphological changes of the femoral tunnel were mainly observed in the part of the tunnel containing the graft, which expanded at 6 months and reduced by 24 months. Expansion mainly occurred at the anteroinferior wall of the femoral tunnel. Femoral tunnel expansion was correlated with inferior graft maturation but not with clinical outcomes.

Japanese Orthopaedic Association (JOA) clinical practice guidelines on the management of anterior cruciate ligament injury - Secondary publication

BACKGROUND

This clinical guideline presents recommendations for the management of patients with anterior cruciate ligament (ACL) injury, endorsed by the Japanese Orthopaedic Association (JOA) and Japanese Orthopaedic Society of Knee, Arthroscopy and Sports Medicine (JOSKAS).

METHODS

The JOA ACL guideline committee revised the previous guideline based on "Medical Information Network Distribution Service Handbook for Clinical Practice Guideline Development 2014", which proposed a desirable method for preparing clinical guidelines in Japan. Furthermore, the importance of "the balance of benefit and harm" was also emphasized. This guideline consists of 21 clinical questions (CQ) and 23 background questions (BQ). For each CQ, outcomes from the literature were collected and evaluated systematically according to the adopted study design.

RESULTS

We evaluated the objectives and results of each study in order to make a decision on the level of evidence so as to integrate the results with our recommendations for each CQ. For BQ, the guideline committee proposed recommendations based on the literature.

CONCLUSIONS

This guideline is intended to be used by physicians, orthopedic surgeons, physical therapists, and athletic trainers managing ACL injuries. We hope that this guideline is useful for appropriate decision-making and improved management of ACL injuries.

Assessment of Anterior Cruciate Ligament Graft Maturity With Conventional Magnetic Resonance Imaging: A Systematic Literature Review

Background:

Magnetic resonance imaging (MRI) signal intensity (SI) measurements are being used increasingly in both clinical and research studies to assess the maturity of anterior cruciate ligament (ACL) grafts in humans. However, SI in conventional MRI with weighted images is a nonquantitative measure dependent on hardware and software.

Purpose:

To conduct a systematic review of studies that have used MRI SI as a proxy for ACL graft maturity and to identify potential confounding factors in assessing the ACL graft in conventional MRI studies.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic review was conducted by searching the MEDLINE/PubMed, Scopus, and Cochrane Library electronic databases according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines to identify studies that examined the healing of the intra-articular portion of the ACL graft by assessing SI on MRIs.

Results:

A total of 34 studies were selected for inclusion in this systematic review. The MRI acquisition techniques and methods to evaluate the ACL graft SI differed greatly across the studies. No agreement was found regarding the time frames of SI changes in MRI reflecting normal healing of the ACL tendon graft, and the graft SI and clinical outcomes after ACL reconstruction were found to be poorly correlated.

Conclusion:

The MRI acquisition and evaluation methods used to assess ACL grafts are very heterogeneous, impeding comparisons of SI between successive scans and between independent studies. Therefore, quantitative MRI-based biomarkers of ACL graft healing are greatly needed to guide the appropriate time of returning to sports after ACL reconstruction.

Feasibility of T1rho and T2 map magnetic resonance imaging for evaluating graft maturation after anatomic double-bundle anterior cruciate ligament reconstruction

Background

Although T1rho and T2 map magnetic resonance imaging (MRI) have been perceived as useful diagnostic modalities for cartilage degeneration, no studies have assessed whether these two sequences are useful for monitoring ACL graft maturation after ACL reconstruction. The present study examined whether the two sequences reflect graft function and maturation after ACL reconstruction.

Methods

Twenty consecutive patients who consented to undergo MRI at 3, 6, and 12 months after double-bundle ACL reconstruction were enrolled. MRI was performed using T1 rho and T2 map sequences in a single session. Temporal changes in T1rho and T2 values of a purely tendinous portion of graft were assessed at each time point. Correlations were analyzed between T1rho or T2 map values and clinical results, including anteroposterior laxity at 2 and 4 years postoperatively, pivot shift test results at 4 years, and graft tension on second-look arthroscopy. Separate analyses were performed for the anteromedial bundle (AMB) and posterolateral bundle (PLB).

Results

T1rho sequence was able to visualize the tendinous portions of AMB and PLB more clearly than T2 map sequence even on gray-scale images. Mean T1rho and T2 map values gradually decreased during the first operative year, but the trend was more prominent and consistent for T1rho values than for T2 map values. Correlation analysis revealed that T1rho and T2 map values at 1 year correlated significantly with anteroposterior laxity at 2 and 4 years. This trend was found in both AMB and PLB. Both T1rho and T2 map values failed to exhibit a statistical correlation with arthroscopic findings of graft tension.

Conclusions

The present study was the first trial to assess the feasibility of T1rho and T2 map sequences to objectively monitor the course of graft maturation after ACL reconstruction. Both sequences successfully detected purely tendinous portions of graft, and mean values gradually decreased during the first year postoperatively. Both values at 1 year correlated significantly with anteroposterior laxity of the knee joint at 4 years, indicating that the values reflected graft fate.

Inferior graft maturity in the PL bundle after autograft hamstring double-bundle ACL reconstruction

PURPOSE

The purpose of this study was to evaluate the signal/noise quotient (SNQ) for graft maturation and the serial changes observed in the magnetic resonance imaging (MRI) findings after double-bundle (DB) anterior cruciate ligament (ACL) reconstruction using a hamstring tendon autograft at a minimum of 5 years after surgery.

METHODS

Forty-five patients who underwent DB ACL reconstruction between 2007 and 2010 were included in this prospective study. All participants underwent postoperative MRI at 3 weeks and 3, 6, 9 and 12, 18, 24, 36, 48 and 50 months. The signal intensity (SI) characteristics of the reconstructed graft were evaluated on oblique axial proton density-weighted MR imaging (PDWI) perpendicular to the grafts. The signal/noise quotient (SNQ) was calculated to quantitatively determine the normalized SI. The SNQ of the AMB and PLB was evaluated separately.

RESULTS

The mean SNQ of the AM bundle (AMB) continued to increase until 6 months after surgery (5.2 ± 1.2), and then gradually decreased and became well stabilized by 18 months (3.3 ± 0.5), after which it remained unchanged. On the other hand, the mean SNQ of the PL bundle (PLB) continued to increase until 9 months after surgery (6.2 ± 1.1), and then decreased incrementally and became well stabilized by 24 months (4.1 ± 0.5). The SI of PLB was significantly higher than that of AMB between 3 and 24 months (p = 0.04, 0.03, 0.01, 0.04, 0.02 and 0.03, respectively).

CONCLUSIONS

These results indicate that at least 18 months is needed after ACL reconstruction to sufficiently restore the SI of the AMB, while at least 24 months are needed to for the PLB. The SI of the PLB was significantly higher than that of the AMB at 3-24 months after surgery, indicating that the PLB showed inferior graft maturity to the AMB until 24 months after surgery. For clinical relevance, the correct understanding of serial changes in graft maturation may potentially be used in decision-making regarding a return to sports.

LEVEL OF EVIDENCE

Prospective case series, Level IV.

Comparison of F18-Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography and Dynamic Contrast-Enhanced Magnetic Resonance Imaging as Markers of Graft Viability in Anterior Cruciate Ligament Reconstruction

BACKGROUND

F18-fluorodeoxyglucose positron emission tomography/computed tomography (F18-FDG PET/CT) can be used to assess changes in the metabolism of an anterior cruciate ligament (ACL) graft as it is undergoing "ligamentization." Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) is the preferred modality for noninvasive assessment of graft structure and graft vascularity.

PURPOSE

To compare the use of F18-FDG PET/CT and DCE-MRI to assess ligamentization within the ACL graft and correlate the results with clinical tests.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

Among 30 recruited patients, 27 patients (3 females and 24 males) completed 2 follow-up assessments at a mean of 125 ± 22 days and 259 ± 38 days after arthroscopic ACL reconstruction. At both assessments, anterior drawer test, Lachman test, and Lysholm scoring (LS) were conducted. Images from F18-FDG PET/CT and MRI were analyzed qualitatively and quantitatively (maximum standardized uptake value [SUVmax], SUVmax ratio to the contralateral side [SUVmax CL], normalized enhancement [NE]) in 3 zones: femoral, intra-articular (IA), and tibial. Of the 27 recruited patients, 1 patient had reinjury due to a fall. Therefore, 26 patients were considered for the final analysis.

RESULTS

A significant improvement ( P = .0001) was found in median LS, from 78.5 (range, 62-90) to 94.5 (range, 84-100), at the second follow-up. All grafts were found to be viable on PET/CT and vascularized on MRI. All grafts were seen as continuous on MRI, with exception of 1 graft at the second follow-up. Dynamic MRI identified single-vessel supply to all of the grafts at the first follow-up and multiple-vessel supply in 10 patients at the second follow-up. Reduction in the median SUVmax, SUVmax CL, and NE at second follow-up was seen in all 3 zones. Only SUVmax CL in the IA zone showed a significant reduction ( P = .032); patients with excellent LS at the second follow-up showed significantly higher reduction ( P = .005) than patients with good LS. NE in the IA zone was correlated (0.39; P = .048) with LS only at the first follow-up, whereas SUVmax CL (-0.52; P = .006) and SUVmax (-0.49, P = .010) in the IA zone negatively correlated with LS at the second follow-up only. No correlation was observed between PET/CT and MRI parameters.

CONCLUSION

Glucose metabolism and vascularity in the graft tissue can be used to assess ligamentization of ACL graft. A viable and vascularized graft at first follow-up is associated with good to excellent final outcome, regardless of LS at this stage. Since no correlation was observed between PET/CT and MRI parameters, they may be assessing different domains of the same process. Higher NE in the IA zone at the first follow-up and lower SUVmax CL in the same region at second follow-up are associated with better outcome.

Advanced Patellar Tendinopathy Is Associated With Increased Rates of Bone-Patellar Tendon-Bone Autograft Failure at Early Follow-up After Anterior Cruciate Ligament Reconstruction

Background

Revision anterior cruciate ligament (ACL) reconstruction can be potentially devastating for a patient. As such, it is important to identify prognostic factors that place patients at an increased risk for graft failure. There are no data on the effects of patellar tendinopathy on failure of ACL reconstruction when using a bone-patellar tendon-bone (BPTB) autograft.

Purpose/Hypothesis

The purpose of this study was to investigate the association of patellar tendinopathy with the risk of graft failure in primary ACL reconstruction when using a BPTB autograft. The hypothesis was that patellar tendinopathy would result in higher rates of graft failure when using a BPTB autograft for primary ACL reconstruction.

Study Design

Cohort study; Level of evidence, 3.

Methods

All patients undergoing ACL reconstruction at a single institution from 2005 to 2015 were examined. A total of 168 patients undergoing primary ACL reconstruction with a BPTB autograft were identified. Patients' magnetic resonance imaging scans were reviewed for the presence and grade of patellar tendinopathy by 2 musculoskeletal fellowship-trained radiologists; both were blinded to the aim of the study, patient demographics, surgical details, and outcomes. Patients were divided into 2 groups: failure (defined as presence of symptomatic laxity or graft insufficiency) and success of the ACL graft. Statistical analyses were run to examine the association of patellar tendinopathy with failure of ACL reconstruction using a BPTB autograft.

Results

At a mean follow-up of 18 months, there were 7 (4.2%) patients with graft failure. Moderate or severe patellar tendinopathy was associated with ACL graft failure (P = .011). Age, sex, and side of reconstruction were not associated with the risk of graft failure, although the majority of patients who failed were younger than 20 years. The use of patellar tendons with moderate to severe tendinopathy was associated with a relative risk of ruptures of 6.1 (95% CI, 1.37-27.34) as compared with autograft tendons without tendinopathy.

Conclusion

Moderate or severe patellar tendinopathy significantly increases the risk of graft failure when using a BPTB autograft for primary ACL reconstruction. Patellar tendinopathy should be considered when determining the optimal graft choice for patients undergoing primary ACL reconstruction with autograft tendons.

Contrast-Enhanced MRI Evaluation of Bone-Patellar Tendon-Bone and Hamstring ACL Autograft Healing in Humans: A Prospective Randomized Study

Background:

Gadopentetate dimeglumine–enhanced magnetic resonance imaging (MRI), or gadolinium-enhanced MRI, was used to prospectively study the postoperative course of bone–patellar tendon–bone (BPTB) and combined semitendinosus and gracilis (STG) tendon autografts following arthroscopically assisted reconstruction of the anterior cruciate ligament (ACL) in humans. Gadopentetate dimeglumine is a contrast agent that has been shown to enhance the signal of vascularized tissue when examined by MRI.

Purpose:

To prospectively determine and compare the pattern and timing of autograft revascularization following arthroscopically assisted ACL reconstruction by BPTB or STG autografts.

Study Design:

Randomized controlled trial; Level of evidence, 1.

Methods:

A total of 73 patients (63 males, 10 females) with ACL tears who were scheduled to undergo reconstruction consented to participate in this study. The patients were randomized to receive arthroscopically assisted reconstruction of the ACL employing either BPTB or STG autografts. Gadolinium-enhanced MRI scans were scheduled at 3-month intervals during the first postoperative year to assess the integrity, timing, and pattern of enhancement of the ACL graft. The temporal sequence and morphologic characteristics of imaged signals were compared for both types of ACL reconstructions.

Results:

Based on all knees with 1 exception, there were no statistically significant differences in gadopentetate dimeglumine–mediated graft enhancement grade observed between BPTB and STG autografts.

Conclusion:

The results suggest that autograft revascularization probably varies in intensity and location during the time course of graft healing. The interval signal changes observed 3 to 9 months, but especially 6 to 9 months, postoperatively are due to increased contrast uptake as a reflection of ongoing neovascularization during the process of ligamentization.

A Randomized Clinical Trial to Evaluate Attached Hamstring Anterior Cruciate Ligament Graft Maturity With Magnetic Resonance Imaging

BACKGROUND

The hamstring tendons are commonly harvested for anterior cruciate ligament (ACL) reconstruction with detachment of the tibial insertion. Retaining the insertion may help to preserve vascularity and viability of the graft and bypass the stages of avascular necrosis and revascularization, which might be beneficial to graft maturity.

PURPOSE

To investigate and compare graft maturity by magnetic resonance imaging (MRI) after ACL reconstruction with preservation or detachment of hamstring tendon tibial insertion at up to 2 years.

STUDY DESIGN

Randomized controlled trial; Level of evidence, 2.

METHODS

Forty-five patients (age range, 18-45 years) undergoing isolated ACL reconstruction with hamstring tendon were enrolled and randomized to 2 groups. The tibial insertion of the hamstring tendon was preserved in the study group (n = 21) and detached in the control group (n = 24). Patients had follow-up at 3, 6, 12, and 24 months, which consisted of the following: (1) clinical examination and (2) MRI evaluation of graft signal intensity based on signal/noise quotient (SNQ) values. Finally, 18 patients in the study group and 19 in the control group received full follow-up evaluation (ie, at all 4 time points).

RESULTS

All knees acquired full range of motion at 24 months without significant laxity. At each time point, the KT-1000 arthrometer revealed no significant difference between groups; the clinical scores significantly improved in both groups, although the difference between groups was not significant. In the control group, the SNQ value increased from 3 months, peaked at 6 months, and then decreased (3 months, 21.4 ± 12.7; 6 months, 25.6 ± 12; 12 months, 18.3 ± 7.7; 24 months, 15.3 ± 6.3). However, the insertion-preserved graft in the study group maintained relatively lower and unchanged signal intensity throughout all time points (3 months, 15.0 ± 11.2; 6 months, 14.9 ± 6.3; 12 months, 12.6 ± 7.0; 24 months, 14.6 ± 7.0). Between groups, there was no significant difference at 3 or 24 months ( P = .11 and .75, respectively), while the SNQ values were significantly lower in the study group versus the control group at 6 and 12 months ( P = .002 and .02, respectively).

CONCLUSION

The insertion-detached hamstring tendon grafts underwent a significantly increasing change in signal intensity during the first 2 years after ACL reconstruction, while the insertion-preserved grafts kept a relatively lower and unchanged signal intensity. The difference was most significant at 6 and 12 months postoperatively.

MRI-based tendon bone healing is related to the clinical functional scores at the first year after anterior cruciate ligament reconstruction with hamstring tendon autograft

PURPOSE

The correlation between tendon bone healing and clinical functional scores after anterior cruciate ligament reconstruction (ACLR) using four-stranded hamstring tendon autograft has rarely being reported. The purpose of this study was to determine the correlation between magnetic resonance imaging (MRI)-based tendon bone healing and clinical functional scores after ACLR using hamstring tendon.

METHODS

Thirty-eight patients with ACLR using four-stranded hamstring tendon autograft were included in this prospective study in the authors' hospital from 2013 to 2014. All patients were performed Tegner, Lysholm, International Knee Documentation Committee (IKDC) subjective scores, KT-1000 and MRI examinations in 3, 6, 12 months after the operation, respectively. According to MRI, the healing degree of tendon bone was divided into five grades, and the healing degree of the tendon at different time points was evaluated. Moreover, the correlations between the clinical scores and tendon bone healing level at 12 months after the operation were determined.

RESULTS

The Tegner, Lysholm, and IKDC scores of all patients were gradually improved over time after ACLR, and the degree of tendon bone healing was gradually increased. Moreover, there were significantly positive correlations between the level of tendon bone healing and the clinical functional scores at 12 months after the operation.

CONCLUSION

The clinical functional scores and the degree of tendon bone healing were gradually improved over time after ACLR. Moreover, there were significant positive correlations between the level of tendon bone healing and clinical functional scores of knee joint at the first year after the operation.

LEVEL OF EVIDENCE

III.

Hamstring Graft Incorporation According to the Length of the Graft Inside Tunnels

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction with a quadrupled semitendinosus (ST4) graft is an evolution of the standard technique with 2 hamstring tendons (semitendinosus + gracilis [STG]). However, there is no published comparison of how well these 2 types of hamstring grafts are incorporated into the bone tunnels. Because the ST4 graft is shorter, there is less graft material inside the tunnels.

PURPOSE

To use magnetic resonance imaging (MRI) to compare graft incorporation in the tibial bone tunnels 1 year after ACL reconstruction with either an STG graft or ST4 graft.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Sixty-two patients who underwent ACL reconstruction were enrolled prospectively: 31 with an ST4 graft and 31 with an STG graft. The same surgical technique, fixation method, and postoperative protocol were used in both groups. Graft incorporation and ligamentization were evaluated with MRI after 1 year of follow-up. The following parameters were evaluated: signal-to-noise quotient (SNQ), tibial tunnel enlargement, signal intensity at the bone-graft interface, and graft signal according to the Howell scale. The number of participants needed to show that the mean SNQ did not differ between the 2 techniques was 31 in each group (with a 1-sided alpha of 2.5% and a 1-sided beta of 10.0%). The Student t test was used to compare the distribution of continuous secondary endpoints.

RESULTS

The mean SNQ was 5.2 ± 4.5 for the STG group and 5.9 ± 3.7 for the ST4 group ( P = .5100). The mean tibial tunnel widening was 93.7% ± 51.7% for the STG group versus 80.0% ± 42.9% for the ST4 group ( P = .2605). The groups did not differ in signal intensity at the bone-graft interface ( P = .7502) or in graft signal according to the Howell scale ( P = .4544).

CONCLUSION

At the 1-year postoperative follow-up, incorporation and ligamentization of the STG and ST4 grafts were the same based on MRI analysis. The results were at least as good with the ST4 technique as with the standard STG technique in terms of incorporation and ligamentization.

MRI-based ACL graft maturity does not predict clinical and functional outcomes during the first year after ACL reconstruction

PURPOSE

To determine whether magnetic resonance image (MRI)-based graft maturity predicts clinical and functional scores during the first year after ACL reconstruction.

METHODS

Patients with unilateral ACL reconstruction were prospectively invited to participate in this study, and they were examined using a 3.0-T MRI scan at 3, 6, and 12 months after the operation. Clinical examinations were performed on the same day, including subjective functional examinations, physical examinations and the KT-1000 test. MRI measurements were focused on the graft signal intensity of the ACL graft using the signal/noise quotient value from a region of interest analysis.

RESULTS

Finally, a total of 38 participants with ACL reconstruction were recruited for this study, including 21 with autograft tendons and 17 with allograft tendons. Generally, the signal/noise quotient values of the ACL grafts increased from 3 to 6 months and then decreased from 6 to 12 months. There was no significant association between graft signal/noise quotient value and IKDC, Lysholm, or Tegner scores at each time point. Graft signal/noise quotient value had a significant positive association with ATTD for the cohort (p = 0.002) and for the autograft group (p = 0.004) at 3 months. However, there was no significant association between graft signal/noise quotient value and ATTD at 6 or 12 months, respectively.

CONCLUSION

The MRI-based graft maturity does not have the ability to predict clinical and functional outcomes in patients at the first-year follow-up. Graft maturity should not be used as an objective test to determine the appropriate time to return to sports during the first year after ACL reconstruction. The results from this study will allow clinicians to determine graft-specific health to determine whether the graft is healed enough to return to sports during the first postoperative year.

LEVEL OF EVIDENCE

III.

Comparison of transtibial and retrograde outside-in techniques of anterior cruciate ligament reconstruction in terms of graft nature and clinical outcomes: a case control study using 3T MRI

INTRODUCTION

This study was performed to compare ACL graft maturation and morphologies using MRI between trans-tibial (TT) and retrograde outside-in (OI) techniques, and to compare clinical outcomes between the two groups.

MATERIALS AND METHODS

Patients underwent single-tunnel ACL reconstruction using quadrupled hamstring autografts, with the TT technique used on 42 patients (TT group) and the retrograde OI technique used on 39 patients (OI group). All patients were examined with 3 T MRI at 6 months (between 5 and 7 months) after surgery. The signal intensity of the reconstructed graft was analyzed and compared between the two groups, using the signal/noise quotient (SNQ), the orientation of the ACL graft and the tibial tunnel location of the graft. The SNQ value is indicative of graft maturation, and the orientation of the graft and the tibial tunnel location of the graft represent graft morphology. Clinical evaluation was performed before the surgery and 2 years or more after the surgery.

RESULTS

The mean SNQ value of the TT group was significantly (P = 0.030) lower than that of the OI group. The mean sagittal ACL angle (P < 0.001) and the mean coronal ACL angle (P < 0.001) were more vertical in the TT group. The tibial tunnel aperture was located at a significantly (P < 0.001) more posterior position in the TT group. There was no statistically significant difference in the clinical results between the two groups.

CONCLUSIONS

The OI technique showed a more anteriorly positioned tibial tunnel and a more oblique graft orientation in both sagittal and coronal planes. However, in comparison with the TT group, a significantly higher SNQ value was noticed in the follow-up MRI of the OI group at 6 months, although clinical results of the two groups were not significantly different during at least the 2-year follow-up.

The effect of smoking on ACL reconstruction: a systematic review

OBJECTIVE

Anterior cruciate ligament reconstruction (ACLR) depends on proper healing of the graft or bone plug at the cellular level. The effect of cigarette smoke on ACLR was not commonly reported until recently. The primary purpose of this review was to determine if smoking has a negative effect on subjective or objective outcome scores after ACLR. The secondary purpose was to identify any increased risk of complications, infection, ACL re-tear, or revision procedures.

METHODS

A systematic literature review of the MEDLINE, SCOPUS and PubMed databases was performed to identify all studies that compared outcomes of ACLR surgery between smokers and nonsmokers. The frequency-weighted mean was calculated for outcome measures that were similar across several studies.

RESULTS

Seventeen studies were identified that met inclusion criteria for patients undergoing ACLR (mean age, 26.8 years) with a mean follow-up of 37 months. Smokers had significantly worse subjective outcome measures and worse side-to-side difference in anterior translation compared to non-smokers (2.68 mm vs 1.89 mm, respectively). In 2 studies, smokers were found to have a significantly higher risk of developing an infection and VTE (venous thromboembolism) post-operatively. The evidence for the effect of smoking on risk for subsequent re-tear is mixed. No study reported a higher rate of development of radiographic knee osteoarthritis among smokers compared to nonsmokers.

CONCLUSIONS

Cigarette smoke is associated with significantly worse clinical outcome scores, an increase in anterior translation, and increased complication rates after ACL reconstruction. These findings may help orthopaedic surgeons better inform their patients about the potential negative effects of smoking on the outcomes of ACL reconstruction.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Bracing can partially limit tibial rotation during stressful activities after anterior crucial ligament reconstruction with a hamstring graft

BACKGROUND

Hamstring graft has substantial differences with BPTB graft regarding initial mechanical strength, healing sequence, and vascularization, which may imply that a different approach during rehabilitation period is required. The purpose of this study was to investigate the influence of knee bracing on tibial rotation in ACL-reconstructed patients with a hamstring autograft during high loading activities. The hypothesis was that there would be a decrease in tibial rotation in the ACL-reconstructed braced knee as compared to the unbraced knee.

METHODS

Twenty male patients having undergone unilateral ACL reconstruction with a semitendinosus/gracilis autograft were assessed. Kinematic data were collected with an eight-camera optoelectronic system during two stressful tasks: (1) descending from a stair and subsequent pivoting; and (2) landing from a platform and subsequent pivoting. In each patient, three different experimental conditions were evaluated: (A) wearing a prophylactic brace (braced condition); (B) wearing a patellofemoral brace (sleeved condition); (C) without brace (unbraced condition). The intact knee without brace served as a control.

RESULTS

Tibial rotation was significantly lower in the intact knee compared to all three conditions of the ACL-reconstructed knee (P≤0.01 for both tasks). Presence of a brace or sleeve resulted in lower tibial rotation than in the unbraced condition (p=0.003 for descending/pivot and P=0.0004 for landing/pivot). The braced condition resulted in lower rotation than the sleeved condition for descending/pivoting (P=0.031) while no differences were found for landing/pivoting (P=0.230).

CONCLUSION

Knee bracing limited the excessive tibial rotation during pivoting under high loading activities in ACL-reconstructed knees with a hamstring graft. This partial restoration of normal kinematics may have a potential beneficial effect in patients recovering from ACL reconstruction with a hamstring autograft.

LEVEL OF EVIDENCE

Level III, case-control therapeutic study.

Evidence-based clinical practice update: practice guidelines for anterior cruciate ligament rehabilitation based on a systematic review and multidisciplinary consensus

AIM

The Royal Dutch Society for Physical Therapy (KNGF) instructed a multidisciplinary group of Dutch anterior cruciate ligament (ACL) experts to develop an evidence statement for rehabilitation after ACL reconstruction.

DESIGN

Clinical practice guideline underpinned by systematic review and expert consensus.

DATA SOURCES

A multidisciplinary working group and steering group systematically reviewed the literature and wrote the guideline. MEDLINE and the Cochrane Library were searched for meta-analyses, systematic reviews, randomised controlled trials and prospective cohort studies published between January 1990 and June 2015.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Included literature must have addressed 1 of 9 predetermined clinical topics: (1) preoperative predictors for postoperative outcome, (2) effectiveness of physical therapy, (3) open and closed kinetic chain quadriceps exercises, (4) strength and neuromuscular training, (5) electrostimulation and electromyographic feedback, (6) cryotherapy, (7) measurements of functional performance, (8) return to play and (9) risk for reinjury.

SUMMARY

Ninety studies were included as the basis for the evidence statement. Rehabilitation after ACL injury should include a prehabilitation phase and 3 criterion-based postoperative phases: (1) impairment-based, (2) sport-specific training and (3) return to play. A battery of strength and hop tests, quality of movement and psychological tests should be used to guide progression from one rehabilitation stage to the next. Postoperative rehabilitation should continue for 9-12 months. To assess readiness to return to play and the risk for reinjury, a test battery, including strength tests, hop tests and measurement of movement quality, should be used.

Graft bending angle is correlated with femoral intraosseous graft signal intensity in anterior cruciate ligament reconstruction using the outside-in technique

BACKGROUND

The purposes of this study were as follows: 1) to determine the correlation between the bending angle of the anterior cruciate ligament (ACL) graft at the femoral tunnel and the magnetic resonance imaging (MRI) signal intensity of the ACL graft and 2) to analyze the difference in the MRI signal intensity of the reconstructed ACL graft in different areas of the graft after single-bundle hamstring autograft ACL (SB ACL) reconstruction using an outside-in (OI) technique with bone-sparing retro-reaming.

METHODS

Thirty-eight patients who underwent SB ACL reconstruction with the hamstring tendon autograft using the OI technique were enrolled in this study. All patients were assessed using three-dimensional computed tomography (CT) to evaluate femoral tunnel factors, including tunnel placement, tunnel length, tunnel diameter, and femoral tunnel bending angle. At a mean of 6.3±0.8months after surgery, 3.0-T MRI was used to evaluate the graft signal intensity using signal/noise quotient for high-signal-intensity lesions.

RESULTS

Among various femoral tunnel factors, only the femoral tunnel bending angle in the coronal plane was significantly (p=0.003) correlated with the signal/noise quotient of the femoral intraosseous graft. The femoral intraosseous graft had significantly (p=0.009) higher signal intensity than the other graft zone. Five cases (13.2%) showed high-signal-intensity zones around the femoral tunnel but not around the tibial tunnel.

CONCLUSION

After ACL reconstruction using the OI technique, the graft bending angle was found to be significantly correlated with the femoral intraosseous graft signal intensity, indicating that increased signal intensity by acute graft bending might be related to the maturation of the graft.

LEVEL OF EVIDENCE

This was a retrospective comparative study with Level III evidence.

Quantitative evaluation of revascularization at bone tunnels and grafts with contrast-enhanced magnetic resonance angiography after anterior cruciate ligament reconstruction

PURPOSE

Quantitative evaluation of vascular ingrowth to the bone tunnel walls and tendon graft after anterior cruciate ligament reconstruction for up to two years post-surgery using magnetic resonance angiography (MRA).

METHODS

The study population consists of 100 patients that underwent reconstruction with multi-stranded semitendinosus tendons. The patients were retrospectively divided into those that underwent MRA two, three, four to six, and ≥ seven months after surgery (46, 17, 16, and 21 patients, respectively). Digital imaging and communication in medicine (DICOM) MRA images were imported into image processing software (OsiriX®), and the mean signal-to-noise ratio (SNR) of the bone tunnel walls in the femur and tibia and tendon graft parenchyma in the bone tunnels were measured.

RESULTS

On MRA, the signal intensities of the bone tunnel walls in the femur and tibia (12.6 ± 3.41 and 10.7 ± 3.04) were greater than that in the tendon graft (2.65 ± 1.94 and 2.50 ± 2.02, respectively) at two months after surgery. At three months after surgery, the intensities of the tendon grafts (6.25 ± 2.18 and 5.77 ± 1.57, respectively) were greater than those of the bone tunnel wall (2.56 ± 1.29 and 2.50 ± 1.11, respectively). At four to six months, the intensities in the bone tunnel wall were 1.76 ± 0.73 and 1.62 ± 0.72, respectively, and those in the tendon graft were 5.01 ± 2.11 and 4.01 ± 2.35, respectively. At ≥ seven months after surgery, the intensities in the bone tunnel wall were 1.36 ± 0.63 and 1.21 ± 0.87, respectively, and those in the tendon graft were 4.25 ± 1.87 and 3.44 ± 1.99, respectively.

CONCLUSION

Blood flow was seen around the bone tunnel on the femoral and tibial sides two months after ACL reconstruction and in the tendon graft parenchyma three months after surgery. The remodeling process continued after seven months.

Magnetic resonance angiography evaluation of the bone tunnel and graft following ACL reconstruction with a hamstring tendon autograft

PURPOSE

In this study, magnetic resonance angiography (MRA) was performed in the early phase after anterior cruciate ligament (ACL) reconstruction to analyse the changes in nutrient blood vessels and blood flow to the femoral and tibial tunnels and the intraosseous tendon grafts.

METHODS

The subjects were 30 patients who underwent single-bundle ACL reconstruction with an autogenous hamstring tendon. MRA was performed at 2, 3, and 6 months postoperatively (n = 10 at each time point). The mean overall signal-to-noise ratios (SNRs) in the tunnel regions and in the region of the tendon graft were compared in each femur and tibia.

RESULTS

Blood vessels from arteries reached the femoral and tibial tunnels 2 months postoperatively. The tunnel walls showed high signal intensity, while the intraosseous tendon grafts had lower intensity. SNRs showed significant differences between the femoral and tibial tunnels overall and the intraosseous tendon grafts. At 3 and 6 months postoperatively, the signal intensity of the tunnel walls was decreased significantly, while that of the intraosseous tendon grafts was also decreased, but not significantly. At these times, the SNRs of the femoral and tibial tunnels did not differ significantly, both overall and in the region of the intraosseous tendon grafts.

CONCLUSION

Revascularization around the femoral and tibial tunnels occurred at 2 months postoperatively, with blood flow subsequently decreasing over time until 6 months. This revascularization may be involved in bone tendon healing and maturation of the tendon graft within the bone tunnels. Evaluations of revascularization by MRA may show the maturation stage of the graft and guide medical rehabilitation.

LEVEL OF EVIDENCE

IV.

Comparison of tendon-bone healing between autografts and allografts after anterior cruciate ligament reconstruction using magnetic resonance imaging

PURPOSE

The purpose of the study is to compare tendon-bone healing between autograft tendons and allograft tendons after anterior cruciate ligament (ACL) reconstruction using 3.0T magnetic resonance imaging.

METHODS

A total of 36 participants (18 with autograft and 18 with allograft reconstruction) underwent MRI scans at least 2 years after the ACL reconstruction operation. Oblique axial images were obtained on three-dimensional dual-echo steady-state images and imported into solid modelling software for three-dimensional model reconstruction of the bone tunnel. The graft signal intensity in the tunnel, tendon-bone interface, tunnel morphology, and tunnel area was analysed using the Siemens software packages to determine the tendon-bone healing between the groups.

RESULTS

For the tunnel morphology, both groups exhibited bone tunnel enlargement either at the femoral or tibial tunnel aperture. For the tendon-bone interface, one patient in the autograft group and two patients in the allograft group exhibited a significant fibrous scar tissue bands at the tendon-bone interface. The graft signal/noise quotient values of the allograft group were higher than the autograft group. However, there was no significant difference in the tunnel area between the allograft group and the autograft group.

CONCLUSIONS

Although the autograft tendons exhibited a better remodelling effect than did the allograft tendons in the bone tunnel, there was no significant difference in the tendon-bone healing between the autograft tendons and the allograft tendons postoperatively. These findings indicate that the biomechanical effect of graft motion may play a significant role in the tunnel aperture.

LEVEL OF EVIDENCE

III.

Graft maturity of the reconstructed anterior cruciate ligament 6 months postoperatively: a magnetic resonance imaging evaluation of quadriceps tendon with bone block and hamstring tendon autografts

PURPOSE

The purpose of this study was to report the potential differences associated with graft maturity measured on magnetic resonance imaging (MRI) between quadriceps tendon with bone block and hamstring tendon autografts 6 months after ACL reconstruction.

METHODS

Twenty-six patients (15 male, 11 female; mean age 29.4 ± 17 years, range 13-46 years) who had undergone anatomic SB ACL reconstruction with either hamstring or quadriceps tendon with bone block autografts and had postoperative MRI 6 months after surgery. In 12 cases, the quadriceps tendon with bone block was used and hamstring in 14 cases. The signal/noise quotient was calculated to compare the difference between quadriceps tendon with bone block and hamstring autografts.

RESULTS

Mean signal/noise quotient is lesser in quadriceps tendon with bone block (1.74 ± 0.39) compared with HS (2.44 ± 0.61) autografts (p = 0.020). For hamstring autograft, the distal region showed a significantly lower mean signal/noise quotient value compared with middle region, and the mean signal/noise quotient value in proximal region was the highest (distal vs middle p < 0.001; middle vs proximal p = 0.007; proximal vs distal p < 0.001). The mean signal/noise quotient of proximal region in quadriceps tendon with bone block autograft was lesser than that in hamstring. The middle region of the quadriceps tendon with bone block graft demonstrated the greatest signal/noise quotient [distal vs middle p = 0.001; middle vs proximal p = 0.027; proximal vs distal (n.s.)].

CONCLUSION

The maturity of quadriceps tendon with bone block was better in comparison with hamstring 6 months after anatomic SB ACL reconstruction. This study is clinically relevant in that modifying the individual rehabilitation according to the extent of graft maturity may be necessary to optimize patient function and prevent re-injury of the ACL graft.

Clinical significance of T2*-weighted gradient-echo MRI to monitor graft maturation over one year after anatomic double-bundle anterior cruciate ligament reconstruction: a comparative study with proton density-weighted MRI

PURPOSE

This study examined the feasibility of T2*-weighted imaging (T2*WI) gradient-echo MRI to reflect actual function of the graft after anatomic double-bundle ACL reconstruction. T2*WI and proton density-weighted imaging (PDWI) were compared in the assessment of ACL grafts.

METHOD

Sixty-one patients underwent T2*WI and PDWI at 3, 6, and 12 months postoperatively. Signal intensity of the anteromedial bundle (AMB) or posterolateral bundle (PLB) graft standardized to the intensity of the PCL was defined as signal intensity ratio (SIR). Correlations between degree of knee instability and SIR were assessed for each bundle, each time point, and each sequence. The diagnostic efficacy of T2*WI sequence to detect poorly functioning knee with anteroposterior translation ≥ 4 mm was assessed.

RESULTS

Significant correlations were observed between SIR and KT values for both AMB and PLB at 12 months on T2*WI (r=0.39 and 0.53, respectively), but not on PDWI. Notably, 9 of 10 patients with poorly functioning graft showing anteroposterior translation ≥ 4 mm at 12 months formed an isolated group with high T2*WI-SIR. Six of the 10 patients displayed an increase in SIR from 6 to 12 months. Defining anteroposterior translation ≥ 4 mm at 12 months as the diagnostic standard for poorly functioning graft, increasing T2*WI-SIR offered 60% sensitivity and > 90% specificity.

CONCLUSIONS

ACL graft intensity on T2*WI is more strongly associated with actual function of the graft than that on PDWI. An increasing trend in T2*WI-SIR from 6 to 12 months postoperatively represents a possible surrogate indicator for poorly functioning grafts.

Correlation Analysis of Potential Factors Influencing Graft Maturity After Anterior Cruciate Ligament Reconstruction

Background:

Postoperatively, signal changes of the reconstructed anterior cruciate ligament (ACL) graft on magnetic resonance imaging (MRI) images commonly occurs, which may be a cause for concern. The signal intensity changes are usually expressed by signal/noise quotient (SNQ) value, representing graft maturity. To date, little is known about the factors influencing the SNQ value of the reconstructed ACL graft.

Purpose:

To evaluate ACL graft SNQ value and associated factors after ACL reconstruction.

Study Design:

Case series; Level of evidence, 4.

Methods:

Male patients who underwent ACL reconstruction using autograft or allograft tendon from September 2004 to September 2011 were randomly invited to take part in this investigation, including functional scores, physical examination, and MRI scan. The femoral side graft was fixed with Endobutton CL or Rigidfix pins, and the tibial side graft was fixed with a bio-intrafix. SNQ values of each graft were measured on MRI to represent graft maturity. Sagittal ACL angle, ACL–Blumensaat line angle, and medial and lateral posterior tibial slope (PTS) were measured using MRI 3-dimensional dual-echo steady-state images. Potential risk factors, including age, body mass index, postoperative time, Tegner activity scale (TAS), sagittal ACL angle, ACL–Blumensaat line angle, medial PTS, lateral PTS, and primary graft diameter, were tested for their association with the graft SNQ value by multivariate stepwise regression analysis.

Results:

A total of 104 male subjects (mean follow-up, 30.7 months) were examined, including 62 allograft and 42 autograft reconstructions. There was a significant association between graft SNQ and postoperative time (r = −0.431, P < .001), TAS (r = 0.295, P = .002), and ACL–Blumensaat line angle (r = −0.304, P = .002). Univariate regression analysis showed that TAS (β = 6.15, P < .001) positively correlated, postoperative time (β = −0.26, P < .001) negatively correlated, and ACL–Blumensaat line angle (β = −0.40, P = .038) negatively correlated with graft SNQ. Multivariate stepwise regression analysis showed that TAS, postoperative time, ACL–Blumensaat line angle, and age were significant independent factors associated with graft SNQ.

Conclusion:

The graft SNQ value had a significant positive correlation with physical activity level and a significant negative correlation with postoperative time in this study. Males with a shorter postoperative time and a higher physical activity level had higher graft signal intensity postoperatively.

MRI analysis of single-, double-, and triple-bundle anterior cruciate ligament grafts

PURPOSE

The purpose of the study was to evaluate the entire course of ACL grafts on coronal oblique MR images, focusing on differences in graft morphology and graft-to-tunnel healing among single-bundle (SB), double-bundle (DB), and triple-bundle (TB) reconstructions.

METHODS

Eighty-three patients underwent anatomical ACL reconstruction using the semitendinosus tendon. SB reconstruction was performed on 20 patients, DB on 29 patients, and TB on 34 patients. The anteromedial-bundle (AMB) and posterolateral-bundle (PLB) images were extracted from coronal oblique images of grafts at 6 months to visualize their entire course. Signal intensity of grafts was measured independently in three regions: (1) intra-femoral tunnel region, (2) intra-articular region, and (3) intra-tibial tunnel region, followed by calculation of the signal-to-noise quotient (SNQ). To evaluate graft-to-tunnel healing, T2-weighted images were examined for the presence of a high signal-intensity lesion between the graft and bone tunnel around the tunnel aperture.

RESULTS

AMB images showed that SB graft was thick throughout the entire course, while DB graft was thinner than SB graft. TB graft showed a fan shape approaching the tibial tunnels. The SNQ in the femoral tunnel of SB graft was significantly lower than in the DB and TB grafts. High signal-intensity lesions were frequently observed around the femoral tunnel aperture in PLB images of DB and TB grafts compared to SB grafts.

CONCLUSION

Gross morphology of TB grafts resembled that of the natural ACL. However, the graft-to-tunnel healing around the femoral tunnel seemed to be insufficient in PLB images of DB and TB compared to SB grafts.

Biomedical coatings on polyethylene terephthalate artificial ligaments

This review comprehensively covers research conducted to enhance polyethylene terephthalate (PET) artificial ligament osseointegration in the bone tunnel. These strategies, using biocompatible or bioactive coatings, had a positive effect in promoting PET ligament osseointegration by increasing bone formation and decreasing fibrous scar tissue at the ligament-to-bone interface. The improved osseointegration can be translated into a significant increase in the biomechanical pull-out loads. However, the load-to-failure of coated ligament is far lower than that of native ACL. Coatings to promote intra-articular ligamentization are also discussed in this study. Collectively, our investigations may arouse further study of the biological coating of PET artificial ligaments in order to effectively enhance ligament osseointegration and promote artificial ligament ligamentization.

Graft selection in anterior cruciate ligament reconstruction for smoking patients

BACKGROUND

There has been no previous study regarding graft selection in anterior cruciate ligament (ACL) reconstruction for smoking patients.

PURPOSE

To compare the clinical outcomes of ACL reconstruction between smokers and nonsmokers and to find an optimal graft in ACL reconstruction with regard to clinical outcomes for smoking patients.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

A total of 487 patients who underwent unilateral ACL reconstruction were retrospectively reviewed. Included patients were divided into 2 groups according to their history of smoking. Group 1 was composed of patients who had never smoked (n = 322), and group 2 consisted of patients who had reported smoking before ACL reconstruction and during rehabilitation (n = 165). Additionally, each group was divided into 4 subgroups according to the selected graft type (bone-patellar tendon-bone autograft, hamstring [semitendinosus-gracilis] tendon autograft, quadriceps tendon-bone autograft, or Achilles tendon-bone allograft). Patients were assessed for knee instability with the Lachman and pivot-shift tests as well as anterior translation measured by the KT-2000 arthrometer. Functional outcomes were evaluated with the Lysholm knee score, International Knee Documentation Committee (IKDC) subjective score, and IKDC objective grade.

RESULTS

The minimum follow-up period was 24 months. At the final follow-up evaluation, there were significant mean between-group differences regarding the side-to-side difference in anterior translation (group 1, 2.15 ± 1.11 mm; group 2, 2.88 ± 1.38 mm; P < .001), Lysholm knee score (group 1, 90.25 ± 6.18; group 2, 84.79 ± 6.67; P < .001), IKDC subjective score (group 1, 89.16 ± 5.01; group 2, 83.60 ± 7.48; P < .001), and IKDC objective grade (group 1, grade A = 151, B = 130, C = 36, D = 5 patients; group 2, grade A = 48, B = 71, C = 37, D = 9 patients; P < .001). With regard to differences in outcomes between the selected grafts within each group, the Achilles tendon-bone allograft showed the worst outcomes, with statistically significant mean differences for smoking patients in the side-to-side difference in anterior translation (3.59 ± 1.26 mm), Lysholm knee score (81.05 ± 2.82), and IKDC subjective score (79.73 ± 4.29).

CONCLUSION

Unsatisfactory outcomes with regard to stability and functional scores were shown in the smoking group compared with the nonsmoking group. In smokers, the patients receiving an Achilles tendon-bone allograft had poorer outcomes than those with autografts. The bone-patellar tendon-bone autograft is recommendable for ACL reconstruction in a smoking patient.

Is there a role for adult non-cultivated bone marrow stem cells in ACL reconstruction?

PURPOSE

To assess by magnetic resonance imaging (MRI) if adult non-cultivated bone marrow stem cells accelerate tendon-to-bone healing in the femoral tunnel, after hamstring anterior cruciate ligament (ACL) reconstruction.

METHODS

Forty-three patients underwent ACL reconstruction and were prospectively randomized into two groups: 20 patients in the experimental group (group A) with adult non-cultivated bone marrow stem cells and 23 patients in the control group (group B) without adult non-cultivated bone marrow stem cells. All patients underwent MRI of the knee at three months after surgery to evaluate the signal-to-noise ratio of the interzone.

RESULTS

There was no difference in the signal-to-noise ratio of the interzone on MRI between the experimental and the control group.

CONCLUSIONS

Adult non-cultivated bone marrow stem cells do not seem to accelerate graft-to-bone healing in ACL reconstruction. The clinical relevance of this finding is that adult non-cultivated bone marrow stem cells apparently have a limited role in ACL reconstruction.

A novel core biopsy technique for anterior cruciate ligament preserves ligament structural integrity: a porcine study

PURPOSE

The objective of this study was to validate a new technique to safely obtain core biopsy specimens of the anterior cruciate ligament (ACL) without jeopardizing the ACL's biomechanical properties.

METHODS

Eleven pairs of fresh porcine femur-ACL-tibia complexes were tested in a loading frame. The ACL of one knee was biopsied using a spring-loaded core biopsy device, whereas the contralateral ACL was tested as the control. Biomechanical properties of the biopsied and control ACLs were compared.

RESULTS

The ultimate load to failure was 1,202 N ± 171.1 N and 1,193 N ± 228.7 N (P = .8984) for biopsied and non-biopsied ACLs, respectively. No significant differences were noted for maximal elongation at failure, maximal strain, absorbed energy, and stiffness between biopsied and non-biopsied ACLs.

CONCLUSIONS

The results of this study indicate that a new ACL core biopsy technique can be performed while preserving the ligament's structural integrity.

CLINICAL RELEVANCE

The presented core biopsy technique could be regarded as a dedicated tool to elucidate the poorly understood (patho)biological processes occurring in both the native and reconstructed ACLs.

Evaluation with contrast-enhanced magnetic resonance imaging of the anterior cruciate ligament graft during its healing process: a two-year prospective study

OBJECTIVE

The aim of this study was to evaluate, with contrast-enhanced-magnetic resonance imaging (MRI), the changing imaging appearance of an anterior cruciate ligament (ACL) graft during the revascularization phase by quantitatively assessing the morphological and signal intensity changes taking place at its cross-sectional surface over time.

MATERIALS AND METHODS

Fifty patients underwent contrast-enhanced-MRI on the third postoperative day and at a mean of 6, 12, and 24 months time interval after surgery. Proton-density images were obtained to evaluate morphological and signal intensity characteristics. Oblique-axial T1-weighted images obtained before and after intravenous gadolinium administration were used for quantitative analysis. Enhancement index (EI: signal-to-noise quotient(after gadolinium)÷signal-to-noise quotient(before gadolinium)) and cross-sectional area (CSA) were calculated for two regions of interest: the transplanted graft and its surrounding hypervascular tissue, and at three distinct graft sites (intra-articular, intraosseous tibial tunnel, and intraosseous juxta screw sites). Comparisons of EI and CSA at every site and time interval were performed using analysis of variance.

RESULTS

A variable MRI appearance of the graft during the different time intervals was attributed to the varying amount of the hypervascular tissue gradually surrounding the graft. Graft EI and peripheral tissue CSA progress in a parallel, time- and site-related pattern along the graft course. The initial heterogeneity with intermediate signal intensity at the intra-articular graft site reflected intense revascularization. A slower revascularization progress was noticed at the other two intraosseously enclosed sites.

CONCLUSION

During the healing process the amount of revascularization tissue influences the MR imaging characteristics of the graft according to the examined site and the time interval after surgery. By 2 years postoperatively, revascularization completion coincides with the homogeneously low signal intensity of the graft, closely resembling native ACL.

Partial ACL reconstruction with preservation of the posterolateral bundle

INTRODUCTION

Over the past decade, our understanding of the anterior cruciate ligament (ACL) has evolved considerably. Based on this knowledge, ACL reconstruction techniques have changed and selective reconstruction procedures have been developed for partial tears. Our hypothesis was that stability and function can be restored to the knee with selective bundle reconstruction of partial ACL tears and preservation of the residual fibers.

MATERIALS AND METHODS

This was a multicenter retrospective study of 168 partial reconstructions of the anteromedial (AM) bundle of the ACL with preservation of the posterolateral (PL) bundle. All patients underwent a clinical evaluation based on the objective and subjective IKDC scores and the Lysholm score after a mean follow-up of 26 months (12-59 months). Preoperative and postoperative instrumental measurement of knee laxity was performed by arthrometer and/or by (Telos(®)) stress radiography. Statistical analysis and comparison was performed between pre- and postoperative results.

RESULTS

The preoperative and postoperative subjective IKDC scores were 63.7 and 90.5 at the final follow-up respectively (P<0.001). The preoperative and postoperative Lysholm scores were 80 and 95.5 respectively (P<0.001). Preoperatively, most patients were classified C on the objective IKDC score. At the final follow-up 92% of the patients were classified A or B (P<0.001). Differential preoperative laxity was 5.5mm (range: 0-14 mm) and 1.1mm (range: 0-4mm) at the final follow-up (P<0.00001).

DISCUSSION AND CONCLUSION

Our study confirms that selective reconstruction of the AM bundle of the ACL with preservation of the PL bundle restores stability and function to the knee. Special attention should be paid to the size of the graft used to avoid excess tissue in the intercondylar notch.

The use of layer by layer self-assembled coatings of hyaluronic acid and cationized gelatin to improve the biocompatibility of poly(ethylene terephthalate) artificial ligaments for reconstruction of the anterior cruciate ligament

In this study layer by layer (LBL) self-assembled coatings of hyaluronic acid (HA) and cationized gelatin (CG) were used to modify polyethylene terephthalate (PET) artificial ligament grafts. Changes in the surface properties were characterized by scanning electron microscopy, attenuated total reflection Fourier transform infrared spectroscopy, energy-dispersive X-ray spectroscopy, and contact angle and biomechanical measurements. The cell compatibility of this HA-CG coating was investigated in vitro on PET films seeded with human foreskin dermal fibroblasts over 7days. The results of our in vitro studies demonstrated that the HA-CG coating significantly enhanced cell adhesion, facilitated cell growth, and suppressed the expression of inflammation-related genes relative to a pure PET graft. Furthermore, rabbit and porcine anterior cruciate ligament reconstruction models were used to evaluate the effect of this LBL coating in vivo. The animal experiment results proved that this LBL coating significantly inhibited inflammatory cell infiltration and promoted new ligament tissue regeneration among the graft fibers. In addition, the formation of type I collagen in the HA-CG coating group was much higher than in the control group. Based on these results we conclude that PET grafts coated with HA-CG have considerable potential as substitutes for ligament reconstruction.