The Effect of Intraoperative Graft Coverage With Preserved Remnant Tissue on the Results of the Pivot-Shift Test After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction: Quantitative Evaluations With an Electromagnetic Sensor System

Combined over-the-top reconstruction with posterolateral bundle remnant re-tensioning in pediatric anterior cruciate ligament reconstruction: A technical note

Epiphyseal injury, particular on femoral side, is a major concern in pediatric anterior cruciate ligament (ACL) reconstruction. Therefore, the over-the-top route (OTTR) method has frequently been selected in pediatric ACL reconstruction, with good clinical results reported. However, a cadaver study reported the inferior rotational stability of the OTTR method to that of anatomical single bundle reconstruction. In recent years, a new method of reconstruction, which involves the remnant being detached, re-tensioned, and re-attached, achieved good short-term results. We developed a surgical method to restore the remnant to the posterolateral (PL) bundle footprint and obtain rotational stability in patients, thereby preserving the remnant. We hypothesized that repairing the residual remnant to the PL bundle footprint in pediatric ACL reconstruction could achieve rotational stability. This report offers the surgical techniques for PL bundle tensioning repair using remnants in the pediatric ACL OTTR procedure.

Effects of higher femoral tunnels on clinical outcomes, MRI, and second-look findings in double-bundle anterior cruciate ligament reconstruction with a minimal 5-year follow-up

BACKGROUND

To perform anatomical anterior cruciate ligament reconstruction (ACLR), tunnels should be placed relatively higher in the femoral anterior cruciate ligament (ACL) footprint based on the findings of direct and indirect femoral insertion. But the clinical results of higher femoral tunnels (HFT) in double-bundle ACLR (DB-ACLR) remain unclear. The purpose was to investigate the clinical results of HFT and lower femoral tunnels (LFT) in DB-ACLR.

METHODS

From September 2014 to February 2016, 83 patients who underwent DB-ACLR and met the inclusion and exclusion criteria were divided into HFT-ACLR (group 1, n = 37) and LFT-ACLR (group 2, n = 46) according to the position of femoral tunnels. Preoperatively and at the final follow-up, clinical scores were evaluated with International Knee Documentation Committee (IKDC), Tegner activity, and Lysholm score. The stability of the knee was evaluated with KT-2000, Lachman test, and pivot-shift test. Cartilage degeneration grades of the International Cartilage Repair Society (ICRS) were evaluated on magnetic resonance imaging (MRI). Graft tension, continuity, and synovialization were evaluated by second-look arthroscopy. Return-to-sports was assessed at the final follow-up.

RESULTS

Significantly better improvement were found for KT-2000, Lachman test, and pivot-shift test postoperatively in group 1 ( P >0.05). Posterolateral bundles (PL) showed significantly better results in second-look arthroscopy regarding graft tension, continuity, and synovialization ( P <0.05), but not in anteromedial bundles in group 1. At the final follow-up, cartilage worsening was observed in groups 1 and 2, but it did not reach a stastistically significant difference ( P >0.05). No statistically significant differences were found in IKDC subjective score, Tegner activity, and Lysholm score between the two groups. Higher return-to-sports rate was found in group 1 with 86.8% (32/37) vs. 65.2% (30/46) in group 2 ( P = 0.027).

CONCLUSION

The HFT-ACLR group showed better stability results, better PL, and higher return-to-sports rate compared to the LFT-ACLR group.

Comparison of ACL and Anterolateral Ligament Reconstruction With Isolated ACL Reconstruction Using Hamstring Autograft: Outcomes in Young Female Patients With High-Grade Pivot Shift

Background

Inferior return to sports (RTS) and functional outcomes have been reported in women after anterior cruciate ligament reconstruction (ACLR).

Purpose/Hypothesis

The purpose was to evaluate the results of combined ACLR and anterolateral ligament reconstruction (ALLR) in young women with a high-grade pivot shift (grade ≥2). It was hypothesized that combined ACLR and ALLR would result in better RTS and rotational stability than isolated ACLR.

Study Design

Cohort study; Level of evidence, 3.

Methods

Two groups were retrospectively evaluated and compared. Group I (n = 39; mean age, 31.1 ± 5.7 years) underwent isolated ACLR using hamstring autografts; group C (n = 39; mean age, 30.4 ± 6.1 years) underwent combined ACLR and ALLR. Subjective outcome measures included the International Knee Documentation Committee subjective form, Lysholm, Tegner, and ACL-Return to Sport after Injury (ACL-RSI). Objective tests included a KT-2000 arthrometer stress test, a pivot-shift test, an isokinetic strength test, a Y-balance test, and a single-leg hop test. A postoperative questionnaire was administered to determine the rates and types of RTS, quality of sports performance, and reinjury and satisfaction rates. Subjective scores and clinical tests were performed at 2 years. Magnetic resonance imaging and second-look arthroscopy were conducted during the 1- and 2-year follow-ups, respectively.

Results

The mean follow-up for groups I and C were 30.4 ± 3.9 and 29.3 ± 3.5 months, respectively (P = .194). Patients in group C had better anteroposterior (P = .001) and rotational (P = .005) stability and higher ACL-RSI scores (P = .025) than those in group I. Group C had higher composite and posteromedial reach scores on the Y-balance test than group I (P = .014 and P = .010, respectively). A total of 26 (66.7%) patients in group C and 17 (43.6%) in group I returned to their prior level of sports (P = .040). Rerupture of the ACL graft and contralateral ACL rupture occurred in 2 (5.1%) and 2 (5.1%) patients in group I, respectively, compared with no rerupture or contralateral ACL rupture in group C.

Conclusion

Combined ACLR and ALLR in young women with a high-grade pivot shift was associated with better knee stability parameters, dynamic postural stability, and psychological readiness to RTS than isolated ACLR.

Effect of a new remnant-preserving technique with anatomical double-bundle anterior cruciate ligament reconstruction on MRI-based graft maturity: a comparison cohort study

PURPOSE

To investigate the effects of a new remnant-preserving double-bundle anterior cruciate ligament reconstruction (ACLR) technique, focused on avoiding remnant damage and preserving continuity of remnants, on graft maturity using magnetic resonance imaging (MRI).

METHODS

A total of 169 patients were divided into three groups: 41 in the preservation group, 70 in the resection group, and 58 in the absent group. In the preservation group, rather than passing the graft through the remnant tissue, the graft was reconstructed such that the anteromedial and posterolateral bundles sandwiched the remnant to avoid damage to the remnant and maintain its continuity. Based on 1-year postoperative MRI, the grafts were divided into three regions: distal, middle, and proximal. The signal/noise quotient (SNQ) of each region of interest was calculated to evaluate the signal intensity of the graft and was compared among the three groups. Additionally, to identify factors influencing graft maturity, a multiple regression analysis was performed with SNQ as the dependent variable and patient demographics, bone morphology, and surgical factors as independent variables.

RESULTS

In a three-group comparison of mean SNQs, the distal region was 3.3 ± 3.4, 8.9 ± 8.3, and 9.0 ± 8.6 (p < 0.001), the middle region was 5.3 ± 3.7, 10.9 ± 11.1, and 11.3 ± 10.2 (p < 0.001), and the proximal region was 6.8 ± 4.5, 11.1 ± 8.8, and 11.7 ± 10.8 (p = 0.017), in order of the preservation, resection, and absent groups, respectively. That indicated that the remnant-preserving ACLR was more hypointense than ACLR with remnant resection or absent in all three regions. Multiple regression analysis showed that remnant preservation remained the relevant factor affecting SNQ of the graft at the distal and middle levels.

CONCLUSION

The new remnant-preserving anatomic double-bundle ACLR had significantly better graft maturity, measured by SNQ on MRI, than the remnant resection and absent groups. The remnant procedure was the relevant factor affecting graft maturity.

LEVEL OF EVIDENCE

Level III.

Differentiation Ability of Tendon-Derived Stem Cells and Histological Characteristics of Rotator Cuff Remnant on the Greater Tuberosity Degenerated With Age and Chronicity

PURPOSE

To explore and measure the presence and activity of tendon-derived stem cells (TDSCs), as well as histological changes of rotator cuff remnant by age and chronicity of the rotator cuff tear (RCT).

METHODS

154 patients with a full-thickness tear of supraspinatus and/or infraspinatus tendon were included. 52 qualified remnants of the greater tuberosity were captured through arthroscopy. TDSCs in the remnants were isolated for proliferation ability, basal gene expression, and trilineage differentiation detection. Histological characteristics were evaluated by observation of staining under a light microscope and transmission electron microscopy (TEM). To observe the effect of age, samples were divided into two groups: young (＜60 years old) and old (≥60 years old). For chronicity comparison, samples were divided into three groups: acute group (＜3 months), intermediate group (3-12 months), and chronic group (≥12 months).

RESULTS

Between age groups, the remnants in older patients were found to have lower TDSC proliferation ability (cell counting kit-8 results, old: .5325 ± .050, young: .6623 ± .196; P = .008) and basal expression of aggrecan (.630 ± .239; P = .002) and TGF-β1 (transforming growth factor-β1, .589 ± .326, P = .008), weaker ability of chondrogenic differentiation. Furthermore, the remnant tendons in chronic group was found to have weaker adipogenic and chondrogenic differentiation ability of TDSCs, lower tendon degenerative score (acute: 3.57 ± 1.902, intermediate: 5.94 ± 2.313, chronic: 6.86 ± 2.193; P = .023), increased type III collagen region ratio in insertion area (acute: 86.10% ± 8.29%, intermediate: 94.06% ± 5.36%, chronic: 98.90% ± .49%; P = .023), and larger fibril diameters.

CONCLUSION

Differentiation ability of TDSCs derived from the rotator cuff remnant was reduced with age and chronicity. Histological degeneration of remnant tendon deteriorated with chronicity. Remnant in the greater tuberosity was still alive, but those in young or acute injury patients were more active after full-thickness RCT.

CLINICAL RELEVANCE

TDSCs exist in rotator cuff remnant on the greater tuberosity and have multilineage differentiation ability. But the remnant degenerated with age and chronicity.

Remnant preservation with tensioning can improve the clinical outcome after anterior cruciate ligament reconstruction

BACKGROUND

Many studies exist about remnant preservation in anterior cruciate ligament (ACL) reconstruction. However, concern remains for development of a cyclops lesion during remnant preservation. To prevent this, a tensioning method has been suggested. Current study evaluated the clinical and radiologic results of remnant preservation in ACL reconstruction with tensioning compared to classical ACL reconstruction.

METHODS

From January 2016 to June 2017, ACL reconstruction patients who underwent magnetic resonance imaging (MRI) 2 years postoperatively were enrolled. For comparison, all participants were divided in two groups: remnant preservation with tensioning (group R) and controls (group C). Clinically, Hospital for Special Surgery (HSS), International Knee Documentation Committee (IKDC), Lysholm scores, and incidence of symptomatic cyclops lesions were evaluated. Radiologically, signal-to-noise quotient (SNQ) and size of the synovium on MRI as well as anterior instability in Telos stress radiographs were evaluated.

RESULTS

A total of 64 patients were enrolled (42 in group R and 22 in group C). The IKDC score in group R (70) was better than that in group C (62; p < 0.05). One patient in group R had a cyclops lesion with clinical symptoms and arthroscopic excision was recommended. Radiologically, the SNQ, synovium area, and anterior instability on Telos radiography showed no difference between the two groups.

CONCLUSION

Remnant preservation with tensioning is a good option for ACL reconstruction without the development of a cyclops lesion.

Adolescents show a lower healing rate of anterolateral ligament injury and a higher rotational laxity than adults after anterior cruciate ligament reconstruction

BACKGROUND

This study aimed to compare anterolateral ligament (ALL) injuries in anterior cruciate ligament (ACL) ruptures, as well as ALL healing and clinical outcomes following ACL reconstruction between adolescents and adults.

METHODS

This retrospective study involved 98 patients who underwent ACL reconstruction. They were divided into two groups according to age: group A (adolescents, 16-20 years of age; n = 49) and group B (adults, 21-45 years of age; n = 49). Subjective scores including ACL-Return to Sport after Injury (ACL-RSI) scale and objective tests were assessed. Follow up magnetic resonance imaging (MRI) and second-look arthroscopy was conducted at 1-year and 2-year follow up, respectively.

RESULTS

Good healing rate of ALL was higher in adults than in adolescents (P = 0.048). Graft tension and synovial coverage showed no significant differences between two groups. Group A showed a higher rate of high-grade pivot shift and a lower ACL-RSI at last follow up than group B (P = 0.126 and P = 0.016). Poor healing of ALL was significantly associated with lower ACL-RSI and failure to return to sports (P < 0.001 and P = 0.001). Re-rupture of the ACL graft was found in four (8.2%) and one (2.0%) of group A and B, respectively.

CONCLUSIONS

Adolescents showed a lower healing rate of ALL, a lower ACL-RSI, a higher rate of high-grade pivot shift than adults. Moreover, poor healing of ALL was significantly associated with a lower ACL-RSI and failure to return to sports. We suggest that adolescents need to pay more attention to the presence of ALL injury.

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.

Anterior cruciate ligament reconstruction with remnant preservation: current concepts

Anterior cruciate ligament (ACL) tears are a common knee injury, and anatomic ACL reconstruction (ACLR) is now the standard of care to restore knee stability. Nevertheless, re-tear rates exceeding 5% are commonly reported, with an even higher percentage of patients unable to achieve preinjury knee function. As the torn ACL remnant contains elements (eg, cells, blood vessels and mechanoreceptors) essential to ACL function, it has been hypothesised that ACLR with remnant preservation may improve graft remodelling, in turn more quickly and completely restoring ACL structure and function. In this Current Concepts review, we summarise the present understanding of ACLR with remnant preservation, which includes selective bundle reconstruction of partial (one-bundle) ACL tears and single- and double-bundle ACLR with minimal to partial debridement of the torn ACL stump. Reported benefits of remnant preservation include accelerated graft revascularisation and remodelling, improved proprioception, decreased bone tunnel enlargement, individualised anatomic bone tunnel placement, improved objective knee stability and early mechanical support (with selective bundle reconstruction) to healing tissues. However, clinical studies of ACLR with remnant preservation are heterogeneous in the description of remnant characteristics and surgical technique. Presently, there is insufficient evidence to support the superiority of ACLR with remnant preservation over the standard technique. Future studies should better describe the ACL tear pattern, remnant volume, remnant quality and surgical technique. Progress made in understanding and applying remnant preservation may inform, and be reciprocally guided by, ongoing research on ACL repair. The goal of research on ACLR with remnant preservation is not only to achieve anatomic structural restoration of the ACL but also to facilitate biologic healing and regeneration to ensure a more robust and functional graft.

Outcome Differences of Remnant- Preserving versus Non-Preserving Methods in Arthroscopic Anterior Cruciate Ligament Reconstruction: A Meta-analysis with Subgroup analysis

Purpose

To analyze differences in clinical outcomes of arthroscopic anterior cruciate ligament reconstruction between remnant-preserving and non-preserving methods.

Methods

International electronical databases PubMed, Embase, and the Cochrane central database from January 1966 to December 2017 were searched for randomized controlled trials (RCTs) and observational studies that compared differences of clinical outcomes of ACL reconstruction with and without remnant preservation. A meta-analysis of these studies was performed to compare clinical outcomes. Subgroup analyses were conducted to evaluate the role of methodological quality in primary meta-analysis estimates.

Results

Five RCTs and six observational studies were included in this meta-analysis and subgroup analysis. The remnant-preserving method in arthroscopic ACL reconstruction showed a statistically significant difference compared to the non-preserving method regarding arthrometric evaluation (side-to-side difference). Lachman test, Lysholm scores, and IKDC subjective scores showed statistically minor difference in meta-analysis, but showed no significant difference in subgroup analysis. Remained parameters including pivot shift test, IKDC grades, incidence of cyclops lesion showed no statistically differences in meta-analysis or subgroup analysis.

Conclusions

This meta-analysis with subgroup analysis showed that arthroscopic remnant-preserving ACL reconstruction provided statistically significant but limited clinical relevance in terms of arthrometric evaluation. Results of Lachman test, Lysholm scores, and IKDC subjective scores demonstrated statistically minor differences.

The Pivot Shift: Current Experimental Methodology and Clinical Utility for Anterior Cruciate Ligament Rupture and Associated Injury

PURPOSE OF REVIEW

The purpose of this manuscript is to (1) examine the history, techniques, and methodology behind quantitative pivot shift investigations to date and (2) review the current status of pivot shift research for its clinical utility for management of anterior cruciate ligament (ACL) rupture with associated injuries including the anterolateral complex (ALC).

RECENT FINDINGS

The pivot shift is a useful physical exam maneuver for diagnosis of rotatory instability related to ACL tear. Recent evidence suggests that the pivot shift is multifactorial and can be seen in the presence of ACL tear with concomitant injury to secondary stabilizers or with predisposing anatomical factors. The presence of a pivot shift post-operatively is associated with poorer outcomes after ACL reconstruction. Recent clinical and biomechanical investigations can help guide clinicians in utilizing pivot shift in diagnosis and surgical planning. Further research is needed to clarify optimal management of ALC in addition to ACL injury.

Effects of Remnant Tissue Preservation on Tunnel Enlargement After Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using the Hamstring Tendon

Background

The effects of remnant tissue preservation on tunnel enlargement after anatomic double-bundle anterior cruciate ligament (ACL) reconstruction have not yet been established.

Hypothesis

The preservation of ACL remnant tissue may significantly reduce the degree and incidence of tunnel enlargement after anatomic double-bundle ACL reconstruction, while the remnant-preserving procedure may not significantly increase the incidence of tunnel coalition after surgery.

Study Design

Cohort study; Level of evidence, 2.

Methods

A total of 79 patients underwent anatomic double-bundle ACL reconstruction. Based on the Crain classification of ACL remnant tissue, 40 patients underwent the remnant-preserving procedure (group P), and the remaining 39 patients underwent the remnant-resecting procedure (group R). There were no differences between the 2 groups concerning all background factors, including preoperative knee instability and intraoperative tunnel positions. All patients were examined using computed tomography and a standard physical examination at 2 weeks and 1 year after surgery.

Results

During surgery, the femoral and tibial anteromedial (AM) tunnel sizes in both groups averaged 6.6 and 6.5 mm, respectively. The femoral and tibial posterolateral (PL) tunnel sizes in both groups averaged 6 and 6 mm, respectively. There were no differences in the intraoperative tunnel positions and tunnel sizes between groups. Concerning the femoral AM tunnel, the degree of tunnel enlargement in the oblique coronal and oblique axial views in group P was significantly less than that in group R (P = .0068 and .0323, respectively). Regarding the femoral AM tunnel cross-sectional area, the degree and incidence of tunnel enlargement in group P were significantly less than those in group R (P = .0086 and .0278, respectively). There were no significant differences in tunnel coalition between groups. In each group, there were no significant relationships between tunnel enlargement and each clinical outcome.

Conclusion

Remnant preservation in anatomic double-bundle ACL reconstruction reduced enlargement of the femoral AM tunnel and did not increase the incidence of tunnel coalition. This is one of the advantages of remnant-preserving ACL reconstruction.

Comparison of Modified Transtibial and Outside-In Techniques in Anatomic Single-Bundle Anterior Cruciate Ligament Reconstruction

PURPOSE

To compare the bending angle of anterior cruciate ligament (ACL) graft at femoral tunnel, graft maturation, and tunnel positions and the clinical outcomes of the modified transtibial (mTT) and outside-in (OI) techniques.

METHODS

Patients who met the inclusion criteria were divided into the mTT group (n = 50) and the OI group (n = 50). Using 3-dimensional computed tomography (3-D CT), tunnel placement and femoral tunnel bending angle were analyzed. The 3.0-T magnetic resonance imaging (MRI) was used to assess the graft signal intensity (indicative of maturation) with signal/noise quotient (SNQ). Graft tension and synovialization were evaluated with second-look arthroscopy in all cases. Clinical and functional tests were completed at 36 months of follow-up.

RESULTS

When tunnel placements were analyzed using the quadrant method, no significant differences were found between the mTT group and the OI group. The femoral graft bending angle was reduced in the mTT group, and the total mean of SNQ values and mean SNQ values at the femoral intraosseous and proximal graft of the mTT group were significantly lower than in the OI group (P < .001), respectively. The femoral graft bending angle on the coronal and axial planes showed moderate-to-strong correlation with the SNQ values at the femoral intraosseous and proximal graft. Second-look arthroscopy revealed better synovialization in the mTT group than in the OI group (P = .040), with no significant difference in graft tension between the 2 groups (P = .328).

CONCLUSIONS

Anatomic tunnel placements did not vary between the mTT group and the OI group. However, the mTT group had more benefits in femoral graft bending angle and showed higher graft maturity and better synovial coverage than the OI group, although there were no significant differences in clinical outcomes. The acute femoral graft bending angle might negatively affect the maturation of proximal graft. LEVEL OF EVIDENCE: Level III, retrospective comparative study.

Remnant preservation technique versus standard technique for anterior cruciate ligament reconstruction: a meta-analysis of randomized controlled trials

Background

This meta-analysis was performed to compare the clinical outcomes of primary anterior cruciate ligament (ACL) reconstruction using the ACL remnant preservation technique versus the standard technique.

Methods

PubMed, Embase, and the Cochrane Library were searched through December 24, 2017, to identify randomized controlled studies that compared the use of the ACL remnant preservation technique versus the standard technique for primary ACL reconstruction. Statistical heterogeneity among the trials was evaluated with chi-square and I-square tests. A sensitivity analysis was conducted to explore sources of heterogeneity. Subgroup analysis was performed to identify potential differences according to type of ACL remnant tissue (remnant bundle or remnant fibers).

Results

Seven studies with a combined 412 patients (208 in the remnant preservation technique group and 204 in the standard technique group) were included in the meta-analysis. There was a significant difference between the groups in Lysholm score (mean difference (MD), 2.20; 95% confidence interval (CI), 0.95–3.45; P = 0.0006) and side-to-side difference (MD, − 0.71; 95% CI, − 0.87 to − 0.55; P < 0.01). There was no significant difference between the groups in subjective International Knee Documentation Committee (IKDC) score, complications, pivot shift test, Lachman test, or overall IKDC score. Subgroup analysis demonstrated that for primary ACL reconstruction with preservation of remnant fibers, the remnant preservation technique was superior to the standard technique based on Lysholm scores (P < 0.01) and side-to-side difference (P < 0.01).

Conclusions

Based on the current literature, using the remnant preservation technique showed a better clinical outcome than using the standard technique for patients undergoing primary ACL reconstruction with respect to Lysholm score and side-to-side difference. However, it remains unclear that there is a definite advantage to use the remnant preservation technique compared with the standard technique.

Electronic supplementary material

The online version of this article (10.1186/s13018-018-0937-4) contains supplementary material, which is available to authorized users.

Higher Gene Expression of Healing Factors in Anterior Cruciate Ligament Remnant in Acute Anterior Cruciate Ligament Tear

BACKGROUND

Anterior cruciate ligament (ACL) reconstruction with remnant preservation has been described and related to potential advantages. Literature is lacking regarding gene expression of potential factors related to ligament healing in the ACL remnant and its relation to time from injury.

HYPOTHESIS

The mRNA expression of ligament healing factors in the ACL remnant would be higher in acute tears (<3 months from injury) than in intermediate (3-12 months) and chronic (>12 months) injuries.

STUDY DESIGN

Controlled laboratory study.

METHODS

Gene expression of 21 genes related to ligament healing factors was analyzed in 46 ACL remnants biopsied during surgical reconstruction with quantitative real-time polymerase chain reaction technique. Specimens were divided into 3 groups according to time from injury: acute (<3 months from injury; n = 19), intermediate (3-12 months; n = 12), and chronic (>12 months; n = 15). Histological and immunohistochemical evaluation was performed by analysis of hematoxylin and eosin, CD-34, and S-100 staining.

RESULTS

Expression of COL1A1, COL1A2, COL3A1, COL5A1, COL5A2, COL12A1, LOX, PLOD1, and TNC genes in ACL remnant was greater in acute compared with chronic injuries. COL1A1, COL5A1, COL12A1, and TNC genes were also expressed more in the acute group compared with the intermediate group. Furthermore, expression of the genes COL1A1 and COL5A2 was significantly higher in female than in male patients. No difference in the number of blood vessels and mechanoreceptors among groups was observed in the microscopic evaluation.

CONCLUSION

The present study demonstrates that expression of COL1A1, COL1A2, COL3A1, COL5A1, COL5A2, COL12A1, LOX, PLOD1, and TNC genes in ACL remnant is greater in acute (<3 months from injury) compared with chronic (>12 months) injuries. Furthermore, COL1A1, COL5A1, COL12A1, and TNC genes were expressed more in the acute group compared with the intermediate group (3-12 months from injury).

CLINICAL RELEVANCE

ACL reconstructions with remnant preservation should be performed in patients with acute injuries, as in these cases the ACL remnant may present the greatest healing potential.