Impact of chronicity of injury on the proportion of mesenchymal stromal cells derived from anterior cruciate ligaments

Effects of Preserving Anatomically Positioned and Adequate Remnant ACL Tissue in Double-Bundle ACL Reconstruction

Background

The advantages of remnant tissue preservation in anterior cruciate ligament (ACL) reconstruction (ACLR) remain controversial.

Hypothesis

It was hypothesized that a large amount of remnant tissue, especially if anatomically positioned, would improve patient-reported outcomes and second-look graft appearance after preserved double-bundle ACLR (DB-ACLR).

Study Design

Cohort study; Level of evidence, 3.

Methods

This retrospective study included 89 consecutive patients who underwent unilateral remnant-preserving DB-ACLR using 2 hamstring tendon autografts. The authors categorized the arthroscopic findings into 3 groups according to the location and volume of the ACL remnant tissue in the femoral notch: (1) anatomical attachment (group AA; n = 34); (2) nonanatomical attachment (group NA; n = 33); and (3) no remnant (group NR; n = 22). Based on second-look arthroscopy, the reconstructed graft was graded as excellent, fair, or poor. Patient-reported outcomes were evaluated at 2 years after surgery using the Knee injury and Osteoarthritis Outcome Score (KOOS) and the Japanese Anterior Cruciate Ligament Questionnaire-25 (JACL-25).

Results

The AA and NA groups had a significantly shorter time from injury to surgery compared with the NR group (P = .0165). Considering the second-look arthroscopic findings, the authors found a significant difference in synovial coverage of the grafts between the 3 groups (P = .0018). There were no significant differences in the overall KOOS and JACL-25 score among the 3 groups; however, the KOOS-Sport and Recreation and KOOS-Quality of Life subscale scores were significantly higher in the AA group compared with the NA and NR groups (P = .0014 and .0039, respectively). The JACL-25 score for middle- to high-speed flexion and extension was significantly better in the AA group versus the NR group (P = .0261).

Conclusion

This study showed that preserving anatomically positioned and adequate remnant tissue during DB-ACLR improved second-look graft appearance and KOOS-Sport and Recreation and KOOS-Quality of Life scores.

Midterm Results of Arthroscopy-Assisted "Tent Form" Triangular Fibrocartilage Complex Repair With Dorsal Distal Radioulnar Joint Capsule Imbrication for Posttraumatic Chronic Distal Radioulnar Joint Instability

PURPOSE

To evaluate the outcomes of "tent form" triangular fibrocartilage complex (TFCC) repair combined with dorsal distal radioulnar joint (DRUJ) capsule imbrication for posttraumatic chronic DRUJ instability.

METHODS

All patients treated with arthroscopic "tent form" TFCC repair and DRUJ capsule imbrication from 2016 to 2019 were retrospectively reviewed. The inclusion criteria were symptomatic chronic DRUJ instability for >6 months and dorsal DRUJ subluxation on magnetic resonance imaging. The Disabilities of the Arm, Shoulder, and Hand score, Patient-Rated Wrist Evaluation, grip strength, Modified Mayo Wrist Score, range of motion, and distal radioulnar joint stability were assessed for a minimum of 2 years postoperatively.

RESULTS

Thirty-eight patients were included in the final analysis. The average follow-up duration was 35.6 months (range, 24-48 months). The 24-month postoperative grip strengths and 3-dimensional motions of wrist were not significantly different from that of the nonoperated wrist. Compared with their preoperative status, Disabilities of the Arm, Shoulder, and Hand score, Patient-Rated Wrist Evaluation, and Modified Mayo Wrist Score indicated the significant improvement with P values of .001, .001, and .002, respectively.

CONCLUSIONS

In chronic DRUJ instability with a loosening dorsal capsule, "tent form" TFCC transcapsular repair combined with DRUJ capsule imbrication restored the integrity of TFCC and dorsal DRUJ capsule and achieved a promising outcome. We recommend this procedure as an option of treatment for patients with posttraumatic chronic DRUJ instability.

LEVEL OF EVIDENCE

IV, case series.

Functional Outcomes Are Similar After Early and Late Arthroscopic One-Tunnel Transosseous Repair of Triangular Fibrocartilage Complex Foveal Tears

PURPOSE

To compare outcomes at different time periods following arthroscopic triangular fibrocartilage complex (TFCC) transosseous foveal repair within 6 months, between 6 and 12 months, and more than 12 months from injury.

METHODS

Consecutive patients treated with arthroscopic TFCC foveal repair using the uniform one-tunnel transosseous suture technique by a surgeon from 2014 to 2017 were retrospectively reviewed. The patients were assigned to 1 of 3 groups according to time between injury and surgery. Pain visual analog scale (VAS); grip strength; modified Mayo wrist score (MMWS); Quick disabilities of the arm, shoulder, and hand (QuickDASH) score; and distal radioulnar joint stability were assessed at minimum 2 years postoperatively, along with minimal clinically important difference, and overall patient satisfaction.

RESULTS

This study cohort consisted of 80 patients: group A (<6 months, n = 38), group B (6-12 months, n = 20), and group C (>12 months, n = 22). No differences were found among groups in VAS, grip strength, and MMWS and QuickDASH. Overall, patients exhibited significant functional improvement at 2 years (VAS: 3-0, P < .001; grip strength: 77.1%-95.6%, P < .001; MMWS: 65-90, P < .001, QuickDASH: 20.5-4.5, P < .001). Median changes in outcome variables and the proportion of patients achieving minimal clinically important difference for the QuickDASH were similar among groups. Seventy-eight patients (97%) achieved distal radioulnar joint stability, and 70 patients (87%) were satisfied with treatment.

CONCLUSIONS

Although this current study has insufficient statistical power, the available data suggest that patients with a TFCC foveal tear who underwent arthroscopic transosseous repair surgery more than 12 months after injury could expect to experience similar functional improvement compared with patients who underwent surgery within 6 months or between 6 and 12 months following injury.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Is Remnant Preservation in Anterior Cruciate Ligament Reconstruction Superior to the Standard Technique? A Systematic Review and Meta-Analysis

Purpose

This is a systematic review and meta-analysis of current evidence that aims at comparing the clinical outcomes of remnant-preserving anterior cruciate ligament reconstruction (ACLR) and standard ACLR.

Methods

A systematic review of randomized controlled studies and cohort studies comparing remnant-preserving ACLR with standard ACLR with a minimum level of evidence of II was performed. Studies were included by strict inclusion and exclusion criteria. Extracted data were summarized as preoperative conditions, postoperative clinical outcomes, and postoperative complications. When feasible, meta-analysis was performed with RevMan5.3 software. Study methodological quality was evaluated with the modified Coleman methodology score (CMS).

Results

Eleven studies (n = 466 remnant-preserving and n = 536 standard) met the inclusion criteria. The mean modified CMS for all included studies was 85.8 (range: 77–92 on a 100-point scale). In total, 466 patients underwent remnant-preserving ACLR by 3 different procedures: standard ACLR plus tibial remnant tensioning (n = 283), selective-bundle augmentation (n = 49), and standard ACLR plus tibial remnant sparing (n = 134). Remnant-preserving ACLR provided a superior outcome of postoperative knee anterior stability (WMD = −0.42, 95% CI, −0.66, −0.17; P < 0.01) and Lysholm score (WMD = 2.01, 95% CI, 0.53 to 3.50; P < 0.01). There was no significant difference between the two groups with respect to second-look arthroscopy (OR = 1.38, 95% CI, 0.53, 3.62; P=0.51), complications (OR = 1.24 95% CI, 0.76, 2.02; P=0.39), International Knee Documentation Committee (IKDC) subject scores, IKDC grades, Lachman test, and pivot-shift test.

Summary/conclusion

Remnant-preserving ACLR promotes similar graft synovial coverage and revascularization to standard ACLR. Equivalent or superior postoperative knee stability and clinical scores were observed for remnant-preserving ACLR compared with standard ACLR. No significant difference in the total complication rate between the groups was evident.

Impact of Surgical Timing on Clinical Outcomes in Anatomic Double-Bundle Anterior Cruciate Ligament Reconstruction Using Hamstring Tendon Autografts

Background:

To date, no studies have analyzed the influence on clinical outcomes of the interval between an anterior cruciate ligament (ACL) injury and double-bundle (DB) reconstruction with hamstring tendon autografts.

Hypotheses:

(1) Performing ACL reconstruction sooner after an injury will reduce postoperative anterior and rotatory knee instability, (2) postoperative range of knee motion or functional results will not be affected by different intervals between injury and surgery, and (3) preoperative isokinetic peak torque of the quadriceps and hamstring muscles will be lower in patients undergoing surgery earlier, while postoperative muscle strength will not be affected by surgery timing.

Study Design:

Cohort study; Level of evidence, 3.

Methods:

This study was conducted on a total of 171 patients who had undergone anatomic DB ACL reconstruction with hamstring tendon autografts. The patients were divided into 3 groups based on the time to surgery: (1) ≤1 month after the injury (group E; n = 25), (2) between 1 and 3 months after the injury (group M; n = 72), and (3) >3 months after the injury (group D; n = 74). Patients were assessed for a minimum of 2 years after surgery.

Results:

Concerning postoperative anterior laxity, 1-way analysis of variance demonstrated a significant difference (P = .0274) among the 3 groups. Anterior laxity was significantly less in group E than in group D (P = .0206). Spearman rank correlation analysis showed a significant correlation (ρ = 0.200; P = .0327) between anterior knee laxity and time to surgery. Also, a significant correlation (P = .0461) was found between the degree of the pivot-shift phenomenon and time to surgery. There were no significant differences in loss of knee extension or flexion among the 3 groups, nor were there any differences in the Lysholm knee score or International Knee Documentation Committee grade. Postoperatively, there were no significant differences in peak torque of the quadriceps or hamstring muscles among the 3 groups.

Conclusion:

Early DB reconstruction led to significantly less anterior laxity compared with delayed reconstruction. There were no significant differences in postoperative range of knee motion or functional results among the 3 time intervals between injury and surgery in this study.

Biomechanical Comparison of Anatomic and Extra-Anatomic Reconstruction Techniques Using Local Grafts for Chronic Instability of the Acromioclavicular Joint

BACKGROUND

Anatomic reconstruction techniques are increasingly used to address cases of acromioclavicular (AC) joint chronic instability. These usually involve an additional surgical site for autograft harvesting or an allograft.

PURPOSE

To describe a triple-bundle (TB) anatomic reconstruction using on-site autografts, the semiconjoint tendon (SCT) and the coracoacromial ligament (CAL), and compare its primary stability to the native AC joint ligamentous complex and to a modified Weaver-Dunn (WD) reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Intact AC joints of 12 paired cadaveric shoulders were tested for anterior, posterior, and superior translations under cyclic loading with a servo-hydraulic testing system. One shoulder from each pair was randomly assigned to the TB group, where 2 SCT strips were used to reconstruct the coracoclavicular ligaments while the distal end of the CAL was transferred to the distal extremity of the clavicle to reconstruct the AC ligaments; the other shoulder received a modified WD reconstruction. After reconstruction, the same translational testing was performed, with an additional load-to-failure test in the superior direction.

RESULTS

In both the TB and the WD groups, no significant differences were found before and after reconstruction in terms of joint displacements after cyclic loading, in all 3 directions. Compared with the WD reconstruction, the TB repair resulted in significantly lower displacements in both the anterior (ie, 2.59 ± 1.08 mm, P = .011) and posterior (ie, 10.17 ± 6.24 mm, P = .014) directions, but not in the superior direction. No significant differences were observed between the 2 reconstructions during the load-to-failure testing, except for the displacement to failure, which was significantly smaller (ie, 5.34 ± 2.97 mm) in the WD group ( P = .037).

CONCLUSION

Anterior, posterior, and superior displacements after an anatomic reconstruction of the AC joint complex using the SCT and CAL as graft material were similar to those of native AC joints and significantly smaller in the axial plane than those of AC joints after a WD repair.

CLINICAL RELEVANCE

An anatomic reconstruction is achievable using the CAL and the SCT as on-site graft materials, providing satisfactory initial stability and thereby allowing earlier mobilization.

The Influence of Ruptured Scar Pattern on the Healing Potential of Anterior Cruciate Ligament Remnant Cells

BACKGROUND

Vascular CD34+ cells in anterior cruciate ligament (ACL) tissues have a potential for high proliferation and multilineage differentiation, which can accelerate tendon-bone healing after ACL reconstruction. To predict outcomes of ACL reconstruction with remnant preservation or ruptured tissue incorporation, patient characteristics should be considered. However, the influence of ACL remnant morphologic pattern on healing potential remains unknown.

HYPOTHESIS

The healing potential of ACL remnants could differ among their morphologic patterns.

STUDY DESIGN

Descriptive laboratory study.

METHODS

ACL remnant tissues were harvested from patients aged <35 years who received primary ACL reconstruction within 3 months after injury. The tissues were evaluated according to the Crain classification (4 patterns). The patterns were divided into 2 groups: the reattachment group (Crain I-III) and the nonreattachment group (Crain IV). ACL remnant cells were characterized via fluorescence-activated cell sorting. The potential for proliferation and multilineage differentiation was assessed and compared between the groups.

RESULTS

The ratio of CD34+ cells was significantly higher in the nonreattachment group than in the reattachment group. In early passages, the nonreattachment group had a significantly higher expansion potential than the reattachment group. In the evaluation of osteogenic and endothelial differentiation potential, the nonreattachment group showed a higher potential in immunohistochemical/histochemical staining and quantitative real-time polymerase chain reaction analysis as compared with the reattachment group.

CONCLUSION

In the subacute phase, ACL remnant tissue of the nonreattachment group possibly has a higher healing potential than that of the reattachment group.

CLINICAL RELEVANCE

If healing potential differs among the morphologic patterns of ACL remnants, surgeons may expect the healing potential when preserving remnants.

Triple-bundle anatomical reconstruction using the coracoacromial ligament and the short head of biceps tendon to stabilize chronic acromioclavicular joint dislocations: A cadaver feasibility study

INTRODUCTION

In cases of chronic acromioclavicular joint separation, the biomechanical properties of anatomical reconstructions are closer to the native configuration than the Weaver-Dunn procedure. Consequently, the radiological and clinical outcomes are better. However, an additional incision is needed to harvest the graft, which increases the procedure's morbidity.

HYPOTHESIS

Triple-bundle reconstruction can be performed with the coracoacromial ligament (CAL) and the semi conjoined tendon (SCT).

MATERIAL AND METHODS

Bilateral dissection was performed on the upper limb of six fresh-frozen cadavers. Measurements useful to the procedure were taken on one limb, specifically the minimum graft length needed and the available length. The surgical procedure was performed on the other limb. The proximally based SCT was passed through the base of the coracoid process, then divided into two strips tightened from the superior aspect of the coracoid process to the clavicular insertion points of the conoid and trapezoid ligaments. The CAL was detached from the coracoid process and then secured in the medullary canal of the clavicle, after its lateral one-quarter was resected (i.e., 10mm).

RESULTS

The mean length of the SCT was 101.7±7.6mm (95.1-114.5) and the mean length of the CAL was 35.3±4.7mm (28.7-42.5). The SCT length needed for this reconstruction was 58±4.3mm (51.5-62) medially and 60.3±4.6mm (54.3-66.3) laterally. The procedure was feasible in all six cadavers with an average excess length of 39.9±5.7mm (32.2-47) for the conoid bundle, 37.6±5mm (31-45.1) for the trapezoid ligament and 6±2.7mm (3-9.5) for the CAL.

DISCUSSION

Triple-bundle anatomical reconstruction using the SCT and CAL is feasible. However, the strength of this construct must be evaluated biomechanically before it can be used clinically.

LEVEL OF EVIDENCE

Not applicable - cadaver study.

Influence of the Injury-to-Surgery Interval on the Healing Potential of Human Anterior Cruciate Ligament-Derived Cells

BACKGROUND

Vascular CD34+ cells in anterior cruciate ligament (ACL) tissue have the potential for high proliferation and multilineage differentiation that can accelerate tendon-bone healing. While patient characteristics, such as age, can affect tendon-bone healing, the influence of elapsed time after injury on the healing process is unclear.

HYPOTHESIS

Cells obtained during the early phase after injury will exhibit a greater tendon-bone healing potential compared with chronic phase counterparts when applied to an immunodeficient rat model of ACL reconstruction.

STUDY DESIGN

Controlled laboratory study.

METHODS

Adult human ACL-ruptured tissue was harvested from patients undergoing arthroscopic primary ACL reconstruction and classified into 2 groups based on the time elapsed between injury and surgery: (1) early group (≤3 months from injury) and (2) chronic group (>3 months from injury). In addition, 76 ten-week-old female immunodeficient rats underwent ACL reconstruction, followed by intracapsular administration of one of the following: (1) ACL-derived cells from the early group (n = 5), (2) ACL-derived cells from the chronic group (n = 5), or (3) phosphate-buffered saline (PBS) only (n = 5). During the 8 weeks after surgery, histological (weeks 2, 4, 8), immunohistochemical (week 2), radiographic (weeks 0, 2, 4, 8), and biomechanical (week 8) analyses were performed to evaluate tendon-bone healing.

RESULTS

In the early group, the histological evaluation showed early healing, induction of endochondral ossification-like integration, and mature bone ingrowth. Micro-computed tomography showed that the tibial bone tunnels at week 4 and week 8 were significantly reduced in the early group compared with those in the chronic group and PBS group ( P < .05). Moreover, biomechanical tensile strength was significantly greater in the early group than in the other groups ( P < .05). An accelerated healing potential in the early group was further demonstrated by the enhancement of intrinsic angiogenesis/osteogenesis and human-derived vasculogenesis/osteogenesis.

CONCLUSION

Compared with human ACL-derived cells obtained during the chronic phase, cells obtained during the early phase after injury have a greater tendon-bone healing potential when used in an immunodeficient rat model of ACL reconstruction.

CLINICAL RELEVANCE

During ACL reconstruction surgery, transplanting ACL remnant tissue in the early phase after injury could accelerate and enhance tendon-bone healing.

Changes in Transcriptome-Wide Gene Expression of Anterior Cruciate Ligament Tears Based on Time From Injury

BACKGROUND

Anterior cruciate ligament (ACL) tears are a common injury. The healing potential of the injured ACL is poorly understood and is considered limited. Therefore, most ACL tears that are treated surgically undergo reconstruction rather than repair. However, there has been renewed interest recently in repairing ACL tears despite unanswered questions regarding the healing capacity of the ACL.

HYPOTHESIS

Gene expression in the injured ACL varies with time from injury.

STUDY DESIGN

Descriptive laboratory study.

METHODS

Transcriptome-wide expression profiles of 24 human ACL remnants recovered at the time of surgical reconstruction were analyzed using the Agilent human 8x60K microarray platform. Gene ontology was performed on differentially expressed transcripts based on time from injury (acute, <3 months; intermediate, 3-12 months; chronic, >12 months). A subset of transcripts with large fold changes in expression between any 2 categories was validated via microfluidic digital polymerase chain reaction.

RESULTS

Numerous transcripts representing important biological processes were differentially expressed by time from injury. The most significant changes were noted between the acute and chronic groups. Expression of several extracellular matrix genes- namely, POSTN, COL5A1, COL1A1, and COL12A1-was lower in the chronic tears compared with acute and intermediate tears. In acute tears, processes representing angiogenesis and stem cell differentiation were affected. In intermediate tears, processes representing stem cell proliferation concomitant with cellular component organization/cellular localization were altered. In ACL tears more than 12 months out from injury, processes denoting myosin filament organization, cellular component organization/cell localization, and extracellular matrix organization were affected.

CONCLUSION

These findings are consistent with initial repair activity in the injured ACL, which declines with time from injury. Individual genes identified in this study, such as periostin, deserve further investigation into their role in tissue repair.

CLINICAL RELEVANCE

The decreased healing capacity of ACL tears over time is relevant to the development of effective techniques for repairing ACL tears and may have some significance for ACL reconstruction techniques as well. The potential for healing appears to be greatest in acute ACL tears, suggesting this window should be the focus of research for ACL repair.

Anterior cruciate ligament - updating article

This updating article on the anterior cruciate ligament (ACL) has the aim of addressing some of the most interesting current topics in this field. Within this stratified approach, it contains the following sections: ACL remnant; anterolateral ligament and combined intra and extra-articular reconstruction; fixation devices; and ACL femoral tunnel creation techniques.

Arthroscopic Stabilization of Chronic Acromioclavicular Joint Dislocations: Triple- Versus Single-Bundle Reconstruction

BACKGROUND

Arthroscopically assisted single-bundle (SB) or double-bundle coracoclavicular (CC) ligament reconstruction using autologous tendon grafts has been reported to provide acromioclavicular (AC) joint (ACJ) stability in chronic instability cases. Recently, additional AC ligament reconstruction to provide triple-bundle (TB) stabilization has been introduced but lacks a comparison of clinical and radiological outcomes.

HYPOTHESIS

Arthroscopically assisted anatomic TB CC and AC reconstruction yields superior clinical and radiological results when compared with nonanatomic SB CC reconstruction.

STUDY DESIGN

Cohort study; Level of evidence, 2.

METHODS

Twenty-six patients (mean [±SD] age, 46.9 ± 12.8 years) suffering from chronic high-grade ACJ instability underwent ACJ stabilization using autologous hamstring grafts. Twelve patients underwent combined anatomic TB CC and AC reconstruction using a semitendinosus tendon with clavicular interference screw fixation (TB group), and 14 underwent isolated SB CC reconstruction using the AC GraftRope system with a gracilis tendon (SB group). After a minimum follow-up of 2 years (mean, 29.0 ± 7.4 months), patients were evaluated radiologically and clinically using the Constant, American Shoulder and Elbow Surgeons (ASES), Taft, and Acromioclavicular Joint Instability Score (ACJI) outcome measures.

RESULTS

The mean Constant score increased significantly in both groups, from 71.6 preoperatively to 88.8 postoperatively in the TB group and from 67.8 to 82.6 in the SB group (P ≤ .009). No intergroup difference was found regarding the final Constant or ASES scores. Regarding the ACJ-specific scores, the final outcomes were significantly different: 10.9 (TB group) versus 9.0 (SB group) for the mean Taft score (P = .018) and 84.7 versus 58.4, respectively, for the mean ACJI score (P = .0001). No significant radiological difference was found regarding the mean CC distance (10.7 mm [TB group] vs 13.1 mm [SB group]). The TB group showed superior horizontal ACJ stability (P = .011), which was associated with a better clinical outcome according to the ACJI and Taft scores. In the SB group, the rate of ACJ instability recurrence was higher (21% vs 8% [TB group]).

CONCLUSION

Combined arthroscopically assisted anatomic TB CC and AC ligament reconstruction using an autologous semitendinosus tendon graft provides superior clinical and radiological results compared with isolated nonanatomic SB CC ligament reconstruction using the AC GraftRope system. In particular, the TB technique can better restore horizontal ACJ stability, which is associated with superior ACJ-specific outcome scores.

Anterior cruciate ligament remnant tissue harvested within 3-months after injury predicts higher healing potential

Background

No study has examined the possible factors associated with different characteristics of stem-like cells derived from anterior cruciate ligament (ACL) remnants. And the purpose of the study is to elucidate whether demographic factors are associated with healing potential of stem-like cells derived from the ACL remnants tissue.

Methods

Thirty-six ACL remnants were harvested from patients who received primary arthroscopic ACL reconstruction. Interval from injury to surgery, age, sex, and combined meniscal or chondral injuries were analyzed. Cells were isolated from remnant tissues and their healing potential was evaluated by: 1) characterization of surface markers (CD34, CD44, CD45, CD146, CD29, and Stro-1), 2) cell expansion, 3) osteogenic differentiation, and 4) endothelial differentiation. Finally, using multivariable logistic regression to evaluate the relation between demographic factors and healing potential parameters. Adjusted odds ratios (OR) were calculated, and the significant difference was set at p < 0.05.

Results

ACL remnant tissue harvested less than 90 days after injury predicted higher fractions of stem-like cells [CD34+ (OR = 6.043, p = 0.025), CD44 + (OR = 8.440, p = 0.011), CD45+ (OR = 16.144, p = 0.015), and CD146+ (OR = 9.246, p = 0.015)] and higher expansion potential (passage 3: OR = 9.755, p = 0.034; passage 10: OR = 33.245, p = 0.003). Regarding osteogenic differentiation, higher gene expression of Osteocalcin (OR = 22.579, p = 0.009), Alkaline phosphatase (OR = 6.527, p = 0.022), and Runt-related transcription factor 2 (OR = 5.247, p = 0.047) can also be predicted. Younger age predicted higher CD34+ levels (20 ≤ age <30 years, OR = 2.020, p = 0.027) and higher expansion potential at passage 10 (10 ≤ age <20 years, OR = 25.141, p = 0.026). There was no significant relation found between meniscal or chondral injuries and ACL healing potential.

Conclusion

Our results indicated that the ACL remnant tissue harvested within 3-months after injury yields higher healing potential, suggesting early surgical intervention may achieve better clinical results.

Updates in biological therapies for knee injuries: anterior cruciate ligament

There have been many advances in anterior cruciate ligament reconstruction (ACLR) techniques incorporating biological treatment. The aim of this review is to discuss the recent contributions that may enlighten our understanding of biological therapies for anterior cruciate ligament (ACL) injuries and improve management decisions involving these enhancement options. Three main biological procedures will be analyzed: bio-enhanced ACL repair, bio-enhanced ACLR scrutinized under the four basic principles of tissue engineering (scaffolds, cell sources, growth factors/cytokines including platelet-rich plasma, and mechanical stimuli), and remnant-preserving ACLR. There is controversial information regarding remnant-preserving ACLR, since different procedures are grouped under the same designation. A new definition for remnant-preserving ACLR surgery is proposed, dividing it into its three major procedures (selective bundle augmentation, augmentation, and nonfunctional remnant preservation); also, an ACL lesion pattern classification and a treatment algorithm, which will hopefully standardize these terms and procedures for future studies, are presented.