The science of reconstruction of the anterior cruciate ligament

Increased knee laxity with hamstring tendon autograft compared to patellar tendon autograft: a cohort study of 5462 patients with primary anterior cruciate ligament reconstruction

PURPOSE

To compare anterior knee laxity and patient-reported outcome measures (PROMs) between anterior cruciate ligament reconstruction (ACLR) performed with bone-patellar tendon-bone (BPTB) and hamstring tendon (HT) autografts and, moreover, to study any correlation between postoperative anterior knee laxity and PROMs.

METHODS

Patients who underwent primary ACLR at Capio Artro Clinic, Stockholm, Sweden, from January 2000 to October 2015, were identified in our local database. Instrumented laxity measurements and PROMs were reviewed. The KT-1000 arthrometer, with an anterior tibial load of 134-N, was used to evaluate knee laxity preoperatively and at the 6-month follow-up. The Lysholm score was collected preoperatively and at 6 months postoperatively. The Knee injury and Osteoarthritis Outcome Score (KOOS) was collected preoperatively and at the 1-year follow-up.

RESULTS

A total of 5462 primary ACLRs, 692 BPTBs and 4770 HT autografts were included in the study. All the patients showed a significant reduction in knee laxity from preoperatively to postoperatively (BPTB group: from 3.8 ± 2.6 to 1.2 ± 2.1 mm; HT group: from 3.6 ± 3.1 to 1.8 ± 2.2 mm; P < 0.001 for both). The HT group showed a significantly increased postoperative knee laxity compared with the BPTB group (1.8 ± 2.2 vs 1.2 ± 2.1 mm; P < 0.001). The mean anterior tibial translation (ATT) reduction from preoperative to postoperative was significantly larger for the BPTB graft compared with the HT graft (2.7 ± 2.2 vs 1.7 ± 2.6 mm; P < 0.001). A significantly higher rate of "surgical failures", defined as a postoperative side-to-side (STS) difference > 5 mm, was found in the HT group compared with the BPTB group at follow-up (4.3 vs 2.4%; P < 0.001). A significantly larger improvement was found in the HT group compared with the BPTB group for the KOOS Pain (9.5 vs 8.0; P = 0.02), Activities of Daily Living (7.2 vs 5.7; P = 0.006), Sports (24.2 vs 15.3; P < 0.001) and Quality of Life (25.8 vs 22.1; P = 0.001) subscales. No significant difference regarding the mean improvement in the Lysholm knee score was found between the two grafts (BPTB group: 14.5, HT group: 14.0; n.s.). No correlation between postoperative anterior knee laxity and PROMs was found in either graft group.

CONCLUSION

Primary ACLR performed with HT autograft resulted in greater postoperative anterior knee laxity and significantly more surgical failures (STS > 5 mm) compared with BPTB autograft. The BPTB autograft showed a larger anterior knee laxity reduction (ATT reduction) in conjunction with primary ACLR. The HT autograft led to a significantly larger improvement in four of five KOOS subscales from preoperatively to the 1-year follow-up, compared with BPTB autograft. There was no association between postoperative anterior knee laxity and PROMs for either graft. The findings of the present study provide clinicians with valuable information regarding differences in knee laxity and subjective knee function between BPTB and HT autograft after primary ACLR. The use of BPTB autograft should be considered for patients with high knee stability demands.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

Arthroscopic ACL reconstruction using fixed suspensory device versus adjustable suspensory device for femoral side graft fixation: What are the outcomes?

INTRODUCTION

The aim of the study was to evaluate the outcomes of Arthroscopic ACL Reconstruction using Fixed suspensory device and Adjustable suspensory device for femoral side graft fixation.

MATERIAL AND METHODS

We conducted a prospective study of sixty two patients with ACL deficient knees treated with arthroscopic ACL reconstruction. Consecutively patients were operated with fixed loop and adjustable loop suspensory devices for femoral side graft fixation and no randomization was done.

RESULTS

Functional assessment was performed with VAS score, IKDC score and Lyshom score before and after surgery with ACL reconstruction. The postoperative Lyshom score in fixed loop group and adjustable loop group was 94.23 and 94.32 respectively. The IKDC score in fixed group and adjustable group was 92.03 and 92.16 respectively. VAS in fixed loop group improved from score of 5-3, while in adjustable loop group from score of 4-3. There was significant improvement in stability of knee assessed by Lachman's test, anterior drawer test, and Pivot shiff's test and both methods of fixation provide stability to knee. The complications included; restriction of terminal flexion in 12 patients: 6 in each group. There was no implant breakage in both groups.

CONCLUSION

Arthroscopic ACL reconstruction using fixed loop and adjustable loop suspensory devices are equally effective fixation methods.

Effect of stochastic resonance on proprioception and kinesthesia in anterior cruciate ligament reconstructed patients

Low amplitude mechanical noise vibration has been shown to improve somatosensory acuity in various clinical groups with comparable deficiencies through a phenomenon known as Stochastic Resonance (SR). This technology showed promising outcomes in improving somatosensory acuity in other clinical patients (e.g., Parkinson's disease and osteoarthritis). Some degree of chronic somatosensory deficiency in the knee has been reported following anterior cruciate ligament (ACL) reconstruction surgery. In this study, the effect of the SR phenomenon on improving knee somatosensory acuity (proprioception and kinesthesia) in female ACL reconstructed (ACLR) participants (n = 19) was tested at three months post-surgery, and the results were compared to healthy controls (n = 28). Proprioception was quantified by the measure of joint position sense (JPS) and kinesthesia with the threshold to detection of passive movement (TDPM). The results based on the statistical analysis demonstrated an overall difference between the somatosensory acuity in the ACLR limb compared to healthy controls (p = 0.007). A larger TDPM was observed in the ACLR limb compared to the healthy controls (p = 0.002). However, the JPS between the ACLR and healthy limbs were not statistically significantly different (p = 0.365). SR significantly improved JPS (p = 0.006) while the effect was more pronounced in the ACLR cohort. The effect on the TDPM did not reach statistical significance (p = 0.681) in either group. In conclusion, deficient kinesthesia in the ACLR limb was observed at three months post-surgery. Also, the positive effects of SR on somatosensory acuity in the ACL reconstructed group warrant further investigation into the use of this phenomenon to improve proprioception in ACLR and healthy groups.

Changes in patellar height due to bone-tendon-bone graft

PURPOSE

Complications related to anterior cruciate ligament (ACL) graft are common. Change in height, especially patella baja, can be a cause of anterior knee pain. Several studies have related ACL reconstruction with bone-tendon-bone graft to patella baja.

METHODS

Forty-three patients with ACL reconstruction using a with bone-tendon-bone graft were included in this study. All patients underwent the same surgery, with closure of the paratenon of the patellar tendon. A radiological study was performed before surgery and 2 years after surgery. The Insall-Salvati index, axial view and patellar tilt were analyzed in all patients. The healthy contralateral knees were used as the control group.

RESULTS

No significant differences were observed from the preoperative measurements or at the 2-year follow-up.

CONCLUSIONS

The use of patellar tendon with closure of the paratenon in ACL reconstruction was not shown to modify patellar height within the radiological follow-up of two years.

Validation of a Composite Test for Assessment of Readiness for Return to Sports After Anterior Cruciate Ligament Reconstruction: The K-STARTS Test

Background:

There is limited information on the appropriate timing of return to sports after anterior cruciate ligament (ACL) reconstruction. A composite test was developed to assess the athlete’s ability to return to sports after ACL reconstruction: the Knee Santy Athletic Return To Sport (K-STARTS) test.

Hypothesis:

The K-STARTS test meets validation criteria for an outcome score assessing readiness for return to sports after ACL reconstruction.

Study Design:

Diagnostic study.

Level of Evidence:

Level 3.

Methods:

A prospective comparative study identified 410 participants: 371 participants who had undergone ACL reconstruction and a control group of 39 healthy participants. The K-STARTS score is calculated as the sum of 7 tests (8 components), for a maximal value of 21 points. Construct validity, internal consistency, discriminant validity, and sensitivity to change were used to validate this new test.

Results:

The K-STARTS assessment showed a high completion rate (100%), high reproducibility (intraclass correlation coefficient, 0.87; coefficient of variation, 7.8%), and high sensitivity to change. There was moderate correlation with the ACL Return to Sports after Injury scale (ACL-RSI) and hop tests. There were no ceiling or floor effects. There was a significant difference between K-STARTS scores assessed at 6 and 8 months postoperatively (11.2 ± 2.7 vs 17.1 ± 3.2; P < 0.001). The K-STARTS score in the control group was significantly higher than that in the ACL reconstruction group (17.3 ± 2.1 and 13.7 ± 3.8, respectively; P < 0.001).

Conclusion:

The K-STARTS test is an objective outcome measure for functional improvement after ACL reconstruction.

Clinical Relevance:

It is important for the clinician to determine when return to sports is optimal after ACL reconstruction to reduce the current high risk of reinjury.

Associations Between Slower Walking Speed and T1ρ Magnetic Resonance Imaging of Femoral Cartilage Following Anterior Cruciate Ligament Reconstruction

OBJECTIVE

To determine whether walking speed, collected at 6 and 12 months following anterior cruciate ligament reconstruction (ACLR), is associated with inter-extremity differences in proteoglycan density, measured via T1ρ magnetic resonance imaging, in tibiofemoral articular cartilage 12 months following ACLR.

METHODS

Twenty-one individuals with a unilateral patellar-tendon autograft ACLR (10 women and 11 men, mean ± SD age 23.9 ± 2.7 years, mean ± SD body mass index 23.9 ± 2.7 kg/m² ) were recruited for participation in this study. Walking speed was collected using 3-dimensional motion capture at 6 and 12 months following ACLR. The articular cartilage of the medial femoral condyle (MFC) and lateral femoral condyle and medial and lateral tibial condyles was manually segmented and subsectioned into 3 regions of interest (anterior, central, and posterior) based on the location of the meniscus in the sagittal plane. Inter-extremity mean T1ρ relaxation time ratios (T1ρ ACLR extremity / T1ρ contralateral extremity) were calculated and used for analysis. Pearson product-moment correlations were used to determine associations between walking speed and inter-extremity differences in T1ρ relaxation time ratios.

RESULTS

Slower walking speed 6 months post-ACLR was significantly associated with higher T1ρ relaxation time ratios in the MFC of the ACLR extremity 12 months following ACLR (posterior MFC, r = -0.51, P = 0.02; central MFC, r = -0.47, P = 0.04). Similarly, slower walking speed at 12 months post-ACLR was significantly associated with higher T1ρ relaxation time ratios in the posterior MFC ACLR extremity (r = -0.47, P = 0.04) 12 months following ACLR.

CONCLUSION

Slower walking speed at 6 and 12 months following ACLR may be associated with early proteoglycan density changes in medial femoral compartment cartilage health in the first 12 months following ACLR.

Comparing the effects of mechanical perturbation training with a compliant surface and manual perturbation training on joints kinematics after ACL-rupture

INTRODUCTION

Performing physical activities on a compliant surface alters joint kinematics and increases joints stiffness. However, the effect of compliant surface on joint kinematics after ACL-rupture is yet unknown.

AIM

To compare the effects of mechanical perturbation training with a compliant surface to manual perturbation training on joint kinematics after ACL-rupture.

METHODS

Sixteen level I/II athletes with ACL-rupture participated in this preliminary study. Eight patients received mechanical perturbation with compliant surface (Mechanical) and 8 patients received manual perturbation training (Manual). Patients completed standard gait analysis before (Pre) and after (Post) training.

RESULTS

Significant group-by-time interactions were found for knee flexion angle at initial contact (IC) and peak knee flexion (PKF) (p<0.004), with manual group significantly increased knee flexion angle at IC and PKF (p<0.03). Main effects of group were found for hip flexion angle at IC (Manual:34.34+3.51°, Mechanical:27.68+4.08°, p = 0.011), hip rotation angle at PKE (Manual:-3.40+4.78°, Mechanical:5.43+4.78°, p < 0.0001), and knee adduction angle at PKE (Manual:-2.00+2.23°, Mechanical:0.55+2.23°, p = 0.039). Main effects of time were found for hip adduction angle at PKE (Pre:6.98+4.48°, Post:8.41+4.91°, p = 0.04), knee adduction angle at IC (Pre:-2.90+3.50°, Post:-0.62+2.58°, p = 0.03), ankle adduction angle at IC (Pre:2.16+3.54, Post:3.8+3.68, p = 0.008), and ankle flexion angle at PKF (Pre:-4.55+2.77°, Post:-2.39+3.48°, p = 0.01).

DISCUSSION

Training on a compliant surface induces different effects on joint kinematics compared to manual perturbation training after ACL-rupture. Manual perturbation improved hip alignment and increased knee flexion angles, while mechanical training decreased knee flexion angles throughout the stance phase. Administering training on a compliant surface after ACL-rupture may help improving dynamic knee stability, however, long-term effects on knee health needs to be determined.

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.

Biomechanical assessment of an alternative method of staple fixation for anchoring the Bone Patellar Tendon Bone graft to the tibia

INTRODUCTION

The Anterior cruciate ligament (ACL) is the most commonly injured ligament around the knee and is best reconstructed with a biological graft. For ideal graft fixation, there should be sufficient initial strength to avoid failure of fixation and sufficient stiffness to restore the stability of the knee and to avoid gradual loosening in the post-operative period.When considering fixation of Bone Patellar Tendon Bone (BPTB) grafts to the tibia, the interference screw is considered to be the gold standard. As an alternative, we have used of staples and stainless steel (SS) wire to anchor the BPTB graft to the tibia and femur. The aim of this study was to assess the biomechanical efficacy of this fixation technique for anchoring the BPTB graft to the proximal tibia. We used a bovine model to compare three fixation techniques -interference screw, braided polyester sutures tied to a screw post and SS wire tied to a staple.

MATERIALS AND METHODS

Fifteen fresh bovine knees specimens were used for the study. The patella was fixed to a load cell and the construct was pre-tensioned to 40N to allow for creep of the tendon. The BPTB graft was fixed to the tibia using the three fixation techniques - the interference screw, polyester suture tied to a post, and SS wire anchored to a staple. After fixation, the graft was subjected to a single load to failure test, and the forces generated were recorded. The ultimate failure load (the pullout strength), stiffness, and mode of failure were noted.

RESULTS

In the single load-to-failure biomechanical testing, the ultimate failure load and stiffness for Staple with SS wire were 726.40N and 61.9N/mm respectively. For the screw post and polyester suture, it was 733.20N and 53.22N/mm, and for Interference screw - 594.00N and 79.50 N/mm respectively. There was no statistically significant difference in the stiffness or ultimate failure load between the three fixation techniques. The graft fixation using interference screws failed at the bone- tunnel interface by slippage of the bone block from the tunnel in all 5 specimens. In all 5 of the specimens fixed with polyester suture and the screw post, the fixation failed when the polyester suture snapped. When the SS wire and staple construct was stressed, the graft failed as the SS wire cut through the graft in 4 specimens, and in the fifth construct, the knot over the staple unraveled as the load was applied.

CONCLUSION

The biomechanical properties of BPTB graft fixation with SS wire tied to a staple is similar to that of other fixation devices like the interference screw and suture post. This technique provides a simple, yet effective fixation for the graft - but needs further clinical assessment.

Clinical Outcomes of Single Anteromedial Bundle Biologic Augmentation Technique for Anterior Cruciate Ligament Reconstruction With Consideration of Tibial Remnant Size

PURPOSE

The primary aim of this study was to evaluate the functional outcomes, knee stability, complications, and reoperations associated with anatomic anterior cruciate ligament (ACL) reconstruction using the single anteromedial bundle biological augmentation (SAMBBA) technique in a consecutive series of 128 patients with a minimum follow-up of 24 months. A secondary aim was to compare larger preserved ACL remnants with smaller preserved remnants.

METHODS

Patients who underwent primary anatomic ACL reconstruction using the SAMBBA technique from July 2013 to October 2014 were analyzed. Exclusion criteria were (1) age <16 years, (2) revision cases, (3) multiple ligament injuries, (4) chondral lesions greater than grade 2 according to the Outerbridge classification, (5) additional injuries to the collateral ligaments greater than grade 2, or (6) a history of a contralateral ACL injury. Clinical assessment including evaluation of side-to-side difference and functional outcome measures with the International Knee Documentation Committee (IKDC) subjective score and the Tegner Activity Scale were used to evaluate outcomes before surgery and at the last follow-up. Any subsequent surgical procedures were systematically recorded during the study period. The patients were also divided in 2 groups according to their ACL remnant size, ≥50% or <50%, and compared.

RESULTS

Of the 135 patients who underwent primary SAMBBA technique, 128 patients returned to final follow-up, with a mean follow-up of 31.7 months (range, 24-44.3). At last follow-up, the IKDC score significantly improved from 54.1 ± 15.1 to 92.5 ± 11.4 (P < .001); the Tegner activity score (6.4 ± 1.2) was similar (P = .3) to the preinjury score (6.5 ± 1.2). Side-to-side laxity significantly improved from 6.7 ± 1.2 mm to 0.7 ± 1 mm (P < .001). Twenty-four subsequent surgeries (18.7%) were performed including 10 meniscal procedures, 7 ACL revisions, 5 arthroscopies for cyclops lesions, one microfracture, and one manipulation under anaesthesia. The side-to-side laxity (P = .30) and rates of reoperation (P = .65), graft failure (P = .45), and cyclops lesions (P = .67) were not significantly different between ≥50% or <50% ACL remnant groups.

CONCLUSIONS

The results of this study demonstrate that primary anatomic ACL reconstruction using the SAMBBA technique significantly improved clinical and functional outcomes between baseline and follow-up at a minimum of 24 months. A low rate of complications was observed with this technique. No significant differences between large and moderate size ACL remnants were detected for all outcome measures.

LEVEL OF EVIDENCE

Level IV case series with subgroup analysis.

Young athletes after ACL reconstruction with quadriceps strength asymmetry at the time of return-to-sport demonstrate decreased knee function 1 year later

PURPOSE

Quadriceps femoris (QF) strength deficits at return-to-sport (RTS) after ACL reconstruction (ACLR) contribute to decreased knee function at the same time point. However, the impact of QF strength at RTS on longitudinal function has not been examined. The purpose of this study was to test the hypothesis that young athletes after ACLR with QF strength asymmetry at RTS would demonstrate decreased knee-related function and lower proportions of functional recovery at 1 year post-RTS compared to young athletes following ACLR with nearly symmetric QF strength at RTS.

METHODS

Participants included 76 young athletes (74% female; mean age at RTS = 17.3 years) after primary, unilateral ACLR, cleared to RTS, and followed for 1 year after RTS. At the time of RTS, QF strength was quantified on an isokinetic dynamometer and a Limb Symmetry Index (LSI) was calculated [(involved/uninvolved) × 100%]. The cohort was subdivided into two groups based on RTS QF LSI: high quadriceps (HQ; LSI ≥ 90%; n = 36) and low quadriceps (LQ; LSI < 85%; n = 36). The cohort was followed for 1 year post-RTS, and knee-related function was assessed using the International Knee Documentation Committee subjective form (IKDC), the Knee Injury and Osteoarthritis Outcome Score (KOOS), and LSI of single-leg hop tests. Functional recovery at 1 year post-RTS was defined as KOOS scores above literature-reported cut-offs.

RESULTS

While the HQ group demonstrated higher symmetry on all 1 year post-RTS hop tests, only the triple-hop test (p = 0.020) was found to be statistically different. Similarly, while the HQ group scored higher on all 1 year post-RTS self-reported knee function measures, only differences on the KOOS-Sport/Rec score (p = 0.039) and IKDC score (p = 0.011) were statistically different. Additionally, the HQ group demonstrated higher proportions of functional recovery at 1 year post-RTS than the LQ group on the KOOS-Symptoms (HQ: 88.9%, LQ: 69.4%; p = 0.040) and KOOS-Sport/Rec (HQ: 91.7%, LQ: 69.4%; p = 0.017).

CONCLUSIONS

Young athletes after ACLR with QF strength asymmetry at RTS demonstrated decreased knee-related function and lower proportions of functional recovery at 1 year post-RTS. However, group differences did not exceed reported minimal clinically important difference values. Further study is warranted to understand factors that contribute to longitudinal knee function after ACLR. Clinicians should focus on restoring symmetric QF strength at RTS after ACLR, which may promote higher longitudinal knee function.

LEVEL OF EVIDENCE

Level II, Prospective cohort study.

Comparative Study after Hamstring Anterior Cruciate Ligament Reconstruction with Endobutton and Rigidfix: A Clinical Trial Study

Background

One of the most common orthopedic clinic visits involves direct and indirect knee trauma leading to rupture of anterior cruciate ligament (ACL). Endobutton and Rigidfix are most frequent treating methods that used by orthopedic surgeons. Thus the aim of this study was compare the clinical results of reconstructing arthroscopic ACL of the knee through two methods namely Rigidfix and Endobutton.

Materials and Methods

In a clinical trial study, a total of 40 patients with rupture of ACL were selected and randomly divided into two groups. The groups were treated through fixation procedures either Endobutton or Rigidfix. Prior to surgery and then at least 2 years after surgery, the patients were under physical examination in terms of knee range of motion, knee stability, knee pain, ability to perform daily activities and exercises and compared between the two groups.

Results

The knee range of motion in Endobutton and Rigidfix were 135.73 ± 2.63 and 129.87 ± 7.14° resprectively (P = 0.06). comparing two groups, during last month in Endobutton and Rigidfix the frequency of knee pain were 2.5 ± 1.4 and 3.4 ± 1.4 respectively (P = 0.08). Moreover, the pain intensity score were 2.9 ± 1.5 and 2.6 ± 1.1 (P = 0.49). But there was a significant difference observed in patients' satisfaction and ability to perform sports activities.

Conclusions

The two fixation methods namely Endobutton and Rigidfix are not preferred over one another. But patients' satisfaction and ability to perform sports activities in Endobutton was better than the Rigidfix.

Development of Tissue-Engineered Ligaments: Elastin Promotes Regeneration of the Rabbit Medial Collateral Ligament

When ligaments are injured, reconstructive surgery is sometimes required to restore function. Methods of reconstructive surgery include transplantation of an artificial ligament and autotransplantation of a tendon. However, these methods have limitations related to the strength of the bone-ligament insertion and biocompatibility of the transplanted tissue after surgery. Therefore, it is necessary to develop new reconstruction methods and pursue the development of artificial ligaments. Elastin is a major component of elastic fibers and ligaments. However, the role of elastin in ligament regeneration has not been described. Here, we developed a rabbit model of a medial collateral ligament (MCL) rupture and treated animal knees with exogenous elastin [100 µg/(0.5 mL·week)] for 6 or 12 weeks. Elastin treatment increased gene expression and protein content of collagen and elastin (gene expression, 6-fold and 42-fold, respectively; protein content, 1.6-fold and 1.9-fold, respectively), and also increased the elastic modulus of MCL increased with elastin treatment (2-fold) compared with the controls. Our data suggest that elastin is involved in the regeneration of damaged ligaments.

Influence of Medial Hamstring Tendon Harvest on Knee Flexor Strength after Anterior Cruciate Ligament Reconstruction

Background

The advantages of hamstring tendon autografts for anterior cruciate ligament reconstruction are well known; however, concerns have arisen regarding the influence of hamstring tendon harvest on postoperative weakness in knee flexion.

Purpose

To evaluate the influence of hamstring tendon harvest on knee flexion strength in patients undergoing anterior cruciate ligament reconstruction.

Study Design

Prospective randomized study.

Methods

Ninety patients were randomly assigned at surgery to undergo anterior cruciate ligament reconstruction with either a semitendinosus tendon autograft or a semitendinosus and gracilis tendon autograft. Quadriceps and hamstring muscle strength was tested before surgery and at 6, 12, and 18 months after surgery.

Results

There was no significant difference in clinical results between the groups and neither group showed a significant decrease in isokinetic hamstring muscle strength. However, when the subjects’ knees were at positions of 70° or more of flexion, both isokinetic and isometric measurements revealed a significant decrease in hamstring muscle strength in both groups. The strength in the group with semitendinosus and gracilis tendons was considerably less than that in the group with semitendinosus tendon alone at 18 months.

Conclusions

Tendon harvest causes significant weakness of hamstring muscle strength at high knee flexion angles, but such weakness can be minimized if the gracilis tendon is preserved.

Performance-Based Outcomes After Anterior Cruciate Ligament Reconstruction in Professional Athletes Differ Between Sports

BACKGROUND

Excellent outcomes have been reported for anterior cruciate ligament (ACL) reconstruction (ACLR) in professional athletes in a number of different sports. However, no study has directly compared these outcomes between sports.

PURPOSE

To determine if differences in performance-based outcomes exist after ACLR between professional athletes of each sport.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

National Football League (NFL), National Basketball Association (NBA), National Hockey League (NHL), and Major League Baseball (MLB) athletes undergoing primary ACLR for an acute rupture were identified through an established protocol of injury reports and public archives. Sport-specific performance statistics were collected before and after surgery for each athlete. Return to play (RTP) was defined as a successful return to the active roster for at least 1 regular-season game after ACLR.

RESULTS

Of 344 professional athletes who met the inclusion criteria, a total of 298 (86.6%) returned to play. NHL players had a significantly higher rate of RTP (95.8% vs 83.4%, respectively; P = .04) and a shorter recovery time (258 ± 110 days vs 367 ± 268 days, respectively; P < .001) than athletes in all the other sports. NFL athletes experienced significantly shorter careers postoperatively than players in all the other sports (2.1 vs 3.2 years, respectively; P < .001). All athletes played fewer games ( P ≤ .02) 1 season postoperatively, while those in the NFL had the lowest rate of active players 2 and 3 seasons postoperatively (60%; P = .002). NBA and NFL players showed decreased performance at season 1 after ACLR ( P ≤ .001). NFL players continued to have lower performance at seasons 2 and 3 ( P = .002), while NBA players recovered to baseline performance.

CONCLUSION

The data indicate that NFL athletes fare the worst after ACLR with the lowest survival rate, shortest postoperative career length, and sustained decreases in performance. NHL athletes fare the best with the highest rates of RTP, highest survival rates, longest postoperative career lengths, and no significant changes in performance. The unique physical demand that each sport requires is likely one of the explanations for these differences in outcomes.

Prevention and Management of Post-operative Complications Following ACL Reconstruction

PURPOSE OF REVIEW

The goal of this paper is to review the current management and prevention of post-operative complications after anterior cruciate ligament (ACL) reconstruction. Trends in rehabilitation techniques will be presented, in addition to suggestions for interventions and expected milestones in ACL reconstruction recovery.

RECENT FINDINGS

ACL reconstruction protocols have evolved to more of a criterion-based progression rather than a tissue-healing time frame. Given the evolution of ACL surgical reconstruction techniques and rehabilitation protocols, the risk of post-operative complications can arise both early and late in the recovery process. This paper will discuss the role of preventative measures as it applies to the post-operative patient with ACL reconstruction. Short-term complications following ACL reconstruction include infection and deficits to knee motion and strength, whereas long-term complications include secondary ACL injury to either the involved or contralateral knee and lack of ability to return to high-level sports following this procedure. Future research should continue to address the multifactorial causes of secondary ACL injury and limited ability of patients to return to high level activities.

Return to Play and Player Performance After Anterior Cruciate Ligament Injury in Elite Australian Rules Football Players

Background:

Australian Rules football is a highly aerobic and anaerobic game that at times requires players to perform cutting or pivoting maneuvers, potentially exposing them to anterior cruciate ligament (ACL) injury. At present, there are limited data available addressing the impact of ACL injury on return to play and preinjury form after ACL reconstruction.

Purpose:

To determine the prevalence of ACL injury and the incidence of further ACL injury, and to consider player return to play and return to preinjury form after ACL reconstruction. It was hypothesized that elite-level Australian Football League (AFL) players do not return to preinjury form until, at minimum, 2 years after returning to play.

Study Design:

Case series; Level of evidence, 4.

Methods:

A retrospective analysis was undertaken on a cohort of elite AFL players who injured their ACL between 1990 and 2000. Return to play after ACL reconstruction was determined by the mean number of ball disposals, or release of the ball by the hand or foot, at 1, 2, and 3 years after return to play and compared with preinjury form. Associations between player and injury characteristics, method of reconstruction, and outcomes (return to play, preinjury form, and further ACL injury) were examined.

Results:

During the included seasons, a total of 2723 AFL players were listed. Of these, 131 (4.8%) sustained an ACL injury, with 115 players eligible for inclusion. Of 115 players, 26% did not return to elite competition, while 28% of those who did return experienced further ACL injury. The adjusted mean number of disposals (± standard error of the mean) was significantly lower at 1 year (12.21 ± 0.63; P = .003), 2 years (12.09 ± 0.65; P = .008), and 3 years (11.78 ± 0.77; P = .01) after return to play compared with preinjury (14.23 ± 0.67). On average, players did not return to preinjury form by 3 years (P < .01). Players aged 30 years or older were less likely to return to play compared with younger players (P = .0002), moderate-weight players were more likely to return to play compared with lighter-weight players (P = .007), and there were significantly increased odds of not returning to play if the dominant side was injured (odds ratio, 0.10; 95% CI, 0.03-0.34; P = .0002).

Conclusion:

On average, AFL players do not return to their preinjury form after ACL injury and reconstruction, a common injury in this sporting population. This along with the high occurrence of reinjury highlights the career-threatening nature of ACL injury for elite AFL players.

Return to Sport and Performance After Anterior Cruciate Ligament Reconstruction in National Football League Linemen

BACKGROUND

Tears of the anterior cruciate ligament (ACL) are common in the National Football League (NFL). The impact of these injuries on the careers of NFL linemen is unknown.

PURPOSE

To define the percentage of NFL linemen who return to sport (RTS) after ACL reconstruction, the mean time to RTS, and the impact on performance compared with matched controls.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Data on NFL offensive and defensive linemen who sustained an ACL tear and underwent ACL reconstruction between 1980 and 2015 were analyzed. Players were identified through NFL team websites, publicly available injury reports, player profiles, and press releases. Demographics and mean in-game performance data preinjury and post-ACL reconstruction were recorded. A player was deemed to have returned to sport if he played in at least 1 NFL game after his ACL reconstruction. A healthy control group was selected to compare in-game performance data and was matched with the study group on several parameters.

RESULTS

Overall, 73 NFL linemen met the inclusion criteria; 47 (64.3%) returned to play after ACL reconstruction (62.5% of offensive linemen, 65.9% of defensive linemen). All offensive linemen successfully returned to play the season after injury. No difference existed in number of seasons, total number of games played, mean number of games played, or mean number of games started per season when offensive linemen who RTS after ACL reconstruction were compared with matched controls (all P > .05). Among defensive linemen who RTS, most returned the season after injury (88.9%). There was no difference between defensive linemen who RTS after ACL reconstruction and matched controls in any performance metrics as an average over the remainder of their career (all P > .05). However, NFL defensive linemen who tore their ACL played fewer total seasons than matched controls (P = .020).

CONCLUSION

Overall, 64.3% of NFL offensive and defensive linemen who undergo ACL reconstruction returned to play. Linemen who RTS do so at a high level, with no difference in in-game performance or career duration when compared with matched controls.

Biomechanical Factors Associated With Pain and Symptoms Following Anterior Cruciate Ligament Injury and Reconstruction

BACKGROUND

Few studies have investigated the associations between patient-reported outcome and gait in patients with anterior cruciate ligament (ACL) injury and reconstruction over time. Because there is an association between ACL rupture and the presence of osteoarthritis later in life, a better understanding of these relationships will help to elucidate how patients' gait pattern may affect pain and symptoms, potentially leading to better treatment for or preventing the development of knee OA.

OBJECTIVE

To evaluate the associations between gait characteristics and self-reported pain and symptoms before, 6 months after, and 1 year after anterior cruciate ligament reconstruction.

DESIGN

Prospective cohort study.

SETTING

The Human Performance Center at the Orthopedic Institute at the University of California, San Francisco.

PATIENTS

Patients with full unilateral ACL tears were enrolled. A total of 43 patients were included at 12 months postsurgery.

METHODS

The independent variable in this study comprised specific gait variables in patients who had undergone ACL reconstruction. At each time point, 3-dimensional motion analysis was performed. Participants also completed the Knee Osteoarthritis Outcome Score (KOOS) questionnaire.

MAIN OUTCOMES MEASUREMENTS

The primary study outcome measurement was the KOOS and was planned before data collection began. Partial correlations were used to examine cross-sectional associations between gait characteristics and KOOS pain and symptom scores at all time points. In addition, partial correlations were performed to examine the associations between change in postoperative KOOS from 6 months to 1 year and gait characteristics at baseline and 6 months.

RESULTS

Significant associations between KOOS and gait characteristics were found at all time points, including an association between peak medial ground reaction force and pain (r = -0.344, P = .02) and symptoms (r = -0.407, P = .007) at baseline.

CONCLUSIONS

Specific gait variables may be predictive of greater pain and symptoms and less improvement over time postreconstruction. This could help to inform rehabilitation exercises post injury and pre reconstruction.

LEVEL OF EVIDENCE

IV.

The Effect of Graft Pretensioning on Bone Tunnel Diameter and Bone Formation After Anterior Cruciate Ligament Reconstruction in a Rat Model: Evaluation With Micro-Computed Tomography

BACKGROUND

Moderate graft pretensioning in anterior cruciate ligament (ACL) reconstruction is paramount to restore knee stability and normalize knee kinematics. However, little is known about the effect of graft pretensioning on graft-to-bone healing after ACL reconstruction.

HYPOTHESIS

Moderate graft pretensioning will improve bone formation within the bone tunnel after ACL reconstruction, resulting in superior load to failure.

STUDY DESIGN

Controlled laboratory study.

METHODS

67 male Sprague-Dawley rats underwent unilateral ACL reconstruction with a flexor digitorum longus tendon autograft. The graft was subjected to pretensioning forces of 0 N, 5 N, or 10 N. Custom-made external fixators were used for knee immobilization postoperatively. Rats were euthanized for biomechanical load-to-failure testing (n = 45) and micro-computed tomography (μCT) examination (n = 22) at 3 and 6 weeks after surgery. Three regions of each femoral and tibial bone tunnel (aperture, middle, and tunnel exit) were chosen for measurement of tunnel diameter and new bone formation.

RESULTS

Biomechanical tests revealed significantly higher load-to-failure in the 5-N graft pretensioned group compared with the 0- and 10-N groups at 3 weeks (8.58 ± 2.67 N vs 3.96 ± 1.83 N and 4.46 ± 2.62 N, respectively) and 6 weeks (16.56 ± 3.50 N vs 10.82 ± 1.97 N and 7.35 ± 2.85 N, respectively) after surgery ( P < .05). The mean bone tunnel diameters at each of the 3 regions were significantly smaller in the 5-N group, at both the femoral and tibial tunnel sites, than in the 0- and 10-N groups ( P < .05). At 3 and 6 weeks postoperatively, the bone mineral density, bone volume fraction, and connectivity density around the aperture and middle regions of the tibial bone tunnels were all significantly higher in the 5-N group compared with the 0- and 10-N groups ( P < .05). In the aperture and middle regions of the femoral bone tunnels, pretensioning at either 5 or 10 N resulted in increased bone formation compared with the nonpretensioned group at 3 weeks postoperatively. No differences were found in bone formation between any of the 3 femoral tunnel regions at 6 weeks.

CONCLUSION

Graft pretensioning can stimulate new bone formation and improve tendon-to-bone tunnel healing after ACL reconstruction.

CLINICAL RELEVANCE

Optimal graft pretensioning force in ACL reconstruction can improve bone tunnel healing. Further study is necessary to understand the mechanisms underlying the effect of graft pretensioning on healing at the bone-tunnel interface.

Combined reconstruction of the anterior cruciate ligament associated with anterolateral tenodesis effectively controls the acceleration of the tibia during the pivot shift

PURPOSE

The pivot shift test is quantified subjectively during assessment of patients presenting with suspected Anterior Cruciate Ligament (ACL) tears and has a low interobserver reproducibility. The Kinematic Rapid Assessment (KiRA) is a triaxial accelerometer that makes it possible to non-invasively quantify tibial acceleration during the pivot shift test. Abolishing pivot shift is considered to be a key element in surgical reconstruction but is incomplete in 25-38% of patients.

METHODS

Patients were included prospectively. Inclusion criteria were patients requiring ACL reconstruction associated with at least one of the following factors corresponding to the patient who have a high risk of rupture either by their sports activity, a failure case, or the notion of important rotational laxity: the patient practiced a competitive pivot-contact sport, revision ACL reconstruction (besides STG (semitendinosus-gracilis graft) repair), subjective explosive rotational laxity, Segond fracture, and TELOS value of >10 mm. Standardized pre- and postoperative pivot shift tests were immediately performed under anesthesia in both knees.

RESULTS

Forty-three patients were included. Mean preoperative variations in tibial acceleration in the healthy and injured knees were 1.2 ± 0.1 and 2.7 ± 0.3 m/s², respectively, p < 0.01. A statistically significant decrease in immediate postoperative mean variations in acceleration in the injured knee occurred: 1.5 ± 0.3 m/s², p < 0.01. There was no longer any statistical difference between postoperative contralateral healthy knees and operated knees (n.s).

CONCLUSIONS

Combined ACL reconstruction associated with anterolateral tenodesis suppress acute pathologic tibial acceleration in the pivot shift.

LEVEL OF EVIDENCE

III.

Clinical outcomes and biomechanical analysis of posterolateral bundle augmentation in patients with partial anterior cruciate ligament tears

PURPOSE

To examine the clinical and biomechanical results of posterolateral (PL) augmentation to reconstruct damaged PL bundle while preserving the less-damaged anteromedial bundle for partial anterior cruciate ligament (ACL) tears in comparison with double-bundle ACL reconstruction.

METHODS

Sixteen patients who underwent PL augmentation for partial ACL tears (Group P) and 37 patients who underwent double-bundle ACL reconstructions for complete ACL tears were examined (Group D). Anterior tibial translation (ATT) was evaluated using the KT-1000 arthrometer. ATT during the Lachman test and acceleration of posterior tibial translation (APT) during the pivot shift test were evaluated using an electromagnetic measurement system (EMS). Clinical outcomes were evaluated using the Lysholm score. Second-look arthroscopy was performed 1 year after surgery.

RESULTS

The mean postoperative Lysholm scores were 91.7 ± 12.2 and 94.6 ± 7.2 in Groups P and D, respectively, and there was no statistically significant difference between the two groups. The mean side-to-side difference of ATT on the KT-1000 was significantly improved in both Groups P and D. In the EMS analysis, the mean side-to-side difference of ATT and the mean APT were significantly improved in both Groups P and D. There was no significant difference in the second-look evaluation between the two groups.

CONCLUSIONS

The clinical and biomechanical outcomes of PL augmentation were satisfactorily comparable to those of double-bundle ACL reconstruction. PL augmentation could be a useful treatment option for patients with partial ACL tears.

LEVEL OF EVIDENCE

IV.

Bone contusion progression from traumatic knee injury: association of rate of contusion resolution with injury severity

BACKGROUND

Bone contusions are frequently encountered in magnetic resonance imaging (MRI) evaluation of knee anterior cruciate ligament (ACL) injuries. Their role as indicators of injury severity remains unclear, primarily due to indeterminate levels of joint injury forces and to a lack of preinjury imaging.

PURPOSE

The purpose of this study was to 1) quantify bone contusion pathogenesis following traumatic joint injuries using fixed imaging follow-ups, and 2) assess the feasibility of using longitudinal bone contusion volumes as an indicator of knee injury severity.

STUDY DESIGN

Prospective sequential MRI follow-ups of a goat cohort exposed to controlled stifle trauma in vivo were compared to parallel clinical MRI follow-ups of a human ACL tear patient series.

METHODS

Reproducible cartilage impact damage of various energy magnitudes was applied in a survival goat model, coupled with partial resection of anterior portions of medial menisci. Both emulate injury patterns to the knee osteochondral structures commonly encountered in human ACL injury imaging as well as instability from resultant ligament laxity. Longitudinal clinical MRI sequences portrayed stifle bone contusion evolution through 6 months after the inciting event.

RESULTS

In the first 2 weeks, biological response variability dominated the whole-joint response with no apparent correlation to trauma severity. Control goats subjected to partial meniscectomy alone exhibited minimal bone response. Thereafter, 0.6 J impact bone contusions portrayed a faster rate of resolution than those induced by 1.2 J cartilage impacts.

CONCLUSION

Bone contusion sizes combined with time of persistence are likely better measures of joint injury severity than isolated bone contusion volume.

Clinical Predictors of Knee Mechanics at Return to Sport after ACL Reconstruction

PURPOSE

Despite significant rehabilitation, many athletes experience protracted weakness and faulty mechanics after anterior cruciate ligament reconstruction (ACLR). Clinical tests performed early in rehabilitation, which predict knee mechanics at return-to-sport, are virtually unknown and critically needed to guide clinical decision making. The purpose of this study is to determine if quadriceps strength, Y balance anterior (YB-A) reach distance, and single-leg step-down test performance (SLSD) conducted 3 months post-ACLR are predictive of knee flexion excursion (KFLEX) and knee extensor moment (KEM) during running 6 months post-ACLR.

METHODS

Thirty (16 females) subjects were collected 3 and 6 months post-ACLR. Age, 21.3 ± 7.6 yr; mass, 69.85 ± 11.4 kg; height, 1.73 ± 0.09 m. At 3 months post-ACLR, subjects performed isometric quadriceps strength testing, YB-A, and SLSD assessments. At 6 months post-ACLR, subjects underwent three-dimensional motion analysis while running on an instrumented treadmill. Pearson correlation coefficients and stepwise multiple regression were used to assess the relationships of 3-month and 6-month variables.

RESULTS

Quadriceps strength (r = 0.493, P < 0.01), YB-A (r = 0.394, P = 0.03), and SLSD (r = 0.648, P < 0.01) were significantly correlated to KFLEX. Quadriceps strength (0.505, P < 0.01) and SLSD (.541, P < 0.01) were significantly correlated with KEM, whereas YB-A (.276, P = 0.06) was not. SLSD and quadriceps strength were predictive of KEM (adj R², 0.36; P = 0.001) whereas only SLSD was predictive of KFLEX (adj R², 0.40; P < 0.001).

CONCLUSIONS

After ACLR, better performance in SLSD and quadriceps strength 3 months postsurgery is predictive of improved sagittal plane knee mechanics during running 6 months postsurgery.

Conscious performance and arthroscopic findings in athletes with anterior cruciate ligament injuries treated via conservative therapy during the competitive season

PURPOSE

Athletes often receive conservative treatment for injured anterior cruciate ligaments (ACLs) so that they can continue to play to the end of their season. The purpose of this study was to examine the conscious performance and arthroscopic findings of athletes who received conservative therapy for ACL injuries.

METHODS

Forty-two patients with ACL injuries underwent conservative treatment. After the season ended, ACL reconstruction was performed. We examined the following parameters: (1) time required for return to competition after injury, (2) conscious performance after return to competition, (3) whether the injured knee gave way during conservative therapy or after return to competition, and (4) cause of performance deterioration if applicable. To determine conscious performance, patients were asked to rate their performance after therapy relative to their performance before injury.

RESULTS

Thirty-eight of the 42 patients (90.5%) returned to competition after conservative treatment. The mean time to return was 13.8 ± 7.6 weeks, and the mean conscious performance score was 58.4 ± 16.5%. Thirty-eight patients (90.5%) experienced their knee giving way, of whom 36 (94.9%) stated that fear of their knee giving way hampered their performance. At the time of ACL reconstruction, 9 patients had chondral injuries and 22 patients had meniscus injuries.

CONCLUSION

Most athletes with damaged ACLs returned to the field within the same season after conservative treatment. However, conscious performance was only about 60%. It is possible that knees giving way caused secondary meniscus and joint cartilage damage. Therefore, conservative treatment of individuals with ACL injuries should be considered carefully.

Reliability of 3-Dimensional Computed Tomography for Application of the Bernard Quadrant Method in Femoral Tunnel Position Evaluation After Anatomic Anterior Cruciate Ligament Reconstruction

PURPOSE

To validate whether the Bernard quadrant method, which was developed for application on simple lateral radiography, can be used with 3-dimensional computed tomography (3D CT) to localize the femoral insertion of the reconstructed anterior cruciate ligament (ACL).

METHODS

We analyzed 32 knees with ACL tears that were reconstructed using a metal interference screw for fixation at the femoral tunnel between March 2012 and May 2013. Postoperative lateral radiographs and 3D CT images were obtained 7 days after the operation. By use of the Bernard quadrant method, the location of the femoral tunnel was measured by 2 orthopaedic surgeons by locating the position of the metal interference screw using 3D CT imaging and simple lateral knee radiography. The correlation between the femoral tunnels on the 2 radiographic images was compared using the MedCalc statistical analysis program.

RESULTS

On the 3D CT image, the position of the femoral insertion of the ACL as measured by the position of the metal screw head was 36.3% ± 6.0% in the x-coordinate and 39.6% ± 9.1% in the y-coordinate compared with 37.6% ± 5.8% and 41.0% ± 11.6%, respectively, on the simple radiograph. The Pearson correlation coefficients between 3D CT and simple radiography were 0.840 for the x-coordinate and 0.858 for the y-coordinate. Intraobserver reliability and interobserver reliability for both coordinates were greater than 0.9 on 3D CT.

CONCLUSIONS

Application of the Bernard quadrant method on 3D CT showed high correlation to the originally described method using lateral radiographs and can be used reliably for localizing the reconstructed ACL.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Anterior cruciate ligament rupture and management

Anterior cruciate ligament rupture is a common knee injury in young people. It is the commonest cause of an acute haemarthrosis following trauma. Acute management involves aspiration, the restoration of full movement, followed by muscle rehabilitation. The long-term natural history of non-operative management is usually a failure to return to high level sports and in most, symptomatic instability with secondary meniscal and chondral injury. The late outcome is that of premature degenerative arthritis. Reconstructive techniques are now advanced and minimally invasive. However, considerable technical skill and experience is required to avoid complications. Physiotherapy guided rehabilitation over 4-6 months is vital prior to a return to sport. The stabilised knee should reduce secondary injury and progressive degenerative disease. In the future an increased number of reconstructions, tissue engineered grafts and accelerated healing will probably be seen.

Pain in donor site after BTB-ACL reconstruction with PRGF: a randomized trial

INTRODUCTION

Anterior cruciate ligament (ACL) tears are highly incident injuries in young athletes within our work area. The use of the patellar graft, despite being the treatment of choice, presents post-operative problems such as anterior knee pain, which limits its use and leads to preference being taken for alternative grafts. Our aim was to evaluate if the application of PRGF reduces anterior knee pain in donor site in BTB-ACL reconstruction.

MATERIALS AND METHODS

43 patients were included in the double-blinded and randomized clinical trial comparing two patient groups who underwent ACL reconstruction using patellar tendon graft, comparing anterior knee pain with and without the application of PRGF at the donor site after harvesting the graft.

RESULTS

The PRGF group showed decreased donor site pain in comparison to the control group, with significant differences in the first two months of follow-up.

CONCLUSION

The application of PRGF decreased donor site pain compared to the control group.

Two-Stage Revision Anterior Cruciate Ligament Reconstruction

The number of primary anterior cruciate ligament (ACL) tears is rapidly increasing. In patients who wish to return to their preoperative level of function, specifically as it pertains to participation in sports, the gold standard of treatment following an ACL tear remains an anterior cruciate ligament (ACL) reconstruction. Despite a majority of good/excellent results following primary ACL reconstruction, there is a growing subset of patients with persistent or recurrent functional instability who require revision ACL reconstruction. Preoperative planning for revision ACL reconstruction requires a careful understanding of the root cause of ACL failure, including possible technical causes of primary ACL failure and the presence of combined knee pathology that was not addressed at the index ACL reconstruction. The decision to perform 2-stage revision ACL reconstruction is multifactorial and is reached by technical considerations that may make a 1-stage revision less optimal, including tunnel widening, arthrofibrosis, active infection, and others. Concomitant knee pathology such as meniscal deficiency, malalignment (including an increase in posterior tibial slope), chondral lesions, and other ligamentous laxity may also require a staged approach to treatment. This evidence-based review covers the indications for 2-stage revision ACL reconstruction, surgical techniques, evidence for and technique of bone grafting prior ACL tunnels, and outcomes of 2-stage revision stratified by initial cause of ACL reconstruction failure. With proper preoperative planning and an understanding of the cause of failure following the primary ACL reconstruction, revision ACL reconstruction can offer excellent outcomes in the motivated patient. [Orthopedics. 2016; 39(3):e456-e464.].

Relationship between synovial fluid biomarkers of articular cartilage metabolism and the patient's perspective of outcome depends on the severity of articular cartilage damage following ACL trauma

Anterior cruciate ligament (ACL) trauma often occurs in combination with injury to the articular cartilage of the knee, this can result in earlier radiographic evidence of post traumatic osteoarthritis (OA) of the knee compared to the contralateral, ACL intact knee; however, the biomechanical and biological mechanisms associated with the onset and progression of this disease are not understood. We sought to gain insight into the mechanisms by determining the relationship between articular cartilage injury associated with ACL trauma and the expression of synovial fluid biomarkers of articular cartilage metabolism, and to evaluate the relationship between these biomarkers and the patient's perspective of the outcomes. Synovial fluid samples were acquired from 39 ACL injured subjects at an average of 10 weeks after injury, and 32 control subjects with normal knees (documented with clinical exam and MRI assessment). Subjects in the ACL-injured group were classified as low-risk for future OA if they displayed an International Cartilage Repair Society (ICRS) Grade 2 articular cartilage lesion or less and high-risk for future OA if they had an ICRS Grade 3A articular cartilage lesion. The patient's perspective of the injury was evaluated with the Knee Injury and Osteoarthritis Outcomes Score (KOOS). There were no significant differences in mean concentrations of the markers of type II collagen metabolism (CPII, C2C, and C1,2C) or the aggrecan breakdown Alanine-Arginine-Glycine-Serine (ARGS) -fragment between control subjects and the subjects in the low- and high-risk groups (p-value range: 0.80-0.43). Associations between ARGS-aggrecan concentration and KOOS subscales of symptoms and pain were significantly different between the low- and high-risk groups (p = 0.03 and p = 0.01, respectively). Likewise, there was strong evidence in support of an association between the markers of type II collagen metabolism (C1,2C and CPII concentrations) and the KOOS subscale of pain between the low- and high-risk groups (p = 0.051 and 0.077, correspondingly). In ACL injured subjects with concomitant Grade 3A articular cartilage injuries, concentrations of synovial fluid ARGS-aggrecan were directly associated with improvements in KOOS symptoms and pain. These findings suggest the possible involvement of ARGS-aggrecan in a localized tissue repair response involving an increase in aggrecan turnover following severe knee trauma. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 34:820-827, 2016.

Are porcine flexor digitorum profundus tendons suitable graft substitutes for human hamstring tendons in biomechanical in vitro-studies?

INTRODUCTION

Although a plenty of studies exist assessing the strength of ligamentous fixation techniques using porcine flexor digitorum profundus tendons as graft substitutes for human hamstring tendons, there is no biomechanical study comparing these two tendons. To interpret the results obtained with porcine flexor digitorum profundus tendons, knowledge of their biomechanical properties is essential. The purpose of this study was to compare the biomechanical properties of human hamstring tendons and porcine flexor digitorum profundus tendons.

MATERIALS AND METHODS

A total of six human hamstring tendons and six porcine flexor digitorum profundus tendons were analysed in this study. Quadruple-bundle human hamstring tendons and double-bundle porcine flexor digitorum profundus tendons with a diameter of 9 mm were used. Specimens were placed into a tensile loading fixation of a servohydraulic testing machine. Biomechanical analysis included pretensioning of the constructs at 50 N for 10 min following cyclic loading of 1500 cycles between 50 and 200 N at 0.5 Hz for measurement of elongation. Subsequently, ultimate failure load and failure mode analysis were performed with a ramp speed of 20 mm/min.

RESULTS

Human hamstring tendons showed significantly higher maximum load to failure values compared to porcine flexor digitorum profundus tendons (1597 ± 179.6 N vs. 1109 ± 101.9 N; p = 0.035). Human hamstring tendons yielded significantly lower initial elongation during preload, but not during cyclical loading.

CONCLUSIONS

When porcine flexor digitorum profundus tendons are used as graft substitutes for human hamstring tendons in biomechanical studies, maximum load to failure is underestimated while elongation is comparable to that of human hamstring tendons. Transferring results of biomechanical studies into clinical practice, the lower maximum load to failure of porcine flexor digitorum profundus tendons needs to be taken into consideration.

RISKS AND CONSEQUENCES OF USING THE TRANSPORTAL TECHNIQUE IN RECONSTRUCTING THE ANTERIOR CRUCIATE LIGAMENT: RELATIONSHIPS BETWEEN THE FEMORAL TUNNEL, LATERAL SUPERIOR GENICULAR ARTERY AND LATERAL EPICONDYLE OF THE FEMORAL CONDYLE

Objective: Define a security zone to avoid possibles vascular and ligamentar complications during anterior cruciate ligament reconstruction. Methods: Arthroscopic reconstruction using the transtibial and transportal technique in cadaver knees was performed followed by dissection and measurement of the distance between the femoral tunnel and the proximal attachment of the lateral collateral ligament and the femoral tunnel and the lateral superior genicular artery. Results: The measure of the analysed distances show us an aproximation between the major branch of the lateral superior genicular artery and the femoral insertion of the colateral lateral ligament and the femoral tunnel during the transportal technique. Conclusion: We realize that the use of technical ship it to arthroscopic ACL reconstruction has a higher probability of injury to the lateral geniculate artery and insertion of the lateral collateral ligament, promoting post-surgical complications such as instability of the knee, osteonecrosis of the femoral condyle and ligamentização graft.

Anterior cruciate ligament tears for the primary care sports physician: what to know on the field and in the office

Anterior cruciate ligament (ACL) injuries are relatively common and can lead to knee dysfunction. The classic presentation is a non-contact twisting injury with an audible pop and the rapid onset of swelling. Prompt evaluation and diagnosis of ACL injuries are important. Acute treatment consists of cessation of the sporting activity, ice, compression, and elevation with evaluation by a physician familiar with ACL injuries and their management. The diagnosis is made with the use of patient history and physical examination as well as imaging studies. Radiographs may show evidence of a bony injury. MRI confirms the diagnosis and evaluates the knee for concomitant injuries to the cartilage, menisci and other knee ligaments. For active patients, operative treatment is often recommended while less-active patients may not require surgery. The goal of this review is to discuss the diagnosis of an ACL injury and provide clear management strategies for the primary-care sports medicine physician.

Impaired Quadriceps Rate of Torque Development and Knee Mechanics After Anterior Cruciate Ligament Reconstruction With Patellar Tendon Autograft

BACKGROUND

Rate of torque development (RTD) measures the ability of a muscle to produce torque quickly. Decreased quadriceps RTD may impair performance of sporting tasks after surgery. Currently, little is known about variations in quadriceps RTD between anterior cruciate ligament (ACL)-reconstructed and noninjured limbs.

PURPOSE

To determine the differences in RTD of the quadriceps, the rate and timing of knee extensor moment (KEM) development, and knee flexion excursion during running after ACL reconstruction with patellar tendon autograft.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

This study involved 21 patients (11 female) 6 months after ACL reconstruction with patellar tendon autograft (median [IQR]: age, 18 [16-20] years; mass, 68.18 [61.34-75] kg; height, 1.74 [1.66-1.78] m). Patients performed four 5-second maximal voluntary isometric strength trials of both limbs on an isokinetic dynamometer. RTD was calculated as the mean slope of the torque-time curve between 20% and 80% of total time to peak torque. Then, patients underwent 3-dimensional motion analysis while running on an instrumented treadmill at a self-selected running speed (mean ± SD, 2.68 ± 0.28 m/s). The rate of knee extensor moment (RKEM) was calculated as the mean slope of the moment curve between 10% and 30% of stance phase. Between-limb comparisons were determined with a paired t test for peak KEM, RKEM, knee flexion excursion during 10% to 30% of stance, and time to generate KEM.

RESULTS

In the reconstructed limb, deficits in the peak rate of quadriceps torque development compared with the noninjured limb existed both isometrically (RTD, 257.56 vs 569.11 Nm/s; P < .001) and dynamically (RKEM, 16.47 vs 22.38 Nm/kg·m·s; P < .001). The reconstructed limb also generated a KEM later in the stance phase compared with the noninjured limb (11.37% vs 9.61% stance; P < .001) and underwent less knee flexion excursion (15.5° vs 19.8°; P < .001).

CONCLUSION

After ACL reconstruction with patellar tendon autograft, patients have lower RTD and RKEM in the reconstructed limb. Deviations in RTD and the timing of the KEM can change the way the knee is loaded and can potentially increase injury risk and future development of posttraumatic osteoarthritis. Rehabilitation should consider exercises designed to improve RTD and prepare the limb for the demands of sport performance.

Rehabilitation Charges Associated With Anterior Cruciate Ligament Reconstruction

Background:

Pre- and postoperative rehabilitation are important to the management of patients with anterior cruciate ligament (ACL) reconstruction, but little attention has been given to the costs. This study evaluated the pre- and postoperative rehabilitation charges in patients with ACL reconstruction in the United States.

Hypothesis:

Patients receive preoperative rehabilitation less commonly than postoperative rehabilitation.

Study Design:

Retrospective database study.

Level of Evidence:

Level 4.

Methods:

Using the PearlDiver database, we identified patients undergoing ACL reconstruction from 2007 through 2011 using Current Procedural Terminology codes. The associated rehabilitation charges billed to insurance providers for 90 days preoperatively and 6 months postoperatively were categorized as physical therapy or as durable medical equipment (DME). The charges were examined by year and geographic region and represented as per-patient average charges (PPACs).

Results:

A total of 92,179 patients were identified in the study period. The PPAC for rehabilitation was $241 during the 90-day preoperative period and $1876 for the 6-month postoperative period. Patients averaged 2 preoperative sessions for physical therapy, with 44% of patients receiving preoperative rehabilitation in contrast with an average of 17 postoperative sessions per patient in 93% of patients. Rehabilitation charges were greater postoperatively than preoperatively (P < 0.05). Preoperatively, 24% of patients received a DME, while 35% received a DME postoperatively. Preoperative rehabilitation PPACs were highest in the Northeast, followed by Midwest, South, and West (P < 0.05). There were no significant differences in postoperative rehabilitation PPACs for geographic region (P = 0.43).

Conclusion:

Preoperative rehabilitation charges were lower than postoperative charges. A patient undergoing ACL reconstruction typically received 9 times more sessions of postoperative physical therapy than preoperative.

Clinical Relevance:

This study found that preoperative supervised rehabilitation for patients with ACL reconstruction was infrequent across the United States.

Femoral nerve block versus adductor canal block for postoperative pain control after anterior cruciate ligament reconstruction: A randomized controlled double blind study

Background:

The objective of this study was to evaluate the reliability of the postoperative pain control using adductor canal block (ACB) compared that using the femoral nerve block (FNB) in patients with anterior cruciate ligament reconstructions (ACLR).

Materials and methods:

One hundred and twenty-eight patients who had been scheduled to patellar graft ACLR were included in this double blind study, and were randomly allocated into two groups; group ACB and group FNB (64 patients each). All patients received general anesthesia. At the end of the surgery, patients in group FNB received a FNB and those in group ACB received an ACB. The postoperative pain (visual analog scale [VAS]) and muscle weakness were assessed in the postoperative care unit and every 6 h thereafter for 24 h. The total morphine requirements were also recorded.

Results:

Patients in group ACB had significantly higher VAS (at 18 h and 24 h), higher morphine consumption, but significantly less quadriceps weakness than those in group FNB.

Conclusion:

In patients with patellar graft ACLR, the ACB can maintain a higher quadriceps power, but with lesser analgesia compared with the FNB.

Rates of Deep Venous Thrombosis and Pulmonary Embolus After Anterior Cruciate Ligament Reconstruction: A Systematic Review

Context:

Venous thromboembolic (VTE) disease is thought to be an uncommon but serious problem after anterior cruciate ligament (ACL) reconstruction. Rates of VTE after ACL reconstruction are not well documented.

Objective:

To determine the rates of deep vein thrombosis (DVT) and symptomatic pulmonary emboli (PE) after ACL reconstruction.

Data Sources:

Five publicly available databases (PubMed, Cochrane Database of Systematic Reviews, Scopus, Embase, and CINAHL Complete) were utilized.

Study Selection:

All studies that screened patients for DVT and reported rates of DVT and PE after ACL reconstruction were eligible for inclusion. Level 5 evidence, cadaver, biomechanical, and basic science studies; studies reporting only multiligament reconstruction outcomes; studies where rates of DVT and PE could not be separated out from patients undergoing other types of arthroscopic knee procedures; and classification studies were excluded.

Study Design:

Systematic review.

Level of Evidence:

Level 4.

Data Extraction:

All study, subject, and surgical data were analyzed. Descriptive statistics were calculated.

Results:

Six studies met the inclusion criteria, with a mean Modified Colman Methodology Score of 30 ± 8.22. A total of 692 patients (488 men [70.5%]; mean age, 31.6 ± 2.82 years; mean follow-up, 7 ± 18.4 months) underwent ACL reconstruction using either semitendinosus-gracilis autograft (77.6%), bone–patellar tendon–bone (BTB) autograft (22%), or allograft (0.4%). No patient received postoperative pharmacological anticoagulation. Fifty-eight patients (8.4%) had a DVT (81% below knee and 19% above knee), while only 1 patient (0.2%) had a symptomatic PE. When reported, 27% of DVT episodes were symptomatic.

Conclusion:

The rate of DVT after ACL reconstruction in patients who did not receive postoperative pharmacological anticoagulation is 8.4%, while the rate of symptomatic PE is 0.2%. Of the DVT episodes that occurred, 73% were asymptomatic.

The Effect of Cyclooxygenase Inhibition on Tendon-Bone Healing in an In Vitro Coculture Model

The effects of cyclooxygenase (COX) inhibition following the reconstruction of the anterior cruciate ligament remain unclear. We examined the effects of selective COX-2 and nonselective COX inhibition on bone-tendon integration in an in vitro model. We measured the dose-dependent effects of ibuprofen and parecoxib on the viability of lipopolysaccharide- (LPS-) stimulated and unstimulated mouse MC3T3-E1 and 3T3 cells, the influence on gene expression at the osteoblast, interface, and fibroblast regions measured by quantitative PCR, and cellular outgrowth assessed on histological sections. Ibuprofen led to a dose-dependent suppression of MC3T3 cell viability, while parecoxib reduced the viability of 3T3 cultures. Exposure to ibuprofen significantly suppressed expression of Alpl (P < 0.01), Bglap (P < 0.001), and Runx2 (P < 0.01), and although parecoxib reduced expression of Alpl (P < 0.001), Fmod (P < 0.001), and Runx2 (P < 0.01), the expression of Bglap was increased (P < 0.01). Microscopic analysis showed a reduction in cellular outgrowth in LPS-stimulated cultures following exposure to ibuprofen and parecoxib. Nonselective COX inhibition and the specific inhibition of COX-2 led to region-specific reductions in markers of calcification and cell viability. We suggest further in vitro and in vivo studies examining the biologic and biomechanical effects of selective and nonselective COX inhibition.

[Ligament bracing--augmented cruciate ligament sutures: biomechanical studies of a new treatment concept]

BACKGROUND

In the context of acute knee dislocations, suture repair of ruptured cruciate ligaments leads to good clinical results in 80% of cases. Disadvantages are low primary stability and subsequently secondary elongation of the sutured ligaments. In the present study, we compared primary stability of suture repair, reinforced by different suture augments, to cruciate ligament reconstruction.

OBJECTIVE

The concept of ligament bracing with transosseous suture repair of the cruciate ligaments and additional suture augmentation is biomechanically superior to cruciate ligament reconstruction.

MATERIAL AND METHODS

A total of 42 porcine knee joints divided into seven groups were examined. The stability of four different suture/augmentation combinations were compared to cruciate ligament reconstruction with human hamstring tendons. The investigational setup consisted of testing 1000 cycles with 20 N to 154 N load in a.-p. translation and 60° flexion. Elongation and load to failure were measured.

RESULTS

Neither reconstruction (3.13 ± 1.65 mm; 362 ± 51 N) nor augmented suture repair (1.89-2.5 mm; 464-624 N) achieved the primary stability of the intact cruciate ligament (0.63 ± 0.34 mm, 1012 ± 91 N). In comparison to ligament reconstruction, all four augmented suture repairs showed minor elongation in the cyclic test and a higher load to failure. The isolated suture repair showed poor results (6.79 ± 4.86 mm, 177 ± 73 N).

CONCLUSION

Augmented suture repair provides significantly higher stability compared with isolated suture repair and reconstruction with hamstring tendons. The concept of ligament bracing could be a promising future treatment option in acute knee dislocations. Clinical results remain to be seen.