Reduced platelet concentration does not harm PRP effectiveness for ACL repair in a porcine in vivo model

Enhanced primary repair of the ACL using a collagen scaffold loaded with platelets has been shown to improve the functional healing of suture repair in animal models. In this study, our objectives were to determine if lowering the platelet concentration would reduce the structural properties of the repaired ACL and increase postoperative knee laxity. Eight Yucatan mini‐pigs underwent bilateral suture repair. In one knee, the repair was augmented with a collagen scaffold saturated with platelet‐rich plasma (PRP) containing five times the systemic baseline of platelets (5×) while the contralateral knee had a collagen scaffold saturated with PRP containing three times the systemic baseline of platelets (3×). After 13 weeks of healing, knee joint laxity and the structural properties of the ACL were measured. The 3× platelet concentration resulted in a 24.1% decrease in cellular density of the repair tissue (p < 0.05), but did not significantly decrease the structural properties [3× vs. 5×: 362 N vs. 291 N (p = 0.242) and 70 N/mm vs. 53 N/mm (p = 0.189) for the yield load and linear stiffness, respectively]. The 3× platelet concentration also did not significantly change the mean anteroposterior knee laxity at 30° and 90° of flexion [5× vs. 3×: 3.5 mm vs. 5.1 mm (p = 0.140), and 6.1 mm vs. 6.3 mm (p = 0.764)] but did result in a lower AP laxity at 60° [5× vs. 3×: 8.6 mm vs. 7.3 mm (p = 0.012)]. The decrease in platelet concentration from 5× to 3× to enhance suture repair of the ACL did not significantly harm the mechanical outcomes in this animal model. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 1002–1007, 2011     

Platelet‐rich plasma alone is not sufficient to enhance suture repair of the ACL in skeletally immature animals: An in vivo study

In this study, we hypothesize that supplementation of suture repair of the anterior cruciate ligament (ACL) with platelet‐rich plasma (PRP) will improve the biomechanics of the repair. Six 30‐kg pigs underwent bilateral suture repair of the ACL. One side was treated with suture repair alone, while the contralateral side was treated with suture repair augmented with PRP. After 14 weeks in vivo, anterior–posterior (AP) knee laxity and the tensile properties of the repaired ligament were measured. The addition of PRP to the suture repairs did not improve AP knee laxity at 30° (p = 0.73) or 60° (p = 0.65). It also did not improve the maximum tensile load (p = 0.64) or linear stiffness (p = 0.42) of the ACL repairs after 14 weeks in vivo. The model had 80% power to detect a 30% improvement of biomechanical properties with PRP; thus, we are confident that a clinically meaningful effect as a result of adding PRP is unlikely. Use of PRP alone to supplement suture repair of the ACL is ineffective in this animal model. Published by Wiley Periodicals, Inc. J Orthop Res 27: 639–645, 2009     

Collagen scaffold supplementation does not improve the functional properties of the repaired anterior cruciate ligament

Primary suture anterior cruciate ligament (ACL) repair was abandoned in favor of reconstruction due to a high rate of clinical failures. However, the insertion of a collagen scaffold loaded with platelets into the wound at the time of suture repair (“enhanced primary repair”) has been shown to improve functional healing in animal models. Our objectives were to determine if using a collagen scaffold alone (without platelets) would be sufficient to increase the structural properties of the repaired ACL and decrease postoperative knee laxity compared to suture repair without the scaffold. Eight Yucatan minipigs underwent bilateral ACL transection and suture repair. In one knee, the repair was augmented with a collagen scaffold (SCAFFOLD group) while the other had suture alone (SUTURE group). After 13 weeks of healing, knee joint laxity and the structural properties of the ACL were measured. The addition of the collagen scaffold to suture repair of a transected ACL did not significantly improve the mean anteroposterior knee laxity [SCAFFOLD vs. SUTURE: 6.1 ± 1.4 vs. 4.4 ± 2.0 mm (p = 0.07), 8.1 ± 2.0 vs. 7.6 ± 2.0 mm (p = 0.66), and 6.2 ± 1.2 vs. 6.1 ± 1.8 mm (p = 0.85) at 30°, 60°, and 90° flexion, respectively]. Likewise, there were no significant differences in the structural properties [SCAFFOLD vs. SUTURE: 367 ± 185.9 vs. 322 ± 122.0N (p = 0.66) and 90.7 ± 29.5 vs. 85.0 ± 30.3N/mm (p = 0.74) for the yield load and linear stiffness, respectively]. The use of a collagen scaffold alone to enhance suture repair of the ACL was ineffective in this animal model. Future work will be directed at stimulating biological activity in the scaffold. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 28:703–709, 2010     

Cartilage Damage Is Related to ACL Stiffness in a Porcine Model of ACL Repair

Inferior anterior cruciate ligament (ACL) structural properties may inadequately restrain tibiofemoral joint motion following surgery, contributing to the increased risk of post‐traumatic osteoarthritis. Using both a direct measure of ACL linear stiffness and an in vivo magnetic resonance imaging (MRI) T₂*‐based prediction model, we hypothesized that cartilage damage and ACL stiffness would increase over time, and that an inverse relationship between cartilage damage and ACL stiffness would emerge at a later stage of healing. After either 6, 12, or 24 weeks (w) of healing after ACL repair, ACL linear stiffness was determined from the force–displacement relationship during tensile testing ex vivo and predicted in vivo from the MRI T₂*‐based multiple linear regression model in 24 Yucatan minipigs. Tibiofemoral cartilage was graded postmortem. There was no relationship between cartilage damage and ACL stiffness at 6 w (R² = 0.04; p = 0.65), 12 w (R² = 0.02; p = 0.77), or when the data from all animals were pooled (R² = 0.02; p = 0.47). A significant inverse relationship between cartilage damage and ACL stiffness based on both ex vivo measurement (R² = 0.90; p < 0.001) and in vivo MRI prediction (R² = 0.78; p = 0.004) of ACL stiffness emerged at 24 w. This result suggests that 90% of the variability in gross cartilage changes is associated with the repaired ACL linear stiffness at 6 months of healing. Clinical Significance: Techniques that provide a higher stiffness to the repaired ACL may be required to mitigate the post‐traumatic osteoarthritis commonly seen after ACL injury, and MRI T₂* can be used as a noninvasive estimation of ligament stiffness. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 37:2249–2257, 2019     

Quadrupled bone-semitendinosus ACL reconstruction: a prospective clinical investigation in 100 patients

Abstract The hypothesis of our study was that a quadrupled bonesemitendinosus tendon graft could combine the advantage of bone-tobone healing with the high cross-sectional area of a quadrupled hamstring graft in ACL reconstruction. ACL reconstruction with a semitendinosus tendon graft was performed on 100 patients with isolated ACL injury from January 1996 to December 1999: femoral fixation was obtained with Endobutton and tibial fixation with Fastlok. Patients were evaluated for standard knee scores and functional strength tests, postoperative pain rating, knee radiographs taken after surgery and at final follow-up, magnetic resonance images at 3 and 6 months, isokinetic flexion-extension and internal-external rotation tests at 3, 6, and 12 months. Computerized laxity analysis was performed at final evaluation. Average surgical time was 85 minutes, including 13 minutes for graft preparation; 90% of the patients were discharged within 24 h. Subjective knee rating was 80%; kneeling test was positive in 7% and Werner score was 44 (range, 30–48). Lachman test was negative in 90% at final evaluation (mean follow-up, 38 months). Sensory changes at the anterior part of the proximal tibia were present in 30% at 3 months and 10% had definite hyposthesia. MRI showed graft incorporation at 3 months. Computerized laxity analysis revealed 90% with less than 3-mm side-to-side differences. Isokinetic testing showed normal hamstring and quadriceps peak torques at 12 months. The functional strength tests were normal by 6 months. Average Noyes score was 87.9, Lysholm score 93, and Tegner activity rating 6.0 (pre-injury, 6.1). IKDC score showed 90 normal or nearly normal knees, 9 abnormal, and one severely abnormal knee. Quadrupled bone-semitendinosus is a viable graft for ACL reconstruction and should be considered, especially in patients with pre-existing extensor mechanism problems.     

Can suture repair of ACL transection restore normal anteroposterior laxity of the knee? An ex vivo study

Recent work has suggested the transected anterior cruciate ligament (ACL) can heal and support reasonable loads if repaired with sutures and a bioactive scaffold; however, use of a traditional suture configuration results in knees with increased anterior–posterior (AP) laxity. The objective was to determine whether one of five different suture repair constructs when performed at two different joint positions would restore normal AP knee laxity. AP laxity of the porcine knee at 60° of flexion was evaluated for five suture repair techniques. Femoral fixation for all repair techniques utilized a suture anchor. Primary repair was to either the tibial stump, one of three bony locations in the ACL footprint, or a hybrid bony fixation. All five repairs were tied with the knee in first 30° and then 60° of flexion for a total of 10 repair constructs. Suture repair to bony fixation points within the anterior half of the normal ACL footprint resulted in knee laxity values within 0.5 mm of the ACL‐intact joint when the sutures were tied with the knee at 60° flexion. Suture repair to the tibial stump, or with the knee at 30° of flexion, did not restore normal AP laxity of the knee. Three specific suture repair techniques for the transected porcine ACL restored the normal AP laxity of the knee at the time of surgery. Additional studies defining the changes in laxity with cyclic loading and in vivo healing are indicated. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 26:1500–1505, 2008     

T2* relaxometry and volume predict semi‐quantitative histological scoring of an ACL bridge‐enhanced primary repair in a porcine model

Magnetic resonance imaging (MRI) variables, such as T₂* and volume, can predict the healing ligament structural properties. How these MR variables relate to semi‐quantitative histology of the healing ACL is yet unknown. We hypothesized that T₂* and volume would predict the histological scoring of a healing ACL. Yucatan minipigs underwent ACL transection and received bridge‐enhanced ACL repair or no treatment. The surgical legs were harvested after 52 weeks and imaged using a high resolution 2‐echo sequence. For each ligament, the volume and median T₂* values were determined. The ACL specimens were then histologically analyzed using the advanced Ligament Maturity Index (LMI). The T₂* of the healing ligaments significantly predicted the total LMI score as well as the cell, collagen and vessel sub‐scores; R² = 0.78, 0.67, 0.65, and 0.60, respectively (p ≤ 0.001). The ligament volume also predicted the total LMI score, cell, and collagen sub‐scores; R² = 0.39, 0.33, 0.37, and 0.60, respectively (p ≤ 0.001). A lower ligament T₂* or a higher volume was associated with higher histological scores of the healing ligaments. This study provides a critical step in the development of a non‐invasive method to evaluate ligament healing on a microscopic scale. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1180–1187, 2015.     

Use of growth factors in ACL surgery: preliminary study

Abstract There is no general consensus on the use of growth factors (GF) in surgery. The aim of this study was to clarify if GF play a role in anterior cruciate ligament (ACL) surgery. Twenty patients with laxity caused by a torn ACL underwent arthroscopically assisted reconstruction with autologous hamstring tendons. We performed a prospective study with these patients randomized into 2 groups: GF-treated and control. Growth factors were obtained according to the GPS Biomet-Merck technique and are applied to femoral and tibial tunnels during surgical procedure. Patients were evaluated clinically and functionally. Computed tomography (CT) of the knee was performed in all the patients; a limited number of patients underwent magnetic resonance imaging (MRI). There were no significant differences concerning KOOS, IKDC, KT-1000, Tegner score rating and clinical examination between the two groups 6 months after ACL surgery. CT highlighted a significant difference (p<0.01) between ACL density of the two groups and showed that ACL density was similar to that of the posterior cruciate ligament in GF-treated group. In this group, however, one patient had a synovitic reaction: the new ACL was increased, hypertrophic and surrounded by a reaction of soft tissues. GF may accelerate the integration of the new ACL in the femoral and tibial tunnels, but further clinical studies are necessary to better understand the mechanism of action of GF, widely studied only in vitro and in animal models.     

Quantitative imaging of anterior cruciate ligament (ACL) graft demonstrates longitudinal compositional changes and relationships with clinical outcomes at 2 years after ACL reconstruction

T₁ρ and T₂ magnetic resonance imaging (MRI) may allow for a noninvasive assessment of ligamentization after anterior cruciate ligament (ACL) reconstruction. We hypothesized that ACL graft T₁ρ and T₂ relaxation times would decrease over time, that T₁ρ and T₂ relaxation times would be inversely correlated with Knee Osteoarthritis Outcome Scores (KOOS), and that T₁ρ and T₂ values would be lower for autograft relative to allograft reconstruction. Thirty-nine patients (age: 30.5 ± 8.2 years) were followed prospectively after ACL reconstruction with hamstring autograft (N = 27) or soft-tissue allograft (N = 12). Magnetic resonance (MR) imaging and KOOS surveys were completed at 6, 12, 24, and 36 months after surgery. ACL graft was segmented to define T₁ρ and T₂ relaxation times. Relaxation times were compared between time points with ANOVA tests. Log-transformed autograft and allograft relaxation times were compared with the Student t tests. The relationship between KOOS and relaxation times at 24 months was investigated with Spearman's rank correlation. ACL graft T₁ρ relaxation times were significantly higher at 6 months relative to 12 months (P = .042), 24 months (P < .001), and 36 months (P < .001). ACL graft T₂ relaxation times were significantly higher at 6 months relative to 12 months (P = .036), 24 months (P < .001), and 36 months (P < .001). T₁ρ and T₂ relaxation times were significantly lower for autograft reconstruction vs allograft reconstruction at 24 months postreconstruction. Two-year KOOS Sports, Pain, and Symptoms were significantly inversely correlated with T₁ρ and T₂ relaxation times. T₁ρ and T₂ sequences may offer a noninvasive method for monitoring ACL graft maturation that correlates with patient-reported knee function after ACL reconstruction.     

Effects of reinforcement with the iliotibial tract flap in ACL reconstruction using bone-patellar tendon-bone

Introduction We attempted to reinforce the transplanted ligament by wrapping it with the iliotibial tract (ITT) flap to get more volume and to protect the graft from impingement in the intercondylar space postoperatively in reconstruction of the anterior cruciate ligament (ACL) using bone-patellar tendon-bone (BTB), and investigated the results in comparison with those of BTB alone.Materials and methods The study included 88 cases (88 knees). Group A comprised 43 knees with the reinforcement and group B 45 knees with BTB alone. Both groups were evaluated by second-look arthroscopy, magnetic resonance imaging (MRI), manual testing, International Knee Documentation Committee (IKDC) score, and histopathological evaluation more than 2 years after the reconstruction.Results In the second-look arthroscopic findings, 84% of the reconstructed ACL in group A had good appearance, and no fibrous split was observed. The ratio of fibrous disorder was significantly less in group A in comparison with group B (p=0.0037). Distinct reduction of the tension of the reconstructed ligament was observed in 9% of group A and 36% of group B (p=0.0088). Regarding the results of the Lachman test, the ratio of the negative group was higher in group A (p=0.0067). In the MRI findings fulfilled pictures to the inside of the reconstructed ligament were observed in 77% of the patients photographed in group A. In contrast, the fibrous split was observed in 55% in group B.Conclusions Reinforcement by wrapping with the ITT flap for the BTB autograft was effective in ACL reconstruction. The ratio of fibrous disorder and reduction of tension in the reconstructed ligament decreased.     

Anatomical Reconstruction of the Anterior Cruciate Ligament in Goats

A surgical procedure was developed for the implantation of an anatomical, two-banded anterior cruciate ligament (ACL) prosthesis. Prostheses were fabricated of braided long-chain polyethylene fibers. The left ACL of adult male goats was surgically excised and replaced with either an anatomical reconstruction (5 goats) or a conventional reconstruction (5 goats). The anatomical reconstruction required drilling four bone tunnels, two each in the femur and tibia. Each band of the prosthesis was placed through one tunnel in the femur and the corresponding tunnel in the tibia, recreating the anteromedial and posterolateral bands. The two bands were tensioned independently and stapled in place. In the conventional procedure, the prosthesis was doubled and placed through two larger tunnels, one in the femur and one in the tibia, tensioned and stapled together. All animals were terminated 3 months after surgery. Clinical evaluation of passive range of motion, anlero-poslerior laxity and the appearance of the joint space showed little or no difference between the reconstruction methods. The ultimate failure load for the natural (unoperated) ACL was 1691 ± 210 N, while the anatomical and conventional reconstruction groups had mean ultimate failure loads of 1233 ± 732 and 1012 ± 220 N, respectively. The elongation to failure of all groups was similar: the natural ACL group = 7.1 ± 2.8 mm, the anatomical group = 7.2 ± 2.9 mm, and the conventional group = 7.7 ± 3.9 mm. The slope of the load-deformation curve, or stiffness, was significantly higher for the natural ACL (4.53 ± 1.24 × 10⁵ N/m) than for either of the reconstruction methods (2.75 ± 1.59 × 10⁵ N/m for the anatomical and 2.34 ± 0.60 × 10⁵ N/m for the conventional). The energy to failure, or area under the load-deformation curve, showed no significant difference between groups. In conclusion, both types of reconstructions were less strong, stiff, and tough than the natural ACL. There was no significant difference observed between the anatomical and conventional reconstruction methods over the 3-month implantation time in either clinical evaluation or mechanical testing. Therefore, at 3 months postsurgery, the anatomical reconstruction technique was considered no better and no worse than the conventional reconstruction technique     

Osteoarthritis develops in the operated joint of an ovine model following ACL reconstruction with immediate anatomic reattachment of the native ACL

We tested the hypothesis that immediate reattachment of the native anterior cruciate ligament (ACL) can prevent kinematic changes and the development of osteoarthritis (OA). Five sheep underwent anatomic unilateral ACL reconstruction (ACL‐R). Animals from a previous study served as sham (n = 7) or non‐operated (n = 17) controls. At 4 points of walking gait, 6 degrees of freedom stifle joint kinematics of ACL‐R animals were compared with sham controls at 4 and 20 weeks post‐surgery. Gross cartilage, bone, and meniscal changes were graded at euthanasia; paired and differential scores were compared. Inter‐animal differences were noted in all groups. Of 48 points of gait comparison between ACL‐R and sham operated groups, 42 points showed no difference (p > 0.05). Of the six significant differences (p < 0.05), internal rotation in ACL‐R animals accounted for three. At 20 weeks, differential scores showed that sham operated joints were morphologically indistinguishable from non‐operated controls (p ≥ 0.129) while ACL‐R joints had significantly higher combined cartilage and osteophyte scores than those controls (p ≤ 0.003). This method of ACL reconstruction in sheep did not restore normal walking gait kinematics completely and allowed some OA to develop in operated joints. OA may result from relatively subtle mechanical abnormalities, apparently more so in some individuals than others. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 31:35–43, 2012     

Perturbation training prior to ACL reconstruction improves gait asymmetries in non-copers

We investigated whether preoperative perturbation training would help anterior cruciate ligament (ACL) deficient individuals who complain of knee instability (“non-copers”) regain quadriceps strength and walk normally after ACL reconstruction. Nineteen non-copers with acute ACL injury were randomly assigned into a perturbation group (PERT) or a strengthening group (STR). The PERT group received specialized neuromuscular training and progressive quadriceps strength training, whereas the STR group received progressive quadriceps strength training only. We compared quadriceps strength indexes and knee excursions during the mid-stance phase of gait preoperatively to data collected 6 months after ACL reconstruction. Analyses of Variance with repeated measures (time/limb) were conducted to compare quadriceps strength index values over time (time × group) and differences in knee excursions in limbs between groups over time (limb × time × group). If significance was found, post hoc analyses were performed using paired and independent t-tests. Quadriceps strength indexes before intervention (Pert: 87.2%; Str: 75.8%) improved 6 months after ACL reconstruction in both groups (Pert: 97.1%; Str: 94.4%). Non-copers who received perturbation training preoperatively had no differences in knee excursions between their limbs 6 months after ACL reconstruction (p = 0.14), whereas those who received just strength training continued to have smaller knee excursions during the mid-stance phase of gait (p = 0.007). Non-copers strength and knee excursions were more symmetrical 6 months postoperatively in the group that received perturbation training and progressive quadriceps strength training than the group who received strength training alone. © 2008 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 27: 724–729, 2009     

Anatomic variations between Japanese and Caucasian populations in the healthy young adult knee joint

Our objective was to characterize variations in mechanical knee alignment, tibial torsion, tibial width, and ACL laxity measurements between Japanese and Caucasian populations in the healthy, young adult knee joint. Seventy young adult subjects participated in this study, including 23 Japanese and 47 Caucasian subjects. Coronal magnetic resonance images of the hip, knee, and ankle were acquired for analysis. Japanese subjects had a significantly higher (p = 0.04) varus alignment (1.64 ± 0.43° standard error) than Caucasians (0.55 ± 0.33°), while women exhibited a more valgus alignment (0.16 ± 0.52°) than men (0.94 ± 0.42°, p = 0.04). Significant differences were found in tibial torsion and ACL laxity (p < 0.01) between ethnicities, with Japanese exhibiting lower tibial torsion (33.4 ± 10.0°) and higher ACL laxity (7.5 ± 0.4 mm) measurements compared to Caucasians (38.9 ± 9.5° and 5.7 ± 0.3 mm, respectively). Significant differences between genders were found in hip‐knee‐ankle alignment (p = 0.04), tibial width (p < 0.0001), and ACL laxity (p < 0.01) measurements. Measurements were reliable between observers and for repeated positioning. Our study provides new insight into anatomical and geometric differences in the knee joint between Japanese and Caucasians, as well as between females and males. Further consideration of these results may improve development of implants to accommodate for these differences, and understanding of characteristics leading to increased prevalence of knee OA in certain populations. The use of magnetic resonance imaging to obtain these measurements also allows soft tissue structure characterization without exposure to ionizing radiation. © 2009 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res     

Age,sex, body anthropometry,and ACL size predict the structural properties of the human anterior cruciate ligament

Anterior cruciate ligament (ACL) injury continues to be at the forefront of sports injury concerns because of its impact on quality of life and joint health prognosis. One strategy is to reduce the occurrence of this injury by identifying at‐risk subjects based on key putative risk factors. The purpose of our study was to develop models that predict the structural properties of a subject's ACL based on the combination of known risk factors. We hypothesized that the structural properties of the ACL can be predicted using a multi‐linear regression model based on significant covariates that are associated with increased risk of injury, including age, sex, body size, and ACL size. We also hypothesized that ACL size is a significant contributor to the model. The developed models had predictive capabilities for the structural properties of the ACL: load at failure (R² = 0.914), elongation at failure (R² = 0.872), energy at failure (R² = 0.913), and linear stiffness (R² = 0.756). Furthermore, sex, age, body mass, BMI, and height were contributors (p < 0.05) to all predicted structural properties. ACL minimal area was a contributor to elongation, energy at failure, and linear stiffness (p < 0.05), but not to load at failure. ACL volume was also a contributor to elongation and energy at failure (p < 0.05), but not to linear stiffness and load at failure models. ACL length was not a significant contributor to any structural property. The clinical significance of this research is its potential, after continued development and refinement of the model, for application to prognostic studies that are designed to identify individuals at increased risk for injury to the ligament. © 2011 Orthopaedic Research Society Published by Wiley Periodicals, Inc. J Orthop Res 29: 993–1001, 2011     

Comparison of patellar tendon versus hamstrings autografts for anterior cruciate ligament reconstruction in Indian population: A randomised control trial study

Disruption of anterior cruciate ligament (ACL) is a common ligamentous injury of the knee. The best choice of graft for reconstruction remains undecided. This prospective, randomized clinical trial aimed to compare clinical results of bone-patellar tendon-bone (BPTB) grafts and four-strand semitendinosus-gracilis (QHT) grafts for ACL reconstruction over a 1-year follow-up interval in Indian population.Methods42 consecutive patients with ACL injury were recruited, by pick and draw method and allotted into two groups with 21 patients in each group. Group A patients underwent arthroscopic ACL reconstruction using BPTB graft while QHT autograft was used for patients in Group B. All the patients underwent standard ipsilateral arthroscopic ACL reconstruction procedure using a single incision, antero-medial (AM) portal technique for BPTB or the QHT autograft by a same surgeon. Patients were followed up regularly for a minimum period of 1 year.ResultsAfter one year, the Cincinnati score was 91 ± 4.117 in BPTB group and 89.29 ± 5.371 in QHT group (P = 0.282). There was no significant difference between the two groups in the mean scores with respect to pain, overall activity level and running in the Cincinnati score. None of the patients complained of the knee giving way. Similarly, at 1 year, the Lysholm score was 92.84 ± 2.630 and 90.55 ± 2.395 in the two groups respectively (P = 0.842). There were no episodes of locking or instability and there was no significant difference in the mean Lysholm scores regarding pain and squatting.ConclusionThere was no significant functional difference between the two grafts in terms of Lysholm and the Cincinnati score, anterior knee laxity and altered sensation over proximal leg. The patients with QHT groups performed better than BPTB functionally at 6 month so early return to sport is possible even with QHT autograft.     

Evaluation of sex differences in rodent anterior cruciate ligament injury

The relative contributions of sex differences in anatomy, biomechanics, and hormones to the increased risk of anterior cruciate ligament (ACL) injury in female athletes remains unknown. The purpose of this study is to investigate sex differences in anatomy and biomechanics of the native and reconstructed ACL using our established murine model. A total of 140 12-week-old wild-type C57Bl/6 (70 male vs. 70 female) mice were used for this study. ACL reconstruction was performed on 120 mice who were split into four groups: Group 1 (30 males sacrificed at 14 days), Group 2 (30 females sacrificed at 14 days), Group 3 (30 males sacrificed at 28 days), and Group 4 (30 females sacrificed at 28 days). Tendon graft-to-bone healing was assessed by biomechanical, histological, and micro-CT analysis. Twenty mice were used for baseline testing. Females showed significantly higher anterior (p < 0.05) and total displacement (p < 0.05). Males demonstrated a significantly higher load-to-failure force of native ACLs compared to females (p < 0.05). There was no significant difference in load-to-failure force in the ACL autograft. There were no significant sex differences in histological analysis of graft integration or tibial slope. The increased knee laxity and reduced load-to-failure of the native ACL observed in the female mice are consistent with some of the proposed risk factors driving the increased risk of ACL injury in females. Understanding the relative contributions of factors driving sex differences in material properties of the ACL will provide insight into the sex differences in ACL injury and future prevention strategies.     

Psychosocial factors 3-months after anterior cruciate ligament reconstruction predict 6-month subjective and objective knee outcomes

The objective of the study was to determine if psychological readiness for sport and knee self-efficacy assessed early (3 months) after anterior cruciate ligament reconstruction (ACLR) are predictive of self-reported functional outcomes, quadriceps strength, and knee mechanics while running at the time of return to sport training (6 months). Thirty athletes with unilateral ACLR completed the ACL Return to Sport after Injury (ACL-RSI) and Knee Self-Efficacy Scale (K-SES) 3 months after ACLR and completed self-reported functional outcomes, isometric quadriceps strength testing, and three-dimensional running gait analysis 6 months after ACLR. The 3-month ACL-RSI significantly correlated with the 6-month International Knee Documentation Committee (IKDC; r = 0.565, p = 0.001), Knee Injury and Osteoarthritis Outcome Score (KOOS) sport/recreational activities (KOOS_Sport; r = 0.548, p = 0.002) and quality of life (KOOS_QoL; r = 0.431, p = 0.017), and quadriceps strength (r = 0.528, p = 0.003). The 3-month K-SES significantly correlated with the 6-month IKDC (r = 0.528, p = 0.003), KOOS_Sport (r = 0.430, p = 0.018), KOOS_QoL (r = 0.411, p = 0.024), quadriceps strength (r = 0.465, p = 0.010), and knee flexion excursion (r = 0.472, p = 0.008). With multivariate modeling, both the ACL-RSI and K-SES were predictive of the IKDC (R² = 0.411; p = 0.001). Only the ACL-RSI was predictive of the KOOS_Sport (R² = 0.300; p = 0.002), KOOS_QoL (R² = 0.186; p = 0.017), and quadriceps strength (R² = 0.279; p = 0.003), whereas only the K-SES was predictive of knee flexion excursion (R² = 0.173; p = 0.022). Athletes with greater psychological readiness for sport and knee self-efficacy at 3 months demonstrated higher scores on self-reported functional outcomes, greater quadriceps strength, and greater knee flexion excursion at 6 months after ACLR. This study indicates that psychosocial measures may be important to include into early post-surgical evaluations to help guide and facilitate interventions to restore subjective and objective knee function.     

Knee extension torque variability after exercise in ACL reconstructed knees

The purpose of this study was to compare knee extension torque variability in patients with ACL reconstructed knees before and after exercise. Thirty two patients with an ACL reconstructed knee (ACL‐R group) and 32 healthy controls (control group) completed measures of maximal isometric knee extension torque (90° flexion) at baseline and following a 30‐min exercise protocol (post‐exercise). Exercise included 30‐min of repeated cycles of inclined treadmill walking and hopping tasks. Dependent variables were the coefficient of variation (CV) and raw‐change in CV (ΔCV): CV = (torque standard deviation/torque mean x 100), ΔCV = (post‐exercise – baseline). There was a group‐by‐time interaction (p = 0.03) on CV. The ACL‐R group demonstrated greater CV than the control group at baseline (ACL‐R = 1.07 ± 0.55, control = 0.79 ± 0.42, p = 0.03) and post‐exercise (ACL‐R = 1.60 ± 0.91, control = 0.94 ± 0.41, p = 0.001). ΔCV was greater (p = 0.03) in the ACL‐R group (0.52 ± 0.82) than control group (0.15 ± 0.46). CV significantly increased from baseline to post‐exercise (p = 0.001) in the ACL‐R group, while the control group did not (p = 0.06). The ACL‐R group demonstrated greater knee extension torque variability than the control group. Exercise increased torque variability more in the ACL‐R group than control group. © 2015 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 33:1165–1170, 2015.     

Anterior cruciate ligament reconstruction and physiological joint laxity: earliest changes in joint stability and stiffness after reconstruction

Physiological joint laxity is an important element of normal knee joint function, providing smooth joint movement. However, the objective evaluation of post-operative results after knee ligament surgery is usually based primarily on stability and range of motion, and joint laxity has been ignored. In this study, we measured the joint stiffness of 82 knees undergoing anterior cruciate ligament (ACL) reconstruction with the Leeds-Keio artificial ligament, before the operation, immediately after the operation, and finally when the full range of motion was achieved postoperatively; changes in joint laxity after the ACL reconstruction were investigated. Before the operation, joint laxity was greater than that of the normal side (P < 0.01), but immediately after the operation it diminished compared not only with that observed preoperatively, but also with that of the normal side. When the full range of motion was achieved, joint laxity was lower than that observed immediately after the operation (P < 0.01), but still remained higher than that of the normal side (P < 0.01). In other words, stability was achieved, but joint laxity was diminished through the operation. In this series, a stiffer artificial ligament than the natural ACL was used, and maximum tension was applied during the operation, aiming at better stability, but this may cause diminution of joint laxity. Received for publication on Sept. 1998; accepted on Dec. 2, 1998