Donor age has no relevant role in biomechanical properties of allografts used in anterior cruciate ligament (ACL) reconstruction: A systematic review.

PURPOSE: Surgeons generally consider the donor age as a factor that negatively influences the quality of allograft used in anterior cruciate ligament (ACL) reconstruction, however, the available evidence does not clearly support this statement. The purpose of the study was to investigate if donor age influences the biomechanical properties of allografts used in ACL reconstruction. METHODS: A comprehensive literature search was conducted for all relevant articles using MEDLINE (PubMed), Scopus, and Cochrane Collaboration Library, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Studies including the analysis of the correlation between biomechanical properties of the allografts and donor age were selected. The role of donor age was labelled as 'none' if absent, 'higher' or 'lower' if the properties were higher or lower in older specimens with respect to younger. The correlation was defined as 'weak' or 'strong' according to each study definition. RESULTS: No conflicting role of donor age was reported for modulus of elasticity, load to failure, strain, stiffness and displacement. The only parameters where the significant results were consistent were the tensile strength and the stress (low or moderate correlations). When considering the tested samples with a donor's age <65 years, a significant role of age was reported in only four out of 13 groups of graft tested (patellar tendon, fascia lata, anterior tibialis tendon and posterior tibialis tendon). CONCLUSION: The current literature did not allow to state that the donor age negatively influences the biomechanical properties of allografts, making it impossible to identify a clear age cut-off value to exclude them from ACL reconstruction procedures. LEVEL OF EVIDENCE: Level IV, systematic review.

Kinematics of 90° change of direction in young football players: Insights for ACL injury prevention from the CUTtheACL study on 6008 trials.

PURPOSE: To investigate the 90° change of direction (COD) task in an extensive cohort of competitive healthy football players within the CUTtheACL study and to provide normative values and differences between males and females for full-body kinematics based on two-dimensional (2D) video analysis and scoring system. METHODS: One-thousand-and-two competitive football (soccer) players (age 16.3 ± 2.8 years, 264 females) were prospectively enroled. Each player performed three preplanned 90° COD tasks per limb. The 2D evaluation was performed through objective measures (collected through three high-speed cameras) of frontal and sagittal plane joint kinematics at the cut initial foot contact (IC) and maximum knee flexion angle. A previously published scoring system was adopted to measure the movement quality of the COD task. The scoring system included five criteria (limb stability [LS], pelvis stability [PS], trunk stability [TS], shock absorption [SA], movement strategy [MS]) ranked from 0/2 (nonadequate) to 2/2 (adequate) with a maximum score of 10/10. Normative data were provided for all the variables; statistical differences between male and female players were investigated (p < 0.05). RESULTS: A total of 6008 valid attempts were included. Frontal plane knee projection angle (FPKPA) at initial contact was 24.4 ± 9.8° (95th percentile: FPKPA > 40°). The total score was ≤4/10 in 71.2% of the trials, the lowest subscores were LS and PS. Female players showed different movement patterns with lower hip and trunk flexion both at IC and maximum knee flexion angle (p < 0.01, ES = 0.41-0.64). Female players also showed worse scores than males in SA, MS and total score (p < 0.01). CONCLUSION: Female players seem more prone to stiffer lower limb strategy and greater pelvis-trunk frontal plane instability than males. Clinicians could adopt normative data and sex-specific differences in players' movement techniques to improve ACL injury risk mitigation protocols. LEVEL OF EVIDENCE: Level IV.

Application of Machine Learning Methods to Investigate Joint Load in Agility on the Football Field: Creating the Model, Part I.

Laboratory studies have limitations in screening for anterior cruciate ligament (ACL) injury risk due to their lack of ecological validity. Machine learning (ML) methods coupled with wearable sensors are state-of-art approaches for joint load estimation outside the laboratory in athletic tasks. The aim of this study was to investigate ML approaches in predicting knee joint loading during sport-specific agility tasks. We explored the possibility of predicting high and low knee abduction moments (KAMs) from kinematic data collected in a laboratory setting through wearable sensors and of predicting the actual KAM from kinematics. Xsens MVN Analyze and Vicon motion analysis, together with Bertec force plates, were used. Talented female football (soccer) players (n = 32, age 14.8 ± 1.0 y, height 167.9 ± 5.1 cm, mass 57.5 ± 8.0 kg) performed unanticipated sidestep cutting movements (number of trials analyzed = 1105). According to the findings of this technical note, classification models that aim to identify the players exhibiting high or low KAM are preferable to the ones that aim to predict the actual peak KAM magnitude. The possibility of classifying high versus low KAMs during agility with good approximation (AUC 0.81-0.85) represents a step towards testing in an ecologically valid environment.

Wider translations and rotations in posterior-stabilised mobile-bearing total knee arthroplasty compared to fixed-bearing both implanted with mechanical alignment: a dynamic RSA study.

PURPOSE: The purpose of this study was to investigate the in vivo kinematics of the same femoral design mechanically aligned posterior-stabilised (PS) total knee arthroplasty (TKA) with either fixed-bearing (FB) or mobile-bearing (MB) inlay, implanted by the same surgeon, using model-based dynamic radiostereometric analysis (RSA). The hypothesis of the present study was that the MB design would show wider axial rotation than the FB design, without affecting the clinical outcomes. MATERIALS AND METHODS: A cohort of 21 non-randomised patients (21 DePuy Attune PS-FB) was evaluated by dynamic RSA analysis at a minimum 9-month follow-up, while performing differently demanding daily living activities such as sit to stand (STS) and deep knee lunge (DKL). Kinematic data were compared with those of a cohort of 22 patients implanted with the same prosthetic design but with MB inlay. Anterior-posterior (AP) translations, varus-valgus (VV) and internal-external (IE) rotations of the femoral component with respect to the tibial baseplate were investigated. Translation of medial and lateral compartment was analysed using the low point method according to Freeman et al. Questionnaires to calculate objective and subjective clinical scores were administered preoperatively and during follow-up visit by the same investigator. RESULTS: The FB TKA design showed lower AP translation during STS (6.8 ± 3.3 mm in FB vs 9.9 ± 3.7 mm in MB, p = 0.006*), lower VV rotation (1.9 ± 0.8° in FB vs 5.3 ± 3.3° in MB, p = 0.005) and lower IE rotation (2.8 ± 1.1° in FB vs 9.5 ± 4.3° in MB, p = 0.001) during DKL than the mobile-bearing TKA design. Posterior-stabilised FB group showed significant lower translation of the low point of the medial compartment than the MB group (p = 0.008). The percentage of patients performing medial pivot in the FB group was higher compared to MB group in the examined motor tasks. No significant differences in post-operative range of motion (117° ± 16° for FB group and 124° ± 13° for MB group) and in clinical outcomes emerged between the two cohort. CONCLUSIONS: The FB and MB designs differed in AP translations, VV rotations and IE rotations of the femoral component with respect to the tibial component in STS and DKL. Furthermore, FB cohort reported a significant higher percentage of medial pivot with respect to MB cohort. Despite this, no differences in clinical outcomes were detected between groups. Both designs showed stable kinematics and represent a viable option in primary TKA. LEVEL OF EVIDENCE: Prospective cohort study, II.

Good long-term patients reported outcomes, return-to-work and return-to-sport rate and survivorship after posterior cruciate ligament (PCL)-based multiligament knee injuries (MLKI) with posteromedial corner tears as significant risk factor for failure.

PURPOSE: To assess the survival rate and associated risk factors of a wide cohort of patient's underwent surgical treatment for posterior cruciate ligament (PCL)-based multiligament knee injury (MLKI) at long-term follow-up and to investigate the long-term patient's reported outcomes (PROMS) and functional activity. METHODS: All cases of PCL-based MLKI performed at one single sport-medicine institution were extracted and patient's with a minimum 2 years of follow-up included. VAS, Lysholm, KOOS, Tegner Activity level scores, the incidence and time of return to sport (RTS) and return to work (RTW) were collected before, after surgery and at final follow-up. A multivariate logistic regression was performed to investigate the outcomes associated with the patient's acceptable symptoms state (PASS) for each sub-score of the KOOS. The Kaplan-Meier method with surgical failure (re-operation to one of the reconstructed ligaments) as endpoint was used to perform the survivorship analysis for the entire cohort. RESULTS: Forty-two patients were included and evaluated at an average of 10 years. All PROMS significantly improved from pre- to post-surgery (range ηp2 0.21-0.43, p < 0.05) except for the Tegner score which significantly improved from pre-surgery and to final follow-up (ηp2 = 0.67, p < 0.001). RTW was achieved in the 95.2% after 2.4 ± 1.9 months. RTS was achieved in 78.6% after 6.7 ± 5.0 months. The higher number of surgeries were the significant negative predictors of PASS for the KOOS sub-scales Sport (p = 0.040) and Quality of Life (p = 0.046), while the presence of meniscal lesions was a significant negative predictor of PASS only for the KOOS sub-scale of Sport (p = 0.003). Six patients (14.3%) underwent reoperation and were considered as surgical failures. The global survivorship was 95.2%, 92.6%, 87.1%, and 74.7% at 2, 5, 12, and 15 years, respectively. The survivorship in patient undergoing PMC reconstruction surgery was significantly lower (p = 0.004; HR 7.1) compared to patients without a PMC lesion. CONCLUSION: Good-to-excellent PROMS could be obtained and maintained at long-term follow-up after surgery, with the higher number of surgeries and meniscal lesions as significant negative predictors of the PASS. Moreover, the presence of a PMC lesion significantly increases the risk of the PCL reconstruction failure. LEVEL OF EVIDENCE: III.

Satisfactory long-term outcomes for combined anterior cruciate ligament reconstruction and lateral closing wedge high tibial osteotomy.

PURPOSE: A combined anterior cruciate ligament (ACL) reconstruction and high tibial osteotomy (HTO) is considered a valuable treatment in young patients affected by symptomatic medial osteoarthritis and ACL deficiency. However, only a few studies have investigated the outcomes of this procedure, especially in the long term. Therefore, the aim of this study is to report clinical and radiographic outcomes of ACL reconstruction and lateral closing wedge HTO at a mean of 14 years of follow-up. METHODS: Patients were prospectively evaluated pre-operatively, after 6.5 ± 2.7 years and 14.3 ± 2.2 years. Patient-reported outcome measures (PROMs) were collected, knee laxity was assessed through KT-1000 arthrometer, and limb alignment and knee osteoarthritis were evaluated on long-cassette radiographs. Survivorship of the surgical procedure was calculated through the Kaplan-Meier method. RESULTS: 32 patients were initially enrolled and completed the mid-term evaluation (6.5 ± 2.7 years), and 23 patients (72%) were available for the final evaluation at 14.3 ± 2.2 years after surgery. Statistically significant improvement was found for all the clinical scores (VAS, WOMAC, Tegner, subjective IKDC, objective IKDC) between the pre-operative status and the mid-term follow-up (p < .001). VAS, subjective IKDC and objective IKDC showed no statistically significant differences (p > .05) between the mid-term and the final follow-up; a significant decrease of WOMAC (p < .05) and Tegner (p < .001) was found from mid-term to final follow-up. Significant progression of osteoarthritis was found for all the knee compartments. The survivorship was 95.7% at 5 years, 82.6% at 10 years, and 72.8% at 15 years. CONCLUSIONS: Combined ACL reconstruction and lateral closing wedge HTO showed satisfactory clinical outcomes and survivorship at a mean of 14 years follow-up. LEVEL OF EVIDENCE: IV.

No difference in patient reported outcomes, laxity, and failure rate after revision ACL reconstruction with quadriceps tendon compared to hamstring tendon graft: a systematic review and meta-analysis.

PURPOSE: The purpose of this study was to synthesize and quantitatively assess the outcomes of ACL Revision using a quadriceps tendon (QT) graft and to compare them with those of ACL Revisions performed with hamstring tendons (HT) graft. METHODS: A comprehensive search based on the PRISMA protocol was performed across PubMed, Scopus, Embase, and Cochrane Library from inception until February 2022. Clinical studies reporting the outcomes of ACL Revision with QT autograft were included. Subjective and Objective IKDC, Tegner activity level, Lysholm knee score, KOOS score, VAS for pain, knee laxity (KT-1000/2000 arthrometer, Lachman test, and pivot-shift test), and graft failure were assessed. A systematic review and meta-analysis were performed and a quality assessment of the included studies was carried out with the MINORS score. RESULTS: Seven studies met the selection criteria and were included in the systematic review for the qualitative synthesis of data. A pooled mean of all the variables was provided for the 7 studies, while 3 studies included a control group of ACL Revision with HT and were included in a meta-analysis. A total of 420 participants with a mean age of 28.9 ± 10.5 years and a mean postoperative follow-up of 39.3 ± 16.4 months were assessed. Of these, 277 patients underwent ACL Revision with QT and 143 patients underwent ACL Revision with HT. In the QT group, average graft failure was 9.8% compared to 17.4% in the HT group. KOOS Sport and pivot-shift test showed better postoperative outcomes in QT than HT, although it was not statistically significant (p = 0.052). CONCLUSION: The QT autograft was associated with an improved trend of rotatory laxity, PROMs and failure rate compared to HT autograft after revision ACL reconstruction. The QT autograft for revision ACL reconstruction is supported by the current literature. It is a viable graft that should be considered for both primary and revision ACL reconstruction. LEVEL OF EVIDENCE: Level IV.

Definition of High-Risk Motion Patterns for Female ACL Injury Based on Football-Specific Field Data: A Wearable Sensors Plus Data Mining Approach.

The aim of the present study was to investigate if the presence of anterior cruciate ligament (ACL) injury risk factors depicted in the laboratory would reflect at-risk patterns in football-specific field data. Twenty-four female footballers (14.9 ± 0.9 year) performed unanticipated cutting maneuvers in a laboratory setting and on the football pitch during football-specific exercises (F-EX) and games (F-GAME). Knee joint moments were collected in the laboratory and grouped using hierarchical agglomerative clustering. The clusters were used to investigate the kinematics collected on field through wearable sensors. Three clusters emerged: Cluster 1 presented the lowest knee moments; Cluster 2 presented high knee extension but low knee abduction and rotation moments; Cluster 3 presented the highest knee abduction, extension, and external rotation moments. In F-EX, greater knee abduction angles were found in Cluster 2 and 3 compared to Cluster 1 (p = 0.007). Cluster 2 showed the lowest knee and hip flexion angles (p < 0.013). Cluster 3 showed the greatest hip external rotation angles (p = 0.006). In F-GAME, Cluster 3 presented the greatest knee external rotation and lowest knee flexion angles (p = 0.003). Clinically relevant differences towards ACL injury identified in the laboratory reflected at-risk patterns only in part when cutting on the field: in the field, low-risk players exhibited similar kinematic patterns as the high-risk players. Therefore, in-lab injury risk screening may lack ecological validity.

Longitudinal Gait Analysis of a Transfemoral Amputee Patient: Single-Case Report from Socket-Type to Osseointegrated Prosthesis.

The aim of the present case report was to provide a longitudinal functional assessment of a patient with transfemoral amputation from the preoperative status with socket-type prosthesis to one year after the osseointegration surgery. A 44 years-old male patient was scheduled for osseointegration surgery 17 years after transfemoral amputation. Gait analysis was performed through 15 wearable inertial sensors (MTw Awinda, Xsens) before surgery (patient wearing his standard socket-type prosthesis) and at 3-, 6-, and 12-month follow-ups after osseointegration. ANOVA in Statistical Parametric Mapping was used to assess the changes in amputee and sound limb hip and pelvis kinematics. The gait symmetry index progressively improved from the pre-op with socket-type (1.14) to the last follow-up (1.04). Step width after osseointegration surgery was half of the pre-op. Hip flexion-extension range significantly improved at follow-ups while frontal and transverse plane rotations decreased (p < 0.001). Pelvis anteversion, obliquity, and rotation also decreased over time (p < 0.001). Spatiotemporal and gait kinematics improved after osseointegration surgery. One year after surgery, symmetry indices were close to non-pathological gait and gait compensation was sensibly decreased. From a functional point of view, osseointegration surgery could be a valid solution in patients with transfemoral amputation facing issues with traditional socket-type prosthesis.

No kinematical difference between ultra-congruent and medial-congruent total knee arthroplasty when implanted with mechanical alignment: an in vivo dynamic RSA study.

PURPOSE: To explore in vivo kinematical behavior of the same total knee arthroplasty (TKA) cruciate-retaining (CR) femoral design with either medial-congruent (MC) or ultra-congruent (UC) inlay using model-based dynamic radiostereometric analysis (RSA). The hypothesis was that there would be comparable kinematics between the two groups. METHODS: A cohort of 16 randomly selected patients (8 MC Persona Zimmer, 8 UC Persona Zimmer) was evaluated through dynamic radiostereometric analysis (RSA) at a minimum of 9 months after TKA, during the execution of a sit-to-stand. The antero-posterior (AP) translation of the femoral component and the AP translation of the low point of medial and lateral femoral compartments were compared through Student's t test (p < 0.05). RESULTS: Both groups showed a medial pivot behavior, with a significantly greater anterior translation of the Low Point of the lateral compartment with respect to the medial compartment (MC medial range: 2.4 ± 2.4 mm; MC lateral range: 7.7 ± 3.0 mm; p < 0.001 - UC medial range: 3.3 ± 3.3 mm; UC lateral range: 8.0 ± 3.2 mm; p < 0.001). A statistically significant greater degree of flexion was clinically recorded at follow-up visit in the MC group respect to the UC group (126° vs 101°-p = 0.003). CONCLUSION: The present study did not show difference in the medial pivot behavior between ultra-congruent and medial-congruent total knee arthroplasty when implanted with mechanical alignment; however, the MC group demonstrated a greater degree of flexion. The MC design examined is a valid alternative to the UC design, allowing to achieve a screw-home movement restoration combined with a high flexion. LEVEL OF EVIDENCE: IV.

Anterior cruciate ligament reconstruction with lateral plasty restores anterior-posterior laxity in the case of concurrent partial medial meniscectomy.

PURPOSE: To evaluate the in vivo knee laxity in the presence of a partial medial meniscectomy before and after a single-bundle ACL reconstruction with a lateral plasty (SBLP) and to compare it with the knee laxity after a single-bundle ACL reconstruction (SB). METHODS: One-hundred and one patients with ACL tear were enrolled in the study and grouped according to the surgical technique and the meniscus treatment: regarding the SBLP technique (n = 55), 31 patients underwent isolated ACL reconstruction ("SBLP Isolated ACL Group"), while 24 patients underwent combined ACL reconstruction and partial medial meniscectomy ("SBLP ACL + MM Group"); regarding the SB technique (n = 46), 33 patients underwent isolated ACL reconstruction ("SB Isolated ACL Group"), while 13 patients underwent combined ACL reconstruction and partial medial meniscectomy ("SB ACL + MM Group"). Anterior-posterior clinical laxity at 30° (AP30) and 90° (AP90) of knee flexion was quantified before and after surgery through a surgical navigation system dedicated to kinematic assessment. RESULTS: In the ACL-deficient status, the antero-posterior laxity was significantly higher in the presence of a combined MM in both the AP30 and the AP90, with no differences between the two surgical techniques. After the ACL reconstruction, both AP30 and AP90 translations decreased significantly (p < 0.0001) compared to the ACL-deficient status. No differences were found for AP30 and AP90 between SBLP Isolated ACL and SBLP + MM groups, while a significantly higher AP90 translation was found for the SB + MM group compared to the SB Isolated ACL group. Moreover, the AP90 translation in the SB ACL + MM group was significantly higher than the one of the other three groups, i.e., SBLP ACL + MM, SB, and SBLP Isolated ACL group. CONCLUSION: The ACL reconstruction with lateral plasty reduced the AP knee laxity caused by the medial meniscectomy in the context of an ACL surgery. LEVEL OF EVIDENCE: Level II.

Severe bicompartmental bone bruise is associated with rotatory instability in anterior cruciate ligament injury.

PURPOSE: The presence and severity of bone bruise is more and more investigated in the non-contact anterior cruciate ligament (ACL) injury context. Recent studies have advocated a correlation between bone bruise and preoperative knee laxity. The aim of the present study was to investigate the correlation between bone bruise and preoperative rotatory knee laxity. METHODS: Twenty-nine patients (29.1 ± 9.8 years) with MRI images at a maximum of 3 months after ACL injury (1.6 ± 0.8 months) were included. The bone bruise severity was evaluated according to the International Cartilage Repair Society (ICRS) scale for lateral femoral condyle, lateral tibial plateau, medial femoral condyle, and medial tibial plateau. The intraoperative rotational knee laxity was evaluated through a surgical navigation system in terms of internal-external rotation at 30° and 90° of knee flexion (IE30, IE90) and internal-external rotation and acceleration during pivot-shift test (PS IE, PS ACC). The KOOS score was also collected. The association between ICRS grade of bone bruise and rotational laxity or KOOS was investigated. RESULTS: Significant correlation (p < 0.05) was found between the bone bruise severity on the medial tibial plateau and rotational laxity (IE90, PS IE, and PS ACC) and between the severity of bone bruise on femoral lateral condyle and KOOS-Symptoms sub-score. The presence of bone bruise on the medial tibial plateau was significantly associated with a lateral femoral notch sign > 2 mm (very strong odds ratio). No kinematical differences were found between none-to-deep and extensive-generalized lateral bone bruise, while higher IE30 and IE90 were found in extensive-generalized bicompartmental bone bruise than isolated extensive-generalized lateral bone bruise. CONCLUSION: A severe bicompartmental bone bruise was related to higher rotatory instability in the intraoperative evaluation of ACL deficient knees. The severity of edema on the medial tibial plateau was directly correlated with higher intraoperative pivot shift, and the size of edema on the lateral femoral condyle was associated with lower preoperative clinical scores. LEVEL OF EVIDENCE: Level II.

In vivo kinematic comparison between an ultra-congruent and a posterior-stabilized total knee arthroplasty design by RSA.

PURPOSE: The aim of the present study was to compare the in vivo under weight-bearing kinematic behavior of a posterior-stabilized (PS) and an ultra-congruent (UC) total knee arthroplasty (TKA) model during a sit-to-stand motor task, a common activity of daily life. METHODS: A cohort of 16 randomly selected patients (8 PS Persona Zimmer, 8 UC Persona Zimmer) was evaluated through dynamic radiostereometric analysis (RSA) at a minimum of 9 months after TKA, during the execution of a sit-to-stand. The anteroposterior (AP) translation of the femoral component and the AP translation of the low point of medial and lateral femoral compartments were compared through Student's t test (p < 0.05). RESULTS: A significantly greater anterior translation of the femoral component was found for the PS group compared to the UC group. The flexion interval where statistical significance was found was between 30° and 0° (p = 0.017). Both groups showed a significantly greater anterior translation of the low point of the lateral compartment with respect to the medial one (PS: p = 0.012, UC: p = 0.018). This was consistent with a medial-pivot pattern. Furthermore, a significantly greater anterior translation of the medial compartment was found in the PS group compared to the UC group (p = 0.001). The same pattern was observed for the lateral compartment (p = 0.006). CONCLUSIONS: The TKA designs evaluated in the present study showed comparable in-vivo kinematics with regards to medial pivot pattern but differences in absolute AP translation. Specifically, the UC design showed greater AP stability than the PS design. This finding could be positive in terms of implant stability, but negative in terms of premature polyethylene wear and thus implant failure. This remains to be verified in studies with a larger sample size and longer follow-up. LEVEL OF EVIDENCE: IV.

Over-constrained kinematic of the medial compartment leads to lower clinical outcomes after total knee arthroplasty.

PURPOSE: To investigate if postoperative clinical outcomes correlate with specific kinematic patterns after total knee arthroplasty (TKA) surgery. The hypothesis was that the group of patients with higher clinical outcomes would have shown postoperative medial pivot kinematics, while the group of patients with lower clinical outcomes would have not. METHODS: 52 patients undergoing TKA surgery were prospectively evaluated at least a year of follow-up (13.5 ± 6.8 months) through clinical and functional Knee Society Score (KSS), and kinematically through dynamic radiostereometric analysis (RSA) during a sit-to-stand motor task. Patients received posterior-stabilized TKA design. Based on the result of the KSS, patients were divided into two groups: "KSS > 70 group", patients with a good-to-excellent score (93.1 ± 6.8 points, n = 44); "KSS < 70 group", patients with a fair-to-poor score (53.3 ± 18.3 points, n = 8). The anteroposterior (AP) low point (lowest femorotibial contact points) translation of medial and lateral femoral compartments was compared through Student's t test (p < 0.05). RESULTS: Low point AP translation of the medial compartment was significantly lower (p < 0.05) than the lateral one in both the KSS > 70 (6.1 mm ± 4.4 mm vs 10.7 mm ± 4.6 mm) and the KSS < 70 groups (2.7 mm ± 3.5 mm vs 11.0 mm ± 5.6 mm). Furthermore, the AP translation of the lateral femoral compartment was not significantly different (p > 0.05) between the two groups, while the AP translation of the medial femoral compartment was significantly higher for the KSS > 70 group (p = 0.0442). CONCLUSION: In the group of patients with a postoperative KSS < 70, the medial compartment translation was almost one-fourth of the lateral one. Surgeons should be aware that an over-constrained kinematic of the medial compartment might lead to lower clinical outcomes. LEVEL OF EVIDENCE: II.

A 2D video-analysis scoring system of 90° change of direction technique identifies football players with high knee abduction moment.

PURPOSE: Abnormal joint biomechanics and poor neuromuscular control are modifiable risk factors for Anterior Cruciate Ligament (ACL) injury. Although 3D motion capture is the gold standard for the biomechanical evaluation of high-speed multidirectional movements, 2D video analysis is a growing-interest alternative because of its higher cost-effectiveness and interpretability. The aim of the present study was to explore the possible association between a 2D evaluation of a 90° change of direction (COD) and the KAM measured with gold standard 3D motion analysis. METHODS: Thirty-four competitive football (soccer) players (age 22.8 ± 4.1, 18 male and 16 females) were enrolled. Each athlete performed a series of pre-planned 90° COD at the maximum speed possible in a laboratory equipped with artificial turf. 3D motion analysis was recorded using 10 stereophotogrammetric cameras, a force platform, and three high-speed cameras. The 2D evaluation was performed through a scoring system based on the video analysis of frontal and sagittal plane joint kinematics. Five scoring criteria were adopted: limb stability (LS), pelvis stability (PS), trunk stability (TS), shock absorption (SA), and movement strategy (MS). For each criterion, a sub-score of 0/2 (non-adequate), 1/2 (partially adequate), or 2/2 (adequate) was attributed to the movement, based on objective measurements. The intra-rater and inter-rater reliability were calculated for each criterion and the total score. The Knee Abduction Moment (KAM) was extracted from the 3D motion analysis and grouped according to the results of the 2D evaluation. RESULTS: Excellent intra-rater reliability (ICC > 0.88) and good-to-excellent inter-rater reliability (ICC 0.68-0.92) were found. Significantly higher KAM was found for athletes obtaining a 0/2 score compared to those obtaining a 2/2 score in all the sub-criteria and the total score (20-47% higher, p < 0.05). The total score and the LS score showed the best discriminative power between the three groups. CONCLUSION: The 2D video-analysis scoring system here described was a simple and effective tool to discriminate athletes with high and low KAM in the assessment of a 90° COD and could be a potential method to identify athletes at high risk of non-contact ACL injury. LEVEL OF EVIDENCE: IV.

On-Field Biomechanical Assessment of High and Low Dive in Competitive 16-Year-Old Goalkeepers through Wearable Sensors and Principal Component Analysis.

Diving saves are the main duty of football goalkeepers. Few biomechanical investigations of dive techniques have been conducted, none in a sport-specific environment. The present study investigated the characteristics of goalkeepers' dive in preferred (PS) and non-preferred (nPS) side through an innovative wearables-plus-principal-component analysis (PCA) approach. Nineteen competitive academy goalkeepers (16.5 ± 3.0 years) performed a series of high and low dives on their PS and nPS. Dives were performed in a regular football goal on the pitch. Full-body kinematics were collected through 17 wearable inertial sensors (MTw Awinda, Xsens). PCA was conducted to reduce data dimensionality (input matrix 310,878 datapoints). PCA scores were extracted for each kinematic variable and compared between PS and nPS if their explained variability was >5%. In high dive, participants exhibited greater hip internal rotation and less trunk lateral tilt (p < 0.047, ES > 0.39) in PS than nPS. In low dives, players exhibited greater ipsilateral hip abduction dominance and lower trunk rotation (p < 0.037, ES > 0.40) in PS than nPS. When diving on their nPS, goalkeepers adopted sub-optimal patterns with less trunk coordination and limited explosiveness. An ecological testing through wearables and PCA might help coaches to inspect relevant diving characteristics and improve training effectiveness.

ACL deficiency influences medio-lateral tibial alignment and knee varus-valgus during in vivo activities.

PURPOSE: The role of the anterior cruciate ligament (ACL) in knee biomechanics in vivo and under weight-bearing is still unclear. The purpose of this study was to compare the tibiofemoral kinematics of ACL-deficient knees to healthy contralateral ones during the execution of weight-bearing activities. METHODS: Eight patients with isolated ACL injury and healthy contralateral knees were included in the study. Patients were asked to perform a single step forward and a single leg squat first with the injured knee and then with the contralateral one. Knee motion was determined using a validated model-based tracking process that matched subject-specific MRI bone models to dynamic biplane radiographic images, under the principles of Roentgen stereophotogrammetric analysis (RSA). Data processing was performed in a specific software developed in Matlab. RESULTS: Statistically significant differences (p < 0.05) were found for single leg squat along the frontal plane: ACL-deficient knees showed a more varus angle, especially at the highest knee flexion angles (40°-50° on average), compared to the contralateral knees. Furthermore, ACL-deficient knees showed tibial medialization along the entire task, while contralateral knees were always laterally aligned. This difference became statistically relevant (p < 0.05) for knee flexion angles included between 0° and about 30°. CONCLUSION: ACL-deficient knees showed an abnormal tibial medialization and increased varus angle during single leg squat when compared to the contralateral knees. These biomechanical anomalies could cause a different force distribution on tibial plateau, explaining the higher risk of early osteoarthritis in ACL deficiency. The clinical relevance of this study is that also safe activities used in ACL rehabilitation protocols are significantly altered in ACL deficiency. LEVEL OF EVIDENCE: III.

A 2D qualitative movement assessment of a deceleration task detects football players with high knee joint loading.

PURPOSE: The deceleration (pressing) is a common situational pattern leading to anterior cruciate ligament (ACL) injury in football. Although mainly assessed for performance purposes, a stronger focus on movement quality might support the screening of at-risk athletes. The aim of the present study was to describe a 2D scoring system for the assessment of the deceleration task and to associate it with the knee joint loading (knee abduction moment) evaluated through the gold standard 3D motion capture. The hypothesis was that lower 2D scores would be associated with higher knee joint loading. METHODS: Thirty-four competitive football (soccer) players (age 22.8 ± 4.1, 16 females) performed a series of deceleration tasks. 3D motion analysis was recorded using ten stereophotogrammetric cameras, a force platform, and three high-speed cameras. The 2D qualitative assessment was performed via a scoring system based on the video analysis of frontal and lateral planes joint kinematics for five scoring criteria. The intra- and inter-rater reliabilities were calculated for each 2D scoring criteria. The peak knee abduction moment was extracted and grouped according to the results of the 2D evaluation. RESULTS: An ICC > 0.94 was found for all the 2D scoring criteria, both for intra-rater and inter-rater reliability. The players with low 2D frontal plane scores and low total scores (0-4) showed significantly higher peak knee abduction moment values (p < 0.001). A significant negative rank correlation was found between the total score and the peak knee abduction moment (ρ = - 0.25, p < 0.001). CONCLUSIONS: The qualitative 2D scoring system described successfully discerned between athletes with high and low knee joint loading during a deceleration task. The application of this qualitative movement assessment based on a detailed and accurate scoring system is suitable to identify players and patients with high knee joint loading (high knee abduction moments) and target additional training in the scenario of the primary and secondary ACL injury risk reduction. LEVEL OF EVIDENCE: Level IV.

Knee position at the moment of bone bruise could reflect the late phase of non-contact anterior cruciate ligament injury rather than the mechanisms leading to ligament failure.

PURPOSE: The aim of the present study was to trace knee position at the time of bone bruise (BB) and investigate how much this position departed from the knee biomechanics of an in vivo flexion-extension. METHODS: From an original cohort of 62 patients, seven (11%) presented bicompartmental edemas and were included in the study. 3D models of bones and BB were obtained from MRI. Matching bone edemas, a reconstruction of the knee at the moment of BB was obtained. For the same patients, knee kinematics of a squat was calculated using dynamic Roentgen sterephotogrammetric analysis (RSA). Data describing knee position at the moment of BB were compared to kinematics of the same knee extrapolated from RSA system. RESULTS: Knee positions at the moment of BB was significantly different from the kinematics of the squat. In particular, all the patients' positions were out of squat range for both anterior and proximal tibial translation, varus-valgus rotation (five in valgus and two in varus), tibial internal-external rotation (all but one, five externally and one internally). A direct comparison at same flexion angle between knee at the moment of BB (average 46.1° ± 3.8°) and knee during squat confirmed that tibia in the former was significantly more anterior (p < 0.0001), more externally rotated (6.1 ± 3.7°, p = 0.04), and valgus (4.1 ± 2.4°, p = 0.03). CONCLUSION: Knee position at the moment of Bone bruise position was out of physiological in-vivo knee range of motion and could reflect a locked anterior subluxation occurring in the late phase of ACL injury rather than the mechanism leading to ligament failure. LEVEL OF EVIDENCE: Level IV.

Good results are reported at 60-month follow-up after medial patello-femoral ligament reconstruction with fascia lata allograft for recurrent patellar dislocation.

PURPOSE: The aim of this study was to evaluate the efficacy of a new minimally invasive surgical technique for the reconstruction of the medial patellofemoral ligament (MPFL) with fascia lata allograft at 60-month minimum follow-up. METHODS: Nineteen consecutive patients with chronic recurrent patellar dislocation were treated with MPFL reconstruction (53% isolate procedure, 47% in combination with other treatments). Seventeen patients (11 males/6 females) were available at 60-month follow-up and were clinically evaluated with validated scores. New episodes of patellar dislocation were considered failures. Radiographic and CT scan evaluation were executed preoperatively and at 60-month follow-up. RESULTS: All clinical scores improved from preoperative assessment to 24-month and 60-month follow-up (p < 0.001). Kujala score increased from 61.2 ± 18.1 to 86.7 ± 8.7 and 82.1 ± 10.2; KOOS increased from 54.5 ± 19 to 86.8 ± 9.6 and 84.3 ± 7.6; VAS for pain decreased from 5.1 ± 2.2 to 2.4 ± 1.5 and 1.7 ± 1.2; Tegner score increased from 3 [2-4] to 5 [3-8] and 5 [3-9], respectively. Objective IKDC improved too. No significant improvements between the 24-month and 60-month follow-up evaluations were recorded. Anterior knee pain was reported in two patients (12%). Treatment failure, a new episode of patellar dislocation 25 months after the surgery, was observed in one patient (6%). Radiographic OA changes were not statistically significant between preop and 60-month follow-up. Tuberosity-troclear groove (TT-TG) distance and the patellar tilt angle were subjected to significant changes due to MPFL reconstruction and associated procedures. CONCLUSION: MPFL reconstruction with fascia lata allograft, alone or combined with other procedures, is a reliable treatment option for recurrent patellar dislocation with a success rate of 94% and without cartilage deterioration at 60-month follow-up. LEVEL OF EVIDENCE: IV.