Anterior cruciate ligament (ACL) injuries are one of the most common acute sports injuries in male football. Recently, the role of muscle fiber type (MFT) distribution in both athletic performance and hamstring muscle injury risk has gained popularity in sports medicine. As the hamstring muscle unit is a biomechanical synergist of the ACL, this study intended to verify to what extent hamstring MFT distribution is related to ACL injury in football players, using proton magnetic resonance spectroscopy (1H-MRS). Thirty-seven male football players with a recent history of ACL injury and 49 matched controls were submitted to 1H-MRS evaluation of the hamstrings. MFT distribution was estimated based on the relative carnosine content. Results demonstrated that carnosine contents differed significantly based on ACL history presence, with higher carnosine content in the injury group. Average carnosine contents of 0.204 ± 0.011 and 0.169 ± 0.008 AU were seen in the ACL injury and control groups, respectively (p = 0.011). FT, IT, and ST fiber dominances were estimated to be 27%, 46%, and 27% in the ACL group and 18%, 43%, and 39% in the control group. ACL injury history appears to present a significant association with hamstring muscle carnosine content, suggesting higher FT fiber dominance might be a consequence or a cause. Future prospective research is needed to verify to what extent intramuscular carnosine content is causally related to (non-contact) ACL injury risk. In case of prospective confirmation, MFT determination might be valuable in injury prevention and load management strategy development.

Over the past decade, robot assistance has emerged as an innovative and rapidly advancing tool in total knee arthroplasty (TKA). Despite technological advancements, the evaluation of the soft-tissue envelope during TKA often relies on subjective and rudimentary assessments by the surgeon. This literature review explores the relationship between objective intraoperative and postoperative laxity measurements in the coronal and sagittal planes and patient-reported outcome measures (PROMs) following TKA. A literature review was conducted using PubMed/MEDLINE and Embase to identify studies on intra- or postoperative laxity measurements in TKA and their correlation with PROMs. Inclusion criteria required studies on TKA patients with quantifiable coronal and/or sagittal laxity measurements and postoperative PROMs linked to these measurements. Thirty-four studies met inclusion criteria: ten on sagittal laxity, twenty-seven on coronal laxity, and three on both. Follow-up ranged from 1 month to over 8 years. Sagittal laxity thresholds of 5–10 mm under applied loads of 89–133 N were associated with better functional outcomes, whereas excessive (> 10 mm) or overly tight (< 5 mm) laxity correlated with reduced satisfaction. Medial laxity in the coronal plane was linked to lower PROMs, while the impact of lateral laxity on PROMs was less conclusive. Objective laxity parameters correlate with PROMs, particularly a stable medial compartment throughout the range of motion, while the role of lateral laxity remains unclear. Systematic use of objective soft-tissue evaluations may enhance PROMs. While fixed-force assessments are standardized, personalized approaches with variable forces tailored to individual patients might be needed for optimal outcomes.

Dissatisfaction following primary total knee arthroplasty (pTKA) is higher in patients with preoperative low-grade osteoarthritis (OA), but its impact on revision risk remains unclear. This study aimed to identify predictors for revision surgery within 10 years following pTKA, focusing on radiographic severity of OA using the Kellgren-Lawrence (KL) grading system, along with other demographic and radiographic factors. This retrospective case-control study was conducted at two European tertiary referral centers. The case group included 142 patients who underwent aseptic revision total knee arthroplasty (rTKA) between 2007 and 2023, within 10 years following pTKA. A 2:1 control group of 284 patients who had pTKA between 2011 and 2014, with no revision surgery within 10 years, was selected. Collected data included age, sex, body mass index (BMI), side of surgery, and American Society of Anesthesiologists (ASA) classification. Radiographic data were collected, requiring a preoperative radiograph to assess the KL grade. Univariate analyses identified potential predictors for rTKA, and multivariable logistic regression assessed their relationship with revision risk. Patients requiring rTKA were significantly younger at the time of pTKA. For each additional year of age, the revision risk decreased by 6

BACKGROUND:Functional knee positioning (FKP) in robotic-assisted (RA) total knee arthroplasty (TKA) aims to optimize soft-tissue balance through patient-specific implant fine-tuning. However, it remains unclear (1) how intraoperative ligament laxity affects joint awareness and (2) whether the discrepancy between intraoperative planned and achieved laxity is affected by preoperative coronal limb alignment or fixed flexion deformity (FFD). METHODS:This retrospective study analyzed 130 patients undergoing image-based RA TKA with FKP using a cementless cruciate-retaining implant. Intraoperative adjustments were made to balance the flexion-extension laxity, targeting one to two mm larger lateral flexion laxity. Medial and lateral gaps before and after implant positioning were recorded at near extension and 90° flexion. Patient-reported outcome measures (PROMs), including the Forgotten Joint Score (FJS-12) and a 5-point Likert scale for satisfaction, were assessed at a minimum of one year postoperatively to investigate correlations between PROMs and final intraoperative laxities. The impact of preoperative coronal limb alignment, measured on long-leg radiographs, and FFD on final laxities was also evaluated. RESULTS:Final laxities were: median medial extension laxity 1.5 mm (1.0 to 2.0), lateral extension laxity 1.5 mm (1.1 to 2.0), medial flexion laxity 1.0 mm (0.5 to 1.5), and lateral flexion laxity 2.0 mm (1.5 to 2.5). At one year, the FJS-12 was 87.4 ± 14.5. A weak inverse correlation was observed between medial flexion laxity and FJS-12 (r = -0.18, P = 0.047); no other laxities were associated with PROMs. Sensitivity analyses showed no relevant laxity cutoffs influencing PROMs. Valgus knees exhibited larger changes between planned and final medial extension laxity compared with varus knees (P < 0.002). Unlike cases without FFD, those with preoperative FFD >10° showed no discrepancy between planned and final extension laxities (P < 0.003). CONCLUSIONS:Image-based RA TKA using FKP achieves good-to-excellent clinical outcomes at one year, with a balanced symmetric extension laxity. Coronal limb alignment and FFD significantly influence the deviation between planned and final extension laxity and should be considered during surgical planning.

OBJECTIVE:Knee osteoarthritis (KOA) is a leading cause of global disability and remains challenging to treat. Blood flow restriction (BFR) shows promising rehabilitation outcomes, but its lasting effects in KOA are lacking. This study aimed to determine the 1-year outcomes of a BFR-enhanced exercise therapy programme in patients with KOA. METHODS:This study included 120 patients (33 male, 87 female) from a previously published randomised controlled trial comparing 12 weeks of traditional exercise therapy with and without BFR, performed twice per week. For the current analysis, patients were reassessed at 1 year. The primary outcome was the Knee Osteoarthritis Outcome Score (KOOS) questionnaire, with secondary outcomes including muscle strength and a functional test battery. Data on knee joint injections and activity levels were also reviewed at 1-year follow-up. Analyses consisted of linear mixed models with Dunn-Sidak corrections for multiple comparisons, with an intention to treat approach (NCT04996680). RESULTS:Clinically meaningful improvements at 1 year were found in favour of the BFR group for KOOS subscales 'pain' (mean difference (MD): 15.1 points ES=0.79, p=0.0039), 'symptoms' (MD: 10.5 points, ES=0.51, p=0.0074), 'activities of daily living' (ADL) (MD: 11.3 points, ES=0.54, p=0.0054) and 'quality of life' (QoL) (MD: 14.7 points, ES=0.61, p=0.0032) compared with exercise therapy without BFR. The BFR group outperformed the non-BFR group for the functional tests, and muscle strength remained significantly higher at 1 year in the BFR group (ES=0.48, p=0.0010) as opposed to no BFR. The BFR group was more active by 1.5 hours/week (p=0.036) and had 3.6 times lower odds of receiving knee injections compared with the non-BFR group. CONCLUSION:A 12-week BFR-enhanced exercise therapy programme provides benefits for pain, symptoms, ADL, QoL, muscle strength and functional capacity at 1-year follow-up while reducing the need for knee injections by 63.4% compared with traditional exercise therapy alone.

The intraoperative registration of the bones play a crucial role in image‐based computer‐assisted knee arthroplasty to achieve accurate implant placement and to create reliable stereotactic bone boundaries for robot‐assisted surgical systems.

Purpose Forced external rotation is hypothesized as the key mechanism of syndesmotic ankle injuries. This complex trauma pattern ruptures the syndesmotic ligaments, inducing a three-dimensional deviation from the normal distal tibiofibular joint configuration. However, current diagnostic imaging modalities are impeded by a two-dimensionalassessment, without taking into account ligamentous stabilizers. Therefore, our aim is two-fold: (1) to construct an articulated statistical shape model of the normal ankle with inclusion of ligamentous morphometry and (2) to apply this model in the assement of a clinical cohort of paient with syndesmotic ankle injuries. Methods Three-dimensional models of the distal tibiofibular joint were analyzed in asymptomatic controls (N= 76; Mean age 63 +/- 19 years),patients with syndesmotic ankle injury (N = 13; Mean age 35 +/- 15 years), and their healthy contralateral equivalent (N = 13). Subsequently, the statiscal shape model was generated after aligning all ankles based on the distal tibia. The position of the syndesmotic ligaments was predicted based on previously validated iterative shortest path calculation methodology. Evaluation of the model was described by means of accuracy, compactness and generalization. Canonical Correlation Analysis was performed to assess the influence of syndesmotic lesions on the distal tibiofibular joint congruency. Results Our presented model contained an accuracy of 0.23 +/- 0.028 mm. Mean prediction accuracy of ligament insertions was 0.53 +/- 12 mm. A statistically significant difference in anterior syndesmotic distance was found between ankles with syndesmotic lesions and healthy controls (95% CI [ 0.32 , 3.29], p = 0.017). There was a significant correlation between presence of syndesmotic injury and the morphological distal tibiofibular configuration (r = 0.873, p <0,001). Conclusion In this study, we constructed a bony and ligamentous statistical model representing the distal tibiofibular joint Furthermore, the presented model was able to detect an elongation injury of the anterior inferior tibiofibular ligament after traumatic syndesmotic lesions in a clinical patient cohort.

The application of robotics in the operating theatre for knee arthroplasty remains controversial. As with all new technology, the introduction of new systems might be associated with a learning curve. However, guidelines on how to assess the introduction of robotics in the operating theatre are lacking. This systematic review aims to evaluate the current evidence on the learning curve of robot-assisted knee arthroplasty. An extensive literature search of PubMed, Medline, Embase, Web of Science, and Cochrane Library was conducted. Randomized controlled trials, comparative studies, and cohort studies were included. Outcomes assessed included: time required for surgery, stress levels of the surgical team, complications in regard to surgical experience level or time needed for surgery, size prediction of preoperative templating, and alignment according to the number of knee arthroplasties performed. A total of 11 studies met the inclusion criteria. Most were of medium to low quality. The operating time of robot-assisted total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) is associated with a learning curve of between six to 20 cases and six to 36 cases respectively. Surgical team stress levels show a learning curve of seven cases in TKA and six cases for UKA. Experience with the robotic systems did not influence implant positioning, preoperative planning, and postoperative complications. Robot-assisted TKA and UKA is associated with a learning curve regarding operating time and surgical team stress levels. Future evaluation of robotics in the operating theatre should include detailed measurement of the various aspects of the total operating time, including total robotic time and time needed for preoperative planning. The prior experience of the surgical team should also be evaluated and reported. Cite this article: Bone Joint J 2020;102-B(4):407-413.

The focus in the evaluation of total knee arthroplasty has shifted from objective measures of implant position and knee function, to patient-reported outcome measures (PROMs). The relation between these two measures was investigated and the possibility of prediction of the patient satisfaction level was evaluated by defining thresholds for improvement of (1) range of motion (ROM), (2) 6-min walk test (6MWT), (3) sit-to-stand test (STS) and (4) quadriceps force after TKA?

Knee replacement surgery has made a huge evolution during the past decades. For further improvements of knee arthroplasty, dynamic knee simulators are used for fully instrumented ex-vivo tests. This paper provides a closer look at the validation of the rig. Therefore, a hinge model is constructed, resulting in an unambiguous evaluating method. The actual position of the ankle and the reaction forces at the ankle are measured and compared with the simulations. The results indicate an excellent agreement between the outcome of the numerical simulations and the measured values. The kinematics and kinetics of the rig are accordingly considered as validated. In the future, the behaviour of a more realistic knee representation will be evaluated.

Mots cles : Appareillage ; Osteo-integration ; Amputation ; Transfemoral ; Transhumeral ; Transradiale ; Pouce ; Reconstruction bionique Depuis son introduction dans le milieu des annees 1960, l’utilisation de protheses osteo-integrees en titane est devenue une technique de routine. Les implants intra-epidermiques ont fourni des solutions pour la fixation des epitheses dans les atteintes faciales et pour le transfert des vibrations acoustiques lors de l’utilisation d’aides auditives (BAHA). Les connaissances et l’experience acquises a partir de ces modeles se sont averes essentiels au developpement d’une solution similaire pour la fixation des exoprothese principalement sur les moignons femoral et de l’humerus problematiques. Les premiers patients amputes ont ete traites par Branemark et al. a Goteborg en 1990 (transfemoral et pouce, transradial en 1992, transhumeral en 1994). Des implants standardises et un protocole de rehabilitation detaillee (OPRA) ont ete developpes depuis 1999. Ce traitement n’est pas un substitut a une prothese exosquelettique par manchon bien toleree. Toutefois, il peut etre une alternative interessante pour les patients a moignons d’amputation courts, plaies chroniques ou autres troubles trophiques empechant l’utilisation reguliere d’un manchon. Dans cette population de patients des etudes ont montre des gains fonctionnels et de qualite de vie sur les resultats a moyen terme. La qualite de la fixation osseuse des implants dentaires et des protheses de hanche sans ciment semble se comporter de facon similaire dans le temps. Ces donnees permettent d’etre optimiste sur la survie a long terme de ces implants. Les complications infectieuses restent evidemment une preoccupation avec une incidence dans des limites raisonnables. Les infections superficielles peuvent etre traitees de facon conservatrice. Comme pour les implants dentaires, les infections profondes sont traitees selon les principes standards, le plus souvent sans extraction de l’implant. Faisant confiance a l’evolution de ces techniques, nous les avons integrees dans notre hopital. Notre premier ampute transhumeral a ete opere en mai 2010. Des patients amputes en transfemoral ont suivi depuis. Notre discussion portera sur les bases du programme de traitement, les explorations complementaires et les aspects techniques. Les recentes innovations techniques par implants peuvent optimiser l’effet d’autres evolutions dans le traitement des amputes, comme la re-innervation musculaire ciblee. La perspective de reconstruction de membres fonctionnels bioniques parait ainsi devenir plus realiste.

OBJECTIVE:To characterize the epidemiology of injuries in post-high school male and female athletes in the rapidly growing international sport of contact flag football. DESIGN:Prospective injury-observational study. SETTING:Kraft Stadium, Jerusalem, Israel. PARTICIPANTS:A total of 1492 players, consisting of men (n = 1252, mean age, 20.49 ± 5.11) and women (n = 240, mean age, 21.32 ± 8.95 years), participated in 1028 games over a 2-season period (2007-2009). MAIN OUTCOME MEASURES:All time-loss injuries sustained in game sessions were recorded by the off-the-field medical personnel and followed up by a more detailed phone injury surveillance questionnaire. RESULTS:One hundred sixty-three injuries were reported, comprising 1 533 776 athletic exposures (AEs). The incidence rate was 0.11 [95% confidence interval (CI), 0.09-0.12] per 1000 AEs, and incidence proportion was 10.66% (95% CI, 9.10-12.22). Seventy-six percent of the injuries were extrinsic in nature. Thirty percent of the injuries were to the fingers, thumb, and wrist, 17% to the knee, 17% to the head/face, 13% to the ankle, and 11% to the shoulder. CONCLUSIONS:Contact flag football results in a significant amount of moderate to severe injuries. These data may be used in the development of a formal American flag football injury database and in the development and implementation of a high-quality, randomized, prospective injury prevention study. This study should include the enforcement of the no-pocket rule, appropriate headgear, self-fitting mouth guards, the use of ankle braces, and changing the blocking rules of the game.

Methodology: A retrospective review based on a prospective database was performed on 146 consecutive revision TKA’s. An independent observer measured clinical outcomes using the Knee Society Knee (KS) and Function Score (FS). X-ray evaluation, including rating of radiolucent lines, tibiofemoral and patellofemoral alignment, was carried out by an independent radiologist. ANOVA was used for statistical analysis, with significance set at p≤0.05 (SPSS version 15.0). Post-hoc Bonferroni testing was carried out for single variables including primary cause of failure, age at revision surgery, time span between index operation and revision, type of index operation, partial or total revision and the performance of a tuberosity osteotomy. Results: 146 files were available in 135 patients. 16 patients deceased (17 knees) during the follow-up period and 2 patients (2 knees) were lost to follow-up. 117 patients (127 knees) were available for evaluation. Age at revision surgery averaged 67.7 years (range 32.3–88.1). Mean follow-up time was 4.5 years (range 1–14). Patients had revision TKA between 51 days and 16.1 years (average 4.7 years) after the index TKA. 54% of the early revisions were due to infection and instability, 55% of late revisions were caused by polyethylene-wear and loosening. The mean postoperative KS was 70.8 with a mean improvement of 43.2 points as compared to pre-operative. The mean postoperative FS was 52.9 with a mean improvement of 25.4 points. Grouping outcomes according to cause of failure of the index TKA gave the following ranking from better to worse, without being significant: wear (n=15; KS 80.8; range 43–99, SD 17.5), loosening (n=44; KS 75.8; range 15–100, SD=21.2), malalignment (n=19; KS 70.0; range 9–95, SD 25.9), instability (n=33; KS 68.2; range 5–100, SD 24.1), others (n=16; KS 66.7; range 10–100, SD 25.9), and infection (n=21; KS 64.2; range 3–100, SD 31.7). Survivorship at 5 years was 90.0% (CI 86.4% –93.6%), at 10 years 84,6% (CI 77.0% –92.3%) and at 14 years 84,6% (CI 37.7% –131.6%). Significant better outcomes were seen with late revisions, index operation being partial knee replacement and older age at revision. More failures (p=0.002) were seen with early revisions. In 32.6% of the patients radiolucent lines of ≥1 mm were observed. Points were granted with the use of a Radiolucency Scoring Scheme. Patients with less than 4 points (n=87, mean KS 71.2) had better outcomes than patients with 4 or more points (n=8, mean KS 56.4). 87% of patients were aligned within 4° of mechanical axis. Conclusion: Outcomes of revision TKA are inferior to primary TKA. Early failures were mainly caused by infection, instability, malalignment. Grouping revision TKA’s to etiology of failure did not lead to significant differences in outcomes. Significant better outcomes were reported for late revisions, patients with older age at revision surgery and partial knee replacement. Survivorship analysis was significally better for late than for early revisions.