Knee injuries account for the sports-related increased risk of knee osteoarthritis

A synoptic literature review of animal models for investigating the biomechanics of knee osteoarthritis

Osteoarthritis (OA) is a common chronic disease largely driven by mechanical factors, causing significant health and economic burdens worldwide. Early detection is challenging, making animal models a key tool for studying its onset and mechanically-relevant pathogenesis. This review evaluate current use of preclinical in vivo models and progressive measurement techniques for analysing biomechanical factors in the specific context of the clinical OA phenotypes. It categorizes preclinical in vivo models into naturally occurring, genetically modified, chemically-induced, surgically-induced, and non-invasive types, linking each to clinical phenotypes like chronic pain, inflammation, and mechanical overload. Specifically, we discriminate between mechanical and biological factors, give a new explanation of the mechanical overload OA phenotype and propose that it should be further subcategorized into two subtypes, post-traumatic and chronic overloading OA. This review then summarises the representative models and tools in biomechanical studies of OA. We highlight and identify how to develop a mechanical model without inflammatory sequelae and how to induce OA without significant experimental trauma and so enable the detection of changes indicative of early-stage OA in the absence of such sequelae. We propose that the most popular post-traumatic OA biomechanical models are not representative of all types of mechanical overloading OA and, in particular, identify a deficiency of current rodent models to represent the chronic overloading OA phenotype without requiring intraarticular surgery. We therefore pinpoint well standardized and reproducible chronic overloading models that are being developed to enable the study of early OA changes in non-trauma related, slowly-progressive OA. In particular, non-invasive models (repetitive small compression loading model and exercise model) and an extra-articular surgical model (osteotomy) are attractive ways to present the chronic natural course of primary OA. Use of these models and quantitative mechanical behaviour tools such as gait analysis and non-invasive imaging techniques show great promise in understanding the mechanical aspects of the onset and progression of OA in the context of chronic knee joint overloading. Further development of these models and the advanced characterisation tools will enable better replication of the human chronic overloading OA phenotype and thus facilitate mechanically-driven clinical questions to be answered.

Does Playing Football (Soccer) Really Increase the Risk of Knee Osteoarthritis? A Systematic Review and Meta-analysis

OBJECTIVE: To evaluate the relationship between football (soccer) participation and tibiofemoral knee osteoarthritis (OA), considering the influence of competitive level and previous knee injuries. DESIGN: Etiology systematic review with meta-analysis. LITERATURE SEARCH: PubMed, Embase, AMED, and Cochrane were searched for relevant publications. STUDY SELECTION CRITERIA: Studies of football players that included a control group consisting of mainly sedentary nonfootball players, and the relationship of knee OA, were considered. The studies had to report radiographically verified knee OA and specify football activity. DATA SYNTHESIS: Eleven studies, involving 1805 football players and 4022 control individuals were included. Subgroups consisting of data regarding level of play and previous injuries were also synthesized. RESULTS: The overall prevalence of knee OA among football players was increased among professional and recreational players, compared with controls. When knee injuries were excluded, there was no difference in knee OA between football players and controls (OR = 1.25; 95% CI: 0.61, 2.54). Football players with a previous knee injury had a greater risk of knee OA when compared with football players with no history of previous knee injury (OR = 4.16; 95% CI: 1.97, 8.77). CONCLUSION: Football players were at increased risk of knee OA. However, after excluding participants with a history of previous knee injury, there were no differences in knee OA between football players and controls. Previous knee injury was important for developing knee OA. Playing football, in the absence of major knee injuries, did not increase the risk of knee OA. J Orthop Sports Phys Ther 2024;54(5):1-12. Epub 26 February 2024. doi:10.2519/jospt.2024.12029.

Finding the Goldilocks Zone of Mechanical Loading: A Comprehensive Review of Mechanical Loading in the Prevention and Treatment of Knee Osteoarthritis

In this review, we discuss the interaction of mechanical factors influencing knee osteoarthritis (KOA) and post-traumatic osteoarthritis (PTOA) pathogenesis. Emphasizing the importance of mechanotransduction within inflammatory responses, we discuss its capacity for being utilized and harnessed within the context of prevention and rehabilitation of osteoarthritis (OA). Additionally, we introduce a discussion on the Goldilocks zone, which describes the necessity of maintaining a balance of adequate, but not excessive mechanical loading to maintain proper knee joint health. Expanding beyond these, we synthesize findings from current literature that explore the biomechanical loading of various rehabilitation exercises, in hopes of aiding future recommendations for physicians managing KOA and PTOA and athletic training staff strategically planning athlete loads to mitigate the risk of joint injury. The integration of these concepts provides a multifactorial analysis of the contributing factors of KOA and PTOA, in order to spur further research and illuminate the potential of utilizing the body's own physiological responses to mechanical stimuli in the management of OA.

Preclinical Cartilage Changes of the Knee Joint in Adolescent Competitive Volleyball Players: A Prospective T2 Mapping Study

PURPOSE

To investigate the potential effects of volleyball as a competitive sport in adolescence on the cartilage of knee joints using T2 mapping in MRI and identification of preclinical cartilage changes. Volleyball as an impact sport often leads to damage of the knee joint cartilage in adulthood. As T2 mapping is widely available and highly capable of detecting cartilage changes prior to conventional MRI sequences, such a detection may allow adolescent volleyball players to change their training regime before structural damage can occur to the cartilage and pose the risk of osteoarthritis.

MATERIALS AND METHODS

Comparative study of the patellar, femoral, and tibial cartilage of 60 knee joints using T2 mapping on 3 T MRI. In each case, both knees of 15 adolescent competitive volleyball athletes were compared with 15 controls.

RESULTS

In the group of competitive athletes, more focal cartilage changes were detected in the medial facet of the patellofemoral cartilage and in the medial femoral condyle of the knee joint cartilage (p = .01 and p <.05, respectively). Furthermore, the latter showed a diffused increase in maximal T2 mapping values (p <.04 right and p = .05 left). The distribution of changes seems to further depend on the player's position.

CONCLUSION

In adolescent volleyball players in competitive sports, T2 mapping demonstrates early cartilage changes in both the patellofemoral and medial femoral cartilages. The distribution of lesions depends on the player's position. Since the cascade from T2 relaxation time increase to conspicuous cartilage damage is well established, early counter-regulation (e. g., adapted training profile, targeted physiotherapy, and appropriate muscle building training) has the potential to prevent later damage.

KEY POINTS

· Volleyball as a competitive sport in adolescence leads to preclinical knee cartilage changes.. · Cartilage changes are both focal and diffuse.. · Jumping-intensive player positions seem to show more patellofemoral and running-intensive more condylar cartilage changes.. · Early detection of these changes could prevent progression to cartilage damage through adapted training..

CITATION FORMAT

· Roth C, Hirsch F, Sorge I et al. Preclinical Cartilage Changes of the Knee Joint in Adolescent Competitive Volleyball Players: A Prospective T2 Mapping Study. Fortschr Röntgenstr 2023; 195: 913 - 923.

Effects of Running on the Development of Knee Osteoarthritis: An Updated Systematic Review at Short-Term Follow-up

Background

Some studies have suggested that running increases the risk of knee osteoarthritis (OA), while others believe it serves a protective function.

Purpose

To perform an updated systematic review of the literature to determine the effects of running on the development of knee OA.

Study Design

Systematic review; Level of evidence, 4.

Methods

A systematic review was performed by searching the PubMed, Cochrane Library, and Embase databases to identify studies evaluating the effect of cumulative running on the development of knee OA or chondral damage based on imaging and/or patient-reported outcomes (PROs). The search terms used were "knee AND osteoarthritis AND (run OR running OR runner)." Patients were evaluated based on plain radiographs, magnetic resonance imaging (MRI), and PROs (presence of knee pain, Health Assessment Questionnaire-Disability Index, and the Knee injury and Osteoarthritis Outcome Score).

Results

Seventeen studies (6 level 2 studies, 9 level 3 studies, and 2 level 4 studies), with 7194 runners and 6947 nonrunners, met the inclusion criteria. The mean follow-up time was 55.8 months in the runner group and 99.7 months in the nonrunner group. The mean age was 56.2 years in the runner group and 61.6 years in the nonrunner group. The overall percentage of men was 58.5%. There was a significantly higher prevalence of knee pain in the nonrunner group (P < .0001). Although 1 study found a significantly higher prevalence of osteophytes in the tibiofemoral (TF) and patellofemoral (PF) joints within the runner group, multiple studies found no significant differences in the prevalence of radiographic knee OA (based on TF/PF joint-space narrowing or Kellgren-Lawrence grade) or cartilage thickness on MRI between runners and nonrunners (P > .05). One study found a significantly higher risk of knee OA progressing to total knee replacement among nonrunners (4.6% vs 2.6%; P = .014).

Conclusion

In the short term, running is not associated with worsening PROs or radiological signs of knee OA and may be protective against generalized knee pain.

Osteoarthritis: New Insight on Its Pathophysiology

Understanding of the basis of osteoarthritis (OA) has seen some interesting advancements in recent years. It has been observed that cartilage degeneration is preceded by subchondral bone lesions, suggesting a key role of this mechanism within the pathogenesis and progression of OA, as well as the formation of ectopic bone and osteophytes. Moreover, low-grade, chronic inflammation of the synovial lining has gained a central role in the definition of OA physiopathology, and central immunological mechanisms, innate but also adaptive, are now considered crucial in driving inflammation and tissue destruction. In addition, the role of neuroinflammation and central sensitization mechanisms as underlying causes of pain chronicity has been characterized. This has led to a renewed definition of OA, which is now intended as a complex multifactorial joint pathology caused by inflammatory and metabolic factors underlying joint damage. Since this evidence can directly affect the definition of the correct therapeutic approach to OA, an improved understanding of these pathophysiological mechanisms is fundamental. To this aim, this review provides an overview of the most updated evidence on OA pathogenesis; it presents the most recent insights on the pathophysiology of OA, describing the interplay between immunological and biochemical mechanisms proposed to drive inflammation and tissue destruction, as well as central sensitization mechanisms. Moreover, although the therapeutic implications consequent to the renewed definition of OA are beyond this review scope, some suggestions for intervention have been addressed.

Osteoarthritis Risks and Sports: An Evidence-based Systematic Review

PURPOSE

Regular sports activities are associated with multiple physical and psychological health benefits. However, sports also may lead to injuries and the development of osteoarthritis (OA). This systematic review investigated the association between sports activity, sports type, and the risk of developing OA.

METHODS

A systematic review was performed by assessing studies that have investigated the risk of OA development in sports. Data extracted included general information, study design, number of participants, related body mass index, sports type, and assessment of OA. The methodological quality of the studies was assessed using the Newcastle-Ottawa Scale.

RESULTS

A total of 63 studies were included in this systematic review. The overall Newcastle-Ottawa Scale score was 6.46±1.44 demonstrating a good methodological quality of the articles included in the present study. A total of 628,036 participants were included, with a mean follow-up of 8.0±8.4 years. The mean age of the included athletes was 45.6±15.8, with a mean body mass index of 24.9±2.3 kg/m 2 .

CONCLUSION

Football and soccer players seem to be at higher risk for the development of OA, although the injury status of the joint should be considered when assessing the risk of OA. High equipment weight and increased injury risk also put military personnel at a higher risk of OA, although elite dancing leads to more hip labral tears. Femoroacetabular impingement was also often diagnosed in ice-hockey players and ballet dancers.

The Association Between Sex and Osteoarthritis in the Physically Active Population: A Systematic Review

PURPOSE

Intense sporting activity and certain types of work increase the risk of early osteoarthritis (OA). OA can be idiopathic or associated to certain predisposing factors: female sex, obesity, history of joint injury, and joint overuse. The role of gender among the active population as a predisposing factor for OA is not well clear. This study investigated whether the risk of OA changes with age in both sexes in physically active individuals.

MATERIALS AND METHODS

This systematic review was conducted according to the PRISMA guidelines 2020. PubMed, Google Scholar, Embase, and Web of Science databases were accessed in April 2021. No time constrains were used for the search. All the published clinical studies reporting data about relationship between physical activity and OA were included.

RESULTS

Data from 7 articles were retrieved including 360,053 patients (271,903 males; 88,150 females). The mean age was 48.2±16.7 years. Males, under the age of 60 had a higher risk of developing OA. People undertaking intense physical activity, such as professional athletes or heavy workers, are more prone to develop early OA.

CONCLUSION

Physically active males demonstrated a higher risk of developing OA.

Effect of Platelet-Rich Plasma on Autologous Chondrocyte Implantation for Chondral Defects: Results Using an In Vivo Rabbit Model

Background:

Articular cartilage repair remains challenging despite the availability of techniques, including autologous chondrocyte implantation (ACI) for repairing large cartilage defects. Platelet-rich plasma (PRP) therapy, a novel therapy focused on chondrocyte regeneration, needs to be investigated regarding its potential to improve the outcomes of ACI.

Purpose:

To examine the effect of PRP therapy on the outcomes of cartilage repair using the ACI procedure in a rabbit model of knee joint cartilage damage.

Study Design:

Controlled laboratory study.

Methods:

A total of 30 knees in 15 Japanese White rabbits (joint cartilage damage model) were divided into nontreatment (n = 7), PRP (n = 8), ACI (n = 7), and combined ACI and PRP (n = 8) groups. At 4 weeks and 12 weeks postoperatively, histological and visual examination of the surgical site was performed, and the regenerated cartilage and calcified bone areas were measured by imaging the specimens.

Results:

Pretransplantation evaluation in the cultured cartilage showed the histological properties of hyaline cartilage. At 4 weeks postoperatively, the regenerated cartilage area at the surgical site showed a larger safranin O–positive area in the ACI group (2.73 ± 4.46 mm²) than in the combined ACI and PRP group (1.71 ± 2.04 mm²). Calcified bone formation in the ACI group was relatively lower than that in the other groups. Cartilage repair failure occurred in all groups at 12 weeks postoperatively.

Conclusion:

The authors found no positive effects of PRP on the outcomes of ACI in a rabbit model. There was a smaller safranin O–positive region with the addition of PRP to ACI compared with ACI alone. In the subchondral bone, bone formation might have been promoted by PRP.

Clinical Relevance:

Administering PRP at the time of ACI may not have a positive effect and may have deleterious effects on cartilage engraftment and regeneration.

Visual Evaluation of Image Quality of a Low Dose 2D/3D Slot Scanner Imaging System Compared to Two Conventional Digital Radiography X-ray Imaging Systems

The purpose of this study was to assess the image quality of the low dose 2D/3D slot scanner (LDSS) imaging system compared to conventional digital radiography (DR) imaging systems. Visual image quality was assessed using the visual grading analysis (VGA) method. This method is a subjective approach that uses a human observer to evaluate and optimise radiographic images for different imaging technologies. Methods and materials: ten posterior-anterior (PA) and ten lateral (LAT) images of a chest anthropomorphic phantoms and a knee phantom were acquired by an LDSS imaging system and two conventional DR imaging systems. The images were shown in random order to three (chest) radiologists and three experienced (knee) radiographers, who scored the images against a number of criteria. Inter- and intraobserver agreement was assessed using Fleiss’ kappa and weighted kappa. Results: the statistical comparison of the agreement between the observers showed good interobserver agreement, with Fleiss’ kappa coefficients of 0.27–0.63 and 0.23–0.45 for the chest and knee protocols, respectively. Comparison of intraobserver agreement also showed good agreement with weighted kappa coefficients of 0.27–0.63 and 0.23–0.45 for the chest and knee protocols, respectively. The LDSS imaging system achieved significantly higher VGA image quality compared to the DR imaging systems in the AP and LAT chest protocols (p < 0.001). However, the LDSS imaging system achieved lower image quality than one DR system (p ≤ 0.016) and equivalent image quality to the other DR systems (p ≤ 0.27) in the knee protocol. The LDSS imaging system achieved effective dose savings of 33–52% for the chest protocol and 30–35% for the knee protocol compared with DR systems. Conclusions: this work has shown that the LDSS imaging system has the potential to acquire chest and knee images at diagnostic quality and at a lower effective dose than DR systems.

Tibiofemoral Cartilage Contact Pressures in Athletes During Landing: A Dynamic Finite Element Study

Cartilage defects are common in the knee joint of active athletes and remain a problem as a strong risk factor for osteoarthritis. We hypothesized that landing during sport activities, implication for subfailure ACL loading, would generate greater contact pressures (CP) at the lateral knee compartment. The purpose of this study is to investigate tibiofemoral cartilage CP of athletes during landing. Tibiofemoral cartilage contact pressures (TCCP) under clinically relevant anterior cruciate ligament subfailure external loadings were predicted using four dynamic explicit finite element (FE) models (2 males and 2 females) of the knee. Bipedal landing from a jump for five cases of varying magnitudes of external loadings (knee abduction moment, internal tibial torque, and anterior tibial shear) followed by an impact load were simulated. Lateral TCCP from meniscus (area under meniscus) and from femur (area under femur) increased by up to 94% and %30 respectively when external loads were incorporated with impact load in all the models compared to impact-only case. In addition, FE model predicted higher CP in lateral compartment by up to 37% (11.87 MPa versus 8.67 MPa) and 52% (20.19 MPa versus 13.29 MPa) for 90% and 50% percentile models, respectively. For the same percentile populations, CPs were higher by up to 25% and 82% in smaller size models than larger size models. We showed that subfailure ACL loadings obtained from previously conducted in vivo study led to high pressures on the tibiofemoral cartilage. This knowledge is helpful in enhancing neuromuscular training for athletes to prevent cartilage damage.

Association of Sports Participation With Osteoarthritis: A Systematic Review and Meta-Analysis

Background:

The association between participating in sport and osteoarthritis is not fully understood.

Purpose:

To investigate the association between osteoarthritis and participating in sports not listed in previous reviews: American football, archery, baseball, bobsleigh, curling, handball, ice hockey, shooting, skeleton, speed skating, and wrestling.

Study Design:

Systematic review; Level of evidence, 3.

Methods:

We searched 4 electronic databases and hand searched recent/in-press editions of relevant journals. The criteria for study selection were case-control studies, cohort studies, nested case-control studies, and randomized trials with a control group that included adults to examine the effect of exposure to any of the included sports on the development of osteoarthritis.

Results:

The search returned 6197 articles after deduplication. Nine studies were included in the final review, covering hip, knee, and ankle osteoarthritis. There were no studies covering archery, baseball, skeleton, speed skating, or curling. The 6 sports included in the review were analyzed as a collective; the results of the meta-analysis indicated that participation in the sports analyzed was associated with an increased risk of developing osteoarthritis of the hip (relative risk [RR] = 1.67 [95% confidence interval (CI), 1.15-2.41]; P = .04), knee (RR = 1.60 [95% CI, 1.23-2.08]; P < .001), and ankle (RR = 7.08 [95% CI, 1.24-40.51]; P = .03) as compared with controls. Meta-analysis suggested a significantly increased likelihood of developing hip osteoarthritis through participating in wrestling (RR = 1.78 [95% CI, 1.20-2.64]; P = .004) and ice hockey (RR = 1.70 [95% CI, 1.27-2.29]; P < .001), while there was no significant difference through participating in handball (RR = 2.50 [95% CI, 0.85-7.36]; P = .10). Likelihood of developing knee osteoarthritis was significantly increased in wrestling (RR = 2.22 [95% CI, 1.59-3.11]) and ice hockey (RR = 1.52 [95% CI, 1.18-1.96]; both P < .002). According to the meta-analysis, shooting did not have a significant effect on the RR of knee osteoarthritis as compared with other sports (RR = 0.43 [95% CI, 0.06-2.99]; P = .39).

Conclusion:

The likelihood of developing hip and knee osteoarthritis was increased for ice hockey and wrestling athletes, and the risk of developing hip osteoarthritis was increased for handball athletes. The study also found that participation in the sports examined, as a collective, resulted in an increased risk of developing hip, knee, and ankle osteoarthritis.

The Risk of Knee Osteoarthritis in Professional Soccer Players—a Systematic Review With Meta-Analyses

BACKGROUND

We address the question whether professional soccer players with and without macroinjury of the knee joint are at an elevated risk for knee osteoarthritis.

METHODS

A systematic review with meta-analyses was conducted. The study protocol was prospectively registered (registration number CRD42019137139). The MEDLINE, EMBASE, and Web of Science databases were searched for relevant publications; in addition, forward searching was performed, and the listed references were considered. All steps of the process were undertaken independently by two reviewers, and any discordances were resolved by consensus. For all publications whose full text was included, the methods used were critically evaluated. The quality of the evidence was judged using the GRADE criteria.

RESULTS

The pooled odds ratio for objectively ascertained osteoarthrosis of the knee was 2.25 (95% confidence interval [1.41-3.61], I2 = 71%). When only radiologically ascertained knee osteoarthrosis was considered, the odds ratio was 3.98 [1.34; 11.83], I2 = 58%). The pooled risk estimator in studies in which knee joint macroinjury was excluded was 2.81 ([1.25; 6.32], I2 = 71%).

CONCLUSION

A marked association was found between soccer playing and knee osteoarthritis in male professional soccer players. For female professional soccer players, the risk of knee osteoarthritis could not be assessed because of the lack of data. Knee injuries seem to play an important role in the development of knee osteoarthritis in professional soccer players.

The association of the progression of knee osteoarthritis with high-sensitivity CRP in community-dwelling people-the Yakumo study

OBJECTIVE

We aimed to investigate the relationship between high-sensitivity CRP (hs-CRP) levels and the knee osteoarthritis (KOA) status and whether high hs-CRP levels predict the progression of clinical KOA in community-dwelling people.

METHODS

We enrolled 247 subjects (male, n = 99; female, n = 148) who participated in the "Yakumo study" at least twice from 2003 to 2008. The KOA was evaluated by knee X-ray using the knee osteoarthritis computer-aided diagnosis (KOACAD) measurement system to obtain the mJSW, the size of the osteophyte area (OPA), and femorotibial angle (FTA). The pain intensity of the knee joint was measured using a visual analog scale (VAS, 0-100). First, we performed a multiple regression analysis to assess the relationship between the initial hs-CRP and mJSW, OPA, FTA, and VAS. Second, we examined the correlated coefficients between the amount of change hs-CRP and radiographic progressions and VAS changes. Third, we divided into two groups. Group H elevated hs-CRP levels (> 0.1 mg/dl). We picked up the subject matched to Group H according to BMI, age, sex, and medial mJSW at baseline in a 1:1 ratio; these participants were classified as the control group (Group L). The Mann-Whitney U test was used to compare the demographic data between the two groups. P values of < 0.05 were considered to indicate statistical significance.

RESULTS

The initial hs-CRP was a significant explanatory factor for mJSW and VAS change in multiple regression analysis. The change of VAS value negatively correlated with the change of hs-CRP. Besides, the change of hs-CRP did not correlate with the radiographical change. Among these subjects, 55 had elevated hs-CRP levels (> 0.1 mg/dl) (Group H). Among the 192 subjects whose hs-CRP levels were ≤ 0.1 mg/dl, 55 subjects were matched to patients in Group H according to the age, sex, BMI, and average minimum joint space width (mJSW) at baseline and were used as a control group (Group L). The narrowing of the medial mJSW and the amount of change in OPA in group H were significantly greater than group L. The amount of change in FTA and VAS scores did not differ between the two groups.

CONCLUSION

Hs-CRP levels would be significantly associated with the progression of knee osteoarthritis. Key Points • We investigated the relationship between hs-CRP levels and the progression and the pain of osteoarthritis knee. • We used a KOACAD system, which can measure the medial and lateral joint space narrowing, osteophyte, and femoral-tibia angle from plain radiographs automatically. • Hs-CRP levels were significantly associated with the progression of knee osteoarthritis.

The effect of running on knee joint cartilage: A systematic review and meta-analysis

OBJECTIVE

Although running causes inevitable stress to the joints, data regarding its effect on the cartilage of the knee are conflicting. This systematic review and meta-analysis aimed to evaluate the effect of running on knee joint cartilage.

METHODS

PubMed, EMBASE, SportDiscus, and Cochrane Library databases were searched to identify randomized controlled trials (RCTs) and cohort studies. The outcome indicators were cartilage oligomeric matrix protein (COMP), cartilage volume and thickness, and T2.

RESULTS

A total of two RCTs and 13 cohort studies were included. There was no significant difference in cartilage volume between the running and control groups (MD, -115.88 U/I; 95% CI, -320.03 to 88.27; p = 0.27). However, running would decrease cartilage thickness (MD, -0.09 mm; 95%CI, -0.18 to -0.01; p = 0.03) and T2 (MD, -2.78 ms; 95% CI, -4.12 to -1.45; p < 0.001). Subgroup analysis demonstrated that COMP immediately or at 0.5 h after running was significantly increased, but there were no significant changes at 1 h or 2 h.

CONCLUSIONS

Running has advantages in promoting nutrition penetrating into the cartilage as well as squeezing out the metabolic substance, such as water. Our study found that running had a short-term adverse effect on COMP and did not affect cartilage volume or thickness.

Preconditioning of mesenchymal stromal cells with low-intensity ultrasound: influence on chondrogenesis and directed SOX9 signaling pathways

Background

Continuous low-intensity ultrasound (cLIUS) facilitates the chondrogenic differentiation of human mesenchymal stromal cells (MSCs) in the absence of exogenously added transforming growth factor-beta (TGFβ) by upregulating the expression of transcription factor SOX9, a master regulator of chondrogenesis. The present study evaluated the molecular events associated with the signaling pathways impacting SOX9 gene and protein expression under cLIUS.

Methods

Human bone marrow-derived MSCs were exposed to cLIUS stimulation at 14 kPa (5 MHz, 2.5 Vpp) for 5 min. The gene and protein expression of SOX9 was evaluated. The specificity of SOX9 upregulation under cLIUS was determined by treating the MSCs with small molecule inhibitors of select signaling molecules, followed by cLIUS treatment. Signaling events regulating SOX9 expression under cLIUS were analyzed by gene expression, immunofluorescence staining, and western blotting.

Results

cLIUS upregulated the gene expression of SOX9 and enhanced the nuclear localization of SOX9 protein when compared to non-cLIUS-stimulated control. cLIUS was noted to enhance the phosphorylation of the signaling molecule ERK1/2. Inhibition of MEK/ERK1/2 by PD98059 resulted in the effective abrogation of cLIUS-induced SOX9 expression, indicating that cLIUS-induced SOX9 upregulation was dependent on the phosphorylation of ERK1/2. Inhibition of integrin and TRPV4, the upstream cell-surface effectors of ERK1/2, did not inhibit the phosphorylation of ERK1/2 and therefore did not abrogate cLIUS-induced SOX9 expression, thereby suggesting the involvement of other mechanoreceptors. Consequently, the effect of cLIUS on the actin cytoskeleton, a mechanosensitive receptor regulating SOX9, was evaluated. Diffused and disrupted actin fibers observed in MSCs under cLIUS closely resembled actin disruption by treatment with cytoskeletal drug Y27632, which is known to increase the gene expression of SOX9. The upregulation of SOX9 under cLIUS was, therefore, related to cLIUS-induced actin reorganization. SOX9 upregulation induced by actin reorganization was also found to be dependent on the phosphorylation of ERK1/2.

Conclusions

Collectively, preconditioning of MSCs by cLIUS resulted in the nuclear localization of SOX9, phosphorylation of ERK1/2 and disruption of actin filaments, and the expression of SOX9 was dependent on the phosphorylation of ERK1/2 under cLIUS.

Electronic supplementary material

The online version of this article (10.1186/s13287-019-1532-2) contains supplementary material, which is available to authorized users.

Using Cartilage MRI T2-Mapping to Analyze Early Cartilage Degeneration in the Knee Joint of Young Professional Soccer Players

OBJECTIVE

To evaluate and characterize the appearance of articular cartilage in the tibiofemoral joint of young professional soccer players using T2-relaxation time evaluation on magnetic resonance imaging (MRI).

DESIGN

In this study, we included 57 male adolescents from the youth academy of a professional soccer team. The MRI scans were acquired of the knee joint of the supporting leg. An "early unloading" (minute 0) and "late unloading" (minute 28) T2-sequence was included in the set of images. Quantitative T2-analysis was performed in the femorotibial joint cartilage in 4 slices with each 10 regions of interest (ROIs). Statistical evaluation, using Wilcoxon signed-rank tests, was primarily performed to compare the T2 values of the "early unloading" and "late unloading."

RESULTS

When comparing "early unloading" with "late unloading," our findings showed a significant increase of T2-relaxation times in the weightbearing femoral cartilage of the medial (P < 0.001) and lateral (P < 0.001) compartment of the knee and in the tibial cartilage of the medial compartment (P < 0.001).

CONCLUSION

In this study, alterations of the cartilage were found with a maximum in the medial condyle where the biomechanical load of the knee joint is highest, as well as where most of the chronic cartilage lesions occur. To avoid chronic damage, special focus should be laid on this region.

Knee osteoarthritis risk is increased 4-6 fold after knee injury - a systematic review and meta-analysis

OBJECTIVE

To estimate knee osteoarthritis (OA) risk following anterior cruciate ligament (ACL), meniscus or combined ACL and meniscus injury.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE, Embase, SPORTDiscus, CINAHL and Web of Science until November 2018.

ELIGIBILITY CRITERIA FOR SELECTING STUDIES

Prospective or retrospective studies with at least 2-year follow-up including adults with ACL injury, meniscal injury or combined injuries. Knee OA was defined by radiographs or clinical diagnosis and compared with the contralateral knee or non-injured controls.

STUDY APPRAISAL AND SYNTHESIS

Risk of bias was assessed using the SIGN50 checklist. ORs for developing knee OA were estimated using random effects meta-analysis.

RESULTS

53 studies totalling ∼1 million participants were included: 185 219 participants with ACL injury, mean age 28 years, 35% females, 98% surgically reconstructed; 83 267 participants with meniscal injury, mean age 38 years, 36% females, 22% confirmed meniscectomy and 73% unknown; 725 362 participants with combined injury, mean age 31 years, 26% females, 80% treated surgically. The OR of developing knee OA were 4.2 (95% CI 2.2 to 8.0; I²=92%), 6.3 (95% CI 3.8 to 10.5; I²=95%) and 6.4 (95% CI 4.9 to 8.3; I²=62%) for patients with ACL injury, meniscal injury and combined injuries, respectively.

CONCLUSION

The odds of developing knee OA following ACL injury are approximately four times higher compared with a non-injured knee. A meniscal injury and a combined injury affecting both the ACL and meniscus are associated with six times higher odds compared with a non-injured knee. Large inconsistency (eg, study design, follow-up period and comparator) and few high-quality studies suggest that future studies may change these estimates.

CLINICAL RELEVANCE

Patients sustaining a major knee injury have a substantially increased risk of developing knee OA, highlighting the importance of knee injury prevention programmes and secondary prevention strategies to prevent or delay knee OA development.PROSPERO registration number CRD42015016900.

Semitendinosus autograft augmentation after bilateral patellar tendon re-rupture: a case report and technique note

BACKGROUND

Acute bilateral patellar tendon rupture is a rare occurrence, especially in young patients in the absence of comorbidities. We describe a case of bilateral patellar tendon re-rupture in a young patient without predisposing factors. Further, we explain a technique for autograft augmented patellar tendon repair with bidirectional fixation using an ipsilateral semitendinosus graft in transosseous patellar and tibia bone tunnels.

CASE PRESENTATION

We present the case of a 40-year-old healthy worker with bilateral acute on chronic patellar tendon rupture maintained following initial trauma and Krackow repair 2 years ago. He underwent bilateral reconstruction using semitendinosus autograft. At 1 year postoperatively, he has maintained the full range of motion and strength without re-rupture.

CONCLUSION

This is the first case describing a new fixation technique after bilateral patellar tendon re-rupture. The use of semitendinosus autograft for reconstruction of the patellar tendon after re-rupture is a viable and effective option.

Quadriceps muscle weakness is related to increased risk of radiographic knee OA but not its progression in both women and men: the Matsudai Knee Osteoarthritis Survey

PURPOSE

The purpose of this study was to investigate the causal relationship between quadriceps muscle strength and radiographic knee osteoarthritis (OA) in a longitudinal study.

METHODS

The present study included 976 knees from 488 subjects who participated in both the 5th (2007) and 7th (2013) surveys of the Matsudai Knee Osteoarthritis Survey. Bilateral quadriceps strengths of each subject were measured using the quadriceps training machine (QTM-05F, Alcare Co., Ltd., Tokyo, Japan). Additionally, weight-bearing standing knee radiographs were obtained, and knee OA was graded according to the Kellgren-Lawrence classification system. The relationships between quadriceps strength and the incidence and progression of radiographic knee OA were assessed using multiple logistic regression analysis.

RESULTS

After adjusting for age and body mass index (BMI), both female and male knees in the lowest quantile of quadriceps strength had higher risk of the incidence of radiographic knee OA compared with the highest quantile of quadriceps strength (women: OR 2.414, 95% CI 1.098-5.311; men: OR 2.774, 95% CI 1.053-7.309). In contrast, after adjusting for age, BMI and femorotibial angle, both female and male knees in the lowest quantile compared with the highest quantile of quadriceps strength did not differ in risk of the progression of radiographic knee OA (women: OR 1.040, 95% CI 0.386-2.802; men: OR 2.814, 95% CI 0.532-14.898).

CONCLUSION

Quadriceps muscle weakness was related to increased risk of the incidence of radiographic knee OA, but not its progression, in both women and men. Therefore, the clinically important finding of this study is that, in both women and men, maintaining higher quadriceps muscle strength may be one of the most effective prevention methods for incident radiographic knee OA.

LEVEL OF EVIDENCE

II.

MRI-Detected Sports-Related Knee Injuries and Abnormalities at the Rio de Janeiro 2016 Summer Olympic Games

OBJECTIVE

The purpose of this article is to describe knee abnormalities and the occurrence of MRI-detected sports-related knee abnormalities by evaluating MRI examinations performed during the Rio de Janeiro Olympic Games held in August 2016.

CONCLUSION

There were 11,274 athletes at the Rio 2016 Olympic Games, and 113 of them underwent at least one knee MRI in the Olympic Village. Cartilage abnormalities, followed by meniscal tears and ligament sprains, were the most frequent abnormalities.

Physical activity in former elite cricketers and strategies for promoting physical activity after retirement from cricket: a qualitative study

OBJECTIVES

The health benefits of professional sport dissipate after retirement unless an active lifestyle is adopted, yet reasons for adopting an active or inactive lifestyle after retirement from sport are poorly understood. Elite cricket is all-encompassing, requiring a high volume of activity and unique physical demands. We aimed to identify influences on physical activity behaviours in active and insufficiently active former elite cricketers and provide practical strategies for promoting physical activity after cricket retirement.

DESIGN

18 audio-recorded semistructured telephone interviews were performed. An inductive thematic approach was used and coding was iterative and data-driven facilitated by NVivo software. Themes were compared between sufficiently active and insufficiently active participants.

SETTING

All participants formerly played professional cricket in the UK.

PARTICIPANTS

Participants were male, mean age 57±11 (range 34-77) years, participated in professional cricket for 12±7 seasons and retired on average 23±9 years previously. Ten participants (56%) were classified as sufficiently active according to the UK Physical Activity Guidelines (moderate-intensity activity ≥150 min per week or vigorous-intensity activity ≥75 min per week). Eight participants did not meet these guidelines and were classified as insufficiently active.

RESULTS

Key physical activity influences were time constraints, habit formation, intrinsic and extrinsic motivation, physical activity preferences, pain/physical impairment and cricket coaching. Recommendations for optimising physical activity across the lifespan after cricket retirement included; prioritise physical activity, establish a physical activity plan prior to cricket retirement and don't take a break from physical activity, evaluate sources of physical activity motivation and incorporate into a physical activity plan, find multiple forms of satisfying physical activity that can be adapted to accommodate fluctuations in physical capabilities across the lifespan and coach cricket.

CONCLUSIONS

Physically active and less active retired cricketers shared contrasting attributes that informed recommendations for promoting a sustainable, physically active lifestyle after retirement from professional cricket.

Common attributes in retired professional cricketers that may enhance or hinder quality of life after retirement: a qualitative study

OBJECTIVES

Retired professional cricketers shared unique experiences and may possess specific psychological attributes with potential to influence quality of life (QOL). Additionally, pain and osteoarthritis can be common in retired athletes which may negatively impact QOL. However, QOL in retired athletes is poorly understood. This study explores the following questions from the personal perspective of retired cricketers: How do retired cricketers perceive and experience musculoskeletal pain and function in daily life? Are there any psychological attributes that might enhance or hinder retired cricketers' QOL?

DESIGN

A qualitative study using semistructured interviews, which were subject to inductive, thematic analysis. A data-driven, iterative approach to data coding was employed.

SETTING

All participants had lived and played professional cricket in the UK and were living in the UK or abroad at the time of interview.

PARTICIPANTS

Eighteen male participants, aged a mean 57±11 (range 34-77) years had played professional cricket for a mean 12±7 seasons and had been retired from professional cricket on average 23±9 years.

RESULTS

Fifteen participants reported pain or joint difficulties and all but one was satisfied with their QOL. Most retired cricketers reflected on experiences during their cricket career that may be associated with the psychological attributes that these individuals shared, including resilience and a positive attitude. Additional attributes included a high sense of body awareness, an ability to self-manage pain and adapt lifestyle choices to accommodate physical limitations. Participants felt fortunate and proud to have played professional cricket, which may have further contributed to the high QOL in this group of retired cricketers.

CONCLUSIONS

Most retired cricketers in this study were living with pain or joint difficulties. Despite this, all but one was satisfied or very satisfied with their QOL. This may be partly explained by the positive psychological attributes that these retired cricketers shared.

The Association of Recreational and Competitive Running With Hip and Knee Osteoarthritis: A Systematic Review and Meta-analysis

Study Design Systematic review and meta-analysis. Background Running is a healthy and popular activity worldwide, but data regarding its association with osteoarthritis (OA) are conflicting. Objectives To evaluate the association of hip and knee OA with running and to explore the influence of running intensity on this association. Methods PubMed, Embase, and Cochrane Library databases were used to identify studies investigating the occurrence of OA of the hip and/or knee among runners. A meta-analysis of studies comparing this occurrence between runners and controls (sedentary, nonrunning individuals) was conducted. Runners were regarded as "competitive" if they were reported as professional/elite athletes or participated in international competitions. Recreational runners were individuals running in a nonprofessional (amateur) context. The prevalence rate and odds ratio (with 95% confidence interval [CI]) for OA between runners (at competitive and recreational levels) and controls were calculated. Subgroup analyses were conducted for OA location (hip or knee), sex, and years of exposure to running (less or more than 15 years). Results Twenty-five studies (n = 125810 individuals) were included and 17 (n = 114829 individuals) were meta-analyzed. The overall prevalence of hip and knee OA was 13.3% (95% CI: 11.6%, 15.2%) in competitive runners, 3.5% (95% CI: 3.4%, 3.6%) in recreational runners, and 10.2% (95% CI: 9.9%, 10.6%) in controls. The odds ratio for hip and/or knee OA in competitive runners was higher than that in recreational runners (1.34; 95% CI: 0.97, 1.86 and 0.86; 95% CI: 0.69, 1.07, respectively; controls as reference group; for difference, P<.001). Exposure to running of less than 15 years was associated with a lower association with hip and/or knee OA compared with controls (OR = 0.6; 95% CI: 0.49, 0.73). Conclusion Recreational runners had a lower occurrence of OA compared with competitive runners and controls. These results indicated that a more sedentary lifestyle or long exposure to high-volume and/or high-intensity running are both associated with hip and/or knee OA. However, it was not possible to determine whether these associations were causative or confounded by other risk factors, such as previous injury. Level of Evidence Etiology/harm, level 2a. J Orthop Sports Phys Ther 2017;47(6):373-390. doi:10.2519/jospt.2017.7137.

Running and Knee Osteoarthritis: A Systematic Review and Meta-analysis

BACKGROUND

Osteoarthritis (OA) is a chronic condition characterized by pain, impaired function, and reduced quality of life. A number of risk factors for knee OA have been identified, such as obesity, occupation, and injury. The association between knee OA and physical activity or particular sports such as running is less clear. Previous reviews, and the evidence that informs them, present contradictory or inconclusive findings.

PURPOSE

This systematic review aimed to determine the association between running and the development of knee OA.

STUDY DESIGN

Systematic review and meta-analysis.

METHODS

Four electronic databases were searched, along with citations in eligible articles and reviews and the contents of recent journal issues. Two reviewers independently screened the titles and abstracts using prespecified eligibility criteria. Full-text articles were also independently assessed for eligibility. Eligible studies were those in which running or running-related sports (eg, triathlon or orienteering) were assessed as a risk factor for the onset or progression of knee OA in adults. Relevant outcomes included (1) diagnosis of knee OA, (2) radiographic markers of knee OA, (3) knee joint surgery for OA, (4) knee pain, and (5) knee-associated disability. Risk of bias was judged by use of the Newcastle-Ottawa scale. A random-effects meta-analysis was performed with case-control studies investigating arthroplasty.

RESULTS

After de-duplication, the search returned 1322 records. Of these, 153 full-text articles were assessed; 25 were eligible, describing 15 studies: 11 cohort (6 retrospective) and 4 case-control studies. Findings of studies with a diagnostic OA outcome were mixed. Some radiographic differences were observed in runners, but only at baseline within some subgroups. Meta-analysis suggested a protective effect of running against surgery due to OA: pooled odds ratio 0.46 (95% CI, 0.30-0.71). The I² was 0% (95% CI, 0%-73%). Evidence relating to symptomatic outcomes was sparse and inconclusive.

CONCLUSION

With this evidence, it is not possible to determine the role of running in knee OA. Moderate- to low-quality evidence suggests no association with OA diagnosis, a positive association with OA diagnosis, and a negative association with knee OA surgery. Conflicting results may reflect methodological heterogeneity. More evidence from well-designed, prospective studies is needed to clarify the contradictions.

Osteoarthritis in Football

Football is currently the most popular sporting activity in the world. Multiple reports have shown that a high incidence of osteoarthritis is found in football players. Evidence clearly shows that traumatic injury significantly predisposes players for such pathophysiology. Injuries are frequent in amateur as well as professional football players, with knee and ankle accounting for the most severe injuries. Many professional athletes lose playing time due to injuries and many are forced into early retirement. Posttraumatic osteoarthritis is a common finding among ex-football players with numbers well above the normal population. Today's surgical techniques are advanced and capable of restoring the joint to a certain extent. However, a restitution ad integrum is reached only in very rare cases. Professional football players that return to play after serious injuries perform their extremely strenuous activity on morphologically compromised joints. Incomplete rehabilitation and pressure to return to play after an injurious event clearly put the athlete at an even higher risk for joint degeneration. Prevention strategies, improved surgical management, strict rehabilitation, as well as future aspects such as early suppression of inflammation, personalized medicine, and predictive genomics DNA profiling are needed to reduce incidence and improve the health perspectives of football players.

Does sports participation (including level of performance and previous injury) increase risk of osteoarthritis? A systematic review and meta-analysis

BACKGROUND

To assess the relationship between sport and osteoarthritis (OA), and specifically to determine whether previous participation, in terms of level (elite or non-elite), type of sport, intensity or previous injury, was associated with OA.

METHODS

This systematic review was developed using PRISMA guidelines. Databases were searched (to May 2016). Narrative review and meta-analysis (with risk ratio (RR) and 95% CIs) approaches were undertaken where appropriate. Study quality was assessed using GRADE.

RESULTS

46 studies were included. Narratively, 31 studies reported an increased risk of OA, with 19 demonstrating an increased risk in elite athletes. There was an increased risk after sports exposure (irrespective of type; RR 1.37; 95% CI 1.14 to 1.64; 21 studies). It remained uncertain whether there was a difference in risk of OA between elite and non-elite athletes (RR 1.37; 95% CI 0.84 to 2.22; 17 studies). The risk was higher in soccer (RR 1.42; 95% CI 1.14 to 1.77; 15 studies) but lower in runners (RR 0.86; 95% CI 0.53 to 1.41; 12 studies). 9 studies showed an association with the intensity of sport undertaken and OA. 5 studies demonstrated a higher prevalence of OA following meniscectomies and anterior cruciate ligament tears. Overall, the evidence was of GRADE 'very low' quality.

CONCLUSIONS

There was very low-quality evidence to support an increased relationship between sports participation and OA in elite participants. It is unclear whether there is a difference in risk between elite and non-elite participants with further prospective studies needed to evaluate this. Pooled findings suggested that significant injuries were associated with OA in soccer players.

Effects of horizontal plyometric training volume on soccer players' performance

The aim of this study was to examine the dose response effect of strength and conditioning programmes, involving horizontally oriented plyometric exercises, on relevant soccer performance variables. Sixteen soccer players were randomly allocated to two 6-week plyometric training groups (G1 and G2) differing by imposed (twice a week) training volume. Post-training G1 (4.13%; d = 0.43) and G2 (2.45%; d = 0.53) moderately improved their horizontal countermovement jump performance. Significant between-group differences (p < 0.01) in the vertical countermovement jump for force production time (T2) were detected post-training. No significant and practical (p > 0.05, d = trivial or small) post-training improvements in sprint, change of direction ability (CODA) and horizontal arm swing countermovement jump were reported in either group. Horizontal plyometric training was effective in promoting improvement in injury prevention variables. Doubling the volume of a horizontal plyometric training protocol was shown to have no additional effect over functional aspects of soccer players' performance.

Prevalence of Knee Osteoarthritis in 100 Athletically Active Veteran Soccer Players Compared With a Matched Group of 100 Military Personnel

BACKGROUND

Although knee injuries in professional soccer (football) have been extensively studied, the prevalence of knee osteoarthritis (OA) in veteran players is not well documented.

PURPOSE

To investigate the prevalence of knee OA in retired professional soccer players in comparison with a group of athletically active military personnel.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A group of 100 veteran Greek soccer players aged 35 to 55 years (mean [±SD] age, 46.90 ± 5.9 years) were examined for knee OA and were administered the Knee injury and Osteoarthritis Outcome Score (KOOS) questionnaire. A matched group of 100 athletically active military personnel served as a comparison group.

RESULTS

The sonographic prevalence of OA was significantly higher in the veteran soccer group (52%) than in the military group (33%) (n = 200; P = .010). This difference remained significant even after excluding participants with a history of knee surgery (44.1% vs 25.3%, respectively) (n = 151; P = .010). Femoral cartilage thickness was similar between the 2 groups (P = .473), while altered knee alignment had no effect on the prevalence of OA (P = .740). With the exception of perceived pain being more prevalent in the military group, there were no other statistically significant differences between the 2 groups in KOOS values.

CONCLUSION

Veteran soccer players had a higher sonographic prevalence of knee OA but better pain scores than a matched group of athletically active military personnel.

Bilateral and unilateral vertical ground reaction forces and leg asymmetries in soccer players

The purposes of this study were to assess unilateral and bilateral vertical jump performance characteristics, and to compare the vertical ground reaction force characteristics of the impulse and landing phase of a vertical jump between the dominant and non-dominant leg in soccer players. The sample consisted of 20 male soccer players (22.80 ± 2.71 years, 1.88 ± 0.06 m, 76.47 ± 8.80 kg) who competed in the third division of the Spanish football league. Vertical jump performance was determined by testing the impulse and landing phase of a bilateral vertical jump, dominant leg vertical jump and non-dominant leg vertical jump. Significant differences (p < 0.05) between dominant and non-dominant legs were found in counter movement jump (CMJ) flight time (LA = -2.38%, d = 0.33), CMJ flight height (LA = -4.55%, d = 0.33) and CMJ speed take-off (LA = -2.91%, d = 0.42). No significant differences were found between the dominant and non-dominant leg in the F1 and F2 magnitudes during the landing phase, the time from the first contact of the foot with the ground to the production of F1, the time from the second contact of the foot with the ground to the production of F2, and the time to stabilization of the landing phase. Although differences were found between the dominant and non-dominant leg in the impulse phase of the jump, no significant differences were found between dominant and non-dominant legs in the landing phase of vertical jump variables.

Sex differences in risk and heritability estimates on primary knee osteoarthritis leading to total knee arthroplasty: a nationwide population based follow up study in Danish twins

BACKGROUND

Symptomatic knee osteoarthritis is a highly age and sex associated complex disease. Little is known about the causes behind this age and sex associated increase, or if genetic and environmental factors impacts differently by gender. Our study examined the risk and heritability of primary knee osteoarthritis leading to total knee arthroplasty and whether these differences were attributable to sex and age differences in heritability.

METHODS

All twins of known zygosity from The Danish Twin Register alive in 1997 were examined in a nationwide population based follow-up study collecting information on all twins recorded in The Danish Knee Arthroplasty from 1997 to follow-up in 2010. Our main outcomes were the cumulative incidence, probandwise concordance rates, heritability, within pair correlations in monozygotic and dizygotic twin pairs and the genetic and environmental influence estimated in models taking into account that individuals may not have had a total knee arthroplasty at follow up.

RESULTS

92,748 twins were eligible for analyses and 576 twins had a record of primary knee osteoarthritis in The Danish Knee Arthroplasty Register at follow-up comprising 358 female and 218 male twin cases. The risk increased particular after the age of 50 years displaying significant sex differences in the elderly. In the sex stratified analyses a discrete genetic component was found in females, but in males no genetic component could be detected. In both genders common and unique environmental factors were highly significant. In the sex-adjusted analysis an additive genetic component of 18 % (0; 62), a shared environmental component of 61 % (25; 97) and an individual environmental component of 21 % (6; 36) accounted for the variation in liability to primary total knee arthroplasty.

CONCLUSION

The risk of primary total knee arthroplasty increases significantly after the age of 50 years, in particular in females, displaying significant sex differences in the elderly. After sex-adjustment 82 % of the variation in liability to primary total knee arthroplasty was attributable to common and unique environmental factors; the remaining 18 % of this variation was attributable to additive genetic factors indicating a pivotal impact of environmental factors on this disease.

Extensor mechanism ruptures of the knee: differences in demographic data and long-term outcome after surgical treatment

Extensor mechanism ruptures are rare injuries. Until now, only few reports of medium or long-term outcomes have been published.

PURPOSE

The objective of this study was to quantify differences in demographic data and complications referring to patients with either quadriceps tendon ruptures (QTR) or patellar tendon (PTR) ruptures and to evaluate if complete functional restitution can be achieved after surgical treatment.

METHODS

A search was conducted through the database of our level I trauma center in order to identify all patients surgically treated for QTRs or PTRs within 15 years and with a follow-up period of at least three years. Demographic data were collected by scanning their medical records. Of all patients available for a final check-up, their outcomes were assessed using the Knee Society Clinical Rating System (KSS), the Oxford Knee Score (OKS) and the Reduced WOMAC Function Scale (rWOMAC). Furthermore, patient perception (PP) was evaluated.

RESULTS

130 patients (93 QTRs and 43 PTRs) met the inclusion criteria. 8% of the QTR- and 13% of the PTR-patients suffered wound healing disorders/septic complications. 8% in the QTR-group sustained a rerupture. 62% of all patients were available for clinical evaluation, the mean follow-up period was 10.3 years in the QTR-group and 9.0 years in the PTR-group. In both groups good to excellent outcomes were revealed. Of the KSS-Knee, the mean score value was 93.1 in the QTR-group and 91.4 in the PTR-group; KSS-Function: 89.7/96.4; OKS: 14.6/13.1; rWOMAC: 95.7/98.3; PP: 88.5/93.3. QTR-patients suffering a rerupture had a significantly worse outcome in all scores except for the KSS-Knee (p≤0.026), whereas PTR-patients with healing disorders/septic complications showed a significant inferior outcome solely in the PP-scale (p=0.02).

Is Participation in Certain Sports Associated With Knee Osteoarthritis? A Systematic Review

OBJECTIVE

  Information regarding the relative risks of developing knee osteoarthritis (OA) as a result of sport participation is critical for shaping public health messages and for informing knee-OA prevention strategies. The purpose of this systematic review was to investigate the association between participation in specific sports and knee OA.

DATA SOURCES

  We completed a systematic literature search in September 2012 using 6 bibliographic databases (PubMed; Ovid MEDLINE; Journals@Ovid; American College of Physicians Journal Club; Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Review, Database of Abstracts of Reviews of Effects; and Ovid HealthStar), manual searches (4 journals), and reference lists (56 articles).

STUDY SELECTION

  Studies were included if they met the following 4 criteria: (1) an aim was to investigate an association between sport participation and knee OA; (2) the outcome measure was radiographic knee OA, clinical knee OA, total knee replacement, self-reported diagnosis of knee OA, or placement on a waiting list for a total knee replacement; (3) the study design was case control or cohort; and (4) the study was written in English. Articles were excluded if the study population had an underlying condition other than knee OA.

DATA EXTRACTION

  One investigator extracted data (eg, group descriptions, knee OA prevalence, source of nonexposed controls).

DATA SYNTHESIS

  The overall knee-OA prevalence in sport participants (n = 3759) was 7.7%, compared with 7.3% among nonexposed controls (referent group n = 4730, odds ratio [OR] = 1.1). Specific sports with a significantly higher prevalence of knee OA were soccer (OR = 3.5), elite-level long-distance running (OR = 3.3), competitive weight lifting (OR = 6.9), and wrestling (OR = 3.8). Elite-sport (soccer or orienteering) and nonelite-sport (soccer or American football) participants without a history of knee injury had a greater prevalence of knee OA than nonexposed participants.

CONCLUSIONS

  Participants in soccer (elite and nonelite), elite-level long-distance running, competitive weight lifting, and wrestling had an increased prevalence of knee OA and should be targeted for risk-reduction strategies.

Occupational and genetic risk factors for osteoarthritis: a review

BACKGROUND

Osteoarthritis (OA) is a multifactorial disease with strong genetic and occupational components. Although published studies have described several risk factors for OA, very few studies have investigated the occupational and genetic factors that contribute to this debilitating condition.

OBJECTIVE

To describe occupational and genetic factors that may contribute to the risk of developing (OA).

METHODS

A literature search was conducted in PubMed using the search terms osteoarthritis, occupation, work, and genetics.

RESULTS

Heavy physical work load was the most common occupational risk factor for OA in several anatomical locations. Other factors include kneeling and regular stair climbing, crawling, bending and whole body vibration, and repetitive movements. Numerous studies have also shown the influence of genetic variability in the pathogenesis of OA. Genetic variants of several groups of genes e.g., cartilage extracellular matrix structural genes and the genes related to bone density have been implicated in disease pathogenesis.

CONCLUSION

This review shows that occupational factors were extensively studied in knee OA unlike OA of other anatomical regions. Although genetic association studies performed to date identified a number of risk variants, some of these associations have not been consistently replicated across different studies and populations. Therefore, more research is needed.

Measurement properties of performance-based outcome measures to assess physical function in young and middle-aged people known to be at high risk of hip and/or knee osteoarthritis: a systematic review

OBJECTIVES

To systematically appraise the evidence on measurement properties of performance-based outcome measures to assess physical function in young and middle-aged people known to be at high risk of hip and/or knee osteoarthritis (OA).

METHODS

Electronic searches were performed in MEDLINE, CINAHL, Scopus and SPORTDiscus in May 2013. Two reviewers independently rated the measurement properties using the 4-point COSMIN checklist. Best evidence synthesis was made using COSMIN quality, consistency and direction of findings and sample size.

RESULTS

Twenty of 2736 papers were eligible for inclusion and 24 different performance-based outcome measures knee or obese populations were evaluated. No tests related to hip populations were included. Twenty-five measurement properties including reliability (nine studies), construct validity (hypothesis testing) (nine studies), measurement error (three studies), structural validity (two studies), interpretability (one study) and responsiveness (one study) were evaluated. A positive rating was given to 12.5% (30/240) of all possible measurement ratings. Tests were grouped into two categories based on the population characteristics. The one-legged hop for distance, followed by the 6-m timed hop and cross over hop for distance were the best-rated tests for the knee-injured population. Whereas the 6-min walk test was the only included test for the obese population.

CONCLUSION

This review highlights the many gaps in knowledge about the measurement properties of performance-based outcome measures for young and middle-aged people known to be at high risk of hip and/or knee OA. There is a need for consensus on which outcome measures should be used and/or combined when assessing physical function in this population. Further good quality research is required.

Exercise and osteoarthritis: cause and effects

Osteoarthritis (OA) is a common chronic joint condition predominantly affecting the knee, hip, and hand joints. Exercise plays a role in the development and treatment of OA but most of the literature in this area relates to knee OA. While studies indicate that exercise and physical activity have a generally positive effect on healthy cartilage metrics, depending upon the type of the activity and its intensity, the risk of OA development does appear to be moderately increased with sporting participation. In particular, joint injury associated with sports participation may be largely responsible for this increased risk of OA with sport. Various repetitive occupational tasks are also linked to greater likelihood of OA development. There are a number of physical impairments associated with OA including pain, muscle weakness and altered muscle function, reduced proprioception and postural control, joint instability, restricted range of motion, and lower aerobic fitness. These can result directly from the OA pathological process and/or indirectly as a result of factors such as pain, effusion, and reduced activity levels. These impairments and their underlying physiology are often targeted by exercise interventions and evidence generally shows that many of these can be modified by specific exercise. There is currently little clinical trial evidence to show that exercise can alter mechanical load and structural disease progression in those with established OA, although a number of impairments, that are amenable to change with exercise, appears to be associated with increased mechanical load and/or disease progression in longitudinal studies.

Soccer-specific warm-up and lower extremity injury rates in collegiate male soccer players

CONTEXT

A number of comprehensive injury-prevention programs have demonstrated injury risk-reduction effects but have had limited adoption across athletic settings. This may be due to program noncompliance, minimal exercise supervision, lack of exercise progression, and sport specificity. A soccer-specific program described as the F-MARC 11+ was developed by an expert group in association with the Federation Internationale de Football Association (FIFA) Medical Assessment and Research Centre (F-MARC) to require minimal equipment and implementation as part of regular soccer training. The F-MARC 11+ has been shown to reduce injury risk in youth female soccer players but has not been evaluated in an American male collegiate population.

OBJECTIVE

To investigate the effects of a soccer-specific warm-up program (F-MARC 11+) on lower extremity injury incidence in male collegiate soccer players.

DESIGN

Cohort study.

SETTING

One American collegiate soccer team followed for 2 seasons.

PATIENTS OR OTHER PARTICIPANTS

Forty-one male collegiate athletes aged 18-25 years.

INTERVENTION(S)

The F-MARC 11+ program is a comprehensive warm-up program targeting muscular strength, body kinesthetic awareness, and neuromuscular control during static and dynamic movements. Training sessions and program progression were monitored by a certified athletic trainer.

MAIN OUTCOME MEASURE(S)

Lower extremity injury risk and time lost to lower extremity injury.

RESULTS

The injury rate in the referent season was 8.1 injuries per 1000 exposures with 291 days lost and 2.2 injuries per 1000 exposures and 52 days lost in the intervention season. The intervention season had reductions in the relative risk (RR) of lower extremity injury of 72% (RR = 0.28, 95% confidence interval = 0.09, 0.85) and time lost to lower extremity injury (P < .01).

CONCLUSIONS

This F-MARC 11+ program reduced overall risk and severity of lower extremity injury compared with controls in collegiate-aged male soccer athletes.

Are joint injury, sport activity, physical activity, obesity, or occupational activities predictors for osteoarthritis? A systematic review

STUDY DESIGN

Systematic review with meta-analysis.

OBJECTIVES

To identify risk factors for osteoarthritis (OA) of the knee, hip, and ankle, including joint injury, sport, physical activity, overweight/obesity, and occupational activity, in all age groups.

BACKGROUND

OA is a significant health problem worldwide, affecting up to 10% of men and 18% of women over 60 years of age. There has not been a comprehensive review examining modifiable physical risk factors associated with the onset of OA. This evidence is important to inform the physiotherapy management of individuals following onset of OA.

METHODS

Twelve electronic databases were systematically reviewed. The studies selected met the following criteria: (1) original data; (2) joint injury, sport activity, physical activity, overweight/obesity, and/or occupational activity investigated as risk factors; (3) outcomes included OA (hip, knee, and/or ankle); and (4) analytic component of study design. The data extracted included study design, years of follow-up, study population, OA definition, risk factors, and results (effect estimates reported or calculated where available). The quality of evidence was assessed based on a modified version of the Downs and Black checklist.

RESULTS

Joint injury, obesity, and occupational activity were associated with an increased risk of OA of the knee and hip. Sport and physical activity produced inconsistent findings. Joint injury was identified as a significant risk factor for knee OA (combined odds ratio = 3.8; 95% confidence interval: 2.0, 7.2) and hip OA (combined odds ratio = 5.0; 95% confidence interval: 1.4, 18.2), as was previous meniscectomy with or without anterior cruciate ligament injury for knee OA (combined odds ratio = 7.4; 95% confidence interval: 4.0, 13.7). There is a paucity of research examining risk factors associated with ankle OA; this review identified only 2 studies with this outcome.

CONCLUSION

Joint injury, obesity, and occupational activity are associated with an increased risk of knee and hip OA. Some findings remain inconclusive, including levels of physical activity and sport specificity in individuals who do not suffer an injury. Early identification of individuals at risk for OA provides an opportunity for physiotherapy management or other interventions to modify risk-related behavior. There is a need in the literature for additional high-quality studies, such as prospective cohort studies, that minimize potential bias in examining the relationship between physical risk factors and OA.

LEVEL OF EVIDENCE

Prognosis, level 2a-.

Quadriceps muscle strength and its relationship to radiographic knee osteoarthritis in Japanese elderly

BACKGROUND

Knee osteoarthritis (OA) is a multifactorial disease and strongly affected by mechanical factors. The aims of the present study were to assess validity and reliability of a new muscle strength measuring device, the Quadriceps Training Machine (QTM) and evaluate the relationship between quadriceps strength measured by QTM and radiographic knee OA by epidemiological survey.

METHODS

The isometric knee extension muscle strength of QTM was compared with BIODEX in 24 healthy adults. Then, the relationship between radiographic knee OA and quadriceps strength using QTM was investigated with 2,032 knees in 1,016 subjects by an epidemiological survey (Matsudai Knee Osteoarthritis Survey).

RESULTS

Significant correlation was observed between QTM and BIODEX (r = 0.69, 0.82). In the Matsudai Knee Osteoarthritis Survey, the prevalence of radiographic OA (grade II or higher upon Kellgren-Lawrence classification) was: 13, 36.9, 67.8, and 86.5 %, regarding women in their fifties, sixties, seventies, and eighties, respectively, and was 1.7, 13.4, 33.5, and 66.2 % regarding men, respectively. Quadriceps muscle strength declined following 50 years of age, and significant decline was observed in the their sixties and seventies. Quadriceps muscle strength of the OA group (grades II, III and IV) was significantly declined compared with that of the Non-OA group (grade-0 and I). Furthermore, the tendency of the muscle strength level to decline with the progression of knee OA grade was particularly observed between grade 0 and grade I in both men and women and between grade I and grade II in men.

CONCLUSION

The relationship between radiographic knee OA and quadriceps strength was quantitatively evaluated by an epidemiological survey, and we found a correlation between knee OA and the decline in quadriceps strength. Furthermore, it was suggested that the decline in quadriceps muscle strength may be more strongly related to the incidence of knee OA than to its progression.

Is lifelong knee joint force from work, home, and sport related to knee osteoarthritis?

Purpose. To investigate the association of cumulative lifetime knee joint force on the risk of self-reported medically-diagnosed knee osteoarthritis (OA). Methods. Exposure data on lifetime physical activity type (occupational, household, sport/recreation) and dose (frequency, intensity, duration) were collected from 4,269 Canadian men and women as part of the Physical Activity and Joint Heath cohort study. Subjects were ranked in terms of the "cumulative peak force index", a measure of lifetime mechanical knee force. Multivariable logistic regression was conducted to obtain adjusted effects for mean lifetime knee force on the risk of knee OA. Results. High levels of total lifetime, occupational and household-related force were associated with an increased in risk of OA, with odds ratio's ranging from approximately 1.3 to 2. Joint injury, high BMI and older age were related to risk of knee OA, consistent with previous studies. Conclusions. A newly developed measure of lifetime mechanical knee force from physical activity was employed to estimate the risk of self-reported, medically-diagnosed knee OA. While there are limitations, this paper suggests that high levels of total lifetime force (all domains combined), and occupational force in men and household force in women were risk factors for knee OA.

Effects of exercise and physical activity on knee osteoarthritis

Exercise is one of the most discussed and controversial nonpharmacologic management strategies for osteoarthritis (OA) of the knee. Health care providers and patients share varied and often pseudoscientific beliefs regarding the effects of exercise on knee OA formulated on outdated notions of the etiology, pathophysiology, and progression of the condition. Based on the contemporary literature, regular light to moderate physical activity has both preventive and therapeutic benefits for individuals with knee OA. Exercise regimens with strong evidence of benefit include those that focus on aerobic/cardiovascular conditioning and lower extremity strength training. Health care providers should confidently incorporate exercise recommendations into clinical management and offer patients evidence-based and individually tailored exercise prescriptions to help manage the painful and often disabling symptoms of this condition.

Rehabilitation after Articular Cartilage Repair of the Knee in the Football (Soccer) Player

BACKGROUND

Participation in football can put both male and female players at an increased risk for knee osteoarthritis. There is a higher prevalence of focal chondral defects in the knee of athletes compared to nonathletes. The management of chondral defects in the football player is complex and multifactorial.

OBJECTIVE

The aim of this study is to provide an overview of the current strategies for rehabilitation after articular cartilage repair of the knee in the football player.

DESIGN

A review of current literature and the scientific evidence for rehabilitation after articular cartilage repair of the knee.

CONCLUSIONS

Articular cartilage repair has been shown to allow return to sport but rehabilitation timescales are lengthy. Successful rehabilitation for a return to football after articular cartilage repair of the knee requires the player to be able to accept the load of the sport. This necessitates a multidisciplinary approach to rehabilitation, especially in the transition from therapy to performance care. It should be recognized that not all players will return to football after articular cartilage repair. The evidence base for rehabilitative practice after articular cartilage repair is increasing but remains sparse in areas.

UNICOMPARTMENTAL KNEE ARTHROPLASTY: CURRENT PERSPECTIVES AND TRENDS IN BRAZIL

Objective: The aim of this study was to evaluate the approaches and procedures used by Brazilian orthopedic surgeons for treating osteoarthrosis by means of unicompartmental knee arthroplasty and high tibial osteotomy of the knee. Methods: A questionnaire with 14 closed questions was developed and applied to Brazilian knee surgeons during the three days of the 43^rd Brazilian Congress of Orthopedics and Traumatology. Results: A total of 113 surgeons filled out the questionnaire completely and became part of the sample analyzed. In this study, the majority of the surgeons performed fewer than five unicompartmental knee arthroplasty procedures/year (61.1%) and between 5 and 15 high tibial osteotomy procedures/year (37.2%). Use of computerized navigation systems during surgery remains uncommon in our environment, since only 0.9% of the specialists were using it. 65.5% of the surgeons reported that they had chosen to use total knee arthroplasty rather than partial arthroplasty due to lack of familiarity with the surgical technique. When asked about the possibility that the number of unicompartmental prostheses used in Brazil would grow as surgeons in this country become increasingly familiar with the technique, 80.5% of the respondents believed in this hypothesis. In this sample, we found that the greater the surgeon's experience was, the greater the numbers of unicompartmental prostheses and tibial osteotomies performed annually were (r = 0.550 and r = 0.465, respectively; p < 0.05). Conclusions: There is a clear evolutional trend towards treatment of unicompartmental osteoarthritis using partial knee arthroplasty in Brazil. However, further prospective controlled studies are needed in order to evaluate the clinical and scientific benefits of these trends.

Clinical and Basic Science of Cartilage Injury and Arthritis in the Football (Soccer) Athlete

Joint injuries are very common in the athletic population, especially professional soccer players, with an incidence of 10 to 35.5 injuries per 1000 hours. Most soccer-related joint injuries occur in the lower extremities, with 16% to 46% occurring in the knee and 17% to 40% occurring in the ankle. Because of the limited healing capacity of cartilage and other intra-articular soft tissue structures, such as anterior cruciate ligament (ACL) and meniscus, joint injuries often lead to the development of early disabling osteoarthritis. Osteoarthritis in soccer players is 5 to 12 times more frequent than in the general population and diagnosed 4 to 5 years earlier. It remains a major cause of disability from this sport. This review focuses on the epidemiology of soccer-related joint injuries and subsequent development of osteoarthritis in the hip, knee, and ankle joints. As well, two different pathways for pathogenesis are described: (1) primary osteoarthritis via direct trauma to the articular cartilage and (2) secondary osteoarthritis that occurs indirectly through injury to the soft tissue structures that subsequently result in articular cartilage degeneration and loss.

History of knee injuries and knee osteoarthritis: a meta-analysis of observational studies

OBJECTIVES

Although knee injury has been implicated as a risk factor for the development of knee osteoarthritis (OA), there is great disparity in the magnitude of quantifiable risk. Our aim was to systematically review the relationship between history of knee injuries and knee OA.

METHODS

Six electronic databases were searched between August and October 2010. Relative risk estimates or odds ratio (OR) and 95% confidence intervals (95% CI) were extracted or calculated from observational studies meeting the inclusion criteria. Publication bias was determined using funnel plot and the Egger's test. Heterogeneity was examined using Cochran Q test and I(2) statistic. Random effects model was used to pool the heterogeneous results and OR was used to present the results. Subgroup analyses were performed to examine potential causes of heterogeneity.

RESULTS

Twenty-four observational studies (20,997 subjects) were included in the meta-analysis of which there were seven cohort, five cross-sectional and 12 case-control studies. The overall pooled OR was 4.20 (95% CI 3.11-5.66, I(2) = 81.0%). Association between history of knee injuries and knee OA was significantly different for specified injuries such as ligament or tendon injuries; meniscus damage or meniscectomy; and fracture of femur, knee or lower part of the leg (OR = 5.95, 95% 4.57-7.75), compared to unspecified injuries (OR = 3.12, 95% 2.17-4.50).

CONCLUSION

History of knee injury is a major risk factor for the development of knee OA irrespective of study design and definition of knee injury. As one of the few modifiable/preventable risk factors, knee injury should be part of the future prevention programme in reducing the risk of knee OA.

Body mass index and susceptibility to knee osteoarthritis: a systematic review and meta-analysis

OBJECTIVE

Excess bodyweight, expressed as increased body mass index, is associated with osteoarthritis risk, especially in weight bearing joints. However, the strength of the association was inconsistent. The study was conducted to quantitatively assess the association between body mass index and the risk of knee osteoarthritis and investigate the difference of the strength stratified by sex, study type and osteoarthritis definition.

METHODS

We used published guidelines of the Meta-analysis of Observational Studies in Epidemiology Group (MOOSE) to perform the meta-analysis. The search strategy employed included computerized bibliographic searches of MEDLINE, PubMed, EMBASE, The Cochran Library and references of published manuscripts. Study-specific incremental estimates were standardized to determine the risk of knee osteoarthritis associated with a 5 kg/m(2) increase in BMI.

RESULTS

Twenty-one studies were included in the study. The results showed that body mass index was significantly positive associated with osteoarthritis risk in knee site. A 5-unit increase in body mass index was associated with an 35% increased risk of knee osteoarthritis (RR: 1.35; 95%CI: 1.21, 1.51). Magnitude of the association was significantly stronger in women than that in men with significant difference (men, RR: 1.22; 95%CI: 1.19, 1.25; women, RR: 1.38; 95%CI: 1.23, 1.54; p=0.04). The summary effect size was 1.25(95%CI: 1.18, 1.32) in case-control studies and 1.37 (95%CI: 1.19, 1.56) in cohort studies (p=0.28). Body mass index was positively associated with knee osteoarthritis defined by radiography and/or clinical symptom (RR: 1.25, 95%CI: 1.17, 1.35) and clinical surgery (RR: 1.54, 95%CI: 1.29, 1.83). The latter tended to be stronger than the former (p<0.01).

CONCLUSION

Increased body mass index contribute to a substantially increased risk of knee OA. The magnitude of the association varies by sex and OA definition.