Research Review By Dr. Brynne Stainsby©


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Date Posted:

October 2019

Study Title:

The association of ankle dorsiflexion and dynamic knee valgus: A systematic review and meta-analysis


Lima YL, Ferreira VMLM, de Paula Lima PO et al.

Author's Affiliations:

Department of Physical Therapy, Federal University of Ceará, Fortaleza, Brazil.

Publication Information:

Physical Therapy in Sport 2018; 29: 61-69.

Background Information:

Reduced ankle dorsiflexion (ADF) has been reported to be a risk factor in conditions such as patellar and Achilles tendinopathy, chronic ankle instability and anterior knee pain (1-8). An abnormal movement pattern composed of excessive femoral adduction and internal rotation, tibial internal rotation and medial displacement of the knee, has been defined as dynamic knee valgus (DKV) (9-15). It has been hypothesized that those with restricted ADF may compensate for lack of range in the sagittal plane with movement in the frontal or transverse planes (10, 11, 13-18). Individuals may pronate the foot (14, 19), internally rotate the tibia (14), internally rotate and adduct the hip (13, 18) or ‘drop’ the pelvis (16, 17), all of which can result in DKV.

The aim of this study was to review and perform a meta-analysis of the literature related to the association of ankle dorsi flexion (ADF) in dynamic knee valgus (DKV).

Pertinent Results:

  • A total of 1617 articles were identified in the search, and 13 were ultimately included in the review (3, 9-11, 13-17, 20-23). An additional four papers were identified through the reference lists of the included studies (24, 25, 12, 18).
  • The included studies ranged from 7-9 out of 10, suggesting good methodological quality. It should be noted that no study provided sufficient information to state if the sample was representative of the entire population.
  • Due to the different forms of measurement of ADF, the data was split into subgroups and data could be included in more than one subgroup.
  • The 17 articles assessed the relationship between ADF and DKV. Each assessment was treated as an independent result, and 44 associations between ADF and knee/hip kinematics were analyzed.
  • When the findings were observed by task, five associations were assessed during double-leg squat (three found relationships), 15 associations were assessed during a lateral step down (LSD) task (11 found a relationship), six associations were evaluated during overhead squat (two found a relationship), five associations were evaluated during single leg squat (three found correlation), six associations were assessed during drop landings (two found a relationship), forward step-down (FSD) and gait were assessed once and no associations were found.
  • When the findings were assessed by ADF measurement, 13 were assessed while non-weightbearing (NWB) with the knee flexed (seven showed a relationship with DKV), 10 were assessed while NWB with knee extended (seven found a relationship) and 10 were assessed with WB position (five showed correlation).
  • The associations showed the relationship of ADF and DKV to be highly divergent, impeding qualitative synthesis from drawing conclusive assumptions.
  • Studies reporting ADF in controls and DKV groups were sub-grouped according to whether they measured ADF in NWB position with the knee flexed (n = 6 studies), NWB with the knee extended (n = 6 studies), and a WB lunge (n = 2).
  • Pooled analysis of all subgroups showed significantly lower values of ADF in the DKV groups (n = 330) compared to controls (n = 350) (SMD -0.65, 95% CI -0.88 to -0.41).
  • Medium heterogeneity was found in the pooled analysis of all subgroups, and when pooled results were analysed by subgroup, mild heterogeneity was found, thus pooled analysis was deemed to be valid. Pooled analysis showed significantly lower values for ADF in the DKV groups compared to controls (SMD -0.54, 95% CI -0.80 to -.028, subgroups NWB – knee straight) and pooled analysis for the other groups also showed significantly lower values compared to controls. The findings in the WB and NWB – knee flexed groups had medium to high within-group heterogeneity.

Clinical Application & Conclusions:

This review demonstrates evidence for an association between reduced ADF and DKV. The meta-analysis portion of this review demonstrated that reduced ADF range of motion was present in individuals presenting with DKV when compared to controls (regardless of position of ADF measurement). Although the tasks used in the included studies are considered valid and reliable in assessing movement patterns, it is difficult to understand which other factors (such as gender or other lower limb diagnoses) may affect ADF. In one of the included studies, subjects had patellofemoral pain, and as it has been reported that patients with this condition often present with faulty movement patterns and DKV, it is challenging to know the relationships between the different factors contributing to movement patterns in the lower limb (26). Future research considering factors such as neuromuscular variables, reduced knee and hip flexion angles (14), poor trunk alignment (27) and reduced gluteus maximus activation is required to understand the clinical relevance of these findings.

Overall, it is not possible to determine if reduced ADF is the cause of, or an adaptation to, DKV. While only one study (27) has been conducted to examine the influence of an intervention intended to improve ADF to reduce DKV, clinicians hoping to create injury prevention programs for lower limb injury could consider developing strategies to increase ADF and reduce DKV.

Study Methods:

  • Two researchers independently performed a search of four databases from inception to September 2016 using appropriate search terms for each database. Reference lists of included studies were screened for additional resources.
  • Two independent reviewers screened titles and abstracts for inclusion. A third reviewer was available if disagreement occurred. Full texts were obtained when necessary.
  • To be included in the review, studies must have reported the association between at least one outcome for ADF and one for kinematics of the knee and/or hip in the frontal plane and/or hip in the transverse plane in any dynamic task. Subjects in the included studies could be male or female, healthy or those with any condition in the knee. No restrictions over language or publication date were made. Studies published as full text were eligible for inclusion.
  • As there is not an established assessment tool for non-interventional studies, the scientific quality of studies was assessed using a customized checklist based on a checklist of interventional studies (Downs and Black 1998). The items were related to: description of hypothesis/objective, the main outcomes, the participants’ characteristics, findings, estimates of random variability, actual probability values, representative sample of subjects, appropriate statistical tests, valid and reliable outcome measures. Two authors assessed the methodological quality and a third reviewed any disagreements.
  • Two reviewers extracted information from the selection studies and a synthesis of data was provided.
  • A meta-analysis was performed and a random-effects model was used to calculate the standardized mean difference after the extraction of sample sizes, means and standard deviations from the articles. A qualitative synthesis was also performed.

Study Strengths / Weaknesses:

  • Independent screening of titles and abstracts, and full texts.
  • The modified checklist had previously been used in other reviews.
  • Only those trials assessed as being of high quality were included.
  • Two authors independently extracted the data from the included articles.
  • It should be noted that no study provided sufficient information to state if the sample was representative of the entire population, therefore the external validity of the evidence may be limited.
  • It should be noted that the studies in this review were heterogeneous in populations studied, the tests used, and measurement techniques.
  • Based on the methodological designs of the included studies, it is impossible to determine a causal nature in the relationship between ADF and DKV, and the results must be interpreted through that lens.
  • Many of the included studies did not reach statistical significance.

Additional References:

  1. Backman L J, Danielson P. Low range of ankle dorsiflexion predisposes for patellar tendinopathy in junior elite basketball players: A 1-year prospective study. Am J Sports Med 2011; 39: 2626-2633.
  2. Malliaras P, Cook JL, Kent P. Reduced ankle dorsiflexion range may increase the risk of patellar tendon injury among volleyball players. J Sci Med Sport 2006; 9: 304-30.
  3. Rabin A, Kozol Z & Finestone AS Limited ankle dorsiflexion increases the risk for mid-portion Achilles tendinopathy in infantry recruits: A prospective cohort study. J Foot Ankle Res 2014; 7: 48.
  4. Hoch MC, Andreatta RD, Mullineaux DR et al. Two-week joint mobilization intervention improves self-reported function, range of motion, and dynamic balance in those with chronic ankle instability. J Orthop Res 2012; 30: 1798-1804.
  5. Chuckpaiwong B, Cook C, Pietrobon R et al. Second metatarsal stress fracture in sport: Comparative risk factors between proximal and nonproximal locations. Br J Sports Med 2007; 41: 510-514.
  6. Kaufman KR, Brodine SK, Shaffer RA et al. The effect of foot structure and range of motion on musculoskeletal overuse injuries. Am J Sports Med 1999; 27: 585-593.
  7. Taunton JE & Wilkinson M. Rheumatology: 14. Diagnosis and management of anterior knee pain. Can Med Associ J 2001; 164, 1595-1601.
  8. Witvrouw E, Lysens R, Bellemans J et al. Intrinsic risk factors for the development of anterior knee pain in an athletic population. A two-year prospective study. Am J Sports Med 2000; 28: 480-489.
  9. Fong CM, Blackburn JT, Norcross MF et al. Ankle-dorsiflexion range of motion and landing biomechanics. J Athl Training 2011; 46: 5-10.
  10. Macrum E, Bell DR, Boling M et al. Effect of limiting ankle-dorsiflexion range of motion on lower extremity kinematics and muscle activation patterns during a squat. J Sport Rehabil 2012; 21: 144-150.
  11. Sigward SM, Ota S & Powers CM. Predictors of frontal plane knee excursion during a drop land in young female soccer players. J Orthop Sports Phys Ther 2008; 38: 661-667.
  12. Stiffler MR, Pennuto AP, Smith MD et al. Range of motion, postural alignment, and LESS score differences of those with and without excessive medial knee displacement. Clin J Sport Med 2015; 25: 61-66.
  13. Bell-Jenje T, Olivier B, Wood W et al. The association between loss of ankle dorsiflexion range of movement, and hip adduction and internal rotation during a step down test. Man Ther 2016; 21: 256-261.
  14. Dill KE, Begalle RL, Frank BS et al. Altered knee and ankle kinematics during squatting in those with limited weight-bearing lunge ankle-dorsiflexion range of motion. Journal of Athletic Training 2014; 49: 723-732.
  15. Mauntel TC, Begalle RL, Cram TR et al. The effects of lower extremity muscle activation and passive range of motion on single leg squat performance. J Strength Cond Res 2013; 27: 1813-1823.
  16. Rabin A & Kozol Z. Measures of range of motion and strength among healthy women with differing quality of lower extremity movement during the lateral step-down test. J Orthop Sports Phys Ther 2010; 40: 792-800.
  17. Rabin A, Kozol Z, Moran U et al. Factors associated with visually assessed quality of movement during a lateral step-down test among individuals with patellofemoral pain. J Orthop Sports Phys Ther 2014; 44: 937-946.
  18. Wyndow N, De Jong A, Rial K et al. The relationship of foot and ankle mobility to the frontal plane projection angle in asymptomatic adults. J Foot Ankle R 2016; 9: 3.
  19. Bell DR, Padua DA & Clark MA. Muscle strength and flexibility characteristics of people displaying excessive medial knee displacement. Arch Phys Med Rehabil 2008; 89: 1323-1328.
  20. Bell DR, Vesci BJ, DiStefano LJ et al. Muscle activity and flexibility in individuals with medial knee displacement during the overhead squat. Athletic Training & Sports Health Care 2012; 4: 117-125.
  21. Malloy P, Morgan A, Meinerz C et al. The association of dorsiflexion flexibility on knee kinematics and kinetics during a drop vertical jump in healthy female athletes. Knee Surg Sports Traumatol Arthrosc 2015; 23: 3550-3555.
  22. Ota S, Ueda M, Aimoto K et al. Acute influence of restricted ankle dorsiflexion angle on knee joint mechanics during gait. Knee 2014; 21: 669-675.
  23. Park KM, Cynn HS & Choung SD. Musculoskeletal predictors of movement quality for the forward step-down test in asymptomatic women. J Orthop Sports Phys Ther 2013; 43: 504-510.
  24. Rabin A, Portnoy S & Kozol Z. The association of ankle dorsiflexion range of motion with hip and knee kinematics during the lateral step down test. J Orthop Sports Phys Ther 2016b; 30(11): 1-31.
  25. Hewett TE, Myer GD, Ford KR et al. Biomechanical measures of neuromuscular control and valgus loading of the knee predict anterior cruciate ligament injury risk in female athletes: A prospective study. Am J Sports Med 2005; 33: 492-501.
  26. Cronstrom A, Creaby MW, Nae J et al. Modifiable factors associated with knee abduction during weight-bearing activities: A systematic review and meta-analysis. Sports Med 2016; 46(11): 1647-1662.
  27. Bell DR, Oates DC, Clark MA et al. Two- and 3-dimensional knee valgus are reduced after an exercise intervention in young adults with demonstrable valgus during squatting. Journal of Athletic Training 2013; 48: 442-449.