By Patricia Pande, MClScPT, CSCS, CPed
Although not as common as Achilles tendinitis, peroneal tendinitis is seen in a certain group of patients with chronic ankle instability or with a cavovarus foot.1 Peroneal tendinitis presents as lateral foot pain and may also be of unknown etiology or associated with an acute inversion injury.2,3 Some authors have noted an association with impingement at the site of the fibular head in pes plano valgus and as a causative factor in peroneal tendon tear in the absence of instability of the ankle.4,5 For the purposes of this article, peroneal or fibular tendinopathy will be defined as any form of peroneal involvement, including tenosynovitis and tendon trauma.
Widely considered a rare injury, it is frequently missed as a source of pain after a sprain or with overuse. Some researchers estimate that peroneal tendon injuries are missed up to 40% of the time on initial evaluation of ankle pain.6 Tears of the fibularis tendon in cadavers have ranged between 11.3% and 37%7 with higher incidence increased in those with lateral ankle instability.8 Although chronic degenerative peroneal tendinopathy may be associated with anatomical variants2 there is disagreement about which anomalies are causal.9
The peroneal muscles stabilize the foot in weightbearing. The peroneus brevis everts, abducts, and plantar flexes while the peroneus longus is a primary evertor with a secondary role of plantar flexion. The peroneus longus plantar flexes the first ray and stabilizes the medial column while reinforcing ankle ligaments.10
Differential diagnosis of fibular tendinopathy includes tests to exclude ankle sprain, fracture, os trigonum syndrome, and flexor hallucis longus tendinopathy. Since ankle sprain and instability often coexist with peroneal tendinopathy, tests for ligamentous instability, syndesmotic injury, and posterior tibialis tendon involvement should be performed. Balance testing forms a baseline for treatment strategies and should be done in all patients.
Patients with peroneal tendinopathy have associated pain and tenderness on palpation of the peroneus longus or brevis, along with weakness on resisted movement. They may experience pain with overpressure into inversion, adduction, and dorsiflexion.11 Longitudinal edema along the length of the peroneal tendon typically accompanies intrasheath swelling from an acute injury.12 The block test may be administered in a patient with a cavovarus foot type and a flexible deformity.13,14
Risk factors in tennis players
Tennis is a hugely popular global sport played by people of all ages. Ankle sprains remain the most frequent injury in tennis players.15,16 Because fibularis tendon damage may occur in conjunction with ankle sprains, we can assume a risk of tendon damage during lateral movements, sudden stopping,16 or the backhand ground stroke.17,18 Recently Fong et al19 observed ankle inversion and internal rotation in side cutting as a finding concomitant with ankle injuries in tennis players.
Since the mechanism of injury may differ for the peroneus brevis versus the peroneus longus, different causative factors must be studied.18 For example, the orientation of front foot relative to the net in the tennis backhand stroke is associated with risk of ankle inversion.19
Footwear and orthoses
Footwear for peroneal or fibularis tendinopathy should be wide enough for lateral support while reducing tensile forces on the peroneal tendon.20 The prevention and treatment of foot and ankle injuries with shoe modifications has not been substantiated in the literature, however. Intuitively, medially posted footwear should be avoided in the presence of an uncompensated pes cavovarus foot.
The use of heel lifts may reduce stress on the fibularis tendon, according to Michael Gross, PT, PHD, FAPTA, a professor in the Division of Physical Therapy at the University of North Carolina at Chapel Hill.21 However, since plantar flexion may result in inversion forces associated with sprains and acute peroneal tendinopathy,12 heel lifts should be used judiciously. In tennis and other players who cut laterally, it is important to evaluate balance (both static and dynamic) in footwear rather than barefoot. Videotaping the tennis player can provide valuable information on the effects of footwear modifications.
Orthoses with lateral wedges have been prescribed for patients with recurrent ankle instability or with peroneal tendinopathy. Orthotic modification to prevent inversion sprain remains controversial and there is a paucity of data in tennis and other cutting sports.
Baur et al reported that, in 99 runners, foot orthoses were associated with enhanced peroneus longus activation during preactivation, and suggested this finding indicates an alteration in preprogrammed activity that could lead to better ankle stability.22 Orthoses with a lateral bar decreased the peak amplitude of the peroneus longus during mid to terminal stance during walking.23
Because tennis players vary greatly with regard to age and comorbidities, a multifactorial approach to orthotic management is advised. Studies suggesting that lateral wedged orthoses reduce knee moments only in conjunction with increased ankle inversion and a greater eversion moment may have relevance for athletes with both peroneal tendinopathy and knee osteoarthritis.24,25 Gross advises the use of a lateral wedge when the rearfoot has enough motion to adapt to the modification.21
Theoretically a plantar flexed first ray should cause a supinatory force at the ankle. Thus, orthotic modification for a rigid plantar flexed first ray includes either a cut out or a kinetic wedge. In the case of hallux limitus, this should include control of the lateral foot with a flange or lateral post or a deep heel cup.26 Caution must be taken to not overload medial structures.27
Peroneal tendon subluxation
Peroneal tendon subluxation may occur acutely and may coexist with fibularis tendinopathy;4 it has also been associated with chronic ankle instability.28 The most common causes are cutting and twisting movements involved in sports such as tennis and skiing. In my observation, the condition exists more often with hypermobility, and it may be associated with a shallow fibular head groove.29
Patients with peroneal subluxation may describe popping or snapping of the peroneal tendon while actively moving the foot into dorsiflexion and eversion. The patient may also experience pain and swelling, and subluxation of the tendon anterior to the lateral malleolus may be visible. Biomechanical foot problems may include a pes cavus foot, an uncompensated rearfoot varus, or an uncompensated rearfoot varus combined with a tibial varus.30 This condition is often misdiagnosed as an ankle sprain, but computed tomography, ultrasound, and other imaging modalities can be used to verify the condition.
Conservative treatment includes ice, rest or activity modification, and stretching. Although early
return to full activity has been reported when cryotherapy is applied within 36 hours of injury,31 utilization of this modality remains surprisingly low. Tape or bracing has also been used with varying results.27 Treatment incorporating strength, proprioceptive, and balance training is introduced after the early stages of healing. Proprioceptive training is believed to increase activation of the peroneus longus32 and was associated with reduced ankle sprain recurrence in Italian basketball players.33 The Italian authors suggested that improved proprioceptive control may enhance reflex contraction of protective muscles at the ankle, reducing deleterious supination of the foot.33 Their study does support the need for continued, measured analysis of the effects of proprioceptive training in ankle injuries.
Orthoses and peroneal subluxation
Research on chronic ankle instability demonstrates that orthosis use can improve balance and center of pressure;34-36 these findings can be extrapolated to the treatment plan for peroneal subluxation.34 Orthoses can be used to reduce postural sway in asymptomatic individuals and postinjury.35-39 Proprioceptive input from total contact of the orthoses may enhance stability40 and should be studied further.
Dingenen et al found increased preactivation of the peroneal muscles associated with orthoses,40 suggesting they could be used in addition to or as a substitute for bracing. The additive effect of orthoses (custom or standard) along with footwear altered the temporal characteristics of firing for the peroneus longus. Early activation during the transition from single- to double-leg stance is suspected to confer a protective effect for lateral ankle sprains.40 A lateral wedge can be used if some of the biomechanical rearfoot problems allow a degree of correction.21,24,30
Footwear and peroneal subluxation
Footwear must be wide and have torsional stability. The shoe must fit properly and be high enough to contain the foot up to the malleoli but not rub the tendons. Spacers can lift the foot, or a gel horseshoe can be placed near the tendon to offload it.
In a study of ankle kinematics and kinetics in 13 child tennis players, a decrease in shoe drop was associated with decreased impact forces during open-stance forehand shots.41 The findings cannot reliably be generalized to injuries other than those that are impact-related, but lower-drop footwear was related to an earlier onset of muscle activation of the peroneus longus, which may have some protective effect in players with recurrent ankle sprains; I have seen evidence of this effect clinically.
A balanced approach and continued research are key to current and future success in managing the perplexing conditions of peroneal tendinopathy and subluxation. Orthoses must be adaptable to the changing needs of the athlete and not worsen the problem. Gradual modification and ongoing measurement of the effect on tennis biomechanics is of paramount importance. Shoes and orthoses must complement each other to avoid increasing the risk of ankle instability. Lateral posts must be used judiciously in players with sufficient rearfoot motion and appropriate responses to the rearfoot motion. Modifiable inserts with various degrees of posting, along with a deep heel cup and flanges, should be considered; these may provide a new paradigm for a challenging problem.
Patricia Pande, MClScPT, CSCS, CPed, is a physical therapist, pedorthist, and strength and conditioning specialist based in San Diego. She is the founder of FootCentric, an online continuing education company dedicated to comprehensive multidisciplinary foot treatment.
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- DiGiovanni BF, Fraga CJ, Cohen BE, Shereff MJ. Associated injuries found in chronic lateral ankle instability. Foot Ankle Int 2000;21(10):809-815.
- Dirks SC, Warden SJ. Models for the study of tendinopathy. J Musculoskelet Neuronal Interact 2011;11(2):141-149.
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- Alexander I. The Foot: Examination and Diagnosis. Churchill Livingstone: New York; 1990.
- Franson J, Baravarian B. Lateral ankle triad: The triple injury of ankle synovitis, lateral ankle instability and peroneal tendon tear. Clin Podiatr Med Surg 2011;28(1):105-115.
- Coleman SS, Chestnut WJ. A simple test for hindfoot flexibility in the cavovarus foot. Clin Orthop Rel Res 1977;123(3):60-62.
- Iwamoto S, Kuramochi R, Fukubayashi T. Injury and practice surveillance study of Japanese high school and college tennis players. J Japan Soc Clin Sports Med 2011;119(1):36-42.
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- Babette P, Marc S. From breakpoint to advantage: A practical guide to optimal tennis health and performance. Vista, CA: Racquet Tech Pub. 2004.
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- Iwamoto S, Fukubayashi T, Hume P. Pelvic rotation and lower extremity motion with two directions in the tennis backhand groundstroke. J Sports Sci Med 2013;12(2):339-345.
- Ardizzone R, Valmassy R. How to diagnose lateral ankle injuries. Podiatry Today 2005;18(10):65-74.
- From an interview with Gross, Michael, PT, PHD, on October 1, 2016.
- Baur H, Hirschmuller A, Muller S, Mayer F. Neuromuscular activity of the peroneal muscle after foot orthoses therapy in runners. Med Sci Sports Exerc 2011;43(8):1500-1506.
- Moisan G, Cantin V. Effects of two types of foot orthoses on lower limb muscle activity before and after a one month period of wear. Gait Posture 2016;46:75-80.
- Chapman GJ , Parkes MJ, Forsythe L, et al. Ankle motion influences the external knee adduction moment and may predict who will respond to lateral wedge insoles? An ancillary analysis from the SILK trial. Osteoarthritis Cartilage 2015;23(8):1316-1322.
- Hinman RS, Bowles KA, Payne C, Bennell KL. Effect of length on laterally-wedged insoles in knee osteoarthritis. Arthritis Rheum 2008;59(1):144-147.
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- Sesma AR, Mattacola CG, Uhl TL et al. Effect of foot orthotics on single-and double-limb balance tasks in patients with chronic ankle instability. Foot Ankle Spec 2008;1(6):330-337.
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- Mattacola CG, Dwyer MK, Miller AK, et al. Effect of orthoses on postural stability in asymptomatic subjects with rearfoot malalignment during a six-week acclimation period. Arch Phys Med Rehabil 2007;88(5):653-660.
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