Due to the physical demands of triathlon, it is not surprising that triathletes sustain a high number of overuse injuries. Burns et al. found that during a six-month training period, 50.4% of triathletes were injured.1
This is consistent with other studies that found that 75% of injuries experienced by triathletes occurred during training and 78.9% were defined as overuse. 2
The most commonly reported injuries amongst triathletes are the ankle/foot, thigh, knee, lower leg, and the back. The frequency of lower extremity injuries is not surprising when considering the repetitive impact of weight-bearing forces associated with running and the extensive use of the lower extremities in cycling.3
Overall, the majority of injuries occurred during running training while swimming and cycling were associated with a lower numbers of injuries.1,3,4
The patient in this case report sustained an acute lower leg/ankle injury during a swimming training session which represents an uncommon mechanism of a lower limb injury for a triathlete. As previously mentioned, the incidence of swimming-related injuries is low and most of these injuries involve the shoulder.3
Injuries related to swimming that do not commonly occur in the pool may include achilles tendonopathy, gastroc/soleus muscle strains, and tibialis posterior dysfunction due the position of the ankle and foot during the swim. This shortening or tightness in the calf can increase the susceptibility of the triathlete to overstress of these lower leg tendons.3
The tibialis posterior muscle originates on the posterior aspect of the tibia, fibula, and the interosseous membrane. It courses posteriorly and medially around the ankle in a groove adjacent to the medial malleolus and inserts on the midfoot in the area of the navicular tuberosity.5,6
The medial malleolus serves to change the direction of pull on the tendon. [ and ] This is believed to increase the stresses on the tendon as rupture usually occurs in this area.5,7
The tibialis posterior functions as a plantar flexor of the ankle and an inverter of the subtalar joint complex.
Tibialis posterior tendon coursing posterior to the medial malleolus
The tibialis posterior muscle initiates the process of inversion of the hindfoot during gait bringing it into a neutral position. This muscle truly drives the position of the hind-foot and determines the flexibility of the foot by its control over the transverse tarsal joints. The loss of the inversion force of the muscle explains why patients with tibialis posterior tendon injuries have only a limited ability, or are completely unable, to rise onto their toes from a position of single-leg stance.6
While an acute tibialis posterior strain is uncommonly reported, the mechanism of the strain is relatively straightforward as a force imparted into the muscle exceeds its strength. On the other hand, the etiology of the more commonly investigated and reported tibialis posterior tendon dysfunction remains somewhat unclear and may include vascular, metabolic, or mechanical factors.8
Dysfunction of the tibialis posterior tendon is a common cause of acquired adult flatfoot deformity (AFFD).5
Middle age women are most commonly affected and the incidence is known to increase with age. Pes planus, hypertension, diabetes mellitus, and seronegative arthropathies have all been identified as risk factors for tibialis posterior dysfunction.9
Patients with tibialis posterior injuries will typically present with an insidious onset of vague pain in the medial foot and swelling behind the medial malleolus along the course of the tendon. Roughly half of all patients have a history of trauma that was initially thought to be a sprain.5,6
Symptoms are usually aggravated by standing and walking and in addition to pain patients often note dysfunction in their gait. Typically these patients are unable to run and note difficulty taking a long stride as well as they have an inability to push off onto their toes and raise their heel. Some authors describe patients with tibialis posterior dysfunction presenting simply with pain and apparent inflammation along the tendon without any evidence of clinical deformity but most patients have some collapse of the foot.6,9
Kohls-Gatzoulis et al. found that the complaint of medial pain or swelling behind the medial malleolus together with a change in foot shape identified 100% of patients with tibialis posterior dysfunction and had a specificity of 98%.9
Typically the physical examination of tibialis posterior dysfunction patients reveals a flatfoot deformity that consists of flattening of the medial longitudinal arch, hindfoot valgus, and abduction of the midfoot on the hindfoot. This abduction allows relatively more toes to be seen when standing behind the patient leading to the “too many toes” sign which is characterized by this condition.5,6,9,10
Patients typically have a flatfooted heel-toe progression and a poor or absent heel rise, in fact those with a dysfunctional tibialis posterior muscle asked to rise onto their toes from a position of single-leg stance are either completely unable to comply or can do so only to a limited degree.5,6,9
Ranges of motion are typically full in earlier stages of the condition and as the condition progresses the joints can lose motion and may eventually become fixed.5,9
Manual muscle testing of the tibialis posterior is performed by placing the foot in an everted, plantar flexed position and the patient is asked to invert the foot. Weakness or pain during contraction of an injured tibialis posterior muscle is characteristic. Palpation usually reveals tenderness along the distal aspect of the posterior tibial tendon from the medial malleolus to the navicular tuberosity; however, tenderness to palpation proximally along the musculotendinous junction of the tibialis posterior muscle may also be present in muscle strains. An accurate diagnosis of tibialis posterior tendon dysfunction can usually be made through a simple clinical examination however radiographic evaluation may be helpful in determining the severity of the condition or osseous involvement. Radiographic evaluation should include four weight-bearing films: an anteroposterior view of both ankles, an anteroposterior view of both feet, and lateral foot and ankle views of each side to allow comparison in patients who have unilateral disease. Typical deformity includes apparent shortening of the hindfoot on the weight-bearing anteroposterior radiograph, which is indicative of collapse through the subtalar joint complex. On the weight-bearing lateral radiographs, the inclination of the talus is plantarward in comparison to normal, with collapse typically through the talonavicular joint.6
A more overt muscle strain or tendonopathy would easily be visualized through a diagnostic ultrasound which would also be useful for grading the injury or quantifying any underlying inflammation.
Johnson and Strom11
initially described a classification scheme for tibialis posterior tendon insufficiency which was added to by Myerson.12
[See ] Although the classification is not predictive and does not consider the contracted gastrocnemius, the three stage scheme is useful for considering treatment strategies. In many ways, an acute tibialis posterior strain would be typical of stage 1 or stage 2 in this classification system.
It has been noted that there are difficulties with this classification systems reliability, making it somewhat difficult to compare results from various studies that use this system.
The tibialis posterior acts as a heel inverter creating an obliquity of the transverse tarsal joint, thereby allowing for a rigid midfoot during terminal stance, which in turn allows efficient transfer of stored energy in the lower extremity for toe-off and swing phase.6,13
Therefore, dysfunction of the tibialis posterior muscle results in less efficient gait, as the heel does not effectively medialize, and the gastrocsoleus complex requires greater excursion to become a heel inverter.13
Theoretically, rearfoot eversion and an increased medial longitudinal arch angle move the talonavicular and calcaneocuboid joints to a more parallel position, unlocking the foot for shock absorption. Gait patterns in normal subjects progress from a neutral (or slightly inverted position) to eversion at foot flat, the role of shock absorption is linked to these foot kinematics. While normal subjects increase rearfoot eversion and medial longitudinal arch angle throughout the stance, the subjects with posterior tibial tendon dysfunction are at, or near, peak rearfoot eversion and medial longitudinal arch angle during loading response. This failure of gradual shock absorption to occur may contribute to abnormal stresses on secondary ligamentous support (spring ligament, plantar fascia, interosseous talocalcaneal ligament) as the foot is loaded. During the terminal stance and pre-swing phases of gait, abnormal kinematics of the patients with posterior tibial tendon dysfunction suggests a failure to position the foot effectively for push off.14
Non-operative management of tibialis posterior injuries focuses on improving a patient’s symptoms, usually by attempting to decrease the forces which pass through the posteromedial hindfoot. Any acute inflammation surrounding the sheath of the tibialis posterior tendon should be dealt with before the chronic aspect of the condition is treated.9
Non-steroidal anti-inflammatory medication may decrease pain and associated swelling, however, the initial conservative treatment of acute injuries of the tibialis posterior dysfunction is not unlike any other muscle strain and should include P.R.I.C.E. principles: Protection, Relative Rest (allowing as much motion and activity as possible to counter the deleterious effects of disuse while not unnecessarily stressing the healing tissues), Ice, Compression, and Elevation. Conservative treatment for stage 1 and 2 tibialis posterior dysfunction is largely based on the clinician’s anecdotal evidence as the majority of the literature focuses on diagnosis, classification system, and operative options.
Alvarez et al. conducted a study involving non-operative treatment of stage 1 and 2 tibialis posterior tendon dysfunction which included prescription of orthotics and a rehabilitation program.15
The rehabilitation program focused on specific strengthening exercises for the tibialis posterior, peroneals, tibialis anterior, and gastrocsoleus. Progression was aimed at achieving high repetitions of double and single leg heel raises in order to train the muscles for long-term endurance. This study found that 89% of patients responded to a regimen of orthotic use and supervised physical therapy.15
The patient in our case study was treated with medical acupuncture (4 points surrounding the injury) with electrical stimulation (IC-1107+ at 2 Hz frequency), therapeutic ultrasound with Traumeel (5 minutes, 50% duty cycle, 1 MHz frequency, 0.7 W intensity), ART® of gastrocnemius, soleus, and tibialis posterior muscles above and below the injury, and Graston Technique© with GT 6 and GT 2 posterior to the medial malleolus followed by ten minutes of ice and elevation. The intent of these treatments was to restore the proper blood supply to the muscle, reduce fibrotic tissue/adhesions and restore function to the muscle.
, also referred to as an augmented soft tissue mobilization technique, employs specially designed stainless steel instruments with bevelled edges to augment a clinician’s ability to perform soft tissue mobilization. The instruments are utilized in a multidirectional stroking fashion applied to the skin at a 30°–60° angle at the treatment site. This application allows the clinician to detect irregularities in the soft tissue texture through the undulation of the gliding tools.16,17
In addition to removing scar tissue adhesions, Graston Technique®
is proposed to enhance the proliferation of extracellular matrix fibroblasts, improve ion transport and decrease cell matrix adhesions.16,17
Active Release Technique®
therapy is utilized with the underlying understanding that the anatomy of the limbs has traversing tissues situated at oblique angles to one another that are prone to reactive changes producing adhesions, fibrosis and local edema and resultant pain and tenderness.18,19
During Active Release Technique®
therapy, the clinician applies a combination of deep digital tension at the area of tenderness and the patient actively moves the tissue through the adhesion site from a shortened to a lengthened position.18,19
Activity modifications were also prescribed, including a break from his running training while continuing cycling and swimming with the use of a pullbuoy. Tibialis posterior strengthening exercises of heel-ups with a tennis ball between the medial malleoli were prescribed.14
A gait analysis and a gait scan was also performed from which orthotics were prescribed and fitted before running was resumed. The prescription of orthoses for early stage tibialis posterior dysfunction is well supported in the literature.5,6,9,14,15
A wide variety of operative treatments have been reported for tibialis posterior tendon dysfunction. Stage 1 and 2 dysfunction is rarely treated operatively unless conservative management has failed, at which time debridement and immobilization is considered. There are a variety of isolated soft-tissue procedures designed to compensate for a dysfunctional tibialis posterior tendon and these reconstructive surgeries or osteotomies are employed to improve alignment of the foot in stage 3 and 4 dysfunction. Recovery from reconstructive surgery is prolonged and an eventual return to asymptomatic unrestricted activities is unpredictable.5