Posterior tibial tendon dysfunction (PTTD) can be a debilitating condition which affects up to 10% of the population (according to some reports; Kohls-Gatzoulis, 2004). If patients receive a diagnosis early enough there are plenty of treatment options available. However, it is not uncommon for the condition to be missed and not picked up by the appropriate health professional until years later, by which time there is also damage to the structures supporting the medial longitudinal arch. This paper examines the role of limb length discrepancy and explores whether this is another risk factor for the condition.
Association between leg length discrepancy and posterior tibial tendon dysfunction
Jose Antônio Veiga Sanhudo and Joao Luiz Ellera Gomes
Foot & Ankle Specialist (published online 12 February 2014)
Limb length discrepancies (LLD) have been associated with several different orthopaedic conditions because of the altered effects on gait and biomechanics. A literature search carried out by the authors found no studies investigating a correlation between PTTD and LLD. This case control study saut to find out whether LLD had a direct impact on the tibialis posterior tendon and concluded that “LLD may be a predisposing factor for the development of PTTD”
What it all means:
This study showed that the frequency of PTTD was similar in both longer and shorter limbs, despite the different biomechanical compensations. The study also showed that in the PTTD group, LLD was statistically more frequent and more severe than among controls (P < .001). This “suggests that even minor degrees of LLD may not be as harmless as some authors have maintained”. It should also be noted that the average BMI was higher in the PTTD group which could have influenced findings.
- The objective of this study was to compare the frequency and severity of LLD in a sample of patients with PTTD
- 118 patients with PTTD were compared with 118 symptom free subjects
- LLD was measured by conventional (radiographic) or computed tomography scanography
- Mean BMI was higher in the PTTD group (28.58 kg/m2) than the controls (24.87 kg/m2)
- Changes in gait biomechanics seen in patients with LLD were observed in both the shorter and longer limbs
- Statistical analysis showed significant differences in mean absolute and relative LLD values between the case and control groups.
- The authors recognise that there are multiple proposed risk factors which may also contribute to PTTD.
Putting it into practice:
- Limb length is difficult to accurately measure in clinic, however simple clinical tests can give the practitioner an indication as to whether there is a limb length discrepancy. In addition to traditional measuring from the medial malleoli to the anterior superior iliac spine (ASIS), try looking at the patient weightbearing and observe the position of anatomical markers such as knee creases, hip position, PSIS… etc…. Also, observe the dynamic leg length during the gait cycle. Build up an overall picture rather that relying on one test of measure.
- Remember that the exact risk factors for PTTD are still unclear. However, this study states that “60% of patients with the condition had one of the following clinical findings: hypertension, obesity, diabetes, history of trauma or surgery to the medial ankle or corticosteroid exposure”. The strongest correlation is thought to be obesity.
- Most authors have recommended orthoses to reduce excessive forces on the soft tissue structures when treating PTTD, however, there are no specific guidelines. Try prescribing Bio Unified prefabricated orthoses which are designed to increase 1st ray propulsion. This can help to reduce the time spent loading the posterior tibial tendon. Watch our webinar on PTTD.