Giant cell tumour of tendon sheath is a benign soft tissue lesion most commonly found in the flexor aspect of hand and wrist. However, it is uncommon in foot and ankle and rare in bilateral achilles tendon. We report a case of 17-year-old female who presented with progressive enlargement of bilateral achilles tendon for six months. MRI findings showed that most of the tumour had intermediate to low signal intensity. Histopathology confirmed the diagnosis of giant cell tumour of tendon sheath. To help the patient regain the strength of the achilles tendon and walking abilities, a large area of tendon tumour was excised, followed by reconstruction with transfer of the peroneus brevis (PB) and posterior tibial (PT) tendon autograft. At two years followup, functional result was satisfactory.

Introduction: An increased tibial tuberosity-trochlear groove (TTTG) distance is used for deciding a treatment plan in patello-femoral instability (PFI). The centre of the patellar tendon and the chondral trochlear groove can be directly visualised on MRI, and measured, giving the patellar tendontrochlear groove (PTTG) distance. A study was designed to compare the inter-rater and the test-retest reliabilities of PTTG and TTTG measurements in MRI of patients without PFI and in a group with PFI. Materials and Methods:This cross-sectional reliability study was done on archival MRI films of 50 patients without patellar instability and 20 patients with patellar instability. TTTG and PTTG distances were independently measured by two orthopaedic surgeons and two radiologists. A hybrid PTTG measurement with bony landmarks on the femoral side and the patellar tendon landmark on the tibial side, was used to estimate the influence of the differences in the femoral and tibial landmarks on the difference in reliabilities. The intra-class correlation coefficient (ICC) was calculated for all four raters, as well as separately for each rater. Results: The PTTG distance had a higher inter-rater reliability (ICC=0.86, 95% CI=0.79-0.92) compared to the TTTG distance (ICC=0.70, 95% CI=0.59-0.80) in patients without PFI. Similar trends were seen in patients with PFI (0.83 vs 0.66). The inter-rater reliability for the hybrid PTTG distance was found to lie in between the TTTG and PTTG. Conclusions:The MRI-based PTTG distance had better inter-rater reliability compared with the MRI-based TTTG distance.