A modified tibial tubercle osteotomy for patellar maltracking

Abstract

An abnormal lateral position of the tibial tuberosity causes distal malalignment of the extensor mechanism of the knee and can lead to lateral tracking of the patella causing anterior knee pain or objective patellar instability, characterised by recurrent dislocation. Computer tomography is used for a precise pre-operative assessment of the tibial tubercle-trochlear groove distance. A distance of more than 15 mm is considered to be pathological and an indication for surgery in symptomatic patients. In a prospective study we performed a subtle transfer of the tibial tuberosity according to the information gained from the pre-operative CT scan. This method was applied to two groups of patients, those with painful lateral tracking of the patella, and those with objective patellar instability. We evaluated the clinical results in 30 patients in each group. The outcome was documented at 3, 12 and 24 months using the Lysholm scale, the Kujala score, and a visual analogue pain score. Post-operatively, all but one patient in the instability group who had a patellar dislocation requiring further surgery reported good improvement with no further subluxation or dislocation. All patients in both groups had a marked improvement in pain and functional score. Two patients sustained a tibial fracture six and seven weeks after surgery. One patient suffered a per-operative fracture of the tibial tubercle which later required further fixation. If carefully performed, this type of transfer of the tibial tubercle appears to be a satisfactory technique for the treatment of patients with an increased tibial tubercle-trochlear groove distance and who present with symptoms related to lateral maltracking of the patella.

Does Landmark Selection Affect the Reliability of Tibial Tubercle-Trochlear Groove Measurements Using MRI?

“…One deficiency is in defining which landmarks should be chosen to measure lateral offset. The tibial tubercle and the osseous trochlear groove are uniform landmarks in numerous studies using CT [7,12,13,16,29], but better observation of soft tissues has led to variability in landmark selection in studies using MR images [2,3,14,20,30]. One study [20] compared MR and CT images for measurement of lateral offset using traditional osseous landmarks and a more functional soft tissue landmark (the distance from the center of the patellar tendon to the trochlear groove [PT-TG]), concluding that there was no difference and that they could be used interchangeably.…”

Patellar instability

“…Group 1 consisted of 30 patients with patellar instability and group 2 included 30 patients with painful lateral tracking of the patella, defined on CT and physical examination. After tibial tubercle transfer, 97% of patients had no subsequent episodes of patellar instability and both groups had significant and similar improvements in pain and function 51 . Nakagawa et al performed tibial tubercle medialisation in 39 patients with recurrent patellar instability.…”

Modified Technique of Tibial Tuberosity Transfer

“…11 Tibial tuberosity transfer, although a straightforward procedure, can result in major complications such as proximal tibial fractures. 9,10 Koeter et al 9 reported that 29 of the 60 patients (48%) in their series needed removal With the foot internally rotated, osteotomy is performed using an oscillating saw, and at the distal end, the saw blade is angled upward to exit the anterior cortex. MODIFIED TIBIAL TUBEROSITY TRANSFER e351 of screws because of symptoms from prominent screws.…”

“…8 Tibial tuberosity transfer, though considered a straightforward procedure, can lead to major and minor complications. 9,10 Our technique incorporates subtle modifications in terms of the way tibial tubercle osteotomy is performed and use of cannulated screws for fixing the osteotomy, thus minimizing the risk of complications (Tables 1 and 2). …”