Distal femoral condyle is more internally rotated to the patellar tendon at 90° of flexion in normal knees

Sharp margin of antero-inferior lateral femoral condyle as a risk factor for patellar tendon-lateral femoral condyle friction syndrome

OBJECTIVE

To determine the correlation between patellar tendon-lateral femoral condyle friction syndrome (PLFFS) and the morphological characteristics of the antero-inferior part of the lateral femoral condyle (ALFC) to explore the potential pathogenesis.

METHODS

A total of 170 knees of 140 patients with PLFFS (PLFFS group) were retrospectively analyzed using magnetic resonance imaging (MRI) data for a 4-year period from our database. The Insall-Salvati ratio, shape of the ALFC (SALFC, defined as two subtypes: sharp versus blunt), lateral femoral condyle angle (LFCA), lateral trochlear length (LTL), and lateral trochlear height (LTH) were measured on MRI. Two groups were enrolled as controls: pure patella alta group (n = 192) and normal group (n = 172). All the parameters of the PLFFS group were compared with those of the two control groups.

RESULTS

The LFCA was significantly lower (p < 0.001) in the PLFFS group than in the pure patella alta group. The SALFC was significantly different (p < 0.001) in these two groups, whereas the Insall-Salvati ratio, LTH, and LTL showed no significant difference. The LFCA, LTH, SALFC, and the Insall-Salvati ratio in the PLFFS group were also significantly different (p < 0.001) with the normal group. Receiver operating characteristic (ROC) analysis showed the efficacy of the Insall-Salvati ratio and SALFC was better than that of the other parameters.

CONCLUSIONS

The morphological characteristics of ALFC are correlated with PLFFS. The sharp shape of ALFC may be an important causative co-factor along with patella alta in the pathogenesis of PLFFS.

KEY POINTS

• A sharp margin of the antero-inferior lateral femoral condyle is an important risk factor for the development of PLFFS in patients with patella alta. • Antero-inferior femoral condyle shape can easily be assessed with high intra- and inter-reader reliability PLFFS. • PLFFS is more common in young adults.

Surgical Treatment for Failure of Repair of Patellar and Quadriceps Tendon Rupture With Ipsilateral Hamstring Tendon Graft

Tears of the patellar and quadriceps tendon are common in the active population, especially in athletes. At present, several techniques for surgical repair and reconstruction are available. When reruptures occur, a reconstruction is mandatory. In the present paper, we describe a surgical technique for patellar and quadriceps tendon reconstruction using ipsilateral hamstring autograft. After routine hamstring tendon harvesting, the tendon ends are prepared using a whip stitch. A transverse tunnel is drilled in the midportion of the patella, the hamstring graft is passed through the patella, and firmly secured to the patellar tunnel openings with sutures. The details of the technique are fully described. Autologous ipsilateral hamstring tendon grafts provide a secure sound means to manage these challenging injuries.

Neutral mechanical alignment: Is it Necessary?

The cause of dissatisfaction following total knee arthroplasty (TKA) remains elusive. Much attention has been focused on static mechanical alignment as a basis for surgical success and optimising outcomes. More recently, research on both normal and osteoarthritic knees, as well as kinematically aligned TKAs, has suggested that other specific and dynamic factors may be more important than a generic target of 0 ± 3º of a neutral axis. Consideration of these other variables is necessary to understand ideal targets and move beyond generic results.