The management of osteoarthritis of the knee associated with patellar instability secondary to external tibial torsion > 45° is challenging. Patellofemoral biomechanics in these patients cannot be achieved by intra-articular correction using standard techniques of total knee replacement.

We reviewed seven patients (eight knees) with recurrent patellar dislocation and one with bilateral irreducible lateral dislocation who had undergone simultaneous total knee replacement and internal tibial derotational osteotomy. All had osteoarthritis and severe external tibial torsion. The mean follow-up was for 47.2 months (24 to 120).

The mean objective and functional Knee Society scores improved significantly (p = 0.0001) from 29.7 and 41.5 pre-operatively to 71.4 and 73.5 post-operatively, respectively. In all patients the osteotomies healed and patellar stability was restored.

Excessive external tibial torsion should be identified and corrected in patients with osteoarthritis and patellar instability. Simultaneous internal rotation osteotomy of the tibia and total knee replacement is a technically demanding but effective treatment for such patients.

We compared the incidence and severity of complications during and after closing- and opening-wedge high tibial osteotomy used for the treatment of varus arthritis of the knee, and identified the risk factors associated with the development of complications. In total, 104 patients underwent laterally based closing-wedge and 90 medial opening-wedge high tibial osteotomy between January 1993 and December 2006. The characteristics of each group were similar. All the patients were followed up for more than 12 months. We assessed the outcome using the Hospital for Special Surgery knee score, and recorded the complications. Age, gender, obesity (body mass index > 27.5 kg/m²), the type of osteotomy (closing versus opening) and the pre-operative mechanical axis were subjected to risk-factor analysis.

The mean Hospital for Special Surgery score in the closing and opening groups improved from 73.4 (54 to 86) to 91.8 (81 to 100) and from 73.8 (56 to 88) to 93 (84 to 100), respectively. The incidence of complications overall and of major complications in both groups was not significantly different (p = 0.20 overall complication, p = 0.29 major complication). Logistic regression analysis adjusting for obesity and the pre-operative mechanical axis showed that obesity remained a significant independent risk factor (odds ratio = 3.23) of a major complication after high tibial osteotomy.

Our results suggest that the opening-wedge high tibial osteotomy can be an alternative treatment option for young patients with medial compartment osteoarthritis and varus deformity.

We prospectively assessed the benefits of using either a range-of-movement technique or an anatomical landmark method to determine the rotational alignment of the tibial component during total knee replacement. We analysed the cut proximal tibia intraoperatively, determining anteroposterior axes by the range-of-movement technique and comparing them with the anatomical anteroposterior axis.

We found that the range-of-movement technique tended to leave the tibial component more internally rotated than when anatomical landmarks were used. In addition, it gave widely variable results (mean 7.5°; 2° to 17°), determined to some extent by which posterior reference point was used. Because of the wide variability and the possibilities for error, we consider that it is inappropriate to use the range-of-movement technique as the sole method of determining alignment of the tibial component during total knee replacement.