Lower limb mal-alignment due to deformity is a significant cause of early degenerative change and dysfunction. Standard techniques are available to determine the centre of rotation of angulation (CORA) and extent of the majority of deformities, however distal femoral deformity is difficult to assess because of the difference between anatomic and mechanical axes. We found the described technique involving constructing a line perpendicular to a line from the tip of the greater trochanter to the centre of the femoral head inaccurate, particularly if the trochanter is abnormal. We devised a novel technique which accurately determines the CORA and extent of distal femoral deformity, allowing accurate correction.

Using standard leg alignment views of the normal femur, the distal femoral metaphysis and joint line are stylized as a block. A line bisecting the axis of the proximal femur is then extended distally to intersect the joint. The angle (Θ) between the joint and the proximal femoral axis and the position (p) where the extended proximal femoral axis intersects the joint line are calculated. These measurements can then be reproduced on the abnormal distal femur in order to calculate the CORA and extent of the deformity, permitting accurate correction.

We examined the utility and reproducibility of the new method using 100 normal femora. Θ = 81 ± sd 2.5. As expected, Θ correlated with femoral length (r=0.74). P (expressed as the percentage of the distance from the lateral edge of the joint block to the intersection) = 61% ± sd 8%. P was not correlated with Θ.

Intra-and inter-observer errors for these measurements are within acceptable limits and observations of 30-paired normal femora demonstrate similar values for Θ and p on the two sides.

We have found this technique to be universally applicable and reliable in a variety of distal femoral deformities.

Lower limb mal-alignment due to deformity is a significant cause of early degenerative change and limb dysfunction. Standard techniques are available to determine the centre of rotation of angulation (CORA) and extent of the majority of deformities, however distal femoral deformity is difficult to assess because of the difference between the anatomic and mechanical axes. We have found the described technique involving constructing a line perpendicular to a line from the tip of the greater trochanter to the centre of the femoral head inaccurate, particularly if the trochanter is abnormal. We have devised a novel technique which accurately determines the CORA and extent of distal femoral deformity, allowing accurate correction.

Using standard leg alignment views of the normal femur, the distal femoral metaphysis and joint line are stylised as a block. A line bisecting the axis of the proximal femur is then extended distally to intersect the joint. The angle (𝛉) between the joint and the proximal femoral axis and the position (p) where the extended proximal femoral axis intersects the joint line are calculated. These measurements can then be reproduced on the abnormal distal femur in order to calculate the CORA and extent of the deformity, permitting accurate correction.

We have examined the utility and reproducibility of the new method using one hundred normal femurs. Θ=81+/− sd 2.5°. As expected, 𝛉 correlated with femoral length (r=0.74). P (expressed as the percentage of the distal from the medial edge of the joint block to the intersection) = 61% +/− sd 8%. P was not correlated with 𝛉.

Intra-and inter-observer errors for these measurements are within acceptable limits and observations of twenty paired normal femora demonstrate similar values for 𝛉 and p on the two sides.

We have employed this technique in a variety of distal femoral deformities, including vitamin D resistant rickets, growth arrest, fibula hemimelia, post-traumatic deformity and Ellis-van Creveld syndrome. We find the system universally applicable and reliable.

Much has been written about the use of different treatment modalities in the management of distal femoral fractures. These articles, however, do not include the use of the Ilizarov frame amongst the modalities described. We have experience in the use of the Ilizarov frame in the definitive treatment of both non-union and acute fracture of the distal femur. We report our experience and conclusions.

The medical records of all patients who had undergone Ilizarov frame management for acute distal femoral fracture or established non-union were reviewed. Demographic data, the complications of surgery, duration of treatment with the frame and recorded outcome were noted. All patients were further assessed (either in clinic or by telephone interview) and completed a Short Musculoskeletal Function Assessment Form.

We have treated 17 patients (11 male, 6 female), 8 were acute compound fractures and 9 non union/infected ORIF’s of the distal femur. All patients have had their frames removed and were united. The mean age at the time of frame application was 36.6 years (range 18.7–58.7). The mean time from frame application to union was 230 days (range 81–514). Noted major complications included refracture in two patients, persisting infection in one, chronic regional pain syndrome in one and limited range of movement in all (mean knee movement of 62 ranging from 2–100). Two patients have had above knee amputations and a further patient has requested above knee amputation. Short Musculoskeletal Function Assessment Form shows significant dysfunction with a mean score of 42.9/100 (range 8.15–82.85).

Treatment of distal femoral fractures is notoriously difficult. Other treatment modalities (i.e. Intra Medullary (IM) supracondylar nail) offer many advantages over Ilizarov frame use.