If proximal realignment procedures such as lateral release and medial reefing fail to correct the alignment of the patella, the surgeon may progress to a distal realignment procedure. A word of warning here - distal realignment is a specialist area. Be sure that your surgeon is experienced in this field.
There are a number of different procedures - some involve moving the tibial tubercle (the bony lump on the shinbone (tibia) a couple of inches below the kneecap - the bony point at which the kneecap tendon (patellar tendon) joins onto the tibia) and some involve pulling the kneecap itself by changing the forces through the patellar tendon.
The different procedures generally carry the names of the surgeons who first described and promoted them:
This procedure is mentioned here for completeness. This procedure is rarely performed, and only in those rare cases where the tibial tubercle is in a bad position and the patient dislocates or subluxes because of the tibia bone (or even the femur) being rotated.
In this procedure the bone is cut through and rotated, and fixed into a new position, in order to properly realign the tibial tubercle.
Maquet was the first to suggest that cutting the bone (tibial tubercle) to which the lower patellar (kneecap) tendon is attached, and bringing the kneecap forward would reduce the resultant backwards force described at the beginning of this page. He calculated that bringing the tibial tubercle forwards by two centimetres would reduce the backwards force by 50%. Some surgeons move it only one centimetre because they think that most of the effect comes in the first centimetre, and also the resultant deformity of the tubercle does not look so bad.
The Maquet operation requires a long cut alongside the kneecap and its tendon, and careful dissection of the kneecap tendon away from its underlying bone along its length. With a hammer and chisel the bone is cut, keeping the patellar tendon attachment intact and not breaking the bone piece free at the bottom end. The loosened piece of bone is then wedged forwards with a bone block, to elevate the tubercle by 1-2 cms. This bone block can be freeze-dried cadaveric (donor) bone, or can come from the patient's own hip (the top rim where you put your hands on your hips). Freeze dried is good as it does not compact as much as fresh bone.
Criticism of the Maquet is that the tubercle and tendon cannot easily be moved medially (towards the inner aspect of the knee) - maybe half a cm is possible, but not more. But there is no need for screws, and the patient is encouraged to mobilise early - CPM (continuous passive motion - on a CPM machine) and weight bearing (in an immobiliser) is begun immediately with weight bearing at 3-4 weeks post op.
This procedure is similar, but involves hinging the tibial tuberosity over medially.
The Fulkerson procedure differs a bit from the Maquet. Here the bone is actually 'splintered' ('greensticked') at the lower end, allowing for more medial displacement(the bit of bone and tendon are moved more towards the inner aspect of the knee) and screws are used to hold the bits in place.
This procedure is no longer done but is included here as there are many patients still symptomatic who have this procedure in the past. In a Hauser procedure, he tibial tubercle is moved medially but is not lifted forward (anteriorly). Due to the shape of the tibia, it the actually shifts posteriorly, and the patella may press down more strongly than before, causing pain.
In this procedure, the patellar tendon is split vertically. The outer (lateral) half is pulled through under the inner (medial) half and attached to the tibia, pulling the patella over to the medial side.