*4.2.3 Proximal realignment procedures*

The goal of proximal realignment surgery is to reestablish a dynamic balance of forces around the patella. In 1979, Insall and associates described the "tube" realignment procedure for the treatment of chondromalacia patellae [77]. The procedure consists of release of the medial and lateral retinacular tissue, which are sewn together over the quadriceps proximal to the patella. Since then, modifications of this procedure involving a lateral release, with a lateral and 1-cm distal advancement of the vastus medialis, have been described in the treatment of patellar dislocation.

### *4.2.4 Distal realignment procedures*

Historically numerous surgical procedures (such as Roux-Goldthwait procedure, Hauser procedure, Elmslie-Trillat procedure – to name a few) for restoring patellofemoral stability have been described. Few of these reconstructive techniques are still popular in some parts of the word. The Hauser technique has fallen out of favor because of high incidence of patellofemoral arthritis at long-term follow-up. The Elmslie-Trillat procedure allows medialization without posterior transfer of the tibial tuberosity in combination with lateral release and medial capsular reefing. Carney and associates [78] have reported the long-term outcome of the Roux-Elmslie-Trillat procedure for patellar instability. In their study, 18 patients who underwent the Roux-Elmslie-Trillat procedure for dislocation or subluxation of the patella were identified from a group previously evaluated at a mean follow-up of 3 years. The prevalence of recurrent subluxation or dislocation in patients with patellofemoral malalignment who underwent the Roux-Elmslie-Trillat procedure was similar (7%) at 3 and 26 years' of follow-up. Fifty-four percent of the patients rated their affected knee as good or excellent at 26 years' of follow-up. The long-term functional status of the affected knee in patients who underwent the Roux-Elmslie-Trillat procedure declined.

Anteromedial tibial tuberosity transfer has been described by Fulkerson [79, 80]. In this procedure, an osteotomy of variable obliquity is made. Such an osteotomy allows the degree of anterior and medial transfer of the tibial tuberosity that can be independently adjusted to address the patient's individual pathology. The Fulkerson procedure (anteromedial tibial tuberosity transfer) corrects the Q-angle with medialization of the tibial tuberosity and unloads the patellofemoral joint with anteriorization of the tibial tuberosity. A hinge of bone is maintained intact at the distal aspect of the tuberosity to facilitate healing. After the tibial tuberosity has been transferred anteriorly and medially, the bone pedicle is locked into position with two cortical screws. Molina and associates [81] have showed that the most predictable way of increasing contact area and decreasing patellofemoral stress is transfer of the tibial tuberosity 1 cm anteriorly and 0.5 to 1 cm medially.

The indications for anteromedial tibial tuberosity transfer are:


The contraindications for anteromedial tibial tuberosity transfer are:


The tibial tuberosity transfer procedure should not be performed in skeletally immature patients (who have open growth plates) with recurrent patellar instability due to the risk of premature closure of the physis and subsequent development of genu recurvatum.

#### *Patellofemoral Instability DOI: http://dx.doi.org/10.5772/intechopen.99562*

Complications of anteromedial tibial tuberosity transfer include skin slough, hematoma, wound infection, compartment syndrome, knee stiffness, persistent knee pain, delayed union or non-union at the osteotomy site, symptomatic hardware, hardware failure (loosening, migration or breakage of the hardware), risk of proximal tibial facture, and progressive chondral deterioration.

Fracture of the proximal part of the tibia or of the tibial tuberosity after anteromedial tibial tuberosity transfer has been reported by several authors [82–84]. In order to prevent the occurrence of such a complication, various preventive measures have been suggested; these strategies include avoidance of step cuts [82], an osteotomy of at least 5 cm in length and 0.75 cm in thickness to avoid fracture of the tibial tuberosity [82], protected weight-bearing for six to eight weeks in a hinged knee brace, and advancement to full weight-bearing only when the osteotomy site has fully healed radiographically [83–85].

Stetson et al. [83] reviewed the records of 234 patients who underwent anteromedialization of the tibial tubercle with oblique osteotomy. In their series, six patients (2.6%) had fractures of the proximal tibia postoperatively, within 13 weeks of the Fulkerson osteotomy. All fractures occurred after a change in the postoperative physical therapy regimen from partial weight-bearing to immediate full weight-bearing. Given this increase in fracture incidence, a more conservative postoperative physical therapy regimen was recommended. The authors concluded that patients should be non-weight-bearing initially, advanced gradually to partial weight-bearing, and allowed full weight-bearing only after the osteotomy site shows radiographic evidence of complete healing.

Cosgarea et al. [85], in their biomechanical study, performed oblique and flat osteotomies on 13 pairs of fresh-frozen cadaveric knees. The knees were then tested to failure on a materials testing system by exerting a load through the quadriceps tendon at a rate of 1000 N/sec to simulate a stumble injury. The authors found that the failure mechanism for flat osteotomies was more likely to be a tubercle "shingle" fracture, while oblique osteotomies more frequently failed through a tibial fracture or fixation failure in the posterior tibial cortex. These authors recommended flat osteotomy for patients with isolated recurrent patellar instability and an oblique osteotomy in patients who have concomitant patellofemoral pain or degenerative changes in the articular cartilage. In cases where an oblique osteotomy is used, the authors recommended postoperative brace protection and restricted weight-bearing until the osteotomy site heals.
