Chapter 34 Proximal and Distal Realignment
Surgical Overview
Proximal Realignment
• Proximal realignment is a soft tissue balancing procedure that involves the lateral retinaculum and/or the medial retinaculum or the distal portion of the vastus medialis.
• The medial patellofemoral ligament (MPFL), a discrete component of the medial retinaculum, provides the majority of passive medial restraint to lateral displacement of the patella, and the distal portion of the vastus medialis (commonly referred to as the vastus medialis oblique), through its insertion onto the medial side of the patella, is the major dynamic stabilizer of the patella.
• MPFL reconstructions utilize allograft or autograft tissue fixed at the adductor tubercle tensioned to balance the patella within the trochlea and fixed on the patellar side.
Distal Realignment
• Distal realignment is an osteotomy of the tibial tubercle, with subsequent transfer of the tibial tubercle, either medially, anteriorly, anteromedially, or distally.
• Fulkerson Anteromedialization Osteotomy is a combination of the uniplanar tibial tubercle transfer procedures, medialization (Elmslie-Trillat Osteotomy), and anteriorization (Maquet Osteotomy).
1 The tibial tubercle is osteotomized by angling a single straight cut in anteromedial to posterolateral direction, whereby both medialization and elevation can be obtained.
3 Complications with this procedure are related to fixation, fracture through the osteotomy or through the screw hole, wound healing, and possible deep venous thrombosis.
4 In cases with severe patella alta, the procedure is combined with distalization. Distal transfer of the tibial tuberosity allows the articular surface of the patella to engage in the trochlea earlier in knee flexion. The tibial tubercle osteotomy is performed, freeing it up circumferentially, and then transferred distally.
Rehabilitation Overview
• Avoidance of provoking signs and symptoms, such as joint effusion, active inflammation, and pain, should guide the rehabilitation process.
• In the early phases, attention must be paid to the healing process of the involved structures/soft tissues following proximal realignment and bony fixation following distal realignment.
• No healing constraints follow release of the lateral retinaculum; however, control of postoperative hemarthrosis is emphasized.
• Joint hemarthrosis is a concern with lateral retinacular release because of the proximity of the suprageniculate artery as it can lead to scarring and muscular inhibition. Bleeding in the joint will cause quadriceps inhibition, have a deleterious effect on joint proprioception, as well as the articular cartilage, and, ultimately, delay progression of rehabilitation.
• Quadriceps strengthening is an essential component of patellofemoral rehabilitation and must be performed in a pain-free arc of motion.
1 Knowledge of the location of the lesion as well as the patient’s subjective complaints will help determine this range.
• An understanding of the biomechanics of the patellofemoral joint is essential.
1 Articulation begins on the inferior patella with knee extension and moves proximally as the knee flexes.
• Another important consideration is the patellofemoral contact area. The contact load (force) divided by the contact area will determine the patellofemoral stress (stress=force/area).
• Quadriceps force and contact area vary according to knee flexion angles and thus has implications in prescribing quadriceps strengthening exercises. In closed chain activities, the stress increases from 0 to 90 degrees (force and contact area increase), whereas in open chain activities the stress increases as the knee extends (force increases as contact area decreases).
• The rehabilitation potential will be dependent on the indications for surgery (instability vs arthritis) and the chronicity of the condition, premorbid status, and prior surgical history.
• Exercise should be performed in an optimal loading zone, the level of activity that neither overloads nor underloads the affected tissues.
• Therapeutic exercise and activities of daily living (ADL) must be within the envelope of function, the safe range of painless loading compatible with tissue homeostasis.
• Rehabilitation must respect the healing process and the individual knee’s tolerance to imposed stresses. In short, at any given time each knee has an optimal window of function. If the knee is continually asked to work outside of this window, the window of function will become smaller. This philosophy underscores the importance of patient education. Understanding this concept will encourage compliance.
• The rehabilitation phases represent a continuum of rehabilitation rather than discrete, well-defined phases. Progression through the phases is dependent on the factors mentioned earlier, such as premorbid status and the chronicity of the condition.
Proximal Realignment Postoperative Phase I: Healing (Weeks 0 to 6)
GOALS
• Range of motion (ROM): 0-degree knee extension to 60-degree knee flexion (4 weeks); 90 degrees (6 weeks)
TREATMENT STRATEGIES
• Quadriceps reeducation (submaximal): biofeedback, electrical stimulation, quadriceps sets performed with a towel roll, multiangle open chain isometrics, closed chain quadriceps isometrics in sitting at 60-degree knee flexion
• Initiate proximal strengthening: straight leg raise (SLR) series; in supine, hip flexion can be performed with 20-degree knee flexion
