and Mark T. Dahl2
Department of Orthopedic Surgery, University of California – Irvine, Orange, CA, USA
Limb Length and Deformity Correction Clinics, Gillette Children’s Specialty Healthcare and University of Minnesota, St. Paul / Minneapolis, MN, USA
KeywordsPeroneal nerve releaseParesthesiaCompartment syndromeStretchingSplintingNight positioning
The initial postoperative management for patients with self-lengthening intramedullary nails parallels that following trauma nail insertion . The surgical team manages the postoperative pain while being cognizant of the potential for evolving compartment syndrome or fat embolism syndrome.
Unlike most other surgical operations where the work is done when the patient leaves the operating room, a limb lengthening “procedure” takes months to complete. For this reason, success or failure depends upon postoperative management.
The principles of postoperative management described herein apply to any treatment protocol that slowly moves bone fragments, whether lengthening, correction of deformity, or bone transport for a skeletal defect. The suggestions for patient management apply to both intramedullary lengthening nails and external skeletal fixators.
Complications associated with the movement of bone fragments or the stretching of limbs have not been eliminated with Ilizarov’s methods of bone lengthening. To the contrary, surgeons, no longer bound to the need for bone grafting, now attempt to elongate limbs by up to 100% or more of the original length, a likely source of severe complications. Indeed, problems occur whenever elongation of a limb is attempted.
Postoperative Neurological Problems
Nerve or vessel stretching occurs infrequently with high-frequency/small-step elongation strategies. Nerves and vessels can tolerate up to 2 mm of distraction a day in many locations around the body.
The earliest manifestations of excessive nerve traction are paresthesia (tingling in the nerve distribution) followed by (or accompanied by) numbness. Stop the distraction immediately, and rest the limb for a day whenever a patient complains of tingling or numbness during limb lengthening. Usually, this solves the problem. Ilizarov, in fact, recommends stopping distraction 1 or 2 days for every 10 days of lengthening, in all cases. If the sensory abnormality does improve by stopping elongation, reverse the distraction back past the length where the altered sensation began. This should eliminate the problem.
If the tingling or numbness returns with resumption of distraction, something is wrong. With external fixation devices, a pin or wire is likely pressing against a neurovascular bundle. Usually, the patient will be able to identify the specific implant causing the problem. With intramedullary lengthening nails, nerve compression by a tight fascial band is the likely culprit. Typically, this occurs where the peroneal nerve crosses the fascia just beyond the neck of the fibula. Fascial release is, therefore, the best way to deal with the problem (Fig. 7.1).
Fascia release of the peroneal nerve near the fibular head. Both the overlying fascial band and the intramuscular septum where the nerve enters the anterior compartment should be released. Copyright 2016 NuVasive
Postoperative Vascular and Circulatory Problems
Hypertension or limb ischemia is unlikely to occur when a high-frequency distraction plan is followed.
Pulmonary emboli have occurred with patients subjected to all manners of limb reconstruction, including lengthening; however, the incidence is very low. Moreover, such cases may be related to inactivity, rather than a consequence of the procedure itself.
Compartment syndrome is always a risk when limbs are submitted to surgical manipulation, or any kind of trauma, for that matter. Undue pain is the hallmark of the condition, requiring prompt compartment release.
Typically, compartment syndrome will occur in tibial lengthening procedures, especially when marrow canal reamings extrude through the pre-osteotomy drill holes into the lateral compartment of the tibia. Some surgeons avoid drilling into this region of the limb during preliminary osteotomy site preparation, whereas others prophylactically release the compartment. The most important step of all , however, is postoperative vigilance.
Contractures, Subluxations , and Dislocations
Every limb lengthening operation can result in contracture, subluxation (incomplete dislocation), or even complete dislocation of an adjacent joint. This occurs because myofascial tissue resists elongation. It is generally believed that the fascial tissues surrounding muscle bundles, rather than the muscle cells themselves, are responsible for such problems. Hence, joint contractures during limb elongation tend to occur in the direction opposite the greatest muscle mass or thickest fascial structures.
During limb lengthening, myofascial tissues, by resisting elongation, create joint contractures, which limit the range of motion. This occurs either temporarily, or, if the problem is not addressed, permanently (Fig. 7.2). Furthermore, if left untreated during progressive limb lengthening, joint contractures worsen as elongation proceeds. The contracted joint gradually subluxes, whereby the articular surfaces of the joint are not perfectly congruent (subluxation means incomplete dislocation).
A not uncommon deformity after distal tibia and fibula lengthening: extension of the great toe and flexion of the lesser toes, caused by the arrangement of muscle origins near the osteotomy site. Copyright 2016 NuVasive
The last phase of this process occurs when the joint dislocates completely, a worrisome consequence of limb lengthening that can occur with either internal or external devices. Returning such a joint to its anatomic position typically involves extensive reconstructive surgery that includes shortening the elongated bone to its preoperative length, complex capsular reconstruction of the joint itself, and often angulation osteotomies adjacent to the joint. Moreover, such a joint is rarely, if ever, normal thereafter.
Ankle equinus and knee flexion contractures are the two most common types of deformities that occur with lower limb elongation. Likewise, hip flexion contractures can develop during femoral lengthening. These deformities should not be allowed to persist or worsen while the bone is being lengthened. If a knee flexion contracture is not corrected, progressive tightening of the hamstrings can lead to posterior subluxation of the knee (Fig. 7.3). If this subluxation is not recognized and corrected, a frank dislocation may occur.
Posterior subluxation of the knee. (a) Pre-op status after two previous femur lengthenings. (b) Gradual posterior subluxation of the knee during PRECICE® nail lengthening. (c) Further subluxation. (d) Rotation and subluxation. Nail reversed 10 mm; dynamic splint applied; 3-week intensive daily physical therapy. (e) Reduction without surgery, but 10 mm shorter than planned
In the hip, a dislocation is most likely to happen in a patient with femoral neck valgus or a shallow acetabular roof at the start of femoral lengthening.
It is possible for contractures , subluxations, or dislocations to occur at both ends of a bone simultaneously. Thus, a progressive knee flexion deformity during femur lengthening is often accompanied by a flexion contracture of the hip as well. As the hamstring muscles tighten, the patella and rectus femoris muscle are pulled distally by increased knee flexion. This combination causes the patient to stand with a flexed knee and hip, balancing the limb on his or her toes (Fig. 7.4).
A worrisome combination of joint contractures during femoral lengthening. Hamstring tightness causes knee flexion and posterior displacement of the tibia on the femoral condyles (“ski-slope knee”). This pulls the quadriceps distally, tightening the rectus femoris and resulting in hip flexion. If untreated, both the hip and knee can dislocate with further elongation of the bone. Copyright 2016 NuVasive
Important elements of every postoperative physical therapy treatment plan designed to prevent joint contractures, subluxation, and dislocations include muscle stretching, elastic and static splinting, appropriate nighttime positioning, and active use of the limb during the entire lengthening process.
As a rule, however, physiotherapy cannot prevent deformities that angulate a lengthening bone through the regenerate new bone; instead, the surgical strategy should include techniques to prevent deformation (with blocking screws, for instance) or ways with which to deal with the problem if it occurs.
Whenever bone fragments are moved with respect to one another, soft tissues are placed under tension; the greater the movement, the greater the tension. Therefore, physiotherapy strategies have been developed to maintain joint mobility during limb lengthening. Indeed, constant stretching of tightening tissues is the hallmark of proper postoperative management of a patient using any device that is lengthening bone and soft tissues.