Abstract
Background: The purpose of this study was to review the results of single and double-plate fixation combined with grafting with bone from the iliac crest performed by one surgeon as treatment for supracondylar nonunion of the femur.Methods: We performed a retrospective study of eighteen adult patients in whom a nonunion of the supracondylar region of the femur had been treated with single or double-plate fixation and autologous bone graft. The average time from the initial treatment of the fracture or the osteotomy to the index repair of the nonunion was fifteen months (range, five to thirty-six months), and nine patients had had a total of fifteen operations between the initial treatment and the repair of the nonunion. Two of these patients had had at least three procedures. Thirteen double plates, four single plates, and one interfragmentary screw were used for fixation of the nonunions, with onlay autologous bone graft used in all patients. The average time from the repair of the nonunion to the latest follow-up examination was twenty-six months (range, six to 120 months).Results: By the time of the latest follow-up examination, all eighteen nonunions had healed. One patient had needed repeat double-plate fixation and autologous bone-grafting to obtain union. Two patients had had the hardware removed because of pain or infection, one patient had had an implanted electrical bone stimulator removed, and one patient had had a quadricepsplasty to treat restricted motion of the knee. There were only three complications. These included one infection, which resolved with irrigation and débridement and the use of antibiotics; loss of motion of one knee; and one malunion. The average range of motion of the knee at the latest follow-up examination was 101 degrees (range, 10 to 135 degrees).Conclusions: Rigid plate fixation and autologous bone-grafting is an effective technique for the treatment of nonunions of the supracondylar region of the femur.
Nonunions of the supracondylar region of the femur, which are unusual, are most commonly due to a severe open fracture with extensive comminution and segmental bone loss. Another frequent cause is infection after internal fixation of a comminuted closed fracture. Such nonunions can also occur after treatment of osteoarthritis of the knee with supracondylar osteotomy. Published reports on the operative treatment of these difficult nonunions are limited.
The purpose of the present retrospective study was to review the results of single and double-plate fixation combined with grafting with bone from the iliac crest performed by the same surgeon as treatment for supracondylar nonunion of the femur. We present our operative technique, which emphasizes an anterior approach that permits exploration of the knee joint, preservation of the vascularity of the bone, and extensile exposure for rigid internal fixation and bone-grafting.
*One or more of the authors has received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.
†Department of Orthopaedic Surgery, University of California, Davis, 4860 Y Street, Suite 3800, Sacramento, California 95817.
We performed a retrospective review of the charts and radiographs of all patients who had been managed for supracondylar nonunion of the femur by one of us (M. W. C.), at the University of California, Davis Medical Center, between 1983 and 1997. A total of twenty-one patients who had nonunion either of a fracture or at the site of an osteotomy were identified. Two patients who had not been managed with plate fixation (one had intramedullary nailing, and one had bone transport) were excluded from the study. One additional patient was lost to follow-up; this patient had a postoperative wound infection that was treated with irrigation and débridement as well as intravenous administration of antibiotics for six weeks. At the time of the last follow-up examination, eighteen months postoperatively, the infection had resolved but the nonunion had not healed completely. The study group, therefore, consisted of eighteen patients (seven men and eleven women), fifteen of whom had nonunion of a fracture and three, nonunion at the site of an osteotomy (Table I). The average age of the patients at the time of the repair of the nonunion was forty-seven years (range, twenty-five to eighty-one years). Seven of the nonunions were on the left side, and eleven were on the right side. Six patients smoked more than one pack of cigarettes a day at the time of the repair.
Classification of the Original Fracture and Previous Treatment
The fifteen supracondylar fractures that led to the nonunions were classified with use of the system of the Orthopaedic Trauma Association9. Five of the fractures were type A, or extra-articular; seven were type C, indicating intra-articular extension; and three could not be classified because the original radiographs were not available. The fractures were also categorized as open (twelve fractures) or closed (three fractures). The open fractures were classified, according to the system of Gustilo et al.3,4, as type IIIA (ten), type IIIB (one), or type IIIC (one). The three supracondylar femoral osteotomies that were followed by nonunion had been performed to treat degenerative joint disease and malalignment.
Eleven of the fractures were treated initially with a fixed-angle device, with a condylar screw used for eight fractures and a blade-plate used for three. Three fractures were treated with a condylar buttress plate, and one, in a patient who was quadriplegic, with a pillow splint. A blade-plate had been used for fixation after one supracondylar femoral osteotomy; a dynamic compression plate, after another; and double dynamic compression plates, after the third.
A total of fifteen additional procedures had been performed in nine patients before repair of the nonunion (Table I). One patient had had five irrigation-and-débridement procedures as well as removal of the hardware and placement of an external fixator as treatment for a deep infection, one had had three irrigation-and-débridement procedures as well as removal of the hardware and placement of an external fixator as treatment for a deep infection, three had had removal of the hardware, and two had had autologous cancellous bone-grafting. Two patients had had a previous failed attempt at repair of the nonunion; one of these patients had had repeat plate fixation and bone-grafting and the other had had use of a supracondylar femoral nail.
Two patients had an active infection at the site of the nonunion: one with Staphylococcus epidermidis and Candida tropicalis and the other with Staphylococcus aureus at the time of presentation. As just described, these patients were managed with a staged protocol of irrigation and débridement of the infected site, removal of the hardware, placement of an external fixator, and intravenous administration of antibiotics for six weeks. Another patient had a remote history of infection but had no evidence of active infection at the time of presentation. At the time of the repair of the nonunion, no patient had any evidence of active infection and fifteen had no history of infection.
Classification of Nonunions
The diagnosis of nonunion was confirmed at the time of the operation by motion at the site of the fracture or osteotomy with no evidence of bone bridging the affected area. The preoperative diagnosis was based on clinical symptoms and physical findings, including pain at the site of the fracture or osteotomy that was aggravated by stress and the demonstration of motion at the site of the fracture. Radiographic criteria included the absence of bone bridging the site of the fracture or osteotomy and no evidence of progression of healing over a period of three months. We were unable to establish preoperatively, either clinically or radiographically, whether two patients had a painful malunion or a nonunion; the diagnosis of nonunion was confirmed by the operative findings.
The average duration of the nonunion, or the time from the initial treatment of the fracture or the osteotomy to the repair of the nonunion, was fifteen months (range, five to thirty-six months). The time from the initial fracture or osteotomy to the repair was at least five months in all patients.
The nonunions were classified on the basis of the presence or absence of callus, which indirectly reflected the vascularity of the nonunion. In three patients, the appearance of the nonunion could not be determined because the original radiographs had been destroyed. Five nonunion sites had no callus, nine had minimum or some callus, and one had abundant callus. One nonunion was classified as vascularized (vital) and seventeen were classified as avascular (nonvital), according to the system of Weber and Cech13. All of the nonunions were supracondylar, and the locations ranged from immediately juxta-articular to as much as nine centimeters proximal to the joint line.
Operative Technique
The patient is positioned supine on a radiolucent operating table after initiation of general or regional anesthesia. A c-arm fluoroscope is available. We do not use a tourniquet because it limits the ability to utilize extensile exposures. Seventeen of our patients had an operative scar; sixteen patients had had a previous straight lateral incision, and one had had a previous longitudinal medial incision. The eighteenth patient had been previously managed nonoperatively, as described. We prefer an anterolateral parapatellar longitudinal approach similar to that used for a total knee arthroplasty, as described by Henry6. Full exposure of the knee joint is afforded, and proximal extension of the incision allows visualization of as much of the femoral shaft as necessary to repair the nonunion. A skin incision was used when there was no risk of a skin slough between the sites of the new anterior approach and the previous lateral approach; this was possible in fourteen patients. We require a gap of at least seven centimeters between the incisions with good-quality intervening skin. Otherwise, the previous lateral incision is extended and undermined medially at the level of the fascia. The exposure through the muscles is then done, as described by Henry, to provide exposure of the nonunion. No patient needed a takedown of the quadriceps tendon from the patella, a z-plasty of the patellar ligament, or an osteotomy of the tibial tubercle.
For the anterior approach, a longitudinal midline skin incision is made. The interval between the rectus femoris and the vastus lateralis is identified proximal to the conjoined tendon of the rectus femoris and the vastus intermedius. The sheath of the rectus femoris is then incised sharply, and the muscle is isolated with blunt dissection from the underlying vastus intermedius distally as far as the conjoined tendon. The tendon is incised with an electrocautery knife along its lateral border into the suprapatellar pouch, with the dissection carried distally to the tibial tubercle in a lateral parapatellar fashion. If a posterior exposure of the lateral femoral condyle is needed, the incision is extended through the joint capsule parallel and just anterior to the muscle fibers of the vastus lateralis rather than parallel to the patellar ligament. Although this technique gives better lateral exposure, it limits the ability to reflect the patella medially. The rectus femoris is retracted medially, and the thinnest portion of the vastus intermedius is identified and is split longitudinally in line with the distal exposure as far proximally as needed to perform the procedure. The femur is exposed through subperiosteal dissection on its lateral and anterior surfaces, but care is taken not to expose or strip the posterior or medial surfaces. The patella and most of the quadriceps mechanism are retracted medially with narrow-tipped, broad-bladed retractors, such as narrow-tipped Hohmann retractors. Since these nonunions are close to the articular surface of the femur, it is usually necessary to detach the suprapatellar pouch from the femur. Care is taken to preserve the pouch so that it can be reconstructed when the wound is closed. If the pouch is scarred or obliterated, all of the scar tissue must be removed in order for motion to be restored.
Next, all of the hardware is removed and the site of the nonunion is exposed. If the fragments of the nonunion are in good alignment, with no more than 4 degrees of instability in any plane, they are stabilized with a plate and then an onlay cancellous bone graft is applied. In seventeen of our patients, there was malposition of the nonunion fragments with fibrous tissue filling the bone defect. In these patients, we completely mobilized the nonunion site and excised all fibrous tissue and nonviable bone. We then restored the alignment of the major fragments and achieved maximum apposition between the proximal and distal bone fragments. We accepted as much as two centimeters of shortening to obtain optimum apposition. As the primary goal of these procedures is healing of the nonunion and elimination of angular and rotational deformity, we believe that a limb-length discrepancy of as much as two centimeters should be accepted and should be addressed at a later date with a second procedure if necessary.
If the distal fragment is at least four to five centimeters long and the bone quality is adequate, a 95-degree titanium compression screw with a side-plate of the appropriate length is used. Fixation of at least eight cortices of the proximal fragment is obtained, preferably with four bicortical screws, while the site of the nonunion is compressed with a femoral distractor or clamps. Interfragmentary compression is achieved with a lag screw through the plate or, even better, with an independent screw placed in the anteroposterior plane independent of the plate. If the bone quality is poor and fixation with an interfragmentary screw cannot be secured, a second plate is added. This four, five, or six-hole large-fragment titanium plate (Alta System; Howmedica, Rutherford, New Jersey) is placed on the medial border of the anterior surface of the femur at an approximately 90-degree angle with the lateral plate (Figs. 1-A, 1-B, 1-C and 1-D). To avoid a stress-riser at the proximal end of the plates, the anteromedial plate is shorter and preferably smaller in its overall dimensions than the lateral plate. To avoid impingement of the patella on this plate at full extension, it may be necessary to notch the anteromedial surface of the femur just proximal to the articular surface so that the distal end of the plate can be inset. Preferably, the plate should be fixed with at least three bicortical screws both distally and proximally. The amount of bone available for fixation distally may be limited; however, rigid internal fixation must be achieved.
In the present series, two patients had insertion of two standard Alta broad plates; seven had double-plate fixation in which one of the plates was a fixed-angle device, most typically a condylar-type screw and side-plate; four had double-plate fixation in which one of the plates was a condylar buttress plate; two had insertion of a single condylar buttress plate (Figs. 2-A, 2-B, 2-C and 2-D); two had insertion of a single fixed-angle plate that consisted of an AO blade-plate and a condylar-type screw and side-plate; and one had insertion of a single interfragmentary screw to supplement a blade-plate that had replaced a preexisting blade-plate.
Corticocancellous bone is then obtained from the iliac crest, usually from the inner table superior to the acetabulum. If there is insufficient bone in the anterior crest, bone is obtained from the posterior superior iliac spine before the femur is exposed. For this procedure, the patient is placed initially in lateral decubitus or a prone position and is then rolled into a supine position for exposure of the nonunion. If a lateral approach to the femur is used, the patient can be placed in lateral decubitus, in which position both operative sites are available simultaneously. Defects in the supracondylar area of the femur that are normally occupied with trabecular bone are packed with autologous cancellous bone. Onlay corticocancellous strips are placed without cerclage wires along all major cortical defects. The grafts are held in place by the closure of the periosteum and the muscle envelope. Before all of the onlay grafts are placed, the cortex of the femur is petalled with a quarter-inch (0.64-centimeter) osteotome as far distally as possible, to a maximum of five centimeters, and proximally for five centimeters. This decortication is done between the plates and along the bone available posterolaterally and anteriorly where periosteal stripping has been done. Copious amounts of cancellous and, if necessary, corticocancellous bone are laid along the femur in these areas. Occasionally, insufficient bone surface is available for bone-grafting when just the anterior and lateral approaches are used. In these cases, the subperiosteal exposure is extended medially, but not posteriorly, so that the bone graft can be placed. We routinely take specimens of bone from the site of the nonunion for culture.
We do not use allograft to treat nonunions, and we do not customarily use bone-graft substitutes. In this series of patients, however, in addition to the autologous bone graft, a type-I collagen hydroxyapatite-tricalcium phosphate bone-graft substitute (Collagraft; Zimmer, Warsaw, Indiana) was used in one patient (Case 3) and interporous hydroxyapatite (Interpore International, Irvine, California) was used in another (Case 10). The patient who received Collagraft was randomized into a group being treated with this substance at a time when a randomized, prospective trial of the material was under way at our institution. The patient who received Interpore had massive loss of bone from the distal end of the femur and had already had bone obtained from both posterior iliac crests for the initial treatment of the open supracondylar fracture of the femur. The posterior half of the defect in this patient was bridged with autologous bone that had been obtained from both anterior iliac crests. The anterior half of the defect was filled with Interpore blocks. The nonunion in both of these patients healed uneventfully.
After the fixation and bone-grafting have been performed, the wound is irrigated thoroughly, with care being taken not to wash out the bone graft; suction drains are placed; and a meticulous layer-by-layer closure is performed. The periosteum and the vastus intermedius are closed as the first layer, and then the suprapatellar pouch is reconstructed and the synovial capsule and knee joint capsule are closed. The more superficial aspects of the joint capsule, the quadriceps expansion, and the interval between the vastus lateralis and the rectus femoris are then closed in a second layer.
The extremity is elevated in a bulky soft dressing and a knee immobilizer. On the first postoperative day, the patient is encouraged to get up to go to the bathroom and to move to a chair at bedside with use of a walker or crutches. Light touch of the foot to the floor is allowed for balance. The drains are removed when there is less than fifty milliliters of drainage in an eight-hour shift. Once the drains have been removed and the pain is well controlled, the patient begins rehabilitation of the quadriceps muscles with isometric contractions, which may be supplemented with electrical stimulation for muscle reeducation. Continuous passive motion is instituted as soon as the patient can tolerate it. The range of motion is increased quickly to the safest maximum range that will not put excessive stress on the operative construct as ascertained by examination of the knee at the time of the operation.
It is sometimes difficult to determine union on routine anteroposterior and lateral radiographs, as much of the site of the nonunion is obscured by the plates. We look for periosteal new-bone formation and incorporation of the bone graft along the periosteal surfaces of the femur at the site of the nonunion. This often necessitates that anteroposterior, lateral, and two oblique radiographs be made. Once early osseous union is evident, gradual progressive weight-bearing is allowed over a period of six to eight weeks until the patient is able to bear full weight without assistive devices. The patient must be monitored every three to six weeks during this time to be certain that the fixation remains solid.
Follow-up Evaluation
The patients returned for physical and radiographic examination at two to three, six, twelve, sixteen, and twenty to twenty-four weeks postoperatively. At each visit, the operative incisions, the range of motion, the length of the limbs, clinical signs of union such as painless weight-bearing and negative findings on varus-valgus and anteroposterior stress tests, and the use of any assistive devices were evaluated. The average duration of follow-up after repair of the nonunion was twenty-six months (range, six to 120 months).
The average time to union was eight months (range, three to twenty months); seventeen of the eighteen nonunions healed after one procedure. One patient needed additional plate fixation and autologous bone-grafting to obtain union. This patient had sustained an open (type-IIIA3,4), comminuted (type-C) supracondylar fracture of the femur, which had been treated initially with a 95-degree screw and side-plate and had failed to heal after twelve months. The nonunion was repaired with two plates, including another 95-degree screw and side-plate and a second straight plate, as well as autologous iliac crest bone graft. After sixteen months, there was no clinical or radiographic evidence of union so an additional operative procedure was performed with double straight plates, autologous iliac crest bone graft, and an implantable electrical stimulator (EBI Medical Systems, Parsippany, New Jersey). Union was finally achieved four months later. The patient returned to her preinjury level of activity, did not use any assistive devices, and had 0 to 120 degrees of motion of the knee at the time of the latest follow-up.
The average range of motion of the knee for the eighteen patients at the time of the latest follow-up examination was 101 degrees (range, 10 to 135 degrees). Only one patient lost substantial motion of the knee, with the range decreasing from 125 degrees of flexion preoperatively to 95 degrees of flexion at the latest follow-up examination. Seven patients had virtually no change in the range of motion postoperatively compared with preoperatively, and ten had 20 to 115 degrees of improvement in the total range of motion.
One patient had a 15-degree varus malunion after the proximal portion of the lateral plate pulled loose when he bore full weight early postoperatively against advice. The malunion was subsequently corrected with an Ilizarov procedure at an outside institution. No other patients had more than a 5-degree difference in varus, valgus, anteroposterior, or rotatory alignment compared with the normal, contralateral extremity.
One patient had two centimeters of shortening of the involved extremity postoperatively, and two patients had three centimeters of shortening. All three patients were managed satisfactorily with a heel-lift, and no additional procedures were necessary to treat the limb-length discrepancy.
At the latest follow-up examination, six patients still needed to use an assistive device: two patients used a wheelchair and one each used a cane, two crutches, one crutch, and a walker. Three of these patients used an assistive device because of painful posttraumatic arthritis; one patient used a device because of stiffness of the knee that did not improve after the repair; one patient, who was elderly, used a wheelchair only outside the home; and one patient, who was quadriplegic, used a wheelchair full-time.
Additional Procedures and Complications
Overall, seven additional procedures were performed in five patients. One patient had repeat plate fixation, bone-grafting, and implantation of an electrical bone stimulator, as described earlier. This same patient had the bone stimulator removed eleven months later after the nonunion had healed successfully. One patient had prominent and painful hardware removed. One patient had removal of the hardware followed by Ilizarov correction of a malunion several months later, as described earlier. One patient had a quadricepsplasty to treat stiffness of the knee.
One patient had an infection, and another had positive cultures but no infection. Osteomyelitis developed in the former patient after infection with Staphylococcus epidermidis. After the fracture united, the infection resolved following irrigation and débridement, removal of the hardware, and intravenous administration of antibiotics for six weeks. There had been no recurrence of the infection by the time of the latest follow-up examination at fifteen months. Staphylococcus epidermidis grew on intraoperative culture of specimens from the other patient, but there were no clinical manifestations of infection. The patient was managed with oral administration of rifampin and ciprofloxacin for three and a half months; there was no additional evidence of the infection by the time of the latest follow-up examination three years postoperatively.
As described, only one patient, an eighty-one-year-old woman, lost motion of the knee. Because of her age and frail health, the patient was unable to participate as hoped in the exercise regimen.
Nonunions of supracondylar fractures or after osteotomies of the femur seem to be rare, as we found only seven reports in the English-language literature1,2,7,8,11,12,14. These reports included a total of sixty patients who were managed with various methods (Table II); the largest series7,8 had sixteen patients. The rate of nonunion of supracondylar fractures of the femur has been estimated to range from 0 to 4 percent5. Little has been published on the treatment of supracondylar femoral nonunions. Altenberg and Shorkey1 reported on two nonunions and Scuderi and Ippolito11 reported on five nonunions that had been treated successfully with fixation with a blade-plate. Both series included only a few patients. In 1973, Solheim and Vaage12 reported less success with their nail-plate device; only two of three patients obtained union after one attempt at repair.
Moore et al.8 reported on a series of thirty patients who had complications after operative treatment of a supracondylar fracture of the femur. Sixteen patients had a nonunion. Ten had an aseptic pseudarthrosis, which was treated with a 95-degree blade-plate and iliac crest bone graft in seven patients and with electrical stimulation and a cast-brace in three. Six patients had a septic pseudarthrosis. This was treated with external fixation, irrigation and débridement, iliac crest bone graft, and antibiotics in two patients; with irrigation and débridement, bone-grafting, and parenteral administration of antibiotics, with the existing internal fixation in place, in two; and with an above-the-knee amputation in two. Union was achieved eventually in thirteen of the fourteen remaining patients. However, there were serious postoperative complications, such as residual axial malalignment in seven patients and a decreased range of motion of the knee, which was treated with quadricepsplasty, in six patients.
Recently, interest has focused on intramedullary nails. Beall et al.2 described the use of a transarticular intramedullary nail and bone graft to salvage eleven limbs with a difficult supracondylar nonunion; union was achieved in all but one patient. Although there was an initial loss of some motion of the knee, the preoperative range of motion was recovered after the nail was removed. In 1991, Wu and Shih14 reported union in five of their seven patients who had been managed with standard antegrade, interlocking femoral nailing. The two failures were due to broken implants. In 1995, Koval et al.7 reported that nine of sixteen nonunions that had been treated with retrograde GSH (genucephalic) nails did not heal and the hardware failed. Thus, the authors did not recommend this technique.
The literature supports the use of fixed-angle devices such as a blade-plate for the repair of nonunion of the supracondylar region of the femur. Although locking intramedullary nails have been used successfully for the treatment of acute fractures of the femur, including supracondylar fractures, the literature suggests that they may not be adequate for many of the nonunions encountered in this area. Wu and Shih14 commented that supplementary fixation was needed for some distal femoral nonunions because only one cross-locking screw could be inserted. Locking screws are inadequate for rigid fixation of nonunions in the supracondylar region of the femur because of its wide medullary canal, thin cortices, poor bone quality from disuse, and limited bone stock for screw purchase. Micromotion in the presence of internal fixation may predispose to nonunion10. The poor results reported after treatment of supracondylar femoral nonunions with intramedullary nails, except for those inserted with transarticular methods, suggest that rigid internal fixation may be necessary for the healing of such nonunions.
Our treatment of supracondylar nonunions of the femur emphasizes the preservation of the blood supply to the bone through exposure of only the anterolateral surface of the femur when possible, the achievement of maximum bone apposition between the main distal and proximal fragments with fixation that is sufficiently rigid to eliminate micromotion, the application of a copious amount of autologous cancellous bone graft, and the performance of soft-tissue procedures to restore as much motion of the knee as possible.
We prefer the anterior extensile exposure of the femur and knee described by Henry6 to the more commonly used lateral approach, as the anterior approach offers full exposure of the knee joint as well as ready access to both the anterior and the lateral surface of the femur. This permits complete débridement of the knee joint and any associated intra-articular scarring of the knee and the suprapatellar pouch as well as reconstruction of the suprapatellar pouch, which is essential for the restoration of motion of the knee. Although a formal quadricepsplasty is not a routine component of this operative approach, the wide exposure of the rectus femoris, the vastus lateralis, the lateral portion of the vastus medialis, and the vastus intermedius provides the opportunity for a modified quadricepsplasty, which is very helpful in restoring motion to the knee. The distal portion of the vastus intermedius is commonly found to be tightly attached to the anterior surface of the femur with scar tissue. The anterior extensile exposure permits release with resection of the dense scar tissue in the area that could limit flexion of the knee and could lead to reattachment of the muscle to the femur with scar tissue.
The success of the anterior extensile approach is evidenced by the fact that only one patient, an eighty-one-year-old woman, lost flexion (30 degrees) of the knee; seven patients retained the preoperative range of motion; and ten had substantial improvement in motion, with a maximum gain of 115 degrees. The other advantage of the anterior extensile approach is that the surgeon has a frontal view of the knee joint and femur with easy visualization of the lateral aspect as well. This is a major aid in the modification of the distal and proximal surfaces of the nonunion, which is necessary to restore alignment, to preserve bone stock, and to obtain a maximum surface area of apposition between the two bone fragments. Equally important, this approach permits the application of biplanar fixation, which is difficult through a lateral approach because of limited access to the medial side of the anterior surface of the femur.
We prefer a distal compression screw attached to a 95-degree side-plate for fixation because the rigidity of the construct resists varus deformity and it is much easier to apply than a fixed-angle blade-plate. Our second choice is a buttress plate with multiple 6.5-millimeter cancellous-bone and 5.0-millimeter cortical-bone screws through the distal end of the plate. This is particularly advantageous when there is inadequate bone stock or the quality of the bone is not sufficient to support the compression screw or when the nonunion is juxta-articular or intra-articular and multiple interfragmentary screws can be placed in a lag fashion to secure fixation, or both.
The disadvantage of a buttress plate with multiple screws is that it offers little resistance to varus deformity; therefore, the continuity of bone on the medial side must be reestablished or a second plate must be used. We found that the quality of cortical bone in the proximal fragment was always good and, therefore, four bicortical screws were sufficient for fixation. It has been our experience that residual motion at the site of the nonunion often leads to failure. Such motion is best detected by subjecting the site to a varus-valgus stress after the lateral fixation device, which we always apply first, is placed. If any motion is evident at the site of the nonunion, we use biplanar fixation. We prefer an anterior-to-posterior interfragmentary screw, as this requires the least exposure and causes the least devascularization of the bone. If these screws cannot be inserted, then we add a second plate on the anterior surface of the femur, as described in the operative technique. We were thus able to eliminate micromotion at the site of the nonunion in all of our patients.
Our bone-inductive and conductive material of choice for the treatment of nonunions is autologous cancellous bone from the iliac crest. When there are defects in the cortical shell, we use corticocancellous bone strips, which are laid in a barrel-stave fashion to close the defect, as described in the section on operative technique. It is important to emphasize that the quantity and quality of the iliac crest bone graft needed for supracondylar nonunions of the femur cannot be obtained through a routine procurement of the region of the anterior superior iliac spine. If an anterior graft is to be used, we prefer exposure of the inner table of the ilium in order to obtain corticocancellous bone strips down to the iliopectinate line as well as the copious cancellous bone that is available just proximal to the acetabulum. Even more bone graft can be obtained from the region of the posterior superior iliac spine; however, this procedure must be anticipated preoperatively in order for the patient to be positioned properly. We do not use allograft for the treatment of nonunions, as many of the nonunions referred to us have been treated previously with allografts and we have found little new-bone formation at the site of the fracture and a lack of incorporation of the allograft at the site of the nonunion at the time of our operation. Although a bone-graft substitute was used in addition to the autologous bone graft in two of our patients, these were both special circumstances, and we do not recommend the routine use of bone-graft substitutes for the treatment of nonunions.
A meticulous, secure, layered closure of the quadriceps mechanism and the knee joint capsule is essential for rehabilitation of the muscles and quadriceps mechanism. The layered closure minimizes the risk of adhesions between the components of the quadriceps mechanism and permits sliding of the muscles of the quadriceps on each other when early motion is initiated. Good cooperation on the part of the patient and a carefully supervised postoperative exercise program are essential for restoring and maintaining motion of the knee. Our patients begin isometric exercises and passive range-of-motion exercises of the knee with a continuous-passive-motion device as soon as the operative drain is removed, which is normally within twenty-four to forty-eight hours postoperatively. During this early phase of rehabilitation, it is important to have excellent pain control. Most patients have substantial pain when continuous passive motion is initiated, but the pain dissipates within a short period of time and patients tolerate the device quite well. Most patients can tolerate 0 to 40 degrees of motion immediately, and the range can be increased rapidly so that it is at least 0 to 60 degrees, and preferably 0 to 90 degrees, at the time of discharge from the hospital, normally four to five days postoperatively. Generally, we do not send the continuous-passive-motion device home with the patient, since they do not need it by that time and overuse of this device frequently results in a knee flexion contracture, as full extension is rarely achieved in the device. It is important for the patient to gain voluntary control of the quadriceps as soon as possible. This is facilitated by the use of electrical stimulation of the muscles for reeducation. On the operating table, nearly all patients have full extension and various degrees of flexion, depending on the preexisting condition. To avoid excessive stress on the implants, patients are permitted to exercise only to within 10 degrees of the full range of flexion noted after the fixation is completed and the knee is closed at the time of the operation. In most patients, this range is well beyond 90 degrees. Under the guidance of a physical therapist, active and active-assisted exercises are begun immediately. Progressive resistance exercises are added to the program after eight to twelve weeks as healing progresses, and passive range-of-motion exercises can be introduced by the therapist after full union is achieved. After the maximum benefit from supervised physical therapy is achieved, the patient is encouraged to continue the exercise program on his or her own on a regular basis for as long as one year after repair of the nonunion, as, in our experience, most patients gain additional motion between six and twelve months postoperatively.
Although twelve of our eighteen patients had a severe grade-III open fracture3,4 as the initial injury that led to the nonunion, only two had active infection at the time of presentation at our clinic and one had a history of infection that was inactive at the time of presentation. When there has been no clinical evidence of infection, we have not found it necessary to do an extensive workup for possible infection before operative treatment of supracondylar nonunions of the femur. In order to rule out infection, we took deep specimens of bone for culture from all patients who did not have a history of infection and we managed these patients with perioperative antibiotics, as is standard for a major orthopaedic procedure of this type. However, we did not take any other special precautions or measures for the treatment of infection. With use of this approach, only one patient had a clinical postoperative infection and one patient was managed with antibiotics because of positive cultures without clinical evidence of infection. Both of these patients had had a type-III open fracture. On the basis of these results, we concluded that an extensive workup for possible infection, other than the usual preoperative radiographs and blood analysis, is not necessary. However, deep bone specimens taken for culture at the time of the operation seem to be useful for identifying patients who may benefit from extended postoperative treatment with antibiotics.
We attribute the 100 percent rate of union of supracondylar nonunions of the femur in our series to excellent restoration of flexion of the knee, use of the anterior extensile approach described by Henry6, soft-tissue débridement and reconstruction, preservation of the blood supply to the bone, rigid internal fixation, use of copious autologous bone graft, and a vigorous rehabilitation program.
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