At the time of the latest follow-up, the average knee score19 was 92 points (range, 77 to 100 points) for the affected limb and 96 points (range, 82 to 100 points) for the contralateral limb (Table II). Four patients (Cases 3, 4, 6, and 7) continued to engage in strenuous sports, including those involving running, jumping, and twisting, without any perceived limitations. In all four patients, the knee score was rated as excellent for both the affected and the unaffected extremity.
One patient (Case 5) had a varus osteotomy of the proximal part of the tibia at another institution at the age of sixteen years. At the time of the operation, she was a varsity-level basketball player and had pain in the lateral part of the knee during sports activities. Although the most recent radiographs that were available at the time of the osteotomy did not demonstrate any evidence of degenerative joint disease, an arthroscopic examination that was performed before the procedure revealed early degenerative changes in the articular surface of the lateral tibial plateau and the lateral meniscus. At the time of the operation, the metaphyseal-diaphyseal angle measured 10 degrees of valgus, the mechanical tibiofemoral angle measured 6 degrees of valgus, and the mechanical axis of the affected limb was twenty-one millimeters lateral to the center of the knee joint. The patient was able to return to varsity-level sports within ten months after the osteotomy but continued to have symptoms during strenuous athletic activities. At the time of the most recent follow-up, she was a full-time nursing student and continued to participate in recreational sports, at a lower level of performance. She noted occasional pain in the knee during light recreational sports as well as frequent pain and occasional swelling, stiffness, and giving-way during vigorous activities. The knee score was rated as fair on the affected side and excellent on the contralateral side.
Another patient (Case 2), a twenty-three-year-old man, reported occasional pain in the affected knee with light recreational sports as well as frequent pain and occasional swelling with vigorous activities. He noted frequent stiffness of the knee and mild grinding of the patella but no locking or giving-way. The knee score was rated as fair on the affected side and good on the contralateral side. Physical examination demonstrated a positive result on the McMurray test and lateral joint-line tenderness.
A third patient (Case 1), a twenty-six-year-old man, reported occasional pain in both knees with strenuous physical activity but continued to participate in recreational sports without any perceived limitations. The knee score was rated as excellent on both sides.
The ankle score15 averaged 92 points (range, 82 to 100 points) for the involved limb and 98 points (range, 92 to 100 points) for the contralateral limb (Table II). The ankle score on the affected side was rated as excellent for three patients (Cases 1, 4, and 6) and good for four (Cases 2, 3, 5, and 7); the score on the contralateral side was rated as excellent for all patients. Four patients (Cases 2, 3, 5, and 7) reported pain in the affected ankle. One patient (Case 2) reported mild, occasional pain that limited recreational activities, and he believed that he had an obvious gait abnormality. Three patients (Cases 3, 5, and 7) reported mild, occasional pain that did not limit recreational activities. Two of these patients (Cases 3 and 5) noted some difficulty with both ankles when negotiating uneven terrain, stairs, inclines, and ladders. The third patient (Case 7) reported that the affected ankle was occasionally unstable.
No patient reported any limitations in nonathletic activities due to problems related to the knee or the ankle. Only one patient (Case 2) stated that he was unhappy with the appearance of the affected limb because of its angulation and incisional scars (Figs. 5-A, 5-B, and 5-C).
Four patients (Cases 2, 4, 6, and 7) returned to the clinic for a physical examination at the time of the latest radiographic examination. None of these patients had evidence of weakness, instability, contracture, or joint effusion at the knee or the ankle. Tibial deformity was not clinically apparent in any of these patients. No patient reported the limb-length inequality to be a problem. No patient had an obvious gait abnormality, although formal assessment in our gait laboratory was not performed.
Valgus deformity after fracture of the proximal part of the tibia in children was first reported, in 1953, by Cozen7. Since that time, numerous reports describing this entity have appeared in the literature2-11,13,20,23,27,28,31,35-38. A review of four combined series of children who had a fracture of the proximal tibial metaphysis demonstrated that posttraumatic tibia valga occurred in fifty-four (53 percent) of 102 patients20,23,27,35.
A number of theories have been proposed to explain the development of valgus deformity following a fracture of the proximal part of the tibia, including medial gapping at the fracture site due to incomplete reduction or soft-tissue entrapment5,6,12,24,28,33,35,36, the restraining influence of the iliotibial band7, fibular tethering that restricts the growth of the lateral part of the proximal tibial physis30, stimulation and overgrowth of the medial part of the proximal tibial physis1,3,7,10,12,13,20,25,28,30,35-38, reduced blood supply to the lateral part of the proximal tibial physis20, an accelerated physiological response as the limbs shift from physiological genu varum to genu valgum14,20,26, and the effect of weight-bearing on an angulated tibia2. Several studies have shown that the maximum deformity occurs within approximately one year after the initial injury, long after the fracture has healed in satisfactory alignment3,7,10,20,23,28,33,37. This increasing deformity over time suggests a dynamic process. Osteomyelitis of the tibia3,31, tibial osteotomy31, and the removal of tibial bone for use as a graft13,31 also have been reported to cause a subsequent valgus deformity of the tibia.
In early studies of this entity2-11,13,20,23,28,31,35-38, there was little agreement with regard to how often or to what extent the deformity would spontaneously improve. Early operative intervention and a limited duration of follow-up of most of the patients in these series precluded an accurate description of the natural history of the deformity. In 1982, Skak28 attempted to outline the natural history of posttraumatic tibia valga by observing six children with this deformity for periods ranging from eighteen months to eleven years. Measurement of the metaphyseal-diaphyseal angle revealed that valgus angulation increased during the first year after the fracture, remained unchanged for one to two years, and then slowly improved. At the time of the latest follow-up, only one patient had a clinically noticeable deformity, and that patient had been followed for only eighteen months.
In 1986, one of us (L. E. Z.) and MacEwen37 reported on the seven patients who are described in the present study. The average duration of follow-up in the original study was thirty-nine months (range, twenty-eight to fifty-two months). Measurement of the metaphyseal-diaphyseal and mechanical tibiofemoral angles revealed that the valgus deformity increased during the period of fracture-healing as well as after union of the fracture. The angulation progressed most rapidly during the first year after the injury and then continued at a slower rate for as long as seventeen months, after which time spontaneous improvement was observed. Although the authors believed that adequate clinical correction occurred spontaneously in six of the seven patients, all of the children had some residual valgus angulation on the most recent radiographs.
Balthazar and Pappas3 reported on seven patients who had posttraumatic tibia valga, five of whom were managed with a corrective osteotomy and two of whom were managed nonoperatively. Valgus deformity recurred in all five of the patients who had an operation and resolved in both of the patients who were managed nonoperatively. Robert et al.23 reported on four patients who had an osteotomy for the treatment of posttraumatic tibia valga. Two patients had a compartment syndrome after the procedure, and two had recurrence of the deformity. Other authors have reported recurrence of the deformity after the achievement of satisfactory alignment with a corrective osteotomy4,5,9,11,13.
Our data suggest that the metaphyseal-diaphyseal and mechanical tibiofemoral angles improve spontaneously in every patient who has posttraumatic tibia valga. However, we had to modify the landmarks that were used to measure the metaphyseal-diaphyseal angle once the patients had reached skeletal maturity. Although every patient had a measurable decrease in valgus angulation in the affected limb over time, a decrease in valgus angulation (and even the development of varus angulation) also was observed in the unaffected extremity of five of the six patients for whom such data were available at the time of skeletal maturity. It could be speculated that this finding did not represent a true change in the metaphyseal-diaphyseal angle but rather was due to the alteration of the measurement system. The consistently larger decrease in the metaphyseal-diaphyseal angle on the affected side as compared with that on the unaffected side suggests that the finding is valid; however, the number of patients was too small for us to verify this statistically.
Some authors have suggested that proximal tibial remodeling accounts for most of the correction in patients who have posttraumatic tibia valga and that lesser degrees of distal tibial remodeling may produce an s-shaped tibia5,23,28,35,37. Our calculations of the proximal and distal remodeling angles confirm that, over time, most of the correction occurs at the proximal tibial physis although some distal remodeling does occur. However, we were unable to demonstrate a consistent pattern of varus correction at the level of the distal tibial physis.
Several studies have demonstrated a relationship between the magnitude of angulation or the level of a tibial fracture and the resultant increase in contact pressure in the ankle and knee joints, suggesting that the clinical course of malalignment is degenerative arthropathy17,22,29,34. In contrast, Merchant and Dietz18 evaluated thirty-seven patients at an average of twenty-nine years after a tibial fracture and concluded that the clinical and radiographic outcomes were unaffected by the magnitude of angulation or the level of the fracture. Tetsworth and Paley32 suggested that more than ten millimeters of deviation of the mechanical axis may predispose an individual to degenerative arthritis; however, they did not provide any clinical data to support this hypothesis.
In the present series, the mechanical axis of the affected limb was an average of fifteen millimeters lateral to the knee joint. Five patients (Cases 1 through 5) had more than ten millimeters of deviation of the mechanical axis, and two of them (Cases 2 and 5) became symptomatic. These same two patients had the greatest amount of deviation of the mechanical axis as well as the largest metaphyseal-diaphyseal and tibiofemoral angles at the time of the latest follow-up. One of them (Case 5) had pain in the lateral part of the knee that interfered with sports activities by the age of fifteen years. Although radiographs did not demonstrate any degenerative changes at that time, an arthroscopic examination revealed degenerative changes in the lateral compartment of the knee, and the patient subsequently was managed with a varus osteotomy of the tibia because of symptomatic malalignment. The other symptomatic patient (Case 2), a twenty-three-year-old man, had pain in the lateral part of the knee as well as effusion with physical activity. Although these symptoms may have been partially due to a lateral meniscal tear rather than to residual valgus alignment, it must be assumed that the patient has degenerative arthritis of the knee until it is proved otherwise.
To our knowledge, the present series of seven patients represents the longest follow-up study of posttraumatic tibia valga in the literature. We are not aware of any previous study that has delineated the natural history of this entity from the time of the initial injury through the time of skeletal maturity. Although two of our patients wore a brace at night for a short period of time early in the course of treatment, there is no evidence that this regimen altered the natural history in any way. The small number of patients and the variations in age, type of injury, and level of activity limited our ability to draw statistically valid conclusions. Although all seven patients had a radiographic examination and completed clinical questionnaires, three patients did not return for a physical examination.
In conclusion, the maximum deformity that is associated with posttraumatic tibia valga in children is reached approximately one year after the injury. The metaphyseal-diaphyseal and mechanical tibiofemoral angles improved spontaneously in every patient in our series and resulted in a clinically well aligned, asymptomatic limb in most. However, differences in the deviation of the mechanical axis were observed between the involved and contralateral limbs at the time of skeletal maturity. One patient had clear evidence of degenerative changes in the lateral compartment of the knee by the age of fifteen years, and another patient was thought to have such changes at the time of the latest follow-up. We recommend that patients with posttraumatic tibia valga be followed through skeletal maturity and that operative intervention be reserved for patients with symptoms.
*No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. No funds were received in support of this study.
Investigation performed at the Alfred I. duPont Institute, Wilmington
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