Statistical Analysis
Paired t tests were used to determine if significant changes occurred as a consequence of the surgery for the outcome variables (P < .05). Normative gait data were used to assess the quality of any changes that occurred in the variables, but no statistical analysis was performed to determine significant differences.18
Results
All 11 patients had clinical and radiographic evidence of healing and deformity correction at most recent follow-up. Nine patients (82%) healed after the index procedure. Mean total angular correction in the coronal plane was 21° (range, 14° varus to 7° valgus), and mean total angular correction in the sagittal plane was 9° (range, 21° recurvatum to 15° procurvatum) (Table 2).
For the group, mean preoperative MFA score was 39 (SD, 18; range, 10-69), and mean postoperative MFA score was 28 (SD, 14; range, 8-53). Patients reported the most improvement in 2 domains: In Leisure, mean (SD) preoperative score was 8 (2), and mean postoperative score was 5 (2); in Emotional, mean preoperative score was 5 (2), and mean postoperative score was 4 (1). The other domains were not significantly different between the 2 assessments.
On the SF-36, mean (SD) PCS significantly (P < .05) improved from 32 (8) to 43 (9). Mean (SD) MCS showed little change: preoperative, 46 (16); postoperative, 48 (13). The PCS subcategories that showed the most improvement were Physical Function, mean (SD) preoperative, 26 (20), to postoperative, 52 (26); Role of Physical Health, preoperative, 18 (24), to postoperative, 60 (41); and Bodily Pain, preoperative, 39 (27), to 58 (18).
The results from the preoperative and postoperative gait analysis showed no significant differences for the ankle, knee, and hip variables during swing phase (Table 3). In an analysis of the changes in joint kinematics during stance, maximum hip adduction (increased) and maximum knee varus (decreased) on the operative side were significantly improved toward normative values as a consequence of the surgery (Table 3). The other kinematic stance variables were not significantly different. No significant changes were observed in stance time, step length, stride length, cadence, or speed as a consequence of the surgery (Table 4).
Discussion
Correction of malaligned tibias leads to improved limb alignment and patients’ perceptions of functional abilities and health but had a limited effect on joint kinematics and gait. In a group of like patients, we used common techniques to realign malunited tibias and validated instruments to measure functional outcome, health status, joint kinematics, and gait. The goals of this study were to evaluate changes in perceived function and health status and changes in joint kinematics and gait as a result of correction of a posttraumatic limb deformity.
Other investigators have reported outcomes of treating symptomatic malunions,32 nonunions,24 and leg-length discrepancies.33 In these reports, correction of deformity improved patient satisfaction and function, though objective means of assessment were infrequently used. Good results were reported with use of a dome-shaped supramalleolar osteotomy for the correction of tibial malunion.32 In this study, supramalleolar osteotomy was performed on 8 patients for correction of a malunited tibia. Postoperative assessment included subjective assessment of pain, limp, appearance, instability, and activity. Of these 8 patients, 7 reported overall symptomatic improvement after healing, and the 1 who lost the deformity correction remained symptomatic. Significant improvement in overall health has been reported after successful treatment of tibia nonunions.24 The investigators used the SF-36 to assess patients who underwent treatment for a tibial nonunion. Analysis of these patients’ results showed a significant improvement in physical and mental functioning after healing. In addition, improved gait symmetry was reported in patients successfully treated for leg-length discrepancies.33 Unfortunately, how improvement in gait related to overall patient function was not assessed. In the present study, we used stringent objective and subjective validated instruments to assess changes in joint gait kinematics and functional outcome before and after treatment of a tibial malunion. In general, our results are consistent with published results and indicate that realignment of tibial malunions improves patients’ perceptions of function. Our results also indicate improvements toward normative values in maximal hip adduction and knee varus, thus confirming the efficacy of the surgery from a functional perspective. Unfortunately, we did not show significant improvements in the remaining joint kinematics measurements or temporal gait parameters.
It is not entirely clear whether tibial malalignment leads to degenerative changes of the ipsilateral knee and/or ankle and what role this might play in functioning. In a retrospective analysis of 92 patients, angular deformity within 15° of normal alignment did not lead to ankle arthrosis.9 Milner and colleagues4 found that, though varus malunion of the tibia may lead to arthrosis of the medial compartment of the knee, other factors were more important in causing arthrosis of the ankle.