Abstract
Objectives:
Patients with trochlear dysplasia often undergo primary procedures other than a trochleoplasty for recurrent patellar instability. When these other procedures fail and a trochleoplasty is performed, it is unknown if these patients do as well as those that had a trochleoplasty as their primary operation. The purpose of this study was to compare the clinical outcomes after trochleoplasty for severe trochlear dysplasia between a group of patients who previously underwent surgery for patellar instability to a group who underwent trochleoplasty as their initial procedure.
Methods:
In this prospective cohort study with IRB approval, 40 patients who underwent a sulcus-deepening trochleoplasty as well as additional related procedures with at least one year follow-up were divided into two cohorts: 1) patients with prior surgery for patellar instability (n=19) [Table 1] and 2) patients with no prior surgery for patellar instability (n=21). Preoperative and postoperative IKDC and Kujala scores, in addition to patient satisfaction scores, recurrent dislocation events, and reoperations were compared between the two cohorts.
Results:
33 females and 7 males with an overall average age of 20.4 years with an average follow-up of 2 years were included in the study. Compared to preoperative scores, significant increases were seen in the postoperative IKDC and Kujala scores in both the primary (26.9 +/- 24.3, 21.5 +/- 22.3, respectively) and revision cohorts (22.7 +/- 23.0, 12.7 +/- 15.7, respectively) [Table 2]. There were no significant differences between outcome scores between cohorts with regard to final scores (p=0.661, 0.810, respectively) or absolute improvement (p=0.624, 0.284, respectively). There were no episodes of recurrent instability in either cohort. 23.8% of the primary cohort and 26.3% of the revision cohort underwent a secondary procedure for arthrofibrosis (p=0.420). There was no significant difference in satisfaction scores between the two cohorts, with an average score of 9.2 +/- 1.8 amongst all patients (p=.404).
Conclusion:
Patients with severe trochlear dysplasia will experience significant improvement postoperatively and will have equivalent outcomes if a trochleoplasty is performed as an index procedure or as a revision procedure following a prior failed patellar stabilizing procedure.
List of procedures that the revision cohort Underwent prior to the trochleoplasty. Note: Twelve patients underwent more than 1 prior patellar stabilizing procedure so the number of patients add up to more than the cohart size of 19.
| Prior Procedure | Number of Patients |
|---|---|
| Anteromedialization Tibial Tubercle Osteotomy | 7 |
| Medial Patellofemoral Ligament Reconstruction | 7 |
| Medial Patellofemoral Ligament Imbrication | 7 |
| Lateral Release | 9 |
| Patellofemoral Shaving Chondroplasty | 6 |
| Removal of Knee Loose Bodies | 6 |
Comparison of preoperative patient characteristics between the two cohorts.
| Preoperative Characteristic | Primary Cohort | Revision Cohort | p value |
|---|---|---|---|
| Total Number of Patients | 21 | 19 | - |
| Female Gender | 17 | 16 | 0.787 |
| Age (years) | 17.4±3.7 | 23.6±7.6 | 0.002 |
| Duration of Instability (months) | 56.8±54.3 | 102.8±91.7 | 0.058 |
| Type B Trochlea | 18 | 16 | 0.894 |
| Tobacco Use | 0 | 0 | 1.000 |
| Diabetes Mellitus | 1 | 0 | 0.335 |
| Body Mass Index (kg/m2) | 29±7.0 | 26.0±5.4 | 0.115 |