Description
Although medial patellofemoral ligament (MPFL) reconstruction is recognized as the primary treatment for the unstable patella, in all cases, MPFL reconstruction should not be considered a stand-alone procedure. Patients with multifactorial patellar instability require surgical techniques that make sense for their predisposition. We have indicated a three-dimensional transfer procedure, medio-anterior-distal displacement of the tibial tuberosity (MADD). However, there are few reports on the clinical outcome of MADD procedures in such complex cases. This study evaluated radiographic, clinical, and functional short-term effects in patients with multifactorial patellar instability.
Methods
Eighteen patients, 20 cases (mean age at surgery, 23 years; range, 16-52 years) included in this study, who had multiple factors such as patella alta, trochlea dysplasia, and excessive tibial tubercle-trochlear groove (TT-TG) distance and underwent MADD procedure with minimum 1-year follow-up. We assessed the radiographic, clinical, and functional variables and complications.
Results
The mean follow-up period was 3.5 years. The mean Caton-Deschamps index changed from 1.4 (1.2-1.6) preoperatively to 1.0 (0.9-1.1) postoperatively (P <0.01). Trochlea dysplasia (Dejour classification) was type C: 15 cases and type D: 5 cases. The mean preoperative TT-TG distance was 20.3 mm (range, 15-25 mm). The apprehension tests became negative in all but one case, Dejour classification type D. The median Kujala score improved from 57.0 to 91.1(P< 0.01), and the median Tegner activity level enhanced from 2 to 4 (P <0.05). There were no cases of osteotomy nonunion and 2 cases (22.2%) with painful screws or transferred bone.
Conclusions
This study demonstrated that the MADD procedure could achieve patellar stability and radiographic, good short-term clinical and functional outcomes. The MADD procedure may be reasonable and safe as a treatment option for patients with multifactorial patellar instability. Further research is needed to increase the number of cases and to investigate long-term outcomes.
