Small but Significant Effect on Patellar Height and Tibial Tuberosity-Trochlear Groove Distance Following Ascending Versus Descending Tibial Tubercle Osteotomy in Medial Open-Wedge High Tibial Osteotomy.

PURPOSE: To compare radiographic patellofemoral characteristics following ascending tibial tubercle (AT) and descending tibial tubercle (DT) medial open-wedge high tibial osteotomy (OWHTO).

METHODS

This retrospective single-center study included all patients who underwent AT-OWHTO or DT-OWHTO between October 2014 and December 2022 with complete radiographic datasets and ≥12 months of follow-up. Patellar height (Caton-Deschamps index) and tibial tuberosity-trochlear groove distance (TT-TG) were measured on standardized radiographs and computed tomography scans preoperatively and at 4.5 and 12 months postoperatively. Coronal alignment (hip-knee-ankle angle), sagittal alignment (posterior tibial slope), and hinge-fracture occurrence were analyzed.

RESULTS

A total of 106 knees from 103 patients (83 men, 20 women; mean age 43.5 ± 8.9 years) were analyzed (48 AT, 58 DT). AT-OWHTO decreased the Caton-Deschamps index from 0.79 ± 0.14 to 0.69 ± 0.13 (P < .001) and increased TT-TG from 12.71 ± 3.41 to 14.93 ± 4.01 mm (P < .001). DT-OWHTO maintained the Caton-Deschamps index (0.76 ± 0.13 to 0.75 ± 0.14; P = .054) and TT-TG (13.86 ± 4.65 to 13.37 ± 4.93 mm; P = .057). A total of 46 hinge fractures (43.4%) were detected, 19 in the AT-OWHTO and 27 in the DT-OWHTO group (P = .471).

CONCLUSIONS

A significant decrease in patella height and a significant increase in TT-TG were observed in AT-OWHTO, whereas these parameters remained stable in DT-OWHTO. Although the absolute magnitude of these radiographic changes was small, preoperative assessment of patellar height and TT-TG may assist in selecting the appropriate osteotomy technique to preserve patellofemoral joint alignment.

LEVEL OF EVIDENCE: Level III, retrospective cohort study.