Incidence and risk factors for lateral hinge fractures in medial opening wedge high tibial osteotomy and medial opening wedge distal tibial tuberosity osteotomy

Clinical Outcome of Combined Types 1, 2, and 3 Lateral Hinge Fractures After Open-Wedge High Tibial Osteotomy: A Case Report

Lateral hinge fractures (LHFs) after open-wedge high tibial osteotomy (OWHTO) pose the risk of delayed bone union and loss of correction, and their management remains a challenge. The following case report describes a rare case of combined type 1, 2, and 3 LHFs following OWHTO. The patient was a 48-year-old female with a history of desmoid tumor resection and radiotherapy on the ipsilateral posterior aspect of the thigh, which was distal to the popliteal area of the knee. Bone atrophy was observed in the proximal tibia. OWHTO was performed for medial knee osteoarthritis (Kellgren-Lawrence grade 3) with a correction angle of 13°. Two months after surgery, types 1, 2, and 3 LHFs were identified. Treatment included weight-bearing restriction and low-intensity pulsed ultrasound (LIPUS), which resulted in successful bone healing. During the 16-month follow-up, the patient was pain-free and could walk smoothly. This case was complicated by types 1, 2, and 3 LHFs after OWHTO because of factors such as large preoperative hip-knee-ankle angle, proximal tibia bone atrophy, insufficient screw length, and the distance between the plate and bone. The combination of weight-bearing restriction and LIPUS effectively managed multiple LHFs after OWHTO, preventing significant correction loss and nonunion by promoting bone healing.

Postoperative onset lateral hinge fracture is a risk factor for delayed union of the tibial tuberosity in medial opening wedge distal tibial tuberosity osteotomy

Background

This study aimed to evaluate bone union of the tibial tuberosity in patients undergoing medial opening wedge distal tibial tuberosity osteotomy (OWDTO). It was hypothesized that bone union of the tibial tuberosity could be associated with lateral hinge fractures (LHFs), but not thickness of the tibial tuberosity osteotomy.

Methods

Data of 61 consecutive patients who underwent OWDTO were retrospectively reviewed. Radiographic parameters of the lower limb and LHFs were evaluated. Thickness of the tibial tuberosity osteotomy and bone union of the tibial tuberosity were assessed at 1, 2, 3, 4, and 5 cm distal to the most proximal part of the tibial tuberosity on computed tomography. Bone union was assessed. Factors related to bone union of the tibial tuberosity were analyzed.

Results

There were 13 postoperative onset LHFs: all healed with conservative treatments within 6 months after surgery. The total score of bone union of the tibial tuberosity was 8.4 ± 2.1 points, which correlated with age, postoperative medial proximal tibial angle (MPTA), correction angle, and postoperative onset LHF (r = 0.307, 0.388, 0.275, and -0.624, respectively; p = 0.016, 0.002, 0.033, and <0.001, respectively). Regression coefficient for postoperative onset LHF, postoperative MPTA, and body mass index were -0.619 (p < 0.001), 0.285 (p = 0.003), and -0.227 (p = 0.021), respectively.

Conclusion

Postoperative onset LHFs, but not thickness of the tibial tuberosity osteotomy, were a risk factor for delayed union of the tibial tuberosity following OWDTO. Furthermore, to prevent delayed union of the tibial tuberosity, postoperative onset LHFs should be prevented.

Level of evidence

LEVEL III, Case-control study.

Effect of lateral hinge fractures for bone union and clinical outcomes following opening-wedge distal tibial tubercle osteotomy in comparison with opening-wedge high tibial osteotomy

PURPOSE

Although the effects of lateral hinge fractures (LHF) on bone union and clinical outcomes after opening-wedge high tibial osteotomy (OWHTO) have been established, the effects of LHF after opening-wedge distal tibial tubercle osteotomy (OWDTO) are unclear. We hypothesised that LHF after OWDTO would be associated with delayed bone union and result in poorer clinical outcomes than expected for LHF after OWHTO.

METHODS

This study enrolled 100 patients, with 50 OWDTO patients (18 men; mean age, 63.2 years) and 50 OWHTO patients compared based on the propensity score matched analysis. The effect of LHF on bone union was compared between the groups. Clinical outcomes were assessed using the Lysholm score and the Knee Injury and Osteoarthritis Outcome Score (KOOS) at the mean follow-up of 28 months.

RESULTS

There was no between-group difference in the incidence rate of LHF. However, the rate of bone union at the anterior flange in the presence of an LHF was significantly lower in the OWDTO (26%) than in the OWHTO (80%) 3 months postoperatively (p < 0.05), but no difference was observed 12 months postoperatively. The Lysholm score was significantly lower for patients with LHF following OWDTO than for OWDTO patients without LHF or OWHTO patients with/without LHF 3 and 12 months postoperatively (p < 0.001); Lysholm score and KOOS were not different at the final follow-up.

CONCLUSIONS

LHF after OWDTO was associated with delayed bone union and poor clinical outcomes until 12 months. This information can guide decisions regarding the indications and the management of patients after OWDTO.

LEVEL OF EVIDENCE

IV.