Incidence and Factors Affecting the Occurrence of Lateral Hinge Fracture After Medial Opening-Wedge High Tibial Osteotomy

Editorial Commentary: Risk of Lateral Hinge Fracture After Knee Medial Opening-Wedge High Tibial Osteotomy Can Be Reduced With Osteotomy at the Level of the Proximal Tibiofibular Joint and Gap Width of No Larger Than 11 mm

Medial opening-wedge high tibial osteotomies are commonly performed to treat varus deformity and medial compartment osteoarthritis of the knee in active younger individuals. A common complication of this procedure is the development of a lateral hinge fracture. This can occur both acutely and with a delayed presentation. There are many considerations to reduce this fracture, including biplanar versus monoplanar osteotomy, amount of correction/gap width, level of the osteotomy, and lateral cortical distance of the osteotomy. To best reduce the risk of a lateral hinge fracture, place the level of the osteotomy at the level of the proximal tibiofibular joint, and maintain a gap width of no larger than ∼11 mm.

Lateral Distance From the Osteotomy Hinge Point to the Tibial Cortex Is Associated With Lateral Hinge Fracture Type and Fracture Occurrence Time After Medial Open-Wedge High Tibial Osteotomy

PURPOSE

To verify whether the distance from the hinge point to the tibial cortex affects the occurrence time and characteristics of the lateral hinge fracture (LHF) in medial open-wedge high tibial osteotomy.

METHODS

We retrospectively reviewed 171 knees in 171 patients (121 women, 50 men; mean age, 53.9 years; range, 36-67 years) who had undergone medial open-wedge high tibial osteotomy with locking plate fixation between January 2011 and December 2020. Osteotomy hinge point and LHFs were identified on intraoperative fluoroscopy and immediate postoperative radiographs. LHF type was classified as suggested by Takeuchi et al. Acute fracture was defined as a fracture that occurred during surgery, and delayed fracture was defined as a fracture observed after 1 month postoperatively. The nearest distances from osteotomy hinge point to lateral, distal, and proximal cortex were measured on postoperative radiographs. We compared the distance between the different types and between acute and delayed LHFs.

RESULTS

There were 55 LHFs (32%) (type I, 40 knees; type II, 14 knees; type III, 1 knee) that occurred acutely in 41 knees and were found as delayed fractures in 14 knees. The patient demographics were not significantly different between non-LHFs and each type of LHFs. Proximal and distal distances were not statistically different among fracture types and between occurrence times. However, lateral distances were significantly shorter in type I LHFs (6.2 ± 1.8 mm) and longer in type II LHFs (9.3 ± 2.3 mm) than in non-LHFs (7.1 ± 2.7 mm) (P = .020 and .004, respectively). The lateral cortical distances were also different between acute LHFs (6.4 ± 1.9 mm) and delayed LHF (9.0 ± 2.7 mm) (P < .001). In the case of fracture type, the frequency of type I decreases with increase in the lateral distance, whereas that of type II increases with increase in the lateral cortical distance. In acute fracture, type I was dominant (85.4%), whereas in delayed fracture, type II was dominant (57.2%).

CONCLUSIONS

The lateral cortical distance from the hinge point was significantly associated with LHF occurrence. Shorter distance increased the risk for acute type I LHF, whereas longer distance increased the risk for delayed type II LHFs.

LEVEL OF EVIDENCE

Level III, retrospective comparative prognostic trial.

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.

Higher fibular head is a risk for lateral hinge fracture in medial open wedge high tibial osteotomy

PURPOSE

To examine the association between the hinge position, fibular head position, and type III lateral hinge fracture (LHF) in patients with knee osteoarthritis (OA) who underwent medial open wedge high tibial osteotomy (MOWHTO).

METHODS

This retrospective study examined patients who underwent MOWHTO. Radiographically, the Kellgren-Lawrence (K/L) classification, distance between the articular surface and the tip of the fibular head (fibular head position), hinge point (hinge position), type of LHF, and safe zone (within the proximal tibiofibular joint) outlier were evaluated. To determine the cut-off value of the hinge position and fibular head position associated with type III LHF, a receiver operating characteristic (ROC) curve analysis was performed. The odds ratio (OR) was calculated from the obtained cut-off values using logistic regression, which was adjusted by age, gender, body mass index, and opening distance.

RESULTS

Among 132 knees in 120 patients, the radiographic severity of knee OA was 19 (14%), 73 (55%), and 40 (30%) of K/L grades 2, 3, and 4, respectively. LHF was observed in 40 knees (30%), including types I, II, and III fractures in 21 (16%), 5 (4%), and 14 (11%) knees, respectively. Hinge and fibular head positions were 16 and 10 mm, respectively, with significant correlation. Safe zone outlier was observed in 38 knees (29%). The hinge and fibular head positions with type III LHF were significantly higher (more cranial) than those with no fracture or other LHF subtypes. The ROC curve revealed that the cut-off value for the hinge and fibular head positions was 13.3 and 8.6 mm, respectively. The OR of the hinge and fibular head positions was 22.42 and 13.86, respectively.

CONCLUSIONS

A higher hinge position was a risk factor for type III LHF and was associated with a higher fibular head in patients with knee OA who underwent MOWHTO. The hinge position should be placed at a certain distance from the articular surface to avoid type III LHF, especially in participants with higher fibular head position, even if the hinge position is located in the safe zone.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

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

BACKGROUND

The aims of this study were (1) to compare the incidence of lateral hinge fractures (LHFs) in medial opening-wedge high tibial osteotomy (OWHTO) and medial opening-wedge distal tibial tuberosity osteotomy (DTO), and (2) to investigate the risk factors for LHFs. The incidence of LHFs was hypothesized to be higher in the DTO group than the OWHTO group. The DTO procedure is also a risk factor for LHFs.

METHODS

A total of 167 knees that underwent OWHTO (n = 65) and DTO (n = 102) were subjected to propensity score matching for the comparison of the groups. The matched variables were sex, preoperative hip-knee-ankle (HKA) angle, and preoperative medial proximal tibial angle. Forty-one matched pairs were enrolled for comparative analysis. Logistic regression analysis was performed to investigate risk factors for LHFs.

RESULTS

The incidence of LHFs was not significantly different between the groups (34.1% vs. 26.8%, respectively; p = 0.631). Logistic regression analysis showed that age (odds ratio: 1.074, 95% confidence interval (CI): 1.020-1.131, p = 0.007), BMI (odds ratio: 1.150, 95% CI: 1.049-1.260, p = 0.003), and preoperative HKA angle (odds ratio: 1.150, 95% CI: 1.049-1.260, p = 0.035) were significant risk factors for LHFs. The difference in surgical technique between OWHTO and DTO was not a risk factor for LHFs (p = 0.204).

CONCLUSIONS

The incidence of LHFs is similar in DTOs and OWHTOs, and the DTO procedure is not a risk factor for LHFs.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Lateral hinge fracture in medial opening wedge high tibial osteotomy: a narrative review

Lateral hinge fractures (LHF) are one of the most common complications of medial opening wedge high tibial osteotomy (MOWHTO), and are the leading cause of construct instability displacement, non-union, and varus recurrence after this procedure. To date, Takeuchi's classification is the most popular classification to describe this complication, and it can help surgeons to make intra and postoperative decisions. Opening medial gap width is the most recognized factor related to LHF occurrence. Recognizing the implications of LHF in patients' clinical and radiographic results has led many authors to propose surgical tips and the use of osteosynthesis materials such as K-wires and screws for its prevention, which should be considered when identifying risk factors for LHF during preoperative planning. The evidence for determining the optimal management of LHF is scarce and mostly supported by experts' opinions and recommendations; therefore, studies are still needed to identify the most appropriate behavior when dealing with such a complication.

Large Versus Small Opening Wedge High Tibial Osteotomies Performed With a Protective Wire Over the Lateral Hinge: Incidence of Lateral Hinge Fracture and Early Clinical Outcomes

BACKGROUND

The incidence of lateral hinge fractures (LHFs) during medial opening wedge high tibial osteotomy (MOW-HTO) is unacceptably high, especially with distractions >10 mm. LHFs result in malunion, loss of correction, and recurrence of symptoms adversely affecting clinical outcomes.

PURPOSE

(1) To investigate the incidence of LHF when a protective guide wire is utilized during MOW-HTO in small and large corrections and (2) to study the effect of correction size on early clinical outcomes.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective analysis was performed of 96 knees that underwent MOW-HTO between 2019 and 2020. A protective wire applied intraoperatively across the lateral hinge point before opening wedge distraction was performed for all patients. Patients were divided into 2 groups based on opening wedge sizes: group A (opening distraction <10 mm) and group B (opening distraction ≥10 mm). LHF and wound complications were recorded. Prospective Knee Score and Function Score (Knee Society), Oxford Knee Score, and Physical and Mental Component Summaries of the 36-Item Short Form Health Survey questionnaire were recorded preoperatively and at 6 months and 2 years after surgery.

RESULTS

Incidence of LHF was low in group A (n = 2; 6.1%) and group B (n = 3; 9.1%). A single case of intraoperative LHF was noted in each group, with each case resulting in a type 1 fracture. The incidence of postoperative fractures was comparable between groups (groups A vs B, n = 1 vs 2). At 6 months, clinical outcomes in group A were superior to those of group B (Knee Score, 85.7 ± 14.7 vs 73.1 ± 20.3, P = 0.028; Function Score, 73.5 ± 16.5 vs 63.1 ± 19.5, P = 0.047; Oxford Knee Score, 20.2 ± 4.7 vs 25.6 ± 8.5, P = 0.008; Physical Component Summary, 46.8 ± 8.1 vs 40.2 ± 10.9, P = 0.018). However, clinical outcomes were comparable at 2 years (P > .05).

CONCLUSION

A protective wire was associated with a low incidence of LHF, even in larger MOW-HTO corrections. Large corrections had poorer clinical outcomes as compared with small corrections at 6 months. However, clinical outcomes between groups were comparable at 2 years.

Predictive Factors for Lateral Hinge Fracture in Medial Closing Wedge Distal Femoral Osteotomy

BACKGROUND

Recent studies have reported that lateral hinge fracture (LHF) has a negative effect on bone healing at the osteotomy site after medial closing wedge distal femoral osteotomy (MCDFO). However, limited evidence exists in the literature regarding the predictive factors for LHF in MCDFO.

HYPOTHESIS

A large medial closing gap and a lateral hinge position in the supracondylar area would increase plain radiography-based and/or computed tomography (CT)-based LHF in MCDFO.

STUDY DESIGN

Case control study; Level of evidence, 3.

METHODS

We retrospectively evaluated 67 knees of 53 patients (mean age, 37.4 ± 16.9 years) who underwent MCDFO between May 2009 and June 2021. The surgical indications for MCDFO were genu valgum deformity combined with either lateral compartment osteoarthritis or recurrent patellar dislocation. The presence of LHF was evaluated based on immediate postoperative plain radiography and CT scans. The predictive factors for LHF in MCDFO were investigated using multivariate logistic regression analysis.

RESULTS

LHFs were identified in 21 knees (31.3%) through plain radiography and in 40 knees (59.7%) through CT. Multivariate logistic regression analysis showed that the medial closing gap and lateral hinge position were predictive factors for plain radiography- and CT-based LHF after MCDFO. Controlling for other variables, we found that an increase in the medial opening gap by 1 mm increased the likelihood of plain radiography-based LHF by a factor of 1.805 (95% CI, 1.291-2.525; P = .001) and CT-based LHF by 1.333 (95% CI, 1.003-1.772; P = .048). Moreover, a lateral hinge position in the supracondylar area increased the likelihood of plain radiography-based LHF by a factor of 9.870 (95% CI, 2.179-44.720; P = .003) and CT-based LHF by 5.686 (95% CI, 1.124-28.754; P = .036).

CONCLUSION

A large medial closing gap and lateral hinge position in the supracondylar area are associated with LHF in MCDFO. Care should be taken to prevent LHF in MCDFO with a large medial closing gap. Moreover, a lateral hinge position in the supracondylar area should be avoided to decrease the incidence of LHF in MCDFO.