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

IntroductionMedial open wedge high tibial osteotomy is a biological procedure for treating unicompartmental knee osteoarthritis. The literature repeatedly highlights the significance of preserving an intact lateral hinge during this procedure. We investigated the temporal course of distraction forces during distraction at the osteotomy site, aiming to quantitatively measure and analyse temporal changes in distraction forces at different distraction points for intact and fractured lateral hinges.Materials and MethodsThis biomechanical study was conducted on 10 human cadavers, which were divided into two groups: one with preserved 1 cm intact lateral cortexes (ILCs) and the other with completely osteotomised fractured lateral cortexes (FLCs). An experimental setup was custom designed to facilitate the required force measurement during distraction. The distraction forces were recorded with a force gauge at 0.5‐mm intervals throughout the distraction.ResultsThere was a significant difference between the ILC and FLC groups in distraction forces at all points (8–15 mm). The ILC group consistently exhibited higher distraction force values, with FLC recording values ranging from 8.8% to 13.2% of ILC's. Lateral hinge fractures caused an 86.7% reduction in the initial required force for distraction, significantly impacting the force required for distraction. The ILC group displayed a linear increase in the required distraction force up to 12.5 mm of distraction, which reached 3.7 times the initial value at 12.5 mm of distraction. The FLC group had lower baseline required distraction forces, following a relatively linear trend with more limited increases.ConclusionFLCs in medial opening wedge osteotomy are associated with significant reductions in the force required for distraction, and a sudden decrease in distraction force during distraction may indicate a lateral hinge fracture. Force measurement devices for use during distraction could offer valuable insights and provide surgeons with immediate warnings for LHFs.Level of EvidenceLevel IV.

Section: Introductionmentioning

confidence: 99%

“…In addition to the technical challenges of preserving lateral cortical hinges during MOWHTO procedures, another challenge is recognising LHFs intraoperatively or even postoperatively [ 6 , 16 ]. A recent systematic review reported 40% LHFs in one study, 10% of which were missed using plain radiographs and fluoroscopy [ 15 ].…”

Section: Introductionmentioning

confidence: 99%

Required force for distraction during medial opening wedge high tibial osteotomy may serve as a predictive indicator for lateral hinge fracture

Soykan,

Vahabi,

Kaya Biçer

et al. 2024

Patients aged 55 or older undergoing around the knee osteotomy have a higher rate of deep vein thrombosis but not overall early post‐operative complications

Olivieri,

Laso,

Pineda

et al. 2024

PurposeOsteotomies around the knee have been established as an effective method for treating varus or valgus malalignment associated with other knee pathologies in young and middle‐aged patients. There is limited literature regarding the risks and complications based on patient age. The purpose of this study is to determine whether age influences as a risk factor for developing intraoperative and early post‐operative complications in patients undergoing osteotomies around the knee.MethodsA consecutive series of patients over 18 years old who underwent distal femoral osteotomy (DFO) or high tibial osteotomy (HTO) with a minimum follow‐up period of 90 days were included. Demographic characteristics, surgical technique, intraoperative and post‐operative complications up to 90 days were identified. A statistical comparison based on age younger than 55 years or 55 years and older was conducted to determine if patient age acted as a risk factor in the development of complications.ResultsA total of 159 osteotomies were included, of which 129 were HTOs. The average age was 46.16 years, and 118 patients were younger than 55 years. Seven hinge fractures were identified as the only intraoperative complication, while the overall early post‐operative complication rate was 11.32%. The most frequent was deep venous thrombosis (DVT) in 5.66% of cases, followed by deep infection with a total rate of 2.52%. When performing the subgroup analysis by age, we observed a significantly higher rate of DVT in the group aged 55 years and older (p 0.036) (odds ratio 3.96 95% confidence interval 1.009–15.533; p 0.048); however, no significant differences were observed in the overall complication rate according to the age group of the patients.ConclusionsThis study reveals that in patients undergoing osteotomies around the knee, the most common post‐operative complication was DVT. The rate of DVT was significantly higher in patients aged 55 years and older, although no differences were observed in the overall complication rate according to the patients' age range.Level of evidenceLevel III (retrospective cohort study).

Finite element analysis confirms the optimal apex position in medial opening wedge high tibial osteotomy to avoid lateral hinge fracture

Osmani,

Gupta,

Earl

et al. 2024

PurposeLateral hinge fracture is a significant complication of medial opening wedge high tibial osteotomy. While fracture risk is closely associated with the osteotomy apex position, the optimum position remains variable within the literature. Our hypothesis is that stresses at the osteotomy apex predicted by finite element analysis can be used to identify an apex position which minimises intra and postoperative fracture risks.MethodsA finite element model was studied to investigate the effect of varying the hinge position on fracture risk and severity for a given bone geometry; variables analysed included stress, strain and micromotion levels. Nine further knee models were studied to assess the variability between patients' bone properties and examine the effect of apex location on strains.ResultsLateral hinge width and height significantly influence intra‐operative stress, strain, and fracture risk, while hinge width predominately determines postoperative stability. Wider hinges improve postoperative stability, but increase the likelihood of intra‐articular fractures. Aiming the apex at the fibular head height minimises strain. The osteotomy apex should be located such that the hinge width is equal to 13% of the medial‐lateral width to minimise apex stress and fracture risk while preserving sufficient bone at the hinge for stability. The height of the apex from the tibial plateau should maintain a minimum value of 16% of the medial‐lateral width to avoid intra‐articular fracture, with the apex below the fibula head if necessary. The size of the tibia does not alter the optimal location, making our findings applicable across all tibia sizes.ConclusionsOur study has investigated and verified a proposed optimal apex position, based upon fracture risk prediction and micromotion at the osteotomy apex. This is clinically useful due to the potential use of the apex point on preoperative 2D radiographs when planning surgery.Level of EvidenceNot applicable.