Hinge Fracture Research Articles

Evaluating the Effectiveness of a Structural Allograft in Medial Open Wedge High Tibial Osteotomy in Patients With and Without a Lateral Hinge Fracture.

A lateral hinge fracture is a common complication in medial open wedge high tibial osteotomy (MOWHTO) and is associated with delayed union or nonunion. A comparison of outcomes between patients with or without a lateral hinge fracture after MOWHTO with a structural allograft has not been investigated. To validate the outcomes of MOWHTO with a structural allograft, especially in the presence of a lateral hinge fracture. Case series; Level of evidence, 4. We conducted a single-surgeon cohort study at a tertiary referral hospital between April 2017 and August 2022 and included patients who had undergone MOWHTO with a structural allograft for isolated medial compartment osteoarthritis with genu varum. We compared the incidence of delayed union or nonunion events and functional scores between patients with a lateral hinge fracture and those without using the Fisher exact test and independent t test. A total of 88 MOWHTO procedures (77 patients) were analyzed. The overall incidence of lateral hinge fractures was 29.5% (n = 26), including type I (n = 20 [22.7%]) and type II (n = 6 [6.8%]). Notably, 42.3% (n = 11) of these fractures had not been detected intraoperatively but during the follow-up visits. The overall Knee Society Score (KSS), Knee Society Score-Function (KSS-F), and Western Ontario and McMaster Universities Arthritis Index (WOMAC) scores were 90.0 ± 10.0, 93.4 ± 10.8, and 93.8 ± 7.1 points, respectively. None of the patients had delayed union or nonunion, and none underwent a reoperation because of bony union problems. The functional scores (KSS, KSS-F, and WOMAC) were not different between patients who had a lateral hinge fracture and those who did not (P > .05). The routine use of a structural allograft was associated with satisfactory outcomes after MOWHTO, regardless of whether there was a lateral hinge fracture.

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

Lateral 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. A 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. Lateral 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. Our 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. Not applicable.

Intraoperative Complications in Medial Opening Wedge High Tibial Osteotomy.

Medial opening wedge high tibial osteotomy has been established for treatment of medial symptomatic knee arthrosis with varus malalignment in young and elderly but active patients. To obtain satisfactory results, it is essential for surgeons performing osteotomy to identify, prevent, and treat potential intraoperative adverse events. Lateral hinge fracture (LHF) is the most common intraoperative complication while popliteus artery injury is rare but limb-threatening. Computed tomography is the benchmark to detect LHF, the risk of which increased markedly with the opening gap larger than 11 mm. Setting the lateral hinge in a safe zone is the most important preventive measure. Medial long locking plate fixation may allow patients even with unstable hinge fractures to start early full weight bearing. Additional fixation of LHF is optional, and bone void filling is not routinely used. For protection of popliteus artery injury, flexing the knee joint is unreliable. It is paramount to place a protective retractor just behind the posterior tibial cortex toward the proximal tibiofibular joint before osteotomy, particularly in case of aberrant artery. A repertoire of surgical pearls is described in detail in this review to identify, prevent, and manage those intraoperative complications.

Risk factors for delayed bone union in opening wedge high tibial osteotomy.

The purpose of this study was to investigate the relationship between patient demographics and potential intraoperative factors and delayed bone union in opening wedge high tibial osteotomy (OWHTO). A retrospective review of 65 patients (37 females, 28 males; mean age: 60.1±10.1 years; range, 44 to 77 years) who underwent OWHTO using an angle-stable implant with beta-tricalcium phosphate gap filling between September 2016 and October 2019 was conducted. The osteotomy site was divided into five zones from the lateral hinge on anteroposterior radiographs, and we defined the zone in which bone healing was observed. The bone union area was assessed according to this definition at three, six, nine, and 12 months after surgery, and bone union was defined as union at the fourth zone or greater. A generalized estimating equations approach was employed to investigate longitudinal data pertaining to bone union area as a dependent variable. In addition, the association of bone union at six months postoperatively and predictors were evaluated using cross-sectional statistical methods. The categorical predictors included in the models were smoking, diabetes, hinge fracture, and autologous osteophyte grafting. The continuous variables included in the models were age, body mass index, opening gap width, and plate position. Smoking (odds ratio [OR]=0.478, p<0.01), large opening gap width (OR=0.941, p=0.014), and anterior plate placement (OR=0.971, p<0.01) were significantly associated with decreased bone union area. Union rate at six months in smokers was significantly lower compared to nonsmokers (16.6% and 67.8%, respectively; OR=0.10, p=0.023). Area under the curve in the receiver operating characteristic analysis for bone union at six months was 0.60 for gap width and 0.63 for plate placement. Smoking, large opening gap width, and anterior plate placement are risk factors for delayed bone union after OWHTO. Surgeons should avoid anterior placement of the plate and carefully consider other options for smokers and those who require a large correction.

Medial Closing Wedge High Tibial Osteotomy Accurately Corrects Genu Valgum without Iatrogenic Deformity or Complications: A Consecutive Series of Thirty-one Procedures.

Angular deformities of the tibia and femur lead to mechanical axis deviation (MAD) of the lower limb and malorientation of the joints adjacent to the deformity. The current study analyses the outcomes of using a medial closing wedge high tibial osteotomy (MCWHTO) for the management of genu valgum with high medial proximal tibial angle (MPTA), and combined MCWHTO with lateral opening-wedge distal femoral osteotomy (LOWDFO) in the setting of concomitant genu varum with low lateral distal femoral angle (LDFA). There were 18 high tibial osteotomy (HTO)-only and 13 combined HTO + distal femoral osteotomy (DFO) procedures performed. The primary radiographic outcome variables included postoperative MPTA and MAD (in mm). The accuracy of MAD correction was expressed as a percentage. The postoperative posterior proximal tibial angle (PPTA) and limb length discrepancy (LLD) were also measured as secondary radiographic outcome variables. The clinical outcome variables included intraoperative surgical complications (e.g., hinge fracture), all-causes for revision, union rate, time to union, and postoperative knee range of motion. Functional outcomes used included the LDSRS, PROMIS, and EuroQOL scores. The mean preoperative MPTA was 92.9° (SD = 1.81, range: 88-96). After surgical correction, the mean MPTA was 86.0° (SD = 1.80, range: 83-90) (p < 0.0001). The mean preoperative MAD was 32.5 mm (SD = 20.16, range: 10-77) lateral to the centre of the knee joint. The mean postoperative MAD was 2.44 mm medial to the centre of the joint (SD = 7.13, range: 13 medial - 15 lateral) (p < 0.0001). The mean change in MAD achieved through surgical correction was 38.16 mm (SD = 17.94, range: 13-77). The accuracy of MAD correction was 96.1% (SD = 0.06%, range: 81.25-100%). The time to unassisted WB was a mean of 75 days (SD = 44.5, range: 44-242).There was a single stable hinge fracture and one case of chronic regional pain syndrome diagnosed. There were no cases of non-union and no indications for revision surgery in any case. Medial closing wedge high tibial osteotomy is an effective surgical procedure for the management of genu valgum deformity. The MPTA, LDFA, and MAD can be accurately corrected without significantly altering PPTA or limb length. It may be combined with open lateral distal femoral osteotomy for cases with femoral and tibial contributions to deformity without significantly impacting clinical outcomes. Functional outcomes, specifically relating to self-image are significantly improved after the MCWHTO has been performed. Sheridan GA, Page BJ, Greenstein MD, et al. Medial Closing Wedge High Tibial Osteotomy Accurately Corrects Genu Valgum without Iatrogenic Deformity or Complications: A Consecutive Series of Thirty-one Procedures. Strategies Trauma Limb Reconstr 2024;19(2):82-86.

Clinical course and risk factors for post-operative onset lateral hinge fracture following medial opening-wedge distal tibial tuberosity osteotomy

PurposeThis study aimed to investigate the clinical outcomes of and risk factors for post-operative onset lateral hinge fracture (LHF) following medial opening-wedge distal tibial tuberosity osteotomy (DTO). MethodsA total of 68 patients who underwent DTO were stratified into non-LHF and post-operative onset LHF groups. The groups were compared in terms of radiographic parameters, including the hip–knee–ankle (HKA) angle, and were clinically evaluated using the Knee Society Score (KSS) and 2011KSS. Multiple logistic regression analysis was performed to identify risk factors for post-operative onset LHF. ResultsThe non-LHF and post-operative onset LHF groups included 53 and 15 patients, respectively. The post-operative HKA angle was significantly smaller (valgus) in the post-operative onset LHF group than in the non-LHF group (P ​= ​0.005). Knee and function scores were significantly lower in the post-operative onset LHF group than the non-LHF group at 6 months (P ​= ​0.002 for each comparison). All 2011KSS subscores were significantly lower in the post-operative onset LHF group than the non-LHF group at 6 months (P ​= ​0.001, 0.010, 0.013, and 0.013, respectively). Post-operative HKA angle was a risk factor for post-operative onset LHF (odds ratio ​= ​0.589, 95% confidence interval 0.392–0.886; P ​= ​0.011). ConclusionsPost-operative weight bearing may be delayed to prevent post-operative onset LHF, especially in patients with post-operative large valgus knee alignment.

The new proposal of the relationship between axial pain and hinge fracture and facet involvement after open-door laminoplasty with titanium spacers

ABSTRACT Study Design: This was a retrospective, observational study. Objectives: Postoperative axial pain (AP) is a well-known complication of cervical posterior surgery. It can be caused by various reasons, but the etiology remains unclear. This study aimed to investigate risk factors for postoperative AP after open-door laminoplasty. A previous meta-analysis revealed muscle damage, female, age of &lt;60 years, and longer collar application as possible risk factors for postoperative AP after cervical posterior procedures. However, the postoperative AP etiology, specifically for open-door laminoplasty, has been inconclusive and remains conflicting. Methods: This retrospective study included 129 adult patients who underwent open-door cervical laminoplasty for degenerative diseases in our single institution from January 2015 to October 2021. Postoperative AP was defined as intolerable pain on the neck or shoulder that lasted for &gt;1 month postoperatively. We compared the demographic and radiographic characteristics of AP and non-AP groups. Results: Postoperative AP developed in 62 (48.1%) patients. Intraoperative hinge fracture (HF) and facet involvement by miniscrews were significantly greater in the AP group than in the non-AP group (P &lt; 0.05). Using a logistic regression model, multivariate analysis revealed that HF was significantly associated with postoperative AP (odds ratio = 2.83, 95% confidence interval = 1.28–6.44, P = 0.011). Conclusions: HF and facet involvement were risk factors for postoperative AP after open-door laminoplasty with titanium spacers. Careful surgical manipulation is required to prevent postoperative AP.

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.

Osteotomies 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. A 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. A 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. This 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 III (retrospective cohort study).

Gap Volume Based on Computed Tomography Measurement Is a Strong Risk Factor for Delayed Gap Healing After Open-Wedge High Tibial Osteotomy

To identify factors that affect delayed gap healing after open-wedge high tibial osteotomy (OWHTO) and to determine whether large gap volume is a predictor of delayed gap healing. This retrospective study analyzed biplane OWHTO performed between 2019 and 2023 for knee osteoarthritis or osteonecrosis. The minimum follow-up period was 1 year. Delayed gap healing was defined when the medial half of the osteotomy gap area had not reached the consolidation phase by 6 months after surgery based on anteroposterior knee radiographs. Gap volume was calculated from computed tomography images. Logistic regression was performed using body height, smoking, correction angle, hinge fracture, flange thickness, and gap volume. A gap volume cutoff value for delayed gap healing was determined with receiver operating characteristic curve analysis. Gap volume was predicted with multiple linear regression. There were 80 knees in 71 patients (36 men and 44 women). The mean gap volume was 7.6 cm3. Gap healing rates at 3, 6, 9, and 12 months after surgery were 26%, 65%, 89%, and 100%, respectively. There were 25 knees with delayed gap healing. Male sex was not a significant risk factor when adjusted for body height. Multivariate logistic regression revealed that only larger gap volume was a significant risk factor (odds ratio, 1.45; P= .006). The gap volume cutoff value was 7.6 cm3, with an area under the curve of 0.74. Tall body height and a large correction angle (both P < .001) were associated with a significantly larger gap volume (R2= 0.73). Large gap volume is the most important risk factor for delayed gap healing after OWHTO. Gap volume can be predicted based on body height and correction angle. When OWHTO with substantial correction is planned for tall men, surgeons should be aware of possibly delayed gap healing. Level IV, retrospective case-control study.

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

Medial 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. This 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. There 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. FLCs 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 IV.

Poster 238: Accuracy, Safety, and Cost of Patient-Specific Cutting Guides for Alignment-Correcting Osteotomy

Objectives: The purpose of this study was to determine the cost, accuracy of radiographic correction, and safety with respect to complication rates and fluoroscopic usage in patient-specific cutting guides (PSCG) osteotomies compared to an age- and body mass index (BMI)-matched group of controls using standard cutting guides (SCG). Methods: Patients were retrospectively reviewed between 2017 and 2022 at a single urban academic institution. Patients undergoing high tibial osteotomy (HTO) or distal femoral osteotomy (DFO) with PSCG (Bodycad 3d, Quebec, Canada) were identified. Traditional osteotomies were selected for the SCG group using propensity matching based on age, sex, BMI, osteotomy type. All procedures were performed by 1 of 2 fellowship-trained sports orthopaedic surgeons. Procedure time, fluoroscopy time, tourniquet time, and concomitant procedures were extracted from operative notes. Blinded, 2-reader hip-knee-ankle (HKA), posterior tibial slope (PTS) and mechanical axis deviation (MAD) measurements were performed on pre- and postoperative weightbearing radiographs for each procedure. Intraclass correlation coefficients (ICCs) were calculated to determine the reliability between the intended intraoperative correction of HKA and/or PTS the measured result on postoperative radiographs. A time-driven activity-based costing (TDABC) analysis was performed to compare costs of PSCG versus SCG. Results: Forty-two patients were included in the final analysis. Each group was 47.6% female, with 11 HTOs and 10 DFOs performed in each group. Final HKA (2.7° vs 1.9°, p = 0.355), PTS (1.6° vs 2.6°, p = 0.794) and MAD (10.2 vs 5.8 mm, p = 0.214) did not significantly differ between SCG and PSCG groups (MAD seems higher for SCG. The ICC between the intended and measured HKA correction was 0.841 (good) in the PSCG group and 0.623 (moderate) in the SCG group. PSCG osteotomies averaged 18.5 minutes less (p = 0.392) and required 16.7 minutes less tourniquet time (p = 0.121). Fluoroscopy time was significantly lower in the PSCG group compared to SCG (99 vs 43 seconds, p &lt; 0.001), as well as radiation dose (7.8 vs 2.9 mGy, p = 0.013). TDABC analysis demonstrated a base cost of $21,067 for PSCG and $23,896 for SCG. When the cost of the cutting guide and pre-operative imaging were included, PSCG was $2,829 more expensive than SCG. There was a lower, though non-statistically significant, rate of hinge fractures (9.5% vs 33.3%, p = 0.130) and return to the OR (4.8% vs 19.0%, p = 0.343) when comparing PSCG and SCG groups. Conclusions: Both traditionally guided osteotomies and PSCG-guided osteotomies accurately corrected lower extremity malalignment. Utilization of PSCG resulted in similar procedure times and cost. PSCG required less fluoroscopy and resulted in less radiation to conventional osteotomy and trended toward a decreased rate of postoperative complications.

Core Reduction Methods of Mizyn Industry of Epigravettian Techno-Complex

Mizyn is one of the main sites of the Epigravettian techno-complex of the Middle Dnipro Basin. One of the modern approaches to the study of the material culture of Upper Palaeolithic societies is the study of technological features of flintknapping. The purpose of this study is to determine the core reduction strategy of the Mizyn site in particular and the Mizyn industry in general. To achieve this goal, an attributional analysis of the artefacts from the lithic assemblage of excavation area no. 1 of the Mizyn site was carried out. Fragments of raw material, core-like pieces, and lamellar pieces have been analysed. This paper focuses on the study of the assemblage of core-like pieces, taking into account the imperfections of the 70-year-old field research methodology. The main outcome of this study was the elucidation of discrete core reduction strategies of the Mizyn site. Rounded raw material played a greater role in the production of blades from narrow flaking surface cores and sub-cylindrical cores (fig. 4). Narrow flaking surface cores (fig. 6) made from plate-like raw materials were used to produce blades and micro-blades. Blades were necessary blanks for making a “home” set of tools. Bladelets and micro-blades were used for hunting equipment. Both strategies are characterised by unidirectional splitting and the use of the hard hammer-stone. Crested and débordante lamellar pieces were required to maintain the convexity of the core’s flaking surface. The overhang trimming method was also used, most commonly for bladelets and micro-blade cores. The main reason for core discard was the occurrence of hinge fractures on the flaking surface, which were repaired by using an opposite striking platform. The same features of the lithic assemblage are found at the Barmaky site. As a result, discrete strategies of the core reduction are a typical feature for the Mizyn industry. As Barmaky and Mizyn are the oldest Epigravettian sites in the Middle Dnipro basin, this feature can be explained by a chronological factor. However, the choice of a strategy can also be explained by the regional characteristics of the landscape and the adaptation of the primary inhabitants to them.

High tibial osteotomy versus unicompartmental knee arthroplasty in advanced medial compartmental knee arthrosis: A comparative study with propensity score matched analysis

BackgroundIsolated knee medial compartmental osteoarthritis(MOA) can be treated with High Tibial Osteotomy (HTO) or Unicompartmental Knee Arthroplasty (UKA).This study aims to describe and compare outcomes of HTO and UKA in patients with isolated severe MOA. The authors hypothesized that similar outcomes can be achieved. MethodsData was collected prospectively of HTOs and UKAs performed between January-2016 and April-2021 by a knee surgeon. Oxford Knee Score (OKS), Knee Society Knee Score (KSKS) and Function Score (KSFS) were collected pre-operatively, six-months and two-years post-surgery. OA severity was graded on pre-operative radiograph. Medial Proximal Tibia Angle (MPTA), Lateral Distal Femoral Angle (LDFA), Joint Line Convergence Angle (JLCA) and Hip-Knee-Ankle Angle (HKAA), were measured on full-length radiograph.47 HTO and 74 UKA were included. Propensity score matching was performed, accounting for preoperative scores, age, gender and body mass index (BMI), before statistical analysis. Level of significance was set at 0.05. ResultsBoth groups were similar in age(56.42 vs 58.57, p = 0.067), BMI(29.82 vs 29.09, p = 0.484), gender distribution (p = 0.663) and laterality (p = 0.836).Pre-operatively, both groups were similar in clinical scores and lower limb alignment. On follow-up, both groups achieved similar improvements in clinical scores. However, the HTO group reported poorer extension at 6-months (7.91° vs 4.80°, p = 0.013) and 2-years (5.57° vs 3.24°, p = 0.018).Three cases of hinge fracture and six cases of implant removal occurred in the HTO group. One case of tibial fracture occurred in the UKA group. ConclusionsIn severe MOA, similar outcomes were achieved with HTO and UKA at two years.

Influence and risk factors of lateral hinge fracture on early effectiveness of supramalleolar osteotomy

To evaluate the influence of lateral hinge fracture (LHF) on the early effectiveness of supramalleolar osteotomy (SMO) and to explore the related risk factors for LHF. A total of 39 patients (39 feet) with varus-type ankle osteoarthritis treated with SMO between January 2016 and December 2022 were analyzed retrospectively. There were 10 males and 29 females, aged from 41 to 71 years (mean, 57.7 years). According to Takakura stage, there were 6 feet in stage Ⅱ, 19 feet in stage Ⅲa, and 14 feet in stage Ⅲb. The LHF was recognized by the immediate postoperative X-ray film. The osteotomy healing time and the changes of pain visual analogue scale (VAS) score, American Orthopaedic Foot and Ankle Society (AOFAS) score, tibial anterior surface angle (TAS), tibial lateral surface angle (TLS), and tibiotalar angle (TT) before and after operation were compared between patients with and without LHF. The age, gender, affected side, body mass index, Takakura stage, preoperative VAS score, preoperative AOFAS score, preoperative TAS, preoperative TLS, preoperative TT, SMO correction angle, osteotomy distraction, distance from medial osteotomy to ankle joint line (MD), and distance from lateral osteotomy to ankle joint line (LD) were compared between with and without LHF patients, and further logistic regression analysis was used to screen the risk factors of LHF during SMO. All patients were followed up 12-54 months (mean, 27.1 months). During operation, 13 feet developed LHF (group A) and 26 feet did not develop LHF (group B). X-ray film reexamination showed that 1 patient in group A complicated with tibial articular surface cleft fracture had delayed osteotomy and healed successfully after plaster fixation; the osteotomy of other patients healed, and there was no significant difference in healing time between the two groups ( P>0.05). At last follow-up, there were significant differences in VAS score, AOFAS score, TAS, TLS, and TT of the two groups when compared with preoperative ones ( P<0.05), but there was no significant difference in the changes of above indicators before and after operation between the two groups ( P>0.05). The differences in SMO correction angle, osteotomy distraction, and LD between with and without LHF patients were significant ( P<0.05), and further logistic regression analysis showed that excessive LD was the risk factor of LHF during SMO ( P<0.05). Too high or too low lateral hinge position during SMO may lead to LHF, but as long as appropriate treatment and rehabilitation measurements are taken, the early effectiveness is similar to that of patients without LHF.

Effects of intraoperative hinge fracture on postoperative cervical spine alignment in double door cervical laminoplasty

Introduction Hinge fracture and cervical kyphosis are known complications of cervical laminoplasty. Prior literatures on hinge fracture focused mainly on laminoplasty performed using the open-door technique. In this study we aim to assess the effect of intraoperative hinge fracture on postoperative cervical spine alignment in cervical laminoplasty performed using the double door technique. Methods This study recruited patients who received double door cervical laminoplasty from January 2014 to December 2022. The diagnosis, demographic data, preoperation and postoperation cervical spine alignment of the patients with intraoperative hinge fracture were compared with patients withouintraoperative hinge fracture. Cervical spine alignment was measured using C2–7 Cobb's angle on neutral lateral cervical spine X ray. Results Nine patients with intraoperative hinge fracture and 51 patients without intraoperative hinge fracture were recruited into the study. There was no statistically significant difference in age, sex, diagnosis and preoperative cervical spine alignment between the patients with and without intraoperative hinge fracture. Significant difference was found in the postoperation cervical spine alignment (1.9 ± 15.5° vs 9.7 ± 13.6°, p = .044) and change in cervical spine alignment (−12.9 ± 12.1° vs −4.0 ± 10.0, p = .02) between patients with and without intraoperative hinge fracture. Conclusions In double door cervical laminoplasty, intraoperative hinge fracture is associated with development of postoperative cervical kyphosis.

Larger lateral hinges increase the probability of Takeuchi type II and III fractures in high tibial osteotomy.

Lateral hinge fractures are the main complications in the high tibial osteotomy to treat varus deformities. The aim of present study is to answer the question whether the lateral hinge length (H) has an effect on the type of fracture and required force during the opening in high tibia osteotomy. It was hypothesized in this comparative research that extending the hinge length increased opening force and probability of a type II and type III fractures. A monoplanar medial open wedge osteotomy with different intact hinge lengths varying from 9 to 32mm was performed in 20 ostrich bones. A biomechanical experiment using unidirectional tensile testing apparatus was performed to open the wedge, and the required force was increased until a 10mm opening was reached; then, the presence of fracture in the lateral cortex and its direction were evaluated. Lateral hinge fracture type based on direction was classified as suggested by Takeuchi etal. Fracture that grows along the osteotomy line (type I) was observed in 4 samples with the mean hinge length (H) of 11 ± 1.54mm. For seven bones with Takeuchi fracture type II, with downward crack propagation, the mean H was 16 ± 3.36mm. For the mean H of 25 ± 6.53mm, the crack propagated upward to the cutting path, displaying a Takeuchi type III fracture in seven samples. The statistical analysis showed that the fracture type significantly depends on the hinge length (P value < 0.05). Also, the mean opening force significantly increased with hinge lengthening (P value < 0.05). The peak forces at crack initiation were 41.8 ± 21.9, 115.2 ± 41.5, and 167 ± 135.3 N, respectively, for the fracture types I, II, and III samples. The lateral cortical hinge length was significantly associated with hinge fracture type. The experimental tests indicated that the hinge lengthening increases the risk of type II and III fractures, as classified by Takeuchi.

Bone substitute fracture in open wedge high tibial osteotomy: Comparison of two different bone substitutes

PurposeThe aim of this study was to retrospectively compare bone substitute fracture patterns and outcomes in patients who underwent open wedge high tibial osteotomy (OWHTO) with OSferion60 or OSferion60 Marvelous bone substitutes. Patients with and without bone substitute fractures were compared and risk factors for bone substitute fracture were identified. MethodsIncluded patients were physically active non-smokers with knee osteoarthritis and deformity in the proximal tibia, persistent pain, and <5° of flexion contracture. OWHTO was performed with a TriS plate and a target femorotibial angle (FTA) of 170°. Full weight-bearing began the day after surgery. Pre-, intra-, and post-operative evaluations of demographic, clinical, and radiological factors were performed. Regression analysis was performed to identify risk factors for bone substitute fracture. ResultsData for 63 patients were analyzed (OSferion60, n ​= ​28 and Marvelous, n ​= ​35; bone substitute fracture, n ​= ​32 and non-bone substitute fracture, n ​= ​31). No significant differences were found between the bone substitute groups in patient characteristics and pre-operative and 2-year FTA, Japanese Orthopaedic Association (JOA) score, and flexion range. FTA and JOA scores improved significantly 2 years post-operatively (both p ​< ​0.001). There were 32 bone substitute fractures (OSferion60, n ​= ​20; Marvelous, n ​= ​12); all occurred by the 1-month follow-up. Gap filling occurred significantly earlier in the Marvelous group versus the OSferion60 group (p ​< ​0.001). Risk factors for bone substitute fracture were weaker bone substitute [odds ratio (OR) ​= ​8.34; p ​< ​0.001] and lateral hinge fracture (OR ​= ​11.7; p ​= ​0.045). ConclusionsAlthough bone substitute fracture was common in both bone substitute groups, this did not affect outcomes. However, lateral hinge fractures are a particular concern.

Faster Bone Gap Union in Medial Opening Wedge High Tibial Osteotomy With 3D-Printed Synthetic Bioresorbable Polycaprolactone and Tricalcium Phosphate Osteotomy Gap Fillers Compared to Allogeneic Osteotomy Gap Fillers: A Retrospective Matched-Pair Cohort Study.

The use of synthetic bone substitute material (BSM) as osteotomy gap fillers have been reported to improve outcomes in medial opening wedge high tibial osteotomy (MOWHTO). This study aims to evaluate the early radiological outcomes (bone union) and complication rates of the novel patient-specific 3D-printed honeycomb-structured polycaprolactone and tricalcium phosphate (PCL-TCP) synthetic graft compared to allogeneic bone grafts as an osteotomy gap filler in MOWHTO. A retrospective matched-pair analysis of patients who underwent MOWHTO with either PCL-TCP synthetic graft or allogenic femoral head allograft as osteotomy gap filler was performed. The osteotomy gap was split into equal zones (Zone 1-5), and bone union was evaluated on anteroposterior radiographs based on the van Hemert classification at 1, 3, 6, and 12 months postoperatively. Postoperative complications including infection, lateral hinge fractures, and persistent pain was measured. The study and control group were matched for age, smoking status, diabetes mellitus, and osteotomy gap size. Significantly greater bone union progression was observed in the PCL-TCP group than in the allograft group at 1 month (Zones 1-3), 3 months (Zones 1-4), 6 months (Zones 1-2, 4), and 12 months (Zones 2-3, 5) postoperatively (P < 0.05). No significant difference in complications rates was noted between the two groups at 1 year. Bone union rates observed in patients who underwent MOWHTO with the PCL-TCP synthetic graft osteotomy gap filler were superior to those in the allograft group at 1 year postoperatively, with no significant difference in complication rates (postoperative infection, lateral hinge fractures, and persistent pain).

Setting hinge position distal to the proximal margin of the distal lateral femur reduces the maximum principal strains of the hinge area and risk of hinge fractures.

The optimal hinge position to prevent hinge fractures in medial closing wedge distal femoral osteotomy (MCWDFO) based on the biomechanical background has not yet been well examined. This study aimed to examine the appropriate hinge position in MCWDFO using finite element (FE) analysis to prevent hinge fractures. Computer-aided design (CAD) models were created using composite replicate femurs. FE models of the MCWDFO with a 5° wedge were created with three different hinge positions: (A) 5 mm proximal to the proximal margin of the lateral epicondylar region, (B) proximal margin level and (C) 5 mm distal to the proximal margin level. The maximum and minimum principal strains in the cortical bone were calculated for each model. To validate the FE analysis, biomechanical tests were performed using composite replicate femurs with the same hinge position models as those in the FE analysis. In the FE analysis, the maximum principal strains were in the order of Models A > B > C. The highest value of maximum principal strain was observed in the area proximal to the hinge. In the biomechanical test, hinge fractures occurred in the area proximal to the hinge in Models A and B, whereas the gap closed completely without hinge fractures in Model C. Fractures occurred in an area similar to where the highest maximal principal strain was observed in the FE analysis. Distal to the proximal margin of the lateral epicondylar region is an appropriate hinge position in MCWDFO to prevent hinge fractures. Level V.

Soft Tissue Stabilization of the Hinge Position for Lateral Closing-Wedge Distal Femoral Osteotomy: An Anatomic Study.

Soft tissue plays an important role in stabilizing the hinge point for osteotomy around the knee. However, insufficient data are available on the anatomic features of the soft tissue around the hinge position for lateral closing-wedge distal femoral osteotomy (LCWDFO). To (1) anatomically analyze the soft tissue around the hinge position for LCWDFO, (2) histologically analyze the soft tissue based on the anatomic analysis results, and (3) radiologically define the appropriate hinge point to prevent unstable hinge fracture based on the results of the anatomic and histological analyses. Descriptive laboratory study. In 20 cadaveric knees (age, 82.7 ± 7.8 years; range, 60-96 years), the soft tissue of the distal medial side of the femur was anatomically analyzed. The thicknesses of the periosteum and direct insertion of the adductor tendon (AT) were histologically examined and measured using an electron microscope. The thickness of the periosteum was visualized graphically, and the graph of the periosteum and radiograph of the knee were overlaid using image editing software. The appropriate hinge position was determined based on the periosteal thickness and attachment of the AT. The mean thickness of the periosteum of the metaphysis was 352.7 ± 58.6 µm (range, 213.6-503.4 µm). The overlaid graph and radiograph revealed that the thickness of the periosteum changed at the part corresponding to the transition between the diaphyseal and metaphyseal ends of the femur. The mean width of the AT attached to the distal medial femur from the adductor tubercle toward the distal direction was 7.9 ± 1.3 mm (range, 6.3-9.7 mm). Results indicated that the periosteum and AT support the hinge for LCWDFO within the area surrounded by the apex of the adductor tubercle and the upper border of the posterior part of the lateral femoral condyle. When the hinge point is located within the area surrounded by the apex of the adductor tubercle and the upper border of the posterior part of the lateral femoral condyle, these soft tissues work as stabilizers, and there is no risk of cutting into the joint space.