Medial Tibial Cortex Research Articles

Validity of the Center-Center Method for Syndesmotic Fixation Axis Against the Trans-Syndesmotic Axis: A Cross-Sectional Study

Category: Trauma; Ankle Introduction/Purpose: In surgery for ankle fractures with tibiofibular diastasis, it is important to vertically grasp the distal tibiofibular joint. However, it is difficult to do that because the tibiofibular joint surface is not under direct vision. Center-center method (CC) is an intraoperative fluoroscopic technique to determine the position of the syndesmotic clamp. CC has been reported to reduce the risk of syndesmotic malreduction, but It is unclear whether the axis by CC (CC axis) coincides with the axis perpendicular to the distal tibiofibular joint (trans-syndesmosis axis: TS axis). Therefore, the present study aims to 1) measure the difference between the CC axis and TS axis, and 2) compare the measured values when CC is performed at different distances from the ankle joint surface. Methods: The subjects were 150 patients who underwent CT scans for ankle joint disease and lower extremity trauma. CC is a method in which the ankle joint is rotated, and the midpoint of the anteroposterior margin of the tibia and fibula is superimposed by fluoroscopy. In the present study, CC was performed using Digitally reconstructed radiography (DRR) created from a CT image. At the ankle joint surface (0mm), CC axis and TS axis were projected onto the CT axis linked with DRR. The angle between the axes was measured (inter-axes angle). Also, the distance of the intersection of these axes through the medial cortex of the tibia was measured (inter-axes distance). It was also performed at 10mm and 20mm proximal to the ankle joint surface. One-way repeated measures analysis of variance and the post hoc Bonferroni tests were used to compare the measured values' difference according to the articular surface's height. Results: Overall, the TS axis was externally rotated relative to the CC axis, with a mean inter-axes angle of 8.5±6.8degrees. The inter-axes angle of 0mm, 10mm, and 20mm were 1.9±4.0degrees, 10±5.3degrees, and 13±5.1degrees, respectively (p < 0.001). Also, the intersection point of the TS axis with the medial tibial cortex was anterior to the intersection of the CC axis, with an inter-axes distance of 7.7±6.3mm overall. The inter-axes distance of 0mm, 10mm, and 20mm were 2.0±4.2mm, 9.0±4.9mm, and 11.3±5.2mm, respectively (p < 0.001). Both the inter-axes angle and the inter-axes distance were larger when the CC method was performed higher to the tibial plafond (P < .001), with the post hoc tests showing significant differences among all heights. Conclusion: The TS axis was externally rotated to the CC axis and positioned slightly anteriorly. Also, the inter-axes angle and distance were larger when the CC method was performed higher to the tibial plafond. If the surgeon aimed to clamp the syndesmosis along the TS axis, the CC method should be applied closer to the ankle joint surface, and the medial tip of the forceps be placed slightly anterior to the point determined by the CC axis.

Validity of the Center-Center Method for the Syndesmotic Fixation Axis Compared to the Transsyndesmotic Axis.

Placement of clamp forceps along the transsyndesmotic (TS) axis reduces the risk of iatrogenic syndesmotic malreduction during ankle fracture surgery with tibiofibular diastasis. This study aimed to measure the difference between the TS axis and the axis determined by an intraoperative fluoroscopic technique using the center-center (CC) method. We also compared the values obtained when the CC method was performed at different heights from the tibial plafond. We evaluated the computed tomography scans of 150 patients with normal syndesmosis. The CC method was simulated using digitally reconstructed radiographs. The TS and CC axes were projected onto an axial computed tomographic image linked to digitally reconstructed radiography. The angle between the two axes (interaxis angle) and the distance between the intersection of these axes and the medial tibial cortex (interaxis distance) were measured. The procedures were performed 0, 10, and 20 mm proximal to the tibial plafond, and the measurements were compared among the different heights using a 1-way repeated-measures analysis of variance. The TS axis was found to be externally rotated to the CC axis, with an interaxis angle of 8.5 degrees (SD, 6.8 degrees). The interaxis angle increased from 1.9 degrees at a height of 0 mm to a greater angle at higher heights (P < .001). The overall interaxis distance was 7.7 (SD, 6.3) mm, increasing from 2.0 mm at a height of 0 mm to a greater distance at higher heights (P < .001). The TS axis was externally rotated relative to the CC axis, and the difference between the 2 axes was greater when the CC method was performed on the higher heights from the tibial plafond. To clamp the syndesmosis along the TS axis, the CC method should be applied close to the ankle joint. Level IV, case series.

Restricted Kinematically Aligned Total Knee Arthroplasty Following Failed Oxford Unicompartmental Knee Arthroplasty.

In this report, we describe how to revise a failed Oxford unicompartmental knee arthroplasty to kinematically aligned total knee arthroplasty (TKA). Its benefits are the maintenance of the native joint line along with the avoidance of supplemental parts, such as metal augments and stems. This can be applied to patients whose medial tibial cortex is well preserved. The distal cutting plane and rotation alignment are decided before the removal of the femoral component. The tibial cutting plane is up to 12 mm below the lateral joint surface and the varus is up to 5° below the extramedullary rod. Eventually, the native joint line and alignment along with the soft tissue envelope can be well maintained, similar to the restricted kinematically aligned TKA.

Can ultrasound-guided radiofrequency ablation of genicular nerves of the knee, be performed without locating corresponding arterial pulsations—a cadaveric study

IntroductionGiven the rising prevalence of knee osteoarthritis, radiofrequency ablation of genicular nerves (RFA) has emerged as a promising treatment option for knee pain. The knee has an extremely complex and variable innervation with nearly 13 genicular nerves described. The frequently ablated genicular nerves are the superomedial (SMGN), the superolateral (SLGN), and the inferomedial (IMGN) genicular nerves. Conventionally, under ultrasound guidance, these nerves are ablated near the corresponding arterial pulsations, but due to the rich vascular anastomosis around the knee joint, identifying the arteries corresponding to these constant genicular nerves can be tedious unless guided by some bony landmarks. In this study, we have evaluated whether it is possible to accurately target these three genicular nerves by just locating bony landmarks under ultrasound in human cadaveric knee specimens.MethodsFifteen formalin-fixed cadaveric knee specimens were studied. SMGN was targeted 1 cm anterior to the adductor tubercle in the axial view. For SLGN, in the coronal view, the junction of the lateral femoral condyle and shaft was identified, and at the same level in the axial view, the crest between the lateral and posterior femoral cortex was targeted. For IMGN in the coronal view, the midpoint between the most prominent part of the medial tibial condyle and the insertion of the deep fibers of the medial collateral ligament was marked. The medial end of the medial tibial cortex was then targeted at the same level in the axial view. The needle was inserted from anterior to posterior, with an in-plane approach for all nerves. Eosin, 2% W/V, in 0.1 ml was injected. Microdissection was done while keeping the needle in situ. Staining of the nerve was considered a positive outcome, and the percentage was calculated. The nerve-to-needle distance was measured, and the mean with an interquartile range was calculated.ResultThe accuracies of ultrasound-guided bony landmarks of SMGN, SLGN, and IMGN were 100% in terms of staining, with average nerve-to-needle distances of 1.67, 3.2, and 1.8 mm respectively.ConclusionIt is with 100% accuracy, that we can perform RFA of SMGN, SLGN, and IMGN under ultrasound guidance, by locating the aforementioned bony landmarks.

Medial proximal tibial resorption after total knee arthroplasty according to the design of the cobalt chrome tibial baseplate.

A new tibial baseplate of the cobalt-chrome (CoCr) prosthesis has an enhanced design with additional cement pockets and undersurface with increased roughness compared with the original baseplate. This study aimed to compare the incidence of medial proximal tibial resorption (MPTR) in total knee arthroplasties (TKAs) with the original and new CoCr tibial baseplates. Each of 200 posterior stabilized TKAs with the original (Group O) and new (Group N) CoCr tibial baseplates with a minimum follow-up period of 2years were retrospectively reviewed. The matches were made according to age, sex, body mass index, and severity of varus deformity. The occurrence of MPTR was investigated with a radiograph at 2years postoperatively. MPTR was categorized as type U (resorption under the tibial baseplate; associated with stress shielding), C (resorption around the penetrated cement under the baseplate; associated with thermal necrosis), and M (resorption on the medial tibial cortex without extension to the baseplate; associated with bony devascularization). The incidence of MPTR was 35% in group O and 24% in group N (p = 0.021) at postoperative 2years. The U type of MPTR occurred more frequently in group O (26 vs. 15%, p = 0.009). There were no significant differences in the incidence of types C and M MPTR. The modified design of the CoCr tibial baseplate affected the incidence of MTPR. The new tibial baseplate was more advantageous in preventing MPTR than the original baseplate in TKAs using the CoCr prosthesis. III.

Medial tibial plateau fracture following unicompartmental knee arthroplasty – characteristics, risk factors, pathogenesis and treatment methods. Literature review and case report

Introduction. Medial tibial plateau fracture (MTPF) after medial unicompartmental knee arthroplasty (UKA) is a rare but significant complication. Materials and methods. MEDLINE, ScienceDirect and Cochrane Library databases were searched using specific search terms. The inclusion criteria were articles in English, medial unicompartmental knee arthroplasty intraoperative or stress MTPF, reported patients’ demographics and fracture characteristics, the treatment process, any case with a follow-up for a minimum of 3 months and the reported outcome. The exclusion criteria were lateral tibial plateau fracture, traumatic injury, all cases with a follow-up shorter than 3 months and no reported outcome. Results. From 374 records initially found, 36 were included in the analysis highlighting the characteristics, causes and mechanisms of UKA-related MTPF. As to the treatment outcomes, only 10 studies with a total of 19 cases met our inclusion and exclusion criteria. What was also reported was a case report of a 52-year-old patient diagnosed with MTPF one week after UKA and treated using ORIF with support plate and bone augmentation. At the 8-month follow-up, the patient was complaint-free and received 88 points in the KOOS Score. Conclusions. Several measures were proposed in the literature to minimize the risk of UKA-related MTPF. One of them is appropriate patient selection (BMI, BMD). As to the operative technique, positioning tibial pins too close to the medial tibial cortex and tibial plateau, extending the sagittal and vertical cut, damaging the posterior cortex and using excessive force during hammering should be avoided. In addition, the proper tibial component size and placement (considering the gender, race and knee alignment) is also important. UKA-related MTPF was reported to be managed with either conservative treatment, ORIF or revision to total knee arthroplasty (TKA). While conservative treatment carries a high risk of failure, and the revision to TKA is a massive procedure associated with the removal of all UKA components, ORIF was reported to bring favorable outcomes, being less invasive than revision to TKA.

Medial peg position of cementless porous tantalum tibial component affects bone mineral density around the prosthesis after total knee arthroplasty: 2-year follow-up study

BackgroundUse of a porous tantalum tibial component for total knee arthroplasty (TKA) was reported to have beneficial effects on periprosthetic bone mineral density (BMD). In some cases, hexagonal peg is placed close to or in contact with the tibial cortex, which may result in stress-shielding around the peg. However, no studies have analyzed the relationship between peg position and BMD. The aim of this study was to compare the peg position and BMD around the peg in a porous tantalum tibial component after TKA. MethodsTwenty-seven patients (27 knees) who underwent primary TKA with a cementless porous tantalum tibial component were investigated. BMD was measured by dual-energy X-ray absorptiometry for 2 years after the operation. The distance between the peg and the tibial cortex (peg distance) was measured on the medial and lateral sides. ResultsBMD was decreased in the medial region after the operation (p < 0.01). Relative change in BMD was lower in the medial region than in the central and lateral regions (p < 0.01). Multiple regression analysis showed that medial peg distance was negatively correlated with relative change of BMD in the medial part of the tibia (p = 0.04, R = 0.402). ConclusionsThe medial peg position affected the postoperative relative change of BMD in the medial part of the tibia, but did not affect the longevity of the implant. As the tibial medial peg became closer to the medial tibial cortex, the BMD loss became larger in the medial part of the tibia at 2 years postoperatively.

Short distance from the keel to the posterior tibial cortex is associated with fracture after cementless Oxford UKA in Asian patients.

Tibial plateau fractures are serious complications of Oxford mobile-bearing unicompartmental knee arthroplasty (OUKA). This study examined where the fracture lines arises and evaluated the keel-cortex distances (KCDs) using three-dimensional computed tomography (3D-CT) and the effects of technical error (assessed by tibial component positions) and proximal tibial morphology on the KCDs. This retrospective study included 217 OUKAs with cementless tibial components. Fifteen patients had tibial fractures after surgery. Anterior and posterior KCDs and fracture line origins were assessed using 3D-CT postoperatively. Proximal tibial morphology was assessed using the medial eminence line (MEL), which runs parallel to the tibial axis and passes through the tip of the medial intercondylar eminence of the tibia on long-leg anteroposterior radiograph. Knees had overhanging medial tibial condyle if the MEL passed medially to the medial tibial cortex. KCDs were compared between patients with/without fractures. Tibial component positions were evaluated, considering effects of tibial morphologies and component positions on fracture prevalence and KCDs. Fracture lines were found between the keel and posterior cortex in 12/15 patients. Posterior KCDs were significantly shorter in patients with fractures than in patients without (2.7 ± 1.6mm vs 5.2 ± 1.7mm, P < 0.001). Patients with medial overhanging condyles were more likely to have fracture (10/51 vs 5/166, P < 0.001) and had significantly shorter posterior KCD than those without (3.6 ± 1.5mm vs 5.5 ± 1.8mm, P < 0.001). Patients with tibial component that was set too medial, low, and valgus had higher rates of fracture than those without (7/39 vs 8/178, P = 0.008). Medial (r = 0.30, P < 0.001), low (r = -0.33, P < 0.001), and valgus implantations (r = 0.35, P < 0.001) of tibial components were related to shorter posterior KCDs. Short posterior KCD after OUKA is a risk factor for postoperative tibial fracture. Patients with either malposition of the tibial component (too medial, low, and valgus) and/or a medial overhanging condyle exhibit a shorter distance of posterior KCD and higher rate of fracture. Level III.

Tibial cutting guide (resector) holding pins position and subsequent risks of periprosthetic fracture in unicompartmental knee arthroplasty: a finite element analysis study

BackgroundPeriprosthetic fracture of the tibia after unicompartmental knee arthroplasty has been reported to be associated with excessive pin holes created for stabilization of the cutting guide. However, fractures have also been reported in cases using two pins as in the method suggested by the manufacturer. It is currently unclear whether variations in pinhole positions make a difference in proximal tibial fracture risk.MethodsFinite element models were constructed using Chinese female bone computed tomography images, with bone cuts made according to the surgical steps of implanting a fixed bearing unicompartmental arthroplasty. Four combinations of pinholes (pins placed more closely to the medial tibial cortex or centrally along the mechanical axis as allowed by the tibial cutting guide) created for tibial cutting guide placement were tested by finite element analyses. Testing loads were applied for simulating standing postures. The maximum von Mises stress on the tibial plateau was evaluated.ResultsPinhole placed close to the medial edge of the proximal tibial plateau is associated with the highest stress (27.67 Mpa) and is more likely to result in medial tibial fracture. On the contrary, pinhole placed along the central axis near the tibial tuberosity has the lowest stress (1.71 Mpa) and reflects lower risk of fracture.ConclusionThe present study revealed that placing tibial cutting guide holding pins centrally would lower the risks of periprosthetic fracture of the medial tibial plateau by analyzing the associated stress in various pin hole positions using finite element analysis.

Undercorrection: the undesired effect of compression on the osteotomy gap of the medial opening wedge high tibial osteotomy and its clinical significance.

Undercorrection is a common problem in opening wedge high tibial osteotomy (OWHTO). We investigated the compression effect of cortex screw on the osteotomy gap and its clinical significance. A standard OWHTO using the TomoFix plate was conducted on 20 bone models in two groups to get a 10-mm medial osteotomy gap. A cortex screw was used temporarily in a neutral (at the center) and an eccentric position (near the inclined plane) of the dynamic hole in group 1 and group 2, respectively. The mean of undercorrection observed in the two groups was compared using an independent t test. Also, the effect of compression on the gap between the plate and medial tibial cortex, and the osteotomy gap was evaluated using a Sine rule. Besides, the mean undercorrection observed was assessed for clinical significance based on the effect on the weight-bearing axis (WBA) using a Cosine Rule. The mean undercorrection was 1.3 ± 0.6mm and 2.6 ± 0.6mm in group 1 and group 2, respectively. A significantly greater undercorrection was observed in group 2 (p < 0.001). The correction loss in group 2 has resulted from combinations of the sliding effect of the dynamic hole and oblique compression effect over the gap between the plate and medial tibial cortex whereas in group 1 it has only resulted from the oblique compression effect. The observed undercorrection in group 2 has resulted in clinically significant WBA shift (10%) over the width of the tibial plateau. In OWHTO, compression is important for the stability and healing of osteotomy, but it can also cause loss of correction. In patients requiring large correction, the surgeon should control the amount of compression required and consider making extra osteotomy gap to avoid undercorrection. Furthermore, the placement of cortex screws in neutral is essential to lower the risk of undercorrection.

The Trans-Syndesmotic Axis in Relation to the Distal Anterior Medial Tibial Cortex

Category:AnkleIntroduction/Purpose:Gardner et al. (2006) reported that over 50% of operative syndesmoses are malreduced. The functional consequence of syndesmotic malreduction at two years was reported in 2012. Miller et al. in 2013, found that the 15° and 30°clamp positions caused fibula external rotation and over compression of the syndesmosis joint. The 0° medial clamp position which was in line with the trans-syndesmotic axis (TSA) did not negatively impact fibular reduction as did the other two posterior clamp positions. The purpose of this study is to identify the medial exit point of the TSA on the tibia. We hypothesized that the TSA on the medial side of the ankle would be a constant distance from the medial anterior tibial cortex.Methods:Fifty consecutive CT scans of uninjured ankles were reviewed from our image archive system. On an axial 2- dimensional reformatted image proximal to the ankle joint that included the entire incisura a line was drawn connecting the anterior and posterior limits of the incisura of the tibia. A second line was then drawn at 90 degrees at the midpoint of the first line and extended medially.Results:The average distance of the medial TSA exit point from the anterior edge of the distal medial tibia was 2.9 mm (Range 0- 9 mm, standard deviation 2.03 mm). The average anterior to posterior length of the medial distal tibia was 23.6 mm (Range 16-30, standard deviation 3.01 mm).Conclusion:Syndesmosis reduction clamp placement may first involve identifying the TSA based upon the anterior edge of the distal medial tibia. This region may be used to locate the TSA for optimal medial clamp placement. This study provides a foundation for future clamp placement investigations.

Potential risk of medial cortex perforation due to peg position of morphometric tibial component in unicompartmental knee arthroplasty: a computer simulation study.

The purpose of this study is to evaluate the risk of medial tibial cortical perforation in unicompartmental knee arthroplasty (UKA) due to peg positions on the tibial tray of the Persona Partial Knee (PPK). Preoperative CT images of 60 patients and 60 osteoarthritic knees (30 male and 30 female patients) were used. A tibial multiplanar reconstruction (MPR) image was reconstructed in preoperative planning software, and the implant was placed in a virtual osteotomy plane. In addition to PPK, Zimmer Unicompartmental Knee (ZUK) and TRIBRID (TBD) were used for evaluation. The horizontal distances from the medial tibial cortex to the anterior and posterior pegs (APCD/PPCD, respectively) were measured under neutral, 3-degree varus, 3-degree valgus and 2mm distal positions. The differences between implants under the same positions and between positions using the same implants were compared. The percentage of total cases with APCD/PPCD of less than 3mm and the perforation risk rate were calculated. The APCD of PPK was significantly shorter at all positions except for the varus position of TBD. The PPCD of PPK was significantly shorter at all positions compared to ZUK and TBD. There were no cases with an APCD of less than 3mm. Except for varus positions, the perforation risk rate of PPCD was significantly higher for PPK than the other two implants. The posterior pegs of the PPK are located more medially than the other two implants, which may result in perforation of the medial tibial cortex during implantation. Surgeons should consider the risk involved in the type of implant used.

Various Types of Medial Tibial Bone Resorption after Total Knee Arthroplasty Using a Thick Cobalt Chromium Tibial Baseplate.

Recent literature has implicated a thick cobalt chromium baseplate as a potential source of stress shielding and medial tibial bone resorption after total knee arthroplasty (TKA) in a Western population. The purpose was to calculate the incidence of various types and severity of medial tibial bone resorption utilizing a novel classification system after TKA with a thick cobalt chromium baseplate in Asian patients. Five hundred TKAs using Attune prostheses with mean follow-up of 3.4 years were evaluated, using the prospective radiographic data. The mean age was 71.3 years. The preoperative mechanical axis was varus, 11.2 degrees. The type and severity of medial tibial bone resorption were categorized as type U (resorption under the tibial baseplate up to 50% [U1] or beyond 50% [U2] of medial tibial tray width), C (resorption around the penetrated cement under the baseplate), and M (resorption on the medial tibial cortex without extension to the baseplate). Bone resorption of medial proximal tibia was observed in 96 knees (19.2%). Types U1 and U2 were seen in 46 and 28 knees, respectively. Type C was observed in 12 knees and type M in 10 knees. The type U resorption group had significantly more preoperative varus deformity (varus 12.9 vs. 10.9 degrees, p = 0.017). Medial tibial bone resorption after TKAs using a thick cobalt chromium baseplate is not uncommon and has various locations, types, and severities. The medial tibial bone resorption might be related to various causes, including stress shielding, thermal necrosis from cement in the bony hole, and bony devascularization. The type-U resorption has to be closely observed in patients with preoperative severe varus deformity. This is a Level IV study.

Tibial shape and size predicts the risk of tibial plateau fracture after cementless unicompartmental knee arthroplasty in Japanese patients.

Cementless unicompartmental knee arthroplasty (UKA) has advantages over cemented UKA, including improved fixation, but has a higher risk of tibial plateau fracture, particularly in Japanese patients. The aim of this multicentre study was to determine when cementless tibial components could safely be used in Japanese patients based on the size and shape of the tibia. The study involved 212 cementless Oxford UKAs which were undertaken in 174 patients in six hospitals. The medial eminence line (MEL), which is a line parallel to the tibial axis passing through the tip of medial intercondylar eminence, was drawn on preoperative radiographs. Knees were classified as having a very overhanging medial tibial condyle if this line passed medial to the medial tibial cortex. They were also classified as very small if a size A/AA tibial component was used. The overall rate of fracture was 8% (17 out of 212 knees). The rate was higher in knees with very overhanging condyles (Odds ratio (OR) 13; p < 0.001) and with very small components (OR 7; p < 0.001). The OR was 21 (p < 0.001) in those with both very overhanging condyles and very small components. In all, 69% of knees (147) had neither very overhanging nor very small components, and the fracture rate in these patients was 1.4% (2 out of 147 knees). Males had a significantly reduced risk of fracture (OR 0.13; p = 0.002), probably because no males required very small components and females were more likely to have very overhanging condyles (OR 3; p = 0.013). 31% of knees (66) were in males and in these the rate of fracture was 1.5% (1 out of 66 knees). The rate of tibial plateau fracture in Japanese patients undergoing cementless UKA is high. We recommend that cemented tibial fixation should be used in Japanese patients who require very small components or have very overhanging condyles, as identified from preoperative radiographs. In the remaining 69% of knees cementless fixation can be used. This approach should result in a low rate of fracture. Cite this article: Bone Joint J 2020;102-B(7):861-867.

A Novel Technique for Varus Tibial Cutting for Oxford Unicompartmental Knee Arthroplasty.

To reduce the stress on the medial tibial cortex and to decrease the risk of fracture, a varus cut of the tibia appears to be a reasonable alternative to the orthogonal cut by conventional methods. We present a new instrument and procedure, which enables a varus tibial cut for Oxford unicompartmental knee arthroplasty. We used a custom-made, slidable fixator instead of the standard fixator to set the extramedullary rod on the leg. We also made a numeric formula and a chart to arrange the varus cutting angle using the length of the mediolateral shift of the distal end and the longitudinal extension length of the extramedullary tibial rod. A varus cut up to 4.5° can be controlled. This technique is a simple and useful means of obtaining a varus tibial cut for Oxford unicompartmental knee arthroplasty.

Anatomic Risk to the Neurovascular Structures With a Medially Based All-Inside Syndesmosis Suture Button Technique

Recent evidence suggests that the use of suture button devices for ankle syndesmosis fixation is increasing. Multiple studies have shown some concern about damaging the greater saphenous neurovasculature with placement of the anchor point on the medial tibial cortex. We hypothesized that an all-inside button deployment technique would allow for a low risk to medial soft tissue structures. A total of 40 syndesmosis suture buttons were placed into 10 separate cadaveric lower limbs, using the newly developed technique. Four suture buttons were sequentially placed from distal to proximal in each limb within the zone of typical syndesmosis fixation, using fluoroscopic guidance. A medial incision was then performed to evaluate the relationship of the suture buttons to the medial soft tissue structures and the medial malleolus. Thirteen of 40 suture buttons (32.5%) were placed anterior, 7 (17.5%) posterior, and 20 (50%) with a portion of the button directly deep to the saphenous vein. Two of 40 buttons (5%) were placed within the tibial periosteum, and 38 (95%) were subfascial and directly superficial to the periosteum. Four of 40 (10%) limbs revealed a perforation in the saphenous vein from the guidepin. In conclusion, risks to the medial neurovascular structures exist with the medial deployment technique, but they appear to be mitigated compared with previous publications. The necessity of a medial incision to evaluate for soft tissue entrapment may not be necessary in all patients, as this technique appears to be safe, accurate, and reproducible.

Fracture de la malléole médiale. Étude biomécanique des méthodes de fixation par cerclage métallique sous tension

BackgroundThis study compared the biomechanical properties of three different fixation methods of tension band wirings, used in the treatment of medial malleolus fractures. The first method used an innovative “handmade bent pin” for cerclage fixation. The second method used a U-shaped K-wire to attach the cerclage to the medial tibial cortex. These two novel fixation techniques were compared with the traditional tension band wiring technique, which is fixated to the bone by a screw. HypothesisNovel fixation techniques of tension band wiring provide stable fixation. Material and MethodsIn this study 27 artificial bone models, which medial malleolus fractures were simulated on, were used. Using an electromechanical test device, the force required to pull out each implant was assessed and compared. ResultsThis study found that; while handmade bent pinning resulted averagely 840.25 N (range: 647–1066,±118.72) and U-shaped K-wire fixation was 381.71 N (range: 176–651±150.2) pull out strength, traditional tension band wiring indicated 871.33 N (range: 549–1008,±137.74) pull out strength. DiscussionHandmade bent pinning method provides similar results with traditional tension band wiring. Therefore, in suitable cases, it may be an acceptable alternative to traditional tension band wiring techniques when treating malleolar fractures. Although the outcomes of U-shaped K wire fixation indicated lower than other two groups, the outcomes were comparable with the literature. So, while performing tension band wiring, both handmade fixation systems may be used in certain cases. For orthopaedic surgeons, it is better to know and think about these alternative handmade pinning systems created from simple K-wires during the surgery if needed. Level of evidenceIV, Biomechanical trial.

Terminal position of a tibial intramedullary nail: a computed tomography (CT) based study.

The purpose of this study is to characterize the distal anatomic end-point of a tibial intramedullary nail placed using modern surgical techniques. The goal is to improve reduction of distal tibia fractures. An intramedullary nail was placed in 14 skeletally mature legs. This included 8 patients with mid-shaft tibial fractures and 6 intact cadaveric legs. Each nail was a titanium cannulated tibial nail, size 10- or 11-mm. The nails were placed using a suprapatellar or transpatellar approach with an ideal starting point. All legs received post-nail insertion CT scans and fluoroscopy. The main outcome measure was the terminal location of the nail just proximal to the distal tibial physeal scar, as seen on axial CT and fluoroscopic views of the ankle (mortise and lateral). The end-point was measured as the (1) ratio of medial-lateral tibial width (ML ratio) and (2) ratio of anterior-posterior tibial width (AP ratio). Two-tailed Welch's t tests were used to compare the actual, observed position of the nail to the hypothesized center-center position (H0 = ML and AP ratio of 0.5). All enrolled patients (n = 8) and cadaveric legs were included (n = 6). On axial CT, the average distance from the medial tibial cortex to the nail center as a ratio of medial-lateral tibial width was 0.63, 95% CI 0.60-0.67, p < 0.001 (Patient = 0.60, 95% CI 0.55-0.64, p = 0.001) (Cadaver = 0.68, 95% CI 0.64-0.73, p < 0.001). On fluoroscopic mortise views, the distance from the medial cortex to the nail center as ratio of medial-lateral tibial width was 0.64, 95% CI 0.60-0.67, p < 0.001 (Patient = 0.61, 95% CI 0.56-0.65, p < 0.001) (Cadaver = 0.67, 95% CI 0.63-0.72, p < 0.001). The AP ratio was not significantly different from 0.5 on either axial CT or fluoroscopic mortise views (p > 0.05). The distal end-point of a tibial intramedullary nail is lateral (ML plane) and center (AP plane) in both cadaveric legs and patients with midshaft tibia fractures. These results suggest that the treatment of distal tibia fractures with intramedullary nails may be improved by positioning the nail slightly lateral in the distal segment. Diagnostic level I.

Medial malleolus fractures: A biomechanical comparison of tension band wiring fixation methods

BackgroundThis study compared the biomechanical properties of three different fixation methods of tension band wirings, used in the treatment of medial malleolus fractures. The first method used an innovative “handmade bent pin” for cerclage fixation. The second method used a U-shaped K-wire to attach the cerclage to the medial tibial cortex. These two novel fixation techniques were compared with the traditional tension band wiring technique which is fixated to the bone by a screw. HypothesisNovel fixation techniques of tension band wiring provide stable fixation. Material and methodsIn this study 27 artificial bone models, which medial malleolus fractures were simulated on, were used. Using an electromechanical test device, the force required to pull out each implant was assessed and compared. ResultsThis study found that; while handmade bent pinning resulted averagely 840.25N (range: 647–1066±118.72) and U-shaped K-wire fixation was 381.71N (range: 176–651±150.2) pull out strength, traditional tension band wiring indicated 871.33N (range: 549–1008±137.74) pull out strength. DiscussionHandmade bent pinning method provide similar results with traditional tension band wiring. Therefore, in suitable cases, it may be an acceptable alternative to traditional tension band wiring techniques when treating malleolar fractures. Although the outcomes of U-shaped K-wire fixation indicated lower than other two groups, the outcomes were comparable with the literature. So while performing tension band wiring, both handmade fixation systems may be used in certain cases. For Orthopaedic surgeons, it is better to know and think about these alternative handmade pinning systems created from simple K-wires during the surgery if needed. Level of evidenceIV, Biomechanical trial.

Clinical and Radiographic Outcomes of Tibiotalocalcaneal or Pantalar Arthrodesis Using a Novel Lateral Locking Plate

Category: Ankle Introduction/Purpose: For patients suffering from severe ankle and hindfoot arthritis or deformity, tibiotalocalcaneal (TTC) or pantalar arthrodesis may be the best option to achieve a plantigrade and painless foot. These fusions are typically fixed with a retrograde intramedullary nail, a lateral side plate, or screws alone. Theoretically, the advantages of a lateral side plate applied via a trans-fibular approach include the use and the multiple points of fixation available in the tibia, talus, and calcaneus. The results of a novel side plate construct with a unique screw hole that extends underneath the calcaneus are presented in this study. A large diameter screw can be inserted retrograde through this inferior hole to engage the medial tibial cortex and provide axial compression across the ankle and subtalar joints. Methods: This study retrospectively evaluated 39 patients that underwent a tibiotalocalcaneal (TTC) or pantalar arthrodesis using this novel lateral plate fixation technique by one of three fellowship trained surgeons at a tertiary referral center. Patients with less than a one year follow up were excluded. Thirty-nine patients were identified between 2012 and 2016. Two patients were deceased from other causes, 2 had a below the knee amputation due to chronic pain, and 9 were lost to follow up. Pre- and postoperative General Health and Wellness (SF-12) and Revised Foot Function Index scores were obtained. Study subjects were seen for a clinical evaluation and final post-operative x-rays. The Shapiro-Wilk test was used to test for normality. The paired student’s t-test was used to compare pre- and post-surgical outcome measures. Results: Twenty-six patients were included in the study group. Mean follow up time was 34.42 ± 12.94 months. The SF-12 score was 32.2 ± 10.22 (physical) and 54.8 ± 10.7 (mental) before surgery, and 41.35 ± 9.21 (p &lt; 0.01) and 56.5 ± 7.47 (p = 0.73) at final follow-up, respectively. The FFI score was 106 ± 32.69 before surgery and 53.94 ± 24.14 after surgery (p = 0.06). Eighteen patients were satisfied or very satisfied with the outcome of the surgery (70%). CT confirmation of joint fusion was obtained in all 26 patients. Twenty out of the 26 patients demonstrated fusion of all joints (77%). There were 2 ankle, 1 subtalar, and 1 talonavicular nonunions. In total, 44 of 48 total joints were fused (91%). Conclusion: Tibiotalocalcanceal and pantalar arthrodesis using a novel lateral plate for the treatment of complex deformity and severe osteoarthritis demonstrated acceptable fusion rates considering the number of patients with high risk factors for nonunion in this study group. Complications included fractures at the proximal end of the plate construct and persistent neurapraxia which was well tolerated. Patients reported significant improvements in SF-12 clinical scores at final 34 month follow-up.