Bone Cuts Research Articles

The severity of preoperative varus deformity affects the feasibility of correcting lower limb alignment with medial unicompartmental knee arthroplasty

BackgroundThe relationship between the severity of preoperative varus deformity and the amount of its correction in unicompartmental knee arthroplasty (UKA) as well as the thickness of the insert has not been well known. MethodsOne hundred and three patients who underwent medial fixed-bearing UKA with the use of the spacer block method were assessed. After the component gap in extension was measured using a UKA tensor, the pre-osteotomy gap was calculated from the thickness of the bone cuts. The relationship between the preoperative hip–knee–ankle (HKA) angle as well as the pre-osteotomy gap and the amount of change in HKA angle were analysed. Also, preoperative HKA angle and the thickness of the bone cuts were compared among groups by the insert thickness. ResultsThe mean preoperative HKA angle was 7.7 ± 3.1° varus. Patients with more varus deformity and those with a wider pre-osteotomy gap showed a more valgus change in HKA angle. As for the thickness of the insert, the preoperative HKA angle of the patients with the thinnest insert was significantly smaller (less varus) than that of those with the thicker insert while no statistically significant difference was found among the insert groups regarding the amount of the bone cuts. ConclusionsThe severity of the preoperative varus deformity as well as the intraoperative pre-osteotomy gap related to the amount of change in HKA angle. As thick inserts tended to be used in severe varus knees, the tibial bone cut can be reduced in such cases.

What are the perceived benefits and barriers to the use of robot-assisted total knee arthroplasty? A survey of members of the European Knee Society.

Members of the European Knee Society (EKS) recently took part in an online questionnaire on robot-assisted TKA. The purpose of this study was to report and analyse the questionnaire results on the demographics of users versus non-users, the drivers for users of the technology, and the barriers or limitations that hinder the uptake ofrobot-assisted TKA. The questionnaire was composed of 16 questions covering surgeon demographics and drivers for or barriers to the use of robotics. Responses on four- or five-point Likert scales were trichotomised depending on the type of question ("not important" - "moderately important" - "important/very important" or "fully disagree/disagree" - "neutral" - "agree/fully agree"). Consensus on a statement was defined as at least 75% agreement. There was a 67% response rate. Forty-five surgeons performed conventional TKA, of which 78% aimed for systematic alignment, while22 performed robot-assisted TKA, of which 82% aimed for individualised alignment, and 16 performed technology-assisted TKA, of which 56% aimed for systematic alignment. Respondents agreed that robotics significantly impact accuracy of bone cuts (51/62, 82%), intra-operative feedback on ligament balancing (56/62, 90%) as well as bone cut orientation and implant positioning (57/ 62, 92%), and assistance to customise alignment (56/62, 90%). Respondents agreed that associated costs (14/18, 78%) are an important aspect fornotusing or to stop using robotics. The majority of respondents still perform conventional TKA (54%), while only a small portion perform robot-assisted TKA (27%) or other technology-assisted TKA (19%). Most robot users aim for individualised lower limb alignment, whereas most other surgeons aimed for systematic lower limb alignment. There is consensus that robotic assistance has a positive impact on accuracy of bone cuts and alignment, but no consensus on its impact on other peri- or post-operative outcomes. Finally, the associated cost of robot-assisted TKA remains the main barrier to its uptake. V.

The impact of different alignment strategies on bone cuts for neutral knee phenotypes in total knee arthroplasty

PurposeThe purpose of this study was to simulate and visualise the influence of the alignment strategy on bone resection in neutral knee phenotypes. It was hypothesised that different amounts of bone resection would be required depending on the alignment strategy chosen. The hypothesis was that by visualising the corresponding bone cuts, it would be possible to assess which of the different alignment strategies required the least change to the soft tissues for the chosen phenotype but still ensured acceptable component alignment and could, therefore, be considered the most ideal alignment strategy.MethodsSimulations of the different alignment strategies (mechanical, anatomical, restricted kinematic and unrestricted kinematic) regarding their bone resections were performed on four common exemplary neutral knee phenotypes. NEUHKA0° VARFMA 90° VALTMA90°, NEUHKA0° NEUFMA 93° NEUTMA87°, NEUHKA0° VALFMA 96° NEUTMA87° and NEUHKA0° VALFMA 99° VARTMA84°. The phenotype system used categorises knees based on overall limb alignment (i.e. hip knee angle) but also considers joint line obliquity (i.e. TKA and FMA) and has been used globally since its introduction in 2019. These simulations are based on long leg weightbearing radiographs. It is assumed that a change of 1° in the alignment of the joint line corresponds to correspond to 1 mm of distal condyle offset.ResultsIn the most common neutral phenotype NEUHKA0° NEUFMA 93° NEUTMA87°, with a prevalence of 30%, bone cuts remain below 4 mm regardless of alignment strategy. The greatest changes in the obliquity of the joint line can be expected for the mechanical alignment of the phenotype NEUHKA0° VALFMA 99° VARTMA84° where the medial tibia is raised by 6 mm and the lateral femur is shifted distally by 9 mm. In contrast, the NEUHKA0° VARFMA 90° VALTMA90° phenotype requires no change in joint line obliquity if the mechanical alignment strategy is used.ConclusionIllustrations of alignment strategies help the treating surgeon to estimate the postoperative joint line obliquity. When considering the alignment strategy, it seems reasonable to prefer a strategy where the joint line obliquity is changed as little as possible. Although for the most common neutral knee phenotype the choice of alignment strategy seems to be of negligible importance, in general, even for neutral phenotypes, large differences in bone cuts can be observed depending on the choice of alignment strategy.

Translated article] Comparison of three different minimally invasive intramedullary screw for proximal phalanx fractures. A biomechanical study

Background and objectivePhalangeal fractures are the most common hand fractures. In the last years, intramedullary compression screw (IMHCS) for instable transverse or short oblique proximal P1 fractures have been described. Although both anterograde (intraarticular or trans-articular) and retrograde IMHCS techniques have shown good results, no comparison between anterograde and retrograde screw in P1 fractures has been published. We sought to determine stability with retrograde IMHCS and anterograde IMHCS, both trans-articular and intra-articular technique, in a cadaveric transverse proximal P1 fracture model, at two different levels. Material and methodsWe performed a biomechanical study in 30 fresh-frozen human cadaveric P1 fracture model. Fracture was performed at 9-mm from the metacarpo-phalangeal (MCP) joint in 15 specimens, whereas it was done at 15mm in the other 15. In turn, in each group, five fractures were stabilised with an anterograde intra-articular IMHCS, five with anterograde trans-articular IMHCS and other five with retrograde IMHCS. ResultsAnterograde IMHCS fixation in 9-mm P1 fractures (both trans- and intra-articular technique, 62.74N and 70.86N, respectively) was found to be more stable than retrograde IMHCS one (32.72N) (p=0.022). Otherwise, retrograde IMHCS fixation was found to be more stable in more distal P1 fractures (90.52N retrograde vs. 57.64N trans-articular vs. 42.92N intra-articular; p=0.20). ConclusionsAnterograde IMHCS fixation in proximal transverse P1 bone cut in a cadaveric model provides more stability than retrograde IMHCS, while retrograde screw provides more stability when the bone cut is located more distal.

Pyrocarbon Disc Interposition Arthroplasty (PyroDisk) for the Treatment of Carpometacarpal Thumb Joint Osteoarthritis.

Preoperatively, review radiology images to confirm that the osteoarthritis is limited to the thumb CMC joint and that all appropriate tools for inserting the disc are available before beginning surgery. Next, the patient is placed with their arm on an arm rest. The CMC thumb joint is exposed via a dorsal longitudinal skin incision, sparing the dorsal radial nerve branches and the radial artery and accompanying venes. The capsule is opened with an H-incision. With 2 parallel cuts to the joint surface, the articular surfaces of the joint are removed. After resection of the articular joint surfaces, the residual width and height of the joint space after resection are measured. The central point in the joint surfaces is marked for the bone tunnels. With an awl, tunnels are created from the center of the joint surface to the proximal (trapezial bone) and distal (first metacarpal bone) and the dorsal side. The implant size is measured with the trial implants for correct size of the disc. A tendon strip of either APL (abductor pollicis longus) or FCR (flexor carpi radialis) tendon is harvested for use securing the disc. The disc is secured with the tendon strip from proximal through the trapezium, through the disc and distal through the first metacarpal, and is secured to itself at the trapezial bone. The position is checked under fluoroscopy. When the disc in the right position, the joint capsule and skin are closed and a plaster cast is applied with the thumb in abduction. Alternative treatments include hemitrapeziectomy without interposition; full trapeziectomy, with or without ligament reconstruction and/or tendon interposition; and joint resurfacing prostheses. The advantage of pyrocarbon disc interposition arthroplasty over other treatment options is the preservation of the STT joint1. Therefore, the procedure is minimally harming the surrounding anatomy despite open surgery and has a high success rate in reducing pain while preserving function and strength. The risk of complications is comparable with that of other CMC joint arthroplasty techniques. A relatively high survival rate has been reported at a mean follow-up of 7 years (range, 5 to 12 years). In cases of recurrent pain, all other surgical options remain possible ("no bridges are burned"). The main disadvantage is the cost of the disc. Our recent study of this technique showed good patient-reported outcomes, pain reduction, patient satisfaction, and preservation of strength and range of motion at a mean follow-up of 7 years1,2. The survival rate was 91%, with 3% failing as a result of disc dislocation. Other reasons of failure were STT osteoarthritis and pain without a specific cause. Preoperatively, make sure that only the CMC thumb joint has osteoarthritis and that the STT joint does not. In cases in which it is unclear whether the osteoarthritis is isolated to the CMC thumb joint, perform computed tomography to make certain10.Only a few millimeters of bone must be resected from the first metacarpal base and the distal trapezium. Both bone cuts must be made parallel to each other and perpendicular to the longitudinal axis of the first metacarpal bone.Bone tunnels must be exactly centered in the cut joint surfaces for proper implant positioning and to decrease the chance of subluxation.Size the implant properly and check movement and stability. OR = operating roomFCR = flexor carpi radialisAPL = abductor pollicis longusPRWHE = Patient-Rated Wrist and Hand EvaluationDASH = Disabilities of the Arm, Shoulder and Hand QuestionnaireMHQ = Michigan Hand QuestionnaireROM = range of motionFU = follow-upCRPS = complex regional pain syndromeLRTI = ligament reconstruction and tendon interpositionMRI = magnetic resonance imagingCT = computed tomography.

An Unusual Case of Tongue Entrapment in a Plastic Water Bottle

Background: Foreign bodies inside the oral cavity are commonly encountered among children. One peculiar occurrence is when the tongue gets entrapped in foreign bodies such as bottles. This happens as children often insert their tongues into the bottle and apply oral suction to ingest the last few drops from the bottle. There is a paucity of data in Indian literature and no recommended guidelines for the management of such cases. Clinical Description: The patient, a 12-year-old boy had a history of inability to remove a plastic water bottle sipper from around the tongue while swallowing water quickly. He was initially asymptomatic and then he started developing progressive pain and swelling on the anterior part of the tongue. On examination, the plastic sipper was constricting the tongue circumferentially and the patient felt a sharp pain on maneuvering the bottle. Minimal discoloration of the anterior part of the tongue had set in 1 h after the presentation. Management: Lubrication with 2% lignocaine jelly and ice packs circumferentially followed by attempts of gentle traction and manipulation to remove the foreign body were unsuccessful. Consequently, the patient was shifted to the emergency operation theater where the patient was sedated with intravenous (IV) ketamine and midazolam after securing a nasopharyngeal airway with 100% preoxygenation. An orthopedic bone cutter was used, and a radial cut was given on the impacted end of the bottle, and the constricted part was removed as pressure on the tongue was released, followed by 100% oxygenation with bag and mask ventilation. Conclusion: Immediate intervention in cases of the entrapped tongue can prevent grave consequences such as airway compromise and tongue ischemia and necrosis. Mechanical removal can be done safely using heavy scissors or orthopedic bone under IV sedation after securing the airway in collaboration with the anesthesia team.

Can mobile-bearing unicompartmental knee arthroplasty achieve natural gap-balancing? An observational study with a novel pressure sensor

BackgroundMobile-bearing unicompartmental knee arthroplasty (MB-UKA) is an effective treatment for anteromedial knee osteoarthritis. Meticulous intraoperative soft tissue balancing remains challenging yet consequential for a successful operation. Currently, surgeons rely mostly on their experience during soft tissue balancing, yielding unreproducible results. The purpose of this study was to quantified measure the soft tissue tension of medial compartment and determine if an optimal "target" tension values with the natural state exists.MethodsThis was an observational study of 24 consecutive patients. All 30 UKAs were performed by a single surgeon. The piezoresistive sensor was custom designed to fit in the medial compartment gap. Contact pressures were measured at 5 angular positions of the knee intraoperatively: 0°, 20°, 45°, 90°, and 110° of flexion. The change in pressure from extension (20° position) and flexion (110° position) was also calculated (E-FPD). Data on age, sex, body mass index, operative side, and bearing size were collected. Outcome measures were measured at baseline and at the 6-month postoperative follow-up; Oxford Knee Score, visual analog scale score, and range of motion were compared to evaluate clinical outcomes.ResultsThere was a significant improvement in patients in all measured outcomes at 6 months from baseline (P < 0.05). The E-FPD of 14.9 N (8.9, 24.6) was indicative of appropriate soft tissue balancing throughout the functional range of knee motion. Of 30 knees, 22 were 3-mm bearing and 8 were 4- or 5-mm bearing. The pressure data of the 3-mm bearing group was larger than that of the non-3-mm bearing group for each knee flexion degree, but the difference was not statistically significant (P > 0.05).ConclusionsObjective data from sensor output may assist surgeons in decreasing loading variability during MB-UKA. The data suggested that MB-UKA could not accurately restore soft tissue tension to the natural state, which was related to the inability of MB-UKA surgical instruments to fine adjust the bone cut and soft tissue release.Study registrationChinese Clinical Trial Registry (http://www.chictr.org.cn): ChiCTR1900024146.

Kinematic Alignment Bi-unicompartmental Knee Arthroplasty With Oxford Partial Knees: A Technical Note.

Bi-unicompartmental knee arthroplasty (BiUKA) is an alternative to total knee arthroplasty for selected patients. Although it is thought to be technically demanding, the technique has not been previously described in detail. Kinematic alignment (KA) implantation and bone cuts parallel to the native joint line would be beneficial to ensure optimal mechanical loading. Here, we detail a technique for KA-BiUKA using the Oxford partial knees. The joint line is identified using the spoon of the microplasty instrumentation system with/without the accessory spoons. The tibia is cut parallel with the joint line using a side-slidable ankle yoke so that the inclination of the cutting block is parallel with the spoon surface. After defining the horizontal bone-cutting lines, the predominantly affected condyle is operated upon, followed by the lesser affected condyle. Although custom-made devices are required, the technique is useful and reproducible in the performance of KA-BiUKA with the Oxford partial knees.

Functional outcomes in patient specific instrumentation vs. conventional instrumentation for total knee arthroplasty; a systematic review and meta-analysis of prospective studies

BackgroundTotal Knee Arthroplasty (TKA) is an established surgical option for knee osteoarthritis (OA). There are varying perceptions of the most suitable surgical technique for making bone cuts in TKA. Conventional Instrumentation (CI) uses generic cutting guides (extra- and intra-medullary) for TKA; however, patient specific instrumentation (PSI) has become a popular alternative amongst surgeons.MethodsA literature search of electronic databases Embase, Medline and registry platform portals was conducted on the 16th May 2021. The search was performed using a predesigned search strategy. Eligible studies were critically appraised for methodological quality. The primary outcome measure was Knee Society Function Score. Functional scores were also collected for the secondary outcome measures: Oxford Knee Score (OKS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), Knee Injury and Osteoarthritis Outcome Score (KOOS) and Visual Analog Scale (VAS) for pain. Review Manager 5.3 was used for all data synthesis and analysis.ResultsThere is no conclusive evidence in the literature to suggest that PSI or CI instrumentation is better for functional outcomes. 23 studies were identified for inclusion in this study. Twenty-two studies (18 randomised controlled trials and 4 prospective studies) were included in the meta analysis, with a total of 2277 total knee arthroplasties. There were 1154 PSI TKA and 1123 CI TKA. The majority of outcomes at 3-months, 6-months and 12 show no statistical difference. There was statistical significance at 24 months in favour of PSI group for KSS function (mean difference 4.36, 95% confidence interval 1.83–6.89). The mean difference did not exceed the MCID of 6.4. KSS knee scores demonstrated statistical significance at 24 months (mean difference 2.37, 95% confidence interval (CI) 0.42—4.31), with a MCID of 5.9. WOMAC scores were found to be statistically significant favouring PSI group at 12 months (mean difference -3.47, 95% confidence interval (CI) -6.57- -0.36) and 24 months (mean difference -0.65, 95% confidence interval (CI) -1.28—-0.03), with high level of bias noted in the studies and a MCID of 10.ConclusionsThis meta-analysis of level 1 and level 2 evidence shows there is no clinical difference when comparing PSI and CI KSS function scores for TKA at definitive post operative time points (3 months, 6 months, 12 months and 24 months). Within the secondary outcomes for this study, there was no clinical difference between PSI and CI for TKA. Although there was no clinical difference between PSI and CI for TKA, there was statistical significance noted at 24 months in favour of PSI compared to CI for TKA when considering KSS function, KSS knee scores and WOMAC scores. Studies included in this meta-analysis were of limited cohort size and prospective studies were prone to methodological bias. The current literature is limited and insufficiently robust to make explicit conclusions and therefore further high-powered robust RCTs are required at specific time points.

Orthodontic tooth movement with and without corticotomy – A study realized on animal model

Orthodontic treatment of dento-maxillary anomalies is a common therapeutic intervention, with a growing number of pediatric and adult patients requiring it [1]. The raising understanding of the need for this treatment option has led to a shift in the addressability of various social groups, leading to an increase in adult patients' interest [2]. Orthodontic treatment in adult patient is more dificult because the bone remodeling is hard to do and thereis not growing process. Cortiotomy consists of milling the alveolar bone, the vestibular board, in order to create small labor in which the dental displacement following the application of orthodontic force will be faster. The corticotomy is performed in local anesthesia, with bone cutters, under continuous cooling with saline. Orthodontic treatment in adult patient is more difficult because the bone remodeling is hard to do and thereis not growing process [3]. Filho et al. said that the introduction of this technique of corticotomy makes it possible to solve complex cases while providing an alternative to the classical approach, eliminating a number of inventients, such as dental extractions [4]. Despite the many benefits it can bring when it is integrated into orthodontic therapy to correct various dento-maxillary changes, the corticotomy is still regarded with some reluctance by orthodontists. Reitan et al. (2015) consider that the main reason is that the intervention is expensive and some consider it invasive [5]. In a similar study, Bos et al. (2005) points out that even for patients, the high costs of such an intervention can lead to its refusal, with the risk of obtaining results at the end of less satisfactory orthodontic treatment [1]. Dab et al. (2007) states that there is a direct link between the degree of dental displacement induced by the corticotomy and the type of dento-maxillary anomaly that needs to be corrected, but also the time of orthodontic treatment in which the surgery is performed [6]. Further experimental studies are also needed to understand in more detail the biological mechanisms and transformations that occur at the intervention level.

Comparación de tres técnicas de tornillo endomedular mínimamente invasivo para fracturas de falange proximal. Estudio biomecánico

Background and objectivePhalangeal fractures are the most common hand fractures. In the last years, intramedullary compression screw (IMHCS) for instable transverse or short oblique proximal P1 fractures have been described. Although both anterograde (intraarticular or trans-articular) and retrograde IMHCS techniques have shown good results, no comparison between anterograde and retrograde screw in P1 fractures has been published. We sought to determine stability with retrograde IMHCS and anterograde IMHCS, both trans-articular and intra-articular technique, in a cadaveric transverse proximal P1 fracture model, at two different levels. Material and methodsWe performed a biomechanical study in 30 fresh-frozen human cadaveric P1 fracture model. Fracture was performed at 9-mm from the metacarpo-phalangeal (MCP) joint in 15 specimens, whereas it was done at 15 mm in the other 15. In turn, in each group, five fractures were stabilized with an anterograde intra-articular IMHCS, five with anterograde trans-articular IMHCS and other five with retrograde IMHCS. ResultsAnterograde IMHCS fixation in 9-mm P1 fractures (both trans- and intra-articular technique, 62.74 N and 70.86 N, respectively) was found to be more stable than retrograde IMHCS one (32.72 N) (p = 0.022). Otherwise, retrograde IMHCS fixation was found to be more stable in more distal P1 fractures (90.52 N retrograde vs. 57.64 N trans-articular vs. 42.92 N intra-articular; p = 0.20). ConclusionsAnterograde IMHCS fixation in proximal transverse P1 bone cut in a cadaveric model provides more stability than retrograde IMHCS, while retrograde screw provides more stability when the bone cut is located more distal.

Navigated, gap-balanced, adjusted mechanical alignment achieves alignment and balancing goals in a very high percentage but with partially non-anatomical resections.

Navigated, gap-balanced adjusted mechanical alignment (AMA) including a 0° varus tibial cut and modification of angles and resections of the femoral cuts to obtain optimal balance accepting minor axis deviations. Objectives of this study were (1) to analyse to what extent AMA achieves the goals for leg alignment and gap balance, and (2) in what percentage non-anatomical cuts are needed to achieve these goals. Out of 1000 total knee arthroplasties (TKA) all varus knees (hip-knee-ankle (HKA) angle < 178°; n = 680) were included. All surgeries were performed as computer assisted surgery (CAS) in AMA technique. CAS data at the end of surgery were analysed with respect to HKA and gap-sizes. All bone cuts were quantified. Depending on the amount of deformity, a subgroup analysis was performed. It was analysed whether the amount of deformity influences the non-anatomical cuts by correlation analysis. AMA reached the goals for postoperative HKA (3° corridor) in 636 cases (93.5%). While extension and flexion gap balance were achieved in more than 653 cases (96%), flexion and extension gap size were equalled in 615 knees (90.4%). The resections of the lateral tibia plateau and distal and posterior medial femoral condyle were anatomical (Tibia: 7.0 ± 1.7mm; medial condyle distal: 7.8 ± 1.4mm; medial posterior: 8.2 ± 1.8mm). The number of non-anatomical resections for those cuts were low; 67 (9.9%); 24 (3.5%); 32 (4.7%). For the medial tibia plateau and the lateral posterior condyle, the cuts were non-anatomical in a high percentage of cases; Tibia: 606 (89.1%), lateral posterior condyle: 398 (58.5%). Moderate but significant correlations were found between resection differences and amount of deformity (medio-lateral: tibia: 0.399; distal femur: 0.310; posterior femur: 0.167). No correlations were found between resection differences and gap values. AMA reaches the intended target for HKA and gap balance in over 612 (90%) of cases and maintains the medial femoral condyle anatomically. Non-anatomical tibial resection causes increased external rotation of the femoral component and by that non-anatomical cut of the posterior lateral condyle. Nonanatomical resections of AMA might be one reason for the persisting high rate of unsatisfied patients after TKA. Anatomical and individual alignment philosophies might help to reduce this rate of dissatisfaction.

Novel Positioning Feedback System as a Guidance in Bone Tumor Resection.

Need: Bone resection using customized 3D-printed guides can improve accuracy, but the technique is still associated with clinically significant errors.Technical solution: We developed an inexpensive optical feedback system (OFS) that compares intraoperative 2D camera images to the pre-operative plan, and accurately depicts the surgeon's guide placement prior to cutting, reducing the errors in resection.Proof of concept: We simulated wide resections of a bone sarcoma on 24 cadaver femurs using 3 cutting guide types. Guide placement was measured using the OFS and compared to CT-scans showing the actual guide position. We carried out a second, controlled study on 20 sawbones, comparing the accuracy of the final bone cuts with and without the surgeon actively using the OFS to adjust the guide position before cutting.Results: For cadavers, in 2 of 3 planes, the position of the jig recorded by the OFS closely matched its actual position, with an accuracy of .87° ± .65°(r = .94) and 1.2° ± 1.3°(r = .81) in the transverse and sagittal planes, respectively. In the second study, OFS increased accuracy of the final cut about the transverse and sagittal planes, respectively by 53.1% (P = .011)/54.7% (P = .04) and 33% (P = .051)/38% (P = .042) in terms of rotation and translation.Next steps: Developing the OFS as a mobile application to reduce the processing time and improve accessibility in the operating room.Conclusion: The OFS could accurately depict the guide placement on the bone and significantly improve the surgical accuracy of 3D printed jigs.

Three-Dimensional Evaluation of Isodose Radiation Volumes in Cases of Severe Mandibular Osteoradionecrosis for the Prediction of Recurrence after Segmental Resection.

Background: Pre-operative margin planning for the segmental resection of affected bone in mandibular osteoradionecrosis (ORN) is difficult. The aim of this study was to identify a possible relation between the received RT dose, exposed bone volume and the progression of ORN after segmental mandibular resection. Method: Patients diagnosed with grade 3-4 ORN for which a segmental resection was performed were included in the study. Three-dimensional reconstructions of RT isodose volumes were fused with postoperative imaging. The primary outcome was the recurrence of ORN after segmental resection. Subsequently, RT exposed mandibular bone volumes were calculated and the location of the bone cuts relative to the isodose volumes were assessed. Results: Five out of thirty-three patients developed recurrent ORN after segmental mandibular resection. All cases with recurrent ORN were resected inside an isodose volume of ≥56 Gy. The absolute mandibular volume radiated with 56 Gy was significantly smaller in the recurrent group (10.9 mL vs. 30.7 mL, p = 0.006), as was the proportion of the mandible radiated with 56 Gy (23% vs. 45%, p = 0.013). Conclusion: The volume of radiated bone was not predictive for risk of progression. The finding that recurrent ORN occurred with bone resection margins within the 56 Gy isodose volume suggests that this could serve as a starting point for the pre-operative planning of reducing the risk of ORN recurrence.

Application of Ultrasonic Piezoelectric Technology for Rhinoplasty.

Application of Ultrasonic Piezoelectric Technology for Rhinoplasty.

Comparison of the Utilization of Tranexamic Acid and Tourniquet Use in Total Knee Arthroplasty: A Retrospective Case Series.

Introduction: Total knee arthroplasty (TKA) carries a high risk for significant blood loss due to bone cuts and extensive soft tissue involvement in the knee region. The use of tranexamic acid (TXA) or a tourniquet are two methods commonly employed to prevent significant blood loss and avoid the need for blood transfusion. TXA has been shown to reduce both intraoperative and postoperative bleeding as well as the probability that a patient will require a blood transfusion. The purpose of this study is to compare the efficacy of TXA and tourniquet use, both alone and in combination, in reducing blood loss during TKA.Methods: Data for this retrospective cohort study were obtained by searching records of patients who underwent TKA at a tertiary care center from January 2019 to October 2020. Data from 526 subjects were available. A chart review was conducted to determine if the patient received TXA only, tourniquet only, or both TXA and tourniquet during the TKA procedure. Primary outcomes for this study including procedure length in minutes, estimated blood loss in cubic centimeters, and total infusion pressor (phenylephrine) administered intraoperatively in milligrams were recorded for the study. Data were summarized using means and standard errors. Statistical methods used for analysis include one-way ANOVA, probability plots, the Shapiro-Wilk test for normality, the Kruskal-Wallis test, and Tukey’s test.Results: Data were available for 526 subjects. 122 subjects received tourniquet only (Tourniquet group), 104 received intravenous (IV) TXA only, 264 received both tourniquet and IV TXA (Tourniquet + TXA), and 36 received neither tourniquet nor TXA (None). The groups did not significantly differ in procedure length (p = 0.140) or infusion pressor total (p > 0.20). The groups did significantly differ in estimated blood loss (p < 0.001). Subjects who did not receive either TXA or tourniquet had significantly more blood loss than the Tourniquet and Tourniquet + TXA groups. Similarly, the TXA group had significantly more blood loss than both the Tourniquet and Tourniquet + TXA groups.Conclusion: This study supports the conclusion that the use of a tourniquet is superior to the use of TXA in reducing intraoperative blood loss during TKA. All groups that underwent TKA using a tourniquet, either alone or in combination with TXA, exhibited significantly lower levels of blood loss compared to the control (no intervention) group.

Enhanced Mid-Resection Workflow Technique for Severe Varus Deformity Correction Using Robotic-Arm Assisted Total Knee Arthroplasty

Introduction: Robotic technology in total knee arthroplasty has been proven to improve accuracy of component positioning, achieve alignment targets, and balance the knee objectively. However, the utility of robotics in correction of severe varus deformities of the knee has not been investigated in detail. The aim of this paper was to establish the utility and describe the technique of robotic-arm assisted total knee arthroplasty (RA-TKA) in achieving pre-balance in severe varus deformities of the knee. Materials and Methods: Among the existing Mako (Stryker, Kalamazoo, Michigan) RA-TKA workflows, pre-resection workflow is limited to knees which can be pre-balanced by component positioning according to functional alignment. Mid-resection workflow (distal femur/tibia first) is reserved for complex cases, whereby the extension gap is balanced first. In our experience, both workflows could not achieve pre-balance in severe varus deformities, necessitating the need to develop a novel technique. The ability of the robot to execute precise bone cuts allows for a provisional postero-medial femoral bone cut in flexion, giving access to remove large inaccessible posterior osteophytes and the tight posterior capsule, thus balancing the knee in extension. The flexion gap is subsequently matched to the extension gap by alterations in axial component positioning. Conclusion: This novel “enhanced mid-resection workflow” technique establishes the utility of the RA-TKA in balancing severe varus deformities of the knee. We also propose an algorithm which simplifies and helps surgeons choose between the three workflows to pre-balance knees irrespective of the severity of the varus deformity.

Current concept of kinematic alignment total knee arthroplasty and its derivatives.

The kinematic alignment (KA) approach to total knee arthroplasty (TKA) has recently increased in popularity. Accordingly, a number of derivatives have arisen and have caused confusion. Clarification is therefore needed for a better understanding of KA-TKA. Calipered (or true, pure) KA is performed by cutting the bone parallel to the articular surface, compensating for cartilage wear. In soft-tissue respecting KA, the tibial cutting surface is decided parallel to the femoral cutting surface (or trial component) with in-line traction. These approaches are categorized as unrestricted KA because there is no consideration of leg alignment or component orientation. Restricted KA is an approach where the periarthritic joint surface is replicated within a safe range, due to concerns about extreme alignments that have been considered ‘alignment outliers’ in the neutral mechanical alignment approach. More recently, functional alignment and inverse kinematic alignment have been advocated, where bone cuts are made following intraoperative planning, using intraoperative measurements acquired with computer assistance to fulfill good coordination of soft-tissue balance and alignment. The KA-TKA approach aims to restore the patients’ own harmony of three knee elements (morphology, soft-tissue balance, and alignment) and eventually the patients’ own kinematics. The respective approaches start from different points corresponding to one of the elements, yet each aim for the same goal, although the existing implants and techniques have not yet perfectly fulfilled that goal.

Difference between medial and lateral tibia plateau in the coronal plane: importance of preoperative evaluation for medial unicompartmental knee arthroplasty

BackgroundSetting bone cutting levels for different joint line orientations of the medial and lateral tibia plateaus in individual patients is not clear. We aimed to evaluate the difference between joint line orientation of the medial and lateral tibia plateaus relative to the horizontal line of mechanical axis of tibia as tibial plateau difference (TPD) for an optimal tibial bone cut in medial unicompartmental knee arthroplasty (UKA) and determine which factors could influence TPD. We aimed to investigate the effect of preoperative TPD on polyethylene liner size in medial UKA.MethodsTPD in the coronal plane were measured in 181 female patients (181 knees). To determine the morphology of proximal tibia according to the severity of osteoarthritis, the patients were classified into three groups based on diagnosis and treatment: 80 who underwent robot-assisted medial UKA, 45 who underwent total knee arthroplasty (TKA), and 56 with early-stage osteoarthritis (OA) who had conservative management. Also, we divided the medial UKA group into two groups according to TPD (greater than or less than 5 mm) and compared polyethylene liner sizes.ResultsNo significant difference was observed in TPD (p = 0.662), difference between the medial and lateral femoral condyle levels (p = 0.54), medial proximal tibial angle (p = 0.169), or posterior tibial slope (p = 0.466) among the three groups. Increased TPD was significantly associated with increased mechanical femorotibial angle(mFTA) (p < 0.01). The medial UKA group was divided into two groups according to TPD greater or less than 5 mm. Thicker polyethylene liners were used for groups with TPD greater than 5 mm (8.5 ± 0.7 mm versus 8.2 ± 0.3 mm, p = 0.01). Additionally, the proportion of patients using the thinnest polyethylene (8 mm) in each TPD group (greater or less than 5 mm) was higher in patients with TPD less than 5 mm (82.4% versus 58.7%, p = 0.038).ConclusionsPreoperative measurement of TPD is important to help surgeons predict the most appropriate bone cutting level in the coronal plane in primary medial UKA. Tibial bone resection would be likely to be thicker than needed in patients with increased TPD in medial UKA.

A Study of Surgical Accuracy with X-Ray-Based Patient-Specific Instrument (X3DPSI®) vs Conventional Instrument in Total Knee Arthroplasty Surgeries.

Patient-specific instruments (PSI) have been shown to be a good solution in getting accurate bone cuts in total knee arthroplasty (TKA) in many studies. However, the need for an extra CT/MRI makes the existing PSI method costly and unsafe. X-ray-based PSI can solve these problems, if proven to be accurate. The purpose of this study was to introduce a novel method to measure the performance of X-ray to 3D-based PSI (X3DPSI ® ) in achieving planned bone cuts by comparing with conventional instruments (CI). This was a prospective study of a total of ten patients undergoing TKA surgery. Preoperative full length lower limb scanogram was done with specialized calibration strap-on marker to develop X3DPSI ® which was used intraoperatively for the placement of guiding pins for the cutting jig. Similarly, intraoperative guide pins were placed using CI also. Calibrated intraoperative X-ray images, in AP and LAT view, were taken while the cutting-block guiding pins were placed on the distal femur and proximal tibia. These X-ray images were used to calculate the cutting plane alignments for femur and tibia and to simulate the postoperative hip-knee-ankle (HKA) angle and MAD (mechanical axis deviation), in a virtual Tabplan3D environment for both the methods. The results showed that there was a significant difference between the two methods in terms of femoral cutting plane angles and in terms of the HKA angles and MAD. There was no significant difference in the tibial cutting plane angles in the coronal plane. The mechanical axis alignment achieved based on the virtual cuts made using the X3DPSI ® was significantly better than the alignment achieved based on the cuts made using the CI, in terms of both HKA and MAD. This novel method of X-ray-based PSI is a low-cost alternative to CT/MRI-based PSI if found to be accurate in future planned studies.