Bony Cuts Research Articles

Subvastus approach improves intraoperative patellofemoral tracking in total knee arthroplasty for varus deformities – An in vivo study

Objectives: The subvastus approach has the theoretical advantages of protecting the extensor mechanism while securing the patellar blood supply, enhanced patellofemoral tracking, faster recovery, decreased post-operative pain, and shortened length of hospital stay at the expense of longer operative and tourniquet times. This study aimed to evaluate the effect of the subvastus approach on patellofemoral tracking. We hypothesize that being a more anatomical approach, the subvastus approach may improve patellofemoral tracking intraoperatively and decrease the necessity to release the lateral retinaculum during total knee replacement (TKR). Methods: In 54 consecutive cases presented with advanced varus osteoarthritis knee in a high-volume arthroplasty hospital from January 2022 to April 2022 and scheduled for cemented posterior stabilized TKR, patellofemoral tracking and the tightness of lateral retinaculum were evaluated intra-operatively all through the whole range of motion (ROM) of the knee by “No thumb test” and “Vertical patella test” subsequent doing the whole tibial and femoral bony cuts, proper sizing, completing soft-tissue release and gap balancing, and reaching the full ROM. Results: The “No thumb test” and “Vertical patella test” were negative in all the patients, and there was no intra-operative dislocation or subluxation. In addition, there was no need to release the lateral retinaculum in any of them. Conclusion: Implementing the subvastus approach during TKR surgeries, with subsequent preservation of the patellar attachment of the vastus medialis oblique muscle, allows for better tracking of the patella over the femur during surgery, resulting in a reduction in the necessity of performing lateral retinaculum release intraoperatively.

An Advanced Knee Simulator Model Can Reproducibly Be Used for Ligament Balancing Training during Total Knee Arthroplasty.

A critical and difficult aspect of total knee arthroplasty (TKA) is ligamentous balancing for which cadavers and models have played a large role in the education and training of new arthroplasty surgeons, although they both have several shortcomings including cost, scarcity, and dissimilarity to in vivo ligament properties. An advanced knee simulator (AKS) model based on computed tomography (CT) scans was developed in the setting of these challenges with cadavers and previous models. In this study, we compared the ligament balancing between AKS and human cadaveric knees to assess the validity of using the AKS for ligament balancing training during TKA. A CT scan of a TKA patient with varus deformity was used to design the AKS model with modular components, using three-dimensional printing. Three fellowship-trained arthroplasty surgeons used technology-assisted TKA procedure to plan and balance three cadaver knees and the AKS model. Medial and lateral laxity data were captured using manual varus and valgus stress assessments for cadavers and the model in an extension pose (10 degrees of flexion from terminal extension) and between 90 and 95 degrees for flexion. After preresection assessments, surgeons planned a balanced cruciate-retaining TKA. Following bony cuts and trialing, extension and flexion ligament laxity values were recorded in a similar manner. Descriptive statistics and Student's t-tests were performed to compare the cadavers and model with a p-value set at 0.05. Preresection medial/lateral laxity data for both extension and flexion were plotted and showed that the highest standard deviation (SD) for the cadavers was 0.67 mm, whereas the highest SD for the AKS was 1.25 mm. A similar plot for trialing demonstrated that the highest SD for the cadavers was 0.6 mm, whereas the highest SD for the AKS was 0.61 mm. The AKS trialing data were highly reproducible when compared with cadaveric data, demonstrating the value of the AKS model as a tool to teach ligament balancing for TKA and for future research endeavors.

Complications and Learning Curve Associated with an Imageless Burr-Based (CORI) Robotic-Assisted Total Knee Arthroplasty System: Results from First 500 Cases.

The use of robotic-assisted total knee arthroplasty (RA-TKA) is gaining traction. There is evidence to suggest that RA-TKA can help to optimize the precision and accuracy of implant positioning and that there may be protective effects on surrounding bony and soft tissues. Yet, there are important differences between the various RA-TKA systems currently on the market. One such newly introduced RA-TKA system uses imageless technology and performs bony cuts with the use of a burr-based device. The learning curve and complications unique to this system have yet to be assessed. We evaluated 500 consecutive RA-TKA cases using a newly developed burr-based and imageless system which were done by a single surgeon between the months of October 2021 and February 2023. Operative times were recorded and compared to the previous 150 conventional TKA cases allowing for the learning curve to be calculated using the CUSUM method. Intraoperative and postoperative complications were categorically profiled. The learning curve of this RA-TKA system was found to be 6 cases. Intraoperative complications included unintended bony over resection (n = 3), soft tissue injury (n = 2), and robotic system hardware (n = 2) or software (n = 2) malfunction. Postoperative complications consisted of superficial pin site infection (n = 1) and periprosthetic fracture near the pin sites (n = 1). There were no identified cases of prosthetic joint infection, instability events, or wound complications. The learning curve and the complication profile of a newly introduced imageless and burr-based RA-TKA system were described. This information serves to guide surgeons in adopting this technology and can counsel them regarding the potential pitfalls and challenges associated with its integration into practice. The work sheds light on the complexity and learning curve of the recently released imageless burr-based RA-TKA system. This important information is intended to help surgeons accept this cutting-edge technology by providing advice on any errors and difficulties that can occur when integrating it into clinical practice. This information can help surgeons navigate the complexities of integrating this new burr-based robotic technology into knee replacement procedures, enabling them to make well-informed decisions and receive guidance.

The Use of Bone Hook in the Retrieval of Tibial Bony Cut. Technical Tip

Total ankle replacement, is technically demanding. Intraoperative malleolar fracture may result because of levering on the malleoli whilst removing the distal tibial cut. The technique described of using bone hook to retrieve the distal tibial bone cut is safe and easy.

Robotic Assisted Total Knee Arthroplasty in Arthrofibrosis or the Preoperatively Stiff Knee: A Case Report

Total knee arthroplasty (TKA) for arthrofibrosis or preoperatively stiff knees can present a set of difficult problems that challenge both the patient and surgeon. Patients with limited preoperative range of motion (ROM) are inherently at risk for worse outcomes. Prior literature has demonstrated the utility of robotic-assisted TKA (raTKA) regarding gap balancing and coronal deformity, however it has not been previously described in context of the preoperatively stiff knee. Here, we report a case of a patient undergoing primary TKA for severe osteoarthritis with significant preoperative stiffness resulting in severely limited ROM of only 5 degrees. This was performed with the use of a navigated raTKA system in conjunction with dynamic predictive balancing technology. With this method, the knee was balanced through bony cuts without the need for extensive soft tissue releases. This patient had excellent improvement in ROM and KOOS Scores at 3-month follow up. This patient’s early post-operative results demonstrate the potential benefits of utilizing raTKA for preoperative stiff knees and may lay groundwork for future literature.

The Scientific Evolution of Periacetabular Osteotomy: A Global Review.

It is well-known that hip disorders are frequently of bony origin related to an underlying pathomorphology. A fundamental understanding of morphology and biomechanics is therefore of essential importance for a targeted approach in defining treatment plans. Treatment is frequently based on altering bony morphology, for which a set of effective techniques have been proposed. Periacetabular osteotomy (PAO) allows for reorientation of the acetabulum and powerful correction of acetabular coverage. The revolutionary aspect of PAO compared to prior osteotomies lies in maintenance of the integrity of the posterior column. This allows for a substantial increase in primary stability, a larger bony surface for healing, and simple reorientation of the acetabular fragment that is free of posterior ligamentous restraints. The results for dysplasia are very promising. Indications have been refined by studies revealing that the presence of degenerative changes and age > 40 years at the time of surgery represent prognostic factors of poorer outcome. Indications have also been broadened to include acetabular retroversion (with posterolateral dysplasia) and borderline hip dysplasia. A glimpse at the future would reflect major advances related to individual planning, surgical training, and precise surgical conduction. In the era of digitalization, augmented reality may assist in performing bony cuts and act as an aid for some of the blind ischial and retro-acetabular cuts. Innovations in perioperative management will enhance recovery after the procedure and allow for early recovery programs with optimized protocols of pain management. Considering that the success of PAO in the young is comparable to the success of hip arthroplasty in the old, PAO should be considered one of the pillars of modern orthopedic surgery.

Mechanical Alignment in Total Knee Arthroplasty for Varus Knee Osteoarthritis Leads to Significant Tibial Bone Loss.

Background Obtaining a neutral postoperative alignment is said to be a guiding principle for performing a successful total knee arthroplasty (TKA). There are many different alignment philosophies and surgical techniques to attain the goal of proper alignment. This study aimed to radiologically measure the difference in the amount of tibial bony resection required to perform a mechanical alignment versus an anatomic alignment TKA. Methods Two observers retrospectively reviewed the long leg radiographs of 100 patients (61 females and 39 males) listed for TKA between 2015 and 2018, measuring the amount of tibial bony resection required to achieve mechanical or anatomic alignment TKA. Results These radiographs' overall lower limb mechanical axis ranged between 16° varus and 17.6° valgus (mean 4.4° varus, standard deviation (SD) 6.64). By referencing 4 mm from the worn side, the mean resection needed from the normal side of the tibial plateau is 7.6 mm in the mechanical alignment measurement and 5.2 mm in the anatomical alignment measurement (p<0.0001). Therefore, 17% of mechanical alignment cuts require a tibial cut of more than 10 mm (mean 12.382 mm). No anatomical alignment measurements exceed 10 mm. When a virtual tibial cut >10 mm is required, the medial proximal tibial angle (MPTA) is a stronger predictor of deformity than the mechanical axis. Conclusion This radiological study shows that an anatomical alignment tibial cut is more bone conserving on the tibia than a mechanical alignment tibial cut and may lead to less asymmetry of the bony cuts and greater bony preservation, but clinical correlation is needed.

Cervical Anatomical Landmarks Indicate the Amount of Vertebra Resection during ACAF Surgery: A Semi-Quantitative Anatomical Parameter Study on Imaging Data.

ObjectiveWith the innovation and development of cervical spine surgical procedures, there is currently a lack of new and reliable data on cervical anatomical landmarks. The purpose of this study is to measure the CT data of the cervical vertebrae of healthy volunteers, so as to make up for the missing part of the measured value of cervical vertebra bone markers, and provide data support for the safety and accuracy of anterior controllable antedisplacement and fusion (ACAF) surgery.MethodsFrom January 2019 to January 2020, the cervical computed tomography (CT) scan image data of volunteers in Changhai Hospital and Zhabei Hospital were randomly selected. The radiological parameters included three parameters were measured in the upper lamina plane. a: the distance from the anterior edge of the vertebral body to the anterior edge of the bilateral uncinate joint; c1: the sagittal diameter of the vertebral body; and d: the distance between the anterior edge of the uncinate joint. Three parameters were measured in the pedicle plane. b: the vertical distance from the anterior edge of the vertebral body to the junction line between the two lateral processes; c2: the sagittal diameter of the vertebral body; e: the transverse diameter of the vertebral body; and f: the sagittal diameter of the vertebral canal. The correlation ratios were calculated: a/c1, b/c2, a/f, b/f, d/e. The data between the two groups were compared by independent sample t‐test.ResultsFinally, 51 patients were included in this study, 18 males and 33 females, with an average age of 47.9 years (21–72 years). The maximum values of seven parameters measured were all at C7. The minimum b value was at C5, and the minimum f value was at C4. The minimum values of the other five parameters were all at C3, and there was an increasing relationship from C3 to C7 (P < 0.05). There was significant difference between male and female with regard to c1, c2, e and d values (P < 0.05). No significant differences were observed between men and women regard to the ratio of related parameters (a/c1, b/c2, a/f, b/f, d/e).ConclusionsAnatomical consideration of this area is useful to estimate amount of vertebral body resection when performing the bony cut made in ACAF surgery; however, pre‐operative examinations with appropriate radiographic analysis are also recommended.

Total Knee Arthroplasty in Valgus Deformity Made Easy Using Robotic-assisted Predictive Balancing Technique

Total knee arthroplasty (TKA) performed for valgus osteoarthritis (OA) presents a challenge to the arthroplasty surgeon in regards to achieving appropriate soft tissue balance and alignment. Robotic assisted surgery (RAS) with navigation (NAV) has been proposed as a potential solution to assist surgeons when performing these difficult cases. Here, we present the case of a complex primary TKA in a patient with posttraumatic valgus arthritis performed using a novel RAS system with NAV. Appropriate balance was unable to be achieved with bony cuts alone, as the knee was found to be tight laterally in extension following bone preparation. Soft tissue releases were ultimately required. Use of the novel RAS system with NAV allowed for a titrated soft tissue release resulting in a balanced knee without overcorrection of the patient’s deformity. We also present a similar case of a patient with valgus knee OA in which there was residual tightness laterally in flexion. The different management strategies for each of these cases is discussed. Finally, we provide a review of the available literature regarding TKA in valgus knee OA and propose a new classification system and treatment algorithm that can be employed using a novel RAS system with predictive balancing technology to achieve optimal alignment and soft tissue balancing in valgus knees that remain unbalanced following bony cuts.

Impact of Component Alignment and Soft Tissue Release on 2-Year Outcomes in Total Knee Arthroplasty

BackgroundThe objective of this study was to investigate the impact of alignment and soft tissue release on patient outcomes following total knee arthroplasty (TKA). MethodsIn a multicenter study, soft tissue releases during TKA were prospectively documented in 330 robotic-assisted TKAs. Knee Injury and Osteoarthritis Outcome Scores (KOOS) were captured postoperatively. Delphi analysis was used to determine inlier and outlier component alignment boundaries: Tibia Coronal (TC): ±3°, Femur Coronal (FC): ±3°, Femoral Axial (FA): 3°Int-6°Ext, Hip-Knee-Ankle (HKA): 3°Val-4°Var, and Tibiofemoral Axial (TFA): 3°Int-6°Ext. Kruskal–Wallis analysis of variance tests were used to compare groups. ResultsNo significant differences were found between any individual or grouped inlier and outlier alignment criterion and KOOS at any timepoint. Outlier alignment frequencies were: TC: 0%, FC: 12%, FA: 8%, HKA: 9%, TFA: 8%, and Any: 23%. Soft tissue releases were performed in 18% of cases. Knees with soft tissue releases reported significantly worse KOOS scores at: 6M: Symptoms (80.0 versus 75.3, P = .03), activities of daily living (ADL) (86.2 versus 80.8, P = .030), quality of life (70.1 versus 60.9, P = .008), 12M ADL (90.0 versus 85.1, P = .023), and 24M ADL (91.9 versus 87.2, P = .016). A higher proportion of patients achieved Minimal Clinically Important Difference for pain at 6 months for those having no releases versus released (92.3% versus 81.0%, P = .021). No significant associations were found between preoperative deformity and preoperative or postoperative KOOS. ConclusionThe addition of soft tissue releases after bony cuts is associated with worse KOOS scores out to 2 years and was more prevalent in knees with worse deformity, while no such association was found for alignment.

No Benefit to Sensor-guided Balancing Compared With Freehand Balancing in TKA: A Randomized Controlled Trial.

Soft tissue balancing in TKA has traditionally relied on surgeons' subjective tactile feedback. Although sensor-guided balancing devices have been proposed to provide more objective feedback, it is unclear whether their use improves patient outcomes. We conducted a randomized controlled trial (RCT) comparing freehand balancing with the use of a sensor-guided balancing device and evaluated (1) knee ROM, (2) patient-reported outcome measures (PROMs) (SF-12, WOMAC, and Knee Society Functional Scores [KSFS]), and (3) various surgical and hospital parameters (such as operative time, length of stay [LOS], and surgical complications) at a minimum of 2 years of follow-up. A total of 152 patients scheduled for primary TKA were recruited and provided informed consent to participate in this this study. Of these, 22 patients were excluded preoperatively, intraoperatively, or postoperatively due to patient request, surgery cancellation, anatomical exclusion criteria determined during surgery, technical issues with the sensor device, or loss to follow-up. After the minimum 2-year follow-up was accounted for, there were 63 sensor-guided and 67 freehand patients, for a total of 130 patients undergoing primary TKA for osteoarthritis. The procedures were performed by one of three fellowship-trained arthroplasty surgeons (RPS, HJC, JAG) and were randomized to either soft tissue balancing via a freehand technique or with a sensor-guided balancing device at one institution from December 2017 to December 2018. There was no difference in the mean age (72 ± 8 years versus 70 ± 9 years, mean difference 2; p = 0.11), BMI (30 ± 6 kg/m 2 versus 29 ± 6 kg/m 2 , mean difference 1; p = 0.83), gender (79% women versus 70% women; p = 0.22), and American Society of Anesthesiology score (2 ± 1 versus 2 ± 1, mean difference 0; p = 0.92) between the sensor-guided and freehand groups, respectively. For both groups, soft tissue balancing was performed after all bony cuts were completed and trial components inserted, with the primary difference in technique being the ability to quantify the intercompartmental balance using the trial tibial insert embedded with a wireless sensor in the sensor-guided cohort. Implant manufacturers were not standardized. Primary outcomes were knee ROM and PROMs at 3 months, 1 year, and 2 years. Secondary outcomes included pain level evaluated by the VAS, opioid consumption, inpatient physical therapy performance, LOS, discharge disposition, surgical complications, and reoperations. There was no difference in the mean knee ROM at 3 months, 1 year, and 2 years postoperatively between the sensor-guided cohort (113° ± 11°, 119° ± 13°, and 116° ± 12°, respectively) and the freehand cohort (116° ± 13° [p = 0.36], 117° ± 13° [p = 0.41], and 117° ± 12° [p = 0.87], respectively). There was no difference in SF-12 physical, SF-12 mental, WOMAC pain, WOMAC stiffness, WOMAC function, and KSFS scores between the cohorts at 3 months, 1 year, and 2 years postoperatively. The mean operative time in the sensor-guided cohort was longer than that in the freehand cohort (107 ± 0.02 versus 84 ± 0.04 minutes, mean difference = 23 minutes; p = 0.008), but there were no differences in LOS, physical therapy performance, VAS pain scores, opioid consumption, discharge disposition, surgical complications, or percentages of patients in each group who underwent reoperation. This RCT demonstrated that at 2 years postoperatively, the use of a sensor-balancing device for soft tissue balancing in TKA did not confer any additional benefit in terms of knee ROM, PROMs, and clinical outcomes. Given the significantly increased operative time and costs associated with the use of a sensor-balancing device, we recommend against its routine use in clinical practice by experienced surgeons. Level I, therapeutic study.

Modified Recession Wedge Trochleoplasty

Background: Trochlear dysplasia represents one of the main anatomic risk factors for patellar instability, with risk of failure and unfavorable clinical outcomes in patients with unaddressed dysplasia undergoing patellar stabilization. Indications: Patients with trochlear dysplasia characterized by supratrochlear prominence (DeJour B or D) and recurrent patellar instability, especially following failed soft tissue or bony stabilization. This technique addresses an anterior trochlea without pathologic convexity, as convexity may require conversion to other techniques for groove deepening (eg, DeJour “thick flap” or Schottle “thin flap”). Technique Description: A 6-cm lateral parapatellar arthrotomy is created. A marking pen is used to identify the native center of the trochlea, as well as the location of the planned resection and bony hinge point laterally. An osteotome is used to remove a wedge of bone proximally, such that the posterior aspect of the osteotomy is in line with the anterior femoral cortex. A resection guide is then used to perforate the lateral cortex, with care to avoid damaging the cartilage, and carried laterally and distally to ensure the bony cuts are connected, creating the bony flap. To ensure that all bony bridges are eliminated, the arthroscope is placed into the osteotomy to visualize reduction of the trochlea with manual pressure. A knotless PEEK anchor loaded with 8 loaded sutures is then placed on the roof of the trochlear notch. Sutures are then secured using anchors placed at the center of the trochlea, at the superolateral corner and far lateral edge of the trochlea to reduce the osteotomy, with 2 to 3 sutures placed in each anchor depending on surgeon preference. Results: Trochleoplasty has been reported to decrease the rate of recurrent patellar dislocation while improving mean Kujala score and knee function. Benefits of trochleoplasty must be balanced against the high rate of potential complications, primarily pain and decreased knee range of motion, secondary to the technical challenges and steep learning curve inherent to effectively performing the procedure. Discussion/Conclusion: Patients with recurrent patellar instability with trochlear dysplasia and failed prior stabilization may experience improved stability and outcomes following trochleoplasty.

Individualized Functional Knee Alignment in Total Knee Arthroplasty: A Robotic-assisted Technique

Introduction: The use of robotic technology is becoming a well-recognized alternative to conventional total knee arthroplasty (TKA). The quantitative soft tissue information generated in robotic surgery can be used to balance the knee and achieve functional alignment (FA) of the components. This paper describes a novel FA technique using an individualized preoperative plan that is then adjusted to achieve soft tissue balance. Materials and Methods: We report on surgical technique, indications, considerations, and complications after our experience of performing 650 functionally aligned TKAs. We collected 2-year patient reported outcomes on 165 TKAs in this series (165 of 193 TKAs have reached 2 years follow-up in the series of 650 TKAs; 85% follow-up rate). Results: We found significant postoperative improvements with few infections and no revisions for mechanical reasons 2 years after surgery with this technique. Patients had improved knee range-of-motion (105 degrees° flexion preoperatively vs. 125 degrees flexion postoperatively; P&lt;0.001), higher Forgotten Joint Scores (17 preoperatively vs. 77 postoperatively; P&lt;0.001), improved Oxford Knee Scores (22 preoperatively vs. 43 postoperatively; P&lt;0.001), higher KOOS Jr scores (48 preoperatively vs. 88 postoperatively; P&lt;0.001) and lower visual analogue score pain scores (70 preoperatively vs. 12 postoperatively; P&lt;0.001) 2 years postoperatively. Discussion: The described surgical technique is a promising method for conducting a robotic TKA. Benefits of FA include improved efficiency with preresection balancing, reduced soft tissue releases compared with a mechanical alignment technique, and accurate bony cuts with robotic assistance. Further studies are required to compare this technique with established methods to determine any differences in outcomes.

Results of Robotic-Assisted Versus Manual Total Knee Arthroplasty at 2-Year Follow-up.

Robotic-assisted technology has been developed to optimize the consistency and accuracy of bony cuts, implant placements, and knee alignments for total knee arthroplasty (TKA). With recently developed designs, there is a need for the reporting longer than initial patient outcomes. Therefore, the purpose of this study was to compare manual and robotic-assisted TKA at 2-year minimum for: (1) aseptic survivorship; (2) reduced Western Ontario and McMaster Universities Osteoarthritis Index (r-WOMAC) pain, physical function, and total scores; (3) surgical and medical complications; and (4) radiographic assessments for progressive radiolucencies. We compared 80 consecutive cementless robotic-assisted to 80 consecutive cementless manual TKAs. Patient preoperative r-WOMAC and demographics (e.g., age, sex, and body mass index) were not found to be statistically different. Surgical data and medical records were reviewed for aseptic survivorship, medical, and surgical complications. Patients were administered an r-WOMAC survey preoperatively and at 2-year postoperatively. Mean r-WOMAC pain, physical function, and total scores were tabulated and compared using Student's t-tests. Radiographs were reviewed serially throughout patient's postoperative follow-up. A p < 0.05 was considered significant. The aseptic failure rates were 1.25 and 5.0% for the robotic-assisted and manual cohorts, respectively. Patients in the robotic-assisted cohort had significantly improved 2-year postoperative r-WOMAC mean pain (1 ± 2 vs. 2 ± 3 points, p = 0.02), mean physical function (2 ± 3 vs. 4 ± 5 points, p = 0.009), and mean total scores (4 ± 5 vs, 6 ± 7 points, p = 0.009) compared with the manual TKA. Surgical and medical complications were similar in the two cohorts. Only one patient in the manual cohort had progressive radiolucencies on radiographic assessment. Robotic-assisted TKA patients demonstrated improved 2-year postoperative outcomes when compared with manual patients. Further studies could include multiple surgeons and centers to increase the generalizability of these results. The results of this study indicate that patients who undergo robotic-assisted TKA may have improved 2-year postoperative outcomes.

Use of Fulcrum Positioning as a Balancing Tool During Total Knee Arthroplasty on a Robotic Platform.

Total knee arthroplasty is a common procedure performed to improve pain and dysfunction attributed to arthritis, yet postoperative patient dissatisfaction rates remain relatively high. Patient satisfaction and outcomes have been linked to successful joint gap balancing in the coronal and sagittal planes intraoperatively. In previously described balancing techniques, the fulcrum used for alignment changes is customarily centered on the intramedullary axis generating symmetric changes in medial and lateral gaps. We propose a novel technique in the literature that, with the use of robotic-arm assisted technology or similar systems, allows manipulation of the fulcrum center of rotation during pre-resection planning and intraoperative gap establishment before bony cuts to asymmetrically influence medial and lateral, flexion and extension gaps to aid in balancing during total knee arthroplasty.

Kinematic versus mechanically aligned total knee arthroplasty: no difference in frequency of arthroscopic lysis of adhesions for arthrofibrosis.

Arthrofibrosis is a condition that can cause excessive scar tissue formation, leading to painful restriction of joint motion. Following total knee arthroplasty (TKA), significant arthrofibrosis can result in permanent deficits in range of motion (ROM) if not treated. Although arthroscopic lysis of adhesions (ALOA) reliably improves post-TKA ROM if performed in a timely fashion, it exposes patients to additional anesthesia, heightens the risk of infection, and increases overall medical expenses. Kinematically aligned TKA has emerged as an alternative method to mechanically aligned, basing bony cuts off of the patient's pre-arthritic anatomy while limiting need for soft tissue and ligamentous releases. This study aimed to determine whether there is a difference in the frequency of post-TKA arthrofibrosis requiring ALOA between kinematic and mechanically aligned TKA. Between 2012 and 2019, a retrospective analysis was conducted based on a single surgeon's experience. Two cohorts were made based on alignment technique. Postoperatively, patients were diagnosed with arthrofibrosis and indicated for ALOA if they had functional pain with < 90 degrees of terminal flexion at 6weeks postoperatively despite aggressive physical therapy. Frequency of ALOA was recorded for each cohort and was regressed using independent samples t-test. The results showed no significant difference between the mechanical and kinematic cohorts for frequency of ALOA following TKA (13.2% vs. 7.3%; p = 0.2659). However, the kinematic cohort demonstrated significantly greater post-ALOA ROM compared to the mechanical group (129° vs. 113°; p = 0.0097). Future higher-powered, prospective studies are needed to clarify whether a significant difference in rates of MUA/ALOA exists between the two alignment techniques.

Conventional instruments are more accurate for measuring the depth of the tibial cut than computer-assisted surgery in total knee arthroplasty: a prospective study.

The most commonly used tool for implant positioning are conventional instruments (CI) followed by computer-assisted surgery (CAS). A number of studies have investigated the cutting error of the tibial component when CAS is used, but most of them were focused on the cutting angles. The accuracy of CAS to determine the depth of the cut has not received much attention, even though implications are similar or worse, than with an angle mismatch. This was an ethics board approved, prospective study of 23 consecutive varus TKAs by a single surgeon. Implant positioning was performed using CAS; however, the depth of the tibial cut was determined with both CAS and CI. Targeted alignment was the mechanical axis and 3° of posterior slope. The planned and the achieved cut, as determined by CAS needed to match. The achieved cut was then measured using a caliper and compared to the depth of the cut as per CAS. Medial and lateral cuts were analyzed separately. Analysis of variance and Bland-Altman plots were used for the comparison. Mean medial navigated cut was 6.3 (± 2.2)mm, mean measured medial cut was 6.6 (± 2.3)mm. Mean lateral navigated cut was 8.9 (± 1.8)mm, mean measured lateral cut was 8.8 (± 1.5)mm. There was a statistical significance for both the medial (p < 0.001) and the lateral (p = 0.004) navigated and measured cuts. The results of this study suggest that the tibial cut depth, measured by the navigation, does not match the actual bony cuts performed, even if a perfect cut was achieved in both sagittal and coronal plane. Surgeons should be aware of the measurement error in the navigation system and potentially add an additional step for verifying the achieved depth of the cut.

Active maximum flexion after total knee arthroplasty is not related to posterior tibial slope, body mass index, or patient satisfaction: A retrospective cohort study

Background: Postoperative active maximum flexion is a major contributor to effective knee function after total knee arthroplasty (TKA). The lack of posterior tibial slope and a high body mass index (BMI) have been identified among the causative factors of reduced maximum flexion. This study investigated the correlation between these factors and maximum flexion achieved. Methods: All patients included in this retrospective study had a primary navigated TKA using Columbus® CR-knee implants (Aesculap, Tuttligen, Germany) and the Orthopilot® (Aesculap, Tuttligen, Germany) navigation system. At the 6-week review patients underwent a CT. At 1 yr, active flexion was measured by independent arthroplasty practitioners, and patient satisfaction was recorded. All CT measurements were taken by an independent radiologist. Posterior slope was indicated by a positive value. Results: One hundred and eighty-six knees were included. The mean patient age was 68 yr and mean BMI was 31.0. The mean maximum active flexion at 1 yr was 103 degrees (SD 9 degrees, range, 83 to 130 degrees). The mean posterior tibial slope (bony cut) was 2 degrees (SD 2 degrees, range −2 to 5 degrees). There was no correlation between posterior tibial slope and maximum flexion, r=0.086 (95% CI −0.058 to 0.227, P=0.245) between flexion and BMI, r=−0.112 (95% CI −0.251 to 0.032, P=0.129). There was a weak correlation between posterior slope and extension achieved, r=0.198 (95% CI 0.056 to 0.332, P=0.007), but this had little clinical predictive value. There was no link between either maximum flexion or patient satisfaction. Conclusions: In this study, no relationship between posterior tibial slope or BMI and the degree of achieved active maximum flexion was found. Consequently, other factors should be considered when attempting to increase the maximum flexion achieved. Level of Evidence: Level III.

Immersive Surgical Anatomy of the Frontotemporal-Orbitozygomatic Approach.

The frontotemporal-orbitozygomatic (FTOZ) approach is widely used for accessing anterolateral lesions in skull base surgery. Many studies have described the technique and quantified the surgical exposure and freedom provided by the FTOZ approach. However, few studies have provided a detailed analysis of the technique and surgical landmarks using three-dimensional (3D) models. In this study, we aimed to create a collection of volumetric models (VMs) and stereoscopic media on the step-by-step surgical technique of the FTOZ approach using cadaveric dissections. The FTOZ approach was divided into eight major steps: positioning, incision of the skin, dissection of scalp flap, mobilization of the temporalis muscle, dissection of periorbita, craniotomy, drilling of basal structures, and dural opening. The MacCarty keyhole and inferior orbital fissure are major surgical landmarks that were referenced for the six bony cuts. Photogrammetry and structured light scanning were used to construct high-resolution VMs. We illustrated the two-piece FTOZ craniotomy, followed by the one-piece and three-piece FTOZ craniotomies. Stereoscopic images, videos, and VMs were produced for each step of the surgical procedure. In addition, the mini-orbitozygomatic (MOz) and orbitopterional (OPt) approaches were considered and described as possible alternatives to the FTOZ approach. Recent advances in 3D technology can be implemented in neurosurgical practice to further enhance our spatial understanding of neurovascular structures. Surgical approaches should be carefully selected and tailored according to the patient’s unique pathology and needs.

Management of Extra-articular Deformity in the Setting of Total Knee Arthroplasty.

Extra-articular deformities of the femur and tibia in conjunction with advanced knee osteoarthritis pose unique challenges for the arthroplasty surgeon. Careful preoperative planning is needed to evaluate both the intra- and extra-articular deformities and to determine the best route to total knee arthroplasty. An intra-articular compensatory correction can typically be performed if the extra-articular deformity is distant from the joint or if preoperative templating shows that bony cuts do not interfere with ligamentous attachments. Staged osteotomy followed by arthroplasty is beneficial in severe cases in which bony cuts are excessive or would interfere with soft-tissue structures and in cases with leg-length discrepancy. Osteotomies can be performed percutaneously and fixed with intramedullary nails, external fixators, or plate and screw constructs. Ligamentous laxity after correction and risk of peroneal nerve injury are increased in extra-articular deformity cases and must be considered during the knee arthroplasty procedure with increased implant constraint and patient counseling, respectively. Computer-assisted navigation has an emerging role in total knee arthroplasty in patients with extra-articular deformity.