Predicting postoperative coronal alignment after fixed-bearing unicompartmental knee arthroplasty using a new morphological assessment method: the arithmetic hip-knee-ankle angle.

PURPOSE: Only a few reports have been published so far on factors that predict postoperative coronal alignment after unicompartmental knee arthroplasty (UKA). The purpose of this study is to clarify the relationship between the arithmetic hip-knee-ankle angle (aHKA) and postoperative coronal alignment after medial fixed-bearing UKA. METHODS: One hundred and one consecutive patients (125 knees) who underwent medial fixed-bearing UKA were assessed. Pre- and postoperative coronal HKA angles, lateral distal femoral angle (LDFA), medial proximal tibial angle (MPTA), and the thickness of the tibial and femoral bone cut were measured. aHKA was calculated as 180° - LDFA + MPTA. Correlations between postoperative HKA angle and aHKA, LDFA, and MPTA were investigated by single regression analysis. After the patients were divided into three groups according to the postoperative HKA angle, i.e., HKA angle > 180°, 175° < HKA angle ≤ 180°, and HKA angle ≤ 175°, aHKA, LDFA, MPTA, preoperative HKA angle, and the thickness of the distal femoral as well as tibial bone cut were compared among the three groups. RESULTS: aHKA and MPTA were positively correlated with postoperative HKA angle, while no correlation was found between postoperative HKA angle and LDFA. Among the three groups classified by postoperative HKA angle, significant differences were found in aHKA, MPTA, and preoperative HKA angle, while no significant difference was found in LDFA and the amount of distal femoral and tibial osteotomies. CONCLUSIONS: aHKA was correlated with postoperative HKA angle after medial fixed-bearing UKA, which was probably due to the influence of MPTA.

Small change in the arithmetic hip-knee-ankle angle during unicompartmental knee arthroplasty improves early postoperative functional outcomes.

INTRODUCTION: The optimal lower-limb alignment after unicompartmental knee arthroplasty (UKA) remains controversial. This study aimed to investigate the optimal lower-limb alignment for functional improvement in the early post-UKA period. We hypothesized that a small change (Δ) in the arithmetic hip-knee-ankle (aHKA) angle during surgery would result in better postoperative knee function. MATERIALS AND METHODS: This single-centered, retrospective study analyzed 91 patients (91 knees) who underwent UKA from April 2021 and December 2022. Preoperative and postoperative standing whole-leg radiographs were used to evaluate the mechanical HKA angle and aHKA angle. The aHKA angle was calculated from the medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA). We defined restored aHKA angle as a postoperative aHKA angle within ± 3° of the preoperative aHKA angle. Functional improvement was evaluated using the preoperative and one-year postoperative Knee Society Scoring 2011 (KSS 2011). A multivariate regression analysis was performed to investigate the optimal lower-limb alignment for functional improvement. RESULT: Postoperative restored aHKA angle (p = 0.020) was the only significant factor for improved KSS 2011 scores. Postoperative restored aHKA angle was obtained in 64 patients (70%). ΔMPTA (p < 0.001) and ΔLDFA (p = 0.037) were significant factors associated with a postoperative restored aHKA angle. CONCLUSIONS: UKA restores the native knee, including resurfacing constitutional alignment and medial collateral ligament tension. Minimal change in the aHKA angle during UKA improves the functional outcomes of the knee during the early postoperative period, consistent with the minimally invasive surgical concept of UKA.

Deep learning-based landmark recognition and angle measurement of full-leg plain radiographs can be adopted to assess lower extremity alignment.

PURPOSE: Evaluating lower extremity alignment using full-leg plain radiographs is an essential step in diagnosis and treatment of patients with knee osteoarthritis. The study objective was to present a deep learning-based anatomical landmark recognition and angle measurement model, using full-leg radiographs, and validate its performance. METHODS: A total of 11,212 full-leg plain radiographs were used to create the model. To train the data, 15 anatomical landmarks were marked by two orthopaedic surgeons. Mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), and hip-knee-ankle angle (HKAA) were then measured. For inter-observer reliability, the inter-observer intraclass correlation coefficient (ICC) was evaluated by comparing measurements from the model, surgeons, and students, to ground truth measurements annotated by an orthopaedic specialist with 14 years of experience. To evaluate test-retest reliability, all measurements were made twice by each measurer. Intra-observer ICCs were then derived. Performance evaluation metrics used in previous studies were also derived for direct comparison of the model's performance. RESULTS: Inter-observer ICCs for all angles of the model were 0.98 or higher (p < 0.001). Intra-observer ICCs for all angles were 1.00, which was higher than that of the orthopaedic specialist (0.97-1.00). Measurements made by the model showed no significant systemic variation. Except for JLCA, angles were precisely measured with absolute error averages under 0.52 degrees and proportion of outliers under 4.26%. CONCLUSIONS: The deep learning model is capable of evaluating lower extremity alignment with performance as accurate as an orthopaedic specialist with 14 years of experience. LEVEL OF EVIDENCE: III, retrospective cohort study.

The distal femur trochlear groove appears to compensate for tibial deformity but not femoral deformity in an investigation of five-hundred and seventy-nine cadaveric skeletons.

BACKGROUND: The etiology of patellofemoral disorders is multifactorial. Preoperative patellofemoral anatomy evaluation is of great importance in patients undergoing surgery for patellofemoral disorders. Although anatomical risk factors of patellofemoral disorders have been thoroughly investigated in clinical and radiological studies, there are sparse data regarding the association between trochlear dysplasia with other anatomical parameters. This study sought to explore those associations using a large osteological collection. METHODS: Five-hundred and seventy-nine cadaveric skeletons were obtained from the Hamann-Todd osteological collection. Mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), femoral version, tibial torsion, lateral position of the tibial tubercle, and femoral length were modeled as predictors of medial and lateral flange height of the distal femur trochlea at various degrees of knee flexion. RESULTS: The average age and standard deviation for the 1158 lower extremities analyzed was 55.9 ± 10.2 years. There were 500 males (86%) and 79 females. Increasing MPTA or tibial valgus predicted increasing lateral femoral flange height at 0, 30, and 50 degrees of knee flexion [(standardized beta 0.111, p = 0.01), (standardized beta 0.129, p < 0.001), and (standardized beta 0.186, p < 0.001), respectively]. Increasing internal tibial torsion predicted increased medial flange height at 30 and 50° [(standardized beta - 0.114, p = 0.006), (standardized beta - 0.108, p = 0.006), respectively]. Increased femoral retroversion predicted increasing lateral flange height at 0 and 30 degrees [(standardized beta - 0.105, p = 0.005), (standardized beta - 0.098, p = 0.004), respectively]. CONCLUSIONS: To maintain the equilibrium necessary for effective patellar tracking, the depth of trochlear groove appears to effectively compensate for some of the anatomical parameters of the proximal tibia associated with patellofemoral disorders, and appears to be less influenced by femoral alignment. The clinical relevance of these findings warrants further investigation, and emphasizes the importance of carefully assessing the lower limb alignment in the management of patellofemoral disorders.

Femoral morphology affects postoperative alignment of the lower extremities in hybrid closed-wedge high tibial osteotomy.

INTRODUCTION: This study aimed to determine correction error predictors of lower extremitiy alignment after hybrid closed-wedge high tibial osteotomy (HCWHTO). MATERIALS AND METHODS: From 2011 to 2015, 102 knees in 75 patients with medial compartment knee osteoarthritis of the knee and varus knee deformities who underwent HCWHTO were evaluated in this retrospective study with a minimum 2-year follow-up. Preoperative radiological parameters including weight-bearing line ratio (WBL ratio), mechanical leg axis angle, mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), and JLCA under varus or valgus stress were measured. The knees were divided into the following three groups based on the WBL ratio on average 54 months after procedure: acceptable (WBL crossing the tibial plateau between 50 and 70%), under-correction (< 50%), and overcorrection (> 70%). A multiple regression analysis was performed to evaluate predictors that could influence postoperative WBL ratio and cut-off values of predictive preoperative factors was analysed. RESULTS: Significant differences in pre- and postoperative WBL ratios and mechanical leg axis angles were found. Preoperative mLDFA in the under-correction group (89.4° ± 2.1°) was significantly higher than that in the overcorrection group (87.4° ± 2.2°) (p = 0.015), while other preoperative parameters revealed no significant differences. The postoperative MPTA in the under-correction group (92.1° ± 3.7°) was significantly lower than that in the other two groups (p = 0.005 and p = 0.0001, respectively), while there was no significant change between the acceptable (94.6° ± 3.4°) and the overcorrection (96.7° ± 3.2°) groups. Multiple regression analysis revealed that mLDFA (ß = - 0.316; p = 0.010) had a significant impact on postoperative WBLR. The cut-off value for under-correction of mLDFA was 89.5°and sensitivity and specificity were 53.6 and 71.6%, respectively (p = 0.014). CONCLUSIONS: Preoperative mLDFA is significantly associated with postoperative alignment in HCWHTO. While postoperative MPTA is important, disregarding the preoperative mLDFA may bears a high risk of malcorrection. Varus alignment of the knee with larger mLDFA may be an indication for not only HCWHTO, but also for distal femoral osteotomy.

Relationship between lower limb torsion and coronal morphologies of the femur and tibia in patients with medial knee osteoarthritis.

BACKGROUND: To investigate the relationship between femoral or tibial torsion and hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), or mechanical medial proximal tibial angle (mMPTA) in patients with medial knee osteoarthritis (OA). METHODS: A total of 75 knees were enrolled. Femoral and tibial torsions were measured by superimposing the axial planes of computed tomography images. The relationship between femoral or tibial torsion and HKA, mLDFA, or mMPTA on radiographs was examined. RESULTS: The mean femoral torsion was 12.2 ± 8.5° internally; femoral internal and external torsions were observed in 70 and 5 knees, respectively. The mean tibial external torsion was 18.0 ± 7.4° externally; tibial external torsion was observed in all 75 knees. Femoral internal and tibial external torsions increased with lower mMPTA (r = 0.33, P = 0.003; r = - 0.32, P = 0.005, respectively) but were not related to HKA or mLDFA. CONCLUSION: Femoral and tibial torsions were correlated with varus inclination of the proximal tibia in patients with medial knee OA.

Functional Outcome of Mechanical Alignment in Total Knee Arthroplasty Surgery: A Short-Term Cohort Study at an Indian Tertiary Care Hospital.

Background: In severe arthritis cases, goal of total knee arthroplasty (TKA) management is to attain pain-free joint and restore the overall limb alignment. There are limited short-term studies published from Indian hospitals that investigated the importance of neutral mechanical component alignment in TKA patients. Methods: Retrospective and prospective study was conducted at the Department of orthopaedics, Sancheti Institute for Orthopaedics and Rehabilitation, Pune from June 2020 to September 2022. Enrolled patients were assessed preoperatively and postoperatively using clinical examination, radiological assessment and functional outcomes through the Oxford knee score, Knee society score and VAS score. Results: 204 patients enrolled, and 267 knees were evaluated for the study. Osteoarthritis was the commonest diagnosis (254 knees, 95.13%). Pre-operatively, 92.13% knees were varus, 4.87% valgus and 3% neutral while post-operatively, 51.69% were varus, 16.1% were valgus, and 32.32% were with neutral axis. Majority of patients with a pre-operative neutral axis converted to varus axis (62.5%), while most valgus axis cases preoperatively converted to a neutral axis (53.84%). For pre-operative varus subgroup, the majority patients with < 10° pre-operative axis converted to neutral (41.28%). Majority patients with 10°-20° pre-operative axis remained varus (60.53%) and with > 20° pre-operative axis remained varus (78.26%). Functional outcome parameters were significantly improved at follow-up (P < 0.05). Conclusion: Short-term postoperative functional scores were significantly improved in postoperative cases, with the postoperative alignment of 0° ± 3° relative to the mechanical axis was achieved. Thus, postoperative neutral mechanical alignment of 0° ± 3° can be the standard of care for patients undergoing TKA.

Effects of three-dimensional femur and tibia postures on the parameters of standing long-leg radiographs for osteoarthritic knees in elderly female subjects.

BACKGROUND: Long-leg frontal radiographs of the lower extremities are used to assess knee osteoarthritis. Given the three-dimensional (3D) nature of alignment changes in osteoarthritis, postural alterations in the femur and tibia extend beyond the coronal plane (in-plane) to include the transverse and sagittal planes (out-of-plane). This study investigates the impact of these out-of-plane factors on in-plane knee alignment parameters observed in frontal radiographs. METHODS: A total of 97 osteoarthritic knees in women were examined. Using a 3D-to-two-dimensional (2D) image matching technique, we evaluated the 3D postures of the femur and tibia in the standing position as viewed from frontal radiographs in the world coordinate system. Statistical analyses were conducted to explore associations between these 3D postures and 2D alignment parameters obtained from frontal radiographs under identical conditions. FINDINGS: The femur exhibited a medial inclination of 2.7°, a posterior inclination of 3.9°, and an internal rotation of 4.2°, whereas the tibia showed a lateral inclination of 6.4°, an anterior inclination of 6.7°, and an internal rotation of 6.7°. Both coronal and rotational postures of femur and tibia influenced the hip-knee-ankle angle, mechanical axis percentage, and medial proximal tibial angle. However, only coronal factors of tibia impacted tibial joint line obliquity relative to the floor. INTERPRETATION: Attention should be paid to the potential impact of the out-of-plane postures of the femur and tibia on parameters assessed in plain frontal radiographs of the lower extremities.

Factors Associated with Postoperative Knee Joint Line Obliquity After Medial Open Wedge High Tibial Osteotomy.

BACKGROUND: There are still few reports on factors associated with postoperative knee joint line obliquity (KJLO). PURPOSE: The purpose was to determine preoperative radiographic factors that are associated with KJLO postoperatively after open wedge high tibial osteotomy (OWHTO) using multivariable linear regression analysis and multivariable logistic regression analysis. STUDY DESIGN: Case-control study; Level of evidence, 3. METHODS: A total of 60 patients with 65 varus knees who underwent OWHTO between December 2012 and June 2018 at a single institution were retrospectively enrolled in this study. The authors evaluated radiologic parameters including the weightbearing line ratio, femorotibial angle, medial proximal tibial angle, mechanical lateral distal femoral angle (LDFA), lateral distal tibial angle, joint line convergence angle (JLCA), KJLO, and ankle joint obliquity. They also categorized these radiographic parameters as preoperative and postoperative and calculated the difference (Δ) between preoperative and postoperative values. To determine which of the radiographic parameters were most associated with postoperative KJLO, multivariable linear regression analysis was performed using the stepwise method. Multivariable logistic regression analysis was used to examine the relative contribution of the preoperative radiographic parameters to an abnormal postoperative KJLO (>4°). RESULTS: In the multivariable linear regression analysis, the preoperative LDFA and JLCA showed a statistically significant correlation. Multivariable logistic regression analysis revealed that the mean preoperative LDFA was significantly larger in the group with abnormal KJLO than in the group with the control group (odds ratio, 1.84; 95% CI, 1.12-3.02; P = .02), while preoperative JLCA tended to be larger in the abnormal KJLO group than the control group but not statistically significantly different. CONCLUSION: KJLO after OWHTO was associated with preoperative LDFA and JLCA in multivariable linear regression analysis, and preoperative LDFA was the most important factor associated with abnormal KJLO after OWHTO in multivariable logistic regression analysis.

The Presence of Cartilage Affects Femoral Rotational Alignment in Total Knee Arthroplasty.

OBJECTIVE: To assess the difference between the posterior condylar angle (PCA) and the mechanical lateral distal femoral angle (mLDFA) in the osseous and cartilaginous contours in a non-arthritic Chinese population. METHODS: Computed tomography (CT) and magnetic resonance imaging (MRI) were obtained from 83 patients with knee injuries before arthroscopy, and femur and distal femoral cartilage three-dimensional (3D) models were constructed. The 3D cartilage model was arranged to share physical space with the 3D femoral model, and then PCA and mLDFA were measured on the osseous and cartilaginous contours, respectively. The differences between the measurements with and without cartilage were evaluated. RESULTS: The average PCA with cartilage was 2.88 ± 1.35° and without was 2.73 ± 1.34°. The difference was significant in all patients and females but not in males. The average mLDFA with cartilage was 84.73 ± 2.15° and without cartilage was 84.83 ± 2.26°, but the difference was statistically insignificant in all groups. CONCLUSION: PCA on the osseous and cartilaginous contours significantly differed with and without cartilage in the female group, suggesting that cartilage thickness should be considered during preoperative femoral rotational resection planning.

Wedge-less oblique supracondylar femoral osteotomy and casting for genu valgum in older children and young adults.

BACKGROUND: Genu valgum is one of the commonest deformities seen by the orthopaedicians. The most common cause is idiopathic but genu valgum secondary to nutritional deficiency is also fairly common in developing and third world countries. Supracondylar osteotomy and internal fixation with plate and screws, is the treatment of choice in older children and young adults, which is costly, requires a wide exposure, a second surgery for implant removal and risk of infection is more. This study was undertaken to measure the outcome of simple oblique percutaneous wedge-less metaphyseal supracondylar osteotomy of the distal femur and casting in older children and adolescents with Genu Valgum in a small centre catering mostly to patients from middle and low income households. PATIENTS AND METHODS: Patients aged between 12 and 22 years with genu valgum deformity with a tibiofemoral angle ≥15°, and an intermalleolar distance of more than 7 cm in unilateral and more than 10 cm in bilateral cases, who are not amenable to be treated with guided growth techniques, were included. Patients having knee instability, restriction of knee range of motion, genu recurvatum, tibial deformity component, open physis, were excluded from the study. The correction was undertaken by a simple supracondylar wedge-less metaphyseal short oblique osteotomy of the distal femur followed by immobilization with a long leg plaster of Paris cast. Functional outcome was assessed using Böstman et al. score. RESULTS: 46 limbs in 29 patients with a mean age of 14.5 years were operated. The mean follow-up of patients was 6 months. The preoperative radiological tibiofemoral angle (TFA) had a mean value of 19.89° which improved to a mean of 5.31° postoperatively. Intermalleolar distance (IMD) improved from a mean of 13.81 cm to 3.15 cm post-correction. Mean Lateral distal femoral angle (LDFA) improved from 77.11° to 87.20°. Knee score was excellent in all patients at 3 months and 6 months post intervention. There were no serious complications except superficial plaster sores in 4 patients, which healed uneventfully and temporary restriction of knee range of motion in 5 patients. All patients achieved a full range of knee motion after physical therapy. CONCLUSION: Supracondylar wedge-less short oblique metaphyseal distal femoral osteotomy and immobilization with plaster of Paris cast is a simple, cheap, safe & viable option for the correction of genu valgum deformity originating from distal femur, with minimal complications in older children and adolescents with limited growth potential, especially in low income countries and small centres.

Validation and modification of the Coronal Plane Alignment of the Knee classification in the Asian population.

AIMS: The Coronal Plane Alignment of the Knee (CPAK) classification is a simple and comprehensive system for predicting pre-arthritic knee alignment. However, when the CPAK classification is applied in the Asian population, which is characterized by more varus and wider distribution in lower limb alignment, modifications in the boundaries of arithmetic hip-knee-ankle angle (aHKA) and joint line obliquity (JLO) should be considered. The purposes of this study were as follows: first, to propose a modified CPAK classification based on the actual joint line obliquity (aJLO) and wider range of aHKA in the Asian population; second, to test this classification in a cohort of Asians with healthy knees; third, to propose individualized alignment targets for different CPAK types in kinematically aligned (KA) total knee arthroplasty (TKA). METHODS: The CPAK classification was modified by changing the neutral boundaries of aHKA to 0° ± 3° and using aJLO as a new variable. Radiological analysis of 214 healthy knees in 214 Asian individuals was used to assess the distribution and mean value of alignment angles of each phenotype among different classifications based on the coronal plane. Individualized alignment targets were set according to the mean lateral distal femoral angle (LDFA) and medial proximal tibial angle (MPTA) of different knee types. RESULTS: A very high concentration, 191 from 214 individuals (89.3%), were found in knee types with apex distal JLO when the CPAK classification was applied in the Asian population. By using aJLO as a new variable, the high distribution percentage in knee types with apex distal JLO decreased to 125 from 214 individuals (58.4%). The most common types in order were Type II (n = 70; 32.7%), Type V (n = 55; 25.7%), and Type I (n = 46; 21.5%) in the modified CPAK classification. CONCLUSION: The modified CPAK classification corrected the uneven distribution when applying the CPAK classification in the Asian population. Setting individualized TKA alignment targets according to CPAK type may be a practical method to recreate optimal LDFA and MPTA in KA-TKA. Cite this article: Bone Jt Open 2022;3(3):211-217.

Tibiofemoral dynamic stressed gap laxities correlate with compartment load measurements in robotic arm-assisted total knee arthroplasty.

AIMS: It is unknown whether gap laxities measured in robotic arm-assisted total knee arthroplasty (TKA) correlate to load sensor measurements. The aim of this study was to determine whether symmetry of the maximum medial and lateral gaps in extension and flexion was predictive of knee balance in extension and flexion respectively using different maximum thresholds of intercompartmental load difference (ICLD) to define balance. METHODS: A prospective cohort study of 165 patients undergoing functionally-aligned TKA was performed (176 TKAs). With trial components in situ, medial and lateral extension and flexion gaps were measured using robotic navigation while applying valgus and varus forces. The ICLD between medial and lateral compartments was measured in extension and flexion with the load sensor. The null hypothesis was that stressed gap symmetry would not correlate directly with sensor-defined soft tissue balance. RESULTS: In TKAs with a stressed medial-lateral gap difference of ≤1 mm, 147 (89%) had an ICLD of ≤15 lb in extension, and 112 (84%) had an ICLD of ≤ 15 lb in flexion; 157 (95%) had an ICLD ≤ 30 lb in extension, and 126 (94%) had an ICLD ≤ 30 lb in flexion; and 165 (100%) had an ICLD ≤ 60 lb in extension, and 133 (99%) had an ICLD ≤ 60 lb in flexion. With a 0 mm difference between the medial and lateral stressed gaps, 103 (91%) of TKA had an ICLD ≤ 15 lb in extension, decreasing to 155 (88%) when the difference between the medial and lateral stressed extension gaps increased to ± 3 mm. In flexion, 47 (77%) had an ICLD ≤ 15 lb with a medial-lateral gap difference of 0 mm, increasing to 147 (84%) at ± 3 mm. CONCLUSION: This study found a strong relationship between intercompartmental loads and gap symmetry in extension and flexion measured with prostheses in situ. The results suggest that ICLD and medial-lateral gap difference provide similar assessment of soft-tissue balance in robotic arm-assisted TKA. Cite this article: Bone Jt Open 2021;2(11):974-980.

Is Bony Knee Alignment Representative of the True Joint Surface in Skeletally Immature Patients? A Magnetic Resonance Imaging Study.

AIM AND OBJECTIVE: In deformity correction around the knee, the mechanical lateral distal femoral angle (mLDFA) and medial proximal tibial angle (MPTA) are used in surgical planning routinely. While plain radiographs are generally adequate, some surgeons utilise intraoperative arthrograms to visualise the articular contours and assess a younger child's true joint alignment, often with findings that these are discrepant from that measured just using bone alignment. The age cutoff for a discrepancy between the two is not defined. MATERIALS AND METHODS: We queried our picture archiving and communication systems (PACS) database for MRIs with a radiological read of "normal" for patients between the ages of 4 and 16 years at the time of the study. Anatomic axes were used to determine the anatomic LDFA (aLDFA) and MPTA angles using end-cartilage and end-bone landmarks independently. RESULTS: We reviewed 116 MRIs, 56% male, with approximately 9 studies per year of age. There were no significant overall differences between aLDFA and MPTA when measured at the bone vs cartilage surfaces (p = 0.42 and p = 0.53, respectively). In the 4- to 6-year age range, there was a significant difference between bony and cartilaginous aLDFA (p = 0.02) but not MPTA (p = 0.88). CONCLUSION: In children 6 years of age and younger, intraoperative arthrogram should be considered while treating knee deformity, as plain films may not fully represent the true deformity of the distal femur in particular. CLINICAL SIGNIFICANCE: Supports the need for advanced imaging or intraoperative arthrogram for joint corrective surgery in young patients. LEVEL OF EVIDENCE: Level 3 diagnostic. HOW TO CITE THIS ARTICLE: Bigach SD, Carender CN, Liu RW. Is Bony Knee Alignment Representative of the True Joint Surface in Skeletally Immature Patients? A Magnetic Resonance Imaging Study. Strategies Trauma Limb Reconstr 2020;15(2):79-83.

Advantages of the experience of navigation when starting manual total knee arthroplasty.

PURPOSE: To evaluate how the accuracy of coronal-plane bone cutting and operative time may be affected by the experience of navigated total knee replacement (TKR) in starters of manual TKR. METHODS: We analyzed 30 cases of navigated TKR performed in the early years (group 1), 30 consecutive cases of navigated TKR performed after experiencing more than 100 cases of navigated TKR (group 2), and the initial 30 consecutive cases of manual TKR (group 3). Postoperative mechanical hip-knee-ankle (mHKA) angle, mechanical medial proximal tibial angle (mMPTA), and mechanical lateral distal femoral angle (mLDFA) were measured. Bone cutting was aimed at mHKA angle of 0°, mMPTA of 90°, and mLDFA of 90°. We have set the tolerance of absolute value of errors in mHKA angle, mMPTA and mLDFA as 0 ± 3°. Comparative analysis of tourniquet times have been performed. RESULTS: Postoperative absolute error values of mHKA angle, mMPTA, and mLDFA were 2.78 ± 3.53°, 1.06 ± 1.91°, and 1.44 ± 1.90° in group 1; 1.18 ± 1.32°, 1.20 ± 1.49°, and 0.98 ± 1.09° in group 2; and 2.11 ± 2.49°, 1.35 ± 0.62°, and 1.92 ± 2.85° in group 3. Tourniquet times were 67.50 ± 21.50 min in group 1, while group 2 and group 3 showed tourniquet times of 51.87 ± 12.00 and 52.00 ± 15.00 min, respectively. CONCLUSION: In starters of manual TKR, previous experience of performing navigated TKR may help the error values during femoral and tibial bone cutting to fall within the values similar to the median error value of navigated TKR. It may also help to reduce the operative time of manual TKR similar to the operative time of and experienced surgeon with over 100 cases of navigated TKR.

Lower extremity alignment due to patellofemoral syndrome and dynamic postural balance.

STUDY DESIGN: This study is a prospective study. AIM: Lower extremity malalignment is an important etiologic factor in patellofemoral pain syndrome (PFPS). We hypothesized that lower limb malalignment may affect dynamic balance and physical function. This prospective study was conducted to investigate the relationship between the lower limb alignment and the dynamic balance and physical function in patients with PFPS. METHODS: The study included 62 individuals with unilateral PFPS. Pain severity was assessed by the numerical pain scale and the pain duration was recorded. Lower extremity bone alignment was evaluated by the lateral distal femoral angle (LDFA) and the medial proximal tibia angle. Dynamic postural balance was assessed by the star excursion balance test. The functional status of the patients was evaluated by the 30-second chair stand test. RESULTS: The mean duration of the pain was 24.2 ± 31.5 months and the mean pain severity was 8.1 ± 1.4. Although there was a significant difference found between the affected and unaffected LDFA values of lower extremities (p < 0.05), there was no difference found with regard to the dynamic balance values of the lower extremities (p > 0.05). However, significant changes of posterolateral balance were identified at a painful side without causing a postural dynamic imbalance (p < 0.05). CONCLUSION: In our study, we found a valgus deformity as a deterioration in the lower limb alignment of patients with PFPS which may cause a deterioration of posterolateral balance only. However, no change in postural dynamic balance was observed in the comparison of affected side and unaffected side. Dynamic postural balance has been influenced by many kinematic changes related to lower extremities including pelvis, hip, and ankle. Thus, reciprocal mechanisms in the anatomical structures may compensate the postural balance dynamically.