Search Results (12)

Background: Osteotomies around the knee aim to correct varus or valgus malalignment and improve biomechanics. However, little is known about their effect on knee phenotypes, as defined by the Coronal-Plane-Alignment-of-the-Knee (CPAK) and Hirschmann’s functional classification. This study evaluated pre- and postoperative phenotypes in patients undergoing high-tibial-osteotomy (HTO) or distal-femoral-osteotomy (DFO). Methods: We retrospectively analysed 214 osteotomies around the knee (HTO: 145; DFO: 69) of 188 patients from our institutional registry. Radiographic parameters were measured using a validated artificial intelligence software, with phenotypes classified by CPAK and Hirschmann classification. Preoperative osteotomy planning was compared to postoperative alignment. Regression was used to assess the influence of demographic and radiographic factors. Results: CPAK types changed in 95.3% of cases. Medial opening HTOs most frequently shifted from CPAK type I (73.8%) to VI (42.3%), while medial closing DFOs transitioned from type III (81.5%) to V (24.1%). Concordance between planned and achieved CPAK types was highest for types III, IV, and V. Postoperative angles were generally smaller than planned for joint-line-obliquity (JLO), lateral-distal-femur-angle, and medial-proximal-tibial-angle (p < 0.001). Neutral JLO was restored in only 48.1%. Preoperative phenotypes NEUmLDFA0° (40.1%) and VARmMPTA3° (32.3%) were most common, while postoperative phenotypes included VALmLDFA3° (52.4%) and VALmMPTA3° (37.7%). Age, sex, and BMI significantly influenced alignment outcomes. Conclusions: Postoperative CPAK classifications shifted significantly across all osteotomy types, with minimal retention of preoperative types. Although most procedures achieved correction within the target HKA range, restoration of a neutral JLO was observed in only half of the cases, emphasizing the importance of phenotype-specific planning and highlight potential limitations of CPAK classification. Full article

Micro-computed tomography assessment of osteochondral microstructural properties of the distal femur and proximal tibia was comprehensively conducted to compare adult patients with knee rheumatoid arthritis (RA) and primary knee osteoarthritis (KOA), with special focus on the effects of knee malalignment. This study encompassed 402 bone samples divided into three groups: the RA group [patients who were subjected to total knee arthroplasty (TKA) due to RA, n = 23, age: 61 ± 10 years], the KOA group [individuals subjected to TKA due to KOA, n = 24, age: 71 ± 9 years] and the control group [sex-matched cadavers without degenerative knee diseases, n = 20, age: 67 ± 11 years]. Our data revealed that the RA, KOA, and control groups differ significantly in osteochondral microstructural properties depending on the knee alignment. Specifically, increasing femoral and tibial cortical porosity, coupled with thinner articular cartilage, were noted in the RA and KOA groups, compared to the controls. Furthermore, larger femoral and tibial cortical pores, lower tibial and femoral subchondral trabecular bone fraction, and thinner tibial articular cartilage were noted in the RA group in comparison to the KOA group, implying that the medial-to-lateral load distribution in the knee joint could be most affected in these patients. Our data illustrated that the thinnest cartilage, a thicker and less porous cortex, along with lower trabecular bone volume, were present in the lateral femoral and tibial condyles of RA individuals with valgus knee alignment. Observed subchondral trabecular microarchitectural alterations could be morphological factors contributing to different effects of surgical treatment and variable implant stability in individuals with RA, warranting further research. Full article

Background/Objectives: Total knee arthroplasty (TKA) is the gold-standard treatment for advanced knee arthritis, offering pain relief and improved joint function. However, tibial component malalignment, malrotation, and improper biomechanical loading remain critical factors contributing to implant failure, instability, and revision surgeries. This review systematically examines the impact of biomechanical loading on the tibial insert following primary TKA, with a focus on alignment, posterior tibial slope (PTS), and load distribution. Methods: A systematic literature search was conducted across the PubMed, Google Scholar, and Web of Science databases following the PRISMA guidelines. Studies investigating the effects of tibial component alignment, varus/valgus deviations, PTS, and load distribution on tibial inserts post-TKA were included. Seven studies meeting the inclusion criteria were analyzed and described narratively. Results: The reviewed studies highlighted that varus and valgus malalignment significantly alter tibiofemoral contact pressures and ligament strains, increasing the risk of aseptic loosening and implant failure. Excessive PTS was associated with posterior femoral translation, altered ligament tension, and increased contact stresses on polyethylene (PE) inserts. Kinematically aligned TKA demonstrated reduced tibial force imbalances and improved functional outcomes compared to mechanically aligned TKA. Computational and cadaveric studies revealed that even minor malalignments (e.g., 3° varus or valgus) can cause significant biomechanical changes. Conclusions: Biomechanical loading on tibial inserts after primary TKA is highly sensitive to the alignment and PTS. Optimal alignment and controlled biomechanical forces are essential. Kinematically aligned TKA has shown promising effects, preventing aseptic loosening and ensuring long-term implant survival. Further in vivo studies are needed to validate these findings and optimize surgical techniques. Full article

Background/Objectives: In patients with varus knee osteoarthritis, compensatory changes occur in the foot and ankle joints to compensate for the varus deformity of the knee. The aim of the study was to investigate the changes in the ankle of patients whose knee alignment was corrected with total knee arthroplasty (TKA) and to explore the clinical implications of these findings. Methods: In this retrospective observational study, we analyzed 204 knees of 179 patients who had regular follow-ups out of 431 patients who underwent TKA for varus knee osteoarthritis between January 2019 and July 2021. Patient demographics, body mass index, follow-up time, and radiographs were studied. The hip–knee–ankle (HKA) angle, joint line convergence angle (JLCA), talar tilt (TT) angle, ground talar dome (GT) angle, ground tibia plafond (GP) angle, and the American Orthopaedic Foot & Ankle Society (AOFAS) score were assessed preoperatively and at the last follow-up. Results: A total of 204 knees of 179 patients with a mean follow-up time of 32.50 ± 6.68 months were evaluated. It was found that the change in the HKA had a positive effect on the AOFAS score and a negative effect on the TT, GT, and GP angles. While the clinical score improved in 82 patients, it worsened in 8 patients. The age difference between the groups whose AOFAS score improved and worsened was statistically significant. Conclusions: The correction of the varus malalignment in the knee was shown to also improve the compensatory valgus in the foot and ankle over the mid-term, with a statistically significant improvement in the patients’ clinical ankle scores. Full article

Background: Total hip arthroplasty (THA) affects the biomechanics of the hip and the patient gait. The stem design influences femoral lever ratios and tissue trauma. Biomechanical changes such as these have the potential to induce knee arthritis. A varus or valgus configuration of knee arthritis is formed by asymmetric loadings. The aim of this study was to evaluate the impact of stem design in THA on knee valgus by comparing a standard implant with an implant with a short stem. Methods: A total of 2953 patients who underwent primary total knee arthroplasty for end-stage osteoarthritis between 2015 and 2021 were included in this retrospective data analysis. Patients were divided into three groups, depending on hip status (straight stem, short stem, and native joint). Leg alignment was distinguished as varus or valgus, and the degree of axial deviation was measured. Descriptive and explorative statistical analyses were performed, with a p value < 0.05 set as significant. Results: Ipsilateral knee valgus occurred significantly more often in patients with straight stems (57.2%) than in those with short stems (29%) and native joints (25.8%) (p < 0.001). Additionally, mean valgus deviation was significantly increased in patients with straight stems (8.9°) compared to those with short stems (6.4°) or native hip joints (6.7°). Both findings were accentuated in women. Conclusions: Previous ipsilateral straight-stem THA is associated with knee valgus deformity, especially in women. Short-stem THA seems to be better suited to restoring physiological biomechanics and preventing the development of valgus osteoarthritis of the ipsilateral knee. Full article

Little is known about the impact of the impaired limb on the uninvolved side, which might influence the overall functional outcome in individuals with unilateral cerebral palsy (CP). The objective of this work was to perform an assessment considering the kinematics/joint moments and ground reaction forces (GRFs). Eighty-nine individuals with unilateral CP were included and classified according to their functional impairment. Level-specific differences according to the Gross Motor Function Classification System (GMFCS), including pelvic and trunk movements, were analyzed using instrumented 3D gait analysis (IGA). Anterior trunk and pelvic tilt, trunk lean/pelvic obliquity, pelvic internal rotation, hip adduction, and external hip rotation, as well as pronounced flexion (ankle dorsiflexion), at all joint levels were significant kinematic alterations. Concerning joint moments, the most remarkable alterations were hip and ankle flexion, hip abduction, knee varus/valgus, and transversal joint moments at all levels (external rotation moments in particular). The most remarkable differences between GMFCS levels were at proximal segments. The kinematics and joint moments of the sound limb in patients with unilateral CP differ significantly from those of healthy individuals—partially concomitant to those of the involved side or as motor strategies to compensate for transversal malalignment and leg-length discrepancies (LLDs). GRF showed almost identical patterns between GMFCS levels I and II, indicating an unloading of the involved limb. Compensatory motor strategies of the sound limb do not influence functional outcomes. Full article

The correction of valgus leg malalignment in children using implant-mediated growth guidance is widely used and effective. Despite the minimal invasive character of the procedure, a relevant number of patients sustain prolonged pain and limited mobility after temporary hemiepiphysiodesis. Our aim was to investigate implant-associated risk factors (such as implant position and screw angulation), surgical- or anesthesia-related risk factors (such as type of anesthesia, use, and duration), and pressure of tourniquet or duration of surgery for these complications. Thirty-four skeletally immature patients with idiopathic valgus deformities undergoing hemiepiphysiodesis plating from October 2018–July 2022 were enrolled in this retrospective study. Participants were divided into groups with and without prolonged complications (persistent pain, limited mobility of the operated knee between five weeks and six months) after surgery. Twenty-two patients (65%) had no notable complications, while twelve patients (35%) had prolonged complications. Both groups differed significantly in plate position relative to physis (p = 0.049). In addition, both groups showed significant differences in the distribution of implant location (p = 0.016). Group 1 had a shorter duration of surgery than group 2 (32 min vs. 38 min, p = 0.032) and a lower tourniquet pressure (250 mmHg vs. 270 mmHg, p = 0.019). In conclusion, simultaneous plate implantation at the femur and tibia and metaphyseal plate positioning resulted in prolonged pain and a delay of function. In addition, the amplitude of tourniquet pressure or duration of surgery could play a factor. Full article

(1) Background: Optimal neuromuscular, Lumbo-Pelvic-Hip Complex, and lower extremity control are associated with decreased risk factors for secondary anterior cruciate ligament (ACL) injury. This study aimed to analyze any asymmetries and malalignments in the Lumbo-Pelvic-Hip Complex and the lower limbs at 6 months after ACL reconstruction (ACLR). (2) Methods: We conducted an exploratory retrospective observational single-center study in patients during the outpatient postoperative rehabilitation program at ICOT (Latina, Italy). From January 2014 to June 2020, 181 patients were recruited, but only 100 patients (86 male 28 ± 0.6 years, 178 ± 0.5 height; 14 female 24 ± 2.0 years, 178 ± 3.0 height) were eligible for the inclusion criteria and studied 6 months after ACL reconstruction surgery. (3) Statistical analysis: Student’s t-tests and Pearson’s product-moment correlation coefficient were used to determine significant differences between affected and non-affected limbs and variables’ association. (4) Results: The study shows a decrease in neuromuscular control of the Lumbo-Pelvic-Hip Complex and dynamic adaptive valgus of the knee at 6 months after ACLR (mean difference between pathological and healthy limb of dynamic adaptive valgus was −10.11 ± 8.19° 95% CI −14.84 to −9.34; mean value was 16.3 ± 6.8° 95% CI 14.04 to 18.55 for healthy limb and 4.2 ± 3.1° 95% CI 3.15 to 5.21 for pathological limb, p < 0.0001). The results also showed a relationship between dynamic adaptive valgus and contralateral pelvic drop (r = 0.78, 95% CI 0.62 to 0.88, magnitude of correlation very large). (5) Conclusions: The analysis showed an associative correlation between decreased postural control of the pelvic girdle and dynamic adaptive valgus of the knee in 38% of patients; this study highlights the usefulness of the Single-Leg Squat Test (SLST) as a clinical/functional assessment to evaluate the rehabilitation process and as a preventive tool to reduce the risk of second ACL injuries during the return to sport. Full article

Treating lower extremity malalignment-related knee osteoarthritis, especially valgus alignment, is a challenge. A high revision rate was observed with patients who underwent unicompartmental knee arthroplasty, so distal femur osteotomy has regained its popularity. This research aimed to evaluate the radiographic and functional outcomes of arthroscopy-assisted lateral open-wedge distal femur osteotomy (LOWDFO) for patients with lateral compartment osteoarthritis and valgus knees with a minimum follow-up of 2 years. Our study retrospectively included isolated lateral osteoarthritis (Outerbridge grade 3 and grade 4) of the knee related to valgus alignment and a young age (<65 y/o) with the demand for a high-impact activity event. Preoperative and postoperative radiographic and functional outcomes were evaluated. Significant pre-operative and postoperative mechanical correction was observed with mechanical axis deviation (preop/postop: −28.77 ± 12.98/−9.45 ± 7.36, p < 0.001), hip-knee angle (preop/postop: 7.64 ± 3.62/2.68 ± 2.04, p < 0.001), and mechanical lateral distal femoral angle (mLDFA, preop/postop: 10.9 ± 4.14/5.66 ± 3.71, p < 0.001). The International Knee Documentation Committee (IKDC) score also showed improvement after the operation (preop/postop: 57.36 ± 11.98/79.02 ± 4.58, p = 0.002). In conclusion, lateral open-wedge distal femur osteotomy is effective in treating patients with lateral compartment osteoarthritis and valgus knees with a low complication rate and excellent outcome. Full article

Background and objectives: Treatment of a displaced or comminuted periprosthetic distal femur fracture is challenging, especially in patients with osteoporosis. In this case report, we shared our successful surgical experience of using a long intramedullary fibula bone graft in a plate fixation surgery for a periprosthetic distal femur fracture in an extremely elderly patient with osteoporosis. Case report: A 95-year-old woman with severe osteoporosis (bone mineral density level: −3.0) presented with right knee pain and deformity after a fall, and a right periprosthetic distal femur fracture was identified. The patient underwent an open reduction and an internal plate fixation surgery with the application of a long intramedullary fibular bone graft. Due to a solid fixation, immediate weight-bearing was allowed after the surgery. She could walk independently without any valgus or varus malalignment or shortening 3 months after the surgery. A solid union was achieved 4 months postoperatively. Conclusions: We present a case wherein a long intramedullary allogenous fibula strut bone graft was used successfully to treat a right periprosthetic femur fracture in an extremely elderly patient. A long allogenous fibula bone graft can act not only as a firm structure for bridging the bone defect but also as a guide for precise component alignment. We believe this treatment option for periprosthetic fractures is beneficial for achieving biological and mechanical stability and facilitates early mobilization and weight-bearing for the patient. Full article

High tibial osteotomy (HTO) represents a sensible treatment option for patients with moderate unicondylar osteoarthritis of the knee and extraarticular malalignment. The possibility of a continuously variable correction setting and a surgical approach low in complications has meant that the medial opening osteotomy has prevailed over the past decades. The objective of the present study was to determine whether anteromedially positioned small plates are nevertheless forgiving under biomechanically unfavourable conditions (overcorrection and lateral hinge fracture). In this study, a simulated HTO was performed on composite tibiae with a 10-mm wedge and fixed-angle anteromedial osteosynthesis with a small implant. Force was applied axially in a neutral mechanical axis, a slight and a marked overcorrection into valgus, with and without a lateral hinge fracture in each case. At the same time, a physiological gait with a dual-peak force profile and a peak load of 2.4 kN was simulated. Interfragmentary motion and rigidity were determined. The rigidity of the osteosynthesis increased over the cycles investigated. A slight overcorrection into valgus led to the lowest interfragmentary motion, compared with pronounced valgisation and neutral alignment. A lateral hinge fracture led to a significant decrease in rigidity and increase in interfragmentary motion. However, in no case was the limit of 1 mm interfragmentary motion critical for osteotomy healing exceeded. The degree of correction of the leg axis, and the presence of a lateral hinge fracture, have an influence on rigidity and interfragmentary motion. From a mechanically neutral axis ranging up to pronounced overcorrection, the implant investigated offers sufficient stability to allow healing of the osteotomy, even if a lateral hinge fracture is present. Full article

This study investigated the differences in ankle alignment changes after TKA in patients with varying preexisting ankle deformities. We retrospectively examined 90 knees with osteoarthritis and varus deformity in 78 patients who underwent TKA. Preoperative and postoperative radiographic parameters were analyzed. According to their preexisting ankle deformity, patients were assigned to the valgus or varus group. Overall, 14 (15.6%) cases were of preoperative valgus ankle deformity; the remainder were of preoperative varus ankle deformity. Hip–knee–ankle angle (HKA), tibial plafond–ground angle (PGA), and talus–ground angle (TGA) all exhibited significant correction in both groups; however, tibial plafond–talus angle (PTA) and superior space of ankle joint (SS) only changed in the varus group. The median PTA and SS significantly decreased from 1.2° to 0.3° (p < 0.001) and increased from 2.5 to 2.6 mm (p = 0.013), respectively. Notably, ∆PTA positively correlated with ∆HKA in the varus group (r = 0.247, p = 0.032) but not in the valgus group. Between-group differences in postoperative PTA (p < 0.001) and ∆PTA (p < 0.001) were significant. The degree of ankle alignment correction after TKA differed between patients with preexisting varus and valgus ankle deformities. TKA could not effectively correct the preexisting ankle valgus malalignment. Full article