Residual Varus Research Articles

A finite element analysis of patellofemoral joint biomechanics: Exploring potential causes of postoperative anterior knee pain following unicompartmental knee arthroplasty

PurposeAnterior knee pain is a common complication following unicompartmental knee arthroplasty (UKA). This study aimed to elucidate the mechanism of anterior knee pain after UKA by examining the biomechanical characteristics of the patellofemoral joint. MethodsThis study employs the finite element analysis method. A healthy model of the right lower limb was created using CT scans of an intact right lower limb from a healthy woman. Based on this model, a preoperative pathological model was generated by removing the meniscus and part of the articular cartilage. The UKA prosthesis was then applied to this model with five different bearing thicknesses: 5 mm, 7 mm, 10 mm, 11 mm, and 13 mm. To simulate various degrees of knee joint flexion, the femur was rotated relative to the knee joint's rotational axis, producing lower limb models at flexion angles of 0°, 30°, 60°, 90°, and 120°. We applied a constant force from the center of the femoral head to the center of the ankle joint to simulate lower limb loading during squatting. The simulations were conducted using Ansys 17.0. ResultsBoth overstuffing and understuffing increased the peak stress on the patellar cartilage, with overstuffing having a more pronounced effect. Compared to healthy and balanced models, overstuffed and understuffed models exhibited abnormal stress distribution and stress concentration in the patellar cartilage during knee flexion. ConclusionOverstuffing and understuffing lead to residual varus or valgus deformities after UKA, causing mechanical abnormalities in the patellofemoral joint. These abnormalities, characterized by irregular stress distribution and excessive stress, result in cartilage damage, exacerbate wear in the patellofemoral joint and consequently lead to the occurrence of anterior knee pain.

Complications of revision knee arthroplasty

Due to the growing scale of arthroplasty and the widening of indications for knee joint replacement, the durability of joint functioning has become a critical issue. Untimely diagnosis and inadequate treatment of patients with endoprosthesis component loosening leads to major bone defects. This problem arises from repeated joint interventions, large bone defects and duration of revision surgeries, that is fraught with catastrophic consequences for patients – revision prosthesis removal or even limb amputation. The project aims to improve the treatment for patients with instability of components after knee joint arthroplasty. The aim of the study is to analyze the results of revision knee arthroplasty and identify the causes of mistakes and complications of revision arthroplasty with the intention of prevention. Materials and methods. A retrospective analysis of 50 revision knee arthroplasties performed at the Centre for Arthroplasty of the State Institution “Institute of Traumatology and Orthopedics of the National Academy of Medical Sciences of Ukraine” was conducted. Clinical and radiological findings were evaluated for all patients. All revision prostheses used in this study were of the semi-constrained type. Cementation technique was used for all implants. In the revision of the septic complication group, a full cementation technique with antibiotics according to a sensitivity profile were used, while in the aseptic complication group, a surface cementation technique with antibiotics according to sensitivities were used. Results. The authors of the project have analyzed the results of treatment of 50 revision arthroplasty procedures performed between 2013 and 2022 for instability of the endoprosthesis components. The structure of complications has been examined and the causes of failure in revision knee arthroplasty have been identified. This study has shown promise in preventing complications and developing personalized approaches to revision arthroplasty. Conclusions. The analysis of revision knee arthroplasty failure has shown the prevalence of septic complications (56.0 %). In the case of septic complications after revision arthroplasty, Staphylococcus aureus prevailed (57.1 %), gram (-) microorganisms were causative agents in other cases. Factors resulting in aseptic complications included those associated with the surgical intervention (81.8 %), the patient (45.4 %) and the combination thereof (72.7 %). Significant causes of the femoral revision component loosening were residual valgus deformity, medial instability in the frontal plane; significant causes of the tibial component loosening were residual varus deformity and lateral instability in the frontal plane.

Correlation between Component Size and Functional Knee Score in Patients Undergoing Bilateral Simultaneous Total Knee Arthroplasty: A Cross-Sectional Study

Abstract Background: Simultaneous bilateral total knee arthroplasty (simBTKA) has been a favored surgical solution to reduce costs and patient suffering. We aimed to evaluate the rate of asymmetry of component size in patients undergoing simBTKA and its impact on knee function as we believe that implant asymmetry may affect the functional outcomes in those patients. Methods: A cross-sectional study design was done on on 60 patients (120 knees) with simBTKA using patient-specific templating (PST). Patients were included if they had Kellgren–Lawrence Grade III-IV osteoarthritis. Revision surgeries, staged BTKA, or patients with bone defects, valgus deformity, severe varus deformity (defined as above 20°), and extra-articular deformities were excluded from the study. The outcome measures were interlimb component asymmetry, Knee Society Score (KSS), and range of motion (ROM). The comparison between pre- and postoperative findings was done using a dependent t-test. Results: A total of 29 (48.34%) patients had symmetrical femoral and tibial components, whereas the rest had asymmetry, of them, 11.7% had both femoral and tibial component size asymmetry. There were no statistically significant differences between the changes in KSS and ROM in the smaller implant and larger implant groups (P = 0.5 and P = 0.4, respectively). The total number of complications was eight and as follows: superficial infection, aseptic loosening, rupture of the patellar tendon after a bathroom fall, anemia requiring blood transfusion, residual varus deformity, deep venous thrombosis, periprosthetic fracture, and malalignment. Conclusion: There is no correlation between the interlimb component asymmetry and the knee function. However, there was statistically significant improvement from preoperative to postoperative KSS and ROM in small and large implants.

Return to Duty in Military Servicemembers After High Tibial Osteotomy Not Associated With Preoperative Radiographic Parameters : A Retrospective Analysis.

Evidence on return to sports/work after high tibial osteotomy (HTO) is limited, especially in a young, high-demand population. To (1) identify whether preoperative knee pathology or intraoperative correction was associated with successful return to duty (RTD) and (2) assess whether postoperative complications and reoperation were associated with failure to RTD. Case series; Level of Evidence, 4. We performed a retrospective cohort study of a consecutive series of patients in the Military Health System aged 18 to 55 years with medial compartment osteoarthritis who underwent HTO between 2003 and 2018. Concomitant meniscal and cartilage procedures were included, while cases with concomitant ligamentous procedures were excluded. The inclusion criteria were as follows: active-duty military status, minimum 2-year follow-up, preoperative knee radiographs, and pre- and postoperative long-leg alignment radiographs. Preoperative Kellgren-Lawrence grades and pre- and postoperative hip-knee-ankle angles were measured. The primary outcome was RTD. Failure was defined as knee-related medical separation from the military or conversion to total knee arthroplasty. The secondary outcome was reoperation. A total of 55 HTOs were performed in 50 patients who met the inclusion criteria, with a mean age of 39 years old (range, 22.8-55 years). The mean follow-up was 5 years (range, 2.1-10.7 years). Ten knees (18.2%) failed HTO (1 conversion to total knee arthroplasty, 9 medical separations), 15 additional knees (27.3%) had permanent activity restrictions, and 30 knees (54.5%) returned to duty without restrictions. Reoperation occurred in 36.4% of knees and was associated with medical separation (P = .039). Younger age was associated with medical separation (P = .003) and permanent restrictions (P = .006). Patients with a postoperative varus deformity of >5° were more likely to undergo medical separation (P = .023). In a young, high-demand population, HTO succeeded in returning 54.5% of knees to full duty without restriction despite 36.4% of knees requiring reoperation. Residual varus deformity or reoperation was associated with lower RTD rates. No association was identified between RTD and preoperative osteoarthritis grading or deformity.

Clubfoot Correction with Ponseti Technique: Three-Dimensional Alignment Analysis and Residual Adult Deformity Effects on Patient-Reported Outcomes

Introduction/Purpose: Few studies have assessed the long-term outcomes of the Ponseti technique and none have utilized 3- dimensional weightbearing analysis. The goal of this study was to understand how potential residual 3D deformities and abnormalities influence patient reported outcomes (PROs). This was accomplished by assessing anatomical foot and ankle alignment in adult clubfoot patients treated with the Ponseti method using 3D weightbearing CT (WBCT) imaging and then correlating residual foot and ankle malalignment with PROs. Methods: There were 37 consecutive patients (57 feet) included and 14 volunteers healthy controls (28 feet) included in this study. Every participant was evaluated using a WBCT (HiRise©) in a bipedal standing position. From these scans Cavus, Adductus, and Varus components were evaluated using multiple 3D measurements calculated using the semi-automatic segmentation software Bonelogic®. Specific Cavus related measurements included sagittal talus-first metatarsal angle and the calcaneal inclination angle. Varus related measurements included talocalcaneal angle in both the sagittal and axial planes as well as the hindfoot moment arm and the hindfoot alignment angle. Adductus deformity was evaluated using talonavicular coverage angle. These measurements were then correlated with patient reported outcome surveys, which included Visual Acuity Scale for pain, PROMIS general health, PROMIS physical function, PROMIS pain interference, pain catastrophic scale, and European foot and ankle society score. Results: There was no significant overall residual 3D-deformity observed in clubfoot patients when compared to controls, with similar FAO measurements observed between the groups, clubfoot=2.63% (95%CI=1.41%-3.85%) and control=3.2% (CI=1.6%- 4.8%,P=0.58). The sagittal talus-first-metatarsal in the clubfoot-patients had a mean-value of -0.12° compared to the controls, −5.2°. Clubfoot patients also had a decreased calcaneal-inclination-angle relative to the controls, 13.01° and 21.5° respectively. Talocalcaneal-angle for clubfoot patients in both the sagittal-plane,44.28°, and axial-plane, 17.74°, were reduced compared to the controls, 57.51° and 25.78°. Talonavicular-coverage-angle in the clubfoot-group (18.63°) was less than the controls (29.19°). Talus- first-metatarsal-angle in the sagittal-plane was significantly correlated with VAS-scores (RSquare=0.19,P=0.0118) and the EFAS- Score (RSquare=0.27,P=0.0025). Talocalcaneal-angle in the sagittal plane was also significantly correlated with the PROMIS-Pain- Interference-score (P=0.038) and PROMIS-Physical-Function-score (RSquare=0.32,P=0.0007). Conclusion: The Ponseti technique is an effective nonsurgical treatment for the overall three-dimensional foot and ankle alignment of Clubfoot. While mild, but statistically significant residual Varus and Adductus deformities were observed in adult clubfoot patients, the overall 3D alignment (FAO) was found to be similar between clubfoot patients and controls. These findings highlight the efficacy of the Ponseti technique and potentially explain the overall good PROs. The results of this study could potentially provide insight into treatment targets that may be applied to help optimize patient outcomes when treating children with Clubfoot in the future. The Ponseti technique is an effective nonsurgical treatment for Clubfoot's overall three-dimensional foot and ankle alignment. While mild, but statistically significant residual Varus and Adductus deformities were observed in adult clubfoot patients, the overall 3D alignment (FAO) was found to be similar between clubfoot patients and controls. These findings highlight the efficacy of the Ponseti technique and potentially explain the overall good PROs. The results of this study could potentially provide insight into treatment targets that may be applied to help optimize patient outcomes when treating children with Clubfoot in the future.

Comparison of Outcomes in Obese Patients after Total Knee Arthroplasty with Neutral or Mild Varus: A Retrospective Study with 8-Year Follow-Up.

Residual varus after total knee arthroplasty (TKA) can affect functional outcomes, which may worsen in the presence of obesity. However, no studies were found to compare the outcomes of obese patients involving postoperative residual mild varus or neutral. The aim of this study was to compare postoperative complications and prosthesis survival, and functional outcomes for knees of obese patients with neutral or mild varus after TKA. We retrospectively reviewed 188 consecutive obese patients (body mass index ≥30 kg/m2) at our hospital who underwent TKA due to varus knee osteoarthritis from January 2010 to December 2015. The mechanical hip-knee-ankle axis angle was measured in all patients at admission and discharge. Knee functions were retrospectively assessed based on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, Knee Society Knee Score (KS-KS), Knee Society Function Score (KS-FS), Forgotten Joint Score (FJS), and range of motion (ROM). Continuous data were compared between knees with neutral or mild varus alignment using analysis of Student's t test or variance or the Kruskal-Wallis test as appropriate. For multiple comparisons of outcomes, we used Bonferroni-Dunn method to adjust p-values. Categorical data were compared using the chi-squared test. Of the 156 knees in 137 obese patients who completed follow-up for a mean of 8.32 ± 1.47 years, 97 knees were corrected from varus to neutral and 54 knees were kept in mild residual varus. Patients with mild varus knees had significantly WOMAC (8.25 ± 8.637 vs. 14.97 ± 14.193, p = 0.009) and better FJS (86.03 ± 15.607 vs. 70.22 ± 30.031, p = 0.002). The two types of knees did not differ significantly in KS-KS, KS-FS, or ROM. Although one patient with a neutral knee had to undergo revision surgery, there was no significant difference between two groups. For obese patients with osteoarthritis, preservation of residual varus alignment after TKA can improve functional outcomes without compromising prosthesis survival.

Peroneus Brevis to Longus Tendon Transfer in the Treatment of Flexible Progressive Collapsing Foot Deformity: A Cadaveric Study.

Although operative treatment of the flexible progressive collapsing foot deformity (PCFD) remains controversial, correction of residual forefoot varus and stabilization of the medial column are important components of reconstruction. A peroneus brevis (PB) to peroneus longus (PL) tendon transfer has been proposed to address these deformities. The aim of our study was to determine the effect of an isolated PB-to-PL transfer on medial column kinematics and plantar pressures in a simulated PCFD (sPCFD) cadaveric model. The stance phase of level walking was simulated in 10 midtibia cadaveric specimens using a validated 6-degree of freedom robot. Bone motions and plantar pressure were collected in 3 conditions: intact, sPCFD, and after PB-to-PL transfer. The PB-to-PL transfer was performed by transecting the PB and advancing the proximal stump 1 cm into the PL. Outcome measures included the change in joint rotation of the talonavicular, first naviculocuneiform, and first tarsometatarsal joints between conditions. Plantar pressure outcome measures included the maximum force, peak pressure under the first metatarsal, and the lateral-to-medial forefoot average pressure ratio. Compared to the sPCFD condition, the PB-to-PL transfer resulted in significant increases in talonavicular plantarflexion and adduction of 68% and 72%, respectively, during simulated late stance phase. Talonavicular eversion also decreased in simulated late stance by 53%. Relative to the sPCFD condition, the PB-to-PL transfer also resulted in a 17% increase (P = .045) in maximum force and a 45-kPa increase (P = .038) in peak pressure under the first metatarsal, along with a medial shift in forefoot pressure. The results from this cadaver-based simulation suggest that the addition of a PB-to-PL transfer as part of the surgical management of the flexible PCFD may aid in correction of deformity and increase the plantarflexion force under the first metatarsal. This study provides biomechanical evidence to support the addition of a PB-to-PL tendon transfer in the surgical treatment of flexible PCFD.

Locking plate versus K-wires and cast fixation in lateral closing-wedge osteotomy for cubitus varus deformity.

The aim of this study was to assess the clinical and radiographic outcomes of cubitus varus treatments based on different fixation methods: Locking plate vs. Kirschner-wires (K-wires) and cast fixation. This retrospective study of 28 patients was performed in lateral-wedge osteotomy for cubitus varus deformity in our hospital from July 2018 to July 2020. 14 patients in group A were treated by locking plate after lateral closing-wedge osteotomy, whereas other 14 patients were treated by K-wires in group B. We measured the bony union and carrying angle. The clinical and radiographic outcomes were assessed according to the Bellemore criteria. No nonunion, neurovascular injury or myositis ossificans was noted at follow-up. In group A, 1 patient with lateral condylar prominence was found. In group B, 2 patients with pinning site infection were treated successfully with oral antibiotics and 2 patients needed revision surgery for residual varus. According to the Bellemore criteria, statistically significant difference was noted between the two groups (P = 0.0458). In the present study, no statistically significant difference was noted in the length of incision and operation time between the 2 groups (P > 0.05). However, the postoperative carrying angle was significantly different at final follow-up between the 2 groups (P < 0.01). Compared with K-wires and cast fixation, we recommend the wedge osteotomy with lateral locking plate to treat the cubitus varus deformity because locking plate could achieve better functional and cosmetic results and stabilize the distal humerus rigidly.

Management of post-traumatic ankle deformities in children.

The objective of this clinical appraisal was to assess the clinical-radiological results of ankle deformity correction secondary to physeal injury, utilizing the methods based on the age of the child, site & severity of the deformity, remaining growth potential, condition of the soft tissue envelop and integrity of neurovascular status. Fifteen subjects ≤ 16 years of age, with angular deformities of the ankle secondary to physeal injury, were included. Deformities secondary to infection and pathological fractures were excluded. Demographic data, type of injury, treatment method, and follow-up were recorded from the case files. Treatment categories included osteotomies for acute correction (> 10 years) and growth modulation (≤ 10 years). Male to female ratio was 7:8, with an average age of 11.8 ± 2.31 years (range 9-16 years). The right and left ratio was 7:8. Mean duration of follow-up was 1 year and 4 months. Gradual deformity correction was done in 2 cases utilizing the principle of growth modulation, while acute correction by osteotomy was done in 13 cases. The average pre-operative ankle deformity was 20.8 ± 3.11 degrees (Range -25 to 24 degrees). Radiological union was attained at a mean of 11 weeks (8-24). Nine patients achieved neutral ankle alignment. The mean residual varus was 2.3°, and the valgus was 4°. There was a statistically significant improvement of the AOFAS score by 17 points from a mean pre-operative score of 57 (44-84) to 74 (56-100) points at the final follow-up (p-value < 0.001). The average pre-operative shortening was 2.36 ± 0.21 cm, which was completely corrected in 9 individuals. Management of angular deformities around the ankle calls attention to correcting the resultant angular deformity and/or limb length disparity, utilizing acute or gradual correction. A successful outcome depends on early recognition and patient-specific treatment of paediatric ankle fracture patterns. Correlating the results of our study with the available literature, we feel that both acute or gradual correction for angular deformities around the ankle is a feasible solution as long as principles of deformity correction are adhered to. Techniques for salvaging and restoring the viability of injured physeal plate warrant additional research.

Residual varus alignment after posterior-stabilized total knee arthroplasty limits medial soft tissue remodeling

BackgroundProper lower limb alignment and soft tissue balance are significant indicators to measure the success of total knee arthroplasty (TKA). Previous studies have confirmed that soft tissue relaxation around the knee after TKA will change over time; however, the relationship between lower limb alignment and soft tissue balance after TKA remains unclear. We studied (1) whether the change of soft tissue balance around the knee with time after posterior-stabilized (PS) TKA would affect the alignment of the lower limbs; (2) Whether the accuracy of lower limb alignment during PS TKA affects postoperative soft tissue remodeling.MethodsIn this study, 100 patients were recruited after PS TKA. Among them, 50 patients with a hip knee ankle (HKA) angle of ≤ ± 3° were set as the neutral group, and 50 patients with an HKA angle of > ± 3° were set as the deviation group. The imaging results measured the HKA angle before the operation as well as the HKA, varus, and valgus angles at 1, 3, 6, 12, and 24 months after TKA. Clinical assessment included range of motion (ROM), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), and Knee Society Score (KSS).ResultsEight people were excluded from the study. After the exclusion, the study enrolled 47 patients in the neutral group and 45 patients in the deviant group and were followed for up to 2 years. There was no statistical significance in mean varus angles as well as HKA angle changes during the follow-up phase of each groups (P > 0.05). The mean valgus angles of the patients in the neutral group group were 2.47°, 3.45°, 3.63°, 3.60° and 3.63°, and in the deviation group were 2.45° (P = 0.841), 2.88° (P < 0.001), 3.07° (P < 0.001), 3.06° (P < 0.001), and 3.10° (P < 0.001). ROM, WOMAC and KSS of the two groups were significantly improved after operation, with no difference between the two groups.ConclusionThis study shows that whether the alignment is accurate or not in the early stage after TKA, the relaxation of the medial and lateral soft tissues of the knee joint change; however, this change will not significantly affect the alignment of the lower limbs. Postoperative residual varus deformity limits medial soft tissue remodeling.Level of evidenceIII.

Peroneus Brevis to Longus Tendon Transfer in the Treatment of the Flexible Progressive Collapsing Foot Deformity: A Cadaveric Study

Category: Midfoot/Forefoot; Hindfoot Introduction/Purpose: Although operative treatment of the flexible progressive collapsing foot deformity (PCFD) remains controversial, correction of residual forefoot varus and stabilization of the medial column are important components of reconstruction. An opening wedge medial cuneiform osteotomy or first tarsometatarsal fusion is traditionally performed to plantarflex the first metatarsal. More recently, tendon transfers such as a peroneus brevis (PB) to peroneus longus (PL) have been proposed. However, there is little data to support their use. The aim of our study was to determine the effect of an isolated PB- to-PL transfer (PBT) on medial column and hindfoot joint kinematics in a simulated PCFD (sPCFD) cadaveric model using a robotic gait simulator. We hypothesized that a PBT in a sPCFD model would partially restore kinematics to the intact state. Methods: A validated six-degree of freedom robot (Baxter et al., 2016) was used to simulate the stance phase of level walking for 6 mid-tibia cadaveric specimens (3 male; age: 72 ± 8 years). An eight-camera motion capture system was used to track reflective markers fixed to bones of the foot and ankle. Three conditions were tested for each specimen: intact, sPCFD (Henry et al., 2022), and after PBT. The PBT was performed by transecting the PB and advancing the proximal stump 1 cm into the PL (Sanhudo, 2019). Outcome measures included kinematics of the talonavicular, subtalar, and first tarsometatarsal joints. Maximum differences between the PBT and sPCFD conditions and 95% confidence intervals (95%CIs) were calculated. The percent deformity correction was determined by dividing the difference between the PB and sPCFD states by the difference between the intact and sPCFD states at the site of maximum deformity correction. Results: Relative to the sPCFD condition, the PBT resulted in a maximum increase in talonavicular plantarflexion of 1.8° (95%CI 0.9°-2.7°) with 159% correction during midstance, decrease in talonavicular abduction of 1.5° (95%CI 0.3°-2.8°) with 65% correction during midstance, and decrease in talonavicular eversion of 2.4° (95%CI 1.2°-3.8°) with 90% correction during mid-to- late stance. All deformities had consistent correction at the talonavicular joint during stance (Figure 1). Additionally, the PBT resulted in a maximum increase in subtalar plantarflexion by 0.8° (95%CI 0.3°-1.8°) with 155% correction in early stance, decrease in subtalar abduction by 0.8° (95%CI 0.5°-1.2°) with 191% correction during early stance, and decrease in subtalar eversion by 1.5° (95%CI 0.5°-2.2°) with 178% correction during mid-stance. There was no effect on first tarsometatarsal joint kinematics. Conclusion: A PB-to-PL transfer in a sPCFD model resulted in the correction of multiple deformities including increased plantarflexion and decreased abduction at the talonavicular joint compared to the sPCFD without the transfer, most notably during PB activation in stance. The PBT also decreased eversion at the talonavicular and subtalar joints. Our results suggest that the addition of a PBT as part of the surgical management of the flexible PCFD contributes to correction of the residual forefoot varus, midfoot abduction, and hindfoot valgus deformities by plantarflexing through the medial column and removing a deforming force on the foot by the PB.

Efficacy of the Ponseti Technique in Correcting Clubfoot Deformity and Influence of Residual Deformity in Patient Reported Outcomes: A Prospective Comparative and Controlled Study

Category: Other; Hindfoot Introduction/Purpose: Clubfoot deformity (CFD) is one of the most common congenital deformities of the foot and ankle and is characterized by different severities of foot equinus, cavus, varus, and adduction. The gold-standard treatment is the Ponseti technique, characterized by serial casting and an Achilles tenotomy. Few studies have assessed long-term outcomes of this treatment, and none have utilized three-dimensional (3D) weightbearing analysis of residual CFD. The goals of this study were to elucidate residual 3D foot deformities in CFD patients treated with the Ponseti technique and to compare them with healthy controls. We also aimed to assess how these deformities influenced patient-reported outcomes (PROs). We hypothesized that significant residual deformities would be observed in CFD patients and that these deformities would negatively impact PROs. Methods: IRB-approved, prospective, comparative, and controlled study. We recruited 37 CFD patients (57 feet) treated with the Ponseti technique that had no additional foot and ankle surgical procedures. We also included 14 healthy control volunteers (28 feet) with no history of foot/ankle injuries/deformities. All patients underwent WBCT imaging (CurveBeam, HiRise). Tarsal bones were semi-automatically segmented (Bonelogic®, Disior), and several automatic measurements assessing cavus, varus, adductus, and overall 3D deformity (Foot and Ankle Offset – FAO) were performed. Measurements were then correlated with PROs, which included Visual Analogue Scale for pain, PROMIS general health, PROMIS physical function and pain interference, pain catastrophizing scale (PCS), and European Foot and Ankle Society (EFAS) score. Paired T-tests or Paired Wilcoxon were utilized to compare measurements between CFD patients and controls, depending on normality distribution. A multivariate regression analysis assessed the relationship between residual deformities and PROs in CFD patients. P-values &lt; 0.05 were considered significant. Results: No significant overall residual 3D-deformity was found, with similar FAO measurements in CFD and controls (respectively, 2.63% and 3.2%/P=0.58). Slight cavus overcorrection was observed in CFD, with sagittal plane talus-first metatarsal angle of -0.12° versus -5.2o (p=0.04) and calcaneal inclination angle of 13.01° versus 21.5°, respectively. Varus under-correction was identified in CFD patients, with decreased sagittal and axial talocalcaneal angles (44.3o vs. 57.5o/p &lt; 0.0001 and 17.7o vs. 25.78o/p=0.0012, respectively). Similarly, adductus under-correction was observed in CFD, with talonavicular coverage angle 18.63o vs. 29.19o (p &lt; 0.0001). In the multivariate regression analysis, cavus overcorrection (sagittal talus-first metatarsal angle) was the only deformity influencing VAS (R2=0.19/P=0.02) and EFAS-Scores (R2=0.27/p=0.002). Residual varus deformity (sagittal plane talocalcaneal angle) was the only deformity influencing PROMIS Pain Interference (R2=0.14/p=0.038) and Physical Function (R2=0.32/p=0.0007). Conclusion: This study highlights the efficacy of the Ponseti technique in treating the overall 3D foot and ankle deformity in CFD patients, realigning the ankle joint and the weightbearing foot tripod. However, residual CFD components were identified, including overcorrection of the cavus and under-correction of the adductus and varus deformities. Overcorrection of the cavus negatively influenced VAS pain and EFAS scores, and under-correction of the varus negatively influenced PROMIS scores. The results of this study could potentially guide CFD treatment with the Ponseti technique, with focus on improved correction of the varus and avoidance of overcorrection of the cavus deformities.

Paper 22: High Tibial Osteotomy: Return to Duty in an Active Duty Military Population

Objectives: Evidence on both return to sport and work following high tibial osteotomy (HTO) has been limited, especially in a young, military population with high occupational demands. The purpose of this study was two-fold: 1) to identify if objective measures of preoperative knee condition severity or intraoperative correction were associated with successful return to duty and 2) to assess if postoperative complications and return to the operating room were associated with successful return to duty. Methods: A retrospective cohort study was performed of patients in the Military Health System who underwent HTO between 2003 and 2018. All patients were between 18 and 55 years and presented with osteoarthritis isolated to the medial compartment with or without other knee injuries. Concomitant meniscal and cartilage procedures were included while ligamentous procedures were excluded as they were viewed as a separate pathology. The inclusion criteria were as follows: active duty status at the time of the index procedure and two-year minimum follow-up with both preoperative knee radiographs and pre- and postoperative long-leg alignment radiographs. Preoperative Kellgren-Lawrence grade, pre- and postoperative hip-knee-ankle angle, and postoperative weightbearing axis were collected. The primary outcome was return to duty, stratified by failure defined as medical separation from the military or conversion to total knee arthroplasty. Success was defined as remaining on active duty without restriction while modified success was defined as remaining on active duty with permanent activity restrictions. The secondary outcome was reoperation for any reason. Results: Fifty-five HTOs were performed in 50 patients with a mean age of 39.0 years (range 22.8-55.0). Mean follow up was 5.0 years (range 2.1-10.7). 18.2% (10/55 knees) failed HTO (one conversion to TKA, nine medical separations), 27.3% (15/55 additional knees) had permanent activity restrictions, and 54.5% (30/55 knees) returned to active duty without restriction. 34.5% of HTOs had reoperation at any time point and return to the operating room was associated with medical separation (p=0.027). Reoperation occurred for unplanned removal of hardware (7), irrigation and debridement (4), revision HTO (3), meniscal transplant (2), meniscal repair (1), spinal cord stimulator placement (1), and decompressive fasciotomies (1). Younger age was associated with both medical separation (p=0.003) and permanent restrictions (p=0.006) following HTO and was the only significant variable identified on multiple logistic regression analysis. Patients with residual postoperative varus deformity &gt;5 degrees were more likely to undergo medical separation (p=0.023). Conclusions: When performed in a military population, HTO succeeded in returning 54.5% of knees to full duty without restriction despite 34.5% of knees requiring reoperation for complications. However, HTOs with residual varus deformity or complications requiring additional procedures were associated with lower return to duty rates. No correlation was identified between return to duty and osteoarthritis grading or amount of deformity. [Table: see text][Table: see text]

Combination of a High Residual Varus and Joint-Line Lowering Strongly Increases the Risk of Early Implant Failure in Medial Unicompartmental Knee Arthroplasty

BackgroundOutliers in implant positioning, malalignment, and joint line height change are risk factors for unicompartmental knee arthroplasty (UKA) failure. However, their relationships and patterns in large datasets remain unexplored. This study assessed medial UKA survival in a large cohort and explored associated risk factors. MethodsThis was a retrospective cohort study on medial UKA patients (2011 to 2019). Radiological outcomes included tibial implant positioning in the coronal plane, posterior tibial slope, residual knee deformity, and joint line restitution. Survival rate at last follow-up was recorded. Multinomial logistic regression analyzed risk factors, incorporating demographic and univariate analysis data. ResultsThree hundred and sixty-six knees met inclusion criteria, with 10 lost to follow-up (2.7%). Mean follow-up was 61.3 months [24.1 to 135.1]. 5- and 10-year implant survival rates were 92% ± 1.6 and 88.4% ± 3.8, respectively. Multivariate analysis identified post-operative hip-knee-ankle angle (HKA) ≤ 175° (OR = 5.30 [1.64 to 17.13], P = .005) and joint line lowering ≥2 mm (OR = 8.86 [2.06 to 38.06]) as significant risk factors for tibial implant failure. Their combination carried a significantly high risk of failure (OR = 10.3 [3.1 to 34.3]). Post-operative HKA < 175° was common in knees with pre-operative HKA < 172°. ConclusionThis study reports encouraging 5- and 10-year survival outcomes for medial UKA. Tibial loosening was the main reason for revision. Patients with joint line lowering ≥ 2 mm and post-operative HKA ≤ 175° were at high risk of tibial implant failure. Surgeons should carefully restore the joint line in cases of pre-operative HKA < 172°.

Valgus alignment of the femoral component is associated with higher revision rates 10years after TKA.

Appropriate positioning and alignment of tibial and femoral component in primary total knee arthroplasty (TKA) are factors of major importance directly related to patient satisfaction and implant survival. Most literature works elaborate on overall post-operative alignment and its correlation to implant survival. However, less is known about the impact of individual component alignment. The purpose of this study was to investigate the effect of undercorrection of overall alignment as well as the effect of individual tibial and femoral component alignment on the post-operative failure rate after total knee arthroplasty. Clinical and radiographic data of primary TKA cases from 2002 to 2004, with a minimum of 10-year follow-up, were retrospectively reviewed. The pre- and post-operative hip-knee-ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA) and mechanical medial proximal tibial angle (mMPTA) were measured on weight-bearing, full-length antero-posterior lower limb radiographs. Statistical analysis was performed to establish the correlation between both overall and implant alignment and revision rate. In total, 379 primary TKA cases were evaluated. The mean time of follow-up was 12.9years (range 10.3-15.9years, SD = 1.8). Nine out of 379 cases were revised due to aseptic loosening; the mean time to revision was 5.5years (range 1.0-15.5years, SD = 4.6). Varus undercorrection of overall alignment was not associated with a higher rate of revision (p = 0.316). Post-operative valgus femoral alignment (mLDFA < 87°) contributed to a significant decreased prosthesis survival in contrast to neutral femoral alignment (revision rate valgus group: 10.7% and neutral group: 1.7%; p = 0.003). Post-operative tibial mechanical alignment was not identified as a significant predictor for implant survival (revision rate varus group: 2.9% and neutral group: 2.4%; p = 0.855). Primary TKA showed significantly higher revision rates when the femoral component was placed in > 3° of valgus (mLDFA < 87°). In contrast, postoperative overall residual varus alignment (HKA) and varus alignment of the tibial component were not related to higher revision rates at a minimum 10-year follow-up after TKA. These findings should be considered when choosing component position in individualised TKA. III.

Anatomic Fibular Collateral Ligament and Anterior Cruciate Ligament Reconstruction With Concomitant Biceps Femoris Avulsion Repair

Background: Injuries to the fibular collateral ligament (FCL) seldom occur in isolation and may present with a concomitant injury to the biceps femoris tendon and anterior cruciate ligament (ACL). Injuries to structures of the posterolateral corner (PLC) lead to varus and rotational instability of the knee, subjecting the cruciate ligaments to increased forces that may result in graft failure. Therefore, reconstruction of these structures should be performed concurrently with the ACL. Indications: Grade III FCL injuries heal poorly without operative treatment and often result in residual varus instability of the knee that increases medial knee compartment forces, and forces on both the native ACL and the graft status post ACL reconstruction. Therefore, preservation of biomechanical stability and long-term health of the knee are reliant on addressing injuries to the PLC surgically. Technique Description: A key concept of this surgical technique is a meticulous peroneal nerve neurolysis in the setting of altered biceps femoris anatomy, and the proper order of the surgical steps for tunnel creation, graft passage, and fixation and suture anchor insertion to achieve optimal patient outcomes. The described technique involves a lateral surgical approach, peroneal neurolysis, and preparation of fibular and femoral FCL tunnels, followed by a Bone-patellar tendon-bone graft (BTB) graft harvest. Attention is then turned to intra-articular work including the diagnostic arthroscopy, femoral and tibial tunnel preparation, passage of the ACL graft, and fixation of the grafts in femoral tunnels. Last, fixation is achieved in the following order: FCL graft on fibula, ACL graft on tibia, and biceps femoris tendon to fibular head. Results: Compared with the preoperative state, Moulton et al reported significant improvements in the average Lysholm and Western Ontario scores at 2.7 years postoperatively following anatomic FCL reconstrution. Furthermore, Thompson et al reported on primary suture anchor repair of distal biceps femoris in 22 elite athletes and reported that all patients had returned to their preinjury level of sporting activity at 2-year follow-up. Discussion: Anatomic reconstructions of the FCL and ACL, such as the one described in our technique, effectively restore near native knee biomechanics and offer superior clinical outcomes compared with nonanatomic-based FCL reconstructions. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Functional scores and prosthetic implant placement are different for navigated medial UKA left in varus alignment.

The purpose of this study was to analyze the clinical outcomes and radiologic position of the knee in two groups of patients after medial unicompartmental knee arthroplasty (UKA): one group with residual varus axis (RVA) alignment and other one with neutral mechanical axis (NMA) of the lower limb. All patients who underwent UKA between January 2015 and January 2018 were evaluated retrospectively. Inclusion criteria were: medial UKA for isolated medial femoro-tibial osteoarthritis, a varus deformity of < 15°, and a minimal follow-up of 2years. All patients had a preoperative and postoperative clinical examination with functional scores (New International Knee Score (NewIKS) and Knee injury and Osteoarthritis Outcome Score (KOOS) and radiographs. Preoperative and postoperative values for continuous outcomes were compared using the Student's t test for paired data and differences between the groups were compared with the Mann-Whitney U test. p < 0.05 was considered statistically significant. The RVA group consisted of 48 cases of medial UKA in 48 patients (22 females). Mean postoperative hip-knee-ankle (HKA) angle was 174.3° ± 2.8 and the corresponding mean AKI angle (tibial mechanical angle) was 82.9° ± 2.9. The NMA group consisted of 35 cases of medial UKA in 35 patients (14 females). Mean postoperative HKA angle was 178.9° ± 3 and the corresponding mean AKI angle was 85.5° ± 3.1. A significant difference was found between the two groups for the KOOS score and for global NewIKS, with a better score in the RVA group. RVA alignment after medial UKA results in a significant improvement in functional knee scores at 2-year post-surgery. Return to sport and recreational activities was better than in patients with postoperative NMA. Level 3; retrospective cohort study.

Postoperative full leg radiographs exhibit less residual coronal varus deformity compared to intraoperative measurements in robotic arm-assisted total knee arthroplasty with the MAKO™ system

PurposeRobotic arm-assisted total knee arthroplasty (raTKA), currently a major trend in knee arthroplasty, aims to improve the accuracy of implant positioning and limb alignment. However, it is unclear whether and to what extent manual radiographic and navigation measurements with the MAKO™ system correlate. Nonetheless, a high agreement would be crucial to reliably achieve the desired limb alignment.MethodsThirty-six consecutive patients with osteoarthritis and a slight-to-moderate varus deformity undergoing raTKA were prospectively included in this study. Prior to surgery and at follow-up, a full leg radiograph (FLR) under weight-bearing conditions was performed. In addition, a computed tomography (CT) scan was conducted for preoperative planning. The hip–knee–ankle angle (HKA), mechanical lateral distal femur angle (mLDFA), mechanical medial proximal tibial angle (mMPTA) and joint line convergence angle (JLCA) were measured in the preoperative and follow-up FLR as well as in the CT scout (without weight-bearing) by three independent raters. Furthermore, the HKA was intraoperatively assessed with the MAKO™ system before and after raTKA.ResultsSignificantly higher HKA values were identified for intraoperative deformity assessment using the MAKO system compared to the preoperative FLR and CT scouts (p = 0.006; p = 0.05). Intraoperative assessment of the HKA with final implants showed a mean residual varus deformity of 3.2° ± 1.9°, whereas a significantly lower residual varus deformity of 1.4° ± 1.9° was identified in the postoperative FLR (p < 0.001). The mMPTA was significantly higher in the preoperative FLR than in the CT scouts (p < 0.001). Intraoperatively, the mMPTA was adjusted to a mean of 87.5° ± 0.9° with final implants, while significantly higher values were measured in postoperative FLRs (p < 0.001). Concerning the mLDFA, no significant differences could be identified.ConclusionThe clinical importance of this study lies in the finding that there is a difference between residual varus deformity measured intraoperatively with the MAKO™ system and those measured in postoperative FLRs. This has implications for preoperative planning as well as intraoperative fine-tuning of the implant position during raTKA to avoid overcorrection of knees with slight-to-moderate varus osteoarthritis.Level of evidenceLevel IV.

Mid-Term Clinical and Radiological Results at a Tertiary Care Hospital in Türkiye: Is Residual Varus Really Important After Mechanically-Aligned Total Knee Arthroplasty?

Traditionally, in total knee arthroplasty (TKA), it is aimed to keep the mechanical axis of the lower extremity neutral (mechanical alignment:3° varus-valgus in thecoronalplane) to improve long-term outcomes. This study aimed to assess the mid-term radiological and clinical results of patients with postoperative residual varus (more than 3° of varus) aftermechanically-aligned TKA. A total of 616 individuals who had undergoneTKAforprimaryknee osteoarthritisbetween 2008 and 2013 in our tertiary care hospital were retrospectively examined.All TKAs were performed with the mechanical alignment strategy.For radiological evaluation, hip-knee-ankle (HKA) angle, knee alignment angle (KAA), mechanical medial proximal tibial angle (mMPTA), knee inclination (KI), joint line orientation angle relative to ground (JLOA-G), posterior tibial slope (PS), joint line convergence angle (JLCA) were measured. Besides, patients' latest radiographs were screened for any clue of aseptic loosening or mechanical failure. Knee Society Score (KSS) (knee and functional subgroups), and Lysholm, Oxford, and Tegner scores were used for clinical evaluation. In addition, knee flexion and extension limitations were assessed. After applying the exclusion criteria, a minimum of five-year follow-up result of 110 patients was demonstrated.There were 101 females (92%) and nine males (8%). The mean follow-up time was 65.8 ± 6.3 months (range: 60.8-75.8 years). The mean age was 65.9 ± 7.7 years (range: 39 to 89 years). Thepreoperative mean mechanical axis angle of the lower extremity was17.3° ± 7.8° (range: 13.4-43.9°), whereas it was 8.3° ± 3.6° (range: 3.2-19.8°) postoperatively.The preoperative mean flexion angle was 90.7° ±23.8° (range: 40-130°), andthe extension limitation was -2.5° ± 7.4° (range: -40-0°), whereas, postoperatively, they were102.8° ± 15.4° (range from 40° to 150°) and -3.7° ± 7.5°(range from -40° to0°), respectively.The latest follow-up's mean KSS knee subgroup was 67 ± 18.4 (range: 12-93), the mean KSS functional subgroup was 74 ± 23.6 (range: 20-100), the mean Lysholm score was 81.7 ± 15.7 (range:25-100), the mean Tegner score was 3.65 ± 0.99 (range: 1-5), the mean Oxford score was 37.4 ± 6.5 (range: 9-48). There was no patient with aseptic loosening or mechanical failure. In the mid-term follow-up of patients with residual varus aftermechanically-alignedTKA, satisfactoryclinicaland radiological results were obtained without aseptic loosening or implant failure.

Single-Stage Tibial Osteotomy for Correction of Genu Varum Deformity in Children

Conservative and operative treatments with gradual or acute correction of severe varus deformities of the leg have been described. We evaluated whether the corrective osteotomy used within the NGO Mercy Ships is an effective treatment for genu varum deformity of different etiologies in children and which patient specific factors have an influence on the radiographic outcome. In total, 208 tibial valgisation osteotomies were performed in 124 patients between 2013 and 2017. The patients' mean age at the time of surgery was 8.4 (2.9 to 16.9 (min/max)) years. Seven radiographically measured angles were used to assess the deformity. Clinical photographs taken pre- and postoperatively were assessed. The mean time between the surgery and the end of physiotherapeutic treatment was 13.5 (7.3 to 28) weeks. Complications were monitored and classified according to the modified Clavien-Dindo-classification system. The mean preoperative mechanical tibiofemoral angle was 42.1° varus (range: 85°-12° varus). The mean postoperative mechanical tibiofemoral angle was 4.3° varus (range: 30° varus-13° valgus). The factors predicting a residual varus deformity were higher age, greater preoperative varus deformity and the diagnosis of Blount disease. The tibiofemoral angle measured on routine clinical photographs correlated well with the radiographic measurements. The single-stage tibial osteotomy described is a simple, safe and cost-effective technique to correct three-dimensional deformities of the tibia. Our study shows very good mean postoperative results, but with a higher variability than in other studies published. Nevertheless, considering the severity of preoperative deformities and the limited opportunities for aftercare, this method is excellent for the correction of varus deformities.