Increased medial talar tilt may incite ankle pain and predispose ankle osteoarthritis after correction of severity of knee varus deformity among patients undergoing bilateral total knee arthroplasty: a prospective observation

PURPOSE

Patients with varus knee osteoarthritis usually compensate at the ankle and typically walk with hindfoot valgus alignment. As the neutral weight-bearing axis of the lower limbs is restored with Total Knee Arthroplasty (TKA), ankle and hindfoot biomechanics also acutely change. This study aims to investigate whether any ankle clinical-radiographical changes occur as a result of bilateral mechanical TKA in patients with bilateral Osteoarthritis knee at a minimum follow-up of 6 months.

METHODS

The prospective observational study included 61 patients (122 knees) undergoing simultaneous bilateral TKA (mechanical alignment). Tibio-talar angle(TTA), tibial Anterior Surface angle (TAS), lateral distal tibial angle (LDTA), talar-tilt angle (TT), anatomical talocrural angle (aTC), ground surface and distal tibial plafond angle (GP), ground surface and an upper surface of talus angle (GT)and tibial plateau and tibial plafond angle (PP) were measured on long-film radiographs to look for changes in the ankle, whereas functional assessment was done using American Foot and Ankle Society (AOFAS), Foot and Ankle Disability Index (FADI), and Forgotten Joint (FJS-12) scores. Patients were sub-grouped based on the Hip-Knee-Ankle (HKA) axis, and the effect of the severity of knee varus on the ankles after TKA was also analyzed. The minimum follow-up was 6 months.

RESULTS

A significant decrease in the tibial plateau-tibial plafond (PP), ground-tibial plafond (GP), and ground-talar dome (GT) angles was noted after TKA (p-value < 0.05). Postoperative functional parameters were comparable to the preoperative status except for FADI, which significantly improved (p-value-0.03). Sub-group analysis based on the severity of knee varus (HKA) revealed GT to be most significantly reduced (p-value-0.036), while the talar tilt (TT) increased (p-value-0.044). Functional outcomes of the ankles clinically improved with the correction of severe knee varus after TKA. At a mean follow-up of 13.2 months post-TKA, 7 out of 61 (11.4%) patients complained of post-TKA ipsilateral ankle pain.

CONCLUSION

Mechanically aligned bilateral TKA in severe varus deformity of the knee significantly decreases the GT angle but increases the varus tilt of the talus with lateral talar incongruency and under-coverage. Although the acute correction of severe knee varus deformity aligns the tibia more neutrally, resulting in an overall clinically evident improvement in ankle functional outcome, the increased varus talar tilt remains a deep concern.

LEVEL OF EVIDENCE

Prospective, observational, comparative study Level II.

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

BACKGROUND

Proper 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.

METHODS

In 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).

RESULTS

Eight 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.

CONCLUSION

This 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 EVIDENCE

III.

Alignment strategy for different types of varus knee with generic instruments: Mechanical alignment or kinematic alignment?

OBJECTIVE

A thorough examination of the available approaches is crucial to comprehensively understand the variance among the alignment strategies employed in total knee arthroplasty (TKA). In this study, we assessed the functional outcomes during the perioperative and postoperative periods of TKA in patients using generic instruments with varus knee to compare the mechanical alignment (MA) and kinematic alignment (KA) procedures.

METHODS

A total of 127 patients from the First Affiliated Hospital of Wannan Medical College who had undergone unilateral TKA between November 2019 and April 2021 were included. The patients with varus knee deformity were categorized into two groups [type I (n = 64) and type IV (n = 63)] based on the modified coronal plane alignment of the knee (mCPAK) classification. The type I and IV groups were further subdivided into MA (n = 30 and n = 32) and KA subgroups (n = 34 and n = 21), respectively. The clinical information collected included sex, surgical side, age, body mass index, and perioperative data [including operation time, intraoperative blood loss, length of hospital stay, and the American Society of Anesthesiologists (ASA) classification]. All patients were monitored for 12 months post-surgery to evaluate the recovery of knee joint function. During this period, the Knee Disability and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) and the active range of motion (AROM) and visual analog scale (VAS) pain scores were compared at different time points, i.e., before the operation and 6 weeks, 6 months, and 12 months post-operation. Additionally, the patients' subjective experiences were assessed at 6 and 12 months post-surgery using Forgotten Joint Score Knee (FJS-12 Knee), while complications were recorded throughout the monitoring period.

RESULTS

No significant variances were observed in ASA classification, operation duration, blood loss volume during surgery, and hospital stay length between the patients who underwent KA TKA and those who received MA TKA (P > 0.05). During the initial 6 weeks post-operation, the KA group exhibited a significantly reduced average VAS pain score (P < 0.05), with no such differences at 6 months and 1 year after the surgery (P > 0.05). Furthermore, the KA group had significantly higher scores on the KOOS JR at 6 weeks, 6 months, and 1 year following the surgery (P < 0.05). Moreover, the AROM score of the KA group significantly improved only at 6 weeks after the surgery (P < 0.05); however, no prominent differences were found at 6 months and 1 year after the operation (P > 0.05). The KA cohort also exhibited a significant increase in FJS-12 Knee at 1 year following the operation (P < 0.05), whereas no such difference was detected at 6 months following the surgery (P > 0.05). Thus, compared to the MA method, the KA procedure provided pain relief and improved active motion range within 6 weeks after the surgery in patients undergoing TKA. Further, the KOOS JR exhibited significant increases at 6 weeks, 6 months, and 1 year while the FJS-12 Knee demonstrated a significant increase at 1 year after the KA TKA procedure.

CONCLUSION

Therefore, our study results suggest that the KA approach can be considered in patients using generic instruments with varus alignment of the knee, particularly those with mCPAK type I and IV varus knees, to help improve patient satisfaction.

Using multivariate nonlinear mixed-effects model to investigate factors influencing symptom improvement after high tibial osteotomy in combination with bone marrow concentrate injection for medial compartment knee osteoarthritis: a prospective, open-label study

PURPOSE

To investigate the effects of various demographic, structural, radiographic, and clinical factors on the prognosis of patients with medial compartmental knee osteoarthritis with varus deformity undergoing medial opening wedge high tibial osteotomy (HTO) in combination with bone marrow concentrate (BMC) injection.

METHODS

In this prospective study, 20 patients underwent medial opening wedge HTO in combination with BMC injection with 12 months of follow-up. The structural and radiographic outcomes were evaluated by femorotibial angle and posterior tibial slope angle. The clinical outcomes were evaluated by visual analogue scale (VAS), Western Ontario and McMaster Universities Arthritis Index (WOMAC), and The Knee injury and Osteoarthritis Outcome Score (KOOS). Multivariate nonlinear mixed-effects models with asymptotic regressions were used to model the trajectory of symptom improvement.

RESULTS

Medial opening wedge HTO in combination with BMC corrected the malalignment of the knee and led to significant symptom relief. The improvement of clinical symptoms reached a plateau 6 months after the surgery. Greater symptom severity at baseline and lower Kellgren-Lawrance (KL) grades were correlated with better post-operative clinical outcomes. Body-Mass-Index (BMI), femorotibial angle, age, and sex may also play a role in influencing the extent of symptom relief.

CONCLUSION

Symptom severity at baseline is important for prognosis prediction. In clinical practice, we suggest that the evaluation of clinical features and functional status of the patients be more emphasised.

Ankle and Hindfoot Alignment Changes in Advanced OA Varus Knees After Cruciate Retaining Total Knee Arthroplasty: A Prospective Cohort Study

Background

Correct alignment of the knee is considered to be one of the most influential factors in determining the long-term outcomes after Total Knee Arthroplasty (TKA), and is believed to decrease both the mechanical and shear stresses placed on the bearing surfaces, as well as the bone/prosthesis interfaces. Compensatory malalignment of ankle and hindfoot is a recognized cause for ankle disability and deformity in long-standing osteoarthritic patients with varus deformity. This study aims to assess changes in ipsilateral ankle and hindfoot if any, pre- and post-operative TKA.

Methods

65 knees of 54 patients of osteoarthritis knee were evaluated for alignment in knee, ankle and hindfoot pre- and post-TKA. Pre- and post-operative scanogram were evaluated for knee and ankle alignment. Hindfoot alignment view was used to calculate hindfoot alignment angle. All parameters were compared before TKA and after 10 weeks TKA and Wilcoxon signed rank test was used to test the significance of the values.

Results

Mean age of the patients was 62.9 years (49-80 years). Mean varus before surgery was 14.49 which changed to 4.01 and mean hindfoot angle valgus reduced from 9.23 to 6.62, both of which was found significant. Significant changes were also observed between pre- and post-op measurements of knee society scores, AOFAS, with improved functional outcomes both in knee and ankle.

Conclusion

This study reveals the radiological and functional changes occurring in the ankle and hindfoot after acute correction of long-standing varus deformity of the knee using total knee arthroplasty. Hindfoot valgus alignment in varus knees decreased significantly post-TKA without any intervention at ankle level. In cases undergoing knee arthroplasty, effect of the acute change in the alignment of the knee on the ankle and hindfoot should be taken into consideration and the amount of correction of knee alignment can be a predictor of correction of ankle and hindfoot malalignment too. The lateral benefit of improvement in ankle pain after TKA is a significant gain in this study.

A single type of varus knee does not exist: morphotyping and gap analysis in varus OA

PURPOSE

To achieve a higher level of satisfaction in patients having undergone Total Knee Arthroplasty (TKA), a more personalized approach has been discussed recently. It can be assumed that a more profound knowledge of bony morphology and ligamentous situation would be beneficial. While CT/MRI can give 3D information on bone morphology, the understanding of the ligamentous situation in different flexion angles is still incomplete. In this study, the dynamic gap widths of a large number of varus knees were assessed in various flexion angles, to find out whether all varus knees behave similar or have more individual soft tissue patterns. Additionally, it was investigated whether the amount of varus deformity or other patient factors have an effect on joint gap widths.

METHODS

A series of 1000 consecutive TKA patients, including their CAS data and patient records were analyzed. Joint gap widths in multiple flexion angles (0°, 30°, 60°, 90°) were measured in mm and differences between the joint gaps were compared. A "standard" varus knee was defined as follows: (1) Lateral extension gap greater than medial, (2) lateral flexion gap greater than medial, and (3) flexion gap greater than extension gap. The percentage of fulfillment was tested for each and all criteria. To measure the influence of varus deformity on gap width difference, three subgroups were formed based on the deformity. Data were analyzed at 0°, 30°, 60° and 90° flexion. The effect of patient factors (gender, BMI, age) on gap sizes was tested by performing subgroup analyses.

RESULTS

Only 444 of 680 (65%) patients met all three varus knee criteria. The lateral extension gap (4.1 mm) was significantly larger than the medial extension gap (0.6 mm) in 657 (97%) patients and the gap difference highly correlated with the amount of varus deformity (r² = 0.62). In all flexion positions, however, no correlation between gap differences and varus deformity existed. Women had significantly larger extension and flexion gaps. Age and BMI showed no significant effect on gap widths.

CONCLUSION

Varus knees show a large inter-individual variability regarding gap widths and gap differences. The amount of varus deformity correlates highly with the medio-lateral gap difference in extension, but not in any flexion angle. As varus knees are not all alike, a uniform surgical technique will not treat all varus knees adequately and the individual gap sizes need to be analyzed and addressed accordingly with an individualized balancing technique. Which final balancing goal should be achieved needs to be analyzed in future studies.

LEVEL OF EVIDENCE

Level III.

Varus morphology and its surgical implication in osteoarthritic knee and total knee arthroplasty

BACKGROUND

Knee varus alignment represents a notorious cause of knee osteoarthritis. It can be caused by tibial deformity, combined tibial-femoral deformity and/or ligament imbalance. Understanding malalignment is crucial in total knee arthroplasty to restore frontal plane neutral mechanical axis. The aim of this study was to determine which factor contributes the most to varus osteoarthritic knee and its related surgical implications in performing a total knee arthroplasty.

METHODS

We retrospectively evaluated 140 patients operated for total knee arthroplasty due to a varus knee. Full-leg hip to ankle preoperative X-rays were taken. Radiological parameters recorded were: mechanical axis deviation, hip-knee-ankle, anatomical-mechanical angle, medial neck shaft angle, mechanical lateral distal femoral angle (mLDFA), medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), lateral proximal femoral angle, lateral distal tibial angle (LDTA), femoral bowing, and length of tibia and femur. We also determined ideals tibial and femoral cuts in mm according to mechanical alignment technique. A R2 was calculated based on the linear regression between the predicted values and the observed data.

RESULTS

The greatest contributor to arthritic varus (R = 0.444) was MPTA. Minor contributors were mLDFA (R = 0.076), JLCA (R = 0.1554), LDTA (R = 0.065), and femoral bowing (R = 0.049). We recorded an average of 7.6 mm in lateral tibial cut thickness to restore neutral alignment.

CONCLUSIONS

The radiological major contributor to osteoarthritic varus knee alignment is related to proximal tibia deformity. As a surgical consequence, during performing total knee arthroplasty, the majority of the correction should therefore be made on tibial cut.

Linear mixed modeling on the effects of varus knee surgery on the ankle joint weight-bearing axis

BACKGROUND

Varus knee correction may affect the ankle and subtalar joints and impact the prognosis of ankle arthritis because the weight-bearing load on the lower extremity extends from the hip to the foot. We aimed to evaluate the changes in the mechanical axis and the weight-bearing axis of the ankle after varus knee surgery.

METHODS

Patients with a varus knee were followed up after undergoing high tibial osteotomy or total knee replacement arthroplasty. The inclusion criteria were age (>18 years) and a history of preoperative and postoperative scanograms. The postoperative change to the ankle joint axis point on the mechanical axis and weight-bearing axis according to the hip-knee-ankle angle correction was adjusted by multiple factors using a linear mixed model.

RESULTS

Overall, 257 limbs from 198 patients were evaluated. The linear mixed model showed that the change in the ankle joint axis point on the mechanical axis was not statistically significant after high tibial osteotomy and total knee replacement arthroplasty (p = 0.223). The ankle joint axis point on the weight-bearing axis moved laterally by 0.9% per degree of postoperative hip-knee-ankle angle decrease (p < 0.001).

CONCLUSIONS

Varus knee correction could affect the subtalar joint and the ankle joint. Our findings require consideration when utilized during pre- and postoperative evaluations using the weight-bearing axis of patients undergoing varus knee correction.

Three dimensional CT analysis of the change in rotational alignment in double level osteotomy after double level osteotomy performed for varus osteoarthritic knees

Purpose

To analyze the change in rotational alignment caused by double level osteotomy (DLO) based on comparative three-dimensional image analysis of pre- and postoperative CT images.

Methods

Pre- and postoperative CT examination of the lower extremities were performed with informed consent for 39 consecutive knees undergoing DLO for varus knee deformity. The DLO procedure consisted of closed wedge distal femoral osteotomy (CWDFO) and open wedge high tibial osteotomy (OWHTO). Among those cases, 20 knees complicated with hinge fracture at the osteotomy site were excluded from the analysis to eliminate a confounding factor affecting the results. Consequently, data obtained from 19 knees were subjected to the study analysis while osteotomies with hinge fractures complications were excluded from the study. In the three-dimensional CT image analysis of axial plane images, femoral torsion (the angle between midline along the femoral neck axis and the tangent of the posterior edges of the medial/lateral femoral condyles) and tibial torsion (the angle between the tangent of the posterior edges of the medial/lateral tibial condyles and the transmalleolar axis) were measured. The torsion angle was measured in each of the femurs and the tibias on both pre- and postoperative CT axial images, and the change induced by the osteotomy was calculated and statistically(using Wilcoxon signed-rank test) compared.

Results

The mean pre- and postoperative femoral torsion (anteversion) angles were 29.3° and 31.4° with a significant postoperative increase in internal rotation of the bony segment distal to the osteotomy(P = 0.002). On the tibial side, the mean pre- and postoperative torsion angles were 26.5° and 25.7°, indicating no significant postoperative change(P = 0.199)（NS）.

Conclusions

This study showed that the DLO procedure (combining CWDFO and OWHTO) increased torsion (anteversion) of the femur by 2.1° on average while inducing no significant rotational change on the tibial side.

The ischiofemoral space of the hip is influenced by the frontal knee alignment

PURPOSE

The ischiofemoral distance (IFD), defined as the distance between the ischial tuberosity and the lesser trochanter of the femur, is gaining recognition as an extra-articular cause of hip pain. It is unknown whether the IFD is influenced by the frontal knee alignment. The aim of this study was to determine the influence of realignment surgery around the knee on the IFD. It was hypothesized that valgisation osteotomy around the knee is associated with reduction of the IFD.

METHODS

A consecutive series of 154 patients undergoing frontal realignment procedures around the knee in 2017 were included in this study. Long-leg standing radiographs were obtained before surgery and postoperatively. The IFD was measured between the ischium and the lesser trochanter at three different levels (proximal, middle and distal margins of the lesser trochanter parallel to the horizontal orientation of the pelvis) on standardized long-leg radiographs with the patient in upright standing position. The knee alignment was determined by measuring the hip knee ankle angle, mechanical lateral distal femur angle and the medial mechanical proximal tibia angle. Linear regression was performed to determine the influence of the change of frontal knee alignment on the IFD.

RESULTS

Linear regression showed a direct influence of the overall change in frontal knee alignment on the IFD of the hip, regardless of the site of the osteotomy (β-0.4, confidence-interval - 0.5 to - 0.3, p < 0.001). Valgisation osteotomy around the knee induced a significant reduction of the ipsilateral IFD (p < 0.001), while varisation osteotomy induced a significant increase (p < 0.001). The amount of ISD change was 0.4 mm per corresponding degree of change in frontal knee alignment.

CONCLUSION

These findings are relevant to both the hip and knee surgeons when planning an osteotomy or arthroplasty procedure. Correction of a malalignment of the knee may resolve an ischiofemoral conflict in the hip. The concept deserves inclusion in the diagnostic workup of both the hip and knee joints.

LEVEL OF EVIDENCE

IV.

Effect of the presence of the articular cartilage on the femoral component rotation in total knee arthroplasty in female and varus osteoarthritis knees

Purpose

Surgical techniques for total knee arthroplasty (TKA) require femoral rotational corrections that alter the position of the surface of the posterior femoral joint especially in kinematic alignment. However, preoperative planning of TKA based on computed tomography (CT), without knowing the femoral cartilage thickness, may cause post-surgery failures in femoral rotation. Therefore, this study aimed to evaluate the effects of posterior condyle cartilage thickness on rotational alignment in the femoral component.

Methods

Three-dimensional magnetic resonance imaging (MRI) scans were obtained for 139 male and 531 female osteoarthritis patients. The angles defined by the femoral posterior condylar axis (PCA) and the surgical transepicondylar axis (TEA) were evaluated with respect to the presence of cartilage. Additionally, these effects were evaluated with respect to patient gender and varus/valgus condition.

Results

In all patients, the angle between the TEA and PCA was significantly greater in the presence of cartilage than in the absence of cartilage. This result was also seen in female patients. However, there was no difference in the TEA/PCA angle in male patients based on the presence of cartilage. The TEA/PCA angle was significantly greater in the presence of cartilage than in the absence of cartilage in the female varus group. However, there were no differences in the TEA/PCA angle based on the presence of cartilage in the male varus/valgus and female valgus groups. Cartilage thickness in the posterior femoral condyle was significantly greater on the lateral side than on the medial side in all and male patients. However, there was no difference between the genders regarding cartilage thickness.

Conclusion

Surgical planning for TKA based on CT does not consider articular cartilage and could lead to external malrotation of the femoral implant. Therefore, the effect of the remaining posterior condylar cartilage should be considered by surgeons to prevent over-rotation of the femoral component, especially in female varus knees.

Selective medial release using multiple needle puncturing with a spacer block in situ for correcting severe varus deformity during total knee arthroplasty

INTRODUCTION

We aimed to establish a selective and sequential medial release technique using multiple needle puncturing (MNP) with a spacer block in situ in severe varus deformity during total knee arthroplasty (TKA) and to investigate its efficacy and safety.

MATERIALS AND METHODS

A total of 128 patients with a varus angle >15° were included. Patients were classified according to the tightness of extension and flexion (group 1, no tightness; group 2, extension; group 3, flexion; group 4, extension and flexion). When medial tightness was found on extension, the posterior clearing procedure, including release of the posterior capsule, posterior oblique ligament, and semimembranosus, was performed sequentially. When medial tightness was found on flexion, MNP using an 18-gauge needle with a spacer block in situ was performed at the anterior portion of the superficial MCL (aMCL). Clinical and radiological evaluations including stress radiographs were performed.

RESULTS

Among 128 knees, 110 required medial release (posterior clearing procedure only in 44 [34.3%], MNP with a spacer block in situ at aMCL only in 38 [29.7%], posterior clearing procedure and MNP in 28 [21.9%]). The mediolateral gap imbalances on extension and/or flexion were significantly improved (p < 0.001 in all). There were no significant differences in clinical radiological outcomes among groups. Over-release, iatrogenic transection, and postoperative laxity on the stress radiographs were not observed.

CONCLUSION

The selective and sequential technique using posterior clearing and/or MNP with a spacer block in situ can be a reliable option for managing medial tightness in severe varus deformity during primary TKA.

Changes in lower limb alignment and their effect on the functional outcome after treatment of varus degenerative OA knee by hemicallotasis using modular dynamic HTO fixator

OBJECTIVE

High tibial osteotomy (HTO) is an established procedure to treat medial compartmental osteoarthritis (OA) knee associated with varus deformity. It is well documented that precise correction of deformity and maintenance of correction achieved is important to ensure long term good results. This study was undertaken to record changes in radiological parameters and its effect on the functional outcomes in first two years following HTO done for varus degenerative OA kneeby hemicallotasis technique using HTO fixator.

METHODS

31 patients meeting our inclusion-exclusion criteria who underwent HTO by hemicallotasis method using self-adjusting unilateral HTO fixator were included in the study. Their femoro tibial angle (FTA), mechanical axis %, Insall- Salvati ratio, proximal tibial antero-posterior slope and knee injury and osteoarthritis outcome Score (KOOS) were recorded preoperatively, postoperatively at the time of removal of fixator, at 1 year and at 2 years.

RESULTS

The FTA and mechanical axis significantly improved from a mean of 183.12⁰ and -3.26% respectively preoperatively to 173.38⁰ and 61.81% at the time of removal of fixator but subsequently showed significant deterioration to 176.06⁰ and 57.96% at 1 year and further insignificant deterioration to 176.16⁰ and 57.74 at 2 years. The KOOS improved from mean 56.61 preoperatively to 70.48 at the time of fixator removal and further improved significantly to 85.68 at 1 year but significantly deteriorated to 84.54 at 2 years. The Insall-Salvati ratio, tibial slope showed no significant change throughout the study. Conclusion: Though desired alignment can be achieved by using the fixator, we found a significant deterioration in achieved radiological parameters after removal of fixator adversely affecting the functional outcome which is a matter of concern.

Mid-term CT assessment of bone healing after nanohydroxyapatite augmentation in open-wedge high tibial osteotomy

BACKGROUND

The aim of the present study was to confirm the effectiveness of adding nanohydroxyapatite (NHA) to a heterologous bone graft in open-wedge high tibial osteotomy (OWHTO) by measuring the bone density via multislice computed tomography (CT) of the tibial osteotomy gap in a mid-term follow-up (five years).

METHODS

Twenty-six patients undergoing OWHTO were randomly assigned to two groups: a pure graft group (Group A), in which the osteotomy gap was filled with only heterologous bone graft, and an NHA group (Group B), in which the osteotomy gap was filled with heterologous bone graft and NHA. CT was performed within one week of the operation, after two months, after 12 months and after five years. CT volume acquired in Hounsfield units (HU) was measured on three planes.

RESULTS

The normal bone density was 110.2 ± 11.7 HU. The value of mean density at five years in Group A was 296.8 ± 81.8 HU, while in Group B, it was 202.2 ± 45.1 HU, showing a density more similar to normal bone and greater bone uniformity inside the osteotomy. The difference between the two groups was statistically significant (p < 0.05). Furthermore, both groups showed excellent mid-term clinical outcomes without significant differences.

CONCLUSIONS

This study revealed that absorbability and bone formation at the osteotomy site in the NHA group was significantly higher as compared with the pure graft group at five years postoperatively.

[Preoperative planning of constitutional varus alignment in patients with varus knees and coronal femoral lateral bowing]

Objective: To investigate the preoperative constitutional varus alignment (CA) inpatients withvarus osteoarthritic knees and coronal femoral lateral bowing (FLB) by comparing the femoral axis of the patients and volunteers' with straight femoral shaft (SFS) and healthy knees, which would be used to guide the selection of valgus correction angle(VCA) of distal femur in total knee anthroplasty (TKA). Methods: From January 2018 to December 2018, 45 nonconsecutive patients (90 knees) with varus osteoarthritic knees and obvious FLB (>5°) received primary TKA,and 50 limbs with healthy knees and SFS in 25 volunteers were studied at Xinqiao Hospital.The medial proximal femoral angle (MPFA) and anatomic lateral distal femoral angle (a-LDFA) were measured and compared between the two groups.The VCA formed by distal femoral mechanical axis (DMA) and distal femoral anatomic axis (DAA) in patients and the VCA based on neutral mechanical axis (NMA) in volunteers were also compared. The Pearson's correlation analysis was performed between the angle of bowing (α) and the VCA based on NMA in patients. The measurement data was compared with t test between the two groups. Results: The results showed that the MPFA and the a-LDFA were not significantly different between the volunteers with SFS and patients with FLB (MPFA:84.9°±3.7° vs 85.6°±1.8° and a-LDFA:81.7°±1.7° vs 81.2°±1.6°, t=1.26, 1.70, both P>0.05). The VCA based on NMA in volunteers with SFS was 5.5°±0.6°(4.5°-7.4°), the preoperative DAA-DMA angle was 5.3°±0.7°(4.3°-7.8°) in patients with FLB, there was no significant difference between the two groups (t=1.70, P=0.09). The angle of bowing (α) was 7.9°±2.9° (6°-16°), the VCA based on NMA was 8.4°±1.5°(5°-10°), there was a significantly positive correlation between VCA and α (R=0.607, P<0.01). Conclusion: There is no significantly proximal or distal femoral deformity in patients with varus osteoarthritic knee and FLB (>5°), the degree of the DMA-DAAangle based on the DMA doesn't change with the increasing angular deformity of the bowing, then the bowing would be reserved if the distal femur is cut based on DMA in TKA and the preoperative CA should be restored successfully.

Slight under-correction using individualized intentional varus femoral cutting leads to favorable outcomes in patients with lateral femoral bowing and varus knee

PURPOSE

Restoration of neutral alignment is considered key in total knee arthroplasty (TKA). However, this may be undesirable and can result in medial soft-tissue over-release in patients with varus knee and lateral femoral bowing. This study aimed to determine whether individualized intentional varus distal femoral cutting yielded satisfactory clinical and radiological outcomes.

METHODS

A total of 77 patients (91 knees) with varus knee (hip-knee-ankle axis ≥ 10°) and lateral femoral bowing > 5° underwent navigation-assisted primary TKA using individualized intentional varus distal femoral cutting. Knee Society scores, Western Ontario and McMaster Universities scores, and radiographs for limb alignment, implant alignment, and aseptic loosening were evaluated. Subgroup analyses were performed according to the limb alignment and coronal femoral component alignment (0° ± 3° vs. varus of > 3°).

RESULTS

All clinical outcomes significantly improved at the final follow-up (p < 0.05 in all). The mechanical axis angle changed from 13.1° ± 2.7° to 2.8° ± 1.5°. The coronal femoral component angle at the final follow-up was 2.8° ± 1.3°. Radiolucent lines were observed in 6 cases (6.6%) and were less than 2 mm in all cases without progression. In subgroup analyses, no significant differences were observed in clinical outcomes (n.s. in all) and in the incidence of radiolucent lines (n.s. in limb alignment, n.s. in coronal femoral component alignment).

CONCLUSIONS

Individualized intentional varus distal femoral cutting yielded favorable clinical outcomes without complications at 5-year follow-up. Slight under-correction using intentional varus distal femoral cutting could be a viable option in patients with varus knee and lateral femoral bowing during navigation-assisted TKA.

LEVEL OF EVIDENCE

IV.

Improving the accuracy of tibial component placement during total knee replacement in varus knees with tibial bowing: A prospective randomised controlled study

BACKGROUND

Lateral tibial bowing leads to varus placement of the tibial component during total knee replacement in varus knees. Lateralised tibial jig placement can improve the accuracy of the tibial cut.

METHODS

A total of 227 patients (300 knees) undergoing total knee replacements were randomised into two groups. In the study group, the point of intersection of the distal tibial diaphyseal line at the tibial plateau drawn on long films was represented by zones. Knees with femoral bowing >5° (28%) were excluded. Tibial jig placement on the proximal tibia was lateralised according to the zones. In the control group, the mid-point of the tibial plateau was taken as a reference. Femoral and tibial bowing, postoperative limb alignment and component placement were assessed.

RESULTS

Of the 216 knees that were studied, 106 were in the study group and 110 in the control group. Bowing ≥3° had a significant positive correlation with lateralisation of the proximal tibial reference (p < 0.001). The Incidence of tibial bowing ≥3° was 57.33%. The mean postoperative hip-knee-ankle (HKA) angle was 178.31 ± 2.88° and 176.53 ± 2.88° (p < 0.001), whereas the mean medial proximal tibial angle (MPTA) was 89.91 ± 1.42° and 88.79 ± 1.72° (p < 0.001) in the study and control groups, respectively. Considering bowed tibiae alone, HKA angle and MPTA in the study group were 178.08 ± 2.81° and 89.72 ± 1.39° compared with 175.88 ± 2.87° and 88.38 ± 1.38° in the control group (p < 0.001).

CONCLUSION

There is a high incidence of tibial bowing in varus knees. Lateralised tibial jig placement improved tibial component placement and postoperative limb alignment in total knee arthroplasty in varus knees with tibial bowing.

The native coronal orientation of tibial plateaus may limit the indications to perform a kinematic aligned total knee arthroplasty

PURPOSE

To investigate the coronal alignment of tibial plateaus in normal and osteoarthritic knees and to simulate the effects of a tibial cut performed in total knee arthroplasty (TKA) using a kinematic alignment technique with standard instrumentation.

METHODS

The coronal alignment of tibial plateaus was measured in three groups including group 1 (reference group), 50 cadaveric tibiae showing no evidence of degenerative changes of tibial plateaus; group 2, 49 patients who underwent MR of the knee, showing no or mild degenerative changes of the knee joint and, group 3, 54 patients with knee osteoarthritis who underwent computer-assisted total knee arthroplasty.

RESULTS

The coronal alignment of tibial plateaus averaged 2.4° with no significant differences between groups. The mean coronal orientation of tibial plateaus was 3° ± 2° in men and 1.6° ± 2° in women (p = 0.03). A coronal alignment of tibial plateaus of 3° or more was found in 69 cases (45%) and 5° or more in 23 (14.7%). The simulation of a tibial cut performed with an error of 3° in varus in 15% of the subjects showing a native coronal orientation of tibial plateaus of 3° or more, led to a final tibial cut greater 6° in 13.7% of cases.

CONCLUSIONS

A coronal alignment of tibial plateaus of 3° or more in varus was found in near half of normal subjects and osteoarthritic patients. A preoperative measurement of the coronal alignment of tibial plateaus is advisable in any patients scheduled for kinematic aligned TKA. As errors in the alignment of the tibial component of 3° or more may occur using standard instrumentations, the results of this study raise questions on performing a kinematic aligned TKA with standard instrumentations.

LEVEL OF EVIDENCE

IV.

Residual medial tightness in extension is corrected spontaneously after total knee arthroplasty in varus knees

PURPOSE

Although soft tissue balancing is considered important for successful total knee arthroplasty (TKA), it is unclear whether the laxity and balance achieved intraoperatively change postoperatively. A recent study demonstrated anaesthesia significantly influenced knee joint laxity after TKA; however, there has been no comparison of the varus-valgus laxity immediately after TKA and in the postoperative period under the same anesthetic conditions. Therefore, quantitative stress arthrometric studies were conducted under identical conditions to identify changes in coronal ligament laxity after TKA spontaneously.

METHODS

A consecutive series of 28 knees with varus of more than 5° in 28 patients undergoing staged bilateral TKAs was prospectively evaluated. Postoperative varus-valgus laxity was measured immediately after surgery, with the patient still under spinal anaesthesia; and again at the time of the contralateral TKA, again under anaesthesia. The mean time between the first and second operations was 9.7 ± 7.3 months.

RESULTS

Mean medial laxity significantly changed from 2.4° ± 1.6° just after the first operation under anaesthesia to 3.8° ± 1.4° just after contralateral TKA under anaesthesia (p < 0.001), but no significant change occurred in lateral laxity (5.6° ± 2.4° just after the first operation and 5.7° ± 2.1° after contralateral TKA, n.s.). Significant negative correlations were identified between laxity immediately after surgery and the amount of laxity change on both the medial (R = - 0.63, p < 0.001) and lateral sides (R = - 0.53, p < 0.001).

CONCLUSION

Spontaneous soft tissue correction occurs after TKA. The findings from this study provides a rationale that it is not necessary for surgeons to perform the medial soft tissue release until the soft tissue tension is equalized on both the medial and lateral sides which has the risk of excessive release leading to instability. In situations where the surgeon is confronted with a knee that becomes too tight or too loose depending on the insert thickness, it is recommended to choose the thicker insert with the understanding that the knee will initially have a slightly tighter medial compartment that will loosen over time. The results of this study provide technical considerations that can help a surgeon achieve adequate postoperative stability.

LEVEL OF EVIDENCE

IV.

Comparison of navigated and conventional high tibial osteotomy for the treatment of osteoarthritic knees with varus deformity: A meta-analysis

BACKGROUND

High tibial osteotomy (HTO) is a usefully surgical procedure to correct the malalignment and delay the progression of osteoarthritis. It is still controversy whether navigation system can offer more accuracy of targeted alignment and achieve better clinical outcomes than conventional method. The purpose of present meta-analysis was to investigate whether navigation system was superior to conventional method with regard to clinical and radiographic outcomes.

METHOD

The included studies compared the clinical and radiographic outcomes between navigated HTO group and conventional group. The clinical assessments were Lysholm Score, AKS Function Score and Arc of motion, and the radiographic outcomes were Mechanical axis (MA), Weight bearing line ratio (WBL), Outliers of alignment and Change in TPS used to evaluate alignment correction. The meta-analysis was performed using Review Manager 5.3 software. Downs and Black and the Newcastle-Ottawa Scale (NOS) were used to evaluate the study quality.

RESULT

Sixteen studies were eligible in present meta-analysis, including thirteen studies concerning opening wedge HTO and three studies involving closing wedge HTO. Clinical outcomes were only reported in studies which used opening wedge HTO. No significant differences were observed in all clinical outcomes between navigated and conventional HTO. Regarding radiographic outcomes, no significant difference in WBL ratio was observed between navigated and conventional HTO. Patients undergoing navigated HTO were associated with significantly greater in MA and lower in Outliers of alignment compared with those undergoing conventional HTO. Compared with conventional HTO, increase in TPS was significantly lower in navigated HTO group using opening wedge HTO, but decrease in TPS was significantly greater in navigated HTO group using closing wedge HTO.

CONCLUSION

Our meta-analysis demonstrated that navigated HTO offered more accuracy and precision of alignment correction, except WBL ratio. However, better clinical outcomes were not observed in navigation group.

Selective medial soft tissue release combined with tibial reduction osteotomy in total knee arthroplasty

BACKGROUND

To obtain the correct coronal alignment and balancing in flexion and extension, we established a selective medial release technique and investigated the effectiveness and safety of the technique during primary total knee arthroplasty (TKA).

METHODS

Four hundred sixty-six primary TKAs with varus deformity were prospectively evaluated between June 2013 and June 2015. A knee joint position similar to Patrick's sign was used to release the medial structure. The medial release technique consisted of release of the capsule and the deep medial collateral ligament (dMCL) (step1), selective release of superficial medial collateral ligament (sMCL) or posterior oblique ligament (POL) (step 2), and selective tibial reduction osteotomy (step 3). Improvement of medial joint gap at each step and other clinical outcomes were evaluated.

RESULTS

Among the 466 knees, symmetrical gaps could be achieved by the limited release of the capsule and the dMCcL in 276 (59%) knees. One hundred fifty-two (33%) required additional sMCL release with 2-5 cm from the joint line distally or POL release. Thirty-eight (8%) necessitated an additional tibial reduction osteotomy. Anterior-medial release and 4-mm medial osteotomy contributed to more improvement of medial gap in flexion than in extension (each p < 0.01). Posteromedial release and posteromedial osteotomy contributed to more improvement in extension than in flexion (each p < 0.01). No specific complication related to our technique was identified.

CONCLUSION

The technique of the tibial reduction osteotomy combined with medial soft structure release using Patrick's sign is effective, safe, and minimally invasive to obtain balanced mediolateral and extension-flexion gaps in primary TKA.

Good functional results following high tibial opening-wedge osteotomy of knees with medial osteoarthritis: A prospective study with a mean of 8.3years of follow-up

BACKGROUND

To report time dependent functional improvement and predictive risk factors for failure when the load in varus knees with medial osteoarthritis is shifted from the medial to the lateral knee compartment.

METHODS

Forty-nine consecutive patients (52 knees), mean age 47 (31-64) years, underwent a high tibial opening-wedge valgus osteotomy stabilized with a Puddu plate and bone grafting. The patients were evaluated with the Knee Injury and Osteoarthritis Outcome Score (KOOS) preoperatively and at three and six months, one, two, five and 10years postoperatively with a mean follow-up time of 8.3years (2.0-10.6).

RESULTS

Mean angular correction was 8.0° (four to 12). The five subscores of KOOS increased significantly during the first year by 40-131% from preoperative values, the good results remaining throughout the 10-year follow-up for those with a surviving osteotomy. The outcome was related to the grade of preoperative osteoarthritis. Seven knees were converted to total knee arthroplasty (TKA) mean 6.2years (two to nine) post-operatively, and had a lower KOOS preoperatively than those of surviving osteotomies. The osteotomy survival rate at five years was 94% and at 10years 83%. Patients with KOOS subscore quality of life (QoL) <44 at the two-year follow-up had a 11.7 times higher risk for later TKA than those with QoL ≥44 (P=0.017).

CONCLUSION

High tibial opening-wedge osteotomy for medial knee osteoarthritis resulted in good functional recovery after one year and favorable mid-term results. It may be a good treatment option for middle-aged patients with varus knees and medial osteoarthritis in order to prevent or postpone TKA.

The pie-crusting technique using a blade knife for medial collateral ligament release is unreliable in varus total knee arthroplasty

PURPOSE

Despite the documented clinical efficacy of the pie-crusting technique for medial collateral ligament (MCL) release in varus total knee arthroplasty, its quantitative effects on medial gaps and safety remain unclear. This study was undertaken to determine the efficacy (quantitative effect and consistency of the number of punctures) and the safety (frequency of early over-release) of the pie-crusting technique for MCL release.

METHODS

From ten pairs of cadaveric knees, one knee from each pair was randomly assigned to undergo pie crusting in extension (group E) or in flexion (group F). Pie crusting was performed in the superficial MCL using a blade until over-release occurred. After every puncture, the incremental medial gap increase was recorded, and the number of punctures required for 2- or 4-mm gap increases was assessed.

RESULTS

In group E, the extension gap increased from 0.8 to 5.0 mm and the flexion gap increased from 0.8 to 3.0 mm. In group F, the extension gap increased from 1.0 to 3.0 mm and the flexion gap increased from 2.6 to 6.0 mm. However, the gap increments were inconsistent with those that followed the preceding blade punctures, and the number of punctures required to increase the gaps by 2 or 4 mm was variable. The number of punctures leading to over-release in group E and group F was 6 ± 1 and 3 ± 1 punctures, respectively. Overall, 70% of over-release occurred earlier than the average number of punctures leading to over-release.

CONCLUSIONS

Pie crusting led to unpredictable gap increments and to frequent early over-release. Surgeons should decide carefully before using the pie-crusting technique for MCL release and should be cautious of performing throughout the procedure, especially when performing in a flexed knee.

LEVEL OF EVIDENCE

Therapeutic study, Level I.

Correlation between varus knee malalignment and patellofemoral osteoarthritis

PURPOSE

To evaluate the relationship between patellofemoral osteoarthritis (OA) and varus OA of the knee with a focus on the location of joint space narrowing.

METHODS

Eighty-five patients scheduled to undergo total knee arthroplasty caused by varus OA were enrolled in this study. The relationship between patellofemoral OA and varus knee malalignment was elucidated. To determine the alignment of the patellofemoral joint in varus knees, patellar tilt, and the tibial tuberosity-trochlear groove (TT-TG) distance were measured, and patellofemoral OA was classified using computed tomography.

RESULTS

The femorotibial angles in patients with stage II-IV patellofemoral OA were significantly larger than those in patients with stage I patellofemoral OA, and the patellar tilt in patients with stage II-IV patellofemoral OA and the TT-TG distance in patients with stage IV patellofemoral OA were significantly larger than those in patients with stage I patellofemoral OA. The TT-TG distance was strongly correlated with patellar tilt (R(2) = 0.41, P < 0.001). Patellofemoral joint space narrowing was mainly noted at the lateral facet, and it was found on both sides as patellofemoral OA worsened.

CONCLUSION

Varus knee malalignment was induced by patellofemoral OA, especially at the lateral facet. Patellar tilt and the TT-TG distance are considered critical factors for the severity of patellofemoral OA. Understanding the critical factors for patellofemoral OA in varus knees such as the TT-TG distance and patellar will facilitate the prevention of patellofemoral OA using procedures such as high tibial osteotomy and total knee arthroplasty to correct knee malalignment.

LEVEL OF EVIDENCE

Retrospective cohort study, Level III.

Effects of a novel foot-ankle orthosis in the non-operative treatment of unicompartmental knee osteoarthritis

INTRODUCTION

Unloader braces are non-surgical treatment options for patients with unicompartmental knee osteoarthritis (OA). However, many patients do not adhere to brace treatment because of complications related to discomfort and poor fit. An alternative to knee bracing is an ankle-foot orthosis (AFO) with a lever arm that presses the lower leg into valgus or varus. The aim of this study is to evaluate the clinical benefits of this AFO for patients with unicompartmental knee OA.

MATERIALS AND METHODS

Twenty-three patients with knee OA were enrolled in this observational study. The primary clinical outcome measure was the Western Ontario and McMasters Universities Arthritis Index (WOMAC) total score. Secondary outcome measures included WOMAC subscores, visual analogue pain scale, activity restriction and complication rate. Clinical scores were collected at start and 3, 6, 9, and 12 months after enrollment. Statistical evaluation was performed using the Student's t test.

RESULTS

Of the patients enrolled, 83 % suffered from medial compartment OA. Most patients had Grade II OA according to the Kellgren and Lawrence classification. WOMAC total score, both subscores and visual analogue pain scale were significantly improved over time. Patients also noted a reduction in restrictions to activities of daily living and sport-related activities while using the AFO. No patients discontinued orthosis use because of adverse effects. Two types of complications were noted: discomfort or light pressure sores around the ankle (7 patients), and wear and tear of the shoe in which the AFO was worn (14 patients).

CONCLUSIONS

This observational study suggests that this AFO is effective at significantly reducing pain and stiffness as well as improving the physical function of patients with mild to moderate unicompartmental osteoarthritis of the knee.

Comparison of complete distal release of the medial collateral ligament and medial epicondylar osteotomy during ligament balancing in varus knee total knee arthroplasty

Background

During ligament balancing for severe medial contracture in varus knee total knee arthroplasty (TKA), complete distal release of the medial collateral ligament (MCL) or a medial epicondylar osteotomy can be necessary if a large amount of correction is needed.

Methods

This study retrospectively reviewed 9 cases of complete distal release of the MCL and 11 cases of medial epicondylar osteotomy which were used to correct severe medial contracture. The mean follow-up periods were 46.5 months (range, 36 to 78 months) and 39.8 months (range, 32 to 65 months), respectively.

Results

There were no significant differences in the clinical results between the two groups. However, the valgus stress radiograph revealed significant differences in medial instability. In complete distal release of the MCL, some stability was obtained by repair and bracing but the medial instability could not be removed completely.

Conclusions

Medial epicondylar osteotomy for a varus deformity in TKA could provide constant medial stability and be a useful ligament balancing technique.