Osteotomies around the knee lead to corresponding frontal realignment of the ankle

Assessment and quantification of ipsilateral and contralateral ankle joint alignment changes after unilateral total knee arthroplasty for knee osteoarthritis with varus deformity: a retrospective cohort study

PURPOSE

The study's primary objective was to assess and quantify the ipsilateral (side A) and contralateral (side B) ankle joint line orientation (AJLO) changes after unilateral total knee arthroplasty (TKA) for primary knee osteoarthritis (OA) with varus deformity. The secondary objectives were to detect if there was a correlation between the knee deformity correction and AJLO changes and if the knee and ankle clinical outcomes on the TKA side correlate with joint alignment changes.

METHODS

This retrospective cohort study included 70 patients with a mean age of 61.76 ± 5.96 years. The lower limb alignment was evaluated using the hip-knee-ankle (HKA) angle, while the AJLO was assessed using the tibial plafond to horizontal line angle (TPHA). The functional outcomes for side A were evaluated at a median follow-up of 18 (interquartile range (IQR): 12-46.2) months using the Knee Injury and Osteoarthritis Outcome Score (KOOS) and The American Orthopaedic Foot and Ankle Society (AOFAS) score for the knee and ankle joints, respectively.

RESULTS

In side A, the HKA significantly improved from 167.49 ± 6.25 to 177.08 ± 4.39 (p < 0.001). No difference in AJLO was found between both sides preoperatively (p = 0.329). At the last follow-up, in side A, the AJLO changed significantly into less varus from -7.11 ± 5.44° to -1.10 ± 4.91° (p < 0.001); in side B, the AJLO showed no significant changes (-6.38 ± 6.10° versus -6.65 ± 6.50°, p = 0.970). For side A, the KOOS and AOFAS showed significant improvement, 45.20 ± 14.94 versus 75.72 ± 13.28 (p < 0.001) and 70 (65-75) versus 90 (80-90; p < 0.001), respectively. The preoperative HKA and AJLO on side A and side B showed significant positive correlations (r = 0.591, p < 0.001 and r = 0.611, p < 0.001, respectively). On side A, the postoperative HKA and AJLO showed a significant positive correlation (r = 0.298, p = 0.012). The preoperative and postoperative AJLO and AOFAS on side A showed nonsignificant negative correlations (r = -0.202, p = 0.277 and r = -0.115, p = 0.537, respectively). The preoperative and postoperative HKA and AOFAS on side A showed nonsignificant positive correlations (r = 0.126, p = 0.499 and r = 0.331, p = 0.069, respectively). The linear regression analysis indicated that for every 1° correction in HKA, the AJLO changed by 0.5° (R2 = 0.241, 95% confidence interval (CI) 0.298-0.747, p < 0.001).

CONCLUSIONS

The ipsilateral ankle joint realigned to a less varus position after ipsilateral TKA for managing knee OA with varus deformity, with an estimated half a degree of less varus AJLO after HKA correction by a degree. No changes occurred in the contralateral ankle joint. The ankle joint function improvement was not correlated to the HKA or AJLO changes.

Knee osteotomies significantly influence coronal ankle alignment: A radiographic analysis

Purpose

This study aimed to evaluate the effect of lateral closing-wedge high tibial osteotomy (LCW-HTO) and medial closing-wedge distal femoral osteotomy (MCW-DFO) on tibio-talar inclination (TTI) and Mikulicz lateral distal tibial angle (M-LDTA). We hypothesized that knee osteotomies significantly alter ankle coronal alignment by modifying TTI and distal tibial alignment in relation to the mechanical axis.

Methods

A retrospective radiographic analysis was conducted on 60 knees from 52 patients (37 LCW-HTO and 23 MCW-DFO) treated between 2006 and 2020. Inclusion criteria included full-length weight-bearing radiographs pre- and post-operatively, no prior ipsilateral lower limb surgery, absence of shaft deformities or advanced ankle osteoarthritis (Takakura grade >1), and age ≥16 years with ≥2 years of follow-up. Radiographic parameters measured included LDTA, hip-knee-ankle angle, M-LDTA and TTI, with ankle realignment quantified through differences between LDTA and M-LDTA and between pre- and post-operative TTI.

Results

In the MCW-DFO group, the difference between LDTA and M-LDTA decreased from 3.5 ± 2.3° to 1.3 ± 1.1° (p < 0.0001), indicating improved alignment. The LCW-HTO group showed a smaller but significant reduction from 4.5 ± 1.8° to 2.2 ± 1.7° (p < 0.0001). TTI improved significantly in both groups, with a greater adjustment in MCW-DFO (ΔTTI = 7.0 ± 4.3°, p < 0.01) compared to LCW-HTO (ΔTTI = 4.2 ± 2.7°, p < 0.01). The difference between LDTA and TTI decreased in both groups, reflecting post-operative convergence of the mechanical and anatomical axes.

Conclusion

Knee osteotomies significantly influence ankle coronal alignment, particularly modifying TTI and M-LDTA. Higher-level osteotomies (MCW-DFO) exert a greater effect on ankle alignment than LCW-HTO. Preoperative valgus or varus knee deformities must be carefully evaluated to anticipate post-operative ankle imbalance. Surgeons should assess full-length radiographs to prevent unintended malalignment.

Level of Evidence

Level III.

Development of an automatic surgical planning system for high tibial osteotomy using artificial intelligence

BACKGROUND

This study proposed an automatic surgical planning system for high tibial osteotomy (HTO) using deep learning-based artificial intelligence and validated its accuracy. The system simulates osteotomy and measures lower-limb alignment parameters in pre- and post-osteotomy simulations.

METHODS

A total of 107 whole-leg standing radiographs were obtained from 107 patients who underwent HTO. First, the system detected anatomical landmarks on radiographs. Then, it simulated osteotomy and automatically measured five parameters in pre- and post-osteotomy simulation (hip knee angle [HKA], weight-bearing line ratio [WBL ratio], mechanical lateral distal femoral angle [mLDFA], mechanical medial proximal tibial angle [mMPTA], and mechanical lateral distal tibial angle [mLDTA]). The accuracy of the measured parameters was validated by comparing them with the ground truth (GT) values given by two orthopaedic surgeons.

RESULTS

All absolute errors of the system were within 1.5° or 1.5%. All inter-rater correlation confidence (ICC) values between the system and GT showed good reliability (>0.80). Excellent reliability was observed in the HKA (0.99) and WBL ratios (>0.99) for the pre-osteotomy simulation. The intra-rater difference of the system exhibited excellent reliability with an ICC value of 1.00 for all lower-limb alignment parameters in pre- and post-osteotomy simulations. In addition, the measurement time per radiograph (0.24 s) was considerably shorter than that of an orthopaedic surgeon (118 s).

CONCLUSION

The proposed system is practically applicable because it can measure lower-limb alignment parameters accurately and quickly in pre- and post-osteotomy simulations. The system has potential applications in surgical planning systems.

Optimal Sequence of Corrective Surgeries for Concomitant Valgus Knee and Rigid Pes Planus Deformities: The Knee-First Approach

In patients requiring surgical correction of ipsilateral valgus knee and rigid pes planovalgus deformities, the optimal operative sequence is controversial. Growing evidence suggests these 2 deformities are related in etiology and interrelated in disease course. We present the case of a 72-year-old female with concomitant valgus knee and rigid pes planovalgus deformities successfully treated with total knee arthroplasty followed by triple arthrodesis and Achilles lengthening. Surgical correction of these deformities must be carefully planned between the operating surgeons to avoid over- or under-correction of alignment that could further impact gait. In contrast with the limited available literature, the authors recommend correction at the knee first and the foot and ankle second. Further prospective studies are needed to elucidate the best operative sequence in these patients.

Osteotomies around the knee alter alignment of the ankle and hindfoot: a systematic review of biomechanical and clinical studies

Purpose

Emerging reports suggest an important involvement of the ankle/hindfoot alignment in the outcome of knee osteotomy; however, a comprehensive overview is currently not available. Therefore, we systematically reviewed all studies investigating biomechanical and clinical outcomes related to the ankle/hindfoot following knee osteotomies.

Methods

A systematic literature search was conducted on PubMed, Web of Science, EMBASE and Cochrane Library according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered on international prospective register of systematic reviews (PROSPERO) (CRD42021277189). Combining knee osteotomy and ankle/hindfoot alignment, all biomechanical and clinical studies were included. Studies investigating knee osteotomy in conjunction with total knee arthroplasty and case reports were excluded. The QUality Appraisal for Cadaveric Studies (QUACS) scale and Methodological Index for Non-Randomized Studies (MINORS) scores were used for quality assessment.

Results

Out of 3554 hits, 18 studies were confirmed eligible, including 770 subjects. The minority of studies (n = 3) assessed both high tibial- and distal femoral osteotomy. Following knee osteotomy, the mean tibiotalar contact pressure decreased (n = 4) except in the presence of a rigid subtalar joint (n = 1) or a talar tilt deformity (n = 1). Patient symptoms and/or radiographic alignment at the level of the ankle/hindfoot improved after knee osteotomy (n = 13). However, factors interfering with an optimal outcome were a small preoperative lateral distal tibia angle, a small hip-knee-ankle axis (HKA) angle, a large HKA correction (>14.5°) and a preexistent hindfoot deformity (>15.9°).

Conclusions

Osteotomies to correct knee deformity alter biomechanical and clinical outcomes at the level of the ankle/hindfoot. In general, these changes were beneficial, but several parameters were identified in association with deterioration of ankle/hindfoot symptoms following knee osteotomy.

The gap height in open wedge high tibial osteotomy is not affected by the starting point of the osteotomy

INTRODUCTION

In open-wedge high-tibial-osteotomy (OWHTO), most surgeons use a preoperative planning software and realise that they should match the intraoperative alignment correction with the preoperative plan. We aimed to determine whether there is a difference in osteotomy gap height when starting the OWHTO either 3 or 4 cm distal to the joint line. This should help to clarify whether the osteotomy starting point must exactly match the preoperative planning.

METHODS

25 patients with constitutional varus alignment were planned for OWHTO. Long-leg-standing-radiographs and mediCAD-software were used. Osteotomy was planned to a neutral Hip-Knee-Ankle angle (HKA) of 0°. The osteotomy-starting-point was either 3 or 4 cm distal to the medial joint line. The following angles were compared: mechanical medial proximal tibial angle (mMPTA), mechanical lateral distal femoral angle (mLDFA), joint line conversion angle (JCA), mechanical Tibio-Femoral angle (mTFA) or Hip Knee Ankle (HKA) angle.

RESULTS

25 Patients (18 males, 7 females) had a mean age of 62 ± 16.6 years and showed a varus-aligned leg-axis. The HKA was - 5.96 ± 3.02° with a mMPTA of 82.22 ± 1.14°. After osteotomy-planning to a HKA of 0°, the mMPTA was 88.94 ± 3.01°. With a mean wedge height of 8.08 mm when locating the osteotomy 3 cm and a mean wedge height of 8.05 mm when locating the osteotomy 4 cm distal to the joint-line, there was no statistically significant difference (p = 0.7).

CONCLUSION

When performing an OWHTO aiming towards the tip of the fibula, the osteotomy starting point does not need to exactly match the planned starting-location of the osteotomy. A starting-point 1 cm more distal or proximal than previously determined through the digital planning does not alter the size of the osteotomy gap needed to produce the desired amount of correction.

Effect of Medial Closing Wedge Distal Femoral Varization Osteotomy on Coronal Ankle and Hindfoot Alignment

BACKGROUND

To date, only a few studies have reported postoperative changes in coronal ankle alignment after valgus knee correction through medial closing wedge distal femoral varization osteotomy (MCWDFO). This study aimed to measure the changes of MCWDFO on coronal ankle and hindfoot alignment.

METHODS

We retrospectively reviewed the radiographic findings of 27 consecutive patients (34 cases) with knee valgus malalignment who underwent MCWDFO for either lateral knee joint osteoarthritis (OA) or recurrent patellar subluxation/dislocation (RPD). Several radiographic parameters were measured and compared based on the reason for operation, followed by the status of preoperative hindfoot alignment (hindfoot alignment angle [HAA] > 4 degrees, varus; -4 degrees ≤HAA ≤ 4 degrees, neutral; HAA < -4 degrees, valgus) in each group.

RESULTS

Overall, pre- and postoperative hindfoot alignments were within the neutral alignment range and were not significantly changed after the operation (P > .05). Nineteen cases were for lateral knee OA and 15 were for RPD, respectively. In both groups, preoperative neutral hindfoot alignments accounted for the largest portion (52.6% in the lateral OA group; 80.0% in the RPD group). Postoperatively, regardless of the reason for operation, hindfoot alignments changed toward the neutral range in all subgroups (ie, no changes in the preoperative neutral group; increased in the valgus group; decreased in the varus group).

CONCLUSION

We recommend that surgeons leave the hindfoot untouched when they plan the MCWDFO to correct knee joint valgus malalignment concomitant with hindfoot valgus or varus deviation as the hindfoot malalignment appears to change toward the neutral range postoperatively.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

The Relationship between Frontal, Axial Leg Alignment, and Ankle Joint Line Orientation-a Radiographic Analysis of Healthy Subjects

OBJECTIVE

Ankle joint line orientation (AJLO) is influenced by the subtalar foot and frontal leg alignment. However, the influence of axial leg alignment on AJLO remains unclear. The study aimed to analyze the influence of frontal, axial leg alignment on AJLO in healthy subjects.

METHODS

Thirty healthy subjects (60 legs) without prior surgery underwent standing biplanar long leg radiograph (LLR) between 2016 and 2020. AJLO was measured in standing long-leg radiographs relative to the ground. Meary's angle and calcaneal pitch were measured. Hip-knee-ankle angle (HKA), femoral antetorsion, and tibial torsion were assessed with SterEOS software (EOS Imaging, Paris, France). LLR was acquired with the feet directing straight anteriorly, which corresponds to a neutral foot progression angle (FPA). The influence of subtalar, frontal, and axial alignment on AJLO was analyzed in a multiple regression model.

RESULTS

An increase in knee valgus increased relative valgus AJLO by 0.5° (95% CI: 0.2° to 0.7°) per 1° (P < 0.001). A decrease in femoral antetorsion increased relative valgus AJLO by 0.2° (95% CI: 0.1° to 0.2°) per 1° (P < 0.001), whereas Meary's angle and calcaneal pitch did not influence AJLO.

CONCLUSION

A link between frontal, axial leg alignment, and AJLO could be demonstrated, indicating that a valgus leg alignment and relative femoral retrotorsion are associated with an increase of valgus AJLO in healthy subjects when placing their feet in a neutral position. Alteration of the frontal, or rotational profile after realignment surgery or by implant positioning might influence the AJLO, when the FPA is kept constant.

Increasing grades of frontal deformities in knee osteoarthritis are not associated with ligamentous ankle instabilities

PURPOSE

Varus or valgus deformities in knee osteoarthritis may have a crucial impact on ankle subtalar range of motion (ROM) and ligamentous stability. The purpose of this study was to assess whether the grade of ankle eversion and inversion rotation stability was influenced by frontal deformities of the knee joint.

METHODS

Patients who were planned to undergo total knee arthroplasty (TKA) were prospectively included in this study. Patients were examined radiologically (mechanical tibiofemoral angle (mTFA), hindfoot alignment view angle (HAVA), anterior distal tibia angle (ADTA)) and clinically (ROM of the knee and ankle joint, foot function index, knee osteoarthritis outcome score). Ankle stability was assessed using an ankle arthrometer (AA) to test inversion/eversion (ie) rotation and anterior/posterior (ap) displacement stability of the ankle joint. Correlations were calculated using Pearson's coefficient, and differences between two independent groups of nonparametric data were calculated using a two-sided Wilcoxon signed rank test.

RESULTS

Eighty-two (varus n = 52, valgus n = 30) patients were included. The preoperative mTFA significantly correlated with the HAVA (Pearson's correlation = - 0.72, p < 0.001). Laxity testing of the ankle demonstrated that in both varus and valgus knee osteoarthritis, higher grades of mTFA did not correlate with the inversion or eversion capacity of the ankle joint. The ADTA significantly correlated with the posterior displacement of the ankle joint (cor = 0.24, p = 0.049).

CONCLUSIONS

This study could not confirm that higher degrees of frontal knee deformities in osteoarthritis were associated with increasing grades of ligamentous ankle instabilities or a reduced ROM of the subtalar joint.

LEVEL OF EVIDENCE

II.

Accuracy, inter- and intrarater reliability, and user-experience of high tibial osteotomy angle measurements for preoperative planning: manual planning PACS versus semi-automatic software programs

Purpose

To compare the accuracy, inter- and intrarater reliability, and user-experience of manual and semi-automatic preoperative leg-alignment measurement planning software for high tibial osteotomy (HTO).

Methods

Thirty patients (31 lower limbs) who underwent a medial opening wedge HTO between 2017 and 2019 were retrospectively included. The mechanical lateral distal femur angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and planned correction angle were measured on preoperative long-leg full weight-bearing radiographs utilising PACS Jivex Review® v5.2 manual and TraumaCad® v2.4 semi-automatic planning software. Independent measurements were performed by four raters. Two raters repeated the measurements. Accuracy in the standard error of measurement (SEM), inter- and intrarater reliability, and user-experience were analysed. Additionally, measurements errors of more than 3° were remeasured and reanalysed.

Results

The SEMs of all measured varus malalignment angles and planned correction angle were within 0.8° of accuracy for both software programs. Measurements utilising the manual software demonstrated moderate interrater intraclass correlation coefficient (ICC)-values for the mLDFA and mMPTA, and an excellent interrater ICC-value for the correction angle (0.810, 0.779, and 0.981, respectively). Measurements utilising the semi-automatic software indicated excellent interrater ICC-values for the mLDFA, mMPTA, and correction angle (0.980, 0.909, and 0.989, respectively). The intrarater reliability varied substantially per angle, presenting excellent intrarater agreements by both raters (ICC >  0.900) for the correction angle in each software program as well as poor-to-excellent ICC-values for the mLDFA (0.282–0.951 and 0.316–0.926) and mMPTA (0.893–0.934 and 0.594–0.941) in both the manual planning and semi-automatic software. Regarding user-experience, semi-automatic software was preferred by two raters, while the other two raters had no distinctive preference. After remeasurement of five outliers, excellent interrater ICC-values were found for the mLDFA (0.913) and mMPTA (0.957).

Conclusions

Semi-automatic software outperforms the manual software when user-experience and outliers are considered. However, both software programs provide similar performance after remeasurement of the human-related erroneous outliers. For clinical practice, both programs can be utilised for HTO planning.

Level of evidence

Diagnostic study, Level III.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40634-022-00475-x.

Iatrogenic ischiofemoral impingement due to high tibial osteotomy with overvalgization: a case report

Background

Open wedge high tibial osteotomy is a standard procedure for frontal realignment. It is indicated in varus knee with reduced mechanical medial proximal tibia angle. Overcorrection producing a mechanical medial proximal tibia angle out of the normal range (85–90°) is not recommended because this would lead to unphysiological joint-line orientation. Osteotomies around the knee also influence the adjacent ankle and hip joints. For the hip, it is known that frontal alignment of the leg influences the ischiofemoral space. A decreased ischiofemoral space can lead to painful impingement between the ischial bone and the lesser trochanter.

Case presentation

A 53-year-old German woman presented with severe ischiofemoral impingement symptoms and valgus malalignment of the left leg after open wedge high tibial osteotomy, which was indicated and performed by an orthopedic surgeon with intention to treat medial knee pain due to degenerative arthritis of the medial compartment years after medial meniscectomy. The mechanical medial proximal tibia angle was 100.5°. We performed closed wedge high tibial osteotomy producing a mechanical medial proximal tibia angle of 90.0° and normal joint-line orientation. The hip pain was gone immediately after the surgery, and the patient had no signs of ischiofemoral impingement or hip pain at last follow-up 12 months after closed wedge high tibial osteotomy.

Conclusions

Frontal realignment osteotomy around the knee can create problems at adjacent joints. Overvalgization of the proximal tibia made the patient compensate by hyperadduction of the hip to enable full foot sole contact with the floor. Hyperadduction of the hip decreased the ischiofemoral space, leading to severe impingement. Therefore, meticulous planning of osteotomies is important not to produce unphysiological situations or unwanted negative effects at the level of an adjacent joint.