Evaluation of postoperative orientation of the knee and ankle joint after open wedge high tibial osteotomy

Artificial intelligence-based assessment of leg axis parameters shows excellent agreement with human raters: A systematic review and meta-analysis

PURPOSE

The aim of this study was to conduct a systematic review and meta-analysis on the reliability and applicability of artificial intelligence (AI)-based analysis of leg axis parameters. We hypothesized that AI-based leg axis measurements would be less time-consuming and as accurate as those performed by human raters.

METHODS

The study protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO). PubMed, Epistemonikos, and Web of Science were searched up to 24 February 2024, using a BOOLEAN search strategy. Titles and abstracts of identified records were screened through a stepwise process. Data extraction and quality assessment of the included papers were followed by a frequentist meta-analysis employing a common effect/random effects model with inverse variance and the Sidik-Jonkman heterogeneity estimator.

RESULTS

A total of 13 studies encompassing 3192 patients were included in this meta-analysis. All studies compared AI-based leg axis measurements on long-leg radiographs (LLR) with those performed by human raters. The parameters hip knee ankle angle (HKA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibial angle (mMPTA), and joint-line convergence angle (JLCA) showed excellent agreement between AI and human raters. The AI system was approximately 3 min faster in reading standing long-leg anteroposterior radiographs (LLRs) compared with human raters.

CONCLUSION

AI-based assessment of leg axis parameters is an efficient, accurate, and time-saving procedure. The quality of AI-based assessment of the investigated parameters does not appear to be affected by the presence of implants or pathological conditions.

LEVEL OF EVIDENCE

Level I.

Joint-line obliquity angle is significantly affected by hip abduction and adduction: A simulated analysis

PURPOSE

Different methods for quantifying joint-line obliquity (JLO) have been described, including joint-line obliquity angle (JLOA), Mikulicz joint-line angle (MJLA) and medial proximal tibial angle (MPTA). The goal of the present study was to quantify the variation of JLOA based on the position of the hip. The hypothesis of our study is that JLO is significantly influenced by the abduction/adduction of the limb, unlike MJLA.

METHODS

One hundred long-leg-weightbearing X-rays were used. At time 0 and after 30 days, two observers performed different measurements, including (1) distance between pubic symphysis and center of the femoral head, (2) distance between center of the femoral head and center of the ankle joint, (3) distance between center of the ankle and medial malleolus, (4) hip-knee-ankle angle, (5) MPTA, (6) lateral distal femoral angle, (7) joint-line congruency angle, (8) JLOA, (9) MJL and (10) angle between Mikulicz line and line perpendicular to the ground. The changes of the JLOA based on the position of the hip (abducted, neutral, bipedal stance adduction and monopodal stance adduction) were calculated with trigonometric formulas and with simulation on an orthopaedic planning digital software.

RESULTS

The JLOA change between adducted and abducted positions was on average 12.8° (SD 0.9 mm). The MJL did not vary significantly based on hip position.

CONCLUSIONS

The adduction/abduction of the lower limb has a considerable impact on JLOA. Methods like MJLA which are not affected by hip position should be preferred for JLO evaluation.

LEVEL OF EVIDENCE

Level III, diagnostic study.

Osteotomy around the painful degenerative varus knee has broader indications than conventionally described but must follow a strict planning process: ESSKA Formal Consensus Part I

PURPOSE

The European consensus was designed with the objective of combining science and expertise to produce recommendations that would educate and provide guidance in the treatment of the painful degenerative varus knee. Part I focused on indications and planning.

METHODS

Ninety-four orthopaedic surgeons from 24 European countries were involved in the consensus, which focused on the most common indications for osteotomy around the knee. The consensus was performed according to an established ESSKA methodology. The questions and recommendations made were initially designed by the consensus steering group. And 'best possible' answers were provided based upon the scientific evidence available and the experience of the experts. The statements produced were further evaluated by ratings and peer review groups before a final consensus was reached.

RESULTS

There is no reliable evidence to exclude patients based on age, gender or body weight. An individualised approach is advised; however, cessation of smoking is recommended. The same applies to lesser degrees of patellofemoral and lateral compartment arthritis, which may be accepted in certain situations. Good-quality limb alignment and knee radiographs are a mandatory requirement for planning of osteotomies, and Paley's angles and normal ranges are recommended when undertaking deformity analysis. Emphasis is placed upon the correct level at which correction of varus malalignment is performed, which may involve double-level osteotomy. This includes recognition of the importance of individual bone morphology and the maintenance of a physiologically appropriate joint line orientation.

CONCLUSION

The indications of knee osteotomies for painful degenerative varus knees are broad. Part I of the consensus highlights the versatility of the procedure to address multiple scenarios with bespoke planning for each case. Deformity analysis is mandatory for defining the bone morphology, the site of the deformity and planning the correct procedure.

LEVEL OF EVIDENCE

Level II, consensus.

Preoperative joint line obliquity, a newly identified factor for overcorrection, can be incorporated into a novel preoperative planning method to optimise alignment in high tibial osteotomy

PURPOSE

The aim of this study was to analyse the factors associated with additional postoperative alignment changes after accurate bony correction by selecting only patients with well-performed bony correction as planned and develop a method of incorporating significant factors into preoperative planning.

METHODS

Among 104 consecutive patients who underwent medial open wedge high tibial osteotomy (MOWHTO) between October 2019 and July 2022, 61 with well-performed bony corrections were retrospectively reviewed. The major criterion for well-performed bony correction was a difference of <1° between the simulated medial proximal tibial angle (MPTA) and the actual postoperative MPTA as measured in three dimensions. Radiographic parameters, such as the joint line convergence angle (JLCA) and joint line obliquity (JLO), were measured preoperatively and postoperatively, utilising standing and supine whole lower extremity anteroposterior, valgus and varus stress radiographs. Multiple linear regression analysis identified the factors affecting alignment changes, and a prediction model was developed. A method for applying this prediction model to preoperative planning was proposed.

RESULTS

Preoperative JLCA on standing (preJLCAstd ), preoperative JLCA on 0° valgus stress radiograph (vgJLCA0 ), and preoperative JLO (preJLO) were significantly correlated with JLCA change (∆JLCA) (p < 0.001, p < 0.001, p = 0.006). The prediction model was estimated as ∆JLCA = 0.493 × (vgJLCA0 ) - 0.727 × (preJLCAstd ) + 0.189 × (preJLO) - 1.587 in. (R = 0.815, modified R2  = 0.646, p < 0.001). The proposed method resulted in a reduced overcorrection rate (p = 0.003) and an improved proportion of acceptable alignments (p = 0.013).

CONCLUSION

PreJLCAstd , vgJLCA0  and preJLO can be used to estimate ∆JLCA. PreJLO was recently identified as a significant factor associated with additional alignment changes. Utilising the proposed preoperative planning and a prediction model with these factors shows promise in calibrating postoperative alignment after MOWHTO.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Clinical relevance of joint line obliquity after high tibial osteotomy for medial knee osteoarthritis remains controversial: a systematic review

PURPOSE

To systematically review the literature on the association between knee joint line obliquity (KJLO) and clinical outcome after high tibial osteotomy (HTO) for medial knee osteoarthritis and summarize the KJLO cut-off value used when studying this association.

METHODS

A systematic search was conducted in three databases (PubMed, Embase, and Web of Science) on September 2022, updated on February 2023. Eligible studies describing postoperative KJLO in relation to clinical outcome after HTO for medial knee osteoarthritis were included. Nonpatient studies and conference abstracts without full-text were excluded. Two independent reviewers assessed title, abstract and full-text based on the inclusion and exclusion criteria. The modified Downs and Black checklist was used to assess the methodological quality of each included study.

RESULTS

Of the seventeen studies included, three had good methodological quality, thirteen fair quality, and one had poor quality. Conflicting findings were shown on the associations between postoperative KJLO and patient-reported outcome, medial knee cartilage regeneration, and 10-year surgical survival in sixteen studies. Three good-quality studies found no significant differences in lateral knee cartilage degeneration between postoperative medial proximal tibial angle > 95° and < 95°. Joint line orientation angles by the tibial plateau of 4° and 6°, joint line orientation angle by the middle knee joint space of 5°, medial proximal tibial angles of 95° and 98°, and Mikulicz joint line angle of 94° were KJLO cut-off values used in the included studies.

CONCLUSION

Based on current evidence, the actual association between postoperative KJLO and clinical consequences after HTO for medial knee osteoarthritis cannot be ascertained. The clinical relevance of KJLO after HTO remains controversial.

LEVEL OF EVIDENCE

IV.

Comparison of the plantar pressure distribution and mechanical alignment in patients with varus knee osteoarthritis following high tibial osteotomy

PURPOSE

The changes in the lower limb alignment were vitally important after high tibial osteotomy (HTO). Therefore, the purpose of present study was to analyze the characteristics of plantar pressure distribution after HTO, and to investigate the effect of plantar pressure distribution on postoperative limb alignment.

METHODS

Between May 2020 and April 2021, varus knee patients undergoing HTO were evaluated in the present study. The peak pressure of plantar regions, medial-lateral pressure ratio (MLPR), foot progression angle (FTA), anteroposterior COP (AP-COP), lateral symmetry of COP (LS-COP), and the radiographic parameters were evaluated preoperatively and at the final follow-up. Compared among the slight valgus (SV), moderate valgus (MV) and large valgus (LV) groups at the final follow-up, the peak pressure of HM, HC and M5 regions, and the MLPR were compared; the Knee Injury and Osteoarthritis Outcome Score4 (KOOS4) including four subscales, and the American of orthopedic foot and ankle society (AOFAS) were evaluated.

RESULTS

The WBL%, HKA and TPI angle changed significantly after HTO (P < 0.001). The preoperative group exhibited a lower peak pressure in the HM region (P < 0.05) and higher peak pressure in the M5 region (P < 0.05); the pre- and postoperative groups exhibited a lower peak pressure in the HC region (P < 0.05); the rearfoot MLPR was significantly lower and LS-COP was significantly higher in the preoperative group (P = 0.017 in MLPR and 0.031 in LS-COP, respectively). Comparison among the SV, MV and LV groups, the SV group indicated a lower peak pressure in the HM region (P = 0.036), and a lower MLPR in the rearfoot (P = 0.033). The KOOS Sport/Re score in the MV and LV groups increased significantly compared with the SV group (P = 0.042).

CONCLUSION

Plantar pressure distribution during the stance phase in patients with varus knee OA following HTO exhibited a more medialized rearfoot plantar pressure distribution pattern than that before surgery. Compared with the small valgus alignment, a moderate to large valgus alignment allows patients to walk with a more even medial and lateral plantar pressure distribution, which is more similar to healthy adults.