Osteotomy around the painful degenerative varus knee: a 2022 ESSKA formal consensus

Higher conversion rate to knee arthroplasty in female patients following medial open-wedge high tibial osteotomy

PURPOSE

Most studies about medial open-wedge high tibial osteotomy (HTO) reported outcomes without focusing on gender differences. Therefore, the study compared the long-term survival rate and postoperative subjective knee function after HTO in female versus male patients with symptomatic medial compartment knee osteoarthritis.

METHODS

The data of three cohorts with long-term outcomes were analysed (n = 245; 32% females; age: 49 ± 7 years; Kellgren Lawrence Grade I 6.1%, II 32.7%, III 42.4%; IV 18.8%). The minimum follow-up was at least 6 years or an earlier conversion to total knee arthroplasty (TKA). The gender-specific survival rate after HTO was calculated after 5 and 10 years and compared using Kaplan-Meier analysis and the logrank test. Baseline characteristics and subjective knee function (International Knee Documentation Committee [IKDC]/Lysholm) were analysed between both genders.

RESULTS

Forty of 78 (51.3%) women and 41 of 167 men (24.5%) underwent TKA. HTO survival in females was significantly lower (p = 0.0010). The 5- and 10-year survival rates were 85.9% and 62.6% for females and 93.4% and 77.7% for males. In females and males, from preoperative to the last follow-up, the IKDC (43 ± 15 to 58 ± 17; 47 ± 14 to 67 ± 18) and the Lysholm (42 ± 18 to 72 ± 18; 55 ± 22 to 77 ± 23) improved significantly (all p < 0.0001). Females had significantly lower preoperative and postoperative IKDC (p = 0.0438; p = 0.0035) and Lysholm scores (p = 0.0002; p = 0.0323). But the absolute improvements of the IKDC and Lysholm were not significantly different between genders.

CONCLUSIONS

Females had higher conversion rates to TKA and lower knee function at the last follow-up. However, preoperative knee function was lower in females and the absolute improvement following HTO was similar for both genders. In general, females benefit from HTO to treat medial knee arthritis, and TKA could be postponed for half of female patients for more than 10 years. However, surgeons must be aware of the described inferior outcomes in females for realistic patient expectation management.

LEVEL OF EVIDENCE

Level II.

Arthroscopic Centralization of the Medial Meniscus Reduces Load on a Posterior Root Repair Under Dynamic Varus Loading: A Biomechanical Investigation

BACKGROUND

In addition to the integrity of the meniscal hoop function, both the anterior and posterior meniscus roots as well as the meniscotibial and meniscofemoral ligaments are crucial in restraining meniscal extrusion. However, the interaction and load sharing between the roots and these peripheral attachments (PAs) are not known.

PURPOSES

To investigate the influence of an insufficiency of the PAs on the forces acting on a posterior medial meniscus root repair (PMMRR) in both neutral and varus alignment and to explore whether meniscal centralization reduces these forces.

STUDY DESIGN

Controlled laboratory study.

METHODS

In 8 fresh-frozen human cadaveric knees, an arthroscopic transosseous root repair (step 1) was performed after sectioning the posterior root of the medial meniscus. The pull-out suture was connected to a load cell to allow measurement of the forces acting on the root repair. A medial closing-wedge distal femoral osteotomy was performed to change the mechanical axis from neutral to 5° of varus alignment. The meniscus was completely released from its PAs (step 2), followed by transosseous arthroscopic centralization (step 3). Each step was tested in both neutral and varus alignment. The specimens were subjected to nondestructive dynamic varus loading under axial compression of 300 N in 0°, 15°, 30°, 45°, and 60° flexion. The changes in force acting on the PMMRR were statistically analyzed using a mixed linear model.

RESULTS

Axial loading in neutral alignment led to an increase of the force of root repair of 3.1 ± 3.1 N (in 0° flexion) to 6.3 ± 4.4 N (in 60° flexion). In varus alignment, forces increased significantly from 30° (3.5 N; 95% CI, 1.1-5.8 N; P = .01) to 60° (7.1 N; 95% CI, 2.7-11.5 N; P = .007) flexion, in comparison with neutral alignment. Cutting of the PAs in neutral alignment led to a significant increase of root repair forces in all flexion angles, from 7.0 N (95% CI, 1.0-13.0 N; P = .02) to 9.1 N (95% CI, 4.1-14.1 N; P = .003), in comparison with the intact state. Varus alignment significantly increased the forces in the cut states from 4.8 N (95% CI, 1.0-8.5 N; P = .02) to 11.1 N (95% CI, 4.2-18.0 N; P = .006) from 30° to 60° flexion, in comparison with the neutral alignment. Arthroscopic centralization led to restoration of the native forces in both neutral and varus alignment, with no significant differences between the centralized and intact states.

CONCLUSION

An insufficiency of the PAs of the medial meniscus, as well as varus alignment, led to increased forces acting on a PMMRR. These forces were reduced via an arthroscopic meniscal centralization.

CLINICAL RELEVANCE

Performing arthroscopic meniscal centralization concomitantly with PMMRR may reduce failure of the repair by reducing the load of the root.

Medial open wedge high tibial osteotomy is a viable option in young patients with advanced arthritis in a long-term follow-up

PURPOSE

This study aimed to evaluate the long-term outcomes of medial open wedge high tibial osteotomy (MOWHTO) as a treatment option for advanced medial compartment knee osteoarthritis (OA) Kellgren-Lawrence (K-L) III and IV.

METHODS

Patients with severe medial compartment arthritis, who underwent MOWHTO with locking plate between 2003 and 2015, were retrospectively reviewed. A locking plate for the osteotomy was utilized. Preoperative and postoperative patients' evaluation was performed using the International Knee Documentation Committee Score (IKDC), the Oxford Knee Score (OKS), the Knee Injury Osteoarthritis Outcome Score (KOOS) and the Short Form-12 Score (SF-12). Standardized standing whole-limb X-rays were taken to evaluate the mechanical tibiofemoral angle (mTFA) and proximal medial tibial angle (PMTA), and the severity of OA.

RESULTS

A total of 32 patients, 35 knees (27 males, five females) of which 21 were classified as K-L Grade III and 14 as K-L Grade IV, and mean age 47.1 ± 9.17 years old, who were followed for 13.6 years (range 7-20 years), were included in the study. During the follow-up period, three knees required conversion to total knee replacement (91.5% survival rate). All clinical outcome scores (KOOS, OKS, IKDC and SF-12) showed a significant improvement compared to preoperative status (p < 0.05). Preoperative mTFA and PMTA were significantly corrected immediately after surgery and retained this improvement at the last follow-up.

CONCLUSION

MOWHTO with a locking plate is an effective method to treat severe medial compartments. Clinical and radiological results are satisfactory and the survival rate is 91.5%, at a mean follow-up of 13.6 years after the procedure.

LEVEL OF EVIDENCE

Level IV.

Medial opening wedge high tibial osteotomy performs similarly irrespective of body mass index

PURPOSE

This study investigates the effect of the body mass index (BMI) on the early (2 years) to midterm (5 years) results of medial opening wedge high tibial osteotomy (MOWHTO).

METHODS

A prospectively maintained single-centre database of 1138 knee osteotomies, between 2002 and 2022, was retrospectively reviewed. Adult patients who underwent MOWHTO for symptomatic unicompartmental medial knee osteoarthritis (OA), with varus knee malalignment, having failed conservative management, were included. Patients were categorized into three groups according to their BMI as per the classification from the National Institute for Health and Care Excellence (NICE): the healthy weight (HW) group (BMI of 18.5-24.9 kg/m2), the overweight (OW) (BMI of 25-29.9 kg/m2), and the obesity (OB) group (BMI ≥ 30 kg/m2). Multiple patient-reported outcome measures (n = 6) were recorded preoperatively and at 2 and 5 years postoperatively. Deformity analysis was undertaken preoperatively and postoperatively. The relative risk (RR) of the complications between the HW, OW and OB groups was calculated. The rate of conversion to arthroplasty, and 5 and 10 years survivorship were recorded, as well as the hazard ratio (HR) of BMI on survivorship.

RESULTS

A total of 574 cases were included in the study: the HW group (n = 96), the OW group (n = 233) and the OB group (n = 245), with a mean BMI of 23 ± 1.5 kg/m2, 27.4 ± 1.4 kg/m2 and 34.4 ± 3.8 kg/m2, respectively. The mean follow-up was 13.3 years (4.8-20.3). The mean mechanical tibiofemoral angle corrections were in the HW group: 7.1 ± 3°, OW group: 6.6 ± 3.5° and OB group: 7.1 ± 3.8°, with no intergroup significant difference (p = n.s.). Clinically, despite lower preoperative scores in the OW and OB groups, no difference was observed postoperatively amongst the three groups. The overall complication rate was 12.5% in the HW group, 6.8% in the OW group, and 9.8% in the OB group. There was no significant difference in the RR of complications between the HW and OW groups (RR = 0.6, 95% confidence interval [CI] = 0.3-1.3) (p = 0.2), and the HW and OB groups (RR = 0.8; 95% CI = 0.3-2.2) (p = 0.7). There was no overall significant difference in survival outcomes based on the BMI between the three groups (p = 0.4). The HR of conversion to arthroplasty between the HW and OW groups was 1.4 [95% CI = 0.6-3.5](p = 0.5) and between the HW and OB groups was 1.8 [95% CI = 0.8-4.4] (p = 0.2).

CONCLUSION

BMI has no significant effect on either the radiological corrections, clinical outcomes, complications or survivorship of MOWHTO at short- to medium-term follow-up. No specific cutoff point for BMI can be recommended as a contraindication to MOWHTO.

LEVEL OF EVIDENCE

Level IV, Retrospective cohort study.

Around-the-knee osteotomies part 1: definitions, rationale and planning-state of the art

Knee osteotomies are essential orthopedic procedures with the ability to preserve the joint and correct ligament instabilities. Literature supports the correlation between lower limb malalignment and outcomes after knee ligament reconstruction and cartilage procedures. Concepts such as joint line obliquity, posterior tibial slope angle, and intra-articular deformity correction are integral components of both preoperative planning and postoperative evaluations. The concept of preserving and/or restoring joint line congruence during simultaneous correction of varus or valgus deformity can be achieved through several different approaches. With advancements in osteotomy research and surgical planning technology, the surgical decision-making has increased in complexity. Based upon a patient's specific deformity, decisions need to be made whether to perform a single-level (proximal tibia or distal femur) versus double-level (both proximal tibia and distal femur) osteotomy, and whether to correct deformity in a single plane (coronal or sagittal) or perform a biplanar osteotomy, correcting two of the malalignments in either coronal, sagittal, or axial planes. Osteotomy procedures prioritize safety, reproducibility, precision, and meticulous planning. Equally important is the proactive management of possible complications and the implementation of preventive strategies for complications such as hinge fractures and unintentional changes to alignment in other planes. This review navigates the intricate landscape of lower limb alignment, commencing with foundational definitions and rationale for performing osteotomies, progressing through the planning phase, and addressing the critical aspect of complication prevention, all while looking ahead to anticipate future advancements in this field. However, rotational osteotomies and tibial tubercle osteotomies in isolation or as an adjunct procedure are beyond the scope of this review.

Around-the-knee osteotomies part II: Surgical indications, techniques and outcomes - State of the art

Recent advances in surgical techniques and planning for knee-based osteotomies have led to improvements in addressing lower extremity malalignment. Part 1 of this review presented the biomechanical and clinical rationale of osteotomies, emphasizing the importance of osteotomies for restoring normal knee kinematics. In Part 2 of this review, indications, surgical technique and outcomes of osteotomies to correct coronal, sagittal and axial plane deformities will be examined. Traditional high tibial and distal femoral osteotomies will be discussed in addition to more recent advanced techniques including biplanar corrections and double-level osteotomies, as well as slope-correcting osteotomies. Patient-specific instrumentation and its use in more complex corrections will also be addressed.

Outcomes of Medial Closing-Wedge Distal Femoral Osteotomy for Femoral- and Tibial-Based Valgus Deformity

BACKGROUND

In carefully selected patients with an arthritic valgus knee, distal femoral osteotomy (DFO) can improve symptoms at medium- to long-term follow-up, reducing osteoarthritis progression. To date, there is no clear evidence in the current literature regarding the role of postoperative joint line obliquity (JLO) in valgus deformity correction.

PURPOSE

To assess the clinical and radiological outcomes of medial closing-wedge DFO (MCW-DFO) for the treatment of valgus knees, considering both tibial- and femoral-based deformities, as well as to verify the efficacy and safety of MCW-DFO according to JLO boundaries (≤4°).

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A retrospective analysis was conducted on a cohort of patients with valgus knees. Patients were divided into 2 groups: femoral-based valgus (FB-V) and tibial-based valgus (TB-V). Knee radiographs were collected before surgery and at the last follow-up. The clinical outcome was evaluated through several validated scores (International Knee Documentation Committee, Knee Society Score, Knee injury and Osteoarthritis Outcome Score, Tegner, Numeric Rating Scale, Crosby-Insall).

RESULTS

A total of 30 patients (34 knees) with a mean age of 49.3 ± 9.1 years were included in the study. The overall mean follow-up was 9.4 ± 5.9 years. The mean preoperative hip-knee-ankle angle was 187.6°± 3.3° (range, 181.5°-191°) and the postoperative angle was 180°± 3.1° (range, 176°-185°). Most postoperative JLOs were within the safe zone of ≤4° in both groups (the postoperative JLO was >4° in 4 patients in the TB-V group and 1 patient in the FB-V group), although FB-V knees exhibited significant superior JLO correction (postoperative JLO in the TB-V group: mean, 4.0°± 2.5° [P = .1]; postoperative JLO in the FB-V group: mean, 2.4°± 1.4° [P = .5]). Significant improvements in all clinical scores were observed in both groups (P < .01). Additionally, the severity of the osteoarthritis did not worsen at the last follow-up.

CONCLUSION

MCW-DFO is an effective procedure for treating pathological valgus knees, regardless of the site of the deformity. Both FB-V and TB-V groups showed comparable improvements in the clinical scores, development of osteoarthritis, and the restoration of a neutral mechanical axis. Notably, FB-V knees achieved more JLO correction compared with the TB-V ones.

Osteotomies for genu varum: Should we always correct at the tibia? A multicenter analysis of practices in France

INTRODUCTION

Tibial correction is often performed during a valgus-producing osteotomy for genu varum. However, overcorrection and the creation of a joint line obliquity (JLO) have been associated with unfavorable functional outcomes after high tibial osteotomy (HTO). The aims of this study were to analyze: 1) the corrections obtained after HTO; 2) the rationale behind the indication per the European Society for Sports Traumatology Surgery and Arthroscopy (ESSKA) recommendations; and 3) the correlation between the postoperative corrections obtained and functional outcomes.

HYPOTHESIS

A significant number of patients who underwent an isolated HTO did not present an "ideal" theoretical indication based on the preoperative angles and correction targets to be performed.

MATERIALS AND METHODS

This multicenter study included 289 isolated HTOs. Demographic and morphometric data were anonymized and compiled in a database. Preoperative radiographic parameters were compared with the ESSKA consensus recommendations on osteotomies for genu varum. The consensus defined the "ideal" indication for performing an HTO as medial tibiofemoral compartment pain with significant tibial varus deformity (medial proximal tibial angle [MPTA]<85°), no significant femoral varus deformity (lateral distal femoral angle [LDFA]<90°), an expected postoperative obliquity of less than 5°, and a correction resulting in moderate tibial valgus (postoperative MPTA<94°). The incidence of patients with an "ideal" theoretical indication for isolated HTO and those with a theoretical indication not perfectly justified by the radiographic data and preoperative planning were recorded.

RESULTS

Under the ESSKA consensus criteria, 25.3% (n=73) of isolated HTOs, 15.6% (n=45) of isolated femoral osteotomies, 9.3% (n=27) of double-level osteotomies, and 49.9% (n=144) of cases where no osteotomy was performed due to the lack of significant extra-articular tibial and/or femoral deformity were deemed justified. The presence of a preoperative femoral deformity and the absence of an "ideal" indication for HTO did not affect the postoperative Tegner Activity Scale or the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores (p>0.05). A high preoperative hip-knee-ankle (HKA) angle and MPTA, which indicated less varus, were associated with a greater risk of there being no "ideal" theoretical indication for an HTO (coefficient of determination [R2]=0.19 and R2=1, respectively; p<0.001).

CONCLUSION

This study showed that isolated HTOs in current practice were not justified in a significant number of patients, even though they could lead to tibial overcorrection and excessive JLO. This did not impact the functional results of this series, but it might complicate the performance of a secondary knee arthroplasty. Nevertheless, some young patients in this series underwent a salvage osteotomy outside the "ideal" indications of the European recommendations.

LEVEL OF EVIDENCE

IV; case series.

Closing wedge high tibial osteotomy: An old-fashioned technique? Survival, clinical and radiological outcomes of a case series analysis

INTRODUCTION

Closing wedge high tibial osteotomy (CW-HTO) is a surgical option for active patients with medial knee pain and mild-moderate osteoarthritis with varus limb deformity. Despite its good reported results, this technique has been losing popularity. The aim of this study was to analyse the survival rate, clinical functional outcomes and radiological results of CW-HTO.

METHODS

It is a retrospective case series study. Seventy patients with primary knee osteoarthritis, operated on between 2010 and 2020 in a single Spanish tertiary hospital using the CW-HTO technique and with a minimum follow-up of 2 years were analysed.

RESULTS

Survival rate was 87,6% and 75,5% after a follow-up of 5 and 10 years respectively. Functional outcomes were good-to-excellent (KSS 77.7/100 and OKS 35.6/48) and good pain control (VAS 3.9/10) and high satisfaction (7.2/10) were achieved. Limb varus malalignment was significantly corrected (mean postoperative HKA angle 177,6° and MPTA 90,7°). However, 30% of patients presented hypocorrection, which was associated with inferior survival, functionality and satisfaction.

CONCLUSION

CW-HTO technique can be useful for patients with knee osteoarthritis and varus limb. It allows to correct varus malalignment while achieving good-to-excellent functional outcomes, good pain control, high patient satisfaction and acceptable medium-long term survival rate. However, it is associated with a non-negligible risk of hypocorrection or medial hinge disruption.

[Translated article] Closing wedge high tibial osteotomy: An old-fashioned technique? Survival, clinical and radiological outcomes of a case series analysis

INTRODUCTION

Closing wedge high tibial osteotomy (CW-HTO) is a surgical option for active patients with medial knee pain and mild-moderate osteoarthritis with varus limb deformity. Despite its good reported results, this technique has been losing popularity. The aim of this study was to analyse the survival rate, clinical functional outcomes and radiological results of CW-HTO.

METHODS

It is a retrospective case series study. Seventy patients with primary knee osteoarthritis, operated on between 2010 and 2020 in a single Spanish tertiary hospital using the CW-HTO technique and with a minimum follow-up of 2 years were analysed.

RESULTS

Survival rate was 87.6% and 75.5% after a follow-up of 5 and 10 years respectively. Functional outcomes were good-to-excellent (KSS 77.7/100 and OKS 35.6/48) and good pain control (VAS 3.9/10) and high satisfaction (7.2/10) were achieved. Limb varus malalignment was significantly corrected (mean postoperative HKA angle 177.6° and MPTA 90.7°). However, 30% of patients presented hypocorrection, which was associated with inferior survival, functionality and satisfaction.

CONCLUSION

CW-HTO technique can be useful for patients with knee osteoarthritis and varus limb. It allows to correct varus malalignment while achieving good-to-excellent functional outcomes, good pain control, high patient satisfaction and acceptable medium-long term survival rate. However, it is associated with a non-negligible risk of hypocorrection or medial hinge disruption.

CPAK classification cannot be used to determine segmental coronal extra-articular knee deformity

PURPOSE

While the coronal plane alignment of the knee (CPAK) classification serves as a useful guide in personalising total knee arthroplasty (TKA), the extent of its correlation with segmental coronal extra-articular knee deformities remains uncertain. This study aims to investigate the potential correlation between CPAK matrix groups and segmental coronal extra-articular deformities in prearthritic knees, shedding light on the relationship between these two factors that seems to be both essential to perform personalised TKA.

MATERIALS AND METHODS

A radiological assessment of 1240 nonarthritic knees was performed by evaluating lower limb measurements following the protocol established by Paley et al. Subsequently, all knees were classified into their respective CPAK matrix groups. In our quest to discern any correlation between the CPAK matrix groups and the presence of segmental coronal extra-articular knee deformities, nine potential coronal extra-articular deformity phenotype (CEDP) groupswere identified based on medial proximal tibial angle (MPTA) and mechanical lateral distal femoral angle (mLDFA). Neutral values for MPTA and mLDFA were set at 90.0° ± 3.0° and then at 87.0° ± 2.0°. Each CPAK matrix group underwent detailed coronal morphology analysis and then, segmental coronal extra-articular deformities were assessed by comparing them with the CEDP groups.

RESULTS

The study revealed a mean hip-knee-ankle angle (HKA) of 178.6° ± 4.4°, mLDFA of 86.9° ± 2.5°, MPTA of 85.4° ± 2.4°, arithmetic HKA of -1.4° ± 3.2° and joint line obliquity of 172.5° ± 3.7°. The varus CPAK groups (I/IV/VII) included 435 patients, the neutral groups (II/V/VIII) comprised 630 patients and the valgus groups (III/VI/IX) had 175 patients. Notably, CPAK matrix groups were not distinctly associated with specific coronal extra-articular deformity phenotype (CEDP) groups. Particularly among the most common CPAK matrix groups (I/II/III/IV/V), there was a significant variation in segmental coronal extra-articular deformity patterns. Moreover, when neutral MPTA/mLDFA values were set at 87.0° ± 2.0°, the CPAK matrix groups exhibited even greater variability in coronal extra-articular deformities.

CONCLUSION

The CPAK matrix groups do not exhibit a direct correlation with a specific extra-articular deformity pattern (CEDP), thus rendering them unsuitable for determining segmental coronal extra-articular knee deformities.

LEVEL OF EVIDENCE

Level III, retrospective diagnostic study.

Editorial Commentary: Locking Plate Removal Is Safe and May Improve Function 1 Year After Medial Opening Wedge High Tibial Osteotomy

The development of angular stable locking late fixation in realignment osteotomy has resulted in the ability to be more aggressive with weight bearing and rehabilitation after high tibial osteotomy. One of the downsides of some of these plate fixators is the degree of soft-tissue irritation and discomfort that can be experienced by many patients, resulting in the need for hardware removal. Studies have shown greater than 50% of patients requiring hardware removal with no resulting loss of correction, although there may be cultural reasons for the higher number, not solely attributable to the symptom profile. It is encouraging to see that after 1 year postoperatively, hardware removal after high tibial osteotomy not only is safe but also results in a clinically important improvement in pain and function, with progressive bone healing out to 2 years.

Deformity in valgus knee malalignment is not only in the femur but also in tibia or both, based on demographic and morphological analysis before and after knee osteotomies

PURPOSE

This study aims to identify the demographic and morphological features of valgus knee deformity with unilateral osteoarthritic knee in the coronal plane. A secondary aim was to identify the distinct phenotypes of valgus knees in Hirschmann's phenotype and the coronal plane alignment of the knee (CPAK) classifications before and after a knee osteotomy (KO).

METHODS

A total of 107 patients (57 female and 50 male) with a mean age of 42.4 ± 17.2 years, who underwent varisation osteotomy for symptomatic unilateral knee osteoarthritis (OA) and constitutional valgus deformity, were enrolled in the study, and the mean follow-up period was 29.1 ± 7.3 months. The included cases comprised 60 cases of distal femoral osteotomy, 10 cases of double-level osteotomy and 33 cases of high tibial osteotomy. All patients underwent preoperative and postoperative clinical, functional and radiological evaluations, analysed by analysis of variance tests.

RESULTS

An analysis of the location of the valgus deformities demonstrated that 56 cases (52.3%) were femoral based, 18 cases (16.8%) were both femoral and tibial based and 33 cases (30.9%) were tibial based. Twelve preosteotomy cases (11.2%) and 38 postosteotomy cases (35.5%) matched the most common eight Hirschmann's phenotypes, phenotyping the coronal lower limb alignment based on the native alignment in young patients without OA. Four (3.7%) preosteotomy cases and 89 postosteotomy cases (83.1%) matched the most common three CPAK phenotypes (Ⅰ, Ⅱ, Ⅴ) based on constitutional alignment and joint line obliquity in healthy and osteoarthritic knees.

CONCLUSION

In valgus knee malalignment, the location of the deformity is not only solely femoral-based but also solely tibial-based or combined femoral and tibial-based. An individualised osteotomy approach would be recommended to achieve careful preoperative planning that considers the location of the deformity and the resultant joint line. Hirschmann's and CPAK classification would not be relevant when KO is considered.

LEVEL OF EVIDENCE

Level Ⅳ, retrospective case-control study.

The use of injectable orthobiologics for knee osteoarthritis: A European ESSKA-ORBIT consensus. Part 1-Blood-derived products (platelet-rich plasma)

PURPOSE

The aim of this European Society of Sports Traumatology, Knee Surgery and Arthroscopy (ESSKA) consensus is to provide recommendations based on evidence and expert opinion to improve indications, decision-making and administration-related aspects when using blood-derived orthobiologics (for simplicity indicated as PRP-platelet-rich plasma-with PRP being the most common product) for the management of knee osteoarthritis (OA).

METHODS

Leading European expert clinicians and scientists were divided into a steering group, a rating group and a peer review group. The steering group prepared 28 question-statement sets divided into three sections: PRP rationale and indications, PRP preparation and characterisation and PRP protocol. The quality of the statements received grades of recommendation ranging from A (high-level scientific support) to B (scientific presumption), C (low-level scientific support) or D (expert opinion). The question-statement sets were then evaluated by the rating group, and the statements scored from 1 to 9 based on their degree of agreement with the statements produced by the steering group. Once a general consensus was reached between the steering and rating groups, the document was submitted to the peer review group who evaluated the geographic adaptability and approved the document. A final combined meeting of all the members of the consensus was held to produce the official document.

RESULTS

The literature review on the use of blood-derived products for knee OA revealed that 9 of 28 questions/statements had the support of high-level scientific literature, while the other 19 were supported by a medium-low scientific quality. Three of the 28 recommendations were grade A recommendations: (1) There is enough preclinical and clinical evidence to support the use of PRP in knee OA. This recommendation was considered appropriate with a strong agreement (mean: 8). (2) Clinical evidence has shown the effectiveness of PRP in patients for mild to moderate degrees of knee OA (KL ≤ 3). This recommendation was considered appropriate with a strong agreement (mean: 8.1). (3) PRP injections have been shown to provide a longer effect in comparison to the short-term effect of CS injections. They also seem to provide a safer use profile with less potential related complications. This recommendation was considered appropriate with a very strong agreement (mean: 8.7). Six statements were grade B recommendations, 7 were grade C and 12 were grade D. The mean rating score was 8.2 ± 0.3.

CONCLUSIONS

The consensus group reached a high level of agreement on all the questions/statements despite the lack of clear evidence for some questions. According to the results from this consensus group, given the large body of existing literature and expert opinions, PRP was regarded as a valid treatment option for knee OA and as a possible first-line injectable treatment option for nonoperative management of knee OA, mainly for KL grades 1-3.

LEVEL OF EVIDENCE

Level II.

Valgus malalignment causes increased forces on a medial collateral ligament reconstruction under dynamic valgus loading: A biomechanical study

PURPOSE

To investigate the forces on a medial collateral ligament (MCL) reconstruction (MCLR) relative to the valgus alignment of the knee.

METHODS

Eight fresh-frozen human cadaveric knees were subjected to dynamic valgus loading at 400 N using a custom-made kinematics rig. After resection of the superficial medial collateral ligament, a single-bundle MCLR with a hamstring tendon autograft was performed. A medial opening wedge distal femoral osteotomy was performed and fixed with an external fixator to gradually adjust the alignment in 5° increments from 0° to 10° valgus. For each degree of valgus deformity, the resulting forces acting on the MCLR were measured through a force sensor and captured in 15° increments from 0° to 60° of knee flexion.

RESULTS

Irrespective of the degree of knee flexion, increasing valgus malalignment resulted in significantly increased forces acting on the MCLR compared to neutral alignment (p < 0.05). Dynamic loading at 5° valgus resulted in increased forces on the MCLR at all flexion angles ranging between 16.2 N and 18.5 N (p < 0.05 from 0° to 30°; p < 0.01 from 45° to 60°). A 10° valgus malalignment further increased the forces on the MCLR at all flexion angles ranging between 29.4 N and 40.0 N (p < 0.01 from 0° to 45°, p < 0.05 at 60°).

CONCLUSION

Valgus malalignment of the knee caused increased forces acting on the reconstructed MCL. In cases of chronic medial instabilities accompanied by a valgus deformity ≥ 5°, a realigning osteotomy should be considered concomitantly to the MCLR to protect the graft and potentially reduce graft failures.

LEVEL OF EVIDENCE

Level III.

Fully automated assessment of the knee alignment on long leg radiographs following corrective knee osteotomies in patients with valgus or varus deformities

INTRODUCTION

The assessment of the knee alignment on long leg radiographs (LLR) postoperative to corrective knee osteotomies (CKOs) is highly dependent on the reader's expertise. Artificial Intelligence (AI) algorithms may help automate and standardise this process. The study aimed to analyse the reliability of an AI-algorithm for the evaluation of LLRs following CKOs.

MATERIALS AND METHODS

In this study, we analysed a validation cohort of 110 postoperative LLRs from 102 patients. All patients underwent CKO, including distal femoral (DFO), high tibial (HTO) and bilevel osteotomies. The agreement between manual measurements and the AI-algorithm was assessed for the mechanical axis deviation (MAD), hip knee ankle angle (HKA), anatomical-mechanical-axis-angle (AMA), joint line convergence angle (JLCA), mechanical lateral proximal femur angle (mLPFA), mechanical lateral distal femoral angle (mLDFA), mechanical medial proximal tibia angle (mMPTA) and mechanical lateral distal tibia angle (mLDTA), using the intra-class-correlation (ICC) coefficient between the readers, each reader and the AI and the mean of the manual reads and the AI-algorithm and Bland-Altman Plots between the manual reads and the AI software for the MAD, HKA, mLDFA and mMPTA.

RESULTS

In the validation cohort, the AI software showed excellent agreement with the manual reads (ICC: 0.81-0.99). The agreement between the readers (Inter-rater) showed excellent correlations (ICC: 0.95-0. The mean difference in the DFO group for the MAD, HKA, mLDFA and mMPTA were 0.50 mm, - 0.12°, 0.55° and 0.15°. In the HTO group the mean difference for the MAD, HKA, mLDFA and mMPTA were 0.36 mm, - 0.17°, 0.57° and 0.08°, respectively. Reliable outputs were generated in 95.4% of the validation cohort.

CONCLUSION

 he application of AI-algorithms for the assessment of lower limb alignment on LLRs following CKOs shows reliable and accurate results.

LEVEL OF EVIDENCE

Diagnostic Level III.

Obesity does not impact complications and conversion to total knee arthroplasty after high tibial osteotomy: A systematic review

PURPOSE

The purpose of this systematic review is to consolidate outcomes of obese patients undergoing high tibial osteotomy and to investigate the effect of obesity on postoperative outcomes, including symptomatic relief and time to conversion to arthroplasty.

METHODS

Medline, Embase and Cochrane Library were searched from database inception up to April 2023 according to PRISMA guidelines by two reviewers. Search terms including 'obesity', 'BMI', 'osteotomy' and 'high tibial osteotomy (HTO)' were included to identify all relevant articles. Only studies that explicitly reported outcomes for obese patients were included. Disagreements in study inclusion or quality assessment were resolved by a senior third reviewer. Metrics compared include time to arthroplasty, preoperative and postoperative mechanical tibiofemoral angle (mTFA), patient-reported satisfaction scores and postoperative complications.

RESULTS

Nine studies comparing 973 patients were included. The mean age was 52.7 ± 4.2 years old and 38.4% were male. Six studies performed the medial opening-wedge HTO, and three utilized the medial wedge closing technique. Most studies indicated significant improvement following surgical intervention with satisfactory outcomes in obese and nonobese patients. In addition, differences in complication rates were minimal between obese and nonobese patients (n.s.), while functional scores did not vary significantly. Conversion to total knee arthroplasty was not found to increase in obese patients (n.s.).

CONCLUSION

Obesity does not appear to carry a greater complication risk or worse outcomes following high tibial osteotomies, and surgeons should consider HTO a viable option for young obese patients with symptomatic unicompartmental chondral wear with coronal limb malalignment.

LEVEL OF EVIDENCE

Level IV.

A systematic approach to managing complications after proximal tibial osteotomies of the knee

Proximal tibial osteotomy (PTO) is an effective procedure for active and young adult patients with symptomatic unicompartmental osteoarthritis and malalignment. They were considered technically demanding and prone to various complications related to the surgical technique, biomechanical or biological origin. Among the most important are hinge fractures and delayed or non-healing, neurovascular complications, loss of correction, implant-related problems, patellofemoral complaints, biological complications and changes in limb length. Being aware of these problems can help minimizing their prevalence and improve the results of the procedure.The aim of this narrative review is to discuss the potential complications that may occur during and after proximal tibial osteotomies, their origin and ways to prevent them.

Maintaining Posterior Tibial Slope and Patellar Height During Medial Opening Wedge High Tibial Osteotomy

BACKGROUND

Increased posterior tibial slope (PTS) and decreased patellar height (PH) after medial opening wedge high tibial osteotomy (MOWHTO) have been repeatedly reported in the literature. However, this has been disputed in more recent biomechanical studies.

HYPOTHESIS

No change in PTS or PH would result after MOWHTO with the freehand technique, regardless of the degree of the coronal plane correction.

STUDY DESIGN

Case series.

METHODS

A total of 62 patients who underwent MOWHTO between 2018 and 2020 were included. Surgery was performed using a dedicated step-by-step protocol to reduce the risk of unintentional slope changes. All patients were evaluated preoperatively and at a 2-year follow-up with the Knee injury and Osteoarthritis Outcome Score and the University of California, Los Angeles physical activity scale. Pre- and postoperative radiographic lower limb alignment parameters-including hip-knee-ankle angle (HKA), medial proximal tibial angle (MPTA), mechanical lateral distal femoral angle, proximal posterior tibial angle (PPTA), joint line convergence angle, and joint line obliquity-were measured on full-length lower limb radiographs. PH measurements assessed on lateral and anteroposterior knee radiographs included the Caton-Deschamps, Insall-Salvati, and Schröter indices.

RESULTS

A significant change was observed in the coronal plane alignment, with an increase in the MPTA from 84.38° to 90.39° (P < .001) and a consequent increase in the HKA from 172.19° to 180.15° (P < .001). No significant changes were observed in the PTS, as evidenced by a postoperative PPTA of 80.6° versus a preoperative value of 80.4° (P = .2). No significant changes were detected in the mean PH on all 3 indices used-pre- versus postoperative Caton-Deschamps, Insall-Salvati, and Schröter indices measured 0.95 versus 0.93 (P = .2), 1.03 versus 1.03 (P = .5), and 1.56 versus 1.54 (P = .3), respectively.

CONCLUSION

In this study, MOWHTO did not result in significant changes in the PTS or PH when accurate preoperative planning and precise intraoperative freehand technique were adopted..

Artificial intelligence-based analyses of varus leg alignment and after high tibial osteotomy show high accuracy and reproducibility

PURPOSE

The aim of this study was to investigate the performance of an artificial intelligence (AI)-based software for fully automated analysis of leg alignment pre- and postoperatively after high tibial osteotomy (HTO) on long-leg radiographs (LLRs).

METHODS

Long-leg radiographs of 95 patients with varus malalignment that underwent medial open-wedge HTO were analyzed pre- and postoperatively. Three investigators and an AI software using deep learning algorithms (LAMA™, ImageBiopsy Lab, Vienna, Austria) evaluated the hip-knee-ankle angle (HKA), mechanical axis deviation (MAD), joint line convergence angle (JLCA), medial proximal tibial angle (MPTA), and mechanical lateral distal femoral angle (mLDFA). All measurements were performed twice and the performance of the AI software was compared with individual human readers using a Bayesian mixed model. In addition, the inter-observer intraclass correlation coefficient (ICC) for inter-observer reliability was evaluated by comparing measurements from manual readers. The intra-reader variability for manual measurements and the AI-based software was evaluated using the intra-observer ICC.

RESULTS

Initial varus malalignment was corrected to slight valgus alignment after HTO. Measured by the AI algorithm and manually HKA (5.36° ± 3.03° and 5.47° ± 2.90° to - 0.70 ± 2.34 and - 0.54 ± 2.31), MAD (19.38 mm ± 11.39 mm and 20.17 mm ± 10.99 mm to - 2.68 ± 8.75 and - 2.10 ± 8.61) and MPTA (86.29° ± 2.42° and 86.08° ± 2.34° to 91.6 ± 3.0 and 91.81 ± 2.54) changed significantly from pre- to postoperative, while JLCA and mLDFA were not altered. The fully automated AI-based analyses showed no significant differences for all measurements compared with manual reads neither in native preoperative radiographs nor postoperatively after HTO. Mean absolute differences between the AI-based software and mean manual observer measurements were 0.5° or less for all measurements. Inter-observer ICCs for manual measurements were good to excellent for all measurements, except for JLCA, which showed moderate inter-observer ICCs. Intra-observer ICCs for manual measurements were excellent for all measurements, except for JLCA and for MPTA postoperatively. For the AI-aided analyses, repeated measurements showed entirely consistent results for all measurements with an intra-observer ICC of 1.0.

CONCLUSIONS

The AI-based software can provide fully automated analyses of native long-leg radiographs in patients with varus malalignment and after HTO with great accuracy and reproducibility and could support clinical workflows.

LEVEL OF EVIDENCE

Diagnostic study, Level III.

A significant rate of tibial overcorrection with an increased JLO occurred after isolated high tibial osteotomy without considering international consensus

PURPOSE

The recent ESSKA consensus recommendations defined indications and outlined parameters for osteotomies around a degenerative varus knee. The consensus collated these guidelines based on the published literature available to answer commonly asked questions including the importance of identifying the site and degree of the lower limb deformity. In the consensus, the authors suggest that a knee joint line obliquity (JLO) greater than 5° or a planned medial proximal tibial angle (MPTA) > 94° preferentially indicates a double level osteotomy (DLO) compared to an isolated opening wedge high tibial osteotomy (OWHTO). This study aimed to analyze the corrections performed on a cohort of isolated opening wedge high tibial osteotomies (OWHTOs) prior to the recent ESSKA recommendations, with a focus on the impact of knee joint line obliquity (JLO) and medial proximal tibial angle (MPTA) on the choice of osteotomy procedure.

METHODS

This monocentric, retrospective study included 129 patients undergoing medial OWHTO for symptomatic isolated medial knee osteoarthritis (Ahlbäck grade I or II) and a global varus malalignment (hip-knee-ankle angle ≤ 177°). An automated software trained to automatically detect lower limb deformity was implemented using patients preoperative long leg alignment X-rays to identify suitability for an isolated HTO in knee varus deformity. Based on the ESSKA recommendations, the site of the osteotomy was identified as well as the degree of correction required. The ESSKA consensus considers avoiding an isolated high tibial osteotomy if the planned resultant knee joint line orientation exceeds 5 ̊ or MPTA exceeds 94°. A preoperative abnormal MPTA was defined by a value lower than 85° and a preoperative abnormal LDFA by a value greater than 90°. The cases of DLO or DFO suggested by the software and the number of extra-tibial anomalies were collected. Multiple linear regression models were developed to establish a relationship between preoperative values and the risk of being outside of ESSKA recommendations postoperatively.

RESULTS

Based on ESSKA recommendations and on threshold values considered abnormal, the software suggested a DLO in 17.8% (n = 23/129) of cases, a distal femoral osteotomy in 27.9% (n = 36/129) of cases and advised against an osteotomy procedure in 24% (n = 31/129) of cases. The software detected a femoral anomaly in 34.9% (n = 45/129) of cases and an JLCA > 6° in 9.3% (n = 12/129). Postoperatively, the MPTA exceeds 94° in 41.1% (n = 53/129) and the JLO exceeds 5° in 29.4% (n = 38/129). On multivariate analysis, a high preoperative MPTA was associated with higher risk of postoperative MPTA > 94° (R2 = 0.36; p < 0.001). Similarly, the probability of the software advising a DLO or DFO was associated with the presence of an "normal" preoperative MPTA (R2 = 0.42; p < 0.001) or an abnormal preoperative LDFA (R2 = 0.48; p < 0.001) or a planned JLO > 5° (R2 = 0.27; p < 0.001).

CONCLUSIONS

Analysis of patients who underwent an isolated OWHTO prior to the ESSKA guidelines, demonstrated a significant rate of post-operative tibial overcorrection and a resultant increased JLO. Pre-operative planning that considers the ESSKA guidelines, allows for better identification of those patients requiring a DFO or DLO and avoidance of resultant post-operative deformities.

LEVEL OF EVIDENCE

IV, case-series.

Assessment of return to sport and functional outcomes following distal femoral, double level and high tibial osteotomies for active patients with symptomatic varus malalignment

PURPOSE

This study indicated the outcomes of three surgical techniques for the treatment of symptomatic unicompartmental knee osteoarthritis (UKOA) with varus malalignment in younger, active patients: distal femoral osteotomy (DFO), double-level osteotomy (DLO) and high tibial osteotomy (HTO). The outcomes measured included the return to sport, sport activity and functional scores.

METHODS

A total of 103 patients (19 DFO, 43 DLO, 41 HTO) were enrolled in the study and were divided into three groups based on their oriented deformity, each undergoing one of the three surgical techniques. All patients underwent pre- and post-operative evaluations including X-rays, physical exams and functional assessments.

RESULTS

All three surgical techniques were effective in treating UKOA with constitutional malalignment. The average time to return to sport was similar among the three groups (DFO: 6.4 ± 0.3 [5.8-7] months, DLO: 4.9 ± 0.2 [4.5-5.3] months, HTO: 5.6 ± 0.2 [5.2-6] months). The sport activity and functional scores improved significantly for all three groups, with no significant differences observed among the groups.

CONCLUSION

Various knee osteotomy procedures, DFO, DLO, and HTO, result in high RTS rates and quick RTS times with satisfactory functional scores. Despite pre- to post-operative improvements in sport activities following DFO and DLO, pre-symptom levels were not reached following all evaluated procedures.

LEVEL OF EVIDENCE

Retrospective case-control study, Level III.

The position of the lateral tibial spine and the implications for high tibial osteotomy planning

The lateral tibial spine (LTS) is frequently proposed as a correction target in high tibial osteotomy (HTO), although little is known about its exact radiographic position. This study primarily aims to define the position and variance of the LTS. Secondly, this study wants to investigate the relevance of the LTS position on the mechanical tibiofemoral angle (mTFA°) while planning and postoperatively landing the weight-bearing line (WBL) on this landmark. The LTS position was studied on preoperative full-leg standing radiographs (FLSR) and computed tomography (CT) scans in 70 cases. 3D models of the tibia were created in Mimics 23.0 and measurements were conducted in 3-matic 15.0 (Materialise, Leuven®). Next, 100 HTO cases were retrospectively planned with the WBL through the LTS according to Dugdale's method on FLSR. Finally, 55 postoperative FLSR which had the WBL on the LTS (±2%) were assessed for mTFA° outcome. Statistics were conducted in GraphPad 8.0. The LTS was located at 58.3%±1.9 [55-63%] in 2D and 57.3%±2.2 [53-63%] in 3D showing a high correlation (r=0.77 [0.65 to 0.85]). The planned mTFA on the LTS was 181.8°±0.3 (181.3°-182.5°). On postoperative FLSR, the mTFA was 182.2°±0.6 (180.9°-183.1°). The lateral tibial spine is located at 57-58% on the tibial plateau with a 10% maximal variation range. Good agreement was found between 2D and 3D imaging modalities while evaluating its position in the coronal plane. When aiming the WBL through the LTS during valgus-producing HTO, a consistent realignment of 181-183° mTFA can be expected when performing accurate surgery.