Valgus bracing in symptomatic varus malalignment for testing the expectable "unloading effect" following valgus high tibial osteotomy

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.

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.

[Treatment of unicompartmental osteoarthritis of the knee]

Osteoarthritis of the knee is one of the most important degenerative joint diseases in the clinical routine. The treatment of knee osteoarthritis is not only based on the stage, symptoms and duration of the joint disease, but also depends on the existing arthrosis pattern. In the case of unicompartmental arthrosis, damage typical for osteoarthritis is limited to just one joint compartment. Both the conservative and the surgical treatment of unicompartmental osteoarthritis of the knee have to respect the individual characteristics of the respective forms of osteoarthritis. In the context of this manuscript, the genesis, the diagnostics and the guideline-based stage-adapted conservative and operative treatment of unicompartmental osteoarthritis of the knee are addressed.

Clinical Effect of Isolated Lateral Closing Wedge Distal Femoral Osteotomy Compared to Medial Opening Wedge High Tibial Osteotomy for the Correction of Varus Malalignment: A Propensity Score-Matched Analysis

BACKGROUND

Recent evidence questions the role of medial opening wedge high tibial osteotomy (mowHTO) in the correction of femoral-based varus malalignment because of the potential creation of an oblique knee joint line. However, the clinical effectiveness of alternatively performing an isolated lateral closing wedge distal femoral osteotomy (lcwDFO), in which the mechanical unloading effect in knee flexion may be limited, is yet to be confirmed.

PURPOSE/HYPOTHESIS

The purpose of this article was to compare clinical outcomes between patients undergoing varus correction via isolated lcwDFO or mowHTO, performed according to the location of the deformity, in a cohort matched for confounding variables. It was hypothesized that results from undergoing isolated lcwDFO for symptomatic varus malalignment would not significantly differ from the results after mowHTO.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

Consecutive patients who underwent isolated mowHTO or lcwDFO according to a tibial- or femoral-based symptomatic varus deformity between January 2010 and October 2019 were enrolled. Confounding factors, including age at surgery, sex, body mass index, preoperative femorotibial axis, and postoperative follow-up, were matched using propensity score matching. The International Knee Documentation Committee (IKDC) Subjective Knee Form, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lysholm score, Tegner Activity Scale, and visual analog scale (VAS) for pain were collected preoperatively and at a minimum of 24 months postoperatively.

RESULTS

Of 535 knees assessed for eligibility, 50 knees (n = 50 patients, n = 25 per group) were selected by propensity score matching. Compared with preoperatively, both the mowHTO group (IKDC, 55.1 ± 16.5 vs 71.3 ± 14.7, P = .002; WOMAC, 22.0 ± 18.0 vs 9.6 ± 10.8, P < .001; Lysholm, 55.2 ± 23.1 vs 80.7 ± 16, P < .001; VAS, 4.1 ± 2.4 vs 1.6 ± 1.8, P < .001) and the lcwDFO group (IKDC, 49.4 ± 14.6 vs 66 ± 20.1, P = .003; WOMAC, 25.2 ± 17.0 vs 12.9 ± 17.6, P = .003; Lysholm, 46.5 ± 15.6 vs 65.4 ± 28.7, P = .011; VAS, 4.5 ± 2.2 vs 2.6 ± 2.5, P = .001) had significantly improved at follow-up (80 ± 20 vs 81 ± 43 months). There were no significant differences between the groups at baseline, at final follow-up, or in the amount of clinical improvement in any of the outcome parameters (P > .05; respectively).

CONCLUSION

Performing both mowHTO or lcwDFO yields significant improvement in clinical outcomes if performed at the location of the deformity of varus malalignment. These findings confirm the clinical effectiveness of performing an isolated lcwDFO in femoral-based varus malalignment, which is comparable with that of mowHTO in the correction of varus malalignment.

Biplanar high tibial osteotomy for the combined correction of varus and posterior tibial slope malalignment

Varus malalignment combined with an increased posterior tibial slope (PTS) in the ACL deficient knee is a frequent pathology; yet, treatment for this condition remains challenging. The presented biplanar osteotomy technique allows to simultaneously address both components of malalignment in a single step. A detailed preoperative planning is best achieved by means of a digital planning software and constant intraoperative imaging is performed to verify the correction angle. A bony wedge is resected along with the extension osteotomy according to the preoperative planning and the medial-opening tibial osteotomy site is filled with bone allograft. Two bicortical lag screws are placed in anterior-posterior direction to secure the extension osteotomy, whereas a plate fixation is used for the medial-open osteotomy.

Are All Unloader Braces Created Equal? Recommendations for Evidence-Based Implementation of Unloader Braces for Patients with Unicompartmental Knee OA

Unicompartmental knee osteoarthritis (UKOA) is a complex issue that is estimated to affect roughly 28% of patients with knee OA, and can result in severe cartilage degeneration, meniscus deficiency, and concomitant varus or valgus malalignment. This malalignment results in abnormally high joint reaction forces in the affected compartment, which can elicit pain, cause dysfunction, and exacerbate joint degradation. For more than two decades, the use of knee unloader braces has been advocated as a cost-effective option for symptomatic management of UKOA.During bipedal ambulation with a normal lower extremity mechanical axis, ground reaction forces create a knee adduction moment (KAM) such that the medial compartment of the knee experiences approximately 60% of joint loading and the lateral compartment experiences approximately 40% of joint loading. UKOA disrupts the mechanical axis, altering KAM and joint loading and causing pain, dysfunction, and disease progression. In theory, knee unloader braces were designed to mitigate the symptoms of UKOA by normalizing KAM via shifts in the lever arms about the knee. However, studies vary, and suggest that push-mechanism knee unloaders do not consistently provide significant biomechanical benefits for medial or lateral UKOA. Current evidence suggests that pull-mechanism unloaders may be more effective, though contrasting data have also been reported, such that further validation is necessary. The purpose of our study was to synthesize current best evidence for use of knee unloader braces for management of UKOA to suggest evidence-based best practices as well as gaps in knowledge to target for future studies. Unloader bracing for patients with UKOA appears to be a cost-effective treatment option for patients with medial UKOA who have insurance coverage. Pull-mechanism unloader bracing should be considered in conjunction with other nonoperative management therapies for those who are willing to adhere to consistent brace use for weight-bearing activities.

High Tibial Osteotomy for Varus Deformity of the Knee

High tibial osteotomy is a powerful technique to treat symptomatic varus deformity of the knee and is successful when properly indicated and performed. Indications include varus deformity with medial compartment osteoarthritis, cartilage or meniscus pathology. Several techniques exist to correct symptomatic varus malalignment along with concomitant procedures to restore cartilage or meniscus injuries. Evidence supporting high tibial osteotomy for symptomatic medial compartment pathology exists, which provides a durable solution for joint preservation. This review will discuss the indications, techniques, and outcomes for high tibial osteotomies used in the treatment of symptomatic varus deformity of the knee.

Medial compartment osteoarthritis of the knee: a review of surgical options

Osteoarthritis of the medial compartment, where the lateral compartment and patella-femoral joint are relatively spared, is a common orthopaedic presentation.

Most frequently, the treatment of choice would be a total knee replacement, which involves removing healthy joint surfaces in such patients.

Arthroscopic debridement in the osteoarthritic knee has fallen out of favour due to poor clinical results.

A trend has developed towards less invasive surgery with uni-compartmental knee replacement (UKR) and high tibial osteotomy (HTO) gaining increasing popularity.

Surgeons differ in their relative indications and contraindications to performing these procedures.

Total knee replacement (TKR) continues to have the lowest overall revision rate of the available options.

Growing evidence demonstrates more favourable patient-reported outcome measures in UKR and HTO patients, compared to TKR.

Knee joint distraction (KJD) has been demonstrated as an alternative method of treatment in such patients.

Cite this article: EFORT Open Rev 2021;6:113-117. DOI: 10.1302/2058-5241.6.200102

High tibial osteotomy increases patellofemoral pressure if adverted proximal, while open-wedge HTO with distal biplanar osteotomy discharges the patellofemoral joint: different open-wedge high tibial osteotomies compared to an extra-articular unloading device

PURPOSE

Valgus high tibial osteotomy (HTO) and a recently introduced extra-articular absorber have been shown to efficiently unload the medial compartment of the knee. However, only little is known about the influence of these treatment modalities on biomechanics of the patellofemoral joint. The purpose of this study was to investigate and compare the impact of different HTO techniques and implantation of an extra-articular absorber on patellofemoral contact forces.

METHODS

Fourteen fresh frozen cadaveric knees were tested in a specially designed knee simulator that allowed simulation of isokinetic flexion-extension motions under physiological loading. Mean contact pressure (ACP) and peak contact pressure (PCP) of the patellofemoral joint was measured continuously between 0° and 120° of knee flexion using a pressure sensitive film in the following conditions: native, after biplanar medial open-wedge HTO with 5° and 10° correction angle performing an ascending frontal osteotomy of the tibial tuberosity, and after implantation of an extra-articular absorber system (KineSpring®). Including a second testing cycle with a biplanar medial open-wedge HTO with 5° and 10° correction angle performing descending frontal osteotomy of the tibial tuberosity. Values after each procedure were compared to the corresponding values of the native knee.

RESULTS

Biplanar proximal osteotomy leaded to a significant increase of retropatellar compartment area contact pressure compared to the first untreated test cycle (Δ 0.04 ± 0.01 MPa, p = 0.04). Similar results were observed measuring peak contact pressure (Δ 1.41 ± 0.15 MPa, p = 0.03). With greater correction angle 5°, respectively, 10° peak and contact pressure increased accordingly. In contrast, the biplanar distal osteotomy group showed significant decrease of pressure values (p = 0.004). The extracapsular, extra-articular absorber had no significant influence on pressure levels in the patellofemoral joint.

CONCLUSION

HTO with a proximal biplanar osteotomy of the tuberositas tibia significantly increased patellofemoral pressure conditions depending on the correction angle. In contrast a distally directed biplanar osteotomy diminished these effects while implantation of an extracapsular, extra-articular absorber had no influence on the patellofemoral compartment at all. Consequently, patients with varus alignment with additional retropatellar chondropathia should be treated with a distally adverted osteotomy to avoid further undesirable pressure elevation in the patellofemoral joint.

Unloader knee brace increases medial compartment joint space during gait in knee osteoarthritis patients

PURPOSE

The purpose of the present study was to investigate the effect of the unloader brace on medial compartment dynamic joint space (DJS) during gait, while simultaneously recording ground reaction force (GRF) in varus knee osteoarthritis (OA) patients using a highly accurate biplane radiography system which allowed continuous measurement of DJS from heel strike through the midstance phase of gait. The hypothesis was that DJS in the medial compartment would be greater with the unloader brace than without the brace during gait.

METHODS

After 2 weeks of daily use of the unloader brace, ten varus knee OA patients (age 52 ± 8 years) walked with and without the brace on an instrumented treadmill, while biplane radiographs of the OA knees were acquired at 100 Hz. Medial compartment DJS was determined from heel strike to terminal stance (0-40% of the gait cycle) using a validated volumetric model-based tracking process that matches subject-specific 3D bone models to the biplane radiographs. The GRF during gait was collected at 1000 Hz. Repeated-measures ANOVA was used to explore differences in medial compartment DJS and GRF between the unbraced and braced conditions. A patient-reported subjective questionnaire related to the brace use was collected at the time of the test.

RESULTS

Medial compartment DJS was significantly greater with the unloader brace than without the brace during gait (P = 0.005). The average difference was 0.3 mm (95% confidence interval 0.1-0.4 mm). No significant difference was observed in terms of vertical GRF between the two conditions. The questionnaire showed participants felt reduced pain when wearing the brace.

CONCLUSION

The unloader brace has the significant effect of increasing medial compartment DJS during gait, which supports the underlying premise that the unloader brace reduces pain by increasing medial joint space during dynamic loading activities.

LEVEL OF EVIDENCE

III.

Prophylaxis of medial compartment gonarthrosis in varus knee - current state of knowledge

The progression of gonarthrosis results in reduction of physical activity. One of the factors that increase the risk of osteoarthrosis may be joint overload related to the malalignment of the mechanical axis of the lower extremity. The medial compartment (MC) of the knee is particularly susceptible to overload due to the external knee adduction moment (EKAM). Varus knee malalignment contributes to increased EKAM and thus results in increased MC loading. The purpose of this study is to present methods described in current literature aimed at reducing the disproportion in the distribution of loads on articular surfaces of medial and lateral knee compartments in people with varus knee malalignment. Methods have been divided into non-surgical (gait training, physiotherapy, and orthopedic supplies such as valgus braces, lateral wedge insoles, walking poles) and surgical ones (corrective osteotomy).

[Unloading with insoles, orthotics and braces : Pre-operative leg axis correction or independent treatment?]

BACKGROUND

Knee osteoarthritis (OA) is a leading joint disease. In most of the early stages it does not involve the whole knee joint. Often, symptoms only or mainly concern the medial compartment combined with a slight varus malalignment.

OBJECTIVES

Do valgus braces or laterally wedged insoles influence biomechanics and thus improve pain and function in patients with medial OA? Does the OA grade, severity of malalignment or patient's body weight predict the efficacy of the above-mentioned conservative treatment options?

MATERIALS AND METHODS

The current literature was reviewed in regard to biomechanical changes to joint loading and their correlation to clinical results.

RESULTS

Valgus braces and laterally wedged insoles reduce knee adduction moment, varus malalignment and analgesic consumption. Some authors suggest that mainly an alteration in muscle activity (diminished muscle co-contractions) is responsible for pain relief. Body weight and severity of varus malalignment did not influence treatment results; a significant correlation with OA severity was shown only for laterally wedged insoles. For both devices, compliance problems - especially long-term - should be considered, and conclusive evidence of positive clinical effects cannot be stated.

CONCLUSIONS

Despite positive evidence in the current literature, a recommendation for or against valgus (unloader) braces in medial OA is not possible due to inconclusive results. Laterally wedged insoles are not recommended. Especially the long-term results are doubtful, and are possibly related to lacking compliance.