Treatment modalities for patients with varus medial knee osteoarthritis

Abstract

Osteoarthritis (OA) is one of the most common joint disorders in the Western population, which causes pain, stiffness, loss of function and disability. In patients with OA the cartilage, located at the ends of long bones, is damaged. OA is most prevalent in the knee joint. In case of varus malalignment the medial compartment of the knee is most commonly affected. The initial treatment of varus medial knee OA is non-operative, and consists of patient education, weight reduction, physical therapy, use of orthoses, intra-articular steroid injections and if needed pain medication. Orthoses are intended to unload the medial compartment of the knee. Not all patients experience benefit of orthoses and therapeutic effect vary between studies. Therefore the first aim of this thesis was to evaluate the therapeutic effect of orthoses in the treatment of varus medial knee OA. When non-operative treatment fails surgical treatment will mostly be considered. The surgical treatment consists of valgus high tibial osteotomy (HTO), unilateral knee arthroplasty (UKA) or a total knee arthroplasty (TKA). In case of isolated medial knee OA, a HTO or UKA is mostly the preferred intervention. OA is a chronic disease which could progress over years. One of the goals of a HTO is to slow down disease progression and to postpone the need for a TKA as long as possible, by unloading the diseased compartment. Multiple studies comparing different HTO techniques are published with a 1 or 2 year follow-up, however there is a lack of prospective long term results, especially for the relatively new opening-wedge technique. Therefore the second aim of this thesis was to study the long term results of both closing- and opening-wedge HTO. In general, results after TKA and HTO are good. However, a subset of patients has suboptimal improvement in pain, physical functioning, and quality of life and are not satisfied with their postoperative result. The explanation of these suboptimal results is not always completely physical. Psychological factors, such as anxiety and depressive symptoms or preoperative expectations, could be related to these suboptimal results. The ultimate goal of all orthopaedic procedures is patient satisfaction. Identification of modifiable risk factors for dissatisfaction could contribute to optimization of this important outcome. Therefore the final question addressed in this thesis is whether the different psychological factors are related to patient satisfaction after TKA. In Chapter 2 we summarized the literature about the therapeutic effect of orthoses in the treatment of knee OA. In this Cochrane review 13 studies including 1356 patients were included. Overall, quality of evidence found in these studies was moderate or low. The follow-up time varied from 1 – 24 months. No long term follow-up study determining the influence on progression of OA has been performed. We concluded that a valgus knee brace and a laterally wedged insole both have small beneficial effects in terms of improvement of pain, symptoms and functional outcome in patients with varus medial knee OA. No certain difference between both interventions was seen in this Cochrane review. The long term adherence was low for both intervention, especially the knee brace group. Moreover, there might be no difference in therapeutic effect between a laterally wedged insole and a neutral insole. In Chapter 3 we present the results of our biomechanical evaluation of the valgus knee brace and laterally wedged insole. In this study we performed gait analysis of patients with varus medial knee OA treated with one of these two interventions for six months. Gait analysis was performed at baseline and after six weeks of wearing the intervention. In this study we found that wedged insoles only unload the medial compartment at baseline. At baseline a reduction of the peak Knee Adduction Moment (surrogate measure of the medial load) of 3.6% was seen. No biomechanical alteration was seen after 6 weeks of wearing the insole. Valgus brace therapy did not result in any biomechanical alteration at baseline and after 6 weeks. So in this study we could not confirm that the beneficial effects of orthoses can be explained by a certain dynamical alteration, in other words a changed gait pattern. In Chapter 4 the six year results of our RCT comparing closing and opening-wedge HTO are presented. After six year opening-wedge HTO was associated with more complications (37% vs 9%), however closing-wedge HTO was associated with more early conversions to TKA (25% vs 8%). Of the patients who had no conversions to a TKA, no difference in clinical outcome and radiological alignment was seen. We present in Chapter 5 the results of a retrospective assessment of all patients who underwent a HTO in our clinic. We found in this study of 412 patients more adverse events in a closing-wedge group than in an opening-wedge group (28% versus 14%). Hardware was removed in 48% of the closing-wedge HTO’s and 71% of the openingwedge HTO’s. Another major adverse event was iliac crest pain, caused by harvesting the bone for spongiosaplasty (19,7% of the patients in the opening-wedge group). The survival of the opening-wedge group was significantly better than the closing-wedge group, when conversion to a prosthesis was taken as endpoint, however an equal number of patients were in need for a UKA or TKA in both groups. We summarized the literature about the influence of preoperative expectations on patient satisfaction after TKA in Chapter 6. In this systematic review 3 high and 5 low quality studies were included. Although it is a frequently assumed relation, we conclude in this review that there is only limited or conflicting evidence that high expectations lead to more dissatisfaction. However, moderate evidence was found that unfulfilled expectations lead to more dissatisfaction. In Chapter 7 we present the results of our multicenter study, in which we examined the prevalence of two important psychogical symptoms, namely depressive and anxiety symptoms in patients with end-stage OA of the knee. These psychological symptoms were measured with the Hospital Anxiety and Depression Scale, a widely used validated questionnaire. Besides, we determined the influence of these symptoms on the outcome of TKA. We found in this study a high prevalence of anxiety (20.3%) and depressive symptoms (22.7%) in a population with end stage knee OA. After surgery a significant decrease of the prevalence of these symptoms was seen. The prevalence of anxiety symptoms decreased to 14.8% and of depressive symptoms to 11.7%. Preoperative depressive symptoms predicted lower patient reported outcomes after surgery. Patients with preoperative anxiety or depressive symptoms were less satisfied postoperatively. The main topics of this thesis are placed in a broader perspective in Chapter 8. The limitations of this thesis and some recommendations for future research are discussed in this chapter.