Preoperative Evaluation of the Patient for Treatment With a Calipered Kinematically Aligned Total Knee Arthroplasty

Overview

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With calipered kinematic alignment (KA) technique, preoperative management and evaluation of the arthritic knee patient does not vary vastly from the standard evaluation. However, there are some subtle differences that can aid the surgeon in planning and discussing the surgery with patients.
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This chapter introduces how to assess the patient in the office in terms of history, physical exam, and the recommended radiographs. This chapter will also discuss how to counsel patients on the kinematic alignment (KA) technique and answer questions regarding their expectations.

Introduction

Initial evaluation of a patient with knee arthritis should include taking a standard, thorough history of the patient’s symptoms, including previous surgeries and other nonsurgical treatment. As a KA surgeon, one should elicit and document the patient’s recognition of a knee deformity and any worsening of this condition. Given that the tenet of the KA technique is to restore the prearthritic alignment of the patient’s knee, prompting the patient to recognize their alignment will facilitate the discussion with regards to patient expectations postoperatively.

History

Taking a standard history for the presenting knee pain is obviously paramount. Some critical points in the history that are somewhat more relevant for KA total knee arthroplasty (TKA) are highlighted below.

Patient’s recognition of deformity, including recent worsening of deformity: Some patients may have been aware of their “bowlegs” or “knock knees” their entire life, whereas others may not realize they have any deformity whatsoever. They also may have realized a subtle deformity that has been worsening more recently. Once the discussion of surgery starts, specifically on technique, patient’s self-awareness of their deformity can facilitate the information shared to the patient about the KA technique.

Previous trauma (tibial plateau, distal femur fractures) or realignment surgeries (high tibial osteotomy, tibial tubercle osteotomy): can alter the patient’s natural alignment. We will cover techniques and adjustments for some of these deformities in Chapter 14 (Managing Severe Deformities.

Previous contralateral TKA: Any patient who has had previous TKA may have certain preconceived notions about TKA surgery. They could be 100% satisfied with their outcome, completely dissatisfied, or have some level of satisfaction in between these two extremes. Any operative notes, familiarity with the surgeon, or previous radiographs before the TKA can help with understanding what technique was used for component alignment. Understanding what was performed previously and the patient’s subsequent outcome can assist the KA surgeon with their justification of utilization of the KA technique.

All other history such as previous nonsurgical treatments, aggravating and alleviating activities, current level of activity, etc. would be used to decide a patient’s candidacy for TKA, which is no different than current standard recommendations. All the authors support current American Academy of Orthopaedic Surgeons (AAOS) guidelines for management of knee osteoarthritis.

Physical Exam

The physical examination of the knee can be involved and complex, and should be as thorough as possible for any patient being considered for TKA. Some examination findings for particular attention for KA surgeons are featured here.

Gait: Knee deformity can have dramatic effects on gait, some of which are compensatory and others pathologic. Critically observing and recording bilateral deformity and gait abnormalities will allow for comparison once a KA knee has been restored to native alignment.

Standing knee analysis: Visualizing and possibly photographing both knees in a standing posture can again be helpful for understanding the patient’s deformity and for later postoperative comparison.

Patella tracking: Any preoperative maltracking issues need to be documented accurately. Subsequent Chapters 10 and 18 are devoted to minimizing the risk of devoted to avoiding and treating maltracking in the KA TKA; therefore, preoperative pathology will be critical to documenting, correcting, and avoiding postoperative problems with the patella.

Many other physical examination findings are critical for preoperative evaluation, but not any different for any other technique for TKA. Previous incisions, range of movement, laxity, etc. are all taken into consideration and should be documented.

Radiographs

No consensus exists regarding optimal X-rays needed for preoperative evaluation of total knee replacement among knee arthroplasty surgeons, regardless of technique. At a minimum, an anterior-posterior (AP), lateral, and patellofemoral views allow for an initial evaluation. Within each of these subsets, weight-bearing versus non-weight-bearing, flexion angle, and countless other variations are often debated. The simplicity of the KA technique does not absolutely require any specific radiographs for preoperative planning. However, there are radiographic modalities that can possibly aid the KA surgeon with preoperative planning and subsequent postoperative validation.

A full-length, long-leg, weight-bearing AP radiograph of both lower extremities can provide a true measurement of the preoperative deformity, limited to the two-dimensional coronal plane. The contralateral extremity can also be measured and can fall under a number of categories, including normal, arthritic, replaced, and so on. Understanding the presence or absence of deformity in the contralateral knee can aid the surgeon in planning, as well as demonstrate to the patient what “normal” should be in their knee. Measurement of the femoral joint line valgus angle and tibial angle can also help verify intraoperative measurements, as can understanding where the mechanical hip-to-ankle axis falls relative to the native joint ( Figs. 4.1 – 4.4 ).