The Shoulder and Elbow.- Mini-Incision bankart Repair for Shoulder Instability.- Mini-Open Rotator Cuff Repair.- Mini-Incision Fixation of Proximal Humeral Four-Part Fractures.- Minimally Invasive Approach for Shoulder Arthroplasty.- Mini-Incision Medial Collateral Ligament Reconstruction of the Elbow.- Mini-Incision Distal Biceps Tendon Repair.- The Hip.- A Technique for the Anterolateral Approach to MIS Total Hip Replacement.- The Anterior Approach for Total Hip Replacement: Background and Operative Technique.- Posterolateral Minimal Incision for Total Hip Replacement: Technique and Early Results.- Minimally Invasive Total Hip Arthroplasty Using the Two-Incision Approach.- Minimally Invasive Metal-on-Metal Resurfacing Arthroplasty of the Hip.- The Knee: Unicondylar Knee Arthroplasty.- Minimally Invasive Surgery for Unicondylar Knee Arthroplasty: The Bone-Sparing Technique.- Minimally Invasive Surgery for Unicondylar Knee Arthroplasty: The Intramedullary Technique.- Minimally Invasive Surgery for Unicondylar Knee Arthroplasty: The Extramedullary Tensor Technique.- Minimally Invasive Surgery for Unicondylar Knee Arthroplasty: The Extramedullary Technique.- Minimally Invasive Surgery for Arthroplasty with the UniSpacer.- Minimally Invasive Technique for Insertion of a Unicompartmental Knee Arthroplasty.- The Knee: Total Knee Arthroplasty.- Minimal Incision Total Knee Arthroplasty with a Limited Medial Parapatellar Arthrotomy.- Minimally Invasive Total Knee Replacement with the Quadriceps-Sparing Subvastus Approach.- Mini-Midvastus Total Knee Arthroplasty.- Minimally Invasive Lateral Approach to Total Knee Arthroplasty.- Minimally Invasive Total Knee Arthroplasty Using the Quadriceps-Sparing Approach.- Computer Navigation.- Computer-Guided Total Hip Arthroplasty.- Computer-Guided Total Knee Arthroscopy.
"Section III The Knee: Unicondylar Knee Arthroplasty (p. 190-191)
12 Minimally Invasive Surgery for Unicondylar Knee Arthroplasty: The Bone-Sparing Technique
John A. Repicci and Jodi F. Hartman
When considering treatment options for osteoarthritis of the knee, the pathology and progression of the disease must be considered. Past studies examining osteoarthritis of the knee have demonstrated that the disease is slow, progressive, and typically limited to the medial tibiofemoral compartment.1–4 Moreover, the erosion of cartilage in the medial compartment is almost always limited to the anterior half of the medial tibial plateau and the corresponding contact area on the distal portion of the medial femoral condylar.4 Anteromedial osteoarthritis was coined by White et al. to describe this distinct clinicopathological condition.
The ensuing anatomic defect, namely, loss of articular cartilage in the extension gap with no corresponding loss of articular cartilage in the ?exion gap, results in a 6-mm to 8-mm disparity between the extension and ?exion gaps. For this reason, medial osteoarthritis also may be considered an extension gap disease (Figure 12.1). The joint surface asymmetry also accounts for the varus alignment and lateral tibial thrust commonly associated with medial unicompartmental osteoarthritis.
At this stage in the disease process, the medial meniscus is either partially torn or completely compromised and tension is compromised in the anterior cruciate (ACL) and medial collateral (MCL) ligaments.5 To compensate for the varus deformity, a sclerotic layer of bone, or medial tibial buttress is formed. As varus angulation increases, the medial tibial buttress hypertrophies to resist the increasing varus stresses. Although this may appear to be a rather inef?cient solution, this layer of sclerotic bone allows the medial compartment to withstand joint loading and to support weight, permitting continued ambulation for 10 to 19 years after initiation of the disease.
Eventually, however, patients experience weight-bearing pain as a result of the plastic deformation of bone at the articular surface, instability because of ligamentous laxity, and mechanical symptoms due to meniscal damage.5 The clinical presentation of this early, unicompartmental form of osteoarthritis must be differentiated from that of patients with more advanced forms of the disease. The pain associated with the tricompartmental form of the disease often is so debilitating that activities of daily living are severely restricted, independence is lost, and ambulatory aids, such as crutches, a walker, or wheelchair, are required. For these patients, total knee arthroplasty (TKA) is the most appropriate surgical option to relieve pain and to restore some degree of independence."
