Equipment

Advances in instrumentation for unicompartmental knee arthroplasty (UKA) have increased the surgeon’s ability to implant the components in proper alignment and should theoretically increase the longevity of the arthroplasty. Instrumentation is crucial for proper alignment and orientation with some types of UKA systems, such as the Oxford Phase III prosthetic.^{[30, 31, 32]} Other prosthetic systems, such as the Repicci II, rely more on anatomic landmarks to ensure proper component placement.

Patient Preparation

The patient is placed in a supine position, with the draped leg set on a thigh support or in a legholder. In positioning the patient, it is necessary to ensure that the knee is free to flex to at least 110-120°.

A sandbag or other bump is affixed to the table to help maintain flexion of the knee. A strap placed around the thigh and leg may serve the same function. The leg is draped free, and it is helpful to place a mark or ball of tape over the anterior superior iliac spine or the femoral head.

Monitoring & Follow-up

Mobilization of the knee and patient can start on postoperative day 1. Recovery of knee function is usually rapid, with considerably less pain than that which occurs with a total knee arthroplasty (TKA). Early mobilization is encouraged, and passive assistance by the physical therapist is advised. The patient can frequently be discharged after 2-3 days. In some centers, the procedure is now performed in day care.

Mechanical prophylaxis against deep vein thrombosis is recommended for the duration of the hospitalization. Postdischarge prophylaxis is at the discretion of the surgeon.

Technique

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Media Gallery

Unicompartmental knee arthroplasty. The minimally invasive technique with a paramedial skin incision.
Extension of the minimally invasive skin incision for a total knee arthroplasty.
The mobile-bearing unicompartmental prosthesis.
Unicompartmental knee arthroplasty. When a mobile-bearing prosthesis is used, the bearing can become dislocated.
Revision to a total knee arthroplasty; view after removal of the unicompartmental prosthesis.
Revision to a total knee arthroplasty. The earlier femoral-condylar bone cut/milling of the unicompartmental knee arthroplasty is usually less or the same as that for total knee replacement distal femoral (medial and lateral condyle) resection.
Revision to a total knee arthroplasty. The medial or lateral proximal tibial plateau resection of the unicompartmental knee arthroplasty is usually at the same level as the proximal tibial plateau resection for total knee arthroplasty.
Unicompartmental knee arthroplasty. A tibial plateau fracture may occur when too much stress is applied with cementation of the tibial component or after adequate trauma. The vertical tibial cut may act as a stress line.

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Author

Nanne P Kort, MD, PhD Consulting Staff, Department of Orthopedic Surgery, Zuyderland Medical Center, Sittard, The Netherlands

Nanne P Kort, MD, PhD is a member of the following medical societies: American Academy of Orthopaedic Surgeons, European Society for Sports Traumatology, Knee Surgery and Arthroscopy

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: ZImmer-Biomet / BodyCad<br/>Serve(d) as a speaker or a member of a speakers bureau for: Depuy.

Coauthor(s)

Marcus Romanowski, MD Chief, Department of Orthopedic Surgery, Kenmore Mercy Hospital; Director, Knee and Hip Center, Kenmore Mercy Hospital; Partner, Joint Reconstruction Orthopedics

Marcus Romanowski, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons, Arthritis Foundation

Disclosure: Nothing to disclose.

Jos Van Raay, PhD Associate Chair, Residency Director, Department of Orthopedic Surgery, Martini Hospital Groningen, Netherlands

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Thomas M DeBerardino, MD Orthopedic Surgeon, UT Health San Antonnio; Professor of Orthopedic Surgery, University of Texas Health Science Center at San Antonio, Joe R and Teresa Lozano Long School of Medicine; Professor of Orthopedic Surgery and Faculty of Sports Medicine Fellowship, Baylor College of Medicine; Consulting Surgeon, Sports Medicine, Arthroscopy and Reconstruction of the Knee, Hip and Shoulder

Thomas M DeBerardino, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons, American Orthopaedic Association, American Orthopaedic Society for Sports Medicine, Arthroscopy Association of North America, Herodicus Society, International Society of Arthroscopy, Knee Surgery and Orthopaedic Sports Medicine

Disclosure: Serve(d) as a director, officer, partner, employee, advisor, consultant or trustee for: Arthrex, Inc.; MTF; Aesculap; Conmed; JRF<br/>Received research grant from: Arthrex, Inc.; MTF.

Additional Contributors

Howard A Chansky, MD Associate Professor, Department of Orthopedics and Sports Medicine, University of Washington Medical Center

Howard A Chansky, MD is a member of the following medical societies: American Academy of Orthopaedic Surgeons

Disclosure: Nothing to disclose.