UNICOMPARTMENTAL KNEE ARTHROPLASTY MINIMALLY INVASIVE TECHNIQUE

Frank R. Ebert, MD Assistant Chief Department of Orthopædics The Union Memorial Hospital Baltimore, Maryland

History Unicompartmental knee arthroplasties have been in use since the early 1970’s. UKA quickly gained popularity, but soon got a bad reputation, especially in the USA.

UKA Failures Improper indications Improper indications Poor surgical technique (no guides) Poor surgical technique (no guides) Inferior prosthetic designs in some cases (e.g. PCA) Inferior prosthetic designs in some cases (e.g. PCA)

UKA Failures cont’d. Improper Indication Improper Indication  Inflammatory Arthritis  Obesity  Severe Deformity (> 10° Varus/>15° Valgus)  Active Young Patient

UKA Failures cont’d. Surgical Technique Surgical Technique  Overcorrection  Undercorrection  Patellar Impingement on Femur  Component Malposition

UKA Failures cont’d. Prosthetic Design Prosthetic Design  6-mm Polyethylene  Cementless Fixation

UKA results Some prostheses like the Marmor, St George Sledge, and the M.G. have proven good long term results

UKA Results Swedish Registry 1975 to 1991 Swedish Registry 1975 to 1991  93% Survivorship over 16 years

UKA Results Swedish Registry Swedish Registry  90% Plus Survivorship – Surgeons doing 15 or more per year.  70% to 80% Survivorship – Surgeons doing less than 15 per year.  Lesson: DO IT RIGHT! (Technique and Patient Selection) (Technique and Patient Selection)

Advantages UKA Less invasive surgery Less invasive surgery Shorter hospital stay Shorter hospital stay Better ROM than TKA Better ROM than TKA More ”normal knee” More ”normal knee” Easier revision Easier revision

”Miniarthrotomy” John A Repicci Buffalo USA

Minimally invasive surgery ”Miniarthrotomy” Early mobilisation Early mobilisation No Transfusion No Transfusion Short hospital stay Short hospital stay Low Morbidity Low Morbidity Quick rehabilitation Quick rehabilitation

Concerns Repicci II Demanding surgical technique Demanding surgical technique No guides - ”free hand surgery” No guides - ”free hand surgery” Thin tibial component (6 - 7 mm) Thin tibial component (6 - 7 mm) Limited Sizes Limited Sizes Long term results? Long term results?

Why Miller - Galante uni? Proven good / excellent long term Proven good / excellent long term clinical results clinical results Excellent results (Nilsson & Dahlen, Hyldahl et. al.) Excellent results (Nilsson & Dahlen, Hyldahl et. al.) Adequate alignment and resection guides - reproducible surgical technique – Adequate alignment and resection guides - reproducible surgical technique – no ”free hand surgery” no ”free hand surgery”

MG-UNI 98% 10 yr. Survival (loosening or revision endpoint.) 98% Good or Excellent Results -Berger, et al. CORR, 1999

Clinical Results – HSS Scores Berger RA, et al. Clin Orthop Rel Res. 1999;367: Argenson JN, et al AAOS presentation. Swienckowski, J Poster Osteopathic Specialists Meeting n=51 n= n=150 95

Clinical Results – HSS Scores Berger RA, et al. Clin Orthop Rel Res. 1999;367: Swienckowski, J Poster Osteopathic Specialists Meeting

Clinical Results – Survivorship 10-year 98% 96%95% n=62 n=160 n=187

Clinical Results – Range of Motion n=51n= º 128º

Randomised study comparing metal backed and all poly tibia Hyldahl, Regner, Carlsson, Kärrholm & Weidenhielm 1999 No difference in clinical results

Metal backed or all poly tibia?

Indications Medial OA grade I-III (Ahlbäck) - no inflammatory joint disease Medial OA grade I-III (Ahlbäck) - no inflammatory joint disease Mild To Moderate Deformity Mild To Moderate Deformity Intact ACL (?) Intact ACL (?) Minimal Patellofemoral Symptoms Minimal Patellofemoral Symptoms Age  55 yrs. (?) Age  55 yrs. (?)

Perioperative Short spinal with/without duramorph. Short spinal with/without duramorph. 1 gms.Ceflosporin I.V. prior to tourniquet inflation. 1 gms.Ceflosporin I.V. prior to tourniquet inflation.

Postoperative Compression dressing 24 h Compression dressing 24 h Full weight-bearing h postop Full weight-bearing h postop Free flexion / extension Free flexion / extension Oral pain killers Oral pain killers DVT prophylaxis for 1 month DVT prophylaxis for 1 month

SURGICAL TECHNIQUE

Miniarthrotomy Flexed knee Flexed knee Leg stabilizer Leg stabilizer 0°-120° 0°-120°

“Miniarthrotomy” Incision 8-10 cm, medial to patellar tendon Incision 8-10 cm, medial to patellar tendon

Miniarthrotomy Arthrotomy 8-10 cm Arthrotomy 8-10 cm T-incision distal to vastus medialis T-incision distal to vastus medialis Release 2 cm below joint line Release 2 cm below joint line

Femoral drilling i.m.

IM guide femur

Distal femoral cut

Distal femoral cut finished

Femur chamfer cuts

Drilling peg holes

Femur - posterior cut

Tibial resection

Tibial resection horizontal cut

Tibial resection sagittal cut

Resection posterior corner femur

Tibial sizing

Tibia - peg holes

Trial reduction, flexion

Trial reduction, extension

Cementation

Closure

UNION MEMORIAL HOSPITAL BALTIMORE, MARYLAND THANK YOU

MigrationPFC,Sledge& MG uni (tibial component ) Nilsson and Dahlen ,5 1 1,5 2 2, PFC Sledge MG uni mm months