Clin Orthop Surg.  2014 Dec;6(4):365-372. 10.4055/cios.2014.6.4.365.

Complications of Medial Unicompartmental Knee Arthroplasty

• Ji JH
• Park SE
• Song IS
• Kang H
• Ha JY
• Jeong JJ

• KMID: 1794722
• DOI: http://doi.org/10.4055/cios.2014.6.4.365

Abstract

BACKGROUND
We report intra- and postoperative complications of unicompartmental knee arthroplasty (UKA).
METHODS
This study was conducted on 246 cases of UKA which were performed for degenerative osteoarthritis confined to the medial compartment, from May 2002 to May 2010, for which follow-up periods longer than one year were available. Complications were divided into intra- and postoperative complications. Pre- and postoperative clinical scores, the range of motion, and radiologic findings were analyzed.
RESULTS
Complications developed in a total of 24 cases (9.8%, 24/246). Among them, 6 cases had intraoperative complications while 18 had postoperative complications. Among the 6 intraoperative complications, one fracture of the medial tibial condyle, two fractures of the intercondylar eminence, one rupture of the medial collateral ligament, one widening of the peg hole leading to femoral component malposition and late failure, and one total knee arthroplasty (TKA) conversion of a large bony defect of tibial avascular necrosis were observed. Among the 18 postoperative complications, four cases of aseptic loosening of the femoral component, one soft tissue impingement due to malalignment, nine cases of polyethylene bearing dislocation, one case of suprapatellar bursitis, one periprosthetic fracture, one TKA conversion due to medial component overhanging, and one TKA conversion due to pain of unexplained cause were observed.
CONCLUSIONS
The mid-term clinical outcomes of UKA were excellent in our study. However, the incidence of complications was very high (9.8%). To prevent intra- and postoperative complications, proper selection of the patients and accurate surgical techniques are required.

Keyword

Unicompartmental knee arthroplasty; Intraoperative complications; Postoperative complications

MeSH Terms

Aged
Arthroplasty, Replacement, Knee/*adverse effects/methods
Female
Humans
Intraoperative Complications
Male
Middle Aged
Osteoarthritis, Knee/radiography/*surgery
Postoperative Complications
Retrospective Studies

Figure

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  Fig. 1 A 3-mm dislocated bearing (A, B) was replaced with an 8-mm thick bearing (C), resulting in an increase of the valgus angle from 8.5° (A) to 12.6° (C). The final follow-up radiograph showed reduction of the valgus angle from 12.6° (C) to 9° (D).

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  Fig. 2 A dislocated bearing (A) was replaced with a thicker bearing (B). Posterior bearing dislocation recurred after the revision of bearing dislocation (C), but spontaneous reduction of the dislocated bearing was observed (D).

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  Fig. 3 (A) A 5-mm overhang of the medial compartment caused irritation of the medial aspect of the knee, resulting in cellulitis-like symptoms. (B) A 3-phase bone scan of the right knee showed some increased radioisotope uptake on all three phases. (C) Sixteen months later, a conversion to total knee arthroplasty was performed.

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  Fig. 4 (A) Recurrent suprapatellar bursitis developed along the hemovac site (arrow). (B) Open excision was performed 4 months later.

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  Fig. 5 Because of the severe unexplained pain in a 69-year-old female (A), conversion to total knee arthroplasty was performed at 2 months postsurgery (B).

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