Analysis of the causes of primary revision after unicompartmental knee arthroplasty: A case series

Abstract

Background: Unicompartmental knee arthroplasty (UKA) has great advantages in the treatment of unicompartmental knee osteoarthritis, but its revision rate is higher than that of total knee arthroplasty.

Aim: To summarize and analyse the causes of revision after UKA.

Methods: This is a retrospective case series study in which the reasons for the first revision after UKA are summarized. We analysed the clinical symptoms, medical histories, laboratory test results, imaging examination results and treatment processes of the patients who underwent revision and summarized the reasons for primary revision after UKA.

Results: A total of 13 patients, including 3 males and 10 females, underwent revision surgery after UKA. The average age of the included patients was 67.62 years. The prosthesis was used for 3 d to 72 months. The main reasons for revision after UKA were improper suturing of the surgical opening (1 patient), osteophytes (2 patients), intra-articular loose bodies (2 patients), tibial prosthesis loosening (2 patients), rheumatoid arthritis (1 patient), gasket dislocation (3 patients), anterior cruciate ligament injury (1 patient), and medial collateral ligament injury with residual bone cement (1 patient).

Conclusion: The causes of primary revision after UKA were gasket dislocation, osteophytes, intra-articular loose bodies and tibial prosthesis loosening. Avoidance of these factors may greatly reduce the rate of revision after UKA, improve patient satisfaction and reduce medical burden.

Keywords: Case series; Causes; Revision; Total knee arthroplasty; Unicompartmental knee arthroplasty.

Figure 1

Treatment process (right knee) for Patient 1. A: Anteroposterior X-ray before revision; B: Lateral X-ray before revision; C: Surgical opening before revision; D: Incision for revision; E: The incision healed well after revision.

Figure 2

Treatment process (right knee) for Patient 3. A: Anteroposterior X-ray before revision; B: Dual computed tomography image showing osteophytes in front of the femoral prosthesis; C: Osteophytes in front of the femoral prosthesis; D: Excision of osteophytes; E: Anteroposterior X-ray after revision.

Figure 3

Treatment process (left knee) for Patient 5. A: Dual computed tomography image showing that there was a bone-free body between the tibial prosthesis and the femoral prosthesis; B: Residual bone cement was found during arthroscopic exploration.

Figure 4

Treatment process (right knee) for Patient 6. A: Anteroposterior X-ray before revision; B: Lateral X-ray before revision; C: The tibial prosthesis was loose; D: The tibial prosthesis was easily removed during revision; E: The femoral prosthesis was removed and modified for total knee arthroplasty.

Figure 5

Treatment process (right knee) for Patient 8. A: A large amount of inflammatory synovium in the suprapatellar bursa was observed during revision; B: The lateral femoral condyle cartilage was injured; C: Synovial tissue; D: Oxford movable platform single condyle prosthesis.

Figure 6

Treatment process (right knee) for Patient 9. A: Lateral X-ray before unicompartmental knee arthroplasty (UKA); B: Lateral X-ray in the weight-bearing position after UKA.

Figure 7

Treatment process (left knee) for Patient 12. A: Before revision, X-ray showed that the gasket was dislocated; B: The spacer was moved forward under extreme knee flexion; C: The centre of the femoral prosthesis was inwards; D: Prosthesis displacement; E: X-ray after revision.

Figure 8

Treatment process (left knee) for Patient 13. A: X-ray image showing genu valgus after Unicompartmental knee arthroplasty (UKA); B: X-ray showing residual bone cement after UKA; C: Repair of the medial collateral ligament; D: X-ray anteroposterior films after revision.