Total Knee Arthroplasty in Hemophilic Arthropathy

Mean KSS Knee score improved from 79 before surgery to 36 after surgery, and mean KSS Function score improved from 63 to 33. KSS Pain score, which is included in the Knee score, 0 (no pain) to 50 (most severe pain), improved from 47 to 8. Patients receiving inhibitors and patients who were HIV- or HCV-positive did not have poorer outcomes relative to those of patients not receiving inhibitors and patients who were HIV- or HCV-negative. Patients with liver cirrhosis had a lower prosthetic survival rate and lower Knee scores.

Discussion

The prosthetic survival rate found in this study compares well with other reported rates for patients with hemophilia and other bleeding disorders. However, evidence regarding long-term prosthesis survival in TKAs performed for patients with hemophilia is limited. Table 3 summarizes the main reported series of patients with hemophilia with 10-year prosthetic survival rates, number of TKAs performed, and mean follow-up period; in all these series, implant removal for any reason was regarded as the final endpoint.^5-8,16,17 Mean follow-up in our study was 8 years. Clinical outcomes of TKA in patients with severe hemophilia and related disorders are expected to be inferior to those achieved in patients without a bleeding condition. The overall 10-year prosthetic survival rate for cemented TKA implants, as reported by the Norwegian Arthroplasty Register, was on the order of 93%.¹⁸ Mean age of our patients at time of surgery was only 38.2 years. TKAs performed in younger patients without a bleeding disorder have been associated with shorter implant survival times relative to those of elderly patients.¹⁹ Thus, Diduch and colleagues²⁰ reported a prosthetic survival rate of 87% at 18 years in 108 TKAs performed on patients under age 55 years. Lonner and colleagues²¹ reported a better implant survival rate (90% at 8 years) in a series of patients under age 40 years (32 TKAs). In a study by Duffy and colleagues,²² the implant survival rate was 85% at 15 years in patients under age 55 years (74 TKAs). The results from our retrospective case assessment are quite similar to the overall prosthetic survival rates reported for TKAs performed on patients without hemophilia.

Rates of periprosthetic infection after primary TKA in patients with hemophilia and other bleeding conditions are much higher (up to 11%), with a mean infection rate of 6.2% (range, 1% to 11%), consistent with the rate found in our series of patients (6.8%)^{7,16,17,23,24} (Table 4). This rate is much higher than that reported after primary TKA in patients without hemophilia but is similar to some rates reported for patients with hemophilia. In our experience, most periprosthetic infections (5/6) were sorted as late.

Late infection is a major concern after TKA in patients with hemophilia, and various factors have been hypothesized as contributing to the high prevalence. An important factor is the high rate of HIV-positive patients among patients with hemophilia—which acts as a strong predisposing factor because of the often low CD4 counts and associated immune deficiency,²⁵ but different reports have provided conflicting results in this respect.^5,6,12 We found no relationship between HIV status and risk for periprosthetic infection, but conclusions are limited by the low number of HIV-positive patients in our series (14/74, 18.9%). Our patients’ late periprosthetic infections were diagnosed several years after TKA, suggesting hematogenous spread of infection. Most of these patients either were on regular prophylactic factor infusions or were being treated on demand, which might entail a risk for contamination of infusions by skin bacteria from the puncture site. Therefore, having an aseptic technique for administering coagulation factor concentrates is of paramount importance for patients with hemophilia and a knee implant.

Another important complication of TKA surgery is aseptic loosening of the prosthesis. Aseptic loosening occurred in 2.2% of our patients, but higher rates have been reported elsewhere.^11,26 Rates of this complication increase over follow-up, and some authors have linked this complication to TKA polyethylene wear.²⁷ Development of a reactive and destructive bone–cement interface and microhemorrhages into such interface might be implicated in the higher rate of loosening observed among patients with hemophilia.²⁸

In the present study, preoperative and postoperative functional outcomes differed significantly. A modest postoperative total ROM of 69º to 79º has been reported by several authors.^5,6 Postoperative ROM may vary—may be slightly increased, remain unchanged, or may even be reduced.^4,23,26 Even though little improvement in total ROM is achieved after TKA, many authors have reported reduced flexion contracture and hence an easier gait. However, along with functional improvement, dramatic pain relief after TKA is perhaps the most remarkable aspect, and it has a strong effect on patient satisfaction after surgery.^5,7,8,18,23