Questionnaire survey
In total, 94 (86 males and 8 females) from 27 facilities completed the questionnaires during the study period, with a response rate of 53.7%. Fifteen doctors were from a university hospital, 74 doctors from 22 community hospitals, and five doctors from five private clinics. The mean experience as an orthopedic surgeon was mean 16.6 (1–45) years, with 22.3% in the spine, 17% in the knee, 16% in the hip, 11.7% in the upper extremity, 5.3% in the foot, and 27.7% in the other (Fig. 1). Figure 2 shows the percentage of cases of BHA and cemented stems (Fig. 2). Of the doctors, 83.0% had 11 or more BHA cases. However, 38.3% of doctors had never performed cemented stem BHA and 44.7% of doctors had 1–10 cases. Therefore, 83.0% of the doctors had fewer than 10 cases of cemented stems.
In Q.5, 97.8% of doctors answered that the cementless stem is the current first choice in BHA. The most common reason for choosing cementless fixation was familiarity with the technique (88.2%). A total of 18.1% reported fewer complications, 5.3% answered longer survival rate, and 3.2% reported good initial stability. The free description included unfamiliarity with cemented stems, not feeling the necessity of using cemented stems, and concern about pulmonary embolization with cemented stems. In Q.7, 57.4% of doctors answered that they experienced complications during the cementless stem, whereas in Q.10, only 17.0% of doctors experienced complications during the cemented stem. Table 2 shows the results of the comparison of the complication experience between the cementless and cemented stems (Table 2). Significantly more doctors experienced intraoperative or early postoperative periprosthetic fractures (75.9% vs.12.5%, p < 0.001) and subsidence (37.0% vs.0%, p = 0.003) in cementless stems. However, malposition of the implant (1.9% vs.37.5%, p < 0.001) and other complications (7.4% vs.68.8%, p < 0.001) were more common in cemented stems. Other complications included cementing techniques, such as early cement hardening and a lack of cement mantle. In Q.9, which questions in which cases the use of cemented stem is advisable, 48.9% doctors answered the wide femoral canal, 34.0% the porotic bone, 26.6% comminuted fractures, and 18.1% did not use the cemented stem in any cases. In Q.12, 60.6% of doctors answered the cement technique as concerns using cemented stems, 54.2% cement-hardened before stem insertion, 48.9% implant position, 43.6% bone cement implantation syndrome, and 21.3% longer operative time. In Q13, 3.2% doctors answered, “firstly choose cemented stem” and 11.7% answered “I will increase the cemented stem.” Therefore, most doctors still preferred using cementless stems (partly agree, I will choose cemented stem if necessary: 83.0%; only use cementless stem: 2.1%).
Table 2
Comparison of complication rates between cementless and cemented stems
| Cementless | Cemented | p value |
n | 54 | 16 | |
intraoperative or early postoperative periprosthetic fracture | 41 (75.9) | 2 (12.5) | < 0.001 |
Subsidence | 20 (37.0) | 0 (0) | 0.003 |
Loosening | 8 (14.8) | 1 (6.3) | 0.369 |
Malposition of implant | 1 (1.9) | 6 (37.5) | < 0.001 |
Others | 4 (7.4) | 11 (68.8) | < 0.001 |
Data are presented as n (%). |
In Q.14, 39.3% of doctors answered that it was possible to instruct the cemented stem (19.1% answered yes and 20.2% answered depending on the experience of the surgeon), and 91.3% of the facilities (23 facilities in total without clinics) were affiliated with the surgeon. However, 41.5% of doctors felt less experience with cemented stems, 30.9% were concerned about the management of implant malposition, and 8.5% were concerned about the management of intraoperative fractures.
In the univariate analysis to investigate factors associated with the capability of instructing cemented stem, years of experience as an orthopedic surgeon (odds ratio [OR], 1.10; p < 0.001), hip surgeon (OR, 17.82; p < 0.001), number of surgeries of BHA (OR, 2.44; p = 0.005), and number of surgeries of the cemented stem (OR, 13.31; p < 0.001) were identified. On multivariate analysis, experience as an orthopedic surgeon (OR, 1.10; p = 0.005) and the number of surgeries on cemented stems (OR, 8.42; p = 0.001) were factors affecting the ability to instruct cemented stems (Table 3). In the ROC curve analysis for the capability of instructing cemented stems and the number of surgeries using cemented stems, the best cutoff value was 1–10 cases (sensitivity, 94.4%; specificity, 58.6%), with an area under the curve of 0.8448 (95% confidence interval:0.7754–0.9142). When the cutoff value was 11–50 cases, the specificity was higher (sensitivity, 41.7%; specificity, 98.3%) (Fig. 3).
Table 3
Univariate and multivariate analyses of factors affecting the ability to instruct cemented stems
| | Univariate | | | | Multivariate | |
Variables | OR | 95%CI | p value | | OR | 95%CI | p value |
Years of experience as an orthopedic surgeon | 1.10 | 0.11–1.10 | < 0.001 | | 1.10 | 1.03–1.18 | 0.005 |
Hip surgeon | 17.82 | 4.51–119.6 | < 0.001 | | 8.39 | 1.12–92.90 | 0.052 |
Number of surgeries of BHA | 2.44 | 1.36–4.79 | 0.005 | | 1.68 | 0.83–3.57 | 0.157 |
Number of surgeries of cemented stem | 13.31 | 4.91–55.14 | < 0.001 | | 8.42 | 2.73–37.59 | 0.001 |
BHA, bipolar hemiarthroplasty; OR, odds ratio; CI, confidence interval |
A total of 226 BHA procedures were performed at nine institutions in 2021. Approximately half of the cases were single-wedge stems, and only 11 cases (4.9%) were cemented stems. (Fig. 4). All short stems were type 4, with shortened conventional tapered stems (18). There were no intraoperative fractures, but two periprosthetic fracture due to a fall from the height occurred in the single wedge stem. Dislocation occurred in two single wedge stem and one tapered rectangular stem. The infection occurred in a single wedge stem.