Table 2 Summary of clinical outcomes for each of the studies enrolled in this review

Remily et al (2021) [15]

KSS, complications, survivorship

Mean postoperative KSS were significantly higher when compared with preoperative KSS (80.4 vs 52.0; p>.001)

Seven surgeries were performed involving the explantation of 8 cones, eleven additional knee surgeries not involving the cone were performed

Survivorship was 98.5% when the endpoint was cone revision due to aseptic loosening. When the endpoint was considered cone revision for any reason, survivorship was 88.2%. Cone survivorship was 77.9% for any reoperation of the knee

Kong et al (2021) [16]

Operation time, blood loss, KSS, ROM, reinfection rate, satisfaction rate

The average operation time for the static group was 119 minutes (range, 75-150 minutes), whereas the average intraoperative blood loss was 439 ml (range, 250-650 ml)

The average operative time of the articulating group was 98 minutes (range, 65-135minutes), whereas the average intraoperative bleeding level was 358 ml (range, 150-600 ml)

The KSS score of patients in the static group was not significantly different from KSS score of patients in the articular group during admission

After the second-stage revision, average ROM in the static group was 80° (70°~110°), whereas the average ROM in the articular group was 94° (80°~115°)

The reinfection rate in static group was (1/22), whereas in articular group was (1/20), and there was no significant difference between two group (p=0.95)

After the final revision surgery, 55 % (12/22) of patients in the static group were satisfied with overall treatment, whereas 90% (18/20) of patients in the articular group were satisfied with overall treatment

Tetreault et al (2020) [18]

KSS, survivorship, complications

The mean KSS improved from 50 (0 to 94) preoperatively to 87 (72 to 94) at the most recent follow-up (p < 0.001)

At two years, survivorship free of cone revision for aseptic loosening was 100% and free of any cone revision was 98% (95% CI = 95% to 100%). Two- year survivorship free of any revision was 90% (95% CI = 86% to 96%), and free of any reoperation was 83% (95% CI = 77% to 90%)

Two patients had three intraoperative complications related to cone placement. There were two distal femoral fractures with implant removal and one partial patellar tendon avulsion during exposure. There were two instances of recurrent PJI and one of partial wound dehiscence managed non-operatively. additionally, one patient had a nonfatal pulmonary embolism postoperatively

Durand et al (2020) [19]

OHS, post-operative walking status, complications

Mean OHS at latest follow up was 32.4 (S.D 10.4)

There were eight patients need crutches, one patient need wheelchair, five patients were walking independent, five patients were unilateral walking stick, and one patient need frame

One patient occurred periprosthetic fracture, and required revision

Wan et al (2019) [20]

HSS, VAS, SF-36

There was no significant difference in HSS between the two groups before operation (p>0.05). At 3, 6 and 12 months after operation, HSS of the observation group were significantly higher than those of the control group (p<0.05)

There was no significant difference in VAS score

between the groups before operation (p>0.05). VAS scores of the observation group were significantly lower than those of the control group at 3, 6 and 12 months after operation (p<0.05)

There was no significant difference in SF-36 scores between the two groups before treatment (p>0.05). The SF-36 scores of the observation group were significantly higher than those of the control group at 3, 6 and 12 months after treatment (p<0.05)

Li et al (2019) [21]

Operation time, blood loss, blood transfusion, HSS, complications

The mean operation time was 254 ± 91 min

The blood loss was 891 ± 423 ml

The mean blood transfusion was 860 ± 400 ml

The mean HHS was significantly improved from 27.50 ± 6.54 preoperatively to 80.94 ± 5.19 at final follow-up (p<0.001)

Two cases had intraoperative periprosthetic femoral fracture

Kieser et al (2018) [22]

OHS, HSS, WOMAC, complications

3 patients reported no disability (OHS 60), 15 excellent outcomes (OHS >50), 11 a good outcome (OHS 40-50) and 6 a fair outcome (OHS 30-40)

2 patients were reported to be doing poorly (OHS 29 and 27 respectively) at >2 years follow-up.

1 patient had early implant migration with subsequent stabilization. 2 patients had radiographs concerning for failure of osteointegration. 1 patient had recurrent dislocations.

Li et al (2016) [23]

HSS, complications

HSS scores improved from a mean of 36 before surgery (SD, 8; range, 20–49) to 82 at latest follow-up (SD,18; range, 60–96; p<0.001)

Infections developed in two hips, and one dislocation case

Mao et al (2015) [24]

HSS, complications, survivorship

The mean HSS score improved from 39.6 (range, 12–60) pre-operatively to 80.9 (range, 53–93) at the final follow-up (p<0.01)

One patient who had an intra-operative rupture of the superior acetabular artery, and two patients experienced dislocation

The survival of the cage with revision for any reason was 91.30 % (95 % CI 58.10–73.95) and with aseptic loosening as the endpoint was 95.66 % (95 % CI 63.10–74.81)