Early complications and causes of revision after rotating-hinge TKA

Contemporary outcomes of tibial tubercle osteotomy for revision total knee arthroplasty

Aims

Tibial tubercle osteotomy (TTO) facilitates surgical exposure and protects the extensor mechanism during revision total knee arthroplasty (rTKA). The purpose of this study was to determine the rates of bony union, complications, and reoperations following TTO during rTKA, to assess the functional outcomes of rTKA with TTO at two years' minimum follow-up, and to identify the risk factors of failure.

Methods

Between January 2010 and September 2020, 695 rTKAs were performed and data were entered into a prospective database. Inclusion criteria were rTKAs with concomitant TTO, without extensor mechanism allograft, and a minimum of two years' follow-up. A total of 135 rTKAs were included, with a mean age of 65 years (SD 9.0) and a mean BMI of 29.8 kg/m2 (SD 5.7). The most frequent indications for revision were infection (50%; 68/135), aseptic loosening (25%; 34/135), and stiffness (13%; 18/135). Patients had standardized follow-up at six weeks, three months, six months, and annually thereafter. Complications and revisions were evaluated at the last follow-up. Functional outcomes were assessed using the Knee Society Score (KSS) and range of motion.

Results

The mean follow-up was 51 months (SD 26; 24 to 121). Bony union was confirmed in 95% of patients (128/135) at a mean of 3.4 months (SD 2.7). The complication rate was 15% (20/135), consisting of nine tibial tubercle fracture displacements (6.7%), seven nonunions (5%), two delayed unions, one tibial fracture, and one wound dehiscence. Seven patients (5%) required eight revision procedures (6%): three bone grafts, three osteosyntheses, one extensor mechanism allograft, and one wound revision. The functional scores and flexion were significantly improved after surgery: mean KSS knee, 48.8 (SD 17) vs 79.6 (SD 20; p < 0.001); mean KSS function, 37.6 (SD 21) vs 70.2 (SD 30; p < 0.001); mean flexion, 81.5° (SD 33°) vs 93° (SD 29°; p = 0.004). Overall, 98% of patients (n = 132) had no extension deficit. The use of hinge implants was a significant risk factor for tibial tubercle fracture (p = 0.011).

Conclusion

TTO during rTKA was an efficient procedure to improve knee exposure with a high union rate, but had significant specific complications. Functional outcomes were improved at mid term.

Indications, clinical outcome and survival of rotating hinge total knee arthroplasty in a retrospective study of 63 primary and revision cases

PURPOSE

The purpose of this study is to report and compare outcome data of both primary and revision cases using a rotating hinge knee (RHK) implant.

METHODS

This study retrospectively analyzed 63 cases (19 primary, 44 revisions) at a mean follow-up of 34 ± 8 months after RHK implantation. Outcome parameters were stability, range of motion (ROM), loosening, Hospital of Special Surgery Score (HSS), Knee Society Score (KSS), Oxford Knee Score (OKS), EQ-5D-3L, and Visual Analog Scale (VAS) for overall function. Revision rates and implant survival are reported.

RESULTS

Eleven percent showed medio-lateral instability < 5 mm, a mean ROM of 115° ± 17° and radiologic loosening occurred in 8% (2% symptomatic). PROMS showed the following results: HSS 79 ± 18, KSS 78 ± 27, OKS 26 ± 10, EQ-5D index 0.741 ± 0.233 and VAS 70 ± 20. Primary cases revealed better outcomes in HHS (p = .035) and OKS (p = 0.047). KSS, EQ-5D index and VAS did not differ between primary and revision cases (p = 0.070; p = 0.377; p = 0.117). Revision rate was 6.3% with an implant survival of 96.8%.

CONCLUSIONS

RHK arthroplasty can be performed with good clinical outcome and low revision rate in revision and complex primary cases. RHK is an option in cases where standard arthroplasty and even implants with a higher degree of constraint have reached their limits.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

The anatomical shape of the distal femur is an independent risk factor for aseptic loosening following one-stage septic knee revision using rotating hinge knee prosthesis

PURPOSE

Aseptic loosening (AL) is the second most common reason for failure after one-stage septic knee revision. In this context, the goal of the study is to identify risk factors for AL following one-stage septic knee revision using rotating hinge implants. We aimed to answer the following research question: How does the anatomical shape of the distal femur represent an independent risk factor for AL following one-stage septic knee revision arthroplasty?

METHODS

Patients, who had undergone re-revision surgery due to AL of the rotating hinge knee prosthesis after one-stage septic knee revision arthroplasty between January 2008 and December 2018, were included. For this purpose, 41 patients with AL after one-stage septic knee revision using rotating hinge implants and 37 controls without any revision surgery at latest follow-up were included in this study. Using standardized anteroposterior (AP) views of the knee in all patients, we measured the inner diameter of the femur 20 cm proximally from the joint line and at a point 2 cm proximally from the adductor tubercle.

RESULTS

Among the vast majority of AL cases, we identified an isolated loosening of the femoral component. The AL group showd a high distribution of the Type C according to the Citak classification with 75.7%. Contrary to this, with 24.3% (p < 0.001) the amount of Type C cases was relatively low in the control group. Consequently, Type C configurations of the distal femur represent an independent risk factor for AL with an approximately sevenfold higher risk for AL compareed to Type A and Type B.

CONCLUSIONS

The novel radiological classification system of the distal femur shows that the Type C subtype is an independent and main risk factor for AL after one-stage septic knee revision using rotating hinge knee implants.

Preoperative mechanical axis has no influence on reoperation rate in primary rotating-hinge knee arthroplasty

Background

The purpose of the study is to evaluate reoperation rate and its relationship to preoperative mechanical axis of rotating-hinge TKA used as the primary implant in complex knees.

Methods

Patients subjected to primary TKA with a rotating-hinge knee prosthesis due to primary osteoarthritis between 2010 and 2019 were retrospectively reviewed. Preoperative mechanical axis was measured using the last preoperative telemetry x-ray image. Preoperative axis was classified according to the type of deformity (varus or valgus) and its magnitude (0-15°, 16-25° or >25°). Reoperation rate (with or without implant removal) was the primary outcome of the current study. We studied if the preoperative mechanical axis (either varus-valgus, or magnitude of malalignment) was related to implant survival rate.

Results

Forty-two patients were included in the study. Mean follow-up was 51.42 ± 31.88 months. The 83.3% of patients presented a valgus axis while the 16.7% presented a varus axis. Need of reoperation occurred in eight patients (19.0%). However, no patients (0%) required implant removal with revision TKA. No association was seen between the preoperative mechanical axis and risk of reoperation (p = 0.16).

Conclusion

In selected situations that do not permit less constrained implants, primary rotating-hinge arthroplasty could be a good alternative. Risk of reoperation does not seem to depend upon the preoperative mechanical axis when using a rotating-hinge knee prosthesis for primary arthroplasty in non-tumoral complex knees.

What Is the Mid-term Survivorship of Infected Rotating-hinge Implants Treated with One-stage-exchange?

BACKGROUND

Despite the growing number of studies reporting on periprosthetic joint infection (PJI), there is little information on one-stage exchange arthroplasty for the revision of infected rotating-hinge prostheses, which can be among the most difficult PJI presentations to treat.

QUESTIONS/PURPOSES

After one-stage direct exchange revision for an infected rotating-hinge TKA prosthesis, and using a multimodal approach for infection control, we asked: (1) What is the survivorship free from repeat revision for infection and survivorship free from reoperation for any cause? (2) What is the clinical outcome, based on the Oxford Knee Score, of these patients at the latest follow-up?

METHODS

Between January 2011 and December 2017, we treated 101 patients with infected rotating-hinge knee prostheses at our hospital. All patients who underwent a one-stage exchange using another rotating-hinge implant were potentially eligible for this retrospective study. During that period, we generally used a one-stage approach when treating PJIs. Eighty-three percent (84 of 101) of patients were treated with one-stage exchange, and the remainder were treated with two-stage exchange. Of the 84 treated with one-stage exchange, eight patients died of unrelated causes and were therefore excluded, one patient declined to participate in the study, and another eight patients were lost before the minimum study follow-up of 2 years or had incomplete datasets, leaving 80% (67 of 84) for analysis in this study. The included study population consisted of 60% males (40 of 67) with a mean age of 64 ± 8 years and a mean (range) BMI of 30 ± 6 kg/m2 (21 to 40). The mean number of prior surgeries was 4 ± 2 (1 to 9) on the affected knee. Fifteen percent (10 of 67) of knees had a preoperative joint communicating sinus tract, and 66% (44 of 67) had experienced a prior PJI on the affected knee. The antimicrobial regimen was chosen based on the advice of our infectious disease consultant and individually adapted for the organism cultured. The mean follow-up duration was 6 ± 2 years. Kaplan-Meier survivorship analysis was performed using the endpoints of survivorship free from repeat revision for infection and survivorship free from all-cause revision. The functional outcome was assessed using the Oxford Knee Score (on a 12- to 60-point scale, with lower scores representing less pain and greater function), obtained by interviewing patients for this study at their most recent follow-up visit. Preoperative scores were not obtained.

RESULTS

The Kaplan-Meier analysis demonstrated an overall survivorship free from reoperation for any cause of 75% (95% CI 64% to 87%) at the mean follow-up of 6 years postoperatively. Survivorship free from any repeat operative procedure for infection was 90% (95% CI 83% to 97%) at 6 years. The mean postoperative Oxford Knee Score was 37 ± 11 points.

CONCLUSION

With an overall revision rate of about 25% at 6 years and the limited functional results based on the poor Oxford Knee Scores, patients should be counseled to have modest expectations concerning postoperative pain and function level after one-stage exchange of an infected rotating-hinge arthroplasty. Nevertheless, patients may be informed about a reasonable chance of PJI eradication and might opt for this approach as a means to try to avoid high transfemoral amputation or joint arthrodesis, which in this population often is associated with the inability to ambulate at all. Regarding the relatively high number of patients with aseptic loosening, future studies might focus on implant design of revision knee systems as well. A longer course of oral antibiotics after such procedures may also be warranted to limit the chance of reinfection but requires further study.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

Complications and failures of non-tumoral hinged total knee arthroplasty in primary and aseptic revision surgery: A review of 290 cases

INTRODUCTION

Hinged total knee arthroplasty (TKA) implants are a commonly used option during revision or even primary surgery, but their complications are not as well known, due to the rapid adoption of gliding implants. The literature is inconsistent on this topic, with studies having a small sample size, varied follow-up duration and very different indications. This led us to carry out a large multicentre study with a minimum follow-up of 5 years to evaluate the complications after hinged TKA in a non-tumoral context based on the indications of primary arthroplasty, aseptic surgical revision or fracture treatment around the knee.

HYPOTHESIS

Hinged TKA was associated with a high complication rate, no matter the indication.

MATERIAL AND METHODS

Two hundred and ninety patients (290 knees) were included retrospectively between January 2006 and December 2011 at 17 sites, with a minimum follow-up of 5 years. The patients were separated into three groups: primary surgery (111 patients), aseptic revision surgery (127 patients) and surgery following a recent (<3 months) fracture (52 patients: 13 around the TKA and 39 around the knee treated by hinged TKA). Patients who had an active infection the knee of interest were excluded. All the patients were reviewed based on a standardised computer questionnaire validated by the SOFCOT.

RESULTS

The mean follow-up was 71±39 months [range, 0 to 188]. Of the 290 patients included in the study, 108 patients (37%) suffered at least one complication and 55 patients (19%) had to undergo revision surgery: 16 in the primary TKA group (16/111, 14% of primary TKA), 28 in the revision surgery group (28/127, 22% of revision TKA) and 11 in the fracture treatment group (11/52, 21% of fracture TKA). The complications due to the hinged TKA for the entire cohort from most to least common were stiffness (41/290, 14%), chronic postoperative pain (37/290, 13%), infection (32/290, 11%), aseptic loosening (23/290, 8%), general complications (20/290, 7%), extensor mechanism complications (19/290, 6%), periprosthetic fracture (9/290, 3%), mechanical failure (2/290, 0.7%). In the primary TKA group, the main complication leading to re-operation was infection (12/111, 11%), while it was loosening for the revision TKA group (15/127, 12%) and infection (8/52, 15%) for the fracture TKA group.

DISCUSSION

The 37% complication rate for hinged TKA implants is high, with 19% of them requiring re-operation. The frequency of complications differed depending on the context in which the hinged implant was used (primary, revision, fracture). The complications requiring revision surgery were major ones that prevented patients from preserving their autonomy (infection, symptomatic loosening, fracture, implant failure). The most found complications - stiffness and chronic pain - rarely led to revision.

LEVEL OF EVIDENCE

IV; retrospective cohort study.

Spherical center axial hinge knee prosthesis causes lower contact stress on tibial insert and bushing compared with biaxial hinge knee prosthesis

BACKGROUND

Motion axial system may affect contact stress of hinge knee prosthesis. However, it is unclear which axial system provides the better biomechanical effect. Therefore, the aim of this study was to compare the contact stress and stress distribution on the tibial insert and the bushing of hinge knee prostheses with a biaxial (BA) system and a spherical center axial (SA) system during a gait cycle.

METHODS

Three-dimensional finite-element (FE) models of the prostheses with different motion systems were included. The comparisons between experimental tests and FE analyses were performed to verify the models. Dynamic implicit FE analyses were performed to investigate the peak contact stresses and stress distributions on the tibial insert and the bushing.

RESULTS

The peak contact stresses on the tibial insert and the bushing of the BA prosthesis were higher than those of the SA prosthesis during most gait cycles. The contact time on the bushing is short in the SA prosthesis. The stress distributions on the superior surface of the tibial insert in the BA prosthesis were at the posterior side, but of the SA prosthesis were not fixed.

CONCLUSION

The SA prosthesis has a lower peak contact stress on tibial insert and bushing than the BA prosthesis; in addition, the SA prosthesis has a 'self-adjustment' mechanism which could disperse high stress on the tibial insert to decrease the risk of wear and damage. The comparison could help designers and surgeons to better understand the future design of rotating hinge knee prostheses which should be able to achieve multiaxial motion and complete weight bearing by the tibial condylar to transmit the axial force better.