Primary Arthroplasty
Rotating Hinge Implants for Complex Primary and Revision Total Knee Arthroplasty

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Abstract

Background

Contemporary rotating hinge knee (RHK) prosthesis has shown improved survival rates over earlier generations. However, reports of high complication and mechanical failure rates highlight the need for more clinical outcome data in the complex primary and revision setting. The purpose of this study is to report our results of using a contemporary rotating hinge for complex primary and revision total knee arthroplasty.

Methods

Using a prospectively maintained surgical database, 79 knees in 76 patients who underwent an RHK of a single design for either a complex primary (14 knees) or revision total knee arthroplasty (65 knees) were identified. This included 19% undergoing an RHK for periprosthetic joint infection and 32.9% who had concomitant extensor mechanism repair. The cohort consisted of 60 women and 16 men with a mean age of 66.7 years (range 39-89) at the time of surgery. Patient outcomes were assessed using Knee Society Scores and radiographs were reviewed for signs of wear and loosening. Failure rates were estimated using Kaplan-Meier survival curves.

Results

At a minimum of 2 years, 13 patients had died and 4 were lost to follow-up, leaving 62 knees in 59 patients who were followed for a mean of 55.2 months (range 24-146). The mean Knee Society Scores improved from 35.7 to 66.2 points (P < .01). The incidence of complications was 38.7%. The most common complications were periprosthetic fracture, extensor mechanism rupture, and periprosthetic infection. Estimated survival was 70.7% at 5 years.

Conclusion

Despite improvements in design and biomaterials, there remains a relatively high complication rate associated with the use of a modern RHK implant. While aseptic loosening was rare, periprosthetic fracture, infection, and extensor mechanism failure were substantial emphasizing the complex nature of these cases.

Section snippets

Methods

After institutional review board approval, the database of the senior authors, all fellowship trained in adult reconstruction, was queried for cases using an RHK of a single design (NexGen RHK; Zimmer, Warsaw, IN), between the years 2003 and 2014. Inclusion criteria were all nononcological primary and revision indications. Exclusion criteria were cases involving the use of a distal femoral replacement (15 procedures).

There were 79 knees in 76 patients who underwent an RHK for either a complex

Results

At a minimum of 2 years, 13 patients had died and 4 were lost to follow-up leaving 62 knees in 59 patients who were followed for a mean of 55.2 months (range 24-146). This included 8 failures prior to 2 years. There were no known complications among the 4 patients who were lost to follow-up prior to 2 years (mean follow-up 6 months, range 1-13). Similarly, the mean follow-up among the 13 patients who died without a minimum of 2-year clinical follow-up was 6.8 months (range 1-18) with no known

Discussion

Hinged knee implants are a powerful tool in the knee surgeon's armamentarium; however, there is hesitation over their use given few reports that describe outcomes of contemporary designs. Specific concerns include high forces at the fixation interfaces and bearing surfaces although we found these complications to be rare. That being said, the overall complication rate in this complex series of patients was high.

We found an overall postoperative complication rate of 38.7%, which is relatively

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    In France, the HKA angle is used to estimate the cost of the procedure and therefore the cost reimbursed by the statutory health insurance system. The HKA angle also directs the choice of the surgical approach and, in patients with marked deformities, allows anticipation of the need for a semi-constrained or hinged prosthesis [9–12] After TKA, the LSR serves to check the coronal alignment of the lower limb, the goal in terms of mechanical axis alignment being a value of 180° ± 3° to minimise the risk of mechanical loosening [13,14]. However, numerous factors can influence the value of the HKA angle on the LSR, including rotation of the hip and/or leg and lower limb deformities in the sagittal plane (flexion or recurvatum deformity) [15–18].

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One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to https://doi.org/10.1016/j.arth.2017.10.009.

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