Role of metaphyseal sleeves in revision total knee arthroplasty: Rationale, indications and long-term outcomes

Abstract

Metaphyseal sleeves have become an integral part of surgeons’ armamentarium in dealing with complex revision knee arthroplasty. They offer the advantages of addressing bone defects with biological fixation techniques, efficient surgical preparation providing a stable tibial platform which optimises joint line positioning and gap balancing leading to excellent long-term survivorship and clinical outcomes. Here, we review the concept of metaphyseal fixation, indications of metaphyseal sleeves and their limitations with our surgical tips on how to remove well-fixed sleeves. We also present our tertiary experience and review clinical outcome studies of metaphyseal sleeves in revision knee arthroplasty literature.

1. Introduction

The concept of metaphyseal sleeve fixation is to use an intramedullary device to enhance metaphyseal and diaphyseal fit, promote intramedullary load sharing, fixation into intact bone, and to bypass stress risers in situations of bone deficiencies. It was featured in the third generation S-ROM mobile-bearing hinge total knee prosthesis (DePuy, Warsaw, IN) in response to the high failure rates seen in earlier hinge designs; among other modifications. Metaphyseal sleeves are stepped and coated with titanium beads allowing for bone ingrowth^1,2 and fixed with a Morse taper junction to either the femoral or tibial component (Fig. 1). In 2001, Jones & Barrack et al.³ reported on their combined series of modular, mobile-bearing hinged knee arthroplasties with metaphyseal sleeves for salvage cases with good midterm outcomes and notable success of the sleeves. Hence, further engineering developments have resulted in the use of metaphyseal sleeves with semi-constrained mobile-bearing revision implants. Since then, the use of metaphyseal sleeves has gained popularity with numerous clinical series demonstrating excellent osseointegration and survivorship at short-to medium-term and more recently medium-to long-term follow up.4, 5, 6, 7, 8

Fig. 1.

Femoral and tibial partially coated sleeves (DePuy Synthes, Warsaw, IN).

In this article, we review the indications, limitations and outcomes of metaphyseal sleeves in revision knee arthroplasty and present our experience/clinical outcomes.

1.1. Rationale and indications

Success of revision total knee arthroplasty (rTKA) relies on achieving a stable revision construct that can address bone loss and allow early mobilisation.⁹ Significant bone loss is often encountered during rTKA either due to periprosthetic failure, osteolysis or during removal of well-fixed components. Earlier revision systems used long stems to transmit the load to the diaphysis and relied on epiphyseal-diaphyseal fixation in order to achieve epiphyseal loading surface which included cement or augments to build the tibial plateau in order to support the components.^10,11 Whilst this approach had some success, it led to stress shielding of the proximal tibia and high incidence of “stem tip pain” which can worsen the outcome of revision surgery.^12,13

The metaphyseal bone is well-vascularised and often spared the damage seen in epiphyseal bone during revision surgery. This offers advantage for cement interdigitation or implant osteointegration.¹⁴ The early success with metaphyseal sleeves in mobile-bearing hinged knee arthroplasties lent itself to semi-constrained revision designs (Press-Fit Condylar (PFC), Total Condylar 3 (TC3) and Low Contact Stress (LCS), DePuy, Warsaw, IN). Once osseointegrated, sleeves transfer the load to the metaphysis protecting the epiphyseal fixation and improving the rotational stability of the construct. It is superior in doing so compared to the fluted cylindrical stems.¹⁵ Furthermore, sleeves have the added advantage of being used as instruments during surgery. Similar to the preparation of the proximal femur during uncemented hip arthroplasty, the canal is reamed and broached to achieve rotational and axial stability. Once the metaphysis is filled, this offers a stable cutting platform negating the need for pinning jigs and cutting guides. The bony cuts can be made, efficiently ensuring appropriate alignment, directly off the metaphyseal broach attached to a trail stem of desired length. We use stems to provide immediate support whilst the porous coated sleeve, once osseointegrated, provides the long-term support to the construct.

Metaphyseal sleeves are integral parts of the rTKA construct. This is the main difference between sleeves and trabecular metal cones (Zimmer, Warsaw, IN). Although cones are of porous tantalum with favourable porosity, high coefficient of friction and low stiffness with high rate of osteointegration,¹⁶ they require fixation or “unitisation” to the revision components by a cemented interface. Therefore, they act as a “metallic bone graft” and separate to implant fixation (see Fig. 2a, Fig. 2ba-b Fig. 3a, Fig. 3ba-b Fig. 4).

Fig. 2a.

Anteroposterior weight-bearing and lateral radiographs of a 75 years old patient demonstrating an uncontained defect with medial tibial bone loss.

Fig. 2b.

Postoperative radiographs following reconstruction with tibial metaphyseal sleeve/press fit stem construct demonstrating bone ongrowth and long term osteointegration; (a) immediate postoperatively, (b) at 1-year, (c) at 5-year and (d) at 7-year follow up.

Fig. 3a.

Anteroposterior and lateral radiographs of 83 years old patient with catastrophic polyethylene failure, osteolysis of the proximal tibia and instability.

Fig. 3b.

Postoperative radiographs following reconstruction with well-fixed tibial and femoral metaphyseal sleeves and a rotating hinge construct; (a) at 1-year and (b) 3-year follow up.

Fig. 4.

Example of long-term follow up of 62 years old patient who underwent revision knee arthroplasty for aseptic loosening with tibial metaphyseal sleeve reconstruction at (a) 2-year, (b–c) 12-year and (d) 14-year follow up.

The Anderson Orthopaedic Research Institute (AORI) classification system, developed by Engh, is widely used to classify bone loss both pre- and intra-operatively.¹⁷ Smaller defects (AORI-I) can be managed with cement or localised bone grafts. Larger defects with damaged or deficient metaphyseal bone (AORI-II/III) can be managed with metal augmentation (sleeves or cones), structural allografts or impaction grafting and in severe cases with condylar replacing prostheses when the defect is uncontained.18, 19, 20 We have been using metaphyseal sleeves routinely since 2005 for large contained defects (AORI-II/III). On the tibial side, we routinely use a press-fit cementless stem with a metaphyseal sleeve in all cases. On the femoral side, we aim to reconstruct the joint line, with augments if needed, and either a cementless press-fit stem or more commonly a short cemented femoral stem. We use femoral sleeves to address significant metaphyseal defects. This approach ensures fixation of the components to the metaphysis and diaphysis. This applies to aseptic revisions as well as septic revisions with 2-stage approach (Fig. 5a, Fig. 5b).

Fig. 5a.

Example of metaphyseal sleeve reconstructing in septic revisions; (a) significant metaphyseal defect of proximal tibia; (b) immediate postoperative radiograph; (c) 1-year follow up with well-fixed construct.

Fig. 5b.

Subsequent follow up radiographs at (a) 2-year, (b) 4-year and (c) 6-year follow up.

1.2. Limitations

Metaphyseal sleeves require enough contact with host bone to achieve primary stability with axial and rotational stability. In cases of uncontained defects or deficient proximal tibiae or more commonly condylar deficiency in the distal femur, endoprostheses (proximal tibial replacement or distal femoral replacement) may be necessary for a stable construct. Interestingly, however, a recent retrieval study of bone ongrowth distribution of metaphyseal sleeves in revision arthroplasty found that sufficient fixation can be achieved with only limited amounts of bone ongrowth (14.7% in tibial sleeves and 21.3% in femoral sleeves).²¹

1.3. Removal of well-fixed sleeves

Removal of well-fixed metaphyseal sleeves is challenging although rarely indicated. Our approach is to firstly to disrupt the cement bone interface then to disengage the Morse taper connection (sleeve/component) using either an especially designed separator on the tibial side or a disimpacting punch on the femoral side. The component is then removed allowing intramedullary access to the sleeve, akin to cementless femoral hip replacement stem. However, if the Morse taper cannot be disengaged then extensile approaches such as an extended tibial crest osteotomy should be used to allow direct access to the tibial sleeve.

1.4. Our tertiary experience

In our single-surgeon series, we reported on the outcomes of metaphyseal sleeves of 319 rTKA over 10 year period (2006–2016) with minimum 2 year follow up.⁴ We use the DePuy Synthes revision TKA system which consists of different levels of constraint. The PFC Sigma Posterior Stabilized is the least constrained, but allows the attachment of stems and sleeves if required. Next is the TC3-RP which is a varus-valgus constrained device with a more constrained cam and post mechanism and a highly conforming mobile bearing. Finally, the S-ROM Noiles rotating hinge is used when there is ligamentous deficiency or a gross flexion-extension mismatch, and the Limb Preservation System (LPS) distal femoral replacement is reserved for large bony defects or periprosthetic fractures. All these femoral options are compatible with the mobile bearing tibia (MBT) rotating platform revision tibial component and the metaphyseal sleeve system. All 319 revisions had a tibial metaphyseal sleeve to address the central bone loss associated with removal of the tibial component and 146 had femoral sleeves. Where there was significant bone loss on the femur, a femoral metaphyseal sleeve was used; but if the joint line could be adequately reconstructed with augments and there was sufficient condylar bone to support this, then either cementless or cemented stems without a sleeve were used.

Five knees (1.57%) required re-revision surgery, at a mean of 35 months (median 18 months). Four of these were for infection; of which 3 required removal of the implants while the fourth was successfully treated with debridement, antibiotics, and implant retention (a DAIR procedure); 1 was revised for instability. No sleeve was revised for aseptic loosening. Twelve tibial sleeves (3.7%) showed radiographic subsidence >1 mm in subsequent radiographic follow up compared to immediate postoperative radiographs. All reached a position of stability without progressing further on subsequent radiographs and none required revision. Using re-revision as an endpoint, our implant survivorship was 99.1% at 3 years, 98.7% at 5 years and 97.8% at 10 years.

1.5. Overview of metaphyseal sleeves in the literature

There is growing body of evidence in the literature in support of using metaphyseal sleeves in rTKA. A number of recent systematic reviews have summarised the available evidence and reached similar conclusions albeit with the inevitable overlap of the studies included and the inherent limitations of level-IV evidence. Zanirato et al.²² reviewed 1079 rTKA (13 studies) using 1554 sleeves with mean follow up of 4 years. They reported implant and sleeves aseptic survival rate of 97.7 and 99.2%.

Bonanzinga et al.⁸ reported on 928 revisions (10 studies) with mean follow up of 45 months with 888 tibial sleeves and 525 femoral sleeves. There were 36 septic re-revisions of the prosthetic components (4%), of which 5 sleeves were found loose during septic re-revision; rate of septic loosening of the sleeves was 0.35%. Further, there were 27 aspetic re-revisions (3%), of which 10 sleeves were found loose during aseptic re-revision; rate of aseptic loosening of the sleeves was 0.7%. They also reported overall intraoperative fracture rate (3.1%).

Roach et al.²³ reported on 27 studies of metaphyseal sleeves and cones (12 sleeves and 15 cones). In total, there were 1617 sleeves implanted in 1133 rTKA. The overall rate of reoperation was 110/1133 (9.7%) and the total rate of aseptic loosening per sleeve was 13/1617 (0.8%). They also reported on 701 cones in 620 rTKA with overall reoperation rate of 116/620 (18.7%), and the overall rate of aseptic loosening per cone was 12/701 (1.7%).

The studies included in these systematic reviews were of varying sizes and duration of follow ups. Our series⁴ was not included in either of these reviews. Chalmers et al.⁵ reported on their tertiary experience in the Mayo Clinic of 280 patients using 393 metaphyseal sleeves (144 femoral, 249 tibial) between 2006 and 2014 with mean follow up of 3 years. Their sleeves were commonly cemented (55% femoral, 72% tibial). Using re-revision as an end point, they reported 5-year survivorship for aseptic loosening at 96% and 99.5% for femoral and tibial sleeves, respectively.

Despite the heterogeneity of the above studies in their indication for revisions, surgical techniques used or duration of follow up. There is clearly an emerging pattern with the success of metaphyseal sleeves in achieving osteointegration and excellent survivorship.

2. Conclusions

The use of metaphyseal sleeves in revision knee arthroplasty offers numerous advantages by addressing bone defects and efficient surgical preparation. In our experience, the use of sleeves simplifies the surgical procedure providing a stable tibial trial which optimises joint line positioning and gap balancing. Further, the close proximity of metaphyseal biological fixation to the joint line also has the added benefit of improved periarticular loading and subsequently bone preservation. The end result is a durable long-term biological fixation with a platform for varying degrees of constrained implants based on individual cases offering surgeons the versatility needed to address complex revision arthroplasty cases.