Are Hooded, Crosslinked Polyethylene Liners Associated with a Reduced Risk of Revision After THA?

BACKGROUND: Hooded acetabular liners and head sizes ≥ 32 mm have both shown to have a beneficial effect on the revision rate for dislocation in THA. Experience with noncrosslinked polyethylene (nonXLPE) raised concerns regarding the risk of impingement damage, loosening, and osteolysis with hooded liners; however, the evidence for this in crosslinked polyethylene (XLPE) is inconclusive. The interaction between different femoral head sizes and hooded liners is not well understood, and it is unclear whether hooded XLPE liners have a beneficial effect on overall long-term survivorship. QUESTIONS/PURPOSES: We analyzed a large national joint registry to ask: (1) Is the use of hooded XLPE liners associated with a reduced revision rate for dislocation compared with nonhooded liners? (2) Is there a difference in the revision rate for aseptic loosening/osteolysis? (3) Is head size associated with any difference in the revision rate between hooded and nonhooded liners? METHODS: The Australian Orthopaedic Association National Joint Replacement Registry longitudinally maintains data on all primary and revision joint arthroplasties with nearly 100% capture. We analyzed all conventional primary THAs performed from registry inception in September 1999 until December 31, 2016 in patients with a diagnosis of osteoarthritis who had nonhooded or hooded XLPE bearings in a cementless acetabular shell. The study group included 192,659 THA procedures with XLPE liners, of which 67,904 were nonhooded and 124,755 were hooded. The mean age of patients receiving nonhooded liners was 70 years (range, 11-100 years); 44% were males. This was similar to the patients with hooded liners, who had a mean age of 70 years (range, 16-100 years); 45% were males. The main outcome measure was the cumulative percent revision at 15 years of the THA using Kaplan-Meier estimates of survivorship. We examined reasons for revision and and performed multivariable analysis to control for the confounding factors of three head size groups (< 32mm, 32mm, and > 32mm) and for the method of femoral fixation. RESULTS: There was a higher revision rate for dislocation for patients with nonhooded liners at all times to 15 years (HR, 1.31; 95% CI, 1.17-1.47; p < 0.001). There was a higher revision rate for the diagnosis of aseptic loosening/osteolysis with patients with nonhooded liners compared with hooded liners (HR, 1.19; 95% CI, 1.05-1.34; p = 0.006). Head sizes of 32 mm or larger were independently associated with a lower comparative revision rate between hooded and nonhooded liners, but this was not apparent for head sizes smaller than 32 mm. It appeared that the main driver of the finding in larger heads was a reduced dislocation risk with hooded liners for 32 mm heads (HR, 1.50; 95% CI, 1.23-1.80; p < 0.001) and for heads larger than 32 mm (HR, 1.50; 95% CI, 1.20-1.89; p < 0.001). CONCLUSIONS: Prior research has suggested that hooded acetabular liners may be associated with impingement, loosening, and osteolysis; however, in this large, registry-based report we found that XLPE hooded liners are not associated with an increased revision rate for aseptic loosening/osteolysis. Although there are many potential confounding variables in this registry analysis, if anything, surgeons using larger femoral heads and hooded liners likely did so in patients with a higher perceived dislocation risk. Patients with larger heads and XLPE hooded liners were, however, less likely to experience revision for dislocation. These liners therefore appear reasonable to use in primary THA at the surgeon's discretion. LEVEL OF EVIDENCE: Level III, therapeutic study.

Outcome following total knee replacement in patients with a previous patellectomy.

Although patellectomy is a rarely performed surgical procedure, patients may still progress to develop osteoarthritis of the tibiofemoral compartments leading to total knee replacement surgery. Due to the mechanical disadvantage of a previous patellectomy, it has previously been suggested that a prosthesis with more constraint should be used, however, there are conflicting reports in the literature. We aimed to assess the effects of stability following total knee replacement in patellectomised knee with revision as a primary endpoint. We reviewed the outcome of 25 total knee replacements in our institution in patients with a previous patellectomy. Ten were posterior stabilised and 15 minimally stabilised (including those with a 'deep dish'). Five of the patients in the minimally stabilised group underwent revision surgery, and 3 of these were early revision due to instability. None of the patients in the posterior stabilised group underwent revision. We conclude that when a total knee replacement is performed in a patient with a previous patellectomy a posterior stabilised implant should be used.

Staged venous thromboemolic events prophylaxis with low-molecular-weight heparin followed by aspirin is safe and effective after arthroplasty.

BACKGROUND: The rate of fatal pulmonary embolism (PE) following hip and knee arthroplasty has remained unchanged despite the use of low-molecular-weight heparin (LMWH) and oral antithrombotic agents. Concerns regarding bleeding and wound complications resulted in the introduction of a staged chemoprophylaxis protocol at our institution in 2002. We hypothesized that staged chemoprophylaxis using LMWH in hospital followed by aspirin after discharge was safe and effective for the prevention of venous thromboembolic events (VTE). METHODS: Data were retrospectively collected on all patients undergoing hip and knee arthroplasty between 2002 and 2012. For VTE prophylaxis, LMWH was administered to all patients following surgery until discharge. Aspirin was prescribed from discharge until 6 weeks following surgery. Complications were recorded in a database. Patients suspected of having a VTE were investigated with bilateral lower limb duplex ultrasound and computerized tomography-pulmonary angiogram. RESULTS: The 11-year results of this protocol used in 9035 patients with a mean age 62 years (range 20-95) and follow-up at 6 weeks demonstrate an overall symptomatic VTE rate of 2.55% and overall PE rate of 1.28%. The overall fatal PE rate is 0.03% (unicompartmental knee arthroplasty 0.07-0.96%, total knee arthroplasty 0.19% and total hip arthroplasty 0%) and the all-cause mortality is 0.07%. The wound complication rate is low. CONCLUSION: Staged chemoprophylaxis using LMWH followed by aspirin is a safe and effective thromboprophylactic regime that is associated with a very low rate of fatal PE and all-cause mortality.

Sciatic Nerve Palsy following Total Hip Replacement via Direct Anterior Approach after Recommencement of Warfarin for Prophylaxis in Atrial Fibrillation.

The occurrence of sciatic nerve palsy following posterior and anterolateral approaches to the hip has been well documented and is about 1-2%. To our knowledge, however, there are no reports of sciatic nerve palsy occurring secondary to the anterior approach to the hip for arthroplasty. We describe a case of sciatic nerve palsy secondary to haematoma formation following total hip replacement through the anterior approach. The recommencement of warfarin for prophylaxis against atrial fibrillation is thought to have been a contributing factor. Full recovery is rare following delayed diagnosis and early recognition of the signs of pain, parasthesia, and gradual loss of dorsiflexion and prompt drainage may reverse the condition. We advise caution with restarting warfarin following total hip arthroplasty.

Extended trochanteric osteotomy followed by cemented impaction allografting in revision hip arthroplasty.

The aim of this study is to present the medium- to long-term results of all cases of femoral impaction allografting revision at our institution that required an extended trochanteric osteotomy (ETO) at the time of surgery. Eighteen patients with a mean age of 60 years were evaluated. Indication for revision was aseptic loosening in all cases. The mean follow-up was 123 months (51-170). Charnley-D'Aubigné-Postel scores, stem length, ETO length, ETO healing, and complications were recorded. No patient was lost to follow-up. Signs of clinical healing were noted within the first 6 postoperative months. The difference between the preoperative and postoperative clinical scores was statistically significant. No nonunion of the ETO was observed in any case. These results give support to the combined use of these techniques.

Posterior longitudinal split osteotomy for femoral component extraction in revision total hip arthroplasty.

We present a technique of single posterior longitudinal split osteotomy. This technique allows the expansion of the proximal femur and easier extraction of uncemented femoral components. Since 1998 we have performed this osteotomy in 12 revision total hip arthroplasties in 11 patients who had either stable fibrous ingrowth or a small amount of bony ingrowth. All were revised to a cemented Exeter stem (Stryker Benoist Gerard, Caen, France). No patient required conversion from a longitudinal split to an extended trochanteric osteotomy. At mean follow-up of 48 months, there were significant improvements in both pain and function. There were no complications due to this technique. Mean in-cement taper engagement (subsidence) was 1.1 mm (range, 0-2 mm). Femoral impaction grafting did not adversely affect the cement mantle or increase in-cement taper engagement. With appropriate patient selection, this is a simple, reliable, and extensile technique to assist in the extraction of uncemented ongrowth femoral components whether hydroxyapatite-coated or not.