Does a Titanium-coated Polyethylene Press-fit Cup Give Reliable Midterm Results?

Background

Uncemented acetabular components have demonstrated low revision rates and high patient satisfaction but with concerns regarding increased costs compared with monoblock cups. Some newer lower-cost uncemented monoblock options have become available in the last decade, but limited data are available on their performance.

Questions/purposes

(1) Does an uncemented, titanium-backed all-polyethylene acetabular cup provide reliable fixation? (2) What is the frequency and what are the causes for revision with this cup?

Methods

Between 2004 and 2008, we elected to use an uncemented, titanium-backed all-polyethylene acetabular cup in older patients with limited physical demands. We performed 615 hip replacements in 550 patients with greater than 5 years of clinical and radiographic followup. When patients who were dead (80 hips in 75 patients), lost to followup (98 hips in 93 patients), or revised (three hips in three patients) were excluded, there were 434 hips in 379 patients for comparison of the postoperative and 5-year radiographs. Two observers not involved in the index surgical procedures (NH, HS) assessed radiographs for signs of migration or loosening. Some degree of early movement sometimes is seen before cup stabilization; however, to be conservative, we defined cups with greater than 3° of change of position (even if they subsequently stabilized) as potentially at risk and report them separately. Revision surgery, time from the index procedure, and the reason for revision were recorded from the New Zealand Joint Registry.

Results

By 5 years there was a median change in inclination of 2° (range, 0°–13°; 95% confidence interval [CI], 2.0–2.4; p < 0.001) and 2° of anteversion (range, 0°–11°; 95% CI, 2.0–2.4; p < 0.001). Although at last followup all cups appeared to have stabilized with no radiolucent lines or medial migration, 22% of the cups (94 of 434) had moved more than 3° and so were deemed to be potentially at risk. There were 11 revision procedures (of 429 hips; 2.5%) of which six were for recurrent dislocation, four for femoral fracture, and one for femoral loosening to give an overall all-cause revision rate for all components of 0.25 per 100 component years (95% CI, 0.13–0.43). No revisions were performed for acetabular loosening.

Conclusions

The short- to medium-term results of this all-polyethylene monoblock cup demonstrated a low frequency of revision. However, 94 cups were identified as potentially at risk based on movement of > 3° before apparent stabilization. Although those patients seem to be doing well enough now, the current duration of followup may not be sufficient to know that these cups will be durable, because other ongrowth designs have demonstrated a high frequency of late failure after apparent early success.

Level of Evidence

Level IV, therapeutic study.     

Dual mobility acetabular component in revision total hip arthroplasty for persistent dislocation: no dislocations in 50 hips after 1–5 years

Background

A dual mobility cup has the theoretic potential to improve stability in primary total hip arthroplasty (THA) and mid-term cohort results are favorable. We hypothesized that use of a new-generation dual mobility cup in revision arthroplasty prevents dislocation in patients with a history of recurrent dislocation of the THA.

Materials and methods

We performed a retrospective cohort study of patients receiving an isolated acetabular revision with a dual mobility cup for recurrent dislocation of the prosthesis with a minimum follow-up of 1 year. Kaplan–Meier survival analyses were performed with dislocation as a primary endpoint and re-revision for any reason as a secondary endpoint.

Results

Forty-nine consecutive patients (50 hips) were included; none of the patients was lost to follow-up. The median follow-up was 29 months (range 12–66 months). Two patients died from unrelated causes. Survival after 56 months was 100 % based on dislocation and 93 % (95 % CI 79–98 %) based on re-revision for any reason. Radiologic analysis revealed no osteolysis or radiolucent lines around the acetabular component during the follow-up period.

Conclusion

The dual mobility cup is an efficient solution for instability of THA with a favorable implant survival at 56 months.

Level of evidence

Level 4, retrospective case series.     

Long-term results of cementless femoral reconstruction following intertrochanteric osteotomy

Purpose

The objective of this retrospective cohort study was to assess the long-term outcome of cementless femoral reconstruction in patients with previous intertrochanteric osteotomy (ITO).

Methods

We evaluated the clinical and radiographic results of a consecutive series of 45 patients (48 hips, mean age 50 years) who had undergone conversion hip replacement following ITO with a cementless, grit-blasted, double-tapered femoral component. Clinical outcome was determined using the Harris hip score. Stem survival for different end points was assessed using Kaplan-Meier survivorship analysis.

Results

At a mean follow-up of 20 (range, 16–24) years, 11 patients (12 hips) had died, and no patient was lost to follow-up. Six patients (six hips) underwent femoral revision, two for infection, three for aseptic loosening and one for periprosthetic fracture. Mean Harris hip score at final follow-up was 78 points (range, 23–100 points). Stem survival for all revisions was 89% (95%CI, 75–95) at 20 years, and survival for aseptic loosening was 93% (95%CI, 80–98).

Conclusions

The long-term results with this type of cementless femoral component in patients with previous intertrochanteric osteotomy are encouraging and compare well to those achieved in patients with normal femoral anatomy.     

Poorer survival after a primary implant during revision total knee arthroplasty

Purpose

Revision total knee arthroplasty (rTKA) is a complex procedure. Depending on the degree of ligament and bone damage, either primary or revision implants are used. The purpose of this study was to compare survival rates of primary implants with revision implants when used during rTKA.

Methods

A retrospective comparative study was conducted between 1998 and 2009 during which 69 rTKAs were performed on 65 patients. Most common indications for revision were infection (30 %), aseptic loosening (25 %) and wear/osteolysis (25 %). During rTKA, a primary implant was used in nine knees and a revision implant in 60.

Results

Survival of primary implants was 100 % at one year, 73 % [95 % confidence interval (CI) 41–100] at two years and 44 % (95 % CI 7–81) at five years. Survival of revision implants was 95 % (95 % CI 89–100) at one year, 92 % (95 % CI 84–99) at two years and 92 % (95 % CI 84–99) at five years. Primary implants had a significantly worse survival rate than revision implants when implanted during rTKA [P = 0.039 (hazard ratio = 4.56, 95 % CI 1.08–19.27)].

Conclusions

Based on these results, it has to be considered whether primary implants are even an option during rTKA.     

Outcomes of dual-mobility acetabular cup for instability in primary and revision total hip arthroplasty

Background

The concept of a dual-mobility hip socket involves the standard femoral head component encased in a larger polyethylene liner, which in turn articulates inside a metal shell implanted in the native acetabulum. The aim of this study was to assess outcomes from using a Serf Novae^® Dual Mobility Acetabular cup (Orthodynamics Ltd, Gloucestershire, UK) to address the problem of instability in primary and revision total hip arthroplasty (THA).

Materials and methods

A retrospective review was carried out of all hip arthroplasties performed in a District General Hospital utilising the dual-mobility socket from January 2007 to December 2012. Clinical and radiological outcomes were analysed for 44 hips in 41 patients, comprising 20 primary and 24 revision THA. The average age of the study group was 70.8 years (range 56–84 years) for primary and 76.4 years (range 56–89 years) for revision arthroplasty. Among the primary THA, always performed for hip osteoarthritis or in presence of osteoarthritic changes, the reasons to choose a dual mobility cup were central nervous system problems such as Parkinson’s disease, stroke, dementia (10), hip fracture (5), failed hip fracture fixation (2), severe fixed hip deformity (2) and diffuse peripheral neuropathy (1). The indications for revisions were recurrent dislocation (17), aseptic loosening with abductor deficiency (4), failed hemiarthroplasty with abductor deficiency (2) and neglected dislocation (1).

Results

At a mean follow-up of 22 months (range 6–63 months), none of the hips had any dislocation, instability or infection and no further surgical intervention was required. Radiological assessment showed that one uncemented socket in a revision arthroplasty performed for recurrent dislocation had changed position, but was stable in the new position. The patient did not have complications from this and did not need any surgical intervention.

Conclusions

Even though postoperative hip stability depends on several factors other than design-related ones, our study shows promising early results for reducing the risk of instability in this challenging group of patients undergoing primary and revision hip arthroplasty.

Level of evidence

IV.     

Total hip arthroplasty with acetabular reconstruction using a bulk autograft for patients with developmental dysplasia of the hip results in high loosening rates at mid-term follow-up

Purpose

Managing a deficient acetabulum in patients with developmental dysplasia of the hip (DDH) can be challenging. The purpose of the study was to determine the mid-term results of total hip arthroplasty (THA) using a bulk structural autograft for reconstruction of the acetabular roof in patients with DDH.

Methods

Between 1982 and 1999, 112 patients underwent THA with acetabular roof-plasty using a bulk structural autograft for secondary osteoarthritis related to DDH. A total of 106 patients (115 hips) met inclusion criteria and were followed for an average of 11.6 years (seven to 24 years). The mean age was 52.5 years at the index operation. Clinical and radiological evaluations were performed according to the methods of Merle d’Aubigné and Postel, Johnston et al. and DeLee and Charnley.

Results

The overall Merle d’Aubigné hip score significantly improved (3.7 vs 10.4, p < 0.01). The limb length discrepancy decreased from 30 to 6 mm (p < 0.01). The average distance that the hip centre was distalised was 22.3 mm (0–56 mm). However, radiolucent lines were observed in 27 % of patients at final follow-up, and the overall rate of revision for aseptic loosening was 16 %. Further, Kaplan-Meier survivorship curves predicted a rapid increase in the failure rate at 15 years.

Conclusions

The mid-term functional outcome of THA with an acetabular roof-plasty using a bulk autograft is satisfactory; however, the long-term results are questionable.     

Recurrence of Dislocation Following Total Hip Arthroplasty Revision Using Dual Mobility Cups Was Rare in 180 Hips Followed Over 7?Years

Background

Dual mobility (DM) cups of mobile polyethylene were introduced to prevent total hip arthroplasty (THA) dislocation, but no large series with this design to treat recurrent instability have been reported.

Purpose

Our retrospective investigation ascertained the efficiency of DM cups in correction of recurrent dislocation and assessed any adverse effects.

Methods

One hundred eighty THAs with recurrent instability were revised to DM cups in 180 patients (mean age, 67.4 ± 11.7 years; range, 19 to 92 years). Thirty-one patients (17.2%) underwent at least one earlier THA revision, and 15 (10.3%) incurred non-union of the greater trochanter. Of the initial group in 2009, 145 patients had completed evaluations which included assessment of the Harris Hip Score and a radiographic assessment at a mean follow-up of 7.7 ± 2.2 years (range, 4 to 14 years). The rate of survival was calculated considering any reason for revision as failure.

Results

At follow-up, Harris hip score was 83.9 ± 16.1 (range, 21 to 100). Dislocation of the large articulation occurred in seven hips (4.8%), and only two recurred (1.4%) (one requiring additional revision). In addition, two intra-prosthetic dislocations of the small articulation (1.4%) were observed and needed revision surgery. The large number of earlier surgeries and non-union of the greater trochanter were related to recurrent instability. Two cups (1.4%) showed signs of definite loosening; six (4.1%) presented signs of possible loosening. Twenty-nine hips manifested femoral or acetabular osteolysis (20%), but only three were severe. Eight-year survival rate considering revision for any reason was 92.6% (95% CI, 85.5–96.4%).

Conclusions

This series indicates that DM cups are a viable option to treat recurrent THA instability. Their design provides a low risk of recurrent instability without increasing mechanical complications.     

Satisfying Outcomes Scores and Survivorship Achieved With Impaction Grafting for Revision THA in Young Patients

Background

The increasing number of total hip arthroplasties (THAs) performed in younger patients will inevitably generate larger numbers of revision procedures for this specific group of patients. Unfortunately, no satisfying revision method with acceptable survivorship 10 years after revision has been described for these patients so far.

Questions/purposes

The purposes of this study were to (1) analyze the clinical outcome; (2) complication rate; (3) survivorship; and (4) radiographic outcome of cemented revision THA performed with impaction bone grafting (IBG) on both the acetabular and femoral sides in one surgery in patients younger than 55 years old.

Methods

During the period 1991 to 2007, 86 complete THA revisions were performed at our institution in patients younger than 55 years. In 34 of these 86 revisions (40%), IBG was used on both the acetabular and femoral sides in 33 patients. Mean patient age at revision surgery was 46.4 years (SD 7.6). No patient was lost to followup, but three patients died during followup. None of the deaths were related to the revision surgery. The mean followup for the surviving hips was 11.7 years (SD 4.6). We also analyzed complication rate.

Results

The mean Harris hip score improved from 55 (SD 18) preoperatively to 80 points (SD 16) at latest followup (p = 0.009). Six hips underwent a rerevision (18%): in four patients, both components were rerevised; and in two hips, only the cup was revised. Patient 10-year survival rate with the endpoint of rerevision for any component for any reason was 87% (95% confidence interval [CI], 67%–95%) and with the endpoint of rerevision for aseptic loosening, the survival rate was 97% (95% CI, 80%–100%). In total six cups were considered radiographically loose, of which four were rerevised. Three stems were radiographically loose, of which none was rerevised.

Conclusions

IBG is a valuable biological revision technique that may restore bone stock in younger patients. Bone stock reconstruction is important, because these patients likely will outlive their revision implants. Bone reconstruction with impaction grafting may facilitate future revisions.

Level of Evidence

Level IV, therapeutic study.     

10-year results of the uncemented Allofit press-fit cup in young patients: 121 hips followed for 10–12 years

Background and purpose

Uncemented acetabular components in primary total hip arthroplasty (THA) are commonly used today, but few studies have evaluated their survival into the second decade in young and active patients. We report on a minimum 10-year follow-up of an uncemented press-fit acetabular component that is still in clinical use.

Methods

We examined the clinical and radiographic results of our first 121 consecutive cementless THAs using a cementless, grit-blasted, non-porous, titanium alloy press-fit cup (Allofit; Zimmer Inc., Warsaw, IN) without additional screw fixation in 116 patients. Mean age at surgery was 51 (21–60) years. Mean time of follow-up evaluation was 11 (10–12) years.

Results

At final follow-up, 8 patients had died (8 hips), and 1 patient (1 hip) was lost to follow-up. 3 hips in 3 patients had undergone acetabular revision, 2 for deep infection and 1 for aseptic acetabular loosening. There were no impending revisions at the most recent follow-up. We did not detect periacetabular osteolysis or loosening on plain radiographs in those hips that were evaluated radiographically (n = 90; 83% of the hips available at a minimum of 10 years). Kaplan-Meier survival analysis using revision of the acetabular component for any reason (including isolated inlay revisions) as endpoint estimated the 11-year survival rate at 98% (95% CI: 92–99).

Interpretation

Uncemented acetabular fixation using the Allofit press-fit cup without additional screws was excellent into early in the second decade in this young and active patient cohort. The rate of complications related to the liner and to osteolysis was low.Uncemented acetabular components are widely used all over the world. A variety of these components have been associated with excellent short- to medium-term clinical and radiographic outcomes (Hallan et al. 2010, Howard et al. 2011). During the second decade of use, a number of cementless cup designs have shown durable fixation, but problems related to wear and osteolysis often compromise the results, and the surgeon can face serious problems in revision surgery because of extensive bone loss. This is a particular problem with young and active patients (Kim et al. 2012). Currently, there are few reports on the survival of contemporary uncemented cups that are still in clinical use in young patient cohorts with a minimum of 10 years of follow-up (Akbar et al. 2009, Kim et al. 2012), despite being used frequently in this group of patients.We evaluated the ten- or more-year results of an independent series of the non-porous, uncemented, press-fit Allofit cup in young patients (≤ 60 years old) implanted without any additional fixation (screws) and compared the results with those reported in the literature.     

Ten year results of the collum femoris preserving total hip replacement: a prospective cohort study of seventy five patients

Purpose

The collum femoris preserving (CFP) uncemented prosthesis has a bone-preserving, high subcapital neck resection and a short anatomical stem. The ideal arthroplasty option in the younger, active patient is a subject of some debate. We evaluated midterm outcomes of the CFP in this patient population.

Methods

A prospective, consecutive cohort of 75 CFP total hip replacement (THR) patients with a mean age of 52 years was followed for a mean of 9.3 years. Patients were assessed using the Harris Hip Score (HHS). Pain was assessed using a visual analogue scale (VAS) and activity levels using the University of California, Los Angeles (UCLA) score. Radiographs were evaluated for evidence of loosening. Survivorship was calculated with an endpoint of revision for aseptic loosening or radiographic evidence of loosening.

Results

Mean HHS improved from a mean of 50 pre-operatively to 91 (p < 0.001) postoperatively. Mean pain score was 1, mean patient satisfaction was 9 and mean UCLA score was 6. Two acetabular components were revised for aseptic loosening; no stem required revision. Radiographically, no cases had evidence of loosening. Survivorship was 96.8 % for the acetabular component and 100 % for the stem at ten years. Three patients died from unrelated causes, and five were lost to follow-up.

Conclusions

Bone-preserving hip replacement has increased in popularity as hip replacement in younger and more active individuals increases. The CFP prosthesis has excellent midterm clinical function and survival and provides high levels of satisfaction in young patients.     

Acetabular rim lesions: arthroscopic assessment and clinical relevance

Purpose

The purpose of this study was to investigate whether acetabular morphology may influence both pathogenesis and prognosis of the acetabular rim lesions and to propose a new system to classify labral tears.

Methods

We assessed radiographic and arthroscopic findings in 81 patients (40 male and 41 female patients, 86 hips) aged from 16 to 74 years (median, 31 years) who underwent hip arthroscopy.

Results

Acetabular rim lesions were associated with four different hip morphologies. Eleven (32 %) of 34 patients with severe rim lesions underwent hip arthroplasty for progressive symptoms, whereas no patient with early rim lesion reported significant progression of symptoms. The strategy of treatment was changed in 33 % of the patients undergoing arthroscopy before undertaking peri-acetabular osteotomy.

Conclusions

Hip arthroscopy avoids more invasive procedures in patients with early acetabular rim lesions.     

Long term results after surgical management of posterior wall acetabular fractures

Background

Posterior wall fractures are the most common of all acetabular fractures, and there is universal consensus that displaced fractures are best treated with anatomical reduction and stable internal fixation. Though early and mid term results for such studies are available, few shed light on long term results. This study was performed to evaluate long term functional and radiological outcomes in patients with posterior wall acetabular fractures and to determine factors that may contribute adversely to a satisfactory final outcome.

Materials and methods

We retrospectively analysed the hospital records for patients who underwent open reduction and internal fixation (ORIF) for posterior wall acetabular fractures. Twenty-five patients (20 men, five women), including one with bilateral posterior wall fracture, with a mean age of 41.28 ± 7.16 years (range 25–60 years) and a mean follow-up of 12.92 ± 6.36 years (range 5–22 years) who met the inclusion criteria formed the study cohort. Matta’s criteria were used to grade postoperative reduction and final radiological outcome. Functional outcome at final follow-up was assessed according to d’Aubigné and Postel score.

Results

Anatomic reduction was achieved in 22 hips, imperfect in four and poor in none. Radiological outcome at final follow-up revealed excellent results in ten hips, good in eight, fair in five and poor in three. The final d’Aubigné and Postel scores were excellent in 14 hips, good in six and fair and poor in three each. Patients with anatomical reduction had a favourable functional and radiological long term outcome. However, the presence of associated injuries in lower limbs and a body mass index (BMI) >25 adversely affected the final functional outcome. Osteonecrosis was seen in three patients, heterotopic ossification in two and Morel Lavallee lesion in one. One patient had postoperative sciatic nerve palsy, which recovered 6 weeks after surgery.

Conclusion

Anatomic postoperative reduction leads to optimal functional and radiological outcome on long term follow-up; however, the presence of associated lower-limb injuries and BMI >25 adversely affects a satisfactory final outcome in patients with posterior wall acetabular fractures.

Level of evidence

(Level 4) Retrospective case series.