A collarless cobalt-chrome femoral component in uncemented total hip arthroplasty. Five- to eight-year follow-up

Mid-Term Follow-Up Results After Hemiarthroplasty Using Long Femoral Stem Prosthesis (Peerless-160) for Intertrochanteric Fractures in Octogenarians

Purpose

To analyze the clinical effect and imaging data of cementless bipolar hemiarthroplasty employing a long femoral stem (peerless-160) and 2 reconstructed femoral titanium wires to repair intertrochanteric fractures among the octogenarians.

Methods

Between June 2014 and August 2016, 58 octogenarians with femoral intertrochanteric fractures underwent the long femoral stem (peerless-160) cementless bipolar hemiarthroplasty by the same surgeon. We assessed clinical and radiological outcomes such as operative time, bleeding volume, blood transfusion volume, length of hospital stay, full weight-bearing walking time, walking ability calculated by Koval classification and Harris Hip Score (HHS), including fracture healing and greater trochanter fragments subsidence.

Result

The surgery was successfully performed in all patients. The average operation time was 72.8 ± 13.2 min, the average blood loss during surgery was 225.0 ± 91.4 mL, 200 mL of blood was transfused, the mean duration of hospitalization was 11.9 ± 4.0 days, the mean time of full weight bearing was 12.5 ± 3.8 days. Patients were followed up for 24-68 months, averagely 49.4 ± 10.3 months. During follow-up, 4 (6.9%) patients died, and 1 (1.7%) was completely lost to ask about the recent situation. The average Harris Hip Score at the last follow-up was 87.8 ± 6.1, most of the patients recovered walking ability, under radiological examination, the prosthesis showed no signs of loosening. All trochanteric fractures gradually healed, the clinical and radiographic signs of healing occurred at average of 4.0 ± 1.1 months postoperatively.

Conclusion

For osteoporotic unstable intertrochanteric fractures in octogenarians, this study confirmed that the Cementless Bipolar Hemiarthroplasty Using a Long Femoral stem (peerless-160) with double cross binding technique is a satisfactory and safe choice for the octogenarians.

Total Hip Arthroplasty Performed with a Novel Design Type 1 Femoral Stem: A Retrospective Minimum 5-Year Follow-up Study

Background

The Bencox M stem is a mid-short type 1 stem with additional unique design features. It has a reduced stem length and a lateral shoulder to facilitate minimally invasive surgery, as well as an angular lateral shoulder and a trapezoidal neck to minimize stem-liner impingement. There have been many mid-term reports on type 1 stems, but no results have been reported so far on this novel design type 1 femoral stem. This study presents the clinical and radiological outcomes of total hip arthroplasty performed with the M stem after a minimum 5-year follow-up.

Methods

From July 2014 to February 2015, 125 primary total hip arthroplasties using the M cementless femoral stem were performed on 112 patients in our hospital. Among them, 94 patients (106 hips) were eligible for the study and were followed up for more than 5 years. Our primary outcome was clinical results, which were evaluated by the Harris Hip Score (HHS), thigh pain, noise, and other complications. Secondary outcome was radiological outcomes. Seventy-seven hips were evaluated radiologically with attention to implant fixation, migration, loosening of component, degree of stress shielding, radiolucent lines, focal osteolysis, heterotopic ossification, and the evidence of impingement between the stem and liner.

Results

The average HHS improved from 54.6 points (range, 24–67 points) to 96.8 points (range, 91–100 points) at the latest follow-up. Three hips (2.8%) had intermittent thigh pain, which was tolerable without medication. Five hips (4.7%) had ceramic-related noise. There were no other complications such as infection, nerve injury, dislocation, or revision. All implants showed radiographic evidence of stable fixation by bone ingrowth without migration. Fifty-seven hips (74%) showed mild femoral stress shielding. Distal cortical hypertrophy was detected in 7 hips (9%), and heterotopic ossification was observed in 17 hips (22%). No implant demonstrated focal osteolysis and notching of the femoral neck or shoulder on radiographs.

Conclusions

The minimum 5-year results of total hip arthroplasty performed with the M cementless femoral stem were encouraging clinically and radiologically. A long-term follow-up will be necessary to evaluate its longevity.

Returning to Yoga Practice and Teaching After Total Hip Arthroplasty

Patients who practice yoga are motivated to return to practice after total hip arthroplasty (THA). With case reports of dislocations during yoga, the safety of such a return is unclear. The purpose of this study is to examine the timing and feasibility of a return in a subset of highly experienced and motivated patients. Between 2010 and 2019, a total of 19 THA’s performed in 14 patients who self-identified as yoga instructors were retrospectively reviewed. Patients who practiced yoga but were not teachers were excluded from this series. The primary outcome measures were the ability to return to yoga, to resume teaching, and fluency with 14 classic poses. Secondary outcomes measured were patient-reported Hip Disability and Osteoarthritis Outcome Score (HOOS, Jr.), complications, and radiographic position of the implants. After surgery, all patients returned to practicing and teaching yoga, and the mean time to each was 2 months. All patients were able to perform all 14 classic poses. At a mean follow-up of 5 years (SD ± 4), there were no complications, and the mean HOOS, JR score was 92 points (SD ± 15). This study demonstrates that a return to yoga in an experienced population is not only possible but also safe after a direct anterior THA. Limitations in performing the poses should be understood, and appropriate modifications should be incorporated when needed.

Second-generation uncemented total hip arthroplasty: a minimum 20-year follow-up

Aims

We present the clinical and radiological results at a minimum follow-up of 20 years using a second-generation uncemented total hip arthroplasty (THA). These results are compared to our previously published results using a first-generation hip arthroplasty followed for 20 years.

Methods

A total of 62 uncemented THAs in 60 patients were performed between 1993 and 1994. The titanium femoral component used in all cases was a Taperloc with a reduced distal stem. The acetabular component was a fully porous coated threaded hemispheric titanium shell (T-Tap ST). The outcome of every femoral and acetabular component with regard to retention or revision was determined for all 62 THAs. Complete clinical follow-up at a minimum of 20 years was obtained on every living patient. Radiological follow-up was obtained on all but one.

Results

Two femoral components (3.2%) required revision. One stem was revised secondary to a periprosthetic fracture one year postoperatively and one was revised for late sepsis. No femoral component was revised for aseptic loosening. Six acetabular components had required revision, five for aseptic loosening. One additional acetabular component was revised for sepsis. Radiologically, all femoral components remained well fixed. One acetabular was judged loose by radiological criteria. The mean Harris Hip Score improved from 46 points (30 to 67) preoperatively to 89 points (78 to 100) at final follow-up. With revision for aseptic loosening as the endpoint, survival of the acetabular component was 95% (95% confidence interval (CI) 90 to 98) at 25 years. Femoral component survival was 100%.

Conclusion

The most significant finding of this report was the low prevalence of aseptic loosening and revision of the femoral component at a mean follow-up of 22 years. A second important finding was the survival of over 90% of the hemispheric threaded ring acetabular components. While these shells remain controversial, in this series they performed well.Cite this article: Bone Jt Open 2021;2(1):33-39.

Primary total hip arthroplasty using a short bone-conserving stem in young adult osteoporotic patients with Dorr type C femoral bone

BACKGROUND

Dorr type C femoral bone exhibits a wide, stovepipe-shaped femoral canal, and thin cortices in the proximal femur. Dorr C bone combined with severe osteoporosis is an important challenge in primary hip arthroplasty. In this study, we assessed the effects of short metaphyseal fitting cementless stems on preformatted primary total hip arthroplasties in young adult osteoporotic patients with this femoral presentation.

METHODS

A total of 42 hip arthroplasties were performed in 35 young patients (range 20 to 36 years) using a short Tri-lock bone preservation metaphyseal-fitting cementless femoral component between 2012 and 2017. The mean age at surgery of the 27 male (33 hips) and 8 female (9 hips) patients was 27.5 years (range 20.3 to 35.8 years). The mean body mass index (BMI) was 20.2 kg/m2 (range, 16.8-23.2 kg/m2). According to Dorr's criteria, all 42 femora were classified as type C bone and all femurs suffered from severe osteoporosis (Singh index ≤ 3).

RESULTS

The mean follow-up period was 5.5 years (range 3.0 to 8.0 years). The clinical and functional results improved for the Harris hip score, WOMAC, and UCLA activity scores. The Harris Hip score improved from 48.0 ± 8.0 (range 38.0 to 61.0) preoperatively to 87.0 ± 9.0 (range 77.0 to 92.0) at 12 months after surgery and 91.0 ± 8.0 (range 85.0 to 98.0) at final follow-up. The preoperative UCLA activity score was 3.0 ± 0.5 points (range, 1.0-4.0 points), which significantly improved to 7.5 ± 0.7 points (range 6.0 to 8.0 points) at the final follow-up. No patient exhibited thigh pain at the final follow-up. The mean stem-to-canal fill percentages were 97% ± 2.1% (anteroposterior view at midstem). For stem alignment, 40 hips (95.2%) of the femoral stem were positioned neutrally to 3° of varus with reference to the femoral shaft axis. The remaining two were positioned at 4° varus to 4° valgus. Radiographic evaluation showed good osteointegration of the implants in follow-up.

CONCLUSIONS

Based on the tapered-wedge design and proximal porous coating, the shortened tapered conventional stem can achieve reliable stability through neck filling and metaphyseal fixation, which does not depend on the isthmus hoop stress. This stem was suitable in severe osteoporotic patients with type C bones in young adults who presented with a correspondingly straightened femoral canal with a wide isthmus and thin cortex.

Initial Rotational Instability of the Tapered Wedge-Shaped Type Cementless Stem

Background

Because the tapered wedge-shaped type cementless stem has a small anteroposterior width and a low occupation rate in the medullary space, postoperative rotational instability and stem subsidence due to inadequate proximal fixation are concerns. The purpose of this study was to clarify the relationship between the rotational instability of the tapered wedge-shaped type cementless stem and femoral canal shape.

Methods

A total of 61 primary total hip arthroplasties with the tapered wedge-shaped type cementless stem Accolade® TMZF (11 males, 50 females; mean age 60 years) from January 2012 to June 2015 who underwent computed tomography before surgery and within 4 weeks and 1 year after surgery were evaluated. The preoperative femoral neck anteversion angle, preoperative femoral canal flair index, the degree of postoperative stem subsidence within 1 year after operation, and the degree of rotational change in the stem setting angle within 1 year after operation were investigated.

Results

The mean preoperative femoral neck anteversion angle was 32.2° ± 17.8° (0°–69°), and the mean preoperative canal flair index was 3.68 ± 0.58 (2.44–5.55). There were no stem subsidence cases within 1 year after operation. The mean degree of rotational change in the stem from immediately to 1 year after surgery was −0.4° ± 1.7° (−3°–3°). There was no significant correlation between the canal flair index and the rotational change in the stem. In addition, the mean difference between the preoperative femoral neck anteversion angle and the stem rotational angle immediately after surgery was only 1.3° ± 5.3° (−29°–15°).

Conclusions

In all cases, including stove-pipe cases, the degree of rotational change in the Accolade® TMZF stem from immediately to 1 year after surgery was within 3°. In other words, regardless of femoral canal shape, the tapered wedge-shaped type cementless stem has little initial rotational instability.

Primary total hip arthroplasty using an uncemented Wagner SL stem in elderly patients with Dorr type C femoral bone

Background

The purpose of this study was to review retrospectively the primary total hip arthroplasties operated upon with the cementless Wagner Self-Locking stem in patients with type C femoral bone.

Methods

Twenty-eight total hip arthroplasties were performed in 25 patients aged ≥ 60 years using a cementless Wagner Self-Locking femoral component between 2006 and 2011. According to Dorr’s criteria, all 28 femora were classified as type C bone. All patients were treated with THA using a cementless Wagner cone prosthesis. Clinical and radiologic evaluations were performed on all patients.

Results

Mean follow-up period was 125 ± 10.5 months (range 96 to 156 months). Average Harris hip score pre-operatively was 46 ± 9 (range 39 to 62) and at the last follow-up was 90 ± 9 (range 83 to 98). The stem to canal fill is calculated as percentages on the operative side at three distinct levels: just below the lesser trochanter, at midstem, and 1 cm above the tip of the component on anteroposterior radiograph. The mean proximal stem-to-canal fill percentages were 97% ± 2.1%, 95% ± 3.5%, and 88% ± 2.6%, respectively (anteroposterior view) and 92% ± 2.2%, 86% ± 1.9%, and 83% ± 2.5%, respectively (lateral view). Radiographic evaluation demonstrated good osteointegration of the implants in the follow-up.

Conclusions

Based on the long-straight cylindrical tapered stem design, the cementless Wagner SL stem can achieve reliable stability by close apposition of the stem and wide stovepipe femoral canal from metaphysis to diaphysis in type C bone.

Functional and radiological outcome of uncemented total hip arthroplasty in young adults - 5 year follow-upollow-up

Background

End stage arthritis in young patients requires surgical intervention. THA remains the treatment of choice for restoring function and activity in end stage hip arthritis. The medium term outcome of uncemented THA in Indian population is less studied. Hence this study was taken up with aim to study clinical and radiological outcome of uncemented THA in patients with age less than 40 years.

Methods

This study was conducted during January 2013 to December 2013. Overall 66 patients with 74 arthritic hips were operated by single surgeon (1st Author) with Uncemented THA. All patients were either unilateral or bilateral arthritis of hip less than 40 years of age. Patients were evaluated preoperatively and postoperatively. After discharge patients were followed up at regular intervals. Activity level and Harris Hip score was calculated. Radiological evaluation was done with anteroposterior and lateral X-rays.

Results

Total 50 patients (56 hips) followed up at five year follow-up. Clinical and radiological evaluation was done during follow-up. Most common etiology was avascular necrosis of hip (56.6%). None of the patients had any major complications. Mean Harris Hip score improved from 36 to 92. The activity level was assessed at five year follow-up with maximum patients in moderate manual labor category. Bony ingrowth with no evidence of loosening was seen consistently both on femoral and acetabular side in all patients on X-ray. No statistically significant association was found between initial alignment of the femoral component and clinical outcome.

Conclusion

Uncemented THA can be used in young patients with excellent to good functional and radiological outcome at midterm follow-up, high satisfaction rate and lower rate of complications.

Primary Total Hip Arthroplasty Using an Uncemented Wagner SL Stem in Elderly Patients With Dorr Type C Femoral Bone

The purpose of this study was to review retrospectively the primary total hip arthroplasties operated upon with the cementless Wagner self-locking stem in patients with Type C femoral bone. Twenty-five total hip arthroplasties were performed in 23 patients aged ≥60 years using a cementless Wagner self-locking femoral component between 2006 and 2011. According to Dorr's criteria, all 25 femora were classified as type C bone. Mean follow-up period was 62 months (range, 47–85 months). Average Harris Hip score preoperatively was 46 ± 9 (range, 39–62) and at the last follow-up was 90 ± 9 (range, 83–98). The mean proximal stem-to-canal fill percentage was 95% ± 3.5% (anteroposterior view) and 90% ± 2.8% (lateral view) and the mean distal canal fill was 93% ± 4.5% (anteroposterior) and 92% ± 3.9% (lateral). Radiographic evaluation demonstrated good osteointegration of the implants in follow-up. Based on the long-straight cylindrical tapered stem design, the cementless Wagner SL stem can achieve reliable stability by close apposition of stem and wide stovepipe femoral canal from metaphysis to diaphysis in Type C bone.

Comparison of an Uncemented Tapered Stem Design in Cobalt-Chrome vs Titanium at 15-Year Follow-Up

BACKGROUND

Cobalt-chromium (Co-Cr) and titanium (Ti) have been the most popular materials employed for cementless implants. The purpose of this study was to compare clinical and radiological results of a single stem design with both alloys at long-term follow-up.

METHODS

Two hundred consecutive uncemented stems implanted in 171 patients (100 Co-Cr and 100 Ti implants) between 1999 and 2002 were studied. Mean age of the patients was 60.9 years (range, 20-84). Clinical results were evaluated using the Harris hip score. The presence of thigh pain was also analyzed. Stem fixation was graded according to Engh criteria. Radiolucent lines, osteolysis, and stem subsidence were also analyzed.

RESULTS

At 15-year follow-up, no stems had been revised. Both groups showed similar clinical results with mean Harris hip score of 93.4 (Co-Cr) vs 93.9 (Ti). There was no difference in the rate of thigh pain (11 vs 8.3, respectively, P = .507). Radiolucent lines were more frequent in the Co-Cr group (63.6% vs 35.6%, P < .001).

CONCLUSION

Ti stems showed better osteointegration than Co-Cr stems, with a significantly lower incidence of radiolucent lines. However, this did not affect the clinical results or the appearance of thigh pain.

Clinical Performance, Patient Reported Outcome, and Radiological Results of a Short, Tapered, Porous, Proximally Coated Cementless Femoral Stem: Results up to Seven Years of Follow-Up

BACKGROUND

The primary aim of our study was to assess clinical performance, patient reported outcome and radiological results of cementless primary total hip arthroplasty using Tri-Lock Bone Preservation Stem.

METHODS

Between March 2010 and June 2012, 163 consecutive patients, were enrolled in the study. Patients were assessed clinically and radiographically prior to surgery as well as at 6, 12, 24 months and then at 5, 6, and 7 years postoperatively.

RESULTS

Using the Dorr classification, 39 patients (23.9%) were classified as Dorr A, 116 patients (71.2%) as Dorr B, and 8 patients (4.9%) as Dorr C. A total of 139 patients (85.3%) received a high offset, whereas 24 patients (14.7%) received a standard offset stem. Total Harris Hip Score of the patients increased from a mean of 27.29 (±4.6) preoperatively, upto 97.28 (±9.0) after 5 years. Mean preoperative Short Form-12 (SF-12) Physical Health Composite Scale score was 27.31 (±3.8). After 5 year was 55.3 (34-57). The mean preoperative SF-12 Mental Health Composite Scale score was 57.02 (±5.9). After 5 year was 59.3 (28.7-60.8). Only one patient underwent revision surgery for dislocation and revision of the head.

CONCLUSION

Tri-lock Bone Preservation Stem DePuy proved to be an easy-to-use device. Results obtained up to 7 years of FU show excellent clinical performance, as well as radiographic osseointegration, with no cases of aseptic loosening and no images of progressive radiolucent lines or periprosthetic osteolysis.

Outcomes using wedge stem with full hydroxiapatite coverage with a minimum of 5 years' follow-up

INTRODUCTION

Total Hip Arthroplsty (THA) using uncemented stems is a popular practice in the last decades. The implant survivorship is crtitical and a less than 10% revision at 10 years is been propesed for commercialization and use.

OBJECTIVE

To analyse the clinicoradiological results of an uncemented hydroxiapatite covered wedge stem with a 5 years minimum follow up.

MATERIAL AND METHODS

Prospective study, patients aged from 21-75years were included. All patients received an Element stem (Exactech) and uncemented cup with crosslink poly and 32 mm metal head, and posterior approach with piriformis retention was used. Scheduled clinical and radiographic evaluation at 3 weeks, 3-6 month, year and subsequent years using Harris Hip Score and Merle d'Aubigné Postel. Intraoperative and during follow up complications were recorded.

RESULTS

One hundred and fourteen total hip replacements in 104 patients: 54 females and 50 males (52%/48%). Follow-up of 5.7 years (range, 5-6.2years). Average age 56.8years (range, 42-75years). Clinical evaluation the Merle d'Aubigné score improved 6.8 points and from the initianl Harris Hip Score 47.3 to 93.1 points at last follow up. Radiographic evaluation shows osteointegration in all stems. And in 6 cases (5.3% at 3 months subsidence was detected, average 1.4 mm (range 0-2.6 mm) with no clinical manifestation, 3 cases of subsidence were associated to intraoperative fractures (1 greater trochanter and 2 in the calcar area, all resolved with wire cerclaje). Subjective evaluation: 86 cases (82.6%) excellent, 9 patients (8.6%) good, 6 cases (5.9%) satisfactory and 3 cases (2.9%) poor. All poor results linked to the intraoperative complications. No patient lost during follow up period. No femoral pain dislocation or aseptic or loosening detected. All implants were in situ at last follow up.

CONCLUSIONS

The radiological results confirm the benefits of this type of stem with good osteointegration. The clinical and subjective results are promising. With good surgical technical and without complications the risk of aseptic loosening should be absent or minimal.

Developmental hip dysplasia treated by total hip arthroplasty using a cementless Wagner cone stem in young adult patients with a small physique

BACKGROUND

Developmental hip dysplasia (DDH) may lead to severe acetabular and femoral abnormalities that can render total hip arthroplasty (THA) challenging, especially in DDH patients with a small physique. Most conventional cemented or cementless femoral components are often difficult to implant in the narrow femoral canal and require slight version correction during surgery. The aim of this study was to present the mid-term results of THA in the treatment of DDH patients with a small physique using a cementless Wagner cone prosthesis (Zimmer®, US).

METHODS

Between January 2006 and March 2010, we retrospectively reviewed 50 patients who were treated at our center. A total of 50 patients (52 hips; 45 women, five men; mean age 32.5 years; range 27 to 38 years) who underwent THA were observed. The mean femoral medullary canal dimension at the isthmus was 7.6 mm (range 6.0 to 8.7). According to the Crowe classification, 19 hips presented dysplasia of grade I, while 33 presented dysplasia of grade II. All patients were treated with THA using a cementless Wagner cone prosthesis. Clinical and radiologic evaluations were performed on all patients.

RESULTS

The mean duration of follow-up was 7.7 years (range 5.4 to 10.5). The Harris hip score (HHS) improved from 63 ± 9 (range 55 to 70) pre-operatively to 92 ± 8 (range 88 to 100) at the last follow-up. The HHS at the most recent follow-up was excellent in 66% of patients (34 hips), good in 26% (14 hips), fair in 6% (3 hips), and poor in 2% (1 hip). Radiographic evaluation demonstrated excellent osteointegration of the implants. Stem subsidence was present in three stems, and the range of stem subsidence was 2 mm in two stems (3.9%) and 3 mm in one stem (1.9%). Femoral osteolysis was observed in nine hips (18%) in the proximal zones, and no distal osteolysis was noted. Heterotopic ossification was observed in three hips (5.8%); of these, two were classified as Brooker's grade 1, and one was classified as Brooker's grade 2 at the most recent follow-up. None of the implants were revised.

CONCLUSIONS

Based on the tapered shape and free setting of anteversion, the Wagner cone femoral stem facilitates its implantation in dysplastic hips. Therefore, this series of short stems with a smaller diameter can ensure safe implantation in narrow medullary canals, especially in young DDH patients with a small physique.

TRIAL REGISTRATION

Registration Number: ChiCTR-ORC-17011181 . Reg Date: 2017-04-19 00:44:59 Retrospective registration.

New Approach and Stem Increased Femoral Revision Rate in Total Hip Arthroplasty

This study compared the femoral stem revision and loosening rates in primary total hip arthroplasty between 2 different approaches and stem designs. Recent reports comparing the direct anterior approach with either the posterior or lateral approach showed that patients undergoing the direct anterior approach have less pain and an accelerated functional recovery in the early postoperative period. After converting to an anterior approach, the authors observed an increased rate of femoral stem revision. From 2003 to 2009, a posterior or lateral approach was used to insert 514 stems of 2 designs. These cases included the use of an extensively coated cobalt-chrome stem (n=232) or a straight, dual-tapered, proximally porous-coated titanium stem (n=282). In the following years, from 2009 to 2012, 594 short, proximally coated, titanium tapered-wedge stems were inserted through a direct anterior approach. The revision rates of femoral stems inserted through a posterior approach or a lateral approach were compared with those inserted via a direct anterior approach. No stem revisions occurred in the posterior approach group or the lateral approach group, and 5 stems were revised in the anterior approach group for periprosthetic fracture or aseptic loosening (0.8%). Significantly more stem revisions occurred after the use of the new stem design and a direct anterior approach (P=.04).

Long-term results of uncemented total hip arthroplasty with the Taperloc femoral component in patients with Dorr type C proximal femoral morphology

Aims

To investigate the longevity of uncemented fixation of a femoral component in total hip arthroplasty (THA) in patients with Dorr type C proximal femoral morphology.

Patients and Methods

A total of 350 consecutive uncemented THA in 320 patients were performed between 1983 and 1987, by a single surgeon using the Taperloc femoral component. The 63 patients (68 hips) with Dorr type C proximal femoral morphology were the focus of this review. The mean age of the patients was 69 years (24 to 88) and mean follow-up was 16.6 years (ten to 29). Survival analysis included eight patients (eight hips) who died without undergoing revision surgery prior to obtaining ten years follow-up. All 55 surviving patients (60 hips) were available for clinical assessment and radiographic review. As a comparator group, the survival and implant fixation in the remaining 282 THAs (257 patients) with Dorr type A and B morphology were evaluated. The mean age of these patients was 52 years (20 to 82).

Results

In the Dorr C patient group the mean Harris hip score improved from 51 points (21 to 69 points) pre-operatively to 89 (74 to 100) at final follow-up. No femoral component was loose by radiological criteria and osteolysis was only identified around two stems (3.3%). There was one revision (1.6%) of a well-fixed femoral component for sepsis at 11 years. The survival of the Taperloc femoral component at 20 years with revision for any reason as the endpoint was 98% (95% confidence interval; 87 to 99). A total of ten (3.5%) of the Dorr A and B patient group of 282 THAs required revision surgery. Only one (0.4%) for aseptic loosening. A total of two hips (1%) were loose by radiographic criteria and osteolysis occurred around 12 hips (4%).

Conclusion

This study demonstrates that excellent fixation can be achieved using the Taperloc stem in patients with Dorr type A and B, and Dorr type C bone. Take home message: The Taperloc stem demonstrated equivalent results in Dorr type A and B and Dorr type C bone. Cite this article: Bone Joint J 2016;98-B:595–600.

Three-Dimensional Analysis of the Contact Pattern between the Cortical Bone and Femoral Prosthesis after Cementless Total Hip Arthroplasty

The cementless stem Excia (B. Braun, Melsungen, Germany) implant has a rectangular cross-sectional shape with back-and-forth flanges and a plasma-sprayed, dicalcium phosphate dihydrate coating from the middle to proximal portion to increase initial fixation and early bone formation. Here, the conformity of the Excia stem to the femoral canal morphology was three-dimensionally assessed using computed tomography. Forty-three patients (45 hips) were examined after primary total hip arthroplasty with a mean follow-up of 27 ± 3 months (range: 24–36 months). Spot welds occurred at zone 2 in 16 hips and at zone 6 in 24 hips, with 83% (20/24 hips) of those occurring within 3 months after surgery. First- (n = 12 hips), second- (n = 32), and third- (n = 1) degree stress shielding were observed. The stem was typically in contact with the cortical bone in the anterolateral mid-portion (100%) and posteromedial distal portions (85%). Stress shielding did not progress, even in cases where the stems were in contact with the distal portions. The anterior flange was in contact with the bone in all cases. The stability of the mid-lateral portion with the dicalcium phosphate dihydrate coating and the anterior flange may have inhibited the progression of stress shielding beyond the second degree.

Uncemented total hip arthroplasty using a tapered femoral component in obese patients: an 18-27 year follow-up study

The purpose of this study was to evaluate the efficacy of an uncemented tapered femoral component in obese patients at a mean follow-up of 23 years. We retrospectively reviewed 119 consecutive uncemented total hip arthroplasties in 105 obese patients using a tapered femoral component between 1983 and 1987. The mean body mass index of these patients was 34 (range 30-47). Complete clinical and radiographic follow-up was obtained on the 55 hips in 47 patients who survived a minimum of 18 years (range 18-27 years). Three femoral components (6%) have been revised, none for aseptic loosening. One was loose by radiographic criteria. These results demonstrate that an uncemented tapered stem can provide excellent fixation in obese patients out to 27 years.

Good short-term outcome of arthroplasty with Wagner SL implants for unstable intertrochanteric osteoporotic fractures

The purpose of this study was to evaluate the clinical and radiologic results of a consecutive series of Wagner SL arthroplasties in patients with unstable intertrochanteric osteoporotic fractures. Forty-seven consecutive arthroplasties for unstable intertrochanteric fractures using Wagner SL hip stems were studied. All patients had bone mineral density less than -2.5 SD. At average follow-up of 2.7 years, mean Harris Hip Scores were 89.4 (range, 65-100) and 87.7 (range, 57-100) for total hip arthroplasties and hemiarthroplasties, respectively. Twenty-one patients (53.8%) had excellent Harris Hip Scores (>90, 14 [35.9%]). Evidence of clinical and radiologic healing was first noted at a mean follow-up of 3.7 months (3-5 months). Wagner SL hip arthroplasties for unstable intertrochanteric osteoporotic fractures have favourable short-term clinical and radiological outcomes.

Four- to six-year follow-up of primary THA using contemporary titanium tapered stems

Tapered cementless femoral components have been used in total hip arthroplasty constructs for more than 20 years. In the past 5 to 10 years, these stems have gained popularity in the United States. The purpose of this study was to evaluate the results of the authors’ initial experience using a contemporary tapered, proximally porous-coated, titanium femoral component at 4 to 6 years of follow-up. Eighty-eight patients underwent 100 total hip arthroplasties using the Summit stem (DePuy, Warsaw, Indiana) and a cementless acetabular component. Average age at the time of surgery was 61.6 years. Patients were prospectively followed for 4 to 6 years or until death. Patients were evaluated clinically using Harris Hip Scores and the need for revision. Radiographs were evaluated for femoral loosening and osteolysis. At final follow-up, no hips had been revised for femoral or acetabular loosening. Two hips required revision for dislocation and 1 for early femoral fracture. Bony ingrowth was seen in all but 2 femoral components. There was 1 instance of proximal femoral osteolysis and none distally on radiographs (cross-linked polyethylene was used in 73% of cases). There were 2 cases of severe stress shielding. One percent of cases had an early fracture (too tight) and 1% subsided without ingrowth (too loose). One patient reported significant thigh pain that did not limit activity. At final follow-up, the Summit femoral component demonstrated durable results at 4 to 6 years. Stability of the implant without femoral fracture is paramount.

The cementless anatomic Benoist Girard (ABG) II total hip arthroplasty: a minimum 8-year follow-up study

We have evaluated 90 consecutive primary cementless ABG II total hip replacements. The bearings combined metal-on-polyethylene in 64 hips, and alumina-on-alumina in 26 hips. At the minimum 8-year follow-up, ten patients had died, seven had been lost to follow-up, two had undergone revision of either or both components, and 68 were still alive and had not been revised. With revision for any reason as the endpoint, the cumulative survival rate at 10years was 97.5%±1.7%, and 98.7%±1.3% for the metal-back cup and the femoral component, respectively. No hip showed peri-acetabular osteolysis. The ABG II total hip arthroplasty has demonstrated favourable clinical and radiological outcomes as well as survival in the current series. Further follow-up is needed to confirm these mid-term results.

Is a cementless dual mobility socket in primary THA a reasonable option?

BACKGROUND

Dislocation after THA continues to be relatively common. Dual mobility sockets have been associated with low dislocation rates, but it remains unclear whether their use in primary THA would not introduce additional complications.

QUESTIONS/PURPOSES

We therefore asked whether a current cementless dual mobility socket (1) reduced the dislocation rate after primary THA, (2) provided a pain-free and mobile hip, and (3) provided durable radiographic fixation of the acetabular component without any unique modes of failure.

METHODS

We retrospectively reviewed 168 patients who underwent primary THA using a dual mobility socket between January 2000 and June 2002. The average age at surgery was 67 years. We assessed the rate of dislocation, hip function, and acetabular fixation on serial radiographs. Of the 168 patients, 119 (71%) had clinical and radiographic evaluation at a minimum of 5 years (mean, 6 years; range, 5-8 years).

RESULTS

A long-neck option left the base of the Morse taper uncovered in 53 hips. Four patients underwent revision for dislocation between the femoral head and the mobile insert (intraprosthetic dislocation) at a mean 6 years; all four revisions occurred among the 53 hips with an incompletely covered Morse taper.

CONCLUSIONS

A current cementless dual mobility socket was associated with a pain-free and mobile hip and durable acetabular fixation without dislocations if the long-neck option was not used. However, intraprosthetic dislocation related to contact at the femoral neck to mobile insert articulation required revision in four hips. Surgeons should be aware of this specific complication.

LEVEL OF EVIDENCE

Level IV, therapeutic study. See Instructions for Authors for a complete description of levels of evidence.

Long-term follow-up results of a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels

PURPOSE

We evaluated the results of more than 10 years of follow-up of total hip arthroplasty using a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels.

MATERIALS AND METHODS

One hundred five patients (129 hips) who underwent surgery between 1991 and 1996 for primary total hip arthroplasty using cementless straight distal fluted femoral stems were followed for more than 10 years. Ninety-four hips in 80 patients were available for clinical and radiologic analysis. The mean age at the time of surgery was 47 years, and the mean duration of follow-up was 14.3 years.

RESULTS

The mean Harris hip scores had improved from 58 points to 88 points at the time of the 10-year follow-up. Activity-related thigh pain was reported in nine hips (10%). At the last follow-up, 93 stems (99%) were biologically stable and one stem (1%) was revised because of loosening. No hip had distal diaphyseal osteolysis. Proximal femoral stress-shielding was reported in 86 hips (91%). We found no significant relationship between collar-calcar contact and thigh pain, stem fixation status, or stress-shielding. The cumulative survival of the femoral stem was 99% (95% confidence interval, 98-100%) after 10 years.

CONCLUSION

The long-term results of total hip arthroplasty using a second-generation cementless femoral prosthesis with a collar and straight distal fixation channels were satisfactory; however, the high rate of proximal stress-shielding and the minimal effect of the collar indicate the need for some changes in the stem design.

Total hip arthroplasty with an uncemented tapered femoral component in patients younger than 50 years

The purpose of the present study was to evaluate the outcome of primary uncemented total hip arthroplasty in patients younger than 50 years using the Taperloc (Biomet, Warsaw, Ind) femoral component. We evaluated 94 hips in 79 patients at a mean follow-up of 16 years (range, 11-18.5 years). The average age of the patients at the time of surgery was 36 years (range, 20-49 years). Three femoral components had been revised, none for aseptic loosening. Complete clinical and radiographic follow-up was obtained on the 91 hips that had not undergone femoral component revision. The mean Harris hip score increased from 54 points (range, 20-72) before surgery to 93 points (range, 68-100) at the time of this review. Radiographically, 89 stems (98%) were determined to have fixation by bone ingrowth, 2 (2%) demonstrated stable fibrous ingrowth, and no femoral component was loose. Distal femoral osteolysis was identified in 1 hip (1%). These findings indicate that excellent clinical and radiographic results can be achieved in young patients with the Taperloc femoral component at a mean follow-up of 16 years.

Cementless total hip replacement using second-generation components: a 12- to 16-year follow-up

We reviewed 123 second-generation uncemented total hip replacements performed on 115 patients by a single surgeon between 1993 and 1994. The acetabular component used in all cases was a fully porous-coated threaded hemispheric titanium shell (T-Tap ST) with a calcium ion stearate-free, isostatically compression-moulded polyethylene liner. The titanium femoral component used was a Taperloc with a reduced distal stem. No patient was lost to follow-up. Complete clinical and radiological follow-up was obtained for all 123 hips at a mean of 14 years (12 to 16). One femoral component was revised after a fracture, and three acetabular components for aseptic loosening. No additional femoral or acetabular components were judged loose by radiological criteria. Mild proximal femoral osteolysis was identified in two hips and minor acetabular osteolysis was present in four. The mean rate of penetration of the femoral head was 0.036 mm/year (0.000 to 0.227). These findings suggest that refinements in component design may be associated with excellent long-term fixation in cementless primary total hip replacement.

Prospective, randomized comparison of cobalt-chrome and titanium trilock femoral stems

The purpose of this article was to demonstrate the efficacy of a cementless, flat, tapered wedge femoral stem and compare cobalt-chrome and titanium femoral stems with this design. Three hundred ninety femoral stems observed for a mean of 4.7 years (2.0-8.9 years) were prospectively evaluated with clinical and radiographic follow-up. Hips were stratified by Dorr classification, bone stock (femoral index), size of implant used, and material of femoral implant. Survivorship of the femoral stem at 8.9 years was 99.8% with no significant difference between cohorts. Thigh pain (4.9%) was more common with cobalt-chrome femoral stems (6.5%) than titanium femoral stems (3.1%). The flat, tapered wedge femoral stem design provides excellent femoral reconstruction in total hip arthroplasty. On the basis of this study, we use titanium femoral stems.

Long term results of the Corin C-Fit uncemented total hip arthroplasty in young patients

INTRODUCTION

We conducted a prospective study to evaluate the long-term results after Corin C-Fit uncemented total hip arthroplasty in young patients with hydroxyapatite or porous coated components.

MATERIALS AND METHODS

We prospectively followed 36 patients (38 hips) who had Corin C-Fit uncemented total hip arthroplasties by eight experienced consultant surgeons at two centres. The acetabular and femoral components were hydroxyapatite or porous coated.

RESULTS

The overall 10-year survival rate for the Corin C-Fit arthroplasty was 43%. The 10-year survivorship for the femoral implant was 56% and for the acetabular component 59%.

CONCLUSION

The evidence presented in this study suggests that the Corin C-Fit uncemented total hip arthroplasty has one of the highest mid- and long-term failure rates for both femoral and acetabular components in the literature. We believe this implant should not be used and patients who have had this form of total hip arthroplasty should be kept under regular review.

The outcome of total hip replacement in obese and non-obese patients at 10- to 18-years

We studied a consecutive series of 285 uncemented total hip replacements in 260 patients using the Taperloc femoral component and the T-Tap acetabular component. The outcome of every hip was determined in both living and deceased patients. A complete clinical and radiological follow-up was obtained for 209 hips in 188 living patients, followed for a mean of 14.5 years (10 to 18.9). They were divided into two groups, obese and non-obese, as determined by their body mass index. There were 100 total hip replacements in 89 patients in the obese cohort (body mass index ≥ 30 kg/m2), and 109 in 99 non-obese (body mass index < 30 kg/m2) patients. A subgroup analysis of 31 patients of normal weight (body mass index 20 kg/m2 to 25 kg/m2) (33 hips) and 26 morbidly obese patients (body mass index ≥ 35 kg/m2) (30 hips) was also carried out.

In the obese group five femoral components (5%) were revised and one (1%) was loose by radiological criteria. Femoral cortical osteolysis was seen in eight hips (8%). The acetabular component was revised in 57 hips (57%) and a further 17 (17%) were loose. The mean Harris hip score improved from 52 (30 to 66) pre-operatively to 89 (49 to 100) at final follow-up. Peri-operative complications occurred in seven patients (7%).

In the non-obese group six (6%) femoral components were revised and one (1%) was loose. Femoral cortical osteolysis occurred in six hips (6%). The acetabular component was revised in 72 hips (66%) and a further 18 (17%) were loose. The mean Harris hip score increased from 53 (25 to 73) prior to surgery to 89 (53 to 100) at the time of each patient’s final follow-up radiograph.

No statistically significant difference was identified between the obese and non-obese patients with regards to clinical and radiological outcome or complications. The subgroup analysis of patients of normal weight and those who were morbidly obese showed no statistically significant difference in the rate of revision of either component.

Our findings suggest there is no evidence to support withholding total hip replacement from obese patients with arthritic hips on the grounds that their outcome will be less satisfactory than those who are not obese.

Cementless total hip arthroplasty in patients 50 years or younger

This report examines the mean 9-year results of 100 second-generation cementless total hip arthroplasty in 91 patients 50 years or younger. The mean age at arthroplasty was 39 years (range, 14-50 years), and follow up averaged 9 years (range, 5-13 years). There were 13 revisions (7 related to polyethylene wear and/or osteolysis, 5 for instability, and 1 for infection). No femoral components were revised for loosening and none were radiographically loose. Two acetabular shells were revised for loosening secondary to extensive osteolysis. Ten-year survivorship using revision for any reason as the end point was 87.5%, using femoral component aseptic loosening as the end point was 100%, and using acetabular component aseptic loosening as the end point was 97.1%.

Strain adaptive bone remodelling in total joint replacement

Histomorphologic analyses of artificial joint components implanted into bone need special technology for processing and for documentation; published histological work systematically done therefore is rare. The histopathology, three-dimensionally analyzed in a complete sequence of sections is, however, the only precise answer in terms of biocompatibility and bone response. A complete analysis allows a type-related predictable prognosis of an implantation that is at least comparable to a finite element analysis with respect to load transfer to host bone. The histopathologic collection of the ZOW Munich is comprised of more than 5000 nondemineralized bone and joint specimens and more than 500 artificial joint components implanted in the human skeleton for up to 25 years. Fifty-nine implant-bone specimens without signs of loosening already have been processed and analyzed systematically. According to the strain-adapted bone remodelling, different types of anchorage clearly were differentiated and their morphologic substrate could be worked out. Based on that, the cemented standard anchorage could be distinguished histologically from the cemented press-fit procedure, and the noncemented press-fit from the porous ingrowths pattern. In terms of the topography of the bony integration, the proximal and distal press-fit and ingrowth pattern were analyzed; beside that, the cemented and noncemented epiphyseal resurfacings could be defined histologically. In all histologic specimens the remodelling appeared as a result of stress-related strain, reflecting stiffness of the implant and the resistance of bone to deformation. It clearly was worked out that all success of cemented components is based on preserved cancellous bone honeycombs stiffened by bone cement, representing an adaptation of bone in terms of stiffness to the stiff implants.

Thirteen year results of total hip arthroplasty using a tapered titanium femoral component inserted without cement in patients with type C bone

Although cementless arthroplasty with a tapered titanium femoral component has proven reliable in young patients with excellent bone quality, studies involving patients with poor bone quality are lacking. The present study evaluates the results of total hip arthroplasty (THA) using such a femoral component in patients with Type C femoral bone. Ninety-two THAs were performed in 81 patients aged 65 years and older using a tapered titanium cementless femoral component. Follow-up in 62 patients (72 hips) averaged 13.2 years (minimum, 10 years); 19 patients were lost to follow-up. According to Door's criteria, 20 femora were classified as Type A, 19 as Type B, and 33 as Type C. No stem was revised because of stem instability, thigh pain, or osteolysis. One stem was removed because of sepsis. Six acetabula were revised because of polyethylene wear and periacetabular osteolysis. Four patients reported mild thigh pain. Radiologic signs of osseous integration for cylindrical extensively porous coated cobalt-chrome femoral components are not valid for tapered titanium designs.

Plasma spray-coated Ti femoral component for cementless total hip arthroplasty

A retrospective study of the clinical and radiographic results of Mallory Head total hip arthroplasties in 67 patients (76 hips) with a mean age of 50.1 years was undertaken. The mean follow-up period was 10.1 years (9-13years). In this study, excellent or good clinical results were found for 64 patients. Minimal thigh pain was found in 3 patients (4.4%). Seventy-one hips (93.4%) showed fixation by bony ingrowth and 3 (3.9%) showed stable fibrous fixation. Bony ongrowth and ingrowth were also seen in 16 hips (21%) at distal smooth and grit-blast areas. Two femoral components were revised (survival rate, 97.3%), one for subsidence and other for recurrent infection. We believe that these good results were caused by excellent bony ingrowth on the proximal two thirds of the femoral surface area. In conclusion, proximal plasma-spray coating and the tapered shape of the Ti stem showed excellent bony ingrowth and initial stability. Our results indicate that the tapered shape will be an important element in the design of a cementless Ti stem.

Primary total hip arthroplasty using a grit-blasted, press-fit femoral prosthesis.Long-term results with survivorship analysis

BACKGROUND

This report presents the initial experience with the use of a grit-blasted, press-fit femoral prosthesis.

METHODS

The first 300 consecutive primary total hip arthroplasty procedures using a collarless, three-dimensional tapered, straight, titanium alloy stem with a grit-blasted surface (performed in 299 patients) were evaluated with independent clinical and radiographic follow-up examinations up to sixteen years. Eight different types of acetabular components, including a cementless all-polyethylene socket in 80 percent of the cases, were used. Radiographic evaluation, performed by an independent observer using a zonal analysis method, included assessment of component migration, Enghs implant-bone femoral fixation score, implant-bone demarcations, and periprosthetic osteolysis. The average duration of long-term radiographic follow-up was 12.6 years (range; 10 to 16 years).

RESULTS

At last examination only five hips were lost to follow-up and 69 patients were deceased. The overall mechanical failure rate (i.e. unstable with or without revision) of the femoral component was 2 percent. The femoral revision rate was 7 percent (two hips for aseptic loosening, five hips for septic loosening, and twelve hips with osseointegrated stems for severe progressive femoral osteolysis) and the acetabular revision rate was 27 percent (revised for either socket migration or progressive peri-acetabular osteolysis or both). Survivorship, based on any revision (femoral or acetabular) was 89 percent at ten years and 62 percent at fourteen years; survivorship of the femoral component was 95 percent at ten years and 90 percent at fourteen years. The incidence of femoral periprosthetic osteolysis, by radiographic examination at ten years or more was 47 percent, including 12 hips (5 percent) with distal endosteal osteolysis. Femoral implant-bone fixation was stable, bone-ongrowth in 97 percent; stable, fibrous-fixation in 1 percent, and unstable, fibrous-fixation in 2 percent of the cases.

CONCLUSIONS

The grit-blasted, press-fit, collarless, tapered femoral component continued to per-form well clinically and radiographically up to sixteen years of follow-up despite the challenging environment of periprosthetic osteolysis associated with the acetabular component design. The high incidence of failure among the cementless all-polyethylene sockets was not unexpected and the use of this acetabular implant was discontinued in 1985. While considered a "first-generation" cementless stem, this implant is still in use virtually without design modifications. This study demonstrates the durability of the results of the grit-blasted femoral component and indicates that such an implant offers a viable alternative for fixation without bone cement. (Hip International 2002; 2: 55-72).

Analysis of the results of the C-Fit uncemented total hip arthroplasty in young patients with hydroxyapatite or porous coating of components

Young patients at 2 separate centers received a C-Fit uncemented arthroplasty, with randomization to porous or hydroxyapatite coating. No difference in survival could be found between components that were porous or hydroxyapatite coated, with 27.5% being revised within 8 years, mainly for aseptic loosening. Acetabular augmentation screws or offset acetabular liners similarly did not affect outcome. Two of the offset liners had spun within the metal acetabular liners, with early failure. Some of the survivors showed poor clinical scores, but there was no correlation between clinical score and radiographic evidence of loosening. These results are comparable to the poorest reported survival figures in the literature for uncemented prostheses. Prosthesis coating could not be shown to affect component survival for this prosthesis.

Primary total hip arthroplasty with the AML total hip prosthesis

Primary total hip arthroplasty using an uncemented AML total hip prosthesis (trispiked cup and a 4/5 porous coated stem) was performed in 50 patients (52 hips). The average age of the patients at the time of surgery was 47.6 years (range, 19-68 years), and the diagnosis was osteonecrosis of the femoral head in 18 hips, osteoarthritis in 16, fracture of the femoral neck in 14, osteoarthrosis secondary to childhood pyogenic arthritis in two, childhood tuberculous arthritis in one, and traumatic arthritis in one. The average followup was 11.3 years (range, 11-12 years). The average preoperative Harris Hip Score was 59 points, which improved to 90 points. Twenty-five (48%) hips had excellent results, 14 (27%) had good results, three (6%) had fair results, and 10 (19%) had poor results. The overall rate of revision was 15% (eight hips). The rate of revision of the femoral component was 2% (one hip), and the rate of revision of the acetabular component was 15% (eight hips). Twenty (38%) hips had acetabular and femoral osteolysis. Nine (17%) hips had femoral osteolysis only. Thirty-four (65%) hips had an average of 3.3 mm (range, 2-12 mm) of wear in the polyethylene liner. The average wear rate was 0.29 mm (range, 0.17 to 1.04 mm) per year.

The effects of cobalt chromium upon macrophages

The purpose of this study was to elucidate the mechanisms by which cobalt chromium particulate wear debris contribute to the aseptic loosening of total joint prostheses. Incubation of macrophages with cobalt chromium led to release of tumor necrosis factor-alpha (TNF-alpha) and prostaglandin E2 (PGE2), but did not lead to release of interleukin-1 beta (IL-1 beta) or interleukin 6 (IL-6). Exposure of macrophages cocultured with osteoblasts to cobalt chromium also led to significant release of TNF-alpha and PGE2, but did not lead to significant IL-6 or IL-1 beta production. The release of PGE2 in the coculture system was greater than that detected when macrophages were exposed to cobalt chromium without the osteoblast contribution. Exposure of radiolabeled calvaria to media from macrophages incubated with cobalt chromium in coculture with osteoblasts led to release of 45Ca. In contrast, exposure of radiolabeled calvaria to media from isolated macrophages incubated with these particles did not result in release of 45Ca. Exposure of macrophages to cobalt chromium was toxic, as reflected by release of the intracellular enzyme lactate dehydrogenase. Macrophages play a role in the initiation of bone resorption at the interface through the phagocytosis of cobalt chromium particles and subsequent release of TNF-alpha and PGE2. The presence of osteoblasts at the interface may be required for amplification of the inflammatory response and ultimately for bone resorption.

Host-bone response to porous-coated cobalt-chrome and hydroxyapatite-coated titanium femoral components in hip arthroplasty. Dual-energy x-ray absorptiometry analysis of paired bilateral cases at 5 to 7 years

Uncemented porous-coated cobalt-chrome femoral stems have produced satisfactory short-term clinical results, although slightly inferior to the results of cemented total hip arthroplasty. Proximal femoral bone resorption, osteolysis and fibrous ingrowth have been reported with porous-coated stems. Hydroxyapatite-coated stems and titanium stems have been introduced to avoid these findings through improved fixation. Dual-energy x-ray absorptiometry allows quantitative examination of bone density changes after uncemented total hip arthroplasty. This study examines the host-bone response to hydroxyapatite-coated titanium and porous-coated cobalt-chrome stems of identical geometry in three paired bilateral cases at 5 to 7 years. Distinctly different patterns of femoral bone mineral density changes were observed with the two stem designs. The authors conclude that dual-energy x-ray absorptiometry is a promising technique allowing noninvasive analysis of uncemented stem fixation, and that the data from this study suggest improved fixation and stress transfer with hydroxyapatite-coated titanium stems.

The Wisconsin noncemented femoral stem. A prospective study with 5 to 9 years of follow-up evaluation

In an attempt to decrease aseptic loosening, total joint components are now being used without cement. Most components are designed to achieve fixation biologically. The radiographic results of 144 primary uncemented total hip arthroplasties and the clinical results of 89 arthroplasties that were performed using a proximally porous-coated titanium alloy femoral stem between November 1983 and June 1989 are reported. On the acetabular side, a threaded component or a hemispherical porous-coated component was used. The patients were followed prospectively for 5 to 9 years postsurgery. During the study period, the threaded acetabular component had a high failure rate. Because it was not possible to determine accurately from which component a particular sign or symptom arose, clinical analysis was restricted to only those hips without a failed or revised cup. Eighty-nine hips in 71 patients with a minimum follow-up period of 5 years were available for clinical review. Radiographic review of the femoral stem was completed on all hips with 5 or more years of radiographic follow-up evaluation regardless of the status of the acetabular component. One hundred twelve hips in 85 patients were analyzed radiographically. At a latest mean follow-up period of 6.7 years, the mean Iowa hip score was 91.4 +/- 8.0 with a 5.4% incidence of thigh pain. Throughout the follow-up period, the patients with thigh pain had a statistically lower mean Iowa pain subscore when compared with those patients without thigh pain (P=.0001). Endosteal erosion was seen in two hips (1.8%) and longitudinal loss of the medial neck greater than 2 mm was noted in two hips. One femoral stem was revised for aseptic loosening. The clinical results of this femoral stem equal or exceed the published accounts of other arthroplasties. The results indicate that the stem is associated with good clinical results, minimal bone loss, and little osteolysis. Continued follow-up evaluation of patients with this femoral stem is necessary to assess the durability of these encouraging results.

Prostheses for primary total hip replacement. A critical appraisal of the literature

Eighty-one published papers on the performance of prostheses in total hip replacement were appraised. Sound methodology was demonstrated in 1 of 8 randomized controlled trials and 4 of 17 nonrandomized comparative studies. Of 56 case series without controls, 32 met the appraisal criteria, but these are intrinsically less useful. The published literature does not provide solid evidence for the superiority of cement-free or hybrid prostheses over modern cemented types.

[Results of implantation of uncemented porous metal hip prostheses]

72 patients having cementless spongy-metal hip prosthesis were reexamined by clinical and radiological check up two to seven years after implantation (average 43 months). In case of five patients hip prosthesis had to be changed due to loosening (no bony ingrowth n = 2, loosening of acetabular component due to technical faults n = 3). In correlation to clinical results 88% could be considered as excellent or good, 9% acceptable and 3% as inadequate. 10% of the patients complained about thigh pain. The typical radiological bony reactions of the surrounding bone are described. An evaluation of the radiological results can only be done under consideration of the clinical problems involved. In view of the positive results obtained in the recent time the use of spongy-metal hip prosthesis can be recommended for cementless hip joint replacement in case of younger patients. Especially in case of cemented hip joints which have become loose it will be an advantage to use spongy-metal hip prosthesis.