Bipolar femoral head arthroplasty in osteoarthritis. A prospective study with a minimum 5-year follow-up period

Long-Term Outcomes of Cementless Bipolar Hemiarthroplasty in Young Patients With Osteonecrosis of the Femoral Head: The Impact of Implant Improvements and Preoperative Stage

Introduction Advancements in bipolar hemiarthroplasty (BHA) implants in the mid-1990s contributed to favorable short-term outcomes for osteonecrosis of the femoral head (ONFH), particularly in cases without acetabular cartilage lesions. Nevertheless, long-term results remain unclear. In this study, we investigated (i) the impact of new-generation BHA implants and (ii) the effect of the preoperative stage on long-term outcomes in young patients with ONFH. Methods The records of consecutive patients with ONFH who underwent cementless BHA were retrospectively reviewed. Patients aged ≥60 years, with <10 years of follow-up, or who underwent acetabular reaming during surgery were excluded. Radiographical and clinical outcomes of patients who received first-generation BHAs and new-generation BHAs (developed after 1998) were compared by stratifying based on preoperative stage 2/3A and 3B/4, according to the Japanese Investigation Committee classification. Results Overall, 50 hips from 39 patients (mean age: 44.6 years; 64% male) with an average follow-up of 18.6 years were included. The frequency of advanced-stage patients was significantly higher in the first-generation BHA group than in the new-generation group. Regarding postoperative outcomes, the first-generation BHA group had higher acetabular erosion grades (p<0.001) and more femoral component loosening than those in the new-generation group (p<0.001). Revisions were performed in eight hips (seven in the first-generation and one in the new-generation BHA groups, p<0.001). In the new-generation BHA group, there were no significant differences in patient background between stage 2/3A and 3B/4 groups, and only one case in the stage 3B/4 group required revision. In the new-generation group, the grade of acetabular erosion was significantly higher for stage 3B/4 than stage 2/3A (p<0.001); other radiographical and clinical outcomes did not differ significantly between stages. Conclusion New-generation BHAs have significantly better implant survival rates for early-stage ONFH than those of first-generation BHAs. These findings indicate that BHA is an acceptable treatment option for early-stage ONFH in young patients.

Midterm results of revision total hip arthroplasty for migrated bipolar hemiarthroplasty in patients with hip osteoarthritis using cementless cup with the rim-fit technique

PURPOSE

The results of reamed bipolar hemiarthroplasty (BHA) in patients with hip osteoarthritis (OA) are reported to be unfavorable. Acetabular reaming for sufficient bony coverage caused bipolar head migration into the superomedial direction, and most patients required revision surgeries. Several methods are applicable to treat decreased bone stock. This study aimed to investigate the midterm results of revision surgeries using the cementless cup with the rim-fit technique.

METHODS

Between 1996 and 2014, acetabular revision surgeries using the cementless cup with the rim-fit technique were performed in 86 hips (74 patients). We evaluated radiographic outcomes, including positional change of the rotation center of the artificial femoral head, presence of implant loosening, and filling of the initial gap. We also evaluated clinical outcomes, including the Harris hip score (HHS), and postoperative complications.

RESULTS

The average positional changes from BHA to prerevision surgeries were 8.0 mm superiorly and 4.1 mm medially. The average changes from prerevision to postrevision surgeries were 3.7 mm inferiorly and 2.4 mm laterally. No implant loosening was found in all cases; the initial gap between the acetabular host bone and the acetabular cup was filled in 53 (93%) among 57 hips. The average HHS improved from 65.9 before revision surgeries to 83.8 in the latest follow-up. Dislocation and postoperative periprosthetic fracture occurred in two and five hips, respectively; no cases required rerevision surgeries.

CONCLUSION

There were favorable midterm results of the revision total hip arthroplasty for migrated BHA in patients with hip OA using cementless cup with the rim-fit technique.

Disassembly of bilateral bipolar heads within 10 years after hip hemiarthroplasties for avascular necrosis of femoral heads: a case report

Prosthetic joint surgeries, total hip arthroplasty (THA) or bipolar hemiarthroplasty (BHA) and joint preservation surgeries can be performed for avascular osteonecrosis of femoral head (ONFH) with collapse. Although excellent surgical results have been reported, long-term survivorship and postoperative complications are a great concern. The purpose of this study was to report a case of bilateral disassembly of bipolar heads within 10 years after BHA for ONFH. A 61-year-old man, whose occupation was carpenter, underwent bilateral BHA for ONFH at another hospital when he was 57 years old. He had acute right hip pain during working and visited our institute. Radiographs revealed intra-articular (outer and inner head) disassembly of the right bipolar head, and conversion to THA was performed. Five years later, he had contralateral (left) hip pain. Radiographs revealed disassembly of bipolar head, as had occurred with the right hip, and similar conversion surgery was performed for the left hip. Marked wear and detachment of the polyethylene bearings of the outer head and failure of the locking mechanism between a skirted 22-mm-diameter inner head and polyethylene insert were observed in both hips at each revision surgery. Degeneration of the acetabulum were also observed in both hips. The failure of the self-centering mechanism because of degenerative change of the acetabulum, impingement of the outer head and neck, and high activity seemed to be the causes of disassembly of the bilateral bipolar heads. Therefore, it is important to select the type of prostheses depending on the age, activity and occupation of each patient.

Range of Motion Simulation of Hip Joint Movement During Salat Activity

BACKGROUND

Impingement of an artificial hip joint because of limited range of motion (RoM) during human activity is one of the main sources of hip joint failure. The aim of this article is to simulate the RoMs of hip joints during salat, the practice of formal worship in Islam.

METHODS

Salat consists of several stages which can be represented with a cycle (raka'ah). Every raka'ah consists of standing, bowing (ruku'), straightening up (i'tidal), transition of standing toward prostrating, prostrating (sujud), and sitting. A virtual skeleton model was used to analyze the motion during salat for the possibility of the impingement occurrence.

RESULTS

The results of the simulation were presented in terms of maximum flexion, abduction, and internal or external rotation. The results also showed that the prostration position is similar in RoM with the Japanese zarei position and similar in RoM to pick up an object while sitting on a chair.

CONCLUSION

Specific aspects of salat such as the difference in position of the 2 legs at the last sitting position create an extreme RoM which in turn results in a high risk of impingement.

Bipolar hip arthroplasty for avascular necrosis of femoral head in young adults

BACKGROUND

Bipolar hip arthroplasty (BHA) is one of the options for treatment of avascular necrosis (AVN) of the femoral head. Acetabular erosion and groin pain are the most allowing for gross motion between the common complications. We propose that these complications are secondary to improper acetabular preparation allowing for motion between the BHA head and the acetabulum.

MATERIALS AND METHODS

The current study retrospectively evaluated patients'records from case files and also called them for clinical and radiological followup. 96 hips with AVN of the femoral head treated with BHA were included in the study. All patients were males with a mean age of 42 years (range 30-59 years). In all cases, the acetabulum was gently reamed till it became uniformly concentric to achieve tight fitting trial cup. Clinical followup using Harris hip score (HHS) and radiological study for cup migration were done at followup.

RESULTS

The mean followup was 7.52 years (range 4-16 years). The HHS significantly improved from a preoperative value of 39.3 (range, 54-30) to a postoperative value of 89.12 (range 74-96). According to HHS grades, the final outcome was excellent in 52 hips, good in 28 and fair in 16 hips. Hip and groin pain was reported in four hips (5%), but did not limit activity. Subsidence (less than 5 mm) of the femoral component was seen in 8 cases. Subgroup analysis showed patients with Ficat Stage 3 having better range of motion, but similar HHS as compared to Ficat Stage 4 patients.

CONCLUSION

Bipolar hip arthroplasty (BHA) using tight fitting cup and acetabular reaming in AVN hip has a low incidence of groin pain, acetabular erosion and revision in midterm followup. Good outcome and mid term survival can be achieved irrespective of the Ficat Stage.

Comparative Outcomes Assessment: Hip Hemiarthroplasty as an Alternative to THA in Patients with Surgically Pristine Acetabulum-Is There Still a Role?

This is a retrospective review of 243 hip arthroplasties treated with either hemiarthroplasty (61 surgeries-Group 1) or total hip arthroplasty (182 surgeries-Group 2). The mid- to long-term results of relatively similar, predominately young patient cohorts were assessed annually via radiographs and the Harris Hip Scores for pain and clinical function. Groin pain persisted in 16.4% of Group 1 and 5.5% of Group 2 (P = 0.0159). Thigh pain persisted in 11.5% of Group 1 and 2.2% of Group 2 (P = 0.0078). Complications in Group 1 were 4/61 including 2 revisions with an overall survival rate of 96.7% versus Group 2 complication rate of 29/182 with 15 revisions and an overall survival rate of 91.8%. There were no cases of acetabular protrusio in Group 1, but 2 cases (1%) in Group 2 had cup loosening or osteolysis. Two cases were revised in Group 1 (3.2%). Both were undersized femoral stems. The fifteen revisions (8.2%) in Group 2 included loose stem (1), instability (8), infections (3), cup loosening (2), and accelerated polyethylene wear (1). Hemiarthroplasty has a higher incidence of thigh and groin pain but fewer complications compared with total hip arthroplasty.

Long-term results of bipolar hemiarthroplasty for osteoarthritis of the hip and idiopathic osteonecrosis of the femoral head

BACKGROUND

Satisfactory results have been reported from long-term studies on bipolar hemiarthroplasty for femoral neck fracture. However, long-term results of this procedure for osteoarthritis of the hip (OA) and idiopathic necrosis of the femoral head (ION) have given rise to pessimism. These poor results have often reported migration of the bipolar head, but few had described the direction of this migration. The purpose of the present study was to conduct a long-term follow-up analysis of bipolar hemiarthroplasty for OA and ION, including the direction of migration.

METHODS

We retrospectively reviewed a consecutive series of 64 patients (76 hips) who underwent primary bipolar hemiarthroplasty for symptomatic OA and ION with a cementless femoral component between 1976 and 1995. Of these 64 patients, 35 patients (40 hips) were available for clinical and radiographic review at a minimum follow-up duration of 10 years.

RESULTS

The Japanese Orthopaedic Association score significantly improved and pain relief was high following surgery; however, preservation of acetabular bone stock could not be achieved because of migration. The survival rate declined 10 years after surgery. Superomedial migration was found to be a risk factor for revision, and one factor affecting superomedial migration was the postoperative center edge angle.

CONCLUSIONS

The long-term results of bipolar hemiarthroplasty for OA and ION are not favorable. If a sufficient centripetal position is obtained with reaming, the bipolar head tends to migrate superomedially, subsequently requiring revision.

Minimum ten-year results of primary bipolar hip arthroplasty for degenerative arthritis of the hip

BACKGROUND

Bipolar hip arthroplasty has been advocated by some as an alternative to total hip arthroplasty for the treatment of degenerative arthritis of the hip. We sought to assess the results of this procedure at our institution after a minimum duration of follow-up of ten years.

METHODS

We retrospectively reviewed a consecutive series of 152 patients (173 hips) who underwent primary bipolar hemiarthroplasty for the treatment of symptomatic degenerative arthritis of the hip with a cementless femoral component between 1983 and 1987. Of the original cohort of 152 patients, ninety-two patients (104 hips) were available for clinical and radiographic review at a mean of 12.2 years postoperatively. At the time of the latest follow-up, self-administered Harris hip questionnaires were used to assess pain, mobility, activity level, and overall satisfaction with the procedure. Biplanar hip radiographs were made to evaluate bipolar shell migration, osteolysis, and femoral stem fixation.

RESULTS

At the time of the latest follow-up, nineteen patients (nineteen hips) had undergone revision to total hip arthroplasty because of mechanical failure, and three patients (three hips) were awaiting revision because of symptomatic radiographic mechanical failure. Twelve acetabular revisions were performed or scheduled for the treatment of pelvic osteolysis or protrusio acetabuli secondary to component migration. Acetabular reconstruction required bone-grafting, an oversized shell, and/or a pelvic reconstruction ring. The overall rate of mechanical failure was 21.2% (twenty-two of 104 hips), with 91% (twenty) of the twenty-two failures involving the acetabular component. Reaming of the acetabulum at the time of the index arthroplasty was associated with a 6.4-fold greater risk of revision. The rate of implant survival, with revision because of mechanical failure as the end point, was 94.2% for femoral components and 80.8% for acetabular components at a mean of 12.2 years. Of the remaining sixty-nine patients (eighty-one hips) in whom the original prosthesis was retained, seventeen patients (24.6%) rated the pain as moderate to severe. Nearly 30% of patients with an intact prosthesis required analgesics on a regular basis. Radiographs were available for fifty-eight hips (including all of the hips with moderate to severe pain) after a minimum duration of follow-up of ten years; twenty-eight of these fifty-eight hips had radiographic evidence of acetabular component migration.

CONCLUSIONS

This bipolar cup, when used for hemiarthroplasty in patients with symptomatic arthritis of the hip, was associated with unacceptably high rates of pain, migration, osteolysis, and the need for revision to total hip arthroplasty, especially when the acetabulum had been reamed. To the extent that these findings can be generalized to similar implant designs with conventional polyethylene, we do not recommend bipolar hemiarthroplasty as the primary operative treatment for degenerative arthritis of the hip.

Dissociation progressive intra prothétique d’une prothèse intermédiaire de hanche

Certain complications, such as acetabular erosion or cup dissociation, are specific to bipolar prostheses. Progressive intra-acetabular dislocation has not been reported to date. We report 4 cases. Four elderly women developed progressive intra-acetabular dislocation after implantation of a bipolar prosthesis for femoral neck fractures. The metal-backed cup verticalized progressively and the ball gradually dislocated into the acetabulum, eroding it. Revision was undertaken with a hemispheric bone ingrowth cup and partial grafting. Follow-up was then uneventful. This phenomenon is different from the acute intra-acetabular dislocation that may occur after rupture of the anti-dissociation mechanism (polyethylene ring) incorporated in the design of new implant models, or after dissociation between the ball and the cup during closed reduction of a dislocation, the cup catching on the acetabular rim. It is not due to a variation in the neck-head angles (we observed varus, valgus, and neutral angles) nor to a problem between the modular head and the neck (at the morse cone taper). For us, the cause of this progressive intra-acetabular dislocation is poor cup design associated with a weak retention system. If the centers of the inner and outer spheres are superimposed, the cup has a natural tendency to drop into varus because of its weight. This becomes even worse if the center of the outer sphere is medial to the ball center. The cup should be designed so that the center of the outer sphere (bipolar cup) lies lateral to the center of the inner sphere (ball) creating a valgus torque for the cup. Designing a bipolar cup is not as a simple matter as it may seem. We emphasize the importance of the position of the rotation centers.

Bipolar hemiarthroplasty in juvenile rheumatoid arthritis: long-term survivorship and outcomes

Because controversy surrounds the management of end-stage hip disease in juvenile rheumatoid arthritis (JRA), this study evaluated the long-term outcome of bipolar hemiarthroplasty as an alternative to conventional joint arthroplasty. A total of 24 JRA patients underwent 39 hemiarthroplasties; follow-up averaged 12 years (range, 3 to 15 years). There were 14 hips (36%) revised, and 25 hips (64%) maintained the original components. Mean Harris hip scores in surviving hips improved from 29 to 69 points (P<.001). Radiographs showed progressive bipolar superomedial migration (P<.01) despite attempted augmentation. Failure defined as revision to total hip arthroplasty or definite radiographic loosening occurred in 15 hips (38%). Ten-year Kaplan-Meier survivorship for all prostheses was 78%. Independent multivariate risk factors for failure included acetabular grafting (P =.006), prosthesis type (P<.001), and unilateral replacement (P<.001).

Stability of total hip arthroplasty in patients 75 years or older

Increasing patient age (> 75 years) is a known risk factor for dislocation of total hip arthroplasty. This is a study of total hip arthroplasties by one surgeon in patients 75 years or older to determine the prevalence of dislocation and a review of the surgical options for prevention and treatment of instability in this population. Of 140 primary total hip arthroplasties done in patients 75 years or older who were followed up for at least 1 year, the preoperative diagnosis was osteoarthritis in 82% and the mean followup time was 4 years. The acetabular component was cementless: modular in 121 arthroplasties and cemented in 19 arthroplasties. There were five dislocations (3.5%), but only two were recurrent and the patients were treated successfully by modular component exchange. Bipolar arthroplasty has a lower rate of dislocation, but there are problems with residual pain and high rates of reoperation, wear, and osteolysis. Constrained components may be indicated in older patients with dementia, abductor insufficiency, or failure of modular exchange. Large femoral heads, to increase the range of motion before dislocation occurs, may be used with highly cross-linked acetabular liners. Modular cementless acetabular components are preferable in patients who are 75 years or older. A 28-mm or 32-mm femoral head is recommended, but larger femoral heads should be considered in patients with fractures and for the treatment of recurrent dislocation.

Bipolar hemiarthroplasty for osteonecrosis of the femoral head. A 7- to 18-year followup

This study evaluated clinical and radiographic results of bipolar hemiarthroplasties for the treatment of osteonecrosis of the femoral head. Forty-eight hips in 35 patients with a mean age of 37 years who underwent primary bipolar hemiarthroplasties were observed for an average of 11.4 years. Osteonecrosis was associated with corticosteroid use (21 patients), alcohol (six patients), idiopathic (four patients), and other conditions (four patients). The average Harris hip score was 46 before surgery and 86 at the time of the final followup. Twenty (42%) hips were radiographic failures, and 12 (25%) hips were revised. Groin symptoms were present in 20 (42%) hips. Radiographic proximal migration greater than 4 mm and osteoarthritic signs of the acetabulum indicated a high risk of groin symptoms. The results were inferior to those previously reported for total hip arthroplasty. Thus, for the treatment of osteonecrosis of the femoral head in which necrotic lesions are wide, the authors no longer use this system and currently use total hip arthroplasty.

Degenerative changes in normal femoral heads in the elderly

Unipolar hemiarthroplasty and bipolar hemiarthroplasty are frequently chosen for treating subcapital hip fracture; however, clinical outcome varies substantially. Although total hip arthroplasty is indicated for subcapital hip fracture in patients with degenerative hip disease, there is a lack of data on the incidence and extent of degenerative change in patients with subcapital hip fracture without obvious degenerative hip disease. This investigation evaluated articular cartilage in 25 consecutive femoral heads removed from elderly patients who sustained acute femoral neck fracture. All patients' femoral heads demonstrated grade 2 or 3 chondromalacia with an average involvement of 54% of the whole femoral head surface area. Review of the literature describes the cost-to-benefit ratio associated with painful hip arthroplasty. This study demonstrated a high incidence of femoral head degenerative change, which may account for the variable clinical results and proliferation of the term unsolved fracture. In the patient with a subcapital hip fracture, total hip arthroplasty may prove to be a better alternative.