Femoral Head Dislodgement Complicating Use of a Dual Mobility Prosthesis for Recurrent Instability

The dual mobility cup is an unconstrained tripolar configuration newly introduced to the United States in February 2011. The dual mobility construct allows for a larger femoral head to improve motion and minimize the risk of dislocation. We present a case of a patient who received the dual mobility cup for the treatment of recurrent dislocation following total hip arthroplasty. Early in the patient's postoperative course, the implant failed at the articulation between the larger outer polyethylene head and inner smaller metal femoral head following an attempt at closed reduction. This implant specific complication has not been reported in the North American literature.     

Acute liner disassociation of a Pinnacle acetabular component

A primary total hip arthroplasty using a cementless Pinnacle cup and neutral Marathon polyethylene liner mated via a 32-mm cobalt chrome head to a Summit pore coated stem (Depuy, Warsaw, IN). At 23 months postoperative an acute disassociation occurred. This was resolved with a liner exchange to a 36-mm metal liner with a 36-mm metal head. The retrieved polyethylene liner was noted to have 3 of the 6 peripheral locking tabs sheared off.     

全髋关节置换术治疗成人Crowe Ⅳ型先天性髋关节脱位的临床研究

目的探讨CroweⅣ型先天性髋关节脱位患者全髋关节置换术的手术方法及预防神经损伤的对策。方法35例（39髋）CroweⅣ型先天性髋关节脱位患者行全髋关节置换术,均为女性,年龄36～56岁,平均46岁。获得随访31例35髋,随访时间1年～8年,平均4年。手术采用后外侧切口。髋臼侧除1例2髋外,均在真臼水平安放臼杯并使用非骨水泥型假体,股骨侧5例5髋选用骨水泥型假体,其余均选用非骨水泥型假体。2例2髋以往曾行转子下截骨者先行转子下截骨矫正术,再植入非骨水泥型假体。采用髋关节功能评分（Harris评分）评定髋关节功能,术前平均43分。结果获得随访的31例（35髋）中,5例5髋发生术中骨折,其中小转子轻微襞裂骨折3例3髋,大转子不全骨折2例2髋,但股骨假体稳定,予钢丝固定或未作特殊处理。3髋发生异位骨化,均为BrookⅡ型。2例术后分别出现坐骨神经或股神经刺激症状,1个月后恢复正常。随访期间内无一例发生术后感染、术中术后髋关节脱位、假体松动及有明显临床表现的深静脉血栓形成等并发症。术后随访时Harris评分平均87分,术后肢体延长4～6cm,平均5cm,肢体短缩得到满意纠正。结论后外侧人路、真臼水平重建髋臼是CroweⅣ型先天性髋关节脱位全髋关节置换术安全、有效的手术方法。     

Total hip arthroplasty in high dislocated and severely dysplastic septic hip sequelae

The authors analyzed a consecutive series of 20 total hip arthroplasties performed using a cementless conical stem with shortening osteotomy combined with greater trochanter transfer in cases with a highly dislocated hip secondary to sequelae of a septic hip in childhood. Mean patient age was 47.3 years and the mean follow-up period was 3.4 years. An acetabular metal cup was inserted in 5 cases, and only a liner was inserted after cementing in 15 cases. Mean Harris hip score improved from 42.4 preoperatively to 84.2 at final follow-up. Mean leg lengthening was 36.5 mm, and time to greater trochanter union was 3.72 months. No complete radiolucent line of thickness >2 mm was observed in any case. These surgical methods produced satisfactory clinical and radiological results.     

Intermediate- to Long-Term Results After Hybrid Total Hip Arthroplasty in Patients With Rheumatoid Arthritis

There have been few reports describing intermediate- to long-term results after hybrid total hip arthroplasty in patients with rheumatoid arthritis. We followed up 52 hips in 44 patients aged 5 men and 39 women, with a mean of 11.5 years (range, 5-23.5 years). Revisions had been performed in 6 hips in 6 patients: 1 both acetabular and femoral components for infection, 1 acetabular component for aseptic loosening, 3 acetabular components for recurrent dislocation, and 1 acetabular component for dislodgement of the polyethylene liner from the metal shell. None of other acetabular or femoral components were revised or found to be loose at the final follow-up. Although postoperative dislocation remains a concern, hybrid total hip arthroplasty had an acceptable result in patients with rheumatoid arthritis.     

Dissociation of the S-ROM metal-backed polyethylene acetabular liner--a case report and literature review

The authors report a case of early failure of a total hip arthroplasty with dissociation of the polyethylene liner of an S-ROM Oblong Cup*, which presented as a dislocation. Initial closed reduction of the dislocation was not possible. Open exploration of the hip revealed that the modular Poly Dial* polyethylene acetabular liner had become dislodged from the acetabular cup. The liner was revised and a stable reduction of the hip was achieved. To our knowledge, no previous case of dissociation of the polyethylene liner from the S-ROM Oblong acetabular component has been reported. A review of the literature with other relevant cases is presented.     

Mid-term results of large diameter heads on cross-linked polyethylene liners in total hip replacement

BackgroundHighly cross-linked polyethylene liners in total hip replacement (THR) have allowed the use of larger diameter femoral heads. Larger heads allow for increased range of motion, decreased implant impingement, and protection against dislocation. The purpose of this study is to assess the clinical and radiographic outcomes of patients with large femoral heads THR at 4 years postop.Materials and methodsStudy includes 28 patients who had a primary THR with a 36 mm larger femoral head were retrospectively for minimum 4 years follow-up. All patients received a cementless acetabular shell and a highly cross-linked polyethylene liner with an inner diameter of 36 mm. The median radiographic follow-up was 4 years (range 2.0–6.0), and patients were assessed clinically by Harris hip score.ResultsThe mean follow-up is minimum 4 years (range 2–6 years) results in all operated patients showed marked improvement in Harris hip score from preoperative mean 49.1 to 89.9 at 4 years or more follow-up. The complications include superficial infection (n = 2). No dislocation, or no osteolysis was seen in the pelvis or proximal femur, and no components failed due to aseptic loosening. There was no evidence of cup migration, screw breakage, or eccentric wear on the liner.ConclusionThe mid-term results in this series of patients with LDH using 36 mm femoral head articulating with highly cross linked polyethylene showed excellent clinical, and radiological results, in terms of, joint restoration that replicates the natural anatomy, optimized range of motion without impingement & reduced opportunity for postoperative dislocation.     

Dislocation after polyethylene liner exchange in total hip arthroplasty

Little has been published on the outcomes of polyethylene liner exchanges for wear or osteolysis. We assessed 24 patients from our clinic who had an isolated polyethylene liner exchange for wear or osteolysis with retention of the acetabular shell and femoral stem. At a mean 56-month follow-up time, 6 hips (25%) had dislocated. Of these, 2 underwent repeat surgery for recurrent dislocation; 1 had 3 dislocations; 1 had 2 dislocations; and 2 had single dislocations. Seventeen of the remaining patients answered our questionnaire: 13 recovered faster from the polyethylene liner exchange than from the primary arthroplasty; 4 believed that their hips were not as stable, 4 believed the hip did not function as well; and 1 underwent revision for cup loosening. We conclude that polyethylene liner exchanges, with or without femoral head exchange for wear or osteolysis, are associated with a high risk of dislocation and possible decrease in function.     

Catastrophic failure of ceramic-polyethylene bearing total hip arthroplasty

Complications of ceramic-polyethylene bearing total hip arthroplasty (THA) include osteolysis, loosening, dislocation, and component failure. Catastrophic acetabular component failure involves severe damage to both the polyethylene liner and metal shell. This case study presents the first reported complete wear-through of the acetabular portion of a ceramic-polyethylene arthroplasty presenting as a dislocation and a review of the literature. In this study, a patient's alumina ceramic femoral head penetrated the polyethylene liner and titanium shell and presented as a dislocated THA. The contributing factors for this catastrophic failure include young patient age, high activity level, thin polyethylene liner, backside wear, component positioning, polyethylene sterilization with gamma irradiation in air, and lack of appropriate follow-up. Revision THA was performed without complications.     

Cementation of a Dual Mobility Cup Into an Existing Well-Fixed Metal Shell: A Reliable Option to Manage Wear-Related Recurrent Dislocation in Patients With High Surgical Risk

BackgroundDuring revision total hip arthroplasty (THA), the “double-socket” technique has been proposed as a straightforward solution in order to reduce the overall perioperative morbidity in patients with high surgical risk. However, the option of cementing a dual mobility cup into an existing well-fixed metal shell was sparsely reported. Therefore, this study aimed to evaluate the outcome of a “double-socket” technique performed with a cemented dual mobility cup in revision THA for late instability.MethodsTwenty-eight revision THAs (28 patients) were performed for wear-related recurrent dislocation using a “double-socket” technique with a cemented dual mobility cup and retrospectively reviewed. The age at revision averaged 82 years (range 74-93). According to the American Society of Anesthesiologists (ASA) physical status classification, 12 patients (43%) were ASA II and 16 patients (57%) were ASA III before revision.ResultsAt a mean follow-up of 3.5 years (range 2-5), the mean preoperative to postoperative functional outcome improved significantly (P < .01). The mean operative time was 107 minutes (range 75-140). The mean intraoperative bleeding was 200 mL (range 110-420). No postoperative complication, reoperation, or re-revision was reported. Importantly, no dislocation, dissociation of the cemented dual mobility cup construct, or aseptic loosening of the retained metal shell was observed.ConclusionThe “double-socket” technique with a dual mobility cup cemented into an existing well-fixed and well-positioned metal shell ensured a straightforward and blood-sparing revision technique that was efficient to restore stability and provide a secure acetabular construct in frail patients with high surgical risk and/or older than their natural life expectancy.     

Cementation of a metal-inlay polyethylene liner into a stable metal shell in revision total hip arthroplasty

The purpose of this study was to evaluate the results of liner cementation into a stable acetabular shell using a metal-inlay polyethylene liner in 39 revision total hip arthroplasties. After an average of 2.8 years, 1 cemented liner dislodged from its metal shell at a postoperative 4 years. In the other 38 hips, mean Harris hip scores improved from 65 preoperatively to 86.9 at the final follow-up. Eighteen patients were rated as having excellent results, 17 as good, and 3 as fair. There were no changes in cup position and no cases of osteolytic lesion progression around the femoral and acetabular components in the last follow-up radiographs. Metal-inlay polyethylene liner cementation into a stable acetabular shell was found to provide an alternative option with short-term excellent results, and it also offers more liner options, the preservation of bone stock, and lower surgical morbidity.     

Dual mobility cup: dislocation rate and survivorship at ten years of follow-up

Purpose

The dual mobility cup introduced in France by Gilles Bousquet has been used in total hip replacement in high-risk patients. This device acts as a large ball implant and significantly reduces the risk of dislocation following hip arthroplasty. Published French literature has focused on low rates of dislocation and long-term follow-up similar to the low-friction arthroplasty.

Methods

We retrospectively reviewed a continuous series of 105 cases of dual mobility cup Quattro (Groupe Lépine, Genay, France) implanted from 2000 to 2002. Selection of the patients requiring a primary hip replacement depended on risk criteria such as age, hip disease and activity score. The dual mobility cup was associated with a modular cemented femoral component and a 22.2-mm stainless steel head.

Results

One dislocation occurred one month after the index surgery requiring no revision surgery. According to the Kaplan-Meier method, survival probability was 95.0 % (95 % confidence interval 81.5–98.8) at ten years of follow-up.

Conclusions

Based on clinical outcome and patient assessment we conclude that the dual mobility cup is a reliable option to decrease dislocation risk without increasing polyethylene wear.     

Cementless total hip arthroplasty and limb-length equalization in patients with unilateral Crowe type-IV hip dislocation

BACKGROUND: Total hip arthroplasty in patients with unilateral congenital high dislocation of the hip (Crowe type IV) presents many challenges, including the problem of a marked limb-length discrepancy. The purpose of this retrospective study was to analyze the results of total hip replacement with limb-length equalization in these patients. METHODS: From 1988 to 1996, fifty-six patients (forty-seven women and nine men) with unilateral Crowe type-IV dislocation of the hip were treated with a cementless total hip arthroplasty at a mean age of 35.4 years. The preoperative limb-length discrepancy averaged 4.9 cm. Prior to the total hip arthroplasty, forty-eight patients with a limb-length discrepancy of >4.0 cm underwent iliofemoral distraction with use of an external fixator for eight to seventeen days. The acetabular cup was placed in the anatomical position in every patient. Shortening femoral osteotomies were not required. RESULTS: The iliac fixator pins loosened in six patients. No patient had a pin-site infection, hip joint infection, or nerve palsy. At the time of follow-up, at an average of 147.2 months, the Harris hip score averaged 90.2 points. Overall, the mean lengthening after the total hip arthroplasty was 4.6 cm. There were no revisions of the femoral stem. Nine cups were revised, four because of polyethylene wear and five because of loosening. CONCLUSIONS: We were able to safely place the acetabular cup at the anatomical position without femoral shortening by bringing the femoral head to the normal level preoperatively; thus, we could restore nearly normal limb length. We believe that our twelve-year results are similar to those of total hip arthroplasty in patients without dysplasia.     

Fracture of a titanium sleeve-encased third-generation ceramic liner in a modern THA

Due to their excellent tribology, ceramics are increasingly used for total hip arthroplasty (THA) in young patients. Fracture rates for contemporary ceramics range from 0% to 0.004%. Recently, ceramic liners are encased in a titanium sleeve to further decrease the chances of fracture. We encountered 1 case of a metal-encased acetabular liner fracture in a ceramic-on-ceramic articulation in a series of 764 hips. Our literature review revealed no reports of metal-encased ceramic liner fracture. A 60-year-old woman presented 27 months after a bilateral ceramic-on-ceramic THA. She reported mechanical grinding and clicking from the left hip on extension. There was no history of trauma or fall. Examination revealed a nonantalgic gait and audible-palpable crepitations on the left hip. Range of motion of the left hip was intact with no subluxation. Radiographs revealed fractured ceramic insert and an excessively anteverted socket on the left side. Intraoperative findings revealed gross impingement in the form of indentation of the metal femoral neck against the elevated metal rim encasing the liner. Revision THA was performed using an uncemented polyethylene liner while retaining the well-fixed cup and stem. The Harris Hip Score at 4.5-year follow-up was 100, with no evidence of osteolysis or polyethylene wear.     

Cementation of Cross-linked Polyethylene Liner Into Well-Fixed Acetabular Shells : Mean 6-Year Follow-Up Study

The purpose of this study was to evaluate retrospectively the outcomes of cementation of cross-linked polyethylene (PE) liner in a well-fixed metal shell in 23 hips with an average follow-up period of 6 years. The mean Harris hip score was 69.6 ± 12 (range, 46-83) points preoperatively. The average postoperative follow-up was 72.3 months (range, 56-100 months). At the final follow-up, the mean Harris hip score was 95.5 ± 3 (84-100) points. There was no change in the bone-shell interface. No new osteolytic lesions were identified. The lesions impacted with bone graft had united completely. The remaining osteolytic lesions had decreased in size. There was no recurrent osteolysis, hip dislocation, component migration, and failure at the cement-metal interface. The results of the current study revealed that cementation of cross-linked PE liner into a well-fixed shell provided good midterm durability.     

The dual mobility poly liner: A worthwhile articulation choice?

Dual mobility liners represent an alternative to large heads to prevent dislocation. We used dual mobility in primary total hip arthroplasty in 2 patients (3 hips) with cerebral palsy; there were no dislocations or revisions at a mean follow-up of 2.3 years. In 22 patients (22 hips) revised to dual mobility, the most prevalent indication was adverse reaction to metal debris. There were 3 re-revisions at 1.8 years: 1 recurrent dislocation precipitated by traumatic injury, 1 deep infection and 1 unexplained pain. For abductor deficiency, a constrained liner may be indicated.     

Modern total hip arthroplasty in patients younger than 21 years

Total hip arthroplasty (THA) is not commonly performed in adolescents. However, it may be the only option for pain control with continued mobility for advanced disease. We report our experience with modern alternative-bearing THA in patients younger than 21 years. Twenty-one THAs (18 patients) were followed. Preoperative and postoperative Harris hip scores were recorded, and radiographs were reviewed. Average follow-up was 49 months (range, 25-89). Underlying etiology was chemotherapy-induced osteonecrosis (33%), steroid-induced osteonecrosis (29%), sickle cell disease (24%), and chronic dislocation (14%). Articulation bearings were ceramic/ceramic (67%), metal/highly cross-linked polyethylene (29%), and metal resurfacing (5%). Mean age was 18 years (range, 13-20). Harris hip scores improved from 43.6 to 83.6 (P < .001). At final follow-up, there was no radiographic loosening; 1 THA was revised for a cracked ceramic liner. At intermediate-term follow-up, clinical and radiographic results are favorable after alternative-bearing THA in patients younger than 21 years.     

Early failure of a polyethylene acetabular liner cemented into a metal cup

In 2002, a patient underwent revision total hip arthroplasty for polyethylene wear. The acetabular cup was well fixed, and it was decided to cement a new polyethylene liner into the existing cup. In 2006, the patient presented with inability to weight bear and easy subluxation of the hip. Revision surgery was performed, and all components were examined postoperatively. Investigation with microcomputed tomography revealed that the liner had plastically deformed at the superior pole resulting in the hip instability. The reasons for this are suspected to be related to the abducted nature of the original cup and an uneven cement mantle. This report suggests that cementation of polyethylene liners into metal cups has limitations and is not appropriate in all circumstances.     

Influence of component positions on dislocation: computed tomographic evaluations in a consecutive series of total hip arthroplasty

Component positions in a consecutive series of total hip arthroplasty through a posterolateral approach without capsular and external rotator repair, using the same prosthesis type, head size, and liner, were evaluated using computed tomography, and correlation with occurrence of postoperative dislocation was assessed. The 9 hips with posterior dislocation had significantly lower cup anteversion than the 181 hips without dislocation. Seven (78%) of the 9 hips with posterior dislocation had cup anteversion <20 degrees, irrespective of stem anteversion. These findings suggest that among variables of component positions, cup anteversion is one of the important factors for risk of dislocation, and that intentionally placing the cup at low anteversion to compensate for high femoral neck anteversion may predisposes the hip to postoperative dislocation.     

Unconstrained tripolar implants for primary total hip arthroplasty in patients at risk for dislocation

We performed a retrospective study on 167 primary total hip arthroplasty (THA) procedures in 163 patients at high risk for instability to assess the reliability of unconstrained tripolar implants (press-fit outer metal shell articulating a bipolar polyethylene component) in preventing dislocations. Eighty-four percent of the patients had at least 2 risk factors for dislocation. The mean follow-up length was 40.2 months. No dislocation was observed. Harris hip scores improved significantly. Six hips were revised, and no aseptic loosening of the cup was observed. The tripolar implant was extremely successful in achieving stability. However, because of the current lack of data documenting polyethylene wear at additional bearing, the routine use of tripolar implants in primary THA is discouraged and should be considered at the present time only for selected patients at high risk for dislocation and with limited activities.