Comparison of offset in Birmingham hip resurfacing and hybrid total hip arthroplasty

Hip resurfacing is being performed more frequently in the United Kingdom. The possible benefits include more accurate restoration of leg length, femoral offset and femoral anteversion than occurs after total hip arthroplasty (THA). We compared anteroposterior radiographs from 26 patients who had undergone hybrid THA (uncemented cup/cemented stem), with 28 who had undergone Birmingham Hip Resurfacing arthroplasty (BHR). We measured the femoral offset, femoral length, acetabular offset and acetabular height with reference to the normal contralateral hip. The data were analysed by paired t-tests. There was a significant reduction in femoral offset (p = 0.0004) and increase in length (p = 0.001) in the BHR group. In the THA group, there was a significant reduction in acetabular offset (p = 0.0003), but femoral offset and overall hip length were restored accurately. We conclude that hip resurfacing does not restore hip mechanics as accurately as THA.     

Changes in bone mineral density in the proximal femur after hip resurfacing and uncemented total hip replacement: A prospective randomised controlled study

We undertook a randomised prospective follow-up study of changes in peri-prosthetic bone mineral density (BMD) after hip resurfacing and compared them with the results after total hip replacement. A total of 59 patients were allocated to receive a hip resurfacing (n = 29) or an uncemented distally fixed total hip replacement (n = 30). The BMD was prospectively determined in four separate regions of interest of the femoral neck and in the calcar region corresponding to Gruen zone 7 for the hip resurfacing group and compared only to the calcar region in the total hip replacement group. Standardised measurements were performed pre-operatively and after three, six and 12 months. The groups were well matched in terms of gender distribution and mean age. The mean BMD in the calcar region increased after one year to 105.2% of baseline levels in the resurfaced group compared with a significant decrease to 82.1% in the total hip replacement group (p < 0.001) by 12 months. For the resurfaced group, there was a decrease in bone density in all four regions of the femoral neck at three months which did not reach statistical significance and was followed by recovery to baseline levels after 12 months. Hip resurfacing did indeed preserve BMD in the inferior femoral neck. In contrast, a decrease in the mean BMD in Gruen zone 7 followed uncemented distally fixed total hip replacement. Long term follow-up studies are necessary to see whether this benefit in preservation of BMD will be clinically relevant at future revision surgery.     

Radiographic comparison of cemented and uncemented total hip arthroplasty and hip resurfacing

Introduction The technology available for replacing/resurfacing the hip is constantly evolving. The surgeon can now choose from a wide array of components to perform a cemented, hybrid, uncemented total hip arthroplasty (THA) or resurfacing arthroplasty (RSA). The aim of our study was to evaluate and compare the restoration of hip biomechanics following the insertion of three different, commonly used constructs. Methods We compared the pre and postoperative radiographs from 40 patients who underwent cemented THA, 45 patients who underwent uncemented THA and 40 who underwent RSA. The femoral offset and limb length differences were measured, with reference to the normal contralateral hip. Results Resurfacing resulted in a significant reduction in femoral offset, with accurate restoration of limb length. Both cemented and uncemented THA resulted in a significant increase in femoral offset and leg length, uncemented THA’s resulted in the greatest degree of leg lengthening. Discussion Restoration of normal hip anatomy optimises biomechanical function and reduces wear of components. The RSA group had the most accurate restoration in comparison to the two other groups. The reduced femoral offset associated with the RSA group may reduce the lever arm of the abductor muscles however this is unlikely to be clinically significant.      

Femoral neck resorption following hybrid metal-on-metal hip resurfacing arthroplasty: a radiological and biomechanical analysis

Introduction  

With the resurgence of resurfacing hip arthroplasty complications such as femoral neck fracture and thinning have been identified. We therefore conducted a radiological and biomechanical evaluation of factors affecting femoral neck resorption following resurfacing hip arthroplasty (RHA).     

The femoral head/neck offset and hip resurfacing

Because the femoral head/neck junction is preserved in hip resurfacing, patients may be at greater risk of impingement, leading to abnormal wear patterns and pain. We assessed femoral head/neck offset in 63 hips undergoing metal-on-metal hip resurfacing and in 56 hips presenting with non-arthritic pain secondary to femoroacetabular impingement. Most hips undergoing resurfacing (57%; 36) had an offset ratio or= 50.5 degrees. Most hips undergoing resurfacing have an abnormal femoral head/neck offset, which is best assessed in the sagittal plane.     

Early Return to Function After Hip Resurfacing : Is It Better Than Contemporary Total Hip Arthroplasty?

Our hypothesis was that return of function for young patients undergoing resurfacing total hip arthroplasty (THA) with metal-on-metal bearings or contemporary THA with ceramic bearings would be comparable. Results from 337 unilateral hip resurfacing patients were compared with results from 266 unilateral ceramic-on-ceramic THA patients. Early differences in Harris Hip Scores were observed, but all differences faded by 24 months. Hip resurfacing seems to be a viable alternative to THA for well-selected patients. However, the public perception of improved functional capabilities was not demonstrated in this patient population. Resurfacing patients may be more impaired (slightly higher pain scores/lower function scores) than their THA counterparts in the early postoperative period, but these differences disappear by 24 months when both groups report Harris Hip Scores in the excellent range.     

Birmingham hip resurfacing arthroplasty: a series of 110 consecutive hips with a minimum five-year clinical and radiological follow-up

We report the outcome at a minimum of five years of 110 consecutive metal-on-metal Birmingham Hip Resurfacing arthroplasties in 98 patients. The procedures were performed between October 1999 and June 2002 by one surgeon. All patients were followed up clinically and radiologically. The mean follow-up was 71 months (60 to 93). Revision of either component was defined as failure. The mean Harris Hip score at follow-up was 96.4 (53 to 100). The mean Oxford hip score was 41.9 (16 to 57) pre-operatively and 15.4 (12 to 49) post-operatively (p < 0.001). The mean University of California Los Angeles activity score was 3.91 (1 to 10) pre-operatively and 7.5 (4 to 10) post-operatively (p < 0.001). There were four failures giving a survival at five years of 96.3% (95% confidence interval 92.8 to 99.8). When applying a new method to estimate narrowing of the femoral neck we identified a 10% thinning of the femoral neck in 16 hips (14.5%), but the relevance of this finding to the long-term outcome remains unclear. These good medium-term results from an independent centre confirm the original data from Birmingham.     

A new uncemented hydroxyapatite-coated femoral component for the treatment of femoral neck fractures: two-year radiostereometric and bone densitometric evaluation in 50 hips

Our aim in this pilot study was to evaluate the fixation of, the bone remodelling around, and the clinical outcome after surgery of a new, uncemented, fully hydroxyapatite-coated, collared and tapered femoral component, designed specifically for elderly patients with a fracture of the femoral neck. We enrolled 50 patients, of at least 70 years of age, with an acute displaced fracture of the femoral neck in this prospective single-series study. They received a total hip replacement using the new component and were followed up regularly for two years. Fixation was evaluated by radiostereometric analysis and bone remodelling by dual-energy x-ray absorptiometry. Hip function and the health-related quality of life were assessed using the Harris hip score and the EuroQol-5D. Up to six weeks post-operatively there was a mean subsidence of 0.2 mm (-2.1 to +0.5) and a retroversion of a mean of 1.2° (-8.2° to +1.5°). No component migrated after three months. The patients had a continuous loss of peri-prosthetic bone which amounted to a mean of 16% (-49% to +10%) at two years. The mean Harris hip score was 82 (51 to 100) after two years. The two-year results from this pilot study indicate that this new, uncemented femoral component can be used for elderly patients with osteoporotic fractures of the femoral neck.     

Comparison of Dislocation and Outcome Between Piriformis-Sparing and Conventional Posterior Approach After Bipolar Hemiarthroplasty for Femoral Neck Fracture in Patients Over 60 Years

BackgroundHemiarthroplasty is a treatment option for femoral neck fractures in patients aged more than 60 years and postoperative dislocation after a posterior approach is not uncommon. The piriformis tendon is one of the structures providing posterior hip stability. However, evidence of piriformis-sparing approach in hemiarthroplasty is unclear regarding a reduced dislocation rate.MethodsBetween January 2017 and December 2019, 321 patients underwent a posterior approach in consecutive cohorts for a hemiarthroplasty for femoral neck fractures with the minimum 24 months follow-up time (24-60 months). There were two cohorts: (1) 129 underwent the conventional posterior (CP) approach and (2) 192 underwent the piriformis-sparing (PS) approach. The differences in dislocation rate, postoperative Harris Hip Society at 1 and 2 years and other surgical complications were compared in both groups.ResultsThere were 6 dislocations of 129 (4.7%) underwent the CP approach and 0 dislocation from 192 underwent the PS approach that had posterior hip dislocations (P = .004). In addition, the CP group had a significantly higher mortality rate (14.7% versus 7.3%, P = .031) and lower functional outcomes as assessed by mean Harris Hip Scores at 1 year (73 versus 78, P = .005) and 2 years postoperatively (73 versus 80, P < .001) relative to the PS group.ConclusionPS hemiarthroplasty was associated with a lower dislocation and mortality rate. Moreover, this approach gained a superior early to the mid-term functional outcome than the conventional posterior approach in elderly femoral neck fractures.Level of EvidenceII, prospective cohort study.     

Uncemented primary press-fit total hip arthroplasty: a 3 to 6 years of experience

PURPOSE: To analyse the 3 to 6 years' clinicoradiological outcome of 45 uncemented total hip arthroplasties performed in 37 patients using cementless Spotorno stem and St Nabor cup. METHODS: The main indications for surgery were avascular necrosis of the femoral head and rheumatoid arthritis. Younger patients with good bone quality and a trumpet-shaped femur were eligible. A single surgeon performed all the operations using a posterolateral approach. Patients were reviewed at 6 weeks, 3 months, 6 months, and yearly thereafter. The clinical status was recorded using the Harris Hip Score. All radiographs were analysed by 2 independent blinded observers on 2 separate occasions. RESULTS: The mean follow-up period was 49 months and the mean Harris Hip Score at the latest follow-up was 94. Osseointegration in the form of trabeculae running from the endosteum to the prosthesis surface along with tropism of the calcar was evident in 73% of the hips. None of the remaining hips showed any continuous radio-opaque lines suggestive of a lack of bone ongrowth. Patients with endosteal condensation had better Harris Hip Scores. Intra-operative stability of the implants could fairly predict outcome. CONCLUSION: Initial clinicoradiological results of uncemented total hip arthroplasty are promising in younger patients with good bone quality and a trumpet-shaped femur.     

Painful impingement of the hip joint after total hip resurfacing: a report of two cases

Many patients undergoing total hip resurfacing arthroplasty present with reduced anterior femoral neck concavity as a part of the degenerative process. Painful hip impingement may develop or persist after hip resurfacing when the retained femoral neck abuts against the metallic acetabular component or the anterior acetabular bony wall. We report on two cases of painful postoperative hip impingement after hip resurfacing, in one of whom anterior neck-contouring osteoplasty restored pain-free range of motion (ROM). To restore natural hip ROM, surgeons performing hip total hip resurfacing arthroplasty should aim to reproduce the normal femoral head-neck offset ratio. Femoral head-neck offset restoration can be achieved by proper femoral component positioning (especially optimal translation), by femoral neck osteoplasty or by increasing femoral component head size appropriately.     

Conventional computed tomography software can be used for accurate pre-operative templating in bipolar hip arthroplasty: A preliminary report

BackgroundThe aim of this study was to investigate the use of pre-operative templating for bipolar hip arthroplasty (BHA) for displaced femoral neck fracture using multiplanar reconstruction (MPR) of computed tomography (CT) images.MethodsNineteen patients who underwent BHA were enrolled in this study. For pre- and post-operative evaluation, a CT scan was performed from the pelvis to the knee joints. MPR of the CT image was done using software to measure the femoral head cup diameter, offset, stem size, length of the modular neck, distance from the neck osteotomy, and femoral anteversion. We compared these parameters pre- and post-operatively.ResultsBoth the femoral head cup diameter and length of the modular neck were found to be significantly different between pre- and post-operative measurements, although the differences were minor. Other parameters, including the femoral offset, were not significantly different between the pre- and post-operative measurements. The size of the femoral stem, cup diameter, and length of the modular neck were consistent with the planned size and accurate (within ±1 size) in more than 84% cases.ConclusionOur pre-operative templating approach for BHA using MPR of CT has potential clinical utility as a complementary tool for pre-operative planning using three-dimensional templating software. Moreover, this technique could be feasible in most hospitals without additional expenditure.     

The Results of Metal-On-Metal Hip Resurfacing in Patients Under 30 Years of Age

Degenerative hip conditions most commonly affect older patients. However, many cases occur in younger patients. Total hip arthroplasty is the conventional approach; however, hip resurfacing is a viable option. Fifty-three metal-on-metal resurfacings in 46 patients under age 30 were performed. Patients had a variety of etiologies, and were followed clinically and radiographically with mean follow-up of 98.2 months. Clinical scores and x-rays were compared pre-operatively and post-operatively. The last follow-up SF-12 and UCLA scores significantly improved post-operatively (P < 0.0001). Range of motion scores also improved (P < 0.001), and the mean Harris Hip Score was 88. There were 6 revisions. The Kaplan–Meier survivorship estimate at 8 years was 95%. Metal-on-metal hip resurfacing appears to be an effective procedure for younger patients. Longer-term data are needed for confirmation.     

Resurfacing hip arthroplasty. A 3 to 5-year matched pair study of two different implant designs

We compared the 3 to 5 year clinical and radiological results of two different hybrid metal-on-metal resurfacing hip arthroplasty designs in 28 patients who had undergone bilateral hip resurfacing with ReCap implants on one side and BHR implants on the other side. Both hips were compared in each patient, to specifically evaluate the bone response to the cemented femoral component. Post operative function was measured with the Harris Hip Score and University of California at Los Angeles (UCLA) Activity Score, and was excellent in these patients. Mean cup inclination was 43.3 degrees +/- 7 degrees (43.3 degrees +/- 7 degrees for the BHR and 43.4 +/- 6 degrees for the Recap). The inclination angle was greater than 45 degrees in 15 patients: 7 with a BHR, 8 with a Recap; eight patients showed inclination angles greater than 50 degrees (4 patients in each group). All acetabular monoblock cups were well fixed. One patient (1.8%) had radiographs showing bone changes of uncertain significance around the stem of the femoral component. Three percent had femoral bone resorption in the BHR hip and two percent showed bone resorption in the ReCap hip. There was no evidence of migration of the femoral components. The dual energy X-ray absorptiometry (DEXA) scans identified no real reduction in bone density in these resurfacing hip arthroplasties. None of these hips showed any other adverse features. The biological response showed no difference for the two different designs of resurfacing hip arthroplasties.     

金属对金属全髋关节表面置换术早中期临床报告

目的探讨金属对金属全髋关节表面置换术治疗髋关节疾病的早中期临床效果,分析影响疗效的相关因素。方法回顾性分析我科全髋关节表面置换术患者54例60髋,男28例32髋,女26例28髋,年龄22～62岁,平均（42.3±12.5）岁。术后患者均进行定期临床与影像学随访16～45个月,平均随访32个月。采用Harris,UCLA,VAS评分对患者术前术后的髋关节功能进行评估。结果 Harris评分由术前38.3分增加到术后95.4分;UCLA评分由术前3.6分增加到术后7.9分;VAS评分由术前8.8分降低到术后1.8分。患者假体位置良好,无假体松动、关节脱位、股骨颈骨折及明显骨溶解等并发症。结论全髋关节表面置换术能有效改善髋关节疾病患者的关节功能、减轻疼痛,早中期随访结果满意。     

Spontaneous Recurrent Dislocation After Primary Birmingham Hip Resurfacing: A Rare Complication in a 44-Year-Old Man

Dislocation is a rare complication of hip resurfacing in young people. This is thought to be due to the stability imposed by a large-diameter head [Stulberg BN, Trier KK, Naughton M, et al. Results and Lessons Learned from a United States Hip Resurfacing Investigational Device Exemption Trial. J Bone Joint Surg Am 2008;90:21]. We report an isolated case 1 week post-Birmingham hip resurfacing in a 44-year-old man without any history of trauma or infection. We note that due to massive periacetabular and femoral neck osteophyte formation and loss of normal bony anatomical landmarks, the version of the acetabular component may have been slightly retroverted. Due to marked narrowing of the femoral neck and head proximally, a cone-shaped proximal femur was found and felt to be unsuitable for direct resurfacing without prior shortening to allow fitting of the appropriate-sized Birmingham hip resurfacing femoral component. This was done successfully, but resulted in slightly reduced femoral neck offset of approximately 10 mm, compared to the native hip. We suspect this reduced offset contributed significantly to the 2 dislocations. We recommend careful preoperative planning and case selection to avoid this complication in similar patients.     

Mild Coronal Stem Malalignment Does Not Negatively Impact Survivorship or Clinical Results in Uncemented Primary Total Hip Arthroplasties With Dual-Tapered Implants

BackgroundProper component positioning in total hip arthroplasty (THA) is crucial for implant fixation and hip stability. The purpose of this study is to assess if neutral coronal stem alignment (0° ± 3°) improved long-term survivorship in uncemented femoral components.MethodsBetween 2005 and 2010, 1028 primary THAs were performed with 2 contemporary dual-tapered, proximally coated uncemented stem types. Alignment was measured immediately postoperatively and at most recent follow-up. In total, 978 femoral stems (95%) were within 0° ± 3° of the neutral anatomic coronal axis, and the 50 stems (5%) outside that range were considered outliers (3.1° of valgus to 4.8° of varus). Outcomes analyzed included implant survivorship, Harris Hip Scores, and incidence of dislocation. Mean follow-up was 5 years.ResultsSurvivorship free of aseptic femoral component loosening was 99.3% and 98.2% at 5 and 8 years in the neutral group vs 100% at 5 and 8 years in the outlier group (P = .98). Survivorship free of femoral component revision for any reason was 99.1% and 97.3% at 5 and 8 years vs 100% at 5 and 8 years, respectively (P = .80). Harris Hip Scores were similar (89 in both groups; P = .84) at most recent follow-up. The incidence of mild to moderate thigh pain was also similar in both groups (6.1% vs 6%, P = .85). The incidence of dislocation was 1.5% at 8 years, and similar between both groups (P = .77).ConclusionSlight malalignment of contemporary dual-tapered uncemented THA femoral components does not appear to negatively impact survivorship or clinical outcomes, which is in contrast to cemented femoral components.Level of evidence IIICase-control study.     

Predictors of Femoral Neck Fracture Following Hip Resurfacing: A Cadaveric Study

We aimed to establish if radiological parameters, dual energy x-ray absorptiometry (DEXA) and quantitative CT (qCT) could predict the risk of sustaining a femoral neck fracture following hip resurfacing. Twenty-one unilateral fresh frozen femurs were used. Each femur had a plain digital anteroposterior radiograph, DEXA scan and qCT scan. Femurs were then prepared for a Birmingham Hip Resurfacing femoral component and loaded to failure. Results demonstrated that gender and qCT measurements showed strong correlation with failure load. QCT could be used as an individual measure to predict risk of post-operative femoral neck fracture. However, when qCT is unavailable; gender, pre-operative DEXA scan and Neck Width measurements can be used together to assess risk of post-operative femoral neck fracture in patients due to undergo hip resurfacing.     

The Bicontact cementless primary total hip arthroplasty: long-term results

We report on a prospective series of 201 primary uncemented total hip arthroplasties with a Bicontact prosthesis at a mean follow-up of 12.9 years. The mean Harris hip score improved from 41 before surgery to 89 at final follow-up. Two femoral stems, one each for infection and fracture, and 12 cups were revised. The mean number of years to revision post-primary surgery was 8.7 years (six months to 16 years). The cumulative survival of the prosthesis was 95.42% for any cause at ten years and 93.57% at 12 years. Survivorship for aseptic loosening of the femoral stem was 100%. In our series, the Bicontact uncemented total hip arthroplasty stem without hydroxyapatite coating showed excellent survival and the cup survival was comparable to other leading series.     

髋臼骨折内固定失败术后的全髋关节置换术

目的:探讨髋臼骨折内固定失败术后继发创伤性关节炎和(或)股骨头缺血性坏死行全髋关节置换术的特点及临床疗效。方法:2009年2月至2014年10月,采用全髋关节置换术对31例(31髋)髋臼骨折内固定失败继发创伤性关节炎和(或)股骨头缺血性坏死患者进行治疗,其中男26例,女5例;受伤时平均年龄(41±12)岁。患者因髋臼骨折内固定术后3~132个月,平均(20.6±26.9)个月内继发创伤性关节炎和(或)股骨头缺血性坏死而行全髋关节置换术,全髋关节置换术均采用后外侧入路。观察术后并发症和关节活动度,并比较术前和术后随访时髋关节VAS疼痛评分和Harris髋关节评分。结果:术后27例获得随访,随访时间12~80个月,平均(43.2±11.7)个月。其中出现关节感染1例,假体松动1例,脱位1例,无继发坐骨神经损伤病例发生。所有随访病例髋关节功能和步态有明显改善;至末次随访时,VAS由术前平均(7.6±1.2)分,降低到术后平均(1.2±0.9)分,Harris评分由术前平均(45.5±13.6)分,提高到术后平均(88.5±7.8)分,差异均有统计学意义(P0.01)。髋关节除后伸外,前屈、外展、内收、内旋及外旋活动范围较术前显著增加,差异有统计学意义(P0.05)。X线片复查示:髋臼假体无不稳定发生,1例股骨柄假体下沉3 mm,2例发生异位骨化。结论:正确处理内固定物,提防潜在感染,合理重建髋臼骨缺损,是髋臼骨折内固定失败术后全髋关节置换成功的关键。