Computer-assisted fluoroscopic navigation system for removal of distal femoral bone cement in revision total hip arthroplasty

Removal of the femoral bone cement in revision total hip arthroplasty with a high-powered drill or burr potentially has a risk of damage to the bone, resulting in perforation and fracture of the femur. Recently, we have used a computer-assisted fluoroscopic navigation system for the revision of cemented total hip arthroplasty with a high-powered burr and completely removed the distal femoral bone cement with no complications in 6 cases. Thus, a computer-assisted fluoroscopic navigation system is a useful tool for the improvement of the surgical technique in revision total hip arthroplasty.     

股骨皮质骨开窗技术在髋关节翻修术中的应用

目的 探讨股骨前外侧皮质骨开窗技术在髋关节翻修术中取出股骨远端稳定固定骨水泥的价值.方法 2005年5月至2009年6月,共14例(14髋)因各种原因致髋关节置换术后失败患者接受全髋关节翻修手术.其中男性10例,女性4例,年龄54～75岁,平均66岁.翻修原因为股骨头置换术后髋臼磨损5例、全髋关节置换术后假体周围骨溶解并松动6例、骨水泥柄股骨近端骨溶解柄断裂1例、髋臼骨溶解假体松动翻修同时行股骨柄翻修1例,感染后二期翻修时远端骨水泥取出困难1例.14例(14髋)股骨柄均为骨水泥同定.术中按术前计划开窗部位、开窗范围于股骨皮质骨开一长方形骨窗.通过骨窗直视下彻底清除髓腔内稳定固定的骨水泥,修整股骨髓腔.植入翻修柄后将皮质骨开窗骨瓣原位回植,双股钢丝捆绑固定.术后定期随访拍摄x线片.观察皮质骨开窗骨瓣与周围骨愈合情况、骨瓣有无移位、股骨柄有无下沉以及有无捆绑钢丝断裂等.结果 10例患者术后获得随访,平均随访时间24.6个月.股骨皮质骨开窗长度2.5～6.0 cm,平均3.4 cm,宽度0.8～1.4 cm,平均1.2 cm.股骨开窗远端以远部分发生纵形劈裂骨折1例.无术中皮质骨穿孔及股骨干骨折.向远段扩大开窗1例,扩大长度1.5 cm.开窗部位皮质骨骨瓣原位回植选择2～3道双股钢丝固定,平均2.3道.随访期间2例发牛假体柄下沉(平均2.5 mm),无皮质骨瓣移位以及捆绑钢丝断裂,术后3～5个月皮质骨瓣已于周围骨纤维愈合.随访期间无一例因各种原因致再次翻修.结论 股骨皮质骨开窗技术在髋关节翻修术中有助于直视下彻底取出股骨髓腔远端稳定固定的骨水泥,同时不会造成股骨骨丢失、不影响翻修柄植入后的稳定固定.     

Total hip arthroplasty cemented femoral component distal stem centralizer: Effect on stem centralization and cement mantle

The effectiveness, benefits, and potential risks of employing a total hip arthroplasty cemented femoral component distal centralizer were evaluated. First postoperative (6-week) radiographs of 100 primary hybrid total hip arthroplastics in consecutive groups of 50 patients without and 50 patients with a femoeral stem distal centralizer were retrospectively reviewed. Femoral stems with a distal centralizer were more centralized within the femoral canal (center of stem tip to center of intramedullary canal: mean, 1.1 mm with a centralizer, 3.2 mm without; P < .0001) and more neutrally aligned (mean, 0.7° valgus with a centralizer, 1.3° valgus without; P < .01). Femoral stems with a distal centralizer were less likely to have a cement mantle with suboptimal thickness, that is, less than 2 mm at the medial distal femoral stem (3 of 50 stems with a centralizer, 22 of 50 stems without; chi-square, P < .0001). There were no complications, adverse effects on the cement mantle, radiographic evidence of loosening, or implant failures associated with the use of a distal centralizer, with a minimum follow-up period of 2 years.     

Femoral cement removal in revision total hip arthroplasty. A biomechanical analysis

A technique of femoral cement removal in revision total hip arthroplasty is described and biomechanically evaluated. Two 9-mm holes are drilled anteriorly through the proximal femoral cortex before cement is removed. These holes permit direct visualization of the medullary canal and help to prevent eccentric reaming or inadvertent perforation with the power drill. They also provide portals for enhanced irrigation, illumination, and cement removal. For assessment of the effect of cortical perforations on bone strength, 12 cadaveric femurs containing cemented prosthetic stems were analyzed. The femurs were stressed at various loads on the Instron Materials Testing Machine (Instro Engineering Corporation, Kenton, MA) under conditions simulating single-limb stance. The stress concentrations were significantly higher about laterally drilled holes than about those located anteriorly. When loaded to failure, all fractures occurred at or below the prosthetic stem tip. No fractures occurred in the proximally placed drill holes. A finite element model showed that two holes kept at least two hole diameters apart did not cause cumulative stress concentration.     

Distal cement mantle thickness with a triangular distal centralizer inserted into the stem tip in cemented total hip arthroplasty

Fifty-seven hips undergoing a primary cemented total hip arthroplasty with use of a triangular distal centralizer inserted into the stem tip were investigated, with a special focus on distal cement mantle thickness. The subjects were 43 women and 3 men. When evaluated on conventional anteroposterior and lateral radiographs, the relative incidence of thin cement mantles in zones 3 or 5 owing to the distal centralizer was 15.8% (9 hips). Unsatisfactory findings were that the distal centralizer and distal part of the stem shifted to the cortex in 7 hips and bent or failed at the inserted site in 2 hips. There is risk of generating a thin cement mantle with use of the triangular centralizer and its insertion into the stem tip.     

Histological findings of the femoral bone after cement removal in hip revision

Cement removal in hip revision arthroplasty is often a time-consuming procedure, lengthy and tedious. Intraoperative bone damage is one of the more common complications. In the present study, the conventional cement removal method is compared with a new method by means of a histological study concerning potential negative effects to cortical or spongious bone. Histological studies on human cadaver femurs demonstrate no deleterious effects on the endosteal bone when cement was removed with this new device. The ballistically driven chiselling system (OrthoClast) is safe to the bone stock and shows no increased risk of bone damage over the conventional technique with mallet and chisel.     

A stem-allograft composite for femoral revision in total hip arthroplasty

Femoral revision is difficult when the femoral canal exceeds 20 mm in diameter. For this subset of patients, we used a technique of cementing cortical allograft sleeves to a proximal ingrowth stem. The diameter of the allograft sleeves are matched to the diameter of the host femur. The stem-allograft construct provides initial stability with the opportunity for proximal bone ingrowth.     

Technique for a composite femoral intramedullary plug in cemented hip arthroplasty

A brief technique to place a cement plug on top of a polyethylene is presented. This technique has helped the authors obtain better cement mantles when they are plugging the canal in total hip replacement.     

Contamination during removal of cement in revision hip arthroplasty. A cadaver study using ultrasound and high-speed cutters

Instruments used in surgery which rotate or vibrate at a high frequency can produce potentially contaminated aerosols. Such tools are in use in cemented hip revision arthroplasties. We aimed to measure the extent of the environmental and body contamination caused by an ultrasound device and a high-speed cutter. On a human cadaver we carried out a complete surgical procedure including draping and simulated blood flow contaminated with Staphylococcus aureus (ATCC 12600). After cemented total hip arthroplasty, we undertook repeated extractions of cement using either an ultrasound device or a high-speed cutter. Surveillance cultures detected any environmental and body contamination of the surgical team. Environmental contamination was present in an area of 6 x 8 m for both devices. The concentration of contamination was lower for the ultrasound device. Both the ultrasound and the high-speed cutter contaminated all members of the surgical team. The devices tested produced aerosols which covered the whole operating theatre and all personnel present during the procedure. In contaminated and infected patients, infectious agents may be present in these aerosols. We therefore recommend the introduction of effective measures to control infection and thorough disinfection of the operating theatre after such procedures.     

Results of uncemented distal locked prosthesis in revision hip arthroplasty with proximal femoral bone loss: A retrospective study

Introduction:

Management of bone loss is a challenge in revision total hip arthroplasty (THA). A retrospective review was performed to study the use of uncemented distal locked prosthesis in cases with proximal femoral bone loss.

Materials and Methods:

Uncemented stems with distal interlocking were used in 65 hips during revision THAs with 38 hips having Paprosky IIIB/IV defects between January 1998 and February 2004. There were 48 males and 17 females in the study with an average age of 53 years (range 30-80 years). Radiographic and clinical outcome evaluation using the Harris hip score (HHS) were performed.

Results:

An improvement in HHS (mean: 33 points) was observed at final followup (mean: 9 years). Regeneration of proximal bone stock was observed without signs of loosening or subsidence and none of the stems were revised. Three patients developed recurrent dislocation while one had a stem subsidence of 1cm following removal of interlocking bolts.

Conclusion:

Uncemented distal locked prosthesis provide adequate stability in revision THA, aiding the reconstruction of bony deficiencies while avoiding the disadvantages of fully porous or cemented implants.     

Posterior distal cement extrusion during primary total hip arthroplasty: a cause for concern?

Manually operated injection systems are routinely used to deliver polymethyl methacrylate during cemented femoral component primary total hip arthroplasty (THA). The goal of cement delivery is to achieve sufficient intrusion of cement into the trabecular bone of the prepared femur so that the femoral component is securely bonded to the femur. We have observed posterior distal cement extrusion (PDCE), which appears to be secondary to too-successful pressurization. We sought to quantify and offer a possible explanation for this phenomenon. Eight patients with PDCE were identified, with an estimated incidence range of 0.90%, to 1.6% of primary cemented femoral component THA. All occurred in female patients of small stature. Endosteal canal diameters were also small, averaging 11 mm, 10 cm from the lesser trochanter. The PDCE occurred at an average distance of 9.8 cm from the midpoint of the lesser trochanter, and was most easily visualized on the lateral radiograph where it resided in the posterior soft tissues. Examination of 49 human femora showed 1 or more vascular channels in the posterior aspect of the femur in all specimens. The most proximal vascular channel averaged 10.1 cm distal to the lesser trochanter and had an average lumen diameter of 1 mm. The vascular channel contained an artery and 2 veins by histologic examination. We postulate that PDCE represents the escape of low-viscosity cement out of the vascular channel, and laboratory simulation supports this possibility. Because this finding has not previously been reported, we hoped that other centers will look closely for this phenomenon.     

Successful femoral reconstruction with a fluted and tapered modular distal fixation stem in revision total hip arthroplasty

Background and Aims: Early results of fluted and tapered distal fixation stems used in reconstruction of deficient femora in femoral revision arthroplasty have been successful in small series. We evaluated the survival of the LINK MP Reconstruction Hip Stem and factors associated with survival using data from a nation-wide arthroplasty register. Materials and Methods: 408 femoral revisions using LINK MP Reconstruction Hip Stem were performed during 1994 to 2007. The mean age of the patients was 72.5 (range: 36-93) years and 63% were performed in women. Kaplan-Meier analysis and the Cox regression model were used for the survival analysis. The effects of age, sex and diagnoses were also studied. Results: The 9-year overall survivorship for the LINK MP Reconstruction Hip Stem was 75% (95% CI 70-80). Aseptic loosening was rare; the 9-year revision rate for aseptic loosening was only 3%, which coincides with earlier reports with shorter folllow-up. The most common reason for re-revision was dislocation of the prosthesis with or without malposition of the socket (67%). Indication for revision strongly affected the survival rate with revisions for dislocation having an over 3-fold and revisions for infection a 3-fold relative risk for re-revision compared to revisions for aseptic loosening. Increasing age slightly decreased the risk of re-revision but sex did not affect the survival. Discussion: Based on our findings, we conclude LINK MP Reconstruction Hip Stem, as an example of a fluted and tapered distal fixation stem, appears to solve many problems with implant fixation in femoral revisions. High number of dislocations suggests that special attention should be paid to correct center of rotation, to correct implant positioning and to need of constrained implants in case of deficient abductor mechanism.     

远端固定型假体结合同种异体骨移植在髋关节股骨翻修中的应用

[目的]探讨应用远端固定生物型假体结合同种异体骨移植进行髋关节股骨侧翻修的临床效果。[方法]2008年7月~2014年5月,行非感染性假体松动股骨侧翻修11例(骨水泥假体10例,非骨水泥假体1例)。所有患者采用远端固定生物型假体结合股骨近端同种异体颗粒骨打压植骨,其中7例同时应用同种异体皮质骨支撑植骨。男4例,女7例;平均年龄65.3岁(48~79岁);左侧7例,右侧4例。初次置换原因:股骨头无菌性坏死6例,股骨颈骨折3例,骨性关节炎2例。翻修距原手术时间平均12.8年(3~21年)。依据Paprosky分型,Ⅱ型4例,ⅢA型4例,ⅢB型3例。临床功能评价采用Harris评分。翻修用假体:Restoration(Stryker)3髋,MP(Link)8髋。[结果]所有患者均获得随访,随防时间12~75个月,平均29个月。1例术后出现切口渗液,15d后愈合;1例术后6年并发假体周围螺旋形骨折(Vancouver分型B1),假体未松动,行切开复位内固定术。随访期内X线片显示移植骨均愈合良好,假体稳固,周围未见透亮带及松动、下沉征象;术前6例双下肢不等长患者均得到矫正(长度差1 cm);无感染、脱位及深静脉血栓形成等并发症;无假体再翻修病例。Harris评分从术前的平均(30.3±7.2)分提高到最后评估时的平均(82.4±5.9)分,Harris评分优良率为81.8%。[结论]在伴有广泛骨质缺失的股骨翻修中,远端固定生物型假体是较好的选择。术中采用股骨近端颗粒骨打压植骨重建干骺端骨缺损,并在股骨干部皮质薄弱或缺损时结合同种异体皮质骨支撑植骨,可使假体柄远近段均获得较好的初始稳定性,且中短期临床效果满意,远期疗效尚有待观察。     

Pelvic reconstruction with a free vascularized distal femur for revision total hip arthroplasty

The reconstruction of massive structural acetabular defects after revision arthroplasty presents a unique challenge to the orthopedic surgeon. This report describes such a salvage procedure where an autologous vascularized distal femur was used to reconstruct acetabular bone stock with subsequent implantation of a total femoral endoprosthetic replacement that uses a constrained cup and a hinged total knee system. At 2 years of follow-up, there is a good functional result with full incorporation of the graft.     

Use of an 'internal proximal femoral replacement' with distal fixation in revision arthroplasty of the hip

We have managed 27 patients (16 women and 11 men) with a mean age of 68.4 years (50 to 84), with failed total hip replacement and severe proximal femoral bone loss by revision using a distal fix/proximal wrap prosthesis. The mean follow-up was for 55.3 months (25 to 126). The mean number of previous operations was 2.2 (1 to 4). The mean Oxford hip score decreased from 46.2 (38 to 60) to 28.5 (17 to 42) (paired t-test, p < 0.001) and the mean Harris Hip score increased from 30.4 (3 to 57.7) to 71.7 (44 to 99.7) (paired t-test, p < 0.001). There were two dislocations, and in three patients we failed to eradicate previous infection. None required revision of the femoral stem. This technique allows instant distal fixation while promoting biological integration and restoration of bone stock. In the short term, the functional outcome is encouraging and the complication rates acceptable in this difficult group of patients.