Tissue Sparing Surgery and Its Relevance within Hip Prosthesis

The total hip replacement rationale, since 1960 when it was introduced by Sir Charnley, has been modified and evolved until nowadays thanks to laboratory research and clinical trials. This evolution followed a guideline whose milestones are: 1) the surgical approach and implantation technique (ex: detachment of the greater trochanter);2) to use or not to use cement;3) the evolution of materials (titanium, ceramic, x-linked polyethylene);4) the identification of the debris-disease rather than the cement-disease;5) studies focused on bone-prosthesis interaction and biological phenomena related. Between those studies, the authors consider crucial the introduction of tissue sparing surgery and femoral neck preserving rationale, concepts to which they have devoted their scientific research and clinical experience for over the last 30 years, from 1980 to nowadays.

Can periprosthetic hip joint infections be successfully managed by debridement and prosthesis retention?

To evaluate the current literature about how successfully periprosthetic hip joint infections can be managed by debridement and prosthesis retention.A literature search was performed through Pub Med until September 2013.Search terms were"DAIR(debridement,antibiotics,irrigation,and retention)"alone and in combination with"hip"as well as"hip infection+prosthesis retention".A total of 11 studies reporting on 292 cases could be identified.Five different treatment modalities have been described with varying success rates(debridement-21%infection eradication rate;debridement+lavage-75%infection eradication rate;debridement,lavage,with change of modular prosthesis components-70.4%infection eradication rate;debridement,lavage,change of modular prosthesis components+vacuum-assisted closure-92.8%infection eradication rate;acetabular cup removal+spacer head onto retained stem-89.6%infection eradication rate).With regard to the postoperative antibiotic therapy,no general consensus could be drawn from the available data.Debridement,antibiotic therapy,irrigation,and prosthesis retention is an acceptable solution in the management of early and acute hematogenous periprosthetic hip joint infections.The current literature does not allow for generalization of conclusions with regard to thebest treatment modality.A large,multi-center study is required for identification of the optimal treatment of these infections.

Correlation analysis between the interface membrane and loose hip prosthesis

Objective To analyze the cause of prosthesis loosening by observing the interface membranes harvested during the hip restoration operation. Methods A total of 28 specimens of interface membrane around the loose prosthesis were harvested from 28 patients undergoing the restoration of total hip replacement. All the specimens underwent the observation of appearance, light microscopy and scanning electronic microscopy(SEM). Results All the gaps around the loose prosthesis were filled with interface membrane of different thickness. The color of the most interface membrane was madder red, and the other one third of membrane was black. The comparatively thicker membrane was similar to scar connective tissue while the thinner was similar to fiber membrane. A large number of wear debris, macrophages and foreign-body giant cells were found under light microscope. With SEM observation a large number of different diameter collagen fibra structures that looked like scar tissues were arranged disorderly in a great mass, foreign particles and bone debris of different size were distributed unevenly, and the fibroblast was distributed in the collagen fiber. Conclusion Wear debris is related to inflammatory cell response around the interface membrane of the loose prosthesis. The wear debris engulfed by macrophage stimulates the interface membrane to release bone resorption factors (such as TNF) which lead to osteolysis, and this is one of the most important causes of the prosthesis loosening.

Total hip revision with custom-made spacer and prosthesis:A case report

BACKGROUND Both periprosthetic joint infections(PJIs)and severe femoral segmental defects are catastrophic complications of total hip arthroplasty(THA),and both present a significant challenge in revisional surgery.There are limited data available to guide clinical decision making when both occur concurrently.CASE SUMMARY A 61-year-old woman presented with a 6-mo history of a sinus tract at the site of her original THA incision.Radiological imaging revealed a total hip joint implant with an ipsilateral segmental femoral defect.Based on histological,radiological,laboratory,and clinical features,a diagnosis of concurrent chronic PJI and segmental femoral defect(Type IIIB,Paprosky classification)was made.After multidisciplinary team discussion,three-dimensional(3D)-printed,custom-made antibiotic spacers were created that could be used to mold antibiotic-loaded cement spacer.These were placed following PJI debridement in the first stage of revision surgery.After the PJI was eliminated,a 3D-printed,custom-made,femoral prosthesis was created to repair the considerable femoral defect.After 20-mo follow-up,the patient had excellent functional outcomes with a near-normal range of hip movement.So far,neither evidence of recurrent infection nor loosening of the prosthesis has been observed.CONCLUSION We describe a case of“two-stage,custom-made”total hip revision to treat PJI with a concurrent segmental femoral defect.Use of a personalized,3D-printed spacer and proximal femoral prosthesis led to satisfactory hip function and no early postoperative complications.Use of a customized implant provides surgeons with an alternative option for patients where no suitable spacer or implant is available.However,the long-term function,longevity,and cost-effectiveness of the use of custom-made prostheses have yet to be fully explored.

Which approach of total hip arthroplasty is the best efficacy and least complication?

BACKGROUND Total hip arthroplasty is as an effective intervention to relieve pain and improve hip function.Approaches of the hip have been exhaustively explored about pros and cons.The efficacy and the complications of hip approaches remains inconclusive.This study conducted an umbrella review to systematically appraise previous meta-analysis(MAs)including conventional posterior approach(PA),and minimally invasive surgeries as the lateral approach(LA),direct anterior approach(DAA),2-incisions method,mini-lateral approach and the newest technique direct superior approach(DSA)or supercapsular percutaneouslyassisted total hip(SuperPath).AIM To compare the efficacy and complications of hip approaches that have been published in all MAs and randomized controlled trials(RCTs).METHODS MAs were identified from MEDLINE and Scopus from inception until 2023.RCTs were then updated from the latest MA to September 2023.This study included studies which compared hip approaches and reported at least one outcome such as Harris Hip Score(HHS),dislocation,intra-operative fracture,wound compliData were independently selected,extracted and assessed by two reviewers.Network MA and cluster rank and surface under the cumulative ranking curve(SUCRA)were estimated for treatment efficacy and safety.RESULTS Finally,twenty-eight MAs(40 RCTs),and 13 RCTs were retrieved.In total 47 RCTs were included for reanalysis.The results of corrected covered area showed high degree(13.80%).Among 47 RCTs,most of the studies were low risk of bias in part of random process and outcome reporting,while other domains were medium to high risk of bias.DAA significantly provided higher HHS at three months than PA[pooled unstandardized mean difference(USMD):3.49,95%confidence interval(CI):0.98,6.00 with SUCRA:85.9],followed by DSA/SuperPath(USMD:1.57,95%CI:-1.55,4.69 with SUCRA:57.6).All approaches had indifferent dislocation and intraoperative fracture rates.SUCRA comparing early functional outcome and composite complications(dislocation,intra-operative fracture,wound complication,and nerve injury)found DAA was the best approach followed by DSA/SuperPath.CONCLUSION DSA/SuperPath had better earlier functional outcome than PA,but still could not overcome the result of DAA.This technique might be the other preferred option with acceptable complications.

DEVELOPED IMPROVED AND CLINICAL APPLICATION OF BIPOLAR HIP PROSTHESIS—2—13 YEARS FOLLOW—UP

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Causes and management of prosthesis dislocation after artificial hip replacement

Objective To explore the causes and management of prosthesis disocation after artificaial hip replacement (AHR).Methods Seventeen patients with prosthesis dislocation after AHR during January 2000 to July 2010 were studied

Long-term results of an anatomically implanted hip arthroplasty with a short stem prosthesis (MiniHip^(TM))

AIM To evaluate the clinical and radiological outcome nineand ten years after short-stemmed, bone preserving and anatomical hip arthroplasty with the MiniHip^(TM) system. METHODS In a prospective study, 186 patients underwent hip arthroplasty with a partial neck preserving short stem(MiniHip^(TM), Corin). Elderly patients were not excluded from this study, thus the mean age at the time of surgery was 59.3 years(range 32 to 82 years). Surgery and the follow-up assessments were performed at two Centers. Up until now, the mean follow-up was 112.5 ± 8.2 mo. The Oxford Hip Score(OHS) and the Hip Dysfunction Osteoarthritis and Outcome Score(HOOS) was assessed pre-and each year after surgery. The clinical follow-up was accompanied by standardized a.p. and axial radiological examinations. Periprosthetic lucencies, hypertrophies within the Gruen zones one to fourteen were assessed. A subsidence of the stem was investigated according to Morray and heterotopic ossifications were assessed according to Brooker.RESULTS The OHS and HOOS improved from 18 ± 3.3 to 46 ± 2.0 and from 30 ± 8.3 to 95 ± 4.6 points, P < 0.001 respectively. There were no differences regarding age, etiology, friction pairings, etc.,(P > 0.05). Two stems were revised due to a symptomatic subsidence four and twelve months postoperatively. Thus, the survivorship for aseptic loosening at nine to ten years was 98.66%. Including one stem revision due to a symptomatic exostosis, bursitis and thigh pain as well as one revision because of a septic stem loosening, the overall survival for the stem with revision for any reason was 97.32%. Besides one asymptomatic patient, radiological signs of a proximal stress-shielding, such as bone resorptions within the proximal Gruen zones, were not noticed. Findings suggesting a distal loading, e.g., bony hypertrophies or bone appositions of more than 2 mm, were also not detected. CONCLUSION Regarding these first long-term results on the MiniHip^(TM), the implant performed exceedingly well with a high rate of survivorship for aseptic loosening. Our radiological results within the Gruen zones support the design rationale of the Minihip to provide a reliable metaphyseal anchoring with the expected proximal, more physiological load transfer. This might minimize or exclude a stress shielding which might be associated with thigh pain, proximal bone loss and an increased risk of aseptic loosening. The MiniHip^(TM) is a reliable partial-neck retaining prosthesis with good a clinical long-term outcome in younger as well as elderly patients.

Total Hip Prosthesis in Dakar and Forensic Implication

The total hip prosthesis is the ultimate treatment of the hip joint’s wear. It is a delicate surgery and the most common replacements. This study was performed in the Orthopaedic-Traumatology Department of Public Health Establishment of Aristide Le Dantec in Dakar. It aimed to determine the complications of our total hip and highlight their forensic implications. This is a retrospective study from patients collected from January 2000 up to December 2010. The collection of elements records was performed for each patient, based on a file including age, sex, primary-location’s etiology, and types of complications of total hip prostheses. The analysis of these complications has shown that infections, poorly lit information, poor operational planning and technical foul may be the main cause of a forensic implication. This is a retrospective study from patients collected from January 2000 up to December 2010. No lawsuit has been recorded for the complications identified in this work. This is due to the belief in fate, ignorance of the victims and solidarity of the medical profession, the high cost and slow pace of judicial proceedings. The diagnosis of total hip prosthesis complications is mainly based on imaging tests. The absence of scintigraphy in our center remains a limit to the early diagnosis of multiple complications and the proper establishment of the epidemiological profile of these lesions. Taking consciences patients of their rights encourages a legitimate requirement repair the harm inflicted.

Roles of combined femoral and acetabular anteversion in pathological changes of hip dysplasia and hip reconstructive surgery

Combined femoral and acetabular anteversion is the sum of femoral and acetabular anteversion,representing their morphological relationship in the axial plane.Along with the increasing understanding of hip dysplasia in recent years,numerous scholars have confirmed the role of combined femoral and acetabular anteversion in the pathological changes of hip dysplasia.At present,the reconstructive surgery for hip dysplasia includes total hip replacement and redirectional hip preservation surgery.As an important surgery index,combined femoral and acetabular anteversion have a crucial role in these surgeries.Herein,we discuss the role of combined femoral and acetabular anteversion in pathological changes of hip dysplasia,total hip replacement,and redirectional hip preservation surgery.

Primary Total Hip Arthroplasty on Complex Hips Conditions in a Low-Resource Setting

Introduction: Total hip arthroplasty of complex morphology is a challenge for the orthopaedic surgeon. Careful analysis of the hip’s anatomy helps to unravel the difficulties and anticipate the procedures to be performed and the implants to be planned. The aim was to identify the types of hip that make first-line THR difficult, specify the technical procedures to be used on these sites, and assess the functional results of the series. Material and Methods: This was a retrospective study that concerned patients operated on for total hip arthroplasty between January 2015 and December 2022 at the medical center “La Grâce” in Bobo-Dioulasso, Burkina Faso. Patients with coxarthrosis (on hip dysplasia, acetabular protrusio, acetabular malunion or neurological hip) and those with ankylosis of the hip, osteonecrosis secondary to neglected dislocation of the hip or hemoglobinopathy were included. Results: A total of 31 total hip replacements were performed in 30 patients. The mean age of patients at the surgery time was 36.2 years with extremes of 17 and 61 years. The male-to-female sex ratio was 1. The main indications for THA were the dysplasic hip osteoarthritis (11 cases) and the neglected hip dislocations (7 cases). In situ femoral neck osteotomy before hip dislocation was performed in seven cases. The acetabulum reconstruction techniques varied from the structural iliac bone graft (n = 3) and cancellous bone graft (n = 4) to the Kerboull plate (n = 1). After 45 months of mean follow-up, all hips were evaluated. The mean PMA score increased from 7.1 [4 - 8] before the surgery to 13.2 [13 - 17]. Conclusion: The large spectrum of challenges in complex hip management requires effective preoperative planning. Preoperative planning minimizes complications and ensures a better outcome.

Examining the“revisability”benefit of hip resurfacing arthroplasty

BACKGROUND Hip resurfacing arthroplasty(HRA)is an alternative to total hip arthroplasty(THA)that is typically reserved for young active patients because it preserves bone.However,the benefits of HRA only hold true if conversion THA after failed HRA provides acceptable outcomes.AIM To compare patient reported outcomes for conversion THA after HRA failure to primary THA.METHODS A retrospective review of 36 patients(37 hips)that underwent conversion THA for failed HRA between October 2006 and May 2019 by a single surgeon was performed.Patient reported outcomes[modified Harris Hip Score(mHHS),University of California Los Angeles(UCLA)activity score]were obtained via an email-based responder-anonymous survey.Outcomes were compared to normative data of a primary THA cohort with similar demographics.Subgroup analysis was performed comparing outcomes of conversion THA for adverse local tissue reaction(ALTR)vs all other causes for failure.RESULTS The study group had a lower mHHS than the control group(81.7±13.8 vs 90.2±11.6,P<0.01);however,both groups had similar UCLA activity levels(7.5±2.3 vs 7.2±1.6,P=0.51).Patients that underwent conversion for non-ATLR causes had similar mHHS(85.2±11.5 vs 90.2±11.6,P=0.11)and higher UCLA activity levels(8.5±1.8 vs 7.2±1.6,P<0.01)compared to the control group.Patients that underwent conversion for ATLR had worse mHHS(77.1±14.5 vs 90.2±11.6,P<0.01)and UCLA activity levels(6.1±2.3 vs 7.2±1.6,P=0.05)when compared to the control group.CONCLUSION Patient outcomes equivalent to primary THA can be achieved following HRA conversion to THA.However,inferior outcomes were demonstrated for ALTR-related HRA failure.Patient selection and perhaps further studies examining alternative HRA bearing surfaces should be considered.

Effectiveness of the Suprainguinal Ultrasound-Guided Block for the Management of Postoperative Pain after Application of a Total Hip Prosthesis

Objective: To assess the effectiveness of ultrasound-guided supraginguinal block (SIB) in the management of pain after total hip replacement. Material and Methods: This was a prospective, randomized, single-blind controlled study carried out in the anesthesia-intensive care unit of the Donka National Hospital in Conakry, over a period of 06 months (01/01/2020 to 30/06/2020). It concerned 32 patients: 16 patients in the “ultrasound-guided SIB” group and 16 patients in the “standard analgesia” group. Results: The pain scores assessed by the simple verbal scale and collected at the different time intervals (6H, 12H, 24H, 36H, 48H) showed mean scores < 1 in the ultrasound-guided SIB group while the mean scores were ≤3 in the standard analgesia group (P < 0.001). On movement, the mean pain scores were ≤1 for the ultrasound-guided SIB group versus mean scores > 3 in the standard analgesia group (P < 0.001). The time to mobilization was greater than 48 hours in all patients in the standard analgesia group while it was less than 48 hours in the majority of patients (75%) in the ultrasound-guided SIB group. Nausea and vomiting were the most observed side effects. We did not observe any respiratory distress. The length of day hospitalization of patients in the ultrasound-guided SIB group was on average 5.50 ± 0.52 compared with 13.44 ± 1.55 in the group of standard analgesia patients (P = 0.001). The vast majority of patients in the ultrasound-guided SIB group were satisfied and unhappy in the standard analgesia group. Conclusion: Our study demonstrated that echo-guided SIB provided better analgesia compared to standard analgesia for the management of postoperative pain after total hip replacement.

Technical note for intraoperative determination of proper acetabular cup size in primary total hip arthroplasty

BACKGROUND Selecting the optimal size of components is crucial when performing a primary total hip arthroplasty.Implanting the accurate size of the acetabular component can occasionally be exacting,chiefly for surgeons with little experience,whilst the complications of imprecise acetabular sizing or over-reaming can be potentially devastating.AIM To assist clinicians intraoperatively with a simple and repeatable tip in elucidating the ambivalence when determining the proper acetabular component size is not straightforwardly achieved,specifically when surgeons are inexperienced or preoperative templating is unavailable.METHODS This method was employed in 263 operations in our department from June 2021 to December 2022.All operations were performed by the same team of joint reconstruction surgeons,employing a typical posterior hip approach technique.The types of acetabular shells implanted were:The Dynasty®acetabular cup system(MicroPort Orthopedics,Shanghai,China)and the R3®acetabular system(Smith&Nephew,Watford,United Kingdom),which both feature cementless press-fit design.RESULTS The mean value of all cases was calculated and collated with each other.We distinguished as oversized an implanted acetabular shell when its size was>2 mm larger than the size of the acetabular size indicator reamer(ASIR)or when the implanted shell was larger than 4 mm compared to the preoperative planned cup.The median size of the implanted acetabular shell was 52(48–54)mm,while the median size of the preoperatively planned cup was 50(48–56)mm,and the median size of the ASIR was 52(50–54)mm.The correlation coefficient between ASIR size and implanted acetabular component size exhibited a high positive correlation with r=0.719(P<0.001).Contrariwise,intraoperative ASIR measurements precisely predicted the implanted cups’size or differed by only one size(2 mm)in 245 cases.CONCLUSION In our study,we demonstrated that the size of the first acetabular reamer not entering freely in the acetabular rim corroborates the final acetabular component size to implant.This was also corresponding in the majority of the cases with conventional preoperative templating.It can be featured as a valid tool for avoiding the potentially pernicious complications of acetabular cup over-reaming and over-sizing in primary total hip arthroplasty.It is a simple and reproducible technical note useful for confirming the predicted acetabular cup size preoperatively;thus,its application could be considered routinely,even in cases where preoperative templating is unavailable.

Clinical Study on the Relationship between Fixation of Prosthesis and Health of Surrounding Tissues

[Objectives] To explore the effect of mouth outside bonding screw fixation and inside bonding fixation in implanting the prosthesis( crown or bridge) on the health of surrounding tissues,to provide a certain reference for the selection of fixation methods for clinically implanting the prosthesis. [Methods]160 cases of patients needing implanting the prosthesis due to dental arch deficiency were selected. They had excellent alveolar bone. They did not smoke,had no diabetes,and their bone tissue healing was at the early stage. They were randomly divided into A and B groups,80 cases in each group. Group A: the mouth inside and abutment of prosthesis was bonded to a single abutment crown or a single abutment bridge; the bonder on the surface of prosthesis was completely removed and then moved into the implant,and fixed with central retaining screw,this group was called " mouth outside bonding group". Group B: the abutment was located in the implant and fixed using central retaining screw,then the prosthesis( crown or bridge) was bonded to the abutment,the bonder on the surface of prosthesis was removed,and this group was called mouth " mouth inside bonding group". The health condition was compared between two fixing methods for the surrounding tissues of the implant in 24-36 months after restoration. [Results] Group A: the surrounding tissues of the implants for 126 teeth of 80 patients were healthy without occurrence of peripheral inflammation; Group B: in the implants of 112 teeth of 80 patients,7 teeth suffered the peripheral inflammation. Dental implant examination found that there was residue of bonder in the bonding of prosthesis and abutment,3 teeth exfoliated,and 4 teeth were restored after treatment. Through the X2 test,there was significant difference between Group A and Group B( P < 0. 05). [Conclusions] Implant-supported denture often adopts the mouth inside bonding. Since the bonder can not be removed completely,its residue will remain in gingival trough and stimulate the surrounding tissues of the implant and bring about the inflammatory reaction,and even lead to exfoliation of the implant; the mouth inside and abutment of prosthesis was bonded to a single abutment crown or a single abutment bridge,the bonder on the surface of prosthesis was completely removed and then moved into the implant,and fixed with central retaining screw. This method is an effective method for preventing the peripheral inflammation and increasing the success rate of dental implant.

Indication and surgical approach for reconstruction with endoprosthesis in bone-associated soft tissue sarcomas:Appropriate case management is vital

It is important for surgeons performing sarcoma surgery to know that bone resection and tumor prosthesis applications in soft tissue sarcomas(STS)have unique features in terms of indication,surgical approach and follow-up,in terms of the management of these cases.Some STS are associated with bone and major neurovascular structures.Bone-associated STS are generally relatively large and relatively deep-seated.Additionally,the tendency for metastasis is high.In some cases,the decision about which structures to resect is difficult.These cases are often accompanied by poor oncological and surgical outcomes.Management of cases should be done by a multidisciplinary team in advanced centers specialized in this field.The surgical team must have sufficient knowledge and experience in the field of limb-sparing surgery.Preoperative evaluation and especially good planning of bone and soft tissue reconstruction are vital.

Preparation for femur prosthesis of ceramic-metal combination artificial hip joint

Al 2O 3 material was synthesized by using high purity alumina micro powder and Mg Zr Y composite additives at temperature of 1 600 ℃, which had good mechanics property of 416 MPa bending strength and 5.46 MPa·m 1/2 fracture toughness. Femur head prosthesis of hip joint was prepared by using this material; Ti alloy femur handle was sprayed bioactive hydroxyapatite (HA) by plasma on surface, which improves the chemistry stability and biocompatibility of Ti alloy; ceramic metal combination artificial hip joint femur prosthesis was made by combining Al 2O 3 femur head with Ti alloy femur handle, so the manufacturing process is improved and the property and application flexibility are advanced.

An investigation on the dosimetric impact of hip prosthesis in radiotherapy

The objectives of this study are to evaluate the dosimetric impact of hip prosthesis using ELEKTA linac X-rays and compare the dose perturbations of metallic and nonmetallic hip prostheses. The local dose distributions of typical hip prostheses were calculated for 4, 8, and 15 MV beams by Geant4. Three prosthesis materials were selected in calculation to reveal the relation between material type and local dose perturbations of prostheses. Furthermore,the effect of nominal energy on prosthesis perturbation was also discussed and analyzed. Taking the calculated dose to the hip joint as reference, considerable differences were observed between prostheses and hip joints. In the prosthesis shadow region, the relative dose decreasing was up to 36, 21, and 16 % for the Co–Cr–Mo alloy, titanium alloy, and ceramic prostheses, respectively. In backscattering region, the relative dose increasing was about1–7 %. Overall, the results show that the dose perturbation effect of prostheses was mainly determined by material type, nominal energy, and density. Among these typical hip prostheses, ceramic prosthesis introduces the lowest dose perturbations.

Stress Analysis and Shape Design of a Femoral Hip Prosthesis

Objective:To study the stress distribution of the femoral hip prosthesis after the hip joint replacement.Methods:After the hip joint replacement,when the femur and prosthesis are considered as concentric cylinders with perfectly banded interface,a relatively perfect theoretical model of simulating the interfacial stress transfer is established.Results:The maximum interfacial shear stress occured at Z=0.At the cross-section of the femoral neck,interfacial shear stress decreased exponentially with the increases of the Z.Shear stress became very small at Z>0.1 m,which meant that the shear stress at the far end of the femoral hip prosthesis was very small.In order to avoid the stress concentration and femoral hip prosthesis sinking,interfacial stress must remain constant and balanced with the pressure load at Z=0.The radius of the femoral hip prosthesis changed with interfacial shear stress.The maximum value of the radius occured at Z=0,then it decreased at m.Specially,a=18.2 mm at Z=10 mm,a=5.36 mm at Z=98 mm,these are ideal radius.Conclusion:A theoretical model of simulating the interfacial stress is established when the femur and prosthesis are considered as concentric cylinders.The distributions of the interfacial shear and radial stresses with the axial positions are obtained.A theoretical reference for the design of the prosthesis is provided.

螺杆组合对阻燃HIPS产品性能及能耗影响的研究

采用不同长径比的双螺杆挤出机制备HIPS阻燃料,对阻燃HIPS的阻燃性能进行了比较,通过测量挤出机的功率来计算其能耗并测试了试样的抗拉强度。结果表明,在一定的长径比范围内,大长径比耗能相对最低,能够节省大量能源,有利于工业化生产。