Proven and nonproven facts in knee arthroplasty. Results with the semiconstrained GSB-prosthesis

The great number of knee-replacement systems makes a comparative study difficult. Even more confusing are the different criteria used for the evaluation of the results. After a critical review of what can be taken as proven facts, our own experience with the semiconstrained GSB-III knee prosthesis is critically analyzed. The survivorship method is used, presenting the cumulative success rate and analyzing the reasons for the failure rates. We feel that all authors presenting results of knee arthroplasty should adopt this method, using the same or at least comparable evaluation sheets (for instance, that of ERASS). Moreover, more attention should be given to bone dynamics in a prospective study using modern technology (CT densitometry). This will help to detect possible factors responsible for the failure of knee arthroplasty and possibly to prevent failure with medication.     

Revision after total knee arthroplasty and unicompartmental knee arthroplasty in the medicare population

This study compares the relative risk of revision and associated risk factors after total or unicompartmental knee arthroplasty (TKA or UKA) in the Medicare population. A total of 61 767 TKA and 2848 UKA patients were identified. Reviewed data included type of treatment, gender, age, race, Charlson Index for comorbidity, length of stay, Medicare buy-in for socioeconomic status, region, and year. Unicompartmental knee arthroplasty patients were at increased risk for revision at 2 and 5 years. Those patients undergoing UKA were significantly more likely to require revision in the first 5 years as compared with those undergoing TKA. Risk factors contributing to TKA revision included younger male patients with higher comorbidities and lower socioeconomic status. About UKA, lower revision rates tend to favor those surgeons with higher volume.     

Hydroxyapatite in knee arthroplasty

Summary HA interface remains controversial in knee replacement especially as regards the tibial component. When speaking about non cemented knees the poor results afforded by the porous coatings especially microbeads or fibermesh made many surgeons fall in doubt about non using acrylic cement. HA coatings provide us with a very new biologic system and has to be considered as definitely different :1- Biological evidence of reliable implant bonding: Histological analysis performed by many authors including Thomas Bauer from Cleveland demonstrated that there is a very intimate contact between bony formations and metallic substract thanks to HA. This provides very good interlock and long lasting fixation. If the coating resorbs after several years, this resorbtion is a part of the regular bony turn over and HA is replaced by bone. This is finally the ultimate goal of replacement when reliable and sound fixation is achieved directly by the host bone.2- Hip HA experience is very successful at 10 year of FU: We started our hip experience 12 years ago in May '87. To date our personal experience with HA hips reaches 2 000 cases. Results were reported at the Barcelona '97 meeting held by the European Federation of National Associations of Orthopaedic and Traumatology (EFORT). This paper summed up the results of a non selected series. Then global survival rate was 0.985 at 10 year and these results look encouraging and at least as good as the best cemented series.3- HA total knee arthroplasty. A 9-year experience: Our personal experience in TKR using the Omnifit knee started 9 years ago in 1990. The first implant was the 3000 distal-coated Omnifit knee and we now currently use the 7000 fully coated knee. Based upon a series of 51 cases over 5 year of FU (5 to 7 year) of which 100% were reviewed for this study, the knee score according to the International Knee Society score was 96.2 out of 100 (ranging 77 up to 100). The mean function score was 93.2 (ranging from 85 up to 100). To date the failure rate is 0% and we had no clinical failure and no evidence of loosening. Finally the most important finding as regards the HA biological interface was demonstrated by the ability for bone to fill in previous lucent line due to fibrous tissue layer.Finally HA seems to be considered as a reliable third track as our 7 year experience is very encouraging. Radiological stability of patterns over 5 to 9 year, the seal afforded by HA preventing from migrating osteolysis, and mainly the ability for HA to fill in gaps over the years and transform fibrous tissue into bone may be considered as critical assets.     

Total knee arthroplasty in the valgus knee

Valgus knee deformity is a challenge in total knee arthroplasty (TKA) and it is observed in nearly 10 % of patients undergoing TKA. The valgus deformity is sustained by anatomical variations divided into bone remodelling and soft tissue contraction/elongation. Bone tissue variations consist of lateral cartilage erosion, lateral condylar hypoplasia and metaphyseal femur and tibial plateau remodelling. Soft tissue variations are represented by tightening of lateral structures: lateral collateral ligament, posterolateral capsule, popliteus tendon, hamstring tendons, the lateral head of the gastrocnemius and iliotibial band. Complete pre-operative planning and clinical examination are mandatory to manage bone deformities and soft tissue contractions/elongations and to decide if a higher constrained prosthesis is necessary. Two different approaches have been described to perform TKA in a valgus knee: the anteromedial approach and the anterolateral one. In valgus knee deformity bone cuts can be performed differently in order to correct low-grade deformities and reduce great deformities. There is still debate in the literature on the sequence of lateral soft tissue release to achieve the best alignment without any instability. The aim of this article is to review the anatomical variations underlying a valgus knee, to assess the best pre-operative planning and to evaluate how to choose the grade of constraint of the implant. We will also review the main approaches and surgical techniques both for bone cuts and soft tissue management. Finally, we will report on our experience and technique.     

人工膝关节单髁关节置换术研究进展

单髁关节置换术治疗单间室骨关节炎近些年取得很大进展,引起越来越多的关注.文中综述了近年来最新的研究进展.研究表明经严格的病例选择,单髁关节置换术10年生存率达95%左右.术后关节功能好,并发症少,具有损伤小、恢复快、费用低、保存骨量等优点,是治疗单间室关节炎值得考虑的手术选择.     

Total knee arthroplasty

Eighty-six nonhinged total knee arthroplasties performed between 1971 and 1981 have been reviewed. Fifty-one were of the geometric type and 35 of the anametric type. The use of both units resulted in a statistically and clinically significant improvement in preoperative pain and an increase in functional activities. Three of 51 geometric units developed loose components that required revision. None of the 35 anametric units has required revision for loosening. Partial radiolucent lines at the tibial bone-cement interface were noted in 43% of the group. Data analysis of age, weight, and sex demonstrated no statistically significant characteristic of this group when compared with the group without radiolucent lines. However, radiolucent lines were more common in those patients with osteoarthritis than in the group with rheumatoid arthritis. In addition, radiolucent lines were noted in 90% of knees in which a metal-backed tibial tray with a central post was used, compared with 36% of knees without metal-backed tibial components. Relief of pain and correction of instability and deformity can be achieved for most patients following nonhinged total knee arthroplasty.     

Spherocentric knee arthroplasty

The spherocentric knee, designed to allow triaxial rotation and provide intrinsic stability, includes desirable design features of metal on high density polyethelene bearing surfaces, metal support for all plastic components, metal-cement-bone interfacing for all fixation surfaces, sufficient strength to eliminate fatigue fracture of metallic components as a potential source of failure, cam deceleration for hyperextension control, and an inverted central plastic socket which minimizes wear. The system assures a low coefficient of friction and thereby minimizes loosening. This prosthesis has been used for surgical arthroplasty in 134 knees with gross instability or severe fixed deformity or both, in which optimal results would not have been anticipated with non-articulated resurfacing prostheses. The patients have been followed for an average of nearly 3 years (range one to 5 years). Results in terms of correction of deformity, improvement of stability, range of motion, pain relief and improved function, have been outstanding. Problems of infection, loosening and fracture of adjacent bone have been less than with other intrinsically stable prostheses (hinge prostheses) and are less than most reports of non-articulated resurfacing prostheses followed for a comparable time. There have been no failures within the prosthesis. Our loose prostheses represent failures that occurred between the prostheses and the bone. The spherocentric prosthesis is the prosthesis of choice for arthroplasty of a knee with severe preoperative deformity or severe instability or both in which optimal results would not be anticipated following insertion of a resurfacing type of prosthesis.     

Unicompartmental knee arthroplasty

Recent increased interest in less invasive surgical techniques has led to a concurrent resurgence in unicompartmental knee arthroplasty. The procedure has evolved significantly over the past three decades. Proponents of unicompartmental knee arthroplasty cite as advantages lower perioperative morbidity and earlier recovery. Both clinical outcome and kinematic studies have indicated that successful unicompartmental knee arthroplasty functions closer to a normal knee. Recent reports have demonstrated success in expanding the classic indications of unicompartmental knee arthroplasty to younger and heavier patients. Both fixed- and mobile-bearing implants can yield excellent clinical outcomes at >10 years, but with different modes of long-term failure. Proper execution of surgical technique remains critical to optimizing outcome. Long-term studies are needed to appropriately define the role of less invasive unicompartmental surgical approaches as well as the role of computer navigation.     

Unicompartmental knee arthroplasty

Unicondylar knee arthroplasty is an alternative to tibial osteotomy for the treatment of medial or lateral compartment noninflammatory arthritis. It must be considered in the context of the other viable surgical options for treatment of this disorder. Appropriate patient selection and careful surgical technique will provide good to excellent results in over approximately 90% of individuals while preserving bone stock and ligamentous structures for revision if necessary.     

全膝关节置换治疗膝关节骨关节炎

目的研究全膝关节置换治疗骨关节炎的近中期手术效果,探讨手术方法与术后效果。 方法回顾性分析了皖南医学院弋矶山医院2010年7年至2018年3月临床资料。膝关节骨关节炎手术患者共81例,平均疼痛时间(8±3)年,均采用后稳定型假体,膝关节内外翻、屈曲畸形通过术中骨赘清理、内外侧副韧带和后方关节囊等软组织松解等技术矫正。术后关节囊内注入氨甲环酸抗凝及早期进行康复治疗。术前及术后拍摄下肢全长X片及膝关节正侧位X片记录股胫角度和屈曲畸形角度,统计手术时间、术后引流量。术后随访1、3、6、12、24月复查膝关节正侧位X线,记录膝关节活动度和疼痛情况,并进行膝关节协会评分(KSS)。用SPSS 17.0软件,数据采用配对t检验分析。 结果平均随访时间(22±5)个月,手术时间平均(71±6)min,引流量平均(380±5)ml,膝关节股胫角术后平均为(1.3±1.0)°,术后有4例术后出现膝前痛。无血管及神经损伤等并发症,下肢力线基本恢复正常。无术后感染发生。随访复查膝关节正侧位X线片,未发现假体松动、下沉。随访膝关节活动度、疼痛。膝关节KSS评分有显著改善(临床t＝－66,功能t＝－91.7,P<0.05) 。 结论全膝关节置换术治疗膝关节骨关节炎,术中应用骨赘清理、内外侧,后方关节囊等软组织松解等手术技术,可纠正内外翻畸形,恢复下肢力线、改善膝关节活动度和缓解疼痛,临床效果满意。     

Medial unicompartmental knee arthroplasty in the ACL-deficient knee

Symptomatic osteoarthritis (OA) of the knee develops often in association with anterior cruciate ligament (ACL) deficiency. Two distinct pathologies should be recognised while considering treatment options in patients with end-stage medial compartment OA and ACL deficiency. Patients with primary ACL deficiency (usually traumatic ACL rupture) can develop secondary OA (typically presenting with symptoms of instability and pain) and these patients are typically young and active. Patients with primary end stage medial compartment OA can develop secondary ACL deficiency (usually degenerate ACL rupture) and these patients tend to be older. Treatment options in either of these patient groups include arthroscopic debridement, reconstruction of the ACL, high tibial osteotomy (HTO) with or without ACL reconstruction, unicompartmental knee arthroplasty (UKA) and total knee arthroplasty (TKA). General opinion is that a functionally intact ACL is a fundamental prerequisite to perform a UKA. This is because previous reports showed higher failure rates when ACL was deficient, probably secondary to wear and tibial loosening. Nevertheless in some cases of ACL deficiency with end-stage medial compartment OA, UKA has been performed in isolation and recent papers confirm good short- to mid-term outcome without increased risk of implant failure. Shorter hospital stay, fewer blood transfusions, faster recovery and significantly lower risk of developing major complications like death, myocardial infarction, stroke, deep vein thrombosis (as compared to TKA) make the UKA an attractive option, especially in the older patients. On the other hand, younger patients with higher functional demands are likely to benefit from a simultaneous or staged ACL reconstruction in addition to UKA to regain knee stability. These procedures tend to be technically demanding. The main aim of this review was to provide a synopsis of the existing literature and outline an evidence-based treatment algorithm.     

Total knee arthroplasty in the valgus knee.

The valgus knee presents a unique set of problems that must be addressed during total knee arthroplasty. Both bone and soft-tissue deformities complicate restoration of proper alignment, positioning of components, and attainment of joint stability. The variables that may need to be addressed include lateral femoral condyle or tibial plateau deficiencies secondary to developmental abnormalities, and/or wear; primary or acquired contracture of the lateral capsular and ligamentous structures; and, occasionally, laxity of the medial collateral ligament. Understanding the specific pathologic anatomy associated with the valgus knee is a prerequisite to selecting the proper surgical method to optimize component position and restore soft-tissue balance.     

Total knee arthroplasty in nonagenarians

Between 1976 and 1999, 3714 consecutive primary total knee arthroplasties (TKAs) were done at our institution. Of these, 20 (0.54%) TKAs were done in 18 patients who were > or =90 years old. The average follow-up period was 62.2 months. There was 1 postoperative death among the nonagenarians within 90 days of surgery. All patients had complete pain relief and excellent knee scores using the Knee Society clinical assessment scale. None had an excellent function score at final follow-up examination, however. Only 1 patient experienced any surgical complications; the patient had wound dehiscence. Five (26.3%) of the surviving 19 patients had medical complications. The average length of hospital stay was 10.1 days. Although TKA produced only moderate improvement in knee function for the nonagenarians, it produced excellent clinical improvement. TKA improved the patients' ability to manage the activities of daily living and their quality of life.     

Revision of the Gunston polycentric knee arthroplasty with total knee arthroplasty

The Gunston polycentric knee arthroplasty, first designed and performed by Frank Gunston in 1971, is the first prosthesis considering the natural knee biomechanics. Although the polycentric knee arthroplasty showed encouraging results to relieve pain and to preserve the preoperative range of motion and joint instability, the improvements in prosthesis design and arthroplasty technology rapidly made the polycentric knee prosthesis obsolete. Herein, we report a 58-year old male patient who had revision of the Gunston polycentric knee arthroplasty with total knee arthroplasty performed 32 years after the initial operation.     

Preoperative knee stiffness and total knee arthroplasty outcomes

A retrospective case-control study was conducted to evaluate 1-year total knee arthroplasty (TKA) outcomes among preoperative stiff knees, range of motion (ROM) 80° or less, compared with nonstiff preoperative knees, ROM 100° or greater. A total of 134 stiff knee cases were compared with a matched cohort of 134 non-stiff knee controls. Knee Society Score and Oxford Knee Score change scores from baseline to 1 year were similar between the groups. Stiff knees experienced a significantly greater mean improvement in ROM from baseline to 1 year (30.8° ± 18.8°) as compared with nonstiff knees (1.1° ± 12.8°) (P < .0001). Although ultimate ROM of a TKA can be restricted secondary to preoperative stiffness, improvements in outcomes and ROM are not affected. We conclude that progression of stiffness should not in and of itself lead to earlier intervention of TKA in most cases.     

Unicompartmental and total knee arthroplasty

Pain is the main indication for a total knee arthroplasty, and the choice of prosthesis should depend on the arthritic involvement of the joint. There is no substitute for early motion after the operation to regain knee motion. Unicompartmental replacement is valuable to preserve ligament and bony stock in properly selected cases. Excellent results can be expected in even elderly patients with severe arthritis if the operation is well performed.     

Stiffness in total knee arthroplasty

Stiffness is a relatively uncommon complication after total knee arthroplasty. It has been defined as a painful limitation in the range of movement (ROM). Its pathogenesis is still unclear even if some risk factors have been identified. Patient-related conditions may be difficult to treat. Preoperative ROM is the most important risk factor, but an association with diabetes, reflex sympathetic dystrophy, and general pathologies such as juvenile rheumatoid arthritis and ankylosing spondylitis has been demonstrated. Moreover, previous surgery may be an additional cause of an ROM limitation. Postoperative factors include infections, arthrofibrosis, heterotrophic ossifications, and incorrect rehabilitation protocol. Infections represent a challenging problem for the orthopaedic surgeon, and treatment may require long periods of antibiotics administration. However, it is widely accepted that an aggressive rehabilitation protocol is mandatory for a proper ROM recovery and to avoid the onset of arthrofibrosis and heterotrophic ossifications. Finally, surgery-related factors represent the most common cause of stiffness; they include errors in soft-tissue balancing, component malpositioning, and incorrect component sizing. Although closed manipulation, arthroscopic and open arthrolysis have been proposed, they may lead to unpredictable results and incomplete ROM recovery. Revision surgery must be proposed in the case of well-documented surgical errors. These operations are technically demanding and may be associated with high risk of complications; therefore they should be accurately planned and properly performed.     

Total knee arthroplasty in hemophilia

Twenty-four total knee arthroplasties were performed in fourteen disabled patients with hemophilia. The average age of the patients at operation was thirty-five years. Twenty-one of the implants that were used were total condylar prostheses. Using The Hospital for Special Surgery knee-rating system after two to nine years of follow-up, the result in fifteen knees was rated as excellent; in six, as good; and in one, as fair. Two patients had a poor result that was attributable to late infection. Pain and function were markedly improved, and the average gain in range of motion was 23 degrees. Postoperative complications, in addition to the infections, included one subcutaneous hematoma, one hemolytic anemia, and one instance of inhibition to Factor VIII. The technical problems in treatment were formidable. Total knee arthroplasty in a hemophiliac can be successful, but it should be performed only with strict hematological supervision. The surgeon should be prepared to treat many potential postoperative complications.