Immediate Effects of Meniscectomy on the Knee Joint: The Effects of Tensile Load on Knee Joint Ligaments in Dogs

Tensile strength variables for the collateral ligaments were compared after excision of the meniscus in one knee, the corresponding meniscus in the contralateral knee of the same dog being intact. Removal of the meniscus was associated with a three-fold increase in initial laxity, two-fold for the lateral and three-fold for the medial ligament. The maximum tensile load uptake of the medial collateral ligament was reduced by more than 10 per cent after medial meniscectomy; the load uptake of the lateral ligament was not affected by lateral meniscectomy. It is proposed that tensile loads are distributed more favourably in the medial collateral ligament by the intact medial meniscus with firm capsular attachments than in the “normal“ ligament after meniscectomy.     

Design-related risk factors for revision of primary cemented stems: Analysis of 3 common stems in the Swedish Hip Arthroplasty Register

Background and purpose

Even small design variables of the femoral stem may influence the outcome of a hip arthroplasty. We investigated whether design-related factors play any role in the risk of non-aseptic revision of the 3 most frequently used primary cemented stem designs in the Swedish Hip Arthroplasty Register.

Patients and methods

We studied 71,184 primary cemented femoral stem implants (21,008 Exeter polished stems, 43,036 Lubinus SPII stems, and 7,140 Spectron EF Primary stems) that were inserted from 1999 through 2006. Design-specific characteristics were analyzed using separate Cox regression models that were adjusted for sex, age, diagnosis, incision, and number of operations (first vs. second).

Results

The crude revision rate varied between 0.8% (Lubinus SPII) and 1.4% (Spectron Primary). For the Exeter stem, the smallest femoral head diameter (22 mm) was associated with a higher risk of revision. No other design-specific parameters influenced the risk of revision of the Exeter stem. The smallest Lubinus stem size, a stem with extended neck length combined with a femoral head with increasing neck length, or the use of a cobalt-chromium head had a negative influence on the outcome. For the Spectron stem, the risk of revision was elevated for the smallest stem and for increasing offset calculated as the combined effect of high offset design and increasing neck length.

Interpretation

Overall revision rates were low, but for two of the stems studied design factors such as size and neck length or offset influenced the risk of non-aseptic revision.     

Long Term Results of Surgery for Non-Acute Anteromedial Rotatory Instability of the Knee

Seventy-eight patients treated by extraarticular reconstruction including pes anserinus transfer for anteromedial rotatory instability of the knee were reinvestigated 16-47 months (mean 28) after operation. Function before and after operation was assessed by means of a knee rating score. Of these patients, 94 per cent showed a higher score after operation. Twenty per cent showed full recovery with no limitation of knee function whatsoever. The follow-up score was higher with preserved medial meniscus function than when this structure had been removed. When not initially torn, the medial meniscus tended to become involved with time. Mild laxity in extension, possibly indicative of a posterior cruciate injury previously underestimated or not observed, was found in 15 per cent of the patients. No correlation was found between late knee function and the interval between injury and operation or the interval between operation and follow-up examination.

The long term results were good. Extraarticular reconstruction is thus indicated in cases of chronic rotatory instability of the anteromedial type. Routine meniscectomy is not recommended in these patients, however. Signs possibly indicating posterior cruciate ligament involvement should be carefully looked for, as even minor posterior cruciate injury, easily overlooked, may influence the late results.     

关节镜下微骨折术治疗膝关节软骨损伤

[目的]分析关节镜下膝关节软骨损伤的特点并探讨采用微骨折术治疗的手术方法和疗效。[方法]对2003年2月~2005年8月79例膝关节软骨损伤患者采取关节镜下微骨折术治疗,男38例,女41例;左膝35例,右膝34例;平均年龄38.3岁(15~57岁)。术前膝关节症状持续时间平均11个月(3~23个月),其中有明确外伤史48例,占60.7%。软骨成形术基础上采用微骨折尖椎在软骨缺损区钻孔,孔径3 mm,孔间距3 mm,孔深3 mm。[结果]79例患者共发现软骨损伤131处,平均每例存在软骨损伤1.6处,其中股骨内髁和髌骨关节面最常见,分别占33.6%和22.1%;软骨损伤程度按Outerbridge分级最常见为Ⅳ级损伤,占60.3%;软骨损伤面积多数在1~2 cm2,占43.5%。术后随访73例,失访6例,随访率92.4%,平均随访17个月(10~33个月),采用Tegner运动评级和Lysholm膝关节评分进行评价,45例优,18例良,16例差,优良率79.7%;Lysholm膝关节评分由术前平均43分提高到术后88分。[结论]关节镜下微骨折术方法简单,操作方便,是治疗膝关节全层软骨损伤的一种安全有效方法,不管是急性或慢性软骨损伤,均可明显改善患者的关节功能和减轻疼痛症状,提高生活质量。     

Surgical technique for articular cartilage transplantation to full-thickness cartilage defects in the knee joint

Focal arthritic defects in the knee lead to pain, swelling, and dysfunction. Treatment of the defects has includeddrilling, abrasion, and grafting. This report describes our surgical technique of autogenous articular cartilage grafting of arthritic and traumatic articular cartilage lesions. Articular cartilage grafting can be performed as a single arthroscopic outpatient procedure. The mixture of articular cartilage and cancellous bone appears to provide a supportive matrix for cartilage formation. Pain relief is excellent if careful surgical technique and a defined rehabilitation program is followed. Further collagen typing data and additional biopsies will reveal more about the durability of the newly formed cartilage.     

特异性COX-2抑制剂保护骨关节炎软骨的临床观察

目的探讨特异性COX-2抑制剂对骨关节炎的关节软骨保护作用的临床研究。方法门诊选取膝关节骨关节炎患者80例,随机分为特异性COX-2抑制剂组和维骨力对照组,各40例,单盲给药。应用平均Womac关节炎指数评分和平均OA严重程度指数评定两组用药前后临床症状改善情况及使用血清软骨代谢标志物蛋白聚糖与型胶原和关节MRI进行检测关节软骨结构与功能的改变情况,并作统计学分析。结果经12个月治疗观察,特异性COX-2抑制剂组的平均Womac关节炎指数评分和平均OA严重程度指数在前3个月改善明显优于维骨力对照组(P<0.01),但在治疗12个月后,两组差异不显著(P>0.05);治疗12个月后特异性COX-2抑制剂组的软骨代谢指标蛋白聚糖和型胶原及关节MRI均显示组内变化显著(P<0.01),而与维骨力组对比结果无显著性差异(P>0.05)。结论特异性COX-2抑制剂对骨关节炎的软骨有保护和促进修复作用,兼有抗炎与保护软骨双重疗效,它是一类既能改善关节炎症状又能改善关节软骨结构的药物,值得临床广泛应用。同时本研究为其在临床应用和进一步研究此类药物提供了更好的理论基础和依据。     

Altered tibiofemoral position following ACL reconstruction is associated with cartilage matrix changes: A voxel-based relaxometry analysis

The purpose of this study was to analyze the relationship between postsurgical tibial translation (TT) and tibial rotation (TR) with cartilage matrix changes using quantitative magnetic resonance imaging, specifically voxel-based relaxometry with T1ρ and T2 mapping sequences. Knee magnetic resonance imaging's (MRI's) of 51 patients with unilateral anterior cruciate ligament injury, no concomitant ligamentous injury, history of osteoarthritis (OA), and previous knee surgery were scanned prior to surgery. Thirty-four patients completed follow-up MRI scans at 6-month, 1- and 2-year post-reconstruction and were included in this study. Knee biomechanics, T1ρ, and T2 were calculated using an in-house Matlab program. Compared to the contralateral knee, the injured knee demonstrated significantly increased anterior TT at baseline (P < .001), 6-month (P < .001), 1- (P = .001), and 2-year (P < .001). Furthermore, patients were divided into groups based on TT at 6-month. When compared to patients with normal TT, those with increased anterior TT at 6-month displayed significantly longer T1ρ and T2 relaxation times in 10.4% and 7.4% of the voxels in the injured medial tibia at 1-year, respectively, as well as 12.4% and 9.8% of the voxels in the injured medial tibia at 2-year, respectively. Our results demonstrate an association between abnormal tibiofemoral position and early degradative changes to the articular cartilage matrix of the injured knee. Clinical significance: These findings suggest that altered tibiofemoral position following ACL reconstruction is associated with early degeneration of knee cartilage. Future prospective studies employing longer follow-up times are warranted to evaluate the relationship between abnormal tibiofemoral position and the early onset of posttraumatic OA.     

Anterior Displacement of the Tibial Tuberosity in the Treatment of Chondromalacia Patellae

Anterior displacement of the tibial tuberosity combined with shaving of the diseased cartilage was used as treatment for chondromalacia patellae in 32 knees in 28 consecutive patients and in one patient with chondromalacia femoris. the patients were aged 17 to 57 years. One patient had earlier sustained a serious injury to the ligaments of the knee, resulting in instability. All patients except one were unfit for work before the operation. Postoperative extra-articular wound infection was noted in two knees and venous thrombosis occurred in three legs. the postoperative observation period varied from 8 months to 2 years and 10 months. in one knee the anterior displacement of the tibial tuberosity was not maintained. in lateral radiographs the anterior displacement of the tibial tuberosity in the other knees varied from 10 to 23 mm. the relief from pain obtained by the operative treatment was estimated as good in all knees except three, which were unchanged. All patients became fit for work and/or sport.     

Anterior Displacement of the Tibial Tuberosity in the Treatment of Chondromalacia Patellae

Anterior displacement of the tibial tuberosity combined with shaving of the diseased cartilage was used as treatment for chondromalacia patellae in 32 knees in 28 consecutive patients and in one patient with chondromalacia femoris. the patients were aged 17 to 57 years. One patient had earlier sustained a serious injury to the ligaments of the knee, resulting in instability. All patients except one were unfit for work before the operation. Postoperative extra-articular wound infection was noted in two knees and venous thrombosis occurred in three legs. the postoperative observation period varied from 8 months to 2 years and 10 months. in one knee the anterior displacement of the tibial tuberosity was not maintained. in lateral radiographs the anterior displacement of the tibial tuberosity in the other knees varied from 10 to 23 mm. the relief from pain obtained by the operative treatment was estimated as good in all knees except three, which were unchanged. All patients became fit for work and/or sport.     

Increased risk of revision in patients with non-traumatic femoral head necrosis

Background and purpose Previous studies of patients who have undergone total hip arthroplasty (THA) due to femoral head necrosis (FHN) have shown an increased risk of revision compared to cases with primary osteoarthritis (POA), but recent studies have suggested that this procedure is not associated with poor outcome. We compared the risk of revision after operation with THA due to FHN or POA in

the Nordic Arthroplasty Register Association (NARA) database including Denmark, Finland, Norway, and Sweden.

Patients and methods 427,806 THAs performed between 1995 and 2011 were included. The relative risk of revision for any reason, for aseptic loosening, dislocation, deep infection, and periprosthetic fracture was studied before and after adjustment for covariates using Cox regression models.

Results 416,217 hips with POA (mean age 69 (SD 10), 59% females) and 11,589 with FHN (mean age 65 (SD 16), 58% females) were registered. The mean follow-up was 6.3 (SD 4.3) years. After 2 years of observation, 1.7% in the POA group and 3.0% in the FHN group had been revised. The corresponding proportions after 16 years of observation were 4.2% and 6.1%, respectively. The 16-year survival in the 2 groups was 86% (95% CI: 86–86) and 77% (CI: 74–80). After adjusting for covariates, the relative risk (RR) of revision for any reason was higher in patients with FHN for both periods studied (up to 2 years: RR = 1.44, 95% CI: 1.34–1.54; p < 0.001; and 2–16 years: RR = 1.25, 1.14–1.38; p < 0.001).

Interpretation Patients with FHN had an overall increased risk of revision. This increased risk persisted over the entire period of observation and covered more or less all of the 4 most common reasons for revision.     

New algorithm for simulation of proteoglycan loss and collagen degeneration in the knee joint: Data from the osteoarthritis initiative

Osteoarthritis is a harmful joint disease but prediction of disease progression is problematic. Currently, there is only one modeling framework which can be applied to predict the progression of knee osteoarthritis but it only considers degenerative changes in the collagen fibril network. Here, we have developed the framework further by considering all of the major tissue changes (proteoglycan content, fluid flow, and collagen fibril network) occurring in osteoarthritis. While excessive levels of tissue stresses controlled degeneration of the collagen fibril network, excessive levels of tissue strains controlled the decrease in proteoglycan content and the increase in permeability. We created four knee joint models with increasing degrees of complexity based on the depth‐wise composition. Models were tested for normal and abnormal, physiologically relevant, loading conditions in the knee. Finally, the predicted depth‐wise compositional changes from each model were compared against experimentally observed compositional changes in vitro. The model incorporating the typical depth‐wise composition of cartilage produced the best match with experimental observations. Consistent with earlier in vitro experiments, this model simulated the greatest proteoglycan depletion in the superficial and middle zones, while the collagen fibril degeneration was located mostly in the superficial zone. The presented algorithm can be used for predicting simultaneous collagen degeneration and proteoglycan loss during the development of knee osteoarthritis. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1673–1683, 2018.

     

Risk factors for radiographic joint space narrowing and patient reported outcomes of post‐traumatic osteoarthritis after ACL reconstruction: Data from the MOON cohort

The Multicenter Orthopaedic Outcomes Network (MOON) is an NIH‐funded prospective, longitudinal cohort of over 3,500 patients who have undergone anterior cruciate ligament reconstruction (ACLR) by 14 sports medicine surgeons at 7 academic medical centers. Patient reported outcome questionnaires (PRO's) are completed at baseline and multiple timepoints after surgery, and a nested cohort of patients return for radiographs to assess the development of joint space changes. We review the risk factors for worse patient reported outcomes, the predictors of clinically significant symptoms of post‐traumatic osteoarthritis (PTOA), and the factors associated with more radiographic joint space narrowing. Baseline PRO's were highly predictive of follow‐up scores. Factors associated with worse PRO's at 2 and 6 years included female sex, higher BMI, smoking, less education, allograft, medial meniscectomy, or repair, and chondral injury. Partial lateral meniscectomy was unexpectedly associated with better PRO's. Factors associated with clinically significant symptoms of PTOA at 2 and 6 years included subsequent surgery, meniscal pathology, and chondral injury. Factors associated with narrower medial compartment joint space width included medial meniscectomy, medial meniscus repair, and increased age. Medial joint space width was slightly wider overall for the ACLR knees compared to the contralateral normal knees. Future studies will evaluate PRO's and radiographs at 10‐year follow‐up. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1366–1374, 2017.

     

Why lateral meniscectomy is more dangerous than medial meniscectomy. A finite element study.

Total meniscectomies are commonly thought to cause progressive degenerative arthrosis pathology in articular cartilage in a period of a few years because of alteration of the biomechanical environment including increased joint instability. This concern has lead to a preference for partial meniscectomies, although lateral partial meniscectomies sometimes lead to catastrophic results. We performed a three-dimensional finite element model of the human tibiofemoral joint to examine the effect of lateral meniscectomy on knee biomechanics. The results were compared to those from modeling a medial meniscectomy. Under axial femoral compressive loads, the peak contact stress and maximum shear stress in the articular cartilage increased 200% more after a lateral than a medial meniscectomy. These increased stresses could partly explain the higher cartilage degeneration observed after a lateral meniscectomy.     

Morphology of the transepicondylar axis and its application in primary and revision total knee arthroplasty

A morphologic anatomic study was done of the lower extremity to investigate various relationships of the transepicondylar axis (TEA). Thirteen cadaver specimens were dissected and mounted to a metal frame with a pin passing through the TEA. The center of the knee was determined as the depth of the anterior intercondylar groove. The ratio of the upper leg to lower leg measured from femoral head center and ankle center to TEA was 1.02. The mean distance of the TEA to the joint line was 3.08 cm medial and 2.53 cm lateral. The mean femoral angle comparing the TEA to mechanical axis was 0.61° varus. The mean tibial angle comparing the TEA to the mechanical axis was 0.4° varus in extension and 0.43° in flexion, with no significant difference in the lower extremity angle with flexion (P < .01). The TEA is an important landmark that, from this study, is virtually perpendicular to the mechanical axis of the lower extremity and parallels the knee flexion axis. Femoral component rotation and joint line positioning in total knee arthroplasty can be determined using the TEA.     

不同手术方式对关节软骨影响的实验研究

[目的]了解3种不同手术方式对活体关节软骨的影响。[方法]用光镜、扫描电镜及生物化学方法观察3种手术后不同时点兔膝关节软骨的结构及基质蛋白多糖的变化。[结果]3种手术对关节软骨都会造成损伤，使蛋白多糖的含量降低，暴露组造成不可逆性损伤，保护组和灌注组造成可逆性损伤，灌注组软骨损伤最轻、恢复最快。[结论]3种关节手术均会造成关节软骨损伤，关节灌注组的影响最小。     

Meniscus transplantation using a cryopreserved allograft. Histological and ultrastructural study of the transplanted meniscus

We performed allogenic meniscus transplantation in rabbits and investigated the regenerative process in the transplanted meniscus with particular respect to its ultra-structure. Under a transmission electron microscope, the chondrocytes and extracellular matrix were degenerated or destroyed in week 0. Fibroblasts were observed 4–8 weeks postoperatively. Immature chondrocytes emerged at 12 postoperative weeks. At 16 weeks, the newly formed chondrocytes and extracellular matrix were virtually normal. Although the diameter of collagen fibrils still varied, their arrangement was dense and the filaments had almost normal banding. This study demonstrated that newly formed chondrocytes may differentiate from fibroblasts 8–12 weeks after transplantation. The fibroblasts synthesized collagen fiber and glycosaminoglycan, indicating that repair of the extracellular matrix may be initiated 4–8 weeks postoperatively, becoming were active after 12 weeks when the newly formed chondrocytes emerge. The extracellular matrix is injured during rapid freezing, cryopreservation, and slow thawing, and repair is delayed due to this deterioration. The extracellular matrix thus needs to be protected from injury as far as possible in order to promote its repair, since it normalizes more slowly than chondrocytes. Received for publication on Feb. 25, 1998; accepted on Oct. 1, 1998     

No need for routine closed suction drainage in elective arthroplasty of the hipA prospective randomized trial in 104 operations

The importance of the medial collateral ligament and the anterior cruciate ligament of the knee in relation to valgus and varus instability was investigated. Mobility patterns were drawn from ten osteoligamentous knee preparations after successive transections of the structures. Cutting the entire collateral medial ligament caused only slight valgus instability, even when the knee was flexed. Further transection of the anterior cruciate ligament increased the instability considerably, but the knee remained stable in extension. The valgus instability after the transections was maximal at about 60° of flexion.     

膝关节软骨缺损的修复方法与策略

关节软骨缺损十分常见,是导致关节退变的重要因素之一.由于缺乏血供,自身再生能力有限,因此,临床尝试多种方法来修复这些缺损.具体采用何种方法,应根据软骨缺损的病理类型来制定最优策略.