Anteroposterior radiographs of the osteoarthritic knee

Destruction of the articular cartilage is the first change seen on gross examination of the knee in osteoarthritis. Weight-bearing radiographs are conventionally taken with the knee in full extension. Biomechanical studies have shown, however, that the major contact stresses in the femorotibial articulation occur when the knee is flexed about 28 degrees. Arthroscopy has confirmed that cartilage loss occurs in a more posterior portion of the femoral condyles than is revealed by radiographs taken in full extension. The 'standing tunnel view' is a weight-bearing postero-anterior radiograph taken with the knee in 30 degrees of flexion. The radiographs of 64 patients have been used to compare the conventional with the standing tunnel view. In 10 knees in which the conventional view suggested normal cartilage the standing tunnel view revealed severe degeneration.     

综合手术治疗膝关节骨性关节炎合并膝内翻

目的 为使膝关节骨性关节炎合并膝内翻的年轻患者延缓行全膝关节置换,探讨股骨内髁马赛克植骨、髌骨成形并胫骨高位截骨综合手术治疗膝关节骨性关节炎合并膝内翻的临床疗效.方法 2004年6月-2006 年2月,对8例10膝骨性关节炎合并膝内翻患者行综合手术治疗.其中男2例3膝,女6例7膝;年龄42～56岁.左膝3例,右膝3例,双膝2例.患者均表现为行走或站久后疼痛.X 线片示股胫关节及髌骨边缘骨质增生,以内侧为重,髌股关节间隙变窄或消失,膝关节内侧间隙明显变窄.股胫角185～200°,平均 190°;HSS 膝关节评分为55～75分,平均60分.膝痛1～12年,平均5年. 结果 术后切口均Ⅰ期愈合,无早期并发症发生.患者均获随访7～24个月,平均15个月.患者截骨部位均于8～11 周达临床愈合,平均9周.股胫角矫正15～30°,平均 20°,基本恢复正常负重力线,膝关节外翻角 10°.术后关节活动度为 100～120°,较术前增加 5～20°,平均增加 10°.X 线片示膝关节内翻畸形基本纠正,截骨处无移位,内固定无松动、断裂.术后6个月HSS膝关节评分75～88分,平均80分. 结论 股骨内髁马赛克植骨使关节软骨得到一定程度的修复重建,髌骨成形有效解决膝前区疼痛,胫骨高位截骨矫正异常负重力线,三者结合,疗效肯定.     

Distribution of MR-detected cartilage defects of the patellofemoral joint in chronic knee pain

OBJECTIVES: The aim of the study was to detect cartilage defects and determine the center of these defects in MR imaging of the patellofemoral joint (PFJ) in middle-aged people with chronic knee pain. DESIGN: In the format of a prospective study of early osteoarthritis (OA), this cross-sectional study of the signal knee (the most painful one at inclusion in the study in 1990) in 59 individuals, 30 women and 29 men (aged 41-58 years, mean 50 years) with chronic knee pain, with or without radiographically determined knee OA, was examined using MR imaging on a 1.0 T imager. Cartilage defects and the center of these defects in the PFJ were recorded. RESULTS: Cartilage defects were found more often in the patella (40 knees) than in the femoral trochlea (23 knees) (P<0.001) and were unevenly distributed in the patella (P<0.001), with most cartilage defects in the mid-patella. CONCLUSIONS: Since cartilage defects occur more commonly in the mid-patella, radiographs obtained with a knee flexion of approximately 45 degrees may be more accurate to show cartilage defects of early OA of the PFJ than views with another knee flexion.     

The position of the popliteal artery in the arthritic knee.

We studied the position of the popliteal artery in 32 patients with primary osteoarthritis of the knee. A total of 45 knees were studied using a noninvasive technique with color-flow duplex scanning. The distance between the popliteal artery and the posterior tibial cortex was measured in various positions of flexion. The distance separating them was found to be maximal between 60 degrees and 90 degrees. The study was repeated in a smaller series of 17 patients (20 knees) after knee replacement but with less conclusive results. We believe the safest position on which to operate in primary arthroplasty is with the knee in flexion, but the safety margins are not the same in revision surgery.     

Fibroblast growth factor 2 in synovial fluid from an osteoarthritic knee with cartilage regeneration

 The levels of fibroblast growth factor 2 (FGF2) in synovial fluid of osteoarthritic knees were measured. The correlation between FGF2 and the severity of cartilage degeneration in varus-deformed knees with medial compartmental osteoarthritis or the articular cartilage regeneration that occurs after high tibial osteotomy (HTO) were investigated. Knees that underwent total knee arthroplasty (TKA) were categorized as either mildly or severely degenerated according to a modified Outerbridge's grading system for degeneration of articular cartilage. Regeneration of articular cartilage was observed in a biopsy specimen from the medial femoral condyle removed with the patient's consent during hardware removal approximately 2 years after HTO. The joint fluid FGF2 level was measured at that time using an enzyme-linked immunosorbent assay. Cartilage regeneration was classified as immature or mature according to the staging for regeneration of articular cartilage. The histological findings were analyzed using Pineda's evaluation method for cartilage regeneration. The mean concentration of FGF2 was 57.4 ± 17.6 pg/ml in the joint fluid from knees with severely degenerated cartilage. This was higher than the FGF2 concentration found in the mildly degenerated group. Approximately 2 years after HTO the FGF2 level in synovial fluid was lower in knees with mature regenerated cartilage than in those with immature regeneration. Osteoarthritic knees at a more mature regeneration stage had a lower Pineda's histological score. This result suggested that the FGF2 concentration in knees with osteoarthritis was influenced by articular cartilage degeneration and regeneration, and it correlated with the histological evaluation. Received: September 26, 2002 / Accepted: January 20, 2003 RID="*" ID="*" Offprint requests to: K. Orito     

The clinical consequences of flexion gap asymmetry in total knee arthroplasty

This study was carried out to compare femoral component rotation of 18 knees from 18 patients who suffered from lateral flexion instability after total knee arthroplasty (Western Ontario and McMaster University Osteoarthritis [WOMAC], 6.4 points; International Knee Society [IKS] score, 119 points) with 10 asymptomatic controls (WOMAC, 0.1 points; IKS score, 182 points) after total knee arthroplasty. The symptomatic patients showed increased lateral joint laxity as determined by fluoroscopic stress radiography. Femoral component rotation was determined by computed tomography scans. The femoral component rotation was more internally rotated in symptomatic patients (5.5 degrees ) than in controls (1.0 degrees ) (P = .04). Varus laxity in flexion was higher in symptomatic patients (11.0 degrees ) than in controls (7.0 degrees ) (P < .001). Increased lateral flexion laxity is associated with increased internal femoral component rotation and a less favorable clinical outcome.     

Simultaneous femoral osteotomy and total knee arthroplasty for treatment of osteoarthritis associated with severe extra-articular deformity

BACKGROUND: In the presence of large extra-articular deformity, complex imbalance of the collateral ligaments may result if standard techniques of soft-tissue releases and intra-articular bone resection are used during total knee arthroplasty. The purpose of this paper is to review our experience with simultaneous corrective osteotomy and total knee arthroplasty for the treatment of severe extra-articular femoral deformity associated with ipsilateral osteoarthritis of the knee. METHODS: The results of simultaneous corrective osteotomy and total knee arthroplasty in eleven knees with osteoarthritis and associated extra-articular angular deformity of the femur were reviewed retrospectively. The femoral deformity resulted from fracture malunion in ten knees and from hypophosphatemic rickets in one. There were five primarily uniplanar deformities (four varus deformities and one antecurvatum deformity), five biplanar (varus and antecurvatum) deformities, and one triplanar (varus, antecurvatum, and internal rotation) deformity. Four knees were approached through a standard medial parapatellar arthrotomy and seven, through an anterolateral subvastus approach with an osteotomy of the tibial tubercle. The site of the femoral osteotomy was fixed with a blade-plate in seven patients, a press-fit long-stemmed femoral component in two, and a retrograde femoral nail in two. An extramedullary alignment system was utilized in eight patients, and intramedullary alignment was used in three. RESULTS: The duration of follow-up averaged forty-six months (range, twenty-six to eighty-eight months). According to the classification system of the Knee Society, the mean function score increased from 22 points preoperatively to 81 points at the time of follow-up and the mean knee score increased from 10 points preoperatively to 87 points at the time of follow-up. The mean flexion contracture decreased from 19 degrees preoperatively to 2 degrees at the time of follow-up. The arc of motion averaged 56 degrees (range, 30 to 75 degrees) preoperatively and 89 degrees (range, 65 to 115 degrees) at the time of follow-up. The mechanical alignment in the coronal plane was restored to within 2 degrees of normal in each patient. Ten femoral osteotomy sites healed, and one, in a patient treated with a press-fit long-stemmed femoral component, had not healed by the time of follow-up. All seven sites of the tibial tubercle osteotomies healed. There were no complete radiolucent lines at the prosthetic interfaces, and no total knee arthroplasty was revised. One patient had a nonfatal postoperative pulmonary embolism. As determined by clinical examination and the patients' assessment of function, no ligament imbalance was noted at the time of the most recent follow-up. CONCLUSIONS: Simultaneous femoral osteotomy and total knee arthroplasty is a technically difficult but effective treatment for patients with severe femoral deformity associated with ipsilateral osteoarthritis of the knee. We recommend that the femoral osteotomy site be secured with a plate or a locked intramedullary nail, depending on the location of the deformity and the subsequent osteotomy.     

Articular cartilage lesions of the knee

The pathogenesis and clinical significance of articular cartilage lesions of the knee persist as topics of considerable interest among orthopedic surgeons. This study was designed to assess the association of articular cartilage degeneration with concomitant intraarticular abnormalities and to correlate the prevalence and severity of articular cartilage damage with preoperative historical and physical exam findings in patients presenting with knee pain. Twenty-six history and physical exam data points were prospectively collected from 192 patients (200 knees), consecutively undergoing arthroscopic knee surgery. During surgery, all articular cartilage lesions were recorded with respect to size, location, and character and were graded according to Oglivie-Harris et al. All concomitant knee joint abnormalities were simultaneously recorded. Of 200 knees examined arthroscopically, 12 knees revealed no demonstrable etiology for the presenting symptoms, 65 knees revealed assorted intraarticular pathology but no articular cartilage degeneration, and the remaining 123 knees revealed a total of 211 articular cartilage lesions (103 femoral, 72 patellar, 36 tibial); 7 femoral, 6 patellar and 0 tibial lesions were completely isolated (no concomitant knee joint pathology). The concomitance of femoral defects with tibial lesions was highly significant (p = 0.01). Femoral and tibial articular cartilage lesions were strikingly correlated with the presence of an unstable torn meniscus (p less than 0.001). Medial compartment articular cartilage lesions were significantly more common (p = 0.001), more closely associated with meniscal derangement, and appreciably more severe than lateral compartment lesions. In 75% of anterior cruciate ligament-deficient knees with concomitant articular cartilage degeneration, the duration from injury to surgery was greater than 9 months, and in each of these cases, a history of reinjury to the knee was elicited. From these data one can conclude that: (a) in some patients with painful knees, isolated articular cartilage lesions may be the only abnormality noted at arthroscopy; (b) unstable meniscal tears are significantly associated with destruction of articular cartilage; (c) the medial compartment is particularly susceptible to articular cartilage degeneration; and (d) in our series, anterior cruciate ligament tears were increasingly associated with articular cartilage destruction as the elapsed time from injury to arthroscopy increased.     

Total knee arthroplasty without patellar resurfacing in isolated patellofemoral osteoarthritis

Thirty-one patients (33 knees) with symptomatic patellofemoral osteoarthritis and minimal tibiofemoral changes underwent LCS total knee arthroplasty without patellar resurfacing. Average age was 73 years (range, 58-89 years) with a female-to-male ratio of 5:1. Average follow-up was 20 months (range, 12-40 months). All except 4 patients had grade 3 or 4 patellofemoral osteoarthritis. Preoperatively, all patients had significant knee pain. Sleep disturbance was reported in 21 patients. All but 10 patients required walking aids. Average range of motion was 108 degrees (range, 80-125 degrees ). At latest review, 21 knees were pain-free, the remaining 12 knees being described as having only occasional knee pain. Two patients continued to have night pain. Average range of motion was 104 degrees (range, 70-135 degrees ). Lateral patellar tilt improved in all but 5 knees by an average of 7 degrees (range, 1-26 degrees ). Patellar congruency improved in all but 3 knees by an average of 18% (range, 3-63%). None of the patients to date have required revision surgery. Total knee arthroplasty without patellar resurfacing is an effective option in older patients with isolated patellofemoral osteoarthritis.     

A comparison of 4 intraoperative methods to determine femoral component rotation during total knee arthroplasty

A total of 100 consecutive posterior cruciate-retaining total knee arthroplastics were performed in 81 patients with an average age of 69 years by 1 surgeon. Diagnoses included osteoarthritis in 93 knees and rheumatoid arthritis in 7 knees. The femoral alignment necessary to create a rectangular flexion gap was determined and compared with Whiteside's line, the transepicondylar axis, and a line in 3 degrees of external rotation relative to the posterior condyles of the femur. The transepicondylar axis most consistently recreated a balanced flexion space, whereas 3 degrees of external rotation off the posterior condyles was least consistent, especially in valgus knees.     

Distribution of bone mineral density at the proximal tibia in knee osteoarthritis

One hundred and thirteen knees with osteoarthritis (OA) were studied to assess the distribution of bone mineral density (BMD) in the proximal tibia and the potential relation between osteoarthritis and osteoporosis in evaluating hip BMD. All patients had severe knee pain and were diagnosed with Kellgren and Lawrence grade IV osteoarthritis. According to the magnitude of the axial deformity, four categories were created: varus>10 degrees ( 28.3%), varus 4-10 degrees (38.9%), aligned 180 +/- 3 degrees (13.3%), and valgus>4 degrees (19.5%). For each category, the medial and lateral proximal tibial density were assessed. BMD was measured at the femoral neck and at 14 regions of interest (ROI) in the proximal part of the tibia using dual X-ray absorptiometry. Based on the femoral neck BMD, patients were classified according to the World Health Organization (WHO) definition of osteoporosis. The mean knee BMD was positively correlated with the hip BMD value (knee BMD m = 0.38 + 0.73 x hip BMD, r = 0.60, P<0.001). The knee BMD distribution of the 113 patients was negatively correlated with the axial deformity (BMD MT-LT = 5.15 - 0.027 x HKA, r = 0.77, P<0.0001). In the varus deformity, BMD of the medial side was higher than that of the lateral side with an important asymmetry (0.587 g/cm2). This asymmetry was also found in the valgus deformity for the lateral side but was less important (-0.112 g/cm2). With equal deformity, the asymmetry of BMD was higher in varus deformity (0.587 g/cm2) than in valgus deformity (-0.112 g/cm2). Asymmetry of the knee BMD distribution revealed that progression of the deformity (either varus or valgus) with joint space narrowing led to an increase in the medio-lateral difference of the proximal tibia density. Lesser severity of Kellgren and Lawrence grades may reveal different results. Twenty patients with osteoporosis developed knee osteoarthritis (OA) and the relation between osteoporosis and knee OA remains unclear.     

Tibial subchondral bone size and knee cartilage defects: relevance to knee osteoarthritis

Unlike knee plain radiography which can only detect joint space narrowing and osteophytes, magnetic resonance imaging can directly visualize and analyse the whole knee structure, including bone size, cartilage defects and loss of cartilage volume. Tibial subchondral bone area expansion may be primary and is associated with risk factors such as age, body mass index (BMI), genetics and/or limb malalignment. It can lead to the development of knee defects, which may also be caused by demographic, anthropometric and environmental factors such as age, female sex, BMI and smoking as well as structural changes such as osteophytes, bone marrow lesions, meniscal tears, meniscal extrusion and ligament abnormalities. Once knee cartilage defects develop, they have a variable natural history but are associated with subsequent cartilage loss in a dose-response manner. Both tibial subchondral bone area and knee cartilage defects are quantitatively related to the severity of knee osteoarthritis (OA), and predictive of the need for knee joint replacement in subjects with knee OA independent of radiographic change. Taken as a whole, these studies suggest that tibial subchondral bone expansion and cartilage defect development represent important targets for the prevention of cartilage loss and joint replacement.     

Osteonecrosis of the knee: Diagnosis and outcome in 40 patients

Clinically suspected primary osteonecrosis of the knee was studied in 40 patients with repeated plain radiography and scintimetry, and the patients were followed for 1-7 years. Thirty-three patients had typical scintimetric and radiographic signs of osteonecrosis of either one of the femoral condyles, whereas 7 patients had only typical scintimetric findings, but never developed an osteonecrosis based on plain radiography. Because the scintimetric findings were identical to the other 33 knees and because there is no other well-known localized disease in this region of the femoral condyle, we deemed that these 7 patients had probable osteonecrosis, but in an abortive form.

The scintimetries were prognostic during the second half year after onset. Thirty knees had a poor outcome-29 because of development of arthrosis, of which eight were treated with a knee arthroplasty and four with a proximal osteotomy.     

Osteoarthritis of the Knee in the Rabbit Produced by Immobilization:: Attempts to Achieve a Reproducible Model for Studies on Pathogenesis and Therapy

In order to obtain a reproducible experimental model of osteoarthritis a method of immobilizing the rabbit's knee in extension by means of a plastic splint was developed. The right knees of the rabbits were immobilized for periods varying from 4 days to 24 weeks. With the left knees as controls the knees were studied in a variety of ways among these being radiography (126 rabbits), histological sections stained with Alcian Blue (88 rabbits), analysis of ³⁵S-sulphate uptake (22 rabbits) and ³⁵S-autoradiography (6 rabbits). In 27 rabbits the regaining of mobility after immobilization was studied. After 5-6 weeks of immobilization most of the knees showed moderate or severe changes including loss of articular cartilage and osteophyte formation. Immobilization of the rabbit's knee by this method provokes a fairly easily reproducible type of degenerative joint disease showing similarities to advanced osteoarthritis as seen in humans.     

Component rotation and anterior knee pain after total knee arthroplasty.

All patients undergoing cruciate-retaining primary total knee arthroplasty for degenerative osteoarthritis at one center were studied prospectively. Clinical and radiographic followup was obtained at a minimum 5 years in 102 knees in 73 patients. Patients were asked specifically about the presence of the pain in the anterior aspect of the knee in the vicinity of the patella and rated the severity of the pain on a visual analog scale. Significant anterior knee pain rating at least 3 of 10 on the visual analog scale was present in 16 knees (13 patients). Eleven patients with 14 symptomatic knees agreed to undergo computed tomography scanning to accurately determine the rotation of the tibial and femoral components. The epicondylar axis and tibial tubercle were used as references using a previously validated technique. A control group of 11 asymptomatic patients (14 knees), matched for age, gender, and length of followup also underwent computed tomography scanning. All patients in both groups had normal axial alignment. There was a highly significant difference in tibial component rotation between the two groups with the patients with anterior knee pain averaging 6.2 degrees internal rotation compared with 0.4 degrees external rotation in the control group. There also was a significant difference in combined component rotation with the patients with anterior knee pain averaging 4.7 degrees internal rotation compared with 2.6 degrees external rotation in the control group. There was no significant difference in the degree of radiographic patellar tilt or patellar subluxation between the two groups. Patients with combined component internal rotation were more than five times as likely to experience anterior knee pain after total knee arthroplasty compared with those with combined component external rotation. Component malrotation is a significant factor in the development of anterior knee pain after total knee arthroplasty.     

Bone anatomy and rotational alignment in total knee arthroplasty

The purpose of the current study was to investigate the bone anatomy in determining the rotational alignment in total knee arthroplasty using computed tomography. Axial images of 109 knees in 83 patients with varus osteoarthritis who had total knee arthroplasty were analyzed. On the images of the distal femur and the proximal tibia, a baseline for the anteroposterior axis of each component was drawn based on the epicondylar axis for the femur and the medial (1/3) of the tibial tuberosity for the tibia. The angle between these two lines was analyzed as the rotational mismatch between the components when they were aligned to the anatomic landmarks of each bone. Fifty-four knees (49.5%) had an angle of 5 degrees or greater and 13 knees (11.9%) had an angle of 10 degrees or greater. There was a tendency to align the tibial component in external rotation relative to the femoral component. The results indicated that the landmarks of each bone were the intrinsic cause of the rotational mismatch in knees with varus osteoarthritis. Surgeons doing total knee arthroplasties should be aware of this and check the rotational mismatch between the components. When it is present, the tibial component should be realigned to match the femoral component rotation to minimize problems caused by the mismatch.     

Characteristics of degeneration in an unstable knee with a coronal surface step-off

To investigate the effect of instability on the remodelling of a minor articular surface offset, we created a 0.5 mm coronal step-off of the medial femoral condyle in 12 New Zealand white rabbits and transected the anterior cruciate ligament (ACL). A control group of 12 rabbits had only ACL resection and the opposite knee was used as the non-operated control. The osteoarthritic changes at 6, 12 and 24 weeks after surgery were evaluated histologically. In addition, changes in the immunological detection of 3-B-3(-) and 7-D-4 chondroitin-6-sulphate epitopes were determined because of the previous association of such changes with repair of cartilage and early osteoarthritis. In the instability/step-off group there was rapidly progressing focal degeneration of cartilage on the high side of the defect, not seen in previous step-off studies in stable knees. The rest of the femoral condyles and the tibial plateaux of the instability/step-off group had moderate osteoarthritis similar to that of the instability group. 3-B-3(-) was detectable in the early and the intermediate stages of osteoarthritis but no staining was seen in the severely damaged cartilage zones. Immunoreactivity with 7-D-4 increased as degeneration progressed.     

计算机导航全膝关节置换术在创伤后股骨干严重畸形患者中的应用

目的介绍计算机导航辅助全膝关节置换术（TKA）在伴有关节外股骨严重畸形患者中的应用.方法 回顾分析了在2005年1月至2010年为5月间,我院共收治了伴有股骨严重畸形的单侧膝关节骨性关节炎患者6例,在计算机导航辅助下进行了人工全膝关节置换术.结果平均随访27个月.术前膝评分平均10分,膝功能评分平均22分.术后膝评分平均85分,膝功能评分72分.术后下肢力线偏差均在3°以内.无患者出现导航相关并发症.结论对于伴有严重关节外畸形的患者,计算机导航全膝关节置换术不需要进行股骨、胫骨截骨,手术创伤相对较小,术后患者恢复快.对此类患者计算机导航全膝关节置换术具有良好的适应证.     

Distal femoral osteotomy for valgus deformity of the knee.

Distal femoral varus osteotomy and blade-plate fixation for valgus deformity of the knee proved effective in restoring axial alignment in 18 of 36 knees (34 patients). Patients were followed for an average of 5.4 years (range: 2 to 19 years). The osteotomies were performed on 14 men and 22 women (average age: 44 years; range: 14 to 77). The patients' average preoperative valgus deformity of the anatomical axis was 19.4 degrees (range: 8 degrees to 33 degrees). The surgical procedures performed were a medial closing wedge osteotomy (14 knees) and a lateral opening wedge osteotomy with bone grafting (22 knees). Postoperative correction of the anatomical axis averaged 3.8 degrees valgus (range: 8 degrees varus to 20 degrees valgus). Maximum improvement was reached within 6.3 months by patients who were less than 60 years old and within 5.1 months by patients who were more than 60 years old. Pain decreased or resolved in 21 of 35 knees (60%); activity level improved in 24 of 35 knees (69%). One patient was unavailable for follow up evaluation. Varus osteotomy in the distal femur was concluded to be an acceptable form of treatment in the valgus knee alone or associated with traumatic or osteoarthritis of the lateral compartment.