Surgical Biomechanics of the Patellofemoral Joint

This review presents objective data, as far as possible, about the current understanding of the biomechanics of the patellofemoral joint as it pertains to the management of patellofemoral problems. When faced with a patellofemoral malfunction, it is important to check all the soft-tissue and articular geometry factors relating to the patella locally and not to neglect the overall lower limb alignment and function. It is important to remember that small alterations in alignment can result in significant alterations in patellofemoral joint stresses and that changes in the mechanics of the patellofemoral joint can also result in changes in the tibiofemoral compartments. Surgical intervention for patellofemoral problems needs to be planned carefully and take into account an individual’s anatomy.     

关节镜下人工韧带重建前交叉韧带的临床初步体会

目的探讨关节镜下应用LARS人工韧带重建前交叉韧带的可行性及近期疗效. 方法用法国产LARS人工韧带对16例前交叉韧带(anterior cruciate ligament,ACL)损伤行关节镜下ACL重建术.等距点钻胫骨、股骨骨道,将肌腱拉入骨道,韧带游离部分位于关节腔内,拉紧后2枚螺钉固定韧带,合并损伤同期处理. 结果手术时间51～86 min,平均64 min.术后无滑膜炎、韧带断裂、活动明显受限等并发症.16例均随访1.5～6个月,平均3.8月.按照IKDC评分标准:术前C级6例,D级10例;术后A级6例,B级9例, C级1例(χ2=6.264,P<0.05).Lysholm膝关节功能评分术前36～76分,(63.7±7.3)分;术后86～97分,(94.8±9.6)分(t=10.356,P<0.05). 结论关节镜下LARS人工韧带重建ACL,操作简便,可使膝关节获得即时稳定性,早期康复锻炼,最大限度的防止关节功能受限,近期疗效满意.     

Tissue-sparing surgery with the bi-unicompartmental knee prosthesis: retrospective study with minimum follow-up of 36 months

Despite its theoretical advantages in terms of less invasive surgery, bi-unicompartmental knee replacement still represents a controversial knee reconstructive procedure. Many orthopaedic surgeons are skeptical about this demanding procedure despite the possibility of maximally preserving anatomy, with benefits for functional aspects such as gait, muscle activity and proprioception. Presently, no results of bi-unicompartmental knee replacement have been reported in the literature, even if several surgeons use it in selected cases. We present a retrospective analysis of our experience with this implant at a minimum follow-up of 36 months. At the latest follow-up, the mean Knee Society score was 80.58, the mean functional score was 83.5 and the mean postoperative GIUM score was 78. No implant has been revised and all patients are satisfied with the outcome. We consider bi-unicompartmental knee replacement to be a reasonable, less invasive option for the treatment of knee arthritis in selected cases.     

The patella and tibial condyle position after combined and after closing wedge high tibial osteotomy

High tibial osteotomy changes the patella and tibial condyle position, which makes the subsequent total knee replacement technically demanding. From 1 January 1993 to 31 December 2000, combined osteotomy [After the first osteotomy made 2 cm distally to the joint line, a bone wedge is removed based laterally. Its tip ends at the center of the tibial condyle (half bone wedge). The distal part of the tibia is placed into the valgus position and the half bone wedge is placed into the gap opened medially.] was performed on 103 knees and closing wedge osteotomy was performed on 47 consecutive knees. Eighty combined (group A) and 41 closing wedge (group B) osteotomy were studied. All knees were assessed radiologically before surgery, in the 10th postoperative week, in the 12th postoperative month and at the time of the final follow-up (in group A—66.15 months, in group B—66.61 months). We examined the change of the femorotibial angle, of the patellar height according to the method of Insall and Salvati, of the tibial slope angle according to the method of Bonnin, of the tibial condylar offset according to the method of Yoshida and of the distance between the lateral tibial plateau and the top of the fibular head. In group A and B, the recurrence of the varus deformity was not noted and valgus alignment did not increase in any case. In group-A, the Insall–Salvati ratio remained unchanged in 65% of knees. The tibial slope angle decreased in both groups. There was correlation between the change of the tibial condylar offset and the angle of the correction in both groups. There was correlation between the change of the distance between the lateral tibial plateau and the top of the fibular head. After combined osteotomy, the transposition of the tibial condyle and the decrease of the distance between the lateral tibial plateau and the top of the fibular head was less than after closing wedge osteotomy, although the average angle of correction was more after combined osteotomy (11.835°), than after closing wedge osteotomy (9.465°). Theoretically, the recurrence of the varus deformity, the increase of the valgus alignment and (in majority of cases) the shortening of the patellar tendon do not compromise the likelihood of successful conversion to the subsequent total knee replacement, either after combined or after closing wedge osteotomy. The combined osteotomy does not lead to considerable transposition of the tibial condyle and to considerable lateral tibial bone loss; therefore, theoretically, the combined osteotomy does not impair the subsequent total knee replacement.     

Surgical treatment of multiple knee ligament injuries in 44 patients: 2–8 years follow-up results

The purpose of the study was to evaluate the mid-term results of surgical treatment in different groups of patients with multiple knee ligament injuries. Review of our patients’ records revealed that 48 acute and chronic patients were surgically treated for combined knee injury. Due to severe capsular damage in these injuries, open techniques were used. In our treatment protocol, avulsed ligaments and tears of the posterolateral and posteromedial corner were repaired if possible, whereas midsubstance tears of cruciate ligaments and chronic cases were reconstructed with autografts. Postoperatively, an accelerated program of rehabilitation was introduced, aiming to progressively mobilize the joint and improve muscle endurance. For the follow-up evaluation we designed a protocol composed of two parts. In the first part, anatomical lesions were recorded and in the second part, clinical evaluation was performed using the Lysholm score, the Tegner rating system, the IKDC evaluation form, and the KT1000. Student’s t tests and chi-square tests were used for data analysis. Forty-eight patients (mean age 28.6±11.9 years; 41 males) were classified according to the specific anatomical structures involved. Group A included 12 anterior cruciate ligament (ACL) and medial structure injuries, group B included 11 ACL or posterior cruciate ligament (PCL) ruptures combined with posterolateral injuries, and group C consisted of 25 knee dislocations (ACL and PCL ruptures which might be combined with damage of the collateral ligaments). Thirty-eight patients were surgically treated during the acute phase and ten patients were treated chronically. Forty-four patients (91.6%) were followed up at a mean of 51.3±29.9 months. Average Lysholm score was 87±12.3; average Tegner score was 5.09±2.19 before accident and 4.34±2.12 in re-examination; IKDC score was A in 10 cases, B in 22, C in 6, and D in 6. The mean range of motion was 129.9°±12.5°. The average loss of extension and flexion were 1.6°±2.5° and 7.6°±7.9°, respectively. The side-to-side difference in corrected anterior and posterior translation in quadriceps neutral angle and in anterior translation in 30° angle was <3 mm for about 65% of our patients. Surgical treatment of multiple knee ligament injuries, using autografts, provided satisfactory stability, range of motion, and subjective functional results. However, despite the improvement of the quality of life, the preinjury patients’ activity level was not fully obtained in re-examination. Patients underwent surgical treatment during the acute phase had better scores in several points, but finally there was no statistical significance between acute and chronic patients. Moreover, no statistically significant differences were observed among the groups with specific damaged anatomical structures.     

成人正常股骨解剖测量及其在膝关节置换的临床意义

[目的]为膝关节置换准确截骨和获得良好的下肢力线，对中原地区成人股骨干进行相关测量。[方法]（1）选取47根成人正常股骨标本，拍摄正、侧位数码照片，进行定点、划线、测量五角。（2）实体上确定股骨髓内定位杆进针点的位置：[结果]（1）各角度值反映了股骨远端在冠状位和矢状位的解剖形态。（2）进针点与股骨滑车中心水平距离平均为6．21mm，与后交叉韧带止点前缘距离平均为6．70mm。[结论]（1）股骨远端1／3段与股骨近端1／3段向外侧、前侧成角，且前倾角度大于外翻角度。所以股骨远端在决定股骨髓内定位杆的位置时，冠状面上的力线对位和矢状面上的对位均很重要。（2）全膝关节置换术中确定进针点可参考股骨滑车中心和股骨髁后交叉韧带止点的位置。