Electronic measurement of soft-tissue balancing reduces lateral releases in total knee arthroplasty

Soft tissue balancing during total knee arthroplasty (TKA) has a direct affect on patello-femoral tracking and knee range of motion, which are necessary for a well functioning TKA postoperatively. We report on the use of an electronic pressure sensing instrument for soft tissue balancing of the knee before completion of all intraoperative bone cuts, as a way to improve patellar tracking. In a retrospective study of 99 consecutive TKAs, with intraoperative electronic instrument guided soft tissue balancing performed, a reduction in the incidence of lateral patellar retinacular release was found, as compared with the 100 consecutive TKAs prior to its use (5.5% v 12%, respectively). Electronic measurement of soft tissue balancing during TKA reduced the need for lateral patellar retinacular release.     

The Elmslie-Trillat procedure for recurrent patellar subluxation after total knee arthroplasty

Patellofemoral problems are the most common complications after total knee arthroplasty (TKA). We report a patient who had patellar subluxation twice within 7 months after primary TKA. Postoperative radiographs and computed tomography scans revealed a valgus knee with no evidence of malposition of the prostheses. To eliminate the recurrent patellar subluxation, we finally performed an Elmslie-Trillat procedure in combination with extensive lateral release and succeeded in achieving normal patellar tracking. At 1-year postoperative follow-up, the patient was satisfied with the results. The patella tracked well in the femoral trochlear groove during knee flexion after the revision surgery. This procedure, in combination with lateral release, should be considered as a useful surgical treatment that can eliminate patellar subluxation after TKA in cases without component malposition.     

Prospective analysis of Sheehan total knee arthroplasty

In a prospective study, the clinical results of 64 Sheehan total knee arthroplasties (TKA) were reviewed in 52 patients, with an average follow-up period of five and one-half years. Like most prosthetic designs in use in 1975, the Sheehan prosthesis did not incorporate patellar resurfacing. The initial clinical success achieved without patello-femoral replacement may become less acceptable with longer follow-up periods. Seventy-four percent of the patients in this study had complete relief of pain or mild discomfort not requiring analgesics. With patellar resurfacing as a secondary procedure in three additional cases, the percent successful results increased to 81%. Five knees (12%) required additional surgery, one because of infection, two because of secondary component failure, and two for loosening. The lack of patellofemoral replacement and prospective failure of both tibial and femoral components, possibly due to high stress-loading in a relatively small surface area, have led to the use of other newer TKA designs.     

Patella in total knee arthroplasty

The patella is a reliable guide to the success or failure of a total knee replacement. Patients who do not experience peripatellar symptoms or a patellar complication usually have a successful result. Conversely, peripatellar symptoms or complications usually reflect an underlying problem with surgical technique, component designs, or both. Current designs still do not replicate normal kinematics, and current instrumentation and techniques significantly alter the anatomy of the patellofemoral articulation in a substantial percentage of patients. Reproducing extensor mechanism balance and using components that provide adequate congruency and contact area through a physiologic arc of motion should lead to a successful result with minimal patellar symptoms or complications whether or not the patella is resurfaced. Attempting to achieve normal patellofemoral kinematics and minimize patellar complications has led to a better understanding of total knee arthroplasty.     

Management of periprosthetic patellar fractures. A systematic review of literature

Despite advances in surgical technique and implant design, complications involving the extensor mechanism and patellofemoral joint after total knee arthroplasty (TKA) continue to be the most common cause of pain and the most commonly cited reason for revision surgery. Periprosthetic patellar fractures occur in 1.19% of all reported cases after TKA, with a clear correlation with resurfacing of the patella. In 88.32% of the cases reported the fracture is not associated with a traumatic event and it is identified at the follow-up examination during the first 2 years after knee replacement. Predisposing factors for fracture include lateral release, excessive bone removal, peg fixation and cementation, improper patellar tracking and prosthesis malpositioning. More than 50% of fractures are associated with a loose implant which complicates the fracture management. Non-operative treatment seems to offer acceptable functional results and pain relief, especially in cases of minimal displacement and stable implant fixation. However, when surgical reconstruction is undertaken, open reduction and internal fixation with tension band or cerclage wiring should not be the first choice of treatment as the rate of failure and subsequent non-union may be as high as 90%.     

The influence of component alignment on patellar kinematics in total knee arthroplasty

Background and purpose — Postoperative anterior knee pain is one of the most frequent complications after total knee arthroplasty (TKA). Changes in patellar kinematics after TKA relative to the preoperative arthritic knee are not well understood. We compared the patellar kinematics preoperatively with the kinematics after ligament-balanced navigated TKA.

Patients and methods — We measured patellar tracking before and after ligament-balanced TKA in 40 consecutive patients using computer navigation. Furthermore, the influences of different femoral and tibial component alignment on patellar kinematics were analyzed using generalized linear models.

Results — After TKA, the patellae shifted statistically significantly more laterally between 30° and 60°. The lateral tilt increased at 90° of flexion whereas the epicondylar distance decreased between 45° and 75° of flexion. Sagittal component alignment, but not rotational component alignment, had a significant influence on patellar kinematics.

Interpretation — There are major differences in patellar kinematics between the preoperative arthritic knee and the knee after TKA. Combined sagittal component alignment in particular appears to have a major effect on patellar kinematics. Surgeons should be especially aware of altering preoperative sagittal alignment until the possible clinical relevance has been investigated.     

The patellofemoral component of total knee arthroplasty

Patellofemoral complications continue to form a large proportion (up to 50%) of total knee arthroplasty (TKA) complications. If adequate attention is paid intraoperatively to patellar tracking and component position, the incidence of subluxation, component loosening, and fracture should decrease. When treating patellar subluxation and dislocation, tibial tubercle transfer should be avoided because there is an unacceptably high incidence of complications. Care should be taken to treat the underlying cause of dislocation with either a soft tissue procedure or component revision. Fracture of the patella may be treated nonoperatively in 50% and 80% of patients. Cysts, if large, may be bone-grafted to avoid the potential complications of stress fracture and component loosening. Loosening of the patellar component is likely to be symptomatic and to require surgery in up to 75% of cases. A displaced patellar component may cause attritional wear of the quadriceps tendon or patellar ligament. All rheumatoid patellae should be resurfaced. The present trend in the osteoarthritic patella is toward resurfacing more often. With improved implant design and a predicted decrease in complications, resurfacing in the osteoarthritic patella may become routine. Osteoarthritic patellae that maintain good cartilage, normal anatomic shape, and congruent tracking need not be resurfaced.     

Influence of Total Knee Arthroplasty on Patellar Kinematics and Patellofemoral Pressure

Background

Patellofemoral complications are one of the main problems after total knee arthroplasty (TKA). The design of the TKA component may affect the patellar biomechanics, which may be associated with this postoperative complication. The purpose of this study was to assess the influence of TKA and prosthesis designs on the patellar kinematics and patellofemoral pressure.

髌骨钻孔减压改善全膝关节置换术后膝前疼痛

目的探讨通过髌骨钻孔减压术改善全膝关节置换术(TKA)后膝前痛的临床疗效。方法将符合标准的113例行TKA的骨关节炎患者按数字法随机分为两组:54例为减压组,TKA术中联合髌骨钻孔减压术;59例为非减压组,仅施行TKA不联合髌骨钻孔减压术。术后观察两组患者切口愈合情况、相关并发症、KSS评分及膝前痛发生率。结果两组患者切口均一期愈合,无严重并发症发生,113例均获满12个月的完整随访。KSS评分:减压组术后明显高于非减压组;术后膝前痛的发生率明显低于非减压组,差异均有统计学意义(P0.05)。结论 TKA术中联合髌骨减压术可以在一定程度上改善膝关节KSS评分及降低术后膝前疼痛的发生率。     

Kinematic total knee arthroplasty: a 10- to 14-year prospective follow-up review.

To understand better the type and incidence of long-term complications in total knee replacement, 306 primary Kinematic total knee arthroplasties performed between June 1978 and December 1982 were prospectively reviewed in detail. The Kinematic knee is a nonconstrained, posterior cruciate-retaining prosthesis that has right and left femoral components to afford anatomic tracking of the patella. The overall revision rate was 6.5%. The most common cause for revision surgery was patellar complications. Ten revisions (3.06%) were for patellar component loosening. Two knees were revised for patella subluxation (0.65%); 1 was in a resurfaced rheumatoid patella, and 1 in an unsurfaced osteoarthritic patella. Stair climbing was better with an unsurfaced patella. Anterior knee pain was 21.8% in the unsurfaced patella and 11.2% in the replaced patella. These data suggest patella replacement is not appropriate with this design.     

Postoperative patellar complications with or without lateral release during total knee arthroplasty

Between 1975 and 1984, 84 knees in which an intraoperative lateral release had been performed with total knee arthroplasty (TKA) were compared with 471 knees that, having sufficient patellar tracking at the time of surgery, had not required a lateral release. The lateral superior geniculate artery was routinely sacrificed in all knees in which a lateral release was necessary. The results showed no complications associated with a possible loss of blood supply secondary to the lateral release. No increased evidence of osteonecrosis, patellar bone-cement radiolucency, or patellar fracture was discovered. Clinically, there was no difference in pain, ambulation, or range of motion. Seventeen patellar fractures (3.6%) were observed in patients for whom a lateral release had not been performed, yet only one patellar fracture (1.5%) was encountered among the patients who had required a lateral release. In TKA, lateral release was associated with a relatively high degree of patellar tilting.     

Patellofemoral resurfacing at total knee arthroplasty

A retrospective review of 268 primary total knee arthroplasties (TKAs) with a mean follow-up of four years is presented. The patellae were resurfaced in all cases. There were six complications (2.2%) referable to the patellofemoral articulation: three subluxations, one patellar fracture, one loosening of a metal-backed patellar component, and one patellar tendon avulsion. Successful patellofemoral resurfacing (PFR) can be accomplished with minimal complications if the following technical considerations are met: 5-7 degrees of valgus alignment; medial placement of the patellar component; taking care not to increase either the AP diameter of the knee or the thickness of the patella; avoiding internal rotation of either the tibial or femoral components and proper soft tissue balancing. A thorough review of patellofemoral complications after TKA is presented, and technical considerations relevant to the successful performance of PFR are discussed.     

髌骨合理设计在全膝关节置换中的临床效果

目的探讨髌骨合理设计后重塑在全膝关节置换(TKA)中的临床效果。方法根据股骨假体滑动轨迹及所需置换髌骨的形态,对56例TKA患者(72膝)术中进行髌骨合理设计并重塑,观察患者术后的关节活动度及疼痛情况,用KSS膝关节评分系统评定治疗效果。结果 56例均获得随访,时间6~18个月。仅1例患者膝关节活动度70°,活动较差,但疼痛明显减轻;其余患者屈曲活动度在0°~110°。KSS评分:优69膝,良2膝,中1膝,优良率达到98.6%。结论术中根据股骨假体滑动轨迹对髌骨合理设计并重塑,可以使未进行髌骨置换的TKA患者取得满意的治疗效果。     

小腿开放伤术后重度感染1例

患者,男,46岁,2011年3月11日因“外伤致左小腿出血、疼痛4h”入院.入院查体：左小腿中下段前外侧见1个“V”形裂口,长约9 cm,皮缘挫伤重,出血,污染,创口内见腓浅神经裸露、挫伤,部分肌肉挫裂,足背侧皮肤感觉减退,踝、趾关节活动可,足背动脉搏动可及（图1a）.患者合并高血压与糖尿病,完善相关检查后急诊在硬膜外麻醉下行清创探查缝合术.术中可见：创口深约1指,由外下方通达腓骨后上部,腓浅神经挫伤、裸露,连续性存在,趾长伸肌大部分,拇长伸肌、胫前肌部分及腓骨长短肌部分肌束挫裂,腓骨部分皮质外露;创口组织内粘附大量泥沙样污染物.术中延长创口,清除污染物和挫灭组织,双氧水盐水反复冲洗,碘伏消毒,肌肉部分修复,置皮片引流,关闭创口.术后常规抗感染活血补液对症治疗.术后24 h患者出现高热（体温39.5℃）,畏寒,左小腿弥漫性红、肿、疼痛,创口渗液,脓性,灰白色,伴腐恶臭,创口周缘局部出现坏死表现,皮肤色加深、发黑,创缘皮肤按压有捻发感（图1b）.     

Lateral retinacular release during primary total knee arthroplasty: effect on outcomes and complications

Intraoperative lateral retinacular release performed during primary total knee arthroplasty (TKA) can improve patellar tracking. This study compares the outcomes of patients who did and did not have lateral retinacular release during primary TKA. One thousand one hundred eight consecutive primary TKAs were reviewed. Lateral release was performed on 314 patients; 794 patients did not undergo release. Comparisons of range of motion, Knee Society Score, and postoperative complications were made between the 2 groups. At an average follow-up of 4.7 years, no statistically significant difference in range of motion, Knee Society Score, or postoperative complications of patella fracture, subluxation, postoperative manipulation, or wound complications was demonstrated. Lateral retinacular release to achieve improved patellar tracking does not compromise the clinical outcomes or complication rate of primary TKA.     

初次全膝关节置换术后膝前痛预防的研究进展

全膝关节置换术（total knee arthroplasty,TKA）是治疗终极膝关节病变的有效方法,能有效缓解疼痛,纠正畸形,改善功能,进而提高患者的生活质量.目前,患者的满意程度越来越被认为是评价TKA的一个重要因素.而膝前痛作为初次TKA后的常见并发症,是指发生于膝前或者髌骨周围的疼痛,这严重影响了患者膝关节功能的改善和其对手术的满意程度.因此,膝前痛的减轻成为TKA的重要目标.目前,认为膝前痛的主要机制是髌股关节的高接触应力造成的软骨下骨内压升高和并发于髌骨运行轨迹异常导致的髌骨周围软组织病变.近年来针对如何预防全膝关节置换术后膝前痛的发生进行了大量研究,但是由于各种各样的原因,至今为止不管是髌骨置换,保留髌骨行髌骨周围去神经化,还是活动平台体都不能取得确切而良好的效果.由此可见,初次TKA后膝前痛的防治仍然是一个棘手的问题.此问题的解决,需要对膝前痛发生原因、膝关节假体及髌股关节生物力学特性做进一步研究,并经过大规模的随机对照试验的论证.     

Optimizing patellofemoral tracking during total knee arthroplasty

Fifty-seven patients who underwent 65 primary TKAs between 1993-1994 were retrospectively studied to identify the technical challenges and pitfalls associated with patellar resurfacing and to improve patellar tracking during total knee arthroplasty (TKA). Average patient age was 69 years. All surgeries were performed by a single surgeon (J.N.I), and the same prosthesis was used in all patients. Intraoperatively, attention was paid to avoid femoral and tibial component malrotation and prevent overstuffing of the patellofemoral joint. Preoperative limb alignment was varus in 42 knees, neutral in 6 knees, and valgus in 17 knees. Average pre-resection patellar thickness measured 23.8 mm and post-resection thickness averaged 21.5 mm. No patella-prosthesis composite was thicker than the native patella. Two (3%) knees required a formal lateral release to improve patellar tracking at surgery. Average follow-up for 53 patients (61 knees) was 5 years. At latest follow-up, 4 (6%) patients reported mild anterior knee pain, 5 (7%) patients reported pain with stairs, and 2 (3%) patients had knee crepitus without pain. No dislocations or recurrent subluxations occurred. No patient required revision surgery for patellofemoral complication. Awareness of the anatomic variability, attention to component rotation, and restoration of the normal patellar height improves patellar tracking and minimizes patellofemoral instability following TKA.     

Influence of total knee arthroplasty on patellar kinematics and contact characteristics

Purpose  

Femoro-patellar complications are one of the most common problems after total knee arthroplasty (TKA). TKA components that reduce patellar loads and preserve physiological patellar kinematics should reduce these problems. Therefore, we evaluated the patellar kinematics and the retro-patellar contact characteristics in both the intact knee and in the TKA-knee.     

Partial Lateral Patellar Facetectomy as an Alternative to Lateral Release in Total Knee Arthroplasty (TKA)

This study presents the selective use of partial patellar lateral facetectomy for maltracking during primary TKA, as an alternative to lateral release. Twenty three partial facetectomies were performed out of 191 TKAs (12%). Balanced tracking was achieved in 22 knees. At follow-up 2 patients had persistent anterior knee pain. Mean Knee Society score (KSS) was 94 and mean functional KSS was 86. Mean patellar score was 28. Patellar tilt angles were within 2 degrees in all but one knee. Patellar translation was within 2 mm in all cases. No complications were recorded. A control group of 46 matched patients had similar functional and radiographic results. If tracking is not satisfactory at the conclusion of TKA, our method of choice would be partial lateral facetectomy.     

髌骨缩小联合外侧支持带松解对膝关节置换术的疗效影响

目的探讨髌骨缩小联合外侧支持带松解对人工全膝关节置换术后膝前痛发生及膝关节功能疗效的影响。 方法筛选2016年1月至2017年6月广东省第二中医院骨科136例退行性膝骨关节炎拟行初次单侧全膝关节置换术的患者136例(136膝)，剔除同侧髋病及严重内外翻畸形膝，术前按随机分配法分为观察组(术中行髌骨缩小联合外侧支持带松解，68例)和对照组(术中常规去除髌骨边缘硬化骨但不松解外侧支持带，68例)，余手术操作均一致。记录两组患者术前术后膝前痛及并发症发生情况、手术时间、美国特种外科医院(HSS)膝关节评分、髌骨Feller评分、膝前痛评分，并进行术前术后和两组间的比较。拍摄术后膝关节正侧位和Merchant位X(屈膝30°髌骨轴位片)线片，观察髌骨轨迹情况。对计数资料和正态分布的计量资料采用卡方检验或t检验。 结果观察组3例患者失访，2例外伤致胫腓骨骨折；对照组7例患者术中行"无拇指"试验发现需松解外侧支持带，排除研究；两组最终纳入63例和61例。所有患者均获得相同的随访时间。观察组术后膝前疼痛率为4.8%(3/63)，对照组为16.4%(10/61)，观察组优于对照组，差异有统计学意义(t＝6.325，P<0.05)；两组患者手术时间比较差异均无统计学意义(P>0.05)；术后18个月时两组患者HSS评分、Feller评分、膝前痛评分、膝关节活动度均较术前显著改善(P<0.05)；但观察组在HSS评分、髌骨Feller评分、膝前痛评分方面明显优于对照组(t＝3.125，P<0.05)；两组均未发生髌骨坏死、髌骨骨折、髌骨高压等并发症，比较差异无统计学意义(P>0.05)。观察组和对照组分别有2例和11例发生髌骨轨迹不良，比较差异有统计学意义(t＝11.218，P<0.05)。 结论膝关节置换术中进行髌骨缩小联合外侧支持带松解能明显减少膝前痛及并发症发生，有效改善膝关节功能并较好维持术后髌骨的轨迹，提高TKA手术的整体疗效。