Midterm results of cruciate retaining total knee arthroplasty in patellectomized patients

Background:

Total knee arthroplasty (TKA) in patellectomized patients gives inferior results when compared with those in which the patella is present. The literature is ambiguous about the role of cruciate retaining or sacrificing implants for these knees. In this study, we assessed the midterm results of TKA in patellectomized knees using a cruciate retaining implant.

Materials and Methods:

Thirty three patients with a prior patellectomy underwent a cruciate retaining TKA and were followed up for an average of 9.3 years (range 2-14 years). At each followup visit, they were evaluated clinically, radiologically and by the Hospital for Special Surgery Scoring System.

Results:

Twenty one knees did not have any pain or difficulty in climbing stairs, 10 knees were slightly painful on stairs but pain free on walking on flat ground and two knees experienced mild to moderate pain on walking up and down stairs as well as on flat ground. The average range of motion preoperatively was 87°, which postoperatively increased to 118°. The average Hospital for Special Surgery Knee scores increased from 52 to 89 points. None of the knees showed any progressive radiolucencies or evidence of any loosening/osteolysis or fractures in followup.

Conclusion:

Cruciate retaining TKA offers good results at midterm followup in patients with a prior patellectomy.     

Patellar resurfacing in total knee arthroplasty

Routine patella resurfacing in total knee arthroplasty has been debated for decades. The early total knee designs and surgical techniques lead to a high complication rate following patellar resurfacing. This lead to many surgeons abandoning this practice and either leaving the patella unresurfaced routinely or selectively resurfacing. Modern day randomized control trials and meta-analyses of these trials reveal a higher incidience of anterior knee pain and a resultant higher reoperation rate in nonresurfaced patellae. We argue that with modern day designs and surgical techniques, there is a low complication rate to resurfacing and little downside to resurfacing.     

Patellar clunk in total knee arthroplasty using modified Sigma posterior stabilized femoral component

Aim

The purpose of this study was to evaluate the efficacy of the enhanced PS femoral component design released in 2008 by DePuy. The patellar clunk syndrome has been reported in a significant number of patients following total knee arthroplasty. Design modifications of the implant have been made to reduce the incidence of the patellar clunk, especially in the posterior substituted designs.

Methods

130 total knee replacements performed using the enhanced PS femoral components were followed-up with clinical and radiographic evaluations.

Results

Patellar clunk was seen in 3 of the 130 knees (2%). This is much less than the incidence of patellar clunk reported until now.

Conclusions

Removal of the sharp ridge in the intercondylar groove in the newer implant seems to have been effective in reducing the incidence of the patellar clunk. It also indicates that the sharp ridge was the most probable cause of the clunk.     

The use of a revision femoral stem to manage a distal femoral periprosthetic fracture in a well-fixed total knee arthroplasty

Managing very distal femoral periprosthetic fracture above a total knee arthroplasty (TKA) is a difficult problem. When a cruciate sacrificing TKA is used, bone stock around the implant is compromised and, therefore, can limit fixation options. We present technique using the revision system femoral stem for the PFC Sigma TKA (Depuy; Leeds, England) to stabilize this particular type of fracture.     

Patellar resurfacing complications in total knee arthroplasty

Purpose

The ideal management of the patella during total knee arthroplasty (TKA) is still controversial. Patellar retention is generally associated with an increased rate of anterior knee pain; however, patient satisfaction is similar in cases of replacement or retention. When the patella is replaced, potential severe complications can occur. Aim of this study was to retrospectively review results of a continuous series of patients having been treated with TKA and patella resurfacing.

Methods

The charts of 1,600 consecutive total knee prostheses were analysed to evaluate the rate of patellar resurfacing. All implants were posterior stabilized; 310 patients having received a patellar replacement were reviewed at follow-up (FU) examination. Complete physical examination as well as administration of the Hospital for Special Surgery (HSS) score was performed. X-rays analysis included weightbearing anteroposterior (AP) and lateral views of the injured knee and bilateral skyline views at 30° flexion.

Results

Two hundred and eighty patients were available for clinical and imaging investigation at an average FU of 96 (58–144) months. Mean age at the time of surgery was 70 (62–80) years. Mean HSS score was 85.9 ± 7.6. The overall rate of patellofemoral complications was 7 % (19 cases); 13 patients claimed anterior knee pain, five had symptomatic patellar maltracking and one had patellar component loosening.

Conclusion

Our data are in accordance with those available in the literature. Recent meta-analyses demonstrated lower risk of re-operation after patellar resurfacing. However, when complications of the resurfaced patella occur, they can be potentially catastrophic events.     

Fracture of the femoral component in unicompartmental total knee arthroplasty

A fracture of the anterior flange of a femoral component in a unicompartmental knee has been seen. This was thought to be due to lack of bony support leading to cantilever bend. The solution would seem to be to add a metal web to strengthen that area of the femoral component.     

Effect of femoral component design on patellofemoral crepitance and patella clunk syndrome after posterior-stabilized total knee arthroplasty

The purpose of this study was to determine if recent changes to the femoral component of a particular posterior-stabilized total knee prosthesis would affect the incidence of postoperative patellofemoral crepitance and patella clunk syndrome. One hundred eight total knee arthroplasties were performed with the conventional design; 136 were performed after the femoral component was changed. Complications were compared between the groups with an average follow-up of 17.7 months and 12.4 months, respectively. Thirteen knees with the conventional design (12%) were found to have patellofemoral complications; no complications were noted with the new design (P < .0001). Femoral components with a deep trochlear groove and smooth transition of the intercondylar box appear to better accommodate any peripatellar fibrous nodule that may form after total knee arthroplasty.     

全膝关节置换术后髌骨的X线改变

[目的]探讨不置换髌骨的全膝关节置换术后髌骨的X线变化。[方法]对1999年～2004年间所进行的51例64个膝关节假体进行随访,常规不置换髌骨。平均年龄68.5岁(57～78岁),平均随访4.8年(2.5～8年)。在X线正侧位片和髌骨轴位片观察病人髌骨的退变、髌骨外移和倾斜程度的变化。[结果]手术后髌骨倾斜和外移均明显改善。随时间延长,大多数髌骨轨迹居中,没有明显退变。最常见的X线改变有髌骨上下极和外侧面增生,部分髌骨轨迹出现恶化。髌股关节的症状与髌骨的退变无明确相关。[结论]不置换髌骨的膝关节置换术后,髌骨的轨迹可得到明显改善,髌骨不会出现明显退变。     

The need for patellar resurfacing in total knee arthroplasty: a literature review

The controversy over whether or not to routinely resurface the patella during a total knee arthroplasty has persisted despite three decades of successful joint replacement procedures. Advocates for routine patellar resurfacing admit the occasional need for secondary patellar resurfacing and declare increased incidence of anterior knee pain in patients with non‐resurfaced patellae as a cause for worry. Surgeons that leave the patella unresurfaced cite avoidance of complications that include patellar fracture, avascular necrosis, patellar tendon injury and instability. This review discusses the available literature on patellar resurfacing through an evidence‐based analysis of randomized and pseudo‐randomized controlled trials and published meta‐analyses to date. The published literature seems to favour resurfacing the patellar routinely. Selective patellar resurfacing would be the ideal solution if sound pre‐operative criteria could be established. So far, a method for accurately predicting which patients can avoid patellar resurfacing has not been found. Future research looking at patellar resurfacing should concentrate on developing criteria for selecting those patients that would benefit from patellar resurfacing and those that would do as well without resurfacing, and thus, limiting potential surgical complications.     

全膝关节置换术中髌骨置换与否对膝前痛发生的影响

[目的]回顾性分析、比较全膝关节置换术中髌骨置换与否对膝前痛发生的影响,为临床治疗提供参考。[方法]对1994年10月~2004年10月行人工全膝关节置换术病人125例(148膝)按髌骨置换(84膝)和未置换(64膝)分为2组,并对其随访资料进行分析,膝关节评分采用HSS评分系统,髌骨评分采用Feller评分标准。结果使用SPSS统计软件进行统计学分析。[结果]置换组HSS评分由术前的(39.6±39.8)分进步为末次随访时的(90.9±8.2)分,髌骨评分由(14.4±6.4)分进步到(25.2±4.8)分,膝前痛分数也由(4.6±3.9)分进步为(10.6±4.1)分;未置换组HSS评分由术前的(38.8±9.8)分进步为(90.2±8.9)分,髌骨评分由(14.2±6.2)分进步到(25.1±4.8)分,膝前痛分数也由(4.8±3.8)分进步为(10.3±4.1)分。2组患者末次随访时膝前痛均较术前明显减轻,差异有显著性意义;置换组与未置换组比较,膝前痛减轻的差别无显著性意义。[结论]无论髌骨置换与否,患者的合理选择和正确的手术操作是避免术后膝前痛的关键所在。     

Rotating-hinge total knee arthroplasty in a patient with genu recurvatum after osteomyelitis of the distal femur

An 80-year-old man presented to our clinic with a chief complaint about pain and stiffness in the right knee. His history was significant for osteomyelitis of the right femur 64 years ago. Examination revealed a range of motion from 30 degrees hyperextension to 0 degrees extension. A rotating-hinge total knee arthroplasty was performed. Four years later, the patient ambulates painlessly with 1 cane. He has no extensor lag, and his range of motion is 0 degrees to 15 degrees.     

全膝关节置换术髌骨高度测量方法间差异研究

[目的]研究全膝关节置换手术前后髌骨高度4种测量方法的准确性和可重现性，这4种方法是Black—burne—Peel指数、Caton—Desehamps指数、InsaLL-Salvati指数和改良的Insall-Salvati指数。[方法]使用这4种方法对44例（45个膝）全膝关节置换的病人术前和术后侧位x线片进行2组独立的髌骨高度测量。2名实验者在特定的条件下以独立的方式分别进行了720个数据的测量。[结果]术前使用Insall-Salvati指数和改良的Insall—Salvati指数同使用Blackburne—Peel和Caton—Deschamps指数之间存在较大的差异。由于BlackbumePeel和Caton Deschamps指数以假体关节线为参照，术后观察者间差异明显减小。[结论]真实的髌骨高度测量和真实低位髌骨或高位髌骨的确认，需使用Insall—Salvati指数和改良的Insall-Salvati指数；Blackbume—Peel指数和Caton-Deschamps指数用来评估与关节面相关的髌骨高度和明确假性低位髌骨十分准确。     

Accelerometer-based computer navigation for performing the distal femoral resection in total knee arthroplasty

The use of intramedullary alignment guides for performing the distal femoral resection in total knee arthroplasty (TKA) have not been shown to be highly accurate. Forty-eight knees underwent a TKA using a portable, accelerometer-based surgical navigation system for performing the distal femoral resection (KneeAlign 2 system; OrthAlign, Inc, Aliso Viejo, Calif). Of the femoral components, 95.8% were placed within 90° ± 2° to the femoral mechanical axis in the coronal plane, and 93.8% of the TKAs had an overall lower extremity alignment within 3° of neutral to the mechanical axis, based on postoperative, standing, hip-to-ankle radiographs. The KneeAlign 2 is highly accurate in positioning the femoral component in TKA, and accelerometer-based navigation is able to reliably determine the hip center of rotation and femoral mechanical axis.     

Secondary patellar resurfacing in total knee arthroplasty: results of multivariate analysis in two case-matched groups

Although patellofemoral symptoms after patellar-retaining knee arthroplasty are common, no evidence has been published in the literature on the potential benefit from patellar resurfacing at a later stage. This study evaluates the effect of secondary (delayed) patellar resurfacing using comparisons between 2 case-matched groups of patients with primary and secondary patellar resurfacing. Furthermore, multivariate statistical methods were applied to study factors that may influence the final outcome. Our results suggest that although significant clinical improvement was seen after delayed patella resurfacing, the outcome of secondary patellar resurfacing is inferior to that expected for a similar group of patients with primary resurfacing. Furthermore, the timing (delay period) of the secondary resurfacing procedure appears to negatively affect the final outcome. This suggests that secondary patellar resurfacing, when indicated, should be considered at an early stage.     

Control‐matched computational evaluation of tendo‐femoral contact in patients with posterior‐stabilized total knee arthroplasty

Painful patellar crepitus is a potential complication in up to 14% of patients following posterior‐stabilized (PS) total knee arthroplasty (TKA). A recent clinical study identified influential patient and surgical variables by comparing a group of crepitus patients with controls matched for age, sex, and body mass index. The purpose of our study was to evaluate effects of variables identified as significant in the clinical study, including patellar ligament length, femoral component flexion, patellar button size, and position of the joint line, on contact between the quadriceps tendon and the PS femoral component. A previously verified finite element model was utilized to estimate tendo‐femoral contact during deep flexion activity. Using discrete perturbations, the computational model confirmed the clinical findings in that an increased patellar ligament length, flexed femoral component, lowered joint line, and larger patellar component all reduced potentially deleterious contact near the intercondylar notch. With the selected level of anatomic and component alignment perturbations, the most influential factor affecting tendo‐femoral contact was patellar ligament length. Three crepitus patients with matched controls were subsequently modeled, and contact with the anterior border of the notch was present in each crepitus patient, but none of the controls. Alternative surgical alignments for these patients were evaluated to improve the potential long‐term outcomes. By characterizing conditions that may lead to painful crepitus, the modeling approach supports clinicians by identifying pre‐surgical indicators and important alignment parameters to control intraoperatively. © 2012 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 30:1355–1361, 2012     

Total knee arthroplasty using the total condylar III knee prosthesis

Twenty-seven total knee arthroplasties (TKAs) were performed in 24 patients using the total condylar III knee prosthesis (TCP III) and were evaluated clinically and radiographically with a mean follow-up period of 4 years. Eighteen were revision TKAs, and nine were primary knee arthroplasties. Evaluations were made using the Hospital for Special Surgery (HSS) knee scale as well as the Knee Society radiographic evaluation method. Clinical results for all knees were 11% (3 of 27) excellent, 70% (19 of 27) good, 15% (4 of 27) fair, and 4% (1 of 27) poor. The one poor rating resulted from an intraoperative vascular injury. The results showed no statistical difference between revision and primary TKA. After operation, pain relief, range of motion, walking, function, and activity level improved in both the primary and revision patients. Radiolucencies 2 mm or greater in width were found in 6 of the 27 tibial components, in none of the 27 femoral components, and in 1 of the 19 patellar components. Only two tibial implants showed progressive radiolucencies. No correlation was found between the radiographic position of the implants and the clinical results. The authors conclude that the TCP III is a satisfactory choice for TKA in selected knees in which there is significant instability and in which intramedullary fixation is required.     

Patellar clunk syndrome after posterior stabilized total knee arthroplasty

Two hundred thirty-six posterior stabilized total knee arthroplasties (TKAs) were performed consecutively. Twenty-seven patellar clunk syndromes were identified in 25 patients. Insall-Salvati ratio, position of joint line, postoperative patellar height, and anterior-posterior position of tibial tray were measured. It was found that postoperative low-lying patella (P<.001) and anterior placement of tibial tray (P=.011) was associated with patellar clunk syndrome. Thirteen patients had bilateral TKAs of the same prosthesis (5 bilateral AMK knees and 8 bilateral Insall Burstein knees) but unilateral patellar clunk syndrome. The nonclunk sides were used as control for comparison with the clunk sides. The congruency and tilting of the patellar button in the skyline view were documented. It was observed that the congruency of the patellar button was less satisfactory in the clunk side (P=.019).     

Osteolysis of the distal femur after total knee arthroplasty

An 11.1% incidence of femoral osteolysis (30 cases in 28 patients) was identified in a series of 271 primary total knee arthroplasties. Two minimally constrained total knee designs (Synatomic [Depuy, Warsaw, IN] and Porous-Coated Anatomic [PCA, Howmedica, Rutherford, NJ]) were used in this patient population. Femoral osteolysis was observed in 26 Synatomic and 4 PCA knees. The average follow-up period was 52 months (range, 24–96 months). Osteolytic lesions were identified radiographically, adjacent to the nonporous-coated (smooth) regions of the anterior and posterior flanges of the Synatomic and PCA femoral components. The average time to the diagnosis of femoral osteolysis was 31 months (range, 7–96 months). The average patient age at the time of primary total knee arthroplasty was 63 years (range, 43–83 years) and the average weight was 180 lb. (range, 107–278 lb.). Sixteen of the 30 cases were in men. All of the cases with femoral osteolysis had cementless implantation. Tissue specimens were obtained from the 18 cases requiring revision. Implants remained in situ an average of 66 months (range, 15–96 months) prior to revision. In 16 of the 18 cases revised, the femoral component was clinically and radiographically stable. Six of 18 cases were revised for severe osteolysis. The remaining 12 cases were revised for failed metal-backed patellae, failed cementless tibial fixation, or advanced polyethylene wear. Wear of the thin tibial inserts and patellar components were the two sources of particulate polyethylene. Polyethylene debris was observed in all tissue specimens. In cases with failed metal-backed patellae or impingement of the tibial locking pin-and-clip, fine metallic debris was also noted in tissue specimens. Microscopic evaluation of the osteolytic tissue revealed a florid histiocytic response with occasional giant cells. Intracellular submicron particulate polyethylene was identified with polarized light microscopy and oil-red-O staining techniques. In the study population, statistically significant factors associated with femoral osteolysis included male gender (P < .05), younger age (P < .05), increased patient weight (P < .05), positive tibial osteolysis (P < .001), osteoarthritis (P < .07), and length of time in situ (P < .001). In addition, patients with a Synatomic prosthesis were at increased risk for osteolysis compared to patients with a PCA device (P < .02). The authors postulate that histiocytic granuloma gained access to the proximal femur primarily via the unbonded interface between the smooth metal and bone.     

Association of increased knee flexion and patella clunk syndrome after mini-subvastus total knee arthroplasty

This study reviewed 747 consecutive posterior stabilized total knee arthroplasty (TKA) to explain the increased incidence of patella clunk syndrome that occurred when the surgeon switched from a medial parapatellar arthrotomy to a mini-subvastus (MIS) TKA technique. The incidence of patella clunk syndrome increased with increased postoperative knee flexion. Six weeks after surgery, knees that developed patella clunk had a mean flexion of 124 degrees vs 117 degrees for knees that did not develop this syndrome (P = .016). As the MIS approach resulted in increased knee flexion, this approach was indirectly associated with the increased incidence of patella clunk. Knee flexion at 6 weeks postoperatively was 117 degrees for the MIS knees vs 108 degrees for traditional medial parapatellar arthrotomy knees (P < .001). The effect of increased knee flexion achieved with the MIS approach, which resulted in an increase in patella clunk, was mitigated by using a new posterior stabilized femoral component designed to minimize soft tissue entrapment.