Patella In Total Knee Replacement Research Articles

Resurfacing Versus Non-resurfacing Patella in Total Knee Replacement: When and What to Choose.

The opinion on the necessity of patella resurfacing has been deeply divided in the scientific community. There are three approaches to the management of the patella in total knee arthroplasty (TKA). The first method involves always resurfacing the patella, the second method involves never resurfacing it, and the third method involves resurfacing the patella only under specific circumstances. Different data support each of these strategies, but no consensus on the best management has been reached. This is a retrospective study of 106 cases of TKA (including 29 resurfaced patellas and 77 non-resurfaced patellas), over 5 years, at the Trauma-Orthopedics Department of theCheikh Khalifa International University Hospital, Mohammed VI University of Health Sciences, Casablanca, Morocco. Our objective is to conduct a comparative study between TKA with patella resurfacing and those without resurfacing, by analyzing the functional and radiological results obtained after the operation, to show each technique's advantages and disadvantages. The average age of our patients was 65 years with extremes ranging from 46 to 80 years. There was a clear female predominance with a sex ratio of 0.2. The left side was predominantly affected. Primary gonarthrosis was the main diagnosis. Our results showed no significant difference between the two groups in terms of patient satisfaction and Knee Society Score (KSS). Nevertheless, complications generated by resurfacing, such as infection, anterior pain, stiffness, and loosening of the patellar component, as well as additional costs and increased operative time, were observed. In the majority of meta-analyses, there was no discernible difference in clinical and functional results between the resurfaced and non-resurfaced groups, suggesting that patellar resurfacing is not beneficial and, therefore, unnecessary. It appears that regular resurfacing is not necessary. However, there is agreement that resurfacing the patella is the best course of action for patients with inflammatory arthropathy, considerable patella malalignment, and severe patellofemoral osteoarthritis. There are arguments in favor of each of the patella resurfacing techniques, but none of them are particularly compelling, each of these strategies has itsadvantages and should not be considered bad. The final decision, therefore, rests on each surgeon's practice, training, and experience.

The Effect of Surgeon Preference for Selective Patellar Resurfacing on Revision Risk in Total Knee Replacement: An Instrumental Variable Analysis of 136,116 Procedures from the Australian Orthopaedic Association National Joint Replacement Registry.

The optimum strategy regarding resurfacing the patella in total knee replacement (TKR) remains debated, with wide national and international variability. To minimize the confounders of a direct comparison of cases with or without resurfacing, we performed an instrumental variable analysis examining revision risk on the basis of surgeon preference for patellar resurfacing in TKR, specifically examining the subsequent patellar revision risk and all-cause revision risk among cases of surgeons preferring to perform resurfacing on a selective basis compared with those whose preference is to routinely resurface or who infrequently perform resurfacing. Data from the Australian Orthopaedic Association National Joint Replacement Registry from 1999 to 2016 were obtained to assess the cumulative percent revision, hazard ratio, and revision diagnoses for 3 cohorts, grouped according the surgeons' patellar-resurfacing preferences: infrequently (<10% of the time), selectively (10% to <90% of the time), or routinely (≥90% of the time). To avoid confounding from implant design or surgeon performance, only minimally stabilized TKRs using hybrid or cemented fixation and performed by surgeons performing ≥50 TKR procedures per year were included. A total of 136,116 procedures were included, with patients in all 3 cohorts having similar demographics. The selectively resurfaced cohort had a higher patellar revision risk compared with the routinely resurfaced cohort, with this risk being greatest in the first 4.5 years following the primary procedure, including 306% higher in the first 1.5 years, and remaining 50% higher after 4.5 years. In a subgroup analysis, increased revision risk was observed among males, females, those <65 years of age, and those ≥65 years of age. The infrequently resurfaced cohort had the highest risk of subsequent patellar revision, up to 482% higher, as seen in the first 1.5 years after the primary procedure, compared with the routinely resurfaced cohort. Additionally, the risk of all-cause revision was 20% higher for the selectively resurfaced cohort compared with routinely resurfaced. Surgeons who preferred selective resurfacing of the patella had a higher risk of patellar revision than those who had preference for routine resurfacing of the patella. Overall, a greater preference for resurfacing resulted in a lower risk of patellar revision. Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Patelloplasty without resurfacing of the patella in total knee replacement in patients without severe patellofemoral osteoarthritis

Purpose The aim of this prospective study was to assess the clinical results of nonresurfacing patelloplasty in total knee arthroplasty for osteoarthritis in middle-aged active patients with less erosion of the patellar articular cartilage, based on the hypothesis that patellar denervation provides pain relief and improvement in clinical results. Patients and methods The study was conducted during the period between June 2009 and December 2013 on 59 knees of 55 patients (four bilateral) who met the criteria. The procedure was performed in three hospitals using the same technique. We used the Knee Society Knee Scoring System for overall assessment of patients' knees. For patellofemoral status, we used the Outerbridge Grading System and we used the scale of Stern and Insall to assess anterior knee pain. Results The mean Knee Society Scores for the patients were improved from 15.2 preoperatively to 91.3 at postoperative follow-up. Fifty-one patients could use stairs without symptoms or with mild pain (grades 0 and I), and four patients were unable to use stairs due to severe symptoms (grade II); one of them was able to use stairs after 2 years of follow-up. Conclusion The results of patelloplasty without resurfacing of the patella in selected patients, clinically, radiologically, and intraoperatively are comparable to the results of patellar resurfacing, but with fewer hazards and complications.

(iv) The patella in total knee replacement

Abstract The role and management of the patella in total knee replacement remains controversial. The patella is an important sesamoid bone, with a rich vascular and neural network surrounding it, and it must be managed appropriately in order to ensure a satisfactory outcome after a total knee replacement. The controversies concern arguments for and against resurfacing as well as other considerations influencing the decision surrounding the management of the patella. There is sufficient evidence within the orthopaedic literature to support pretty much any reasonable decision that the surgeon might make. Ultimately, to resurface, not to resurface or to selectively resurface the patella is an operator-dependent decision, and in association with a good prosthetic design and surgical technique satisfactory and comparable results can be achieved.

Should we resurface the patella in total knee replacement?

Patellar resurfacing is a controversial issue in primary total knee replacement. So, we took advantage of a large study to try and answer this question. An open prospective multicentric study was conducted about the outcome of the Nex Gen Total Knee prosthesis with clinical and radiological follow-up at regular intervals (1, 2 and 5 years). The data were centrally collected and analyzed by independent observers. A total of whole 5,915 cases were included (487 in the French group); incidences of patello-femoral pain were observed in both French and international groups and compared between cases with or without resurfaced patellae. Only osteoarthritic cases were selected for this particular study. Statistical analysis was performed using a Pearson's Chi-square test with a 95% confidence interval. The frequency of preoperative pain was significantly higher in the French group; 85.1% versus 66.6% (p<0.05). No patello-femoral pain appeared in preoperatively painless patients in the French group. The frequency of lateral patellar release was similar in both groups. 35.7% of the patellae were resurfaced in the international group versus 98.8% in the French one. At 2 years, patello-femoral pain was observed in 6.3% of cases in the former group versus 0.7% in the latter one. The risk of having patello-femoral pain was 9.45 times higher in the international group. When considering resurfaced cases in both groups the risk of having anterior knee pain was not significantly different (p=0.35). In the French group, one case out of nine (11.1%) with patello-femoral pain had not been resurfaced, while 129 cases out of 151 (85.4%) had not had a resurfacing in the international group. This emphasizes the effect of patellar implant on pain. Although patello-femoral pain is multifactorial, this analysis tool is powerful in getting rid of the "center effect " (cf Swedish register). Even if a longer follow-up for confirmation is needed, our data favor patellar resurfacing with this type of implant in spite of the fact that the trochlear design was considered as anatomical.

The patella in total knee replacement: does it matter? 750 LCS total knee replacements without resurfacing of the patella.

Hingelike moving total knee replacement (TKR) has shown that the "rotating" function of the quadriceps muscle becomes lost. Dynamic work of the vastus medialis is no longer needed, and the static part of the quadriceps muscle assumes the major part of the work, beginning with continuously dislocating the patella to the lateral side. We operated on 436 knees using the LCS (De Puy Orthopaedics, Warsaw, IN) meniscal bearing TKR. No primary patellar resurfacing was necessary in this series. The New Jersey Score increased constantly over the 5-year follow-up from 83 after 2 years to 90 after 5 years. This shows that there is no deterioration which can be attributed to a deterioration in the patellar behavior. Nonresurfacing of the patella is a possible solution if the kinematics of the TKR allow physiological rotation, the prosthesis is built anatomically, the alignment is correct, the anatomy of decelerator/extensor mechanism is respected by the approach, and ligamentous stability is good.

Biomechanics of the patella in total knee replacement

An anatomical shape for the trochlea of the femoral component is an advantage in total knee design because in many cases the natural patella is preserved. The trochlea profile can be described as having a V-shape, with a wide angle and a circular base. In such cases the plastic patella should have the same profile, resulting in a generally conical shape. One of the questions regarding this design is whether the natural or artificial patella tilts in the femoral trochlea, producing wear and deformation of the plastic. We analysed the forces between the trochlea and the patella for various Q-angles and flexion angles. We found that the patella is fully stable and without tilting at all flexion angles, for a Q-angle of 14 degrees or less. Q-angles greater than this represent severe misalignment, and hence the cone-shaped patella is considered to be stable design.

The patella in total knee replacement: technical aspects on the femoral side.

The influence of femoral component positioning on patellar tracking is critical. The various possibilities of modifying the position of the femoral component relative to the distal femoral epiphysis are analyzed, and the ideal positioning in the medio-lateral, antero-posterior, and proximal-distal directions is described. Special emphasis is placed on the rotational positioning of the femoral component.

Shift and tilt of the bony patella in total knee replacement

Resurfacing the patella or not in total knee arthroplasty is generally still a quite controversial topic. In that context we felt a necessity to get more informations about the natural history of a non resurfaced patella in the prosthetic surrounding than only in comparison with a replaced patella. By the fact that we haven't been replacing patellae apart from special cases since up to five years, we have available a patient selection on which this question can be studied. Thirty primary total knee replacements with documented 2 year's follow up have been investigated by calculation of the radiological patellar shift and tilt relative to the natural groove on preoperative X-rays and to the prosthetic groove in the postoperative evolution. These results were matched with the range of motion obtained after two years and with persisting pain. Only mobile polyethylene inlays had been used. With regard to the patella no difference was found for one single complete tibial tray or two separately implanted unicompartimental tibial trays. As a rule an adaptation of the bony patellar contour to the prosthetic groove was observed with an increased density of the bony contact area with or without a fibrous interstitial layer. Based on their clinical follow up examination seven patients had to be adjointed to a "residual problem group", as they presented persisting pain (3) or a poor range of motion of 90/0/0 degree of flexion/extension or less. Only in this group we found cases with a postoperative shift over 5 mm (2) and a postoperative tilt over 15 degrees (3). Inside this group, also with a significant difference from the group without residual problems, there was furthermore a correlation between persisting pain and an important preoperative tilt and between a diminished range of motion and a considerable preoperative shift. It has to be pointed out that even the cases without long severe malposition before the arthroplasty but with unsatisfactory realignement referring to the patellar tilt (7 degrees-15 degrees) have been found pain free at the last follow up. One patient with a severe secondary increase of disalignment (16 mm/139 degrees) due to an aseptic tibial loosening represents a particular case. After corrective revision of the tibial implants this patient also got again a complete pain relief and a good range of motion without any surgical measure to the patella and inspite of an evident residual tilt. Thus we have to conclude that it is justified to take important pains with the realignment to obtain a residual patellar shift of less than 5 mm. Apart from usual operative steps during the implantation to favour a good patellar tracking, e.g. a high quadriceps release or a medially transposed refixation of the detached tibial tubercle can get necessary. On the other hand a residual tilt up to 15 degrees is well tolerated, as the unresurfaced patella presents an astonishing ability of adaptation to the prosthetic groove by remodelling of the bony contour and structure. Nevertheless in the included cases of severe preoperative malposition, in which we didn't replace the patella because of a good intraoperative bone quality, we had to put up with an increased incidence of late problems even with normalized patellar tracking. In such cases an extended indication to a patellar resurfacing may be considered.

Fracture of the Resurfaced Patella in Total Knee Replacement

Nontraumatic transverse stress fractures of the resurfaced patella occurred in 2 patients, one with a total condylar and the other with a GUEPAR arthroplasty. The blood supply of the patella is a critical factor in both pathogenesis and healing of stress fracture of the patella.