Total Patellar Skin Loss From Cryotherapy After Total Knee Arthroplasty

The use of cryotherapy after total knee arthroplasty is a very common therapeutic adjunct accepted as routine postoperative care. We present 2 cases of total patellar skin loss due to cryotherapy after total knee arthroplasty. Substantial soft tissue defects were created after the initial debridement of the necrotic tissue. Both patients were evaluated for frostbite, and the wounds were sharply debrided. Application of an advanced wound management technique involves the use of a collagen-glycosaminoglycan biodegradable bilayer matrix, silver impregnated antimicrobial dressing, and low-pressure vacuum device, followed by delayed split thickness skin grafting and low-pressure vacuum device. We find that this technique provided durable soft tissue coverage for necrotic wounds of the knee that do not involve the joint capsule.     

Patellar Denervation Reduces Postoperative Anterior Knee Pain After Patellar Resurfacing Total Knee Arthroplasty: A Randomized Controlled Trial

BackgroundThe benefit of patellar denervation (PD) in patellar resurfacing total knee arthroplasty (TKA) is still debatable. This prospective, randomized controlled trial investigated whether circumferential PD should be performed in patellar resurfacing TKA.MethodsA total of 241 patients who underwent unilateral TKA were randomized into PD or non-PD groups. Incidence, intensity, and presentation time of anterior knee pain (AKP) and clinical outcomes were evaluated at 3, 6, 9, 12, 18, and 24 months postoperatively.ResultsThe incidence of AKP was significantly lower in the PD group (6.4% vs 16.2%, P = .032). The intensity of AKP and patient satisfaction scores were significantly better in the PD group at 3 months but not after 3 months. The presentation time of AKP mostly occurs at 3 months after surgery. The Knee Society score, range of motion, Oxford score, patellar score, activity of daily living score, and visual analog scale of overall knee pain were not significantly different between the two groups during the follow-up period.ConclusionGiven that PD can improve AKP and patient satisfaction at an early period postoperatively without jeopardizing clinical outcomes at no additional cost, this inexpensive procedure readily available in nearly every operation room is strongly recommended during primary TKA with patellar resurfacing.     

Patellar Fracture After Total Knee Arthroplasty for Rheumatoid Arthritis

Patellar fracture is one of the most challenging complications of total knee arthroplasty, but relatively, little is known about it in patients with rheumatoid arthritis. We retrospectively analyzed 329 total knee arthroplasties performed in 230 female patients with rheumatoid arthritis to identify the incidence and risk factors for postoperative patellar fractures. The mean age was 61.8 years, and the mean follow-up period was 6.2 years. Patellar resurfacing was performed in all cases. Five postoperative patellar fractures (1.51%) were identified, and a thin residual patellar thickness and the use of posterior-stabilizing components were identified as significant risk factors, although the number of fractures was small in both groups. There was also tendency of higher age and greater joint line change observed in patients with fracture compared with those without fracture.     

Influence of Patellar Morphology Classified by Wiberg Classification on Knee Joint Function and Patellofemoral Tracking After Total Knee Arthroplasty Without Patellar Resurfacing

BackgroundTo evaluate the influence of patellar morphology on knee joint function and patellofemoral tracking in patients with primary osteoarthritis after total knee arthroplasty (TKA) without patellar resurfacing.MethodsWe performed a retrospective study of 156 patients with primary osteoarthritis who underwent TKA without patellar resurfacing from April 2018 to July 2019. As per Wiberg classification, patients were divided into Wiberg type I (group A, n = 38), II (group B, n = 88), and III (group C, n = 30) groups. The clinical data, postoperative follow-up data, and radiological data between three groups were compared.ResultsThere was no statistically significant difference in the HSS score and Feller score between the three groups before surgery and at each follow-up point after surgery (P > .05). At the last follow-up, there were no significant differences in the height and relative thickness of the patella between the three groups (P > .05). However, the incidence of anterior knee pain was significantly higher in group C than in the group B (P < .05). The patellar tilt angle was significantly larger in group C than in the groups A and B (both P < .05). The patellar facet angle was significantly larger in group A than in group B and C, which was also significantly larger in group B than in group C (both P < .05).ConclusionPatients with three different morphologic types of the patella both exhibited improved knee joint function after TKA, however, patients with Wiberg type Ⅲ patella were more prone to have poor patellofemoral tracking and anterior knee pain after surgery.     

Patellar Height After Total Knee Arthroplasty: Comparison of 3 Methods

Background

Total knee arthroplasty (TKA) is the gold standard procedure for knee osteoarthritis. However, there have been conflicting reports concerning whether TKA is associated with modifications in patellar height. This controversy might be partially explained by the diversity of methods used to measure patellar height. Therefore, we aimed at assessing the reproducibility of 3 radiological indices commonly used to evaluate patellar height—Insall-Salvati (IS), Blackburne-Peel (BP), and Caton-Deschamps (CD) ratios. Additionally, we aimed at evaluating the short-term differences between preoperative and postoperative patellar heights as measured by those 3 methods.

All-Polyethylene Tibial Component Use for Elderly,Low-Demand Total Knee Arthroplasty Patients

Background

Potential advantages combined with lower cost have prompted a renewed interest in modern all-polyethylene tibial designs.

Tibial Component Alignment After Total Knee Arthroplasty with Intramedullary Instrumentation: A Prospective Analysis

The best operative technique for achieving appropriate postoperative alignment following total knee arthroplasty (TKA) remains controversial, with proponents of extramedullary, intramedullary and computer-assisted techniques. One hundred ninety-two consecutive patients undergoing TKA were prospectively evaluated with full-length lower extremity radiographs. Patients underwent cemented TKA using femoral and tibial intramedullary instrumentation. Digital radiographs were analyzed using PACS (AGFA Healthcare, Ridgefield Park, NJ) software. Tibial component alignment was measured in the coronal and sagittal planes. Tibial component slope averaged 3.89° + 1.96 for the cruciate-retaining components and averaged 1.7° + 1.92 for PS components. The average coronal tibial component alignment was 90.00°, and 99% were within 3° of neutral mechanical alignment with only 2 (1%) outliers. Intramedullary instrumentation resulted in excellent postoperative tibial component and lower extremity alignment.     

Patellar Resurfacing in Total Knee Arthroplasty: A Cost-Effectiveness Analysis

Background

This study estimates the cost-effectiveness of patellar resurfacing in total knee arthroplasty (TKA).

Outcome After Isolated Polyethylene Tibial Insert Exchange in Revision Total Knee Arthroplasty

We identified 45 knees in 42 patients who had an isolated tibial insert exchange for a failed primary knee arthroplasty with a minimum of 2 years of follow-up. The mean age at revision was 68 years, and the mean time to revision was 80 months. Thirty patients completed follow-up questionnaires (Oxford Knee Score, University Of California Activity Index score, Western Ontario and McMaster Universities Osteoarthritis Index [WOMAC], and Short Form 12) with a mean follow-up of 58 months. Patients' current scores were compared with preoperative scores in 14 knees. Four patients (9%) were subsequently revised. Significant improvement was seen in the Oxford Knee Score, Short Form 12 physical component, and all WOMAC domains, but only 58% of patients had a clinically successful result by global WOMAC score. When patients are selected appropriately, an isolated liner exchange can significantly improve the function of the knee.     

髌骨置换与否对全膝关节置换效果的影响

目的评价髌骨置换与否对全膝关节表面置换的影响。方法对2000年1月至2001年6月间行膝关节表面置换的165例病人随机分为髌骨置换组和不置换组。置换组均采用同一种膝关节假体系统，由同组医生完成，术前和随访时评价HSS评分、髌骨评分和髌骨适合角、髌骨高度等影像学结果。所有评价均采用双盲的方式。结果在HSS评分和髌骨评分方面，两组无统计学差异。影像学评价两组无统计学差异。髌骨置换组的手术时间明显长于非置换组。结论对于骨关节炎病人，不置换和置换髌骨临床效果相当，影像学表现无明显区别。但置换组的手术时间更长。不论置换与否，手术时应注意对下肢力线的矫正。     

Lateral Patellar Facet Impingement After Primary Total Knee Arthroplasty: It Does Exist

The existence of the diagnosis “lateral patellar facet impingement” (LPFI) is controversial and the outcomes for surgical revision for symptomatic LPFI uncertain. We found that of the 3361 index knee revisions performed at our institution from 1995 to 2008, eleven were done for symptomatic LPFI. Their clinical histories and radiographic imaging were reviewed before and after revision TKA and were also compared to a group of control patients. We found no statistically significant differences between the groups in preoperative KS pain and function scores or radiographic features. However, the combined findings of pain in the subpatellar/lateral aspect of the knee post TKA and radiographic lateral facet contact were significantly associated with revision due to LPFI. Surgical revision results were variable, but ~ 2/3 of the patients were satisfied with the operation and had a significant improvement in KS function scores.     

Total Knee Arthroplasty After Intramedullary Tibial Nail: A Matched Cohort Study

BackgroundAs the use of intramedullary nails (IMNs) has become more common, there are an increasing number of patients requiring total knee arthroplasty (TKA) who have an indwelling tibial IMN. The purpose of this study is to compare implant survivorship, clinical outcomes, and complications in patients undergoing primary TKA with a history of tibial IMN to those without.MethodsWe retrospectively identified 24 TKAs performed between 2000 and 2017 after ipsilateral tibial IMN. Patients were matched 1:2 to patients undergoing primary TKA without history of tibial IMN based upon age, gender, body mass index, and year of surgery. Mean follow-up was 7 years.ResultsThe 10-year survivorship free of any revision was 100% for the tibial IMN cohort, and 96% for the control cohort, while the 10-year survivorship free of any reoperation was 91% and 89%, respectively (P = .72). Patients with a history of tibial IMN had similar Knee Society Scores to matched controls at 2 years (P = .77) and 5 years (P = .09). Acquired idiopathic stiffness trended toward being more common (17% vs 6%, P = .21) and operative time trended toward being longer (135 vs 118 min, P = .07) when the tibial IMN was removed, but there was no overall difference in complication rate between cohorts.ConclusionsTo our knowledge, this is the first report of primary TKA in patients with a history of ipsilateral tibial IMN. Compared to a matched cohort of patients without tibial IMN, these patients have similar outcomes in regards to implant survivorship, clinical outcomes, and risk of complications.Level of EvidenceTherapeutic Level III.     

Tibial Component Migration After Total Knee Arthroplasty With High-Viscosity Bone Cement

BackgroundHigh-viscosity (HV) bone cements have been formulated to offer potentially advantageous handling characteristics. However, alteration in the handling characteristics could influence implant fixation and survival. The primary objective of this study was to use radiostereometric analysis after total knee arthroplasty to assess the migration of the Triathlon tibial component fixed with HV cement (Simplex HV).MethodsTwenty-three patients were followed for two years with radiostereometric analysis examinations at 6 visits. Migration was compared with published thresholds and with a control group from a previously published study from the same center using the same implants fixed with a medium viscosity cement. Inducible displacement was assessed, and Oxford 12 Knee Scores and satisfaction were recorded.ResultsMean maximum total point motion migration reaching 0.40 mm (SD 0.16) at one year, and 0.41mm (SD 0.17) at two years, demonstrating a pattern of stable fixation, below published thresholds of acceptable migration, and not significantly different from the control group. One implant had continuous migration between 1 and 2 years but was clinically asymptomatic. Mean maximum total point motion inducible displacement measured at least one year postoperatively was 0.3 mm (SD 0.12). Mean Oxford 12 Knee Scores improved from 19 (SD 7) preoperatively to 42 (SD 8) 2 years postoperatively.ConclusionsThe use of HV cement demonstrated an acceptable pattern of migration at 2 years, indicating low risk for aseptic loosening.     

Arthroscopic Treatment of Patellar Clunk and Synovial Hyperplasia After Total Knee Arthroplasty

Patellofemoral pain, crepitus, and locking are infrequent symptoms after total knee arthroplasty (TKA). We performed a retrospective review of 25 patients who underwent arthroscopic debridement after primary TKA to treat the patellar clunk syndrome (15 knees) or patellofemoral synovial hyperplasia (10 knees). After surgery, patient-reported knee pain and crepitus as well as Knee Society knee and function scores improved in both groups. Postoperative knee range of motion remained unchanged. Arthroscopic debridement of symptomatic patellofemoral synovium after TKA is a safe and effective procedure.     

Anterior Knee Pain After Total Hip Arthroplasty in Developmental Dysplasia

Little has been reported on knee pain after total hip arthroplasty (THA). The purpose of this study was to investigate the incidence and mechanism of knee pain after THA. Two hundred fifty-two patients with hip dysplasia were clinically and radiographically assessed for knee pain before and after THA. Incidences of knee pain and patellofemoral alignment were analyzed with reference to postoperative change in leg length, femoral anteversion, and the femoral offset. Anterior knee pain was present in 16 patients (7.3%). Lateral patellar tilt was increased in all patients with knee pain and significantly larger compared to that seen in patients without knee pain. The increased patellar tilt disappeared within 3 months, but symptoms in 4 patients persisted for more than 3 months. The patellar tilt was significantly related to the amount of leg lengthening. This study demonstrates that THA influences the patellofemoral joint via leg lengthening and causes anterior knee pain.     

Uncemented Tibial Fixation Total Knee Arthroplasty

This is a prospective study of the midterm clinical and radiological outcome of 205 consecutive cases (185 patients) performed between January 2002 and December 2004 using a cementless fixed-bearing tibial tray. Complete clinical and radiological follow-up was done on 175 cases (157 patients). The average knee score at final follow-up using the Knee Society Score (Insall modification-1993) was 92 of 100 with 96.6% excellent compared with an average preoperative score of 57 of 100. Using radiological criteria, none of the patients had significant polyethylene wear or osteolysis; and the tibial trays had bone ingrowth in all but 1 case. Survivorship at an average of 5 years and 7 months was 98.85%. Based on our results, we conclude that an uncemented tibial component with Porocoat (DePuy, Warsaw, Ind) and hydroxyapatite coating provides sufficiently stable bone ingrowth fixation; and this tibial design has provided excellent and predictable midterm clinical and radiological outcome.     

Femoral Implant Design Modification Decreases the Incidence of Patellar Crepitus in Total Knee Arthroplasty

Background

Patellar crepitus is a complication most commonly seen in patients implanted with a posterior-stabilized total knee arthroplasty (TKA). Recently, design changes in the patellofemoral geometry and the intercondylar box ratio have been optimized in newer TKA designs. A comparative study was performed to analyze the incidence of patellar crepitus between a historical vs modern TKA design.

Computer-Assisted Total Knee Arthroplasty for Significant Tibial Deformities

Computer-assisted total knee arthroplasty has been demonstrated to provide reproducible limb mechanical alignment within 3° from the neutral mechanical axis. However, restoring proper implant and extremity alignment remains a significant challenge with proximal tibial deficiencies. In this prospective study, we describe the use of computer navigation to quantify the amount of bone loss on the medial or lateral tibial plateau and the use of these data to assess the need for augmentation with metallic tibial wedges. In this study, we demonstrate that computer-assisted total knee arthroplasty in patients with significant tibial deformities can accurately measure severe tibial deformities, predict tibial augment thickness, and provide excellent mechanical alignment and restore the joint line without excessive bony resection, repeated osteotomies, and repeated augment trialing.     

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.

Patellar Fracture After Total Knee Arthroplasty With Retention: A Retrospective Analysis of 2954 Consecutive Cases

BackgroundTo the best of our knowledge, there have been no large case studies on patellar fracture after total knee arthroplasty (TKA) with patella retention.MethodsFrom 2005 to 2019, 2954 consecutive TKAs with patella retention were retrospectively reviewed. The incidence of patellar fracture was confirmed. Perioperative demographic factors associated with patellar fracture were compared between the nonpatellar fracture control (randomly selected after age and sex matching) and patellar fracture patient groups. To confirm the prognosis of identified patellar fractures, Hospital for Special Surgery knee score, union rates, and complications after treatment were evaluated. Treatment outcomes were compared as per the treatment method, and fracture type was classified by shape.ResultsFor primary TKAs with patella retention, patellar fracture occurred in 32 of 2883 cases (incidence 1.11%). When comparing the preoperative demographic factors between the patellar fracture and control groups, there was a significant difference in knee flexion of the affected limb. Twenty-three cases were treated nonoperatively, and nine cases were treated operatively. Of the 32 patellar fractures, 28 had confirmed union, and the HSS score at the latest follow-up increased significantly from the preoperative score. The only complication noted after treatment was nonunion in three cases. We found no significant differences in treatment results as per the treatment method and fracture type.ConclusionPatellar fracture after TKA with retained patella is infrequent, with relatively improved clinicoradiological results over those of patellar fracture after TKA with resurfaced patella reported in the literature. The improved results did not differ as per the treatment method and fracture type.