Introduction: Although the problems of patello-femoral kinematics in contemporary total knee arthroplasty are multifactorial, meticulous surgical technique is pivotal in providing optimal and durable function. The goal of this study was to evaluate the incidence of lateral release comparing fixed and mobile bearing posterior stabilized modular press-fit condylar TKA’s with patellar resurfacing.

Materials and methods: Cohort 1 comprised 100 consecutive cemented Press-Fit Condylar Sigma, (Johnson & Johnson, Raynham, Massachusetts) modular total knee prostheses with a posterior cruciate substituting design and dome shaped single peg patellar component implanted prospectively by a single surgeon. Cohort 2 comprised 100 consecutive cemented Press-Fit Rotating Platform Sigma (Johnson & Johnson, Raynham, Massachusetts) modular total knee prostheses with the same posterior cruciate substituting design and patellar component.

The surgical technique comprised cutting the tibial surface perpendicular to the long axis, ligament balancing in extension followed by femoral component rotation referenced off the proximal tibial cut to produce a rectangular flexion gap. The patella was cut to the level of the lateral facet and tibial component rotation was referenced off the center of the ankle. Lateral release was performed if congruent patello-femoral contact was not attained in knee flexion. Clinical and radiographic review was performed as per Knee Society criteria. Additional radiographic evaluation included patellar displacement, tilt, residual bone thickness and coverage ratio. A patient-administered questionnaire was used to evaluate anterior knee pain and patello-femoral function 1 year after surgery.

Results: The incidence of lateral release in the fixed-bearing cohort was 10% 1 compared to 0% in the mobile bearing cohort (p< 0.05). There were no significant differences in terms of clinical or radiographic parameters at short term.

Discussion: This study demonstrates the benefit of self-correction of tibiofemoral rotational mismatch with mobile bearing TKA’s and improvement in patello-femoral tracking. Longer follow-up is necessary to confirm the effect on patello-femoral wear, fixation and durability.

Introduction: This prospective review provides an update on a cohort of 150 consecutive primary TKA’s with intermediate follow-up (mean 10 years) and provides insight into the benefits of the device and casts light on the effects of polyethylene wear in posterior stabilized modular designs.

Materials: Between February 1988 and February 1990, 150 consecutive cemented Press-Fit Condylar (PFC, Johnson & Johnson, Raynham, Massachusetts) modular total knee prostheses (118 patients) with a posterior cruciate substituting design were implanted prospectively by a single surgeon. Two independent observers employing a patient administered questionnaire and clinical and functional Knee Society scores assessed the clinical outcome. Radiographic review was performed per the Knee Society criteria. The cumulative survivorship analysis was performed in terms of best case and worst case.

Results: 20 patients (30 TKR) died and 14 patients (15 TKR −10%) were lost to follow-up. The mean duration of follow-up in this cohort of survivors was 10 years (range 8.5 – 12 years). The mean clinical and functional scores were 88 and 73 points respectively. Of the 105 TKR followed up, good to excellent results have been attained in 89.5%. 45 patients reported participation in recreational sports. The overall projected clinical and radiographic survival was 93.6% at 12 years (CI +5.9%). Revision TKA was performed in 5 knees – 2 infection, 1 instability and 2 polyethylene wear, synovitis and osteolysis. There were no cases of aseptic loosening in the absence of polyethylene wear.

Discussion: Although the 12-year survivorship results of the cemented, posterior cruciate substituting press-fit condylar modular total knee prosthesis have been successful in terms of quality of fixation, the phenomenon of ‘back-side’ polyethylene wear at the modular tibial base-plate and resultant osteolysis offset the benefits of the modularity with longer follow-up. Attention needs to be focused on the improvement of the locking mechanism or alternatives with improved newer wear-resistant polyethylene, one-piece tibial components or newer implant designs with mobile bearings such as rotating platforms with posterior substituting design.

Introduction: Polyethylene wear debris is the main contributing factor that leads to aseptic loosening and osteolysis. The main objective of this study was to evaluate the role of hydroxyapatite (HA) in third-body polyethylene wear in total hip arthroplasty.

Materials: 199 primary cementless THA’s (174 patients) performed by a single surgeon were enrolled in a prospective randomized study comprising hydroxyapatite and non-hydroxyapatite coated femoral implants. The femoral component had metaphyseal-diaphyseal fit design with proximal plasma sprayed titanium circumferential porous coating. The hydroxyapatite coating was 50 – 75 micrometers over the porous surface with the components of identical design. The acetabular component was plasma sprayed titanium porous coated shell without hydroxyapatite. T he polyethylene liners were machined molded from ram extruded Hi-fax 1900H polyethylene resin gamma-sterilized in argon (inert) gas. Clinical and Radiographic evaluation was performed employing HSS scores and Engh criteria.

Results: At a mean follow-up of 5 years, the radiographs of 83 HA and 73 Non-HA hips were evaluated by two independent observers utilizing computer-assisted wear analysis on digitized standardized radiographs described by Martell et al (1997). The radiographs were also evaluated for osteolysis or aseptic loosening.

The mean linear wear rate in HA group was 0.19mm/yr and in the non-HA group was 0.21mm/yr, which was not significant (p> 0.05). There was no case of osteolysis or aseptic loosening of any component. Both groups had comparable outcomes in terms of HSS scores, walking ability and sports participation.

Discussion: This study has attempted to demonstrate through an appropriately controlled in vivo study that hydroxyapatite does not play a significant role in third-body polyethylene wear in THA at a mean follow-up of five years. The concern of three-body wear with hydroxyapatite coating is no greater than porous coated cementless implants.

Introduction: Polyethylene wear debris is the main contributing factor that leads to aseptic loosening and osteolysis. The main objective of this study was to evaluate the role of hydroxyapatite (HA) in third-body polyethylene wear in total hip arthroplasty.

Materials: 199 primary cementless THA’s (174 patients) performed by a single surgeon were enrolled in a prospective randomized study comprising Hydroxyapatite and non-hydroxyapatite coated femoral implants. The femoral component had metaphyseal-diaphyseal fit design with proximal plasma sprayed titanium circumferential porous coating. The hydroxyapatite coating was 50 – 75 micrometers over the porous surface with the components of identical design. The acetabular component was plasma sprayed titanium porous coated shell without hydroxyapatite

Introduction: This purpose of this prospective review is to evaluate the 12-year results of a previously unreported collarless, cemented, normalized, straight-backed Omnifit femoral stem with a surface roughness of 30–40 microinches.

Methods: Between January 1986 and June 1991, a single surgeon prospectively implanted 305 consecutive cemented THA’s (275 patients) utilizing second-generation cement technique and a posterolateral exposure. The acetabular component was cemented all-polyethylene (4150 resin), with calcium stearate and gamma sterilized in air. Two independent observers employing a patient administered questionnaire, HSS scores and established radiographic criteria performed clinical and radiographic evaluation. The cumulative survivorship analysis was analyzed in terms of best case and worst case.

Results: The demographics included a mean age of 70 years with 170 females and 105 males and a mean body weight of 154 lbs. The preoperative diagnosis was osteoarthrosis in 260 hips, rheumatoid arthritis in 20, fracture in 13, AVN in 8, Paget’s in 2 and hip dysplasia in 2. The mean HSS score was 37.5 out of 40 at last follow-up. The mean clinical follow-up was 12 years and mean radiographic follow-up was 10 years. The overall projected clinical survival was 95.1% at 15 years (CI +3.4%). The cement mantle was grades A or B in 90% and grade C1 in 10%. Femoral stem alignment was neutral in 53%, valgus in 31% and varus in 16%. Revision THA was performed in 9 hips. Both components were revised in 3 cases (2 infection, 1 recurrent dislocation). Socket revision was performed in 4 cases (1.31%) and femoral component revision in 2 cases (0.65%) due to aseptic loosening.

Discussion: This report demonstrates the excellent results of the collarless, cemented, normalized femoral stem with a surface roughness of 30–40 microinches. Although controversy exists on surface roughness and porosity reduction, meticulous technique in the attainment of a centralized femoral stem with a good cement mantle, provides a reproducible, high quality of function and durability of THA in patients 60 – 80 years of age at 12-year follow-up.