The goals of any rehabilitation protocol should be to control pain, improve ambulation, maximise range-of-motion, develop muscle strength and provide emotional support.

Over 85% of TKR patients will recover knee function regardless of which rehabilitation protocol is adopted but the process can be facilitated by proper pain control, physical therapy and emotional support.

The remaining 15% of patients will have difficulty obtaining proper knee function secondary to significant pain, limited pre-operative motion and/or the development of arthrofibrosis. This subset will require a special, individualized rehabilitation program which may involve prolonged oral analgesia, continued physical therapy, more diagnostic studies and occasionally manipulation. Controlling pain is the mainstay of any treatment plan.

The program described herein has been used at Ranawat Orthopaedics over the last 10 years in more than 2000 TKRs.

Introduction

All current methods of cup placement use anterior pelvic plane (APP) as the reference. However, the majority of studies investigating the measurement of anteversion (AV) and abduction angles (AA) are inaccurate since the effect of pelvic tilt and obliquity are not considered. The aim of this study was to describe a reproducible, novel technique for functional cup positioning using internal and external bony landmarks and the transverse acetabular ligament (TAL).

Introduction

Ceramic femoral heads have proven to be more scratch resistant with better wettability and improved wear characteristics compared to metal heads in the laboratory setting. The objective of this study was to compare long-term survivorship and in vivo wear rates of ceramic and metal femoral heads against conventional polyethylene articulation in young patients.

Introduction

Studies have documented encouraging results with the use of fluted, tapered, modular, titanium stems in revision hip arthroplasty with bone loss. However, radiographic signs of osseointegration and patterns of reconstitution have not been previously categorized.

Introduction

It is not uncommon to encounter patients with atypical hip or lower extremity pain, ill-defined clinico-radiological features and concomitant hip and lumbar spine arthritis. It has been hypothesized that an anaesthetic hip arthrogram can help identify the source of pain in these cases. The purpose of this study is to analyze our experience with this technique in order to verify its accuracy.

Introduction: Computer-based wear analysis is currently the most accurate method for determining the in vivo wear rates of polyethylene liners during total hip arthroplasty. MRI of a total hip is emerging as the best method for determining the intra-articular volume of particulate debris. The purpose of this study is to determine if there is a correlation between polyethylene wear and the development of particle load in patients with highly crosslinked (HXLP) liners.

Materials and Methods: 20 well-functioning total hips (7 metal heads against HXLP liners and 13 ceramic heads against HXLP liners) in 18 young active individuals were analyzed using the following criteria: femoral head penetration of the liner was measured by Roman (ROntgen Monographic ANalysis) software and particulate load was calculated by MRI criteria as described by Potter et al. Clinical and radiographic analyses were performed using HSS, WOMAC, and criteria defined by DeLee, Charnley, and Engh. The average age of the patients was 57 (Range 45–67) and average follow-up was 1.6 y (range 1.0 – 3.0 y).

Results: All implants appeared well osteointegrated with no radiographic evidence of osteolysis. All patients had well-functioning total hips with a greater than one mile daily walking tolerance. A trend towards correlation was observed between increased polyethylene wear and increased particulate volumes. Average HXLP wear was 0.03 mm (range −0.19 to 0.27 mm) and average particle volume was 841 (range 6951 to 0). One patient in particular recorded 0.27 mm of polyethylene wear, mild particle disease and a particle disease volume of 3321 at 1.6 years follow-up. However, statistical significance could not be achieved with these data points.

Conclusions: There appears to be a relationship between polyethylene wear as measured by computer-based systems and particulate volume as measured by MRI. Limitations of the current methodology include the inability of computer-based systems to detect precise levels of minimal wear with HXLP liners, and the highly sensitive MRI images which may be detecting more than just wear debris.

The recent introduction of modern ceramic-on-ceramic total hip arthroplasties have demonstrated excellent clinical and radiographic results without catastrophic failure such as implant fracture associated with earlier designs. In laboratory wear testing, ceramicon-ceramic provides the least volumetric wear among all bearing surfaces. In recent years, with modern ceramic-on-ceramic bearing surfaces, clinical results with 5-to 7-year follow up have been good to excellent in 95–97% of cases. In spite of excellent results, certain limitations still exist including occasional fracture, stripe wear, squeaking, and neck-socket impingement producing metallic third body. Future improvement in ceramics (and other hard-bearing surfaces) and its coupling with other hard bearing surfaces appears to have significant advantages in reducing dislocation, impingement, stripe wear and squeaking.

The three distinct phases of design and development of total knee replacement (TKR) were:

1969–1985,

Hinge designs and early condylar designs highlight the first major period of TKR development from 1969 to 1985. These designs included but were not limited to the Waldius, Shiers, and GUEPAR hinges, Gunston’s Polycentric Knee in 1971, Freeman’s ICLH Knee in 1972, Coventry’s Geomedic Knee in 1972, St. George’s Sled Prosthesis in 1971, Marmor’s Modular Uni in 1971, Townley’s Condylar Design in 1972, Walker and Ranawat’s Duocondylar in 1971, Waugh’s UCI Knee in 1976, Eftekar’s Metal Backing in 1978, Murray and Shaw’s Metal Backed Variable Axis Knee in 1978, Insall and Burstein’s IB-1 Knee in 1978, the Kinematics in 1978, and finally Walker, Ranawat and Insall’s Total Condylar in 1978.

The Total Condylar Knee, developed by Walker, Ranawat, and Insall between 1974 and 1978, has been the benchmark for all designs through the 20th century. My personal experience of cemented TKR from 1974–2009 has shown a survivorship of 89%–98% at 15–20 years. Similar data has been presented in several 10+ year follow-up studies.

The next major phase of development gave birth to semi-constrained TKR, cruciate saving and substituting PS designs, improved instrumentation and improved cemented fixation. Other guiding principles involved improving alignment, managing soft-tissue balance for varus-valgus deformity, improving kinematics and producing superior polyethylene for reduced wear and oxidation. The advent of rotating platform mobile bearing knees with multiple sizes marked the most recent major advancement in TKR design.

With more total knee replacements being performed on younger, more active patients, improved design, better fixation (non-cemented), and more durable articulation are needed. The new standard for ROM will be 125 degrees. Non-cemented fixation, improved poly, such as E-poly, and the rotating platform design will play a major role in increasing the longevity of TKR to over 25 years.

The ability of optimised MRI to detect periarticular bony and soft tissue pathology in the post-arthroplasty hip is well documented; specifically it is able to detect early stages of particle disease well before osteolysis is apparent on radiographs. This is a prospective study designed to utilise MRI for the detection of early particle disease in asymptomatic patients after total hip arthroplasty.

Patients who underwent routine non-cemented THA were recruited from three different groups: metal-on-polyethylene, ceramic-on-ceramic, and ceramic-on-polyethylene bearing surfaces. All patients enrolled underwent optimised MRI one to three years (mean 1.7) after the index procedure. Images were analyzed for the presence of synovial proliferation, fibrous membrane formation or osteolysis. Particle disease was correlated with type of bearing surface, pain, activity level, patient satisfaction, and clinical outcome scales.

Thirty-two hips have been enrolled in the study to date. Early particle disease was seen in two of seven metal-on-polyethylene hips (29%), four of twelve ceramic-on-ceramic hips (33%), and six of thirteen ceramic-on-polyethylene hips (46%). Focal osteolysis was seen in one patient with a ceramic-on-polyethylene hip. These values were not statistically significant among the groups. The presence of early particle disease did not correlate with pain, activity level, patient satisfaction, or other clinical outcome scales.

This study allows patients with a well functioning total hip arthroplasty to be prospectively followed with MRI. It is the first to document the natural history of particle disease in vivo and considerably enhances our knowledge of periarticular pathology in the post-operative hip. These results demonstrate early particle disease is relatively common yet asymptomatic; they do not demonstrate advantages of any bearing couple over another for protection against particle disease at short-term follow-up.

We previously reported no clinical differences in short-term results in 26 patients that underwent fixed-bearing (FB) total knee arthroplasty in one knee followed by a rotating-platform (RP) version of the same implant in the contralateral knee at a later date. This study presents intermediate-term results in this unique cohort and uses optimised MRI for detection of particle disease in both knees.

Patients from the original series were asked to complete questionnaires regarding both knees. In addition, both knees were evaluated with optimised MRI, which has been shown to be useful in evaluating early particle disease and osteolysis before its appearance on radiographs.

Nine patients have been enrolled to date. At an average follow-up of 8.3 years for the FB side and 6.5 years for the RP side, no significant differences were found with respect to knee preference, pain, or overall satisfaction. Seven patients underwent MRI studies of both knees. Two FB knees demonstrated a massive intracapsular burden of particle disease (average 3066 mm3) with reactive synovitis, compared to no obvious particle disease in any RP knees. Osteolysis was seen around the femur in one FB knee and around the patella in two FB knees, compared to only around a single patella in the RP side.

RP knees continue to demonstrate excellent patient satisfaction that is comparable to clinical results of the FB design; however, FB knees demonstrate higher rates of particle disease and early osteolysis on MRI. This is the first study to demonstrate in vivo advantages of RP over FB designs. It is unclear whether this is due to the slightly longer follow-up period for the FB knees or a decreased wear rate in the RP design; these differences may become apparent with longitudinal follow-up.

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: The objectives of this study were to evaluate acetabular bone deficiency in revision THA with a simple classification on the anteroposterior pelvis radiograph and correlate the results of cementless hemispherical porous coated cup and cancellous bone graft reconstruction.

Methods: 70 acetabular revisions reconstructed employing large ‘jumbo’ porous coated cups with cancellous allo-grafting were evaluated at a mean follow-up of 5 years (range 2 – 10 years). During this time period 7 additional acetabular reconstructions required impaction grafting, cage reinforcement and cemented cups. Pre- and postoperative measurements of acetabular bone loss and the position of the revision component were performed with respect to a previously described triangle defining the placement and size of an idealcup. Impaction bone allo-grafting techniques were employed to fill defects. A minimum of 40% implant contact to host bone, especially in the weight-bearing dome region was attained in all cases and a minimum of 2 screws supplemented fixation to the ilium. Clinical evaluation comprised the HSS score and a patient assessment questionnaire (PAQ). Radiographically, cups were examined for filling of defects, ingrowth, graft consolidation, and stability.

Results: The mean HSS score improved from 18 to 33 out of a maximum of 40. The mean superior bone defect was 18 mm (range 10 – 25mm) and the mean medial bone defect was 7 mm (range 0 – 22mm). All the cement-less acetabular components were bone ingrown with the exception of one stable fibrous union. Allograft incorporation occurred at a mean of 7 months after surgery. Neither the status of Kohler’s line nor the Paprosky class correlated with eventual radiographic or clinical results.

Discussion: We present a simple method of evaluation of acetabular bone deficiency on the A-P pelvis radiograph employing a triangle that locates the ideal center of rotation of the hip. Superior bone loss upto 25 mm and medial migration as much as 22 mm has been successfully reconstructed employing impacted, cancellous allograft, large porous coated hemispherical Cementless acetabular components and screw fixation with excellent outcomes at intermediate-follow-up. Larger defects necessitate complex reinforced cage reconstruction.

Bankston et. al. reported that the clinical wear rates of molded acetabular cups was 50% less than a group of machined UHMWPE cups. However, due to covariables between groups including different femoral stems, cement technique, polyethylene resins and surgeons, unequivocal attribution of the low wear rates to direct molding could not be made.

In order to more directly assess the benefits of directly molded acetabular cups vs. machined cups, we report the comparison of hip simulation wear rates of machined and directly molded cups. These simulator results will then compared to two recent clinical reports on molded and machined cups of the same hip stem and cup design. The molded cups were made from 1900 resin and gamma sterilized in an inert atmosphere. The machined cups were made from HSS reference UHMWPE (4150) and gamma sterilized in air. The molded 1900 cups had a 55% lower wear rate after 5 million cycles on the hip simulator (14 v. 31mg/million cycles). Ranawat reported the average linear head penetration rate for 235 direct-lymolded, all polyethylene, cemented cups at a mean follow-up time of 6 years was .075mm/year. This is 56% lower than the rate of .17 mm/year he reported previously for the machined, uncemented metal-backed cups of the same design. These results provide further evidence that directly molding acetabular cups can provide wear rates over 50% less than machined cups both in both clinical and hip simulator evaluations. It is interesting to note based on other reports, that there is no osteolysis at 10 years of follow-up when the wear rates are < 1mm. The clinical and simulation wear rates reported here for the directly molded cups are within this performance range.

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.

Introduction: Mid-term follow-up has demonstrated good implant longevity for titanium fiber mesh and sintered bead designs, but few reports exist demonstrating the results of titanium plasma spray coated acetabular components in primary THR.

Methods: Between 1992 and 1995, a single surgeon performed 305 non-cemented primary THA’s in 260 patients. The selection criteria for non-cemented fixation were age younger than 65 and/or good bone quality. The hemispherical titanium plasma sprayed acetabular components were implanted with under reaming of 2 mm. Solid shells were used if a snug fit was attained with the trial. Screws were used to supplement fixation based on the surgeon’s judgment. The polyethylene liners were machined molded from ram extruded Hi-fax 1900H polyethylene resin gamma-sterilized in air or argon (inert) gas with elevated walls and locked into the shell via a Ring-Loc mechanism. These were mated with a 28mm cobalt-chrome femoral head and modular femoral component of metaphyseal-diaphyseal fit design with proximal titanium plasma spray porous coating. 15 patients have died, and 35 patients were lost to follow-up, leaving 225 hips in 210 patients that constitute the study cohort. The mean age was 55 years (range 24 – 60 years), and average.

Results: From this cohorts of patients, seven hips have been revised, two for infection, one for instability and four for osteolysis. The remaining patients had an average HSS score of 38 out of 40 at recent follow-up. Radiographically, the average cup inclination was 38.8 degrees. Eight hips had one zone interface lucencies, while three had two zone lucencies. There were no cases of continuous interface radiolucency or failure to achieve bone ingrowth. Nine hips demonstrated osteolysis, mostly in zones 2. The acetabular components in the cases with osteolysis were shells with unfilled screw holes in 3 and shells fixed with screws in 6. No osteolysis was detected in cases with solid hemispherical acetabular shells.

Discussion: Hemispherical titanium plasma sprayed ace-tabular components have achieved excellent durability at medium term follow-up, with a low incidence of fixation failure or osteolysis, and a low re-operation rate, even in a young, active group of patients. However, shells with screw holes appear to predispose to osteolytic lesions.

Cemented stem fixation is a proven technique in total hip arthroplasty (THA), however, aseptic loosening is a noted complication. Cementless fixation is also popular in THA, however thigh pain and osteolysis are known problems with short-term and long-term follow- up, respectively. In order to improve the initial development and durability of the osseointegration of porous coated cementless implants, hydroxyapatite (HA) has been claimed to provide a biological adjuvant for femoral stem fixation in THA.

There is no prospective, randomised long-term study comparing clinical radiographic findings between proximally HA-coated and non-HA coated surfaces of an identical stem design. We investigated 177 patients (199 hips) who received either HA-coated or non-HA coated stems. Clinical information from 163 patients (181 hips), including walking ability, thigh pain, sports activity, and overall patient satisfaction was collected. Evidence of radiolucencies, stem migration, and canal fill was measured on AP and lateral radiographs. In addition, tension trabeculae on the lateral aspect of the proximal stem and stress-induced remodelling of cancellous bone against porous surface (SIRCAP) were noted as signs of bone ingrowth.

Both groups of patients performed well on the basis of HSS scores, walking ability, sports activity, and overall patient satisfaction. However the non-HA group demonstrated a significant increase (p< 0.05) in activity- related thigh pain. There were no significant radiographic differences between patient cohorts with all stems demonstrating bone ingrowth. In our prospective, randomised study, we conclude that the use of HAcoated stems results in increased clinical satisfaction to the THA patient.

Leg length inequality, both actual and functional, is the most important cause of disappointment for the surgeon and his patient.

The reported incidence of leg length inequality of 1 cm has been reported to be between 23% and 50%, and half of these patients require a lift in their shoe. In the author’s opinion, there is a relationship between leg length and stability of the hip. Increase in leg length and offset improves soft tissue tension and reduces the dislocation rate.

The goal at surgery is:

To restore the center of rotation for the hip

The various tests for hip stability, soft tissue tension and contractures:

Assess component position

Leg length inequality is caused by:

Increase in anatomic leg length or offset or both