The natural history and significance of radiolucent lines at a cemented femoral interface

Mid-term clinical radiological results of the constrained condylar knee prosthesis in total knee revision

INTRODUCTION

The aim of the present study is to analyze the clinical-radiological outcomes of patients undergoing knee prosthesis revision surgery using constrained condylar prosthesis (LCCK; Zimmer-Biomet).

MATERIAL AND METHODS

Retrospective study of 89 patients operated on between the years 2008 and 2020 with a minimum of 2 years of follow-up. Clinical outcomes were evaluated using the WOMAC Index score and KOOS scales. Radiological results (radiolucent lines, osteolysis, and cortical hypertrophy) were evaluated by two independent observers. Implant survival was analyzed using the Kaplan-Meier method.

RESULTS

At the end of follow-up, a mean WOMAC Index score of 78.67 and KOOS score of 68.8 were obtained. Radiolucent lines (both non-progressive and progressive) were detected in 83.3% of the patients in the sample. Areas of osteolysis > 5 mm around the components were present in 6.75%. Cortical hypertrophy was seen around the femoral stem in 20.3% of cases, around the tibial stem in 20.3% and around both components in 6.76%. No statistically significant relationship was found between the presence of radiolucent lines, osteolysis or cortical hypertrophy with functional results. Implant survival was 88.1% at 13 years.

CONCLUSION

The present study shows high survival of LCCK prosthesis in revision surgery. The progressive radiolucencies, were associated with worst clinical outcome.

Clinical long-term results of radial head arthroplasty in comminuted radial head fractures

Modern radial head prostheses have recently become more common in the treatment of comminuted radial head fractures. The goal of this study was to evaluate how well the EVOLVE^® modular metallic radial head implant prosthetic restores the functional range of motion and stability of the elbow. 30 patients with comminuted radial head fractures received an arthroplasty with an EVOLVE^® prosthesis in our institution. 20 of those patients were available for long-term follow-up (mean > 10 years). The outcomes were assessed on the basis of pain, motion, and strength. The overall outcome was scored with functional rating scores. According to the Broberg-Morrey elbow evaluation score, after a mean follow-up period of 10.2 years, ten (50.0%) patients were rated as very good, four (20.0%) as good, six (30.0%) as satisfactory, and none as poor. In the long-term results the Broberg-Morrey score increased from 79 (in short-term results) to 89 points. The Disabilities of the Arm, Shoulder, and Hand (DASH) outcome measure questionnaire showed an average of 16.2 points. Initially, patients had an extension deficit of 20°, which was reduced to 5° at the latest follow-up. In our long-term results, an improvement in the function of the elbow was observed after arthroplasty using a metallic modular radial head implant. Comminuted radial head fractures with elbow instability can be treated effectively with the EVOLVE^® radial head prosthesis, which restores stability in acute treatment. Our long-term results after 10.2 years demonstrate good functional outcome and low major complication rate. IV.

Functional outcomes & metal ion levels following ceramic on metal total hip arthroplasty: 9 Year follow-up

In this study, we evaluate the mid-term functional and radiological outcomes of Ceramic on Metal Total Hip Arthroplasty (CoM THA) THA. 66 CoM THAs were performed between 2008 and 2010. These were evaluated and followed up in 2017-18, at a mean follow-up of 9 years to record the Oxford Hip Score [OHS] and whole blood Cobalt and Chrome levels. Our all cause revision rate was 4.5% (3 out of 66). At mid-term follow up, patients with CoM THAs are mostly asymptomatic with reasonable functional outcomes, we have reported similar revision rates in conjunction with raised blood metal ion levels and frequency of radiolucent lines.

Total hip arthroplasty after lower extremity amputation

There are approximately 1.6 million lower extremity amputees in the United States. Lower extremity amputees are subject to increased physical demands proportional to their level of amputation. Lower extremity amputees have a 6-fold higher risk of developing radiographic osteoarthritis in the ipsilateral hip and a 2-fold risk of developing radiographic osteoarthritis in contralateral hip when compared with the non-amputee population. Additionally, there is a 3-fold increased risk of developing radiographic osteoarthritis in the ipsilateral hip after an above knee amputation when compared with a below knee amputation. The authors retrospectively reviewed 35 total hip arthroplasties after lower extremity amputation. The mean clinical follow-up was 5.3±4.0 years. The mean time from lower extremity amputation to total hip arthroplasty was 12.2±12.8 years after a contralateral amputation and 5.4±6.0 years after an ipsilateral amputation (P=.050). The mean time to total hip arthroplasty was 15.6±15.4 years after an above knee amputation and 6.4±6.1 years after a below knee amputation (P=.021). There was a statistically significant improvement in the mean Harris Hip Score from 35.9±21.8 to 76.8±12.8 with total hip arthroplasty after a contralateral amputation (P<.001). There also was a statistically significant improvement in the mean Harris Hip Score from 25.4±21.7 to 78.6±17.1 with total hip arthroplasty after an ispilateral amputation (P<.001). Three (17.7%) total hip arthroplasties after a contralateral amputation and 2 (11.1%) total hip arthroplasties after an ipsilateral amputation required revision total hip arthroplasty. Patients with an ipsilateral amputation or a below knee amputation progress to total hip arthroplasty faster than those with a contralateral amputation or an above knee amputation, respectively. Lower extremity amputees experience clinically significant improvements with total hip arthroplasty after lower extremity amputation.

Do capsular pressure and implant motion interact to cause high pressure in the periprosthetic bone in total hip replacement?

When there is a debonding at the bone-implant interface, the difference in stiffness between the implant and the bone can result in micromotion, allowing existing gaps to open further or new gaps to be created during physiological loading. It has been suggested that periprosthetic fluid flow and high pressure may play an important role in osteolysis development in the proximity of these gaps. To explain this phenomenon, the concepts of "effective joint space" and "pumping stem" have been cited in many studies. However, there is no clear understanding of the factors causing, or contributing to, these mechanisms. It is likely that capsular pressure, gap dimensions, and micromotion of the gap during cyclic loading of an implant can play a defining role in inducing periprosthetic flow. In order to obtain a better understanding of the main influences on periprosthetic flows and the development of osteolysis, steady state and transient 2D computational fluid dynamic simulations were performed for the joint capsule of the lateral side of a stem-femur system, and a gap in communication with the capsule and the surrounding bone. It was shown that high capsular pressure may be the main driving force for high fluid pressure and flow in the bone surrounding the gap, while micromotion of only very long and narrow gaps can cause significant pressure and flow in the bone. At low capsular pressure, micromotion induced large flows in the gap region; however, the flow in the bone tissue was almost unaffected. The results also revealed the existence of high velocity spikes in the bone region at the bottom of the gap. These velocity spikes can exert excessive fluid shear stress on the bone cells and disturb the local biological balance of the surrounding interstitial fluid which can result in osteolysis development. High capsular pressure was observed to be the main cause of these velocity spikes whereas, at low capsular pressure, gap micromotion of only very long and narrow gaps generated significant velocity spikes in the bone at the bottom of the gaps.

Femoral fixation pattern in cemented Oxford unicompartmental knee arthroplasty--an experimental cadaver study

Femoral component loosening is a rare but serious complication in cemented Oxford unicompartmental knee arthroplasty (OUKA). In a cadaver study, OUKA was performed in 24 knees to evaluate the femoral fixation pattern. Due to the geometry of bone and implant, three different zones were identified. Complete cement mantles and good interdigitation were found in the spherical part of the implant (zone 1) and around the peg (zone 3), which implies that these are most important for implant fixation. The posterior plane facet (zone 2) is the weak point of the interface due to incompleteness of the cement mantle and a lack of interdigitation. This study suggests that the cancellous bone in zone 2 and the drill holes in sclerotic bone areas should be filled with cement and pressurised prior to component seating.

Total hip arthroplasty revision in elderly people with cement and Burch-Schneider anti-protrusio cage

Total hip arthroplasty revision is increasingly becoming a common procedure, but the acetabular bone loss and the advanced age of the patients make revision procedures extremely complex and technically demanding. The aim of the present work is to examine the clinical and radiological results of the Burch-Schneider anti-protrusio cage (APC) implanted in revision hip arthroplasty with severe acetabular bone deficiency in elderly people. Between February 1994 and November 2005, a total of 60 revision operations of acetabular components were performed in 60 select patients (42 females and 18 males), using the Burch-Schneider APC. The indication for the Burch-Schneider APC use was massive pelvic bone loss with migration of the prosthesis cup and high-grade acetabular defects (type III or IV AAOS). The mean age at the time of surgery was 82 years (range 78-85 years). Polymethylmetacrylate cement (PMMA) was used to fill bony deficiencies in all the procedures. No graft was used. The average Harris Hip Score had improved from 28.2 preoperatively to 82.5 points at the time of follow-up. According to the classification of Gill et al., we have seen no Burch-Schneider cages definitely loose or probably. Only one acetabular component has been revised (for recurrent dislocation). Acetabular reconstruction with the use of cement and an acetabular support ring appears to have a useful role in the treatment of severe acetabular bony deficiency in elderly patients and may provide a definitive reconstruction.

Pulsed lavage reduces the incidence of radiolucent lines under the tibial tray of Oxford unicompartmental knee arthroplasty: pulsed lavage versus syringe lavage

The aim of the study was to determine whether the incidence of radiolucencies can be reduced using pulsed lavage before cementing the tibia in unicompartmental knee arthroplasty (UKA). We prospectively studied a consecutive series of 112 cemented Oxford UKA in 100 patients in two centres. In group A (n = 56) pulsed lavage and in group B (n = 56) conventional syringe lavage was used to clean the cancellous bone. The same standardised cementing technique was applied in all cases. At a minimum follow-up of one year patients were evaluated clinically and screened radiographs were obtained. The cement bone interface under the tibial plateau was divided into four zones and evaluated for the presence of radiolucent lines. All radiographs were evaluated (n = 112), and radiolucencies in all four zones were found in two cases in group A (4%) and in 12 cases in group B (22%) (p = 0.0149). Cement penetration showed a median of 2.6 mm (group A) and 1.5 mm (group B) (p < 0.0001). We recommend the routine use of pulsed lavage in Oxford UKA to reduce the incidence of radiolucency and to improve long-term fixation.

The assessment of intraoperative prosthetic knee range of motion using two methods

The commonly used standard goniometer has been shown to underestimate knee flexion. Computer-assisted navigation for total knee arthroplasty offers itself as an alternative method to quantify knee flexion. The goal of our study was to determine the reliability of each instrument in measuring intraoperative range of motion during total knee arthroplasty. We prospectively performed intraoperative measurements using both methods on 99 knees. We assessed the variability between the 2 devices and the confounding effect of body mass index. The mean difference between the goniometric and navigation measurements was significant for flexion, extension, and range of motion. Increasing body mass index accentuated this difference. The goniometric method underestimated flexion measurements as compared to navigation, especially in patients with high body mass index. Our study confirms that navigation is a reliable tool for performing in vivo assessment of range of motion.

Assessment of radiolucent lines in cemented shoulder hemi-arthroplasties: study of concordance and reproducibility

We report on the concordance and reproducibility of the evaluation of radiolucent lines in the humeral component of shoulder arthroplasty. Thirty-two shoulder prostheses were assessed independently, on two occasions, by five observers. The level of inter- and intra-observer agreement was calculated using the kappa statistic. Intra-observer agreement: the overall kappa values ranged from 0 to 0.6, meaning poor, fair and moderate agreement levels. Inter-observer agreement: when the anteroposterior (AP) views were analysed, the values obtained for the bone-cement interface ranged from 0.290 to 0.539, meaning a poor-to-moderate agreement. For the cement-implant interface, the values ranged from 0.064 to 0.684, meaning a poor-to-good agreement. When radiolucent lines of the humeral component were analysed, inter-observer agreement proved to be as low as that obtained when total hip or knee components were analysed. Intra-observer agreement showed better results.

[The cemented MS-30 stem. A multi-surgeon series of 333 consecutive cases]

INTRODUCTION

So far there is only one peer-reviewed long-term publication from the inventors' clinic for the MS-30 stem.

MATERIAL AND METHODS

In a retrospective study we followed the first 333 consecutive MS-30 stems. All patients with 5- to 11-year follow-up were clinically and radiographically evaluated. At the time of implantation the criteria of modern cementing techniques were not implemented. Clinical evaluation was done using the scores of Harris and Merle d'Aubigné and Postel. Radiographic evaluation included quality of the cement mantle (true lateral radiographs taken under fluoroscopy), stem subsidence, loosening signs, and the risk for pending failure.

RESULTS

At follow-up 12 hips had undergone femoral revision: 3 for aseptic loosening, 6 for infection, 1 for periprosthetic fracture, and 2 for recurrent dislocation. The overall survival for all reasons at 10 years was 96.1%; survival with aseptic loosening as an end point was 99.0%. The median Harris Hip Score at follow-up was 80 (26-100) points. Radiological evaluation revealed a thin cement mantle (<2 mm) in approximately 2/3, predominantly on the lateral views (Gruen zones 8/9). One-third of all reviewed prostheses were considered at risk for pending failure, which strongly correlated with the initial quality of the cement mantle.

CONCLUSION

Midterm results with the MS-30 stem are encouraging and an even better long-term outcome can be expected with a better cement technique.

Prediction of Charnley femoral stem aseptic loosening by early post-operative radiological features

We describe the association between immediate post-operative radiological appearances and early aseptic failure of total hip replacement. Sixty-three hips were entered into the aseptic failure group and 138 into the control group. Alignment of the femoral stem was not associated with failure (p=0.283). Thickness of the cement mantle was associated with failure in Gruen zones 6 (p=0.040) and 7 (p=0.003). A significant association for the presence of radiolucent lines was found for Gruen zones 3 (p=0.0001) and 5 (p=0.0001). Grade of cementation was associated with failure for Barrack grades C (p=0.001) and D (p=0.001). This study has demonstrated that easily applied radiological criteria can be used to identify 'hip arthroplasties at risk' from the immediate post-operative radiograph.

Progression of radiolucent lines in cementless twin-bearing low-contact-stress knee prostheses: a retrospective study

A total of 134 low-contact-stress (LCS) total knee arthroplasties (TKAs) with mobile meniscal bearings were implanted in 121 patients with a mean age of 74 years (range, 49-91 years) at the time of surgery. The radiographic results obtained from 91 prostheses at an average follow-up of 7.5 years (range, 4.8-9.6 years) showed that radiolucent lines (RLL) appeared most frequently near the tibial plateau (97%) and that most RLL were present immediately postoperatively (67%) or appeared within the first year (96%). RLL were predominantly nonprogressive (99%). Progressive RLL did not affect the fixation or stability of the prosthesis. There were no revisions for aseptic loosening. Cementless LCS TKA achieves excellent radiologic and clinical midterm results.

Small stem Exeter total hip replacement: clinical and radiological follow-up over a minimum of 2.5 years

PURPOSE

To evaluate the clinical and radiological outcome in patients undergoing small stem Exeter total hip replacement.

METHODS

A total of 46 small stem Exeter total hip replacements were performed on 44 consecutive patients (18 men and 26 women) attending the University of Malaya Medical Centre. The mean age at the time of operation was 58 years (range, 24-81 years). Of the 46 procedures performed, 35 were primary total hip replacements and 11 were revision operations, with aseptic loosening of the original implant being the main indication for revision. The main indications for surgery in primary cases were avascular necrosis and rheumatoid arthritis. Clinical and radiographic outcomes were assessed at 6 weeks', 12 weeks', 6 months' follow-up, and annually thereafter. Postoperative cementing technique was also assessed.

RESULTS

The mean follow-up period was 4 years. The mean Oxford Hip Score improved from 46 points preoperatively to 17 points at the final follow-up examination. There were no revision operations, no implant breakages, and no excessive migration of the implants. The potential complications of implant failure due to smaller implant size and increased patient activity were not observed.

CONCLUSION

Due to the smaller size of Asian femora, the small stem Exeter implant is a very useful development. This study suggests that it will perform as well as its larger counterparts.