The dual mobility cup was introduced in the 1970s to allow extensive range of motion associated with great stability thanks to double articulation; the first between the head and polyethylene, the second between the polyethylene and the cup. The original plan was to install a stainless-steel uncemented cup coated with a thin layer of alumina and a metal head of 22,2 mm with a polyethylene liner of first generation. Long term follow-up case studies are cited in the literature showing excellent results in reducing dislocations; however wearing and aseptic loosening are noted. The new dual-mobility cups, with reticular polyethylene and titanium and hydroxyapatite coating are proving as reliable as the older ones in terms of stability whilst they appear to be more durable. Furthermore, cemented dual-mobility cups are available, these are the topic of this study. One of the most frequent complications in the major revisions of hip replacement is dislocation. This study summarises our experience gathered in the use of dual-mobility cups during revisions of complex cases (GIR III-IV femoral or acetabular). Between July 2014 to March 2015, we have implanted 13 cemented cups with dual-mobility (Avantage® Biomet) each in different patients, who have undergone revision with severe ostheolysis (GIR III-IV femoral or acetabular). The mean age of patients was 71.5 years old (46 to 89). Indications for revisions were: aseptic loosening in 7 patients (two at third surgery), recurrent dislocation in 3 patients, 1 septic loosening, 1 revision after spacer removal e 1 post-traumatic. We used dual-mobility cup in revision surgery when implant stability could have been compromised due to difficult positioning of acetabular component in cases of walls defects or muscolar laxity. The patients have been evaluated clinically and radiographically.Introduction
Materials and Methods
Periprosthetic joint infection (PJI) is considered one of the most feared causes of implant failure, due to the difficulty in formulating a proper and timely diagnosis. In the diagnostic workup are often used test with a low specificity, such as the dosage of ESR and CRP, or sensitivity, such as cultures or the leukocyte count of the synovial fluid. Radiological investigations are expensive and unreliable to play a direct role in the diagnosis of PJI. The alpha-defensin is an antimicrobial peptide released by neutrophils in response to pathogens and it is an ideal biomarker for the diagnosis of PJI. It is now possible to verify the presence of alpha-defensin in periprosthetic synovial fluid with an ELISA (Synovasure® PJI, Zimmer) that provides results in 10 minutes, with a sensitivity of 97% and a specificity of 96%, without being affected by systemic inflammatory diseases or by the assumption of antibiotics. The purpose of this study is to assess the applicability and reliability of Synovasure® PJI, correlating its results with microbiological analyzes, laboratory tests and imaging studies of the patient. Patients recruited are those who have undergone a previous total hip or knee arthroplasty where there is suspicion of PJI. The test can be performed either during surgery or during the diagnostic iter, through the execution of an arthrocentesis. The synovial fluid is partly used for Synovasure® PJI and partly put in culture for microbiological analyzes. Once ready, culture results are compared with the results of the test to get a confirmation of its reliability or reference to identify the microorganism responsible for PJI. These data are then compared, with laboratory tests and radiological investigations performed by the patient.Introduction
Materials and Methods
We present the mid-term results of our consecutive series of 155 hips treated with ASR XL Acetabular System (ASR-XL) for large-diameter metal-on-metal total hip arthroplasty and with DePuy ASR Hip Resurfacing System (ASR) for hip resurfacing. 114 ASR-XL and 41 ASR were implanted between 2004 and 2008 in 145 patients (69 men and 76 women) with a mean age of 57 years. Twenty-one patients (23 hips) resulted lost to follow-up. All patients were recalled and monitored periodically with clinical, hematological and radiological evaluation. Average follow-up of the 155 hips was 72 months (1 to 104). The mean follow-up, excluding revised patients and those lost to follow-up, was up to 89 months.Introduction:
Methods:
Second-generation metal-on-metal bearings have been used since the late 1980s as alternative bearings to eliminate aseptic loosening due to polyethylene wear. This study is the first with a long term follow-up for Meteasul, (Zimmer GmbH, Winterthur, Switzerland) metal on metal (MoM) hip replacement; in literature most of the studies have a mean follow-up of 7 years. Metasul showed better performances than other MoM couplings, with a low failure rate at long term follow-up and low revision rate for aspetic loosening. The aim of the present study was to evaluate the long-term results of a series of Metasul implanted between January 1993 and July 1997. 145 cementless THAs with a 28 mm Metasul articulation were performed in 114 consecutive patients. Implant survivorship was calculated and clinical and radiographic evaluations were performed on 93 hips still available for follow-up at a mean of 19 years postoperatively (43 hips are dead or lost to FU, 29, 6%). Nine hips (6.2%) were revised. The cumulative probability of survival of the overall implant at 19 years postoperatively with revision for any reason as the end point, was 0.937 (95% confidence interval, 0.888 to 0.985). The cumulative probability of survival of Metasul with revision for any reason as the end point, was 0.956 (95% confidence interval, 0.916 to 0.997). Clinical outcome has been evaluated with modified Harris Hip Score for 93 hips with an average of 88.8 points. Various degrees of radiolucencies and osteolysis were found proximally around the femoral components of 25 hips (20%). Most of the patients has normal serum levels of metal ions (Co and Cr), and no cases of systemic toxicity has been reported. Cementless Metasul THAs showed high probability of survival at 19 years postoperatively.
Previous studies have indicated poor outcomes and high complication rate in patients having revision of metal-on-metal (MoM) hip implants resulting from adverse local tissue reactions. Metal ions released by MoM bearings may potentially increase infection occurrence in patients with failed implants. We reviewed all patients at our institution who sustained revision of a failed large-head metal-on-metal hip implant to determine if infection-related complications are associated with the elevation of serum metal ions concentration.Background
Questions/purposes
The Gibson and Moore postero-lateral approach is one of the most often used in hip replacement. The advantage of this approach is an easy execution but it's criticized because of its invasivity to muscle-tendinous tissues especially on extrarotators muscles and because of predisposition to posterior dislocation. Since June 2003 we executed total hip replacements using a modified postero-lateral approach which allows to preserve the piriformis and quadratus femoris muscles and to detach just the conjoint tendon (gemelli and obturator internus). Articular capsule is preserved and it will be anatomically sutured at the end of the procedure as well as the conjoint tendon with two transossesous sutures. Piriformis and quadratus femoris muscles result untouched by this approach. We have executed 500 surgeries with this modified approach. We have used different stems (straight, anatomical, modular and short) and press fit acetabular cup with polyethylene or ceramic insert and we have always used 36 mm femoral heads when allowed by the cup dimensions. We have used any size both of stems and cups without limitation due to the surgical approach. The mean age is 61.8 y.o., 324 females and 176 males. Obese patients, hip dysplasia Crowe 3 and 4 and post traumatic arthrosis are exclusion factors for the execution of this approach. If possible we have maintained the capsulo-tendinous less invasivity. The BMI is not an excluding factor because it's just the gluteus region that is an important factor to decide if to execute or not a less invasive approach. Analyzing our 500 cases we didn't have any case of malpositioning of the stem in varus or valgus (more than 5°) and considering acetabular cup we had the tendency to position it in valgus position (not more than 40°) in the first 20 cases. No leg discrepancy more than 1 cm were observed. Intra-operative blood loss have been reduced of about 30 % and 50% in the post-operative. All the patients were able to active hip mobilization within the first day after surgery with a mean range of motion of 0-70°. The patients were mobilized the first day after surgery and 80% of them were able to assisted walk within second day after surgery. The mean time of stay in hospital was 6.8 days. After 4 weeks 98% of the patients were able to walk without crutches. One case of deep infection were evaluated and then solved with surgical debridement; no wound dehiscence. We had 1 case of anterior hip dislocation in dysplastic arthrosis due to a technical mistake. In 1 case we had femoral nerve palsy, then solved, probably because of anterior retractor malpositioning. We had 5 cases of piriformis muscle contracture without sciatic nerve palsy, then solved. We think that for total hip replacement this conservative postero-lateral approach, thanks to capsule-tendinous modification we have adopted, could be considered an anatomical approach, which doesn't present more dislocation risks compared to other approaches to the hip also thanks to the introduction of 36 mm femoral head that gives more stability and proprioceptiveness. Besides this approach gives the possibility of a shorter rehabilitation as seen above and it could be consider optimal for total hip replacement.
The Gibson and Moore postero-lateral approach is one of the most often used in hip replacement. The advantage of this approach is an easy execution but it’s criticized because of its invasivity to muscletendinous tissues especially on extrarotators muscles and because of predisposition to posterior dislocation. Since June 2003 we executed total hip replacements using a modified postero-lateral approach which allows to preserve the piriformis and quadratus femoris muscles and to detach just the conjoint tendon (gemelli and obturator internus). Articular capsule is preserved and it will be anatomically sutured at the end of the procedure as well as the conjoint tendon with two transossesous sutures. Piriformis and quadratus femoris muscles result untouched by this approach. We have executed 500 surgeries with this modified approach. We have used different stems (straight, anatomical, modular and short) and press fit cetabular cup with polyethylene or ceramic insert and we have always used 36 mm femoral heads when allowed by the cup dimensions. We have used any size both of stems and cups without limitation due to the surgical approach. The mean age is 61.8 y.o., 324 females and 176 males. Obese patients, hip dysplasia Crowe 3 and 4 and post traumatic arthrosis are exclusion factors for the execution of this approach. If possible we have maintained the capsulo-tendinous less invasivity. The BMI is not an excluding factor because it’s just the gluteus region that is an important factor to decide if to execute or not a less invasive approach. Analyzing our 500 cases we didn’t have any case of malpositioning of the stem in varus or valgus (more than 5°) and considering acetabular cup we had the tendency to position it in valgus position (not more than 40°) in the first 20 cases. No leg discrepancies more than 1 cm were observed. Intra-operative blood loss have been reduced of about 30 % and 50% in the post-operative. All the patients were able to active hip mobilization within the first day after surgery with a mean range of motion of 0–70°. The patients were mobilized the first day after surgery and 80% of them were able to assisted walk within second day after surgery. The mean time of stay in hospital was 6.8 days. After 4 weeks 98% of the patients were able to walk without crutches. One case of deep infection were evaluated and then solved with surgical debridement; no wound dehiscence. We had 1 case of anterior hip dislocation in dysplastic arthrosis due to a technical mistake. In 1 case we had femoral nerve palsy, then solved, probably because of anterior retractor malpositioning. We had 5 cases of piriformis muscle contracture without sciatic nerve palsy, then solved. We think that for total hip replacement this conservative postero-lateral approach, thanks to capsuletendinous modification we have adopted, could be considered an anatomical approach, which doesn’t present more dislocation risks compared to other approaches to the hip also thanks to the introduction of 36 mm femoral head that gives more stability and proprioceptiveness. Besides this approach gives the possibility of a shorter rehabilitation as seen above and it could be consider optimal for total hip replacement.
