In metal-on-polyethylene (MoP) THA large femoral metal heads are designed to increase stability and to reduce dislocation risk. The increased head size could lead to increased taper corrosion with the release of metal ions and adverse reactions. Using blood ion measurements, we aimed to investigate the association between femoral head size and metal-ion release after MoP THA. 96 patients were enrolled at two centers and randomized to receive either a 32-mm metal head or a 36–44 mm metal head (the largest possible fitting the thinnest available polyethylene insert). Blood metal ions and PROMs (OHS, UCLA) were measured at two- and five-year follow-ups. Both 2- and 5-year median chrome, cobalt, and titanium levels were below taper corrosion indicative ion levels. At 5 years, median chrome, cobalt, and titanium levels were 0.5 μg/L (0.50–0.62), 0.24 μg/L (0.18–0.30), and 1.16 μg/L (1.0–1.68) for the 32-mm group, and 0.5 μg/L (0.5–0.54), 0.23 μg/L (0.17–0.39), and 1.30 μg/L (1–2.05) for the 36–44 mm group, with no difference between groups 5 years after the insertion of MoP THAs, we found no differences in the blood metal ion levels between 32 mm heads and 36–44 mm heads and no corrosion-related revisions. As taper corrosion can debut after 5 years, there is still a need for long-term follow-up studies on the association between head size and corrosion in MoP THA.
Genetic skeletal disorders constitute a rare and heterogeneous bone diseases often leading to poor quality of life. Several surgical options are available. The surgeon must deal with specific features (bone deformity, previous procedures, abnormal bone quality, stiffness or instability, muscle weakness). The questions concern the feasibility of the procedures and the surgical strategy. 55 patients (26 W, 29 M) were reviewed between 2016 and 2022. The mean age of the patients was 35 years (17–71). The diagnosis included 9 hereditary multiple exostoses, 8 osteogenesis imperfecta, 6 multiple epiphyseal dysplasia congenita, 6 achondroplasia, 4 osteopetrosis, 3 pycnodysostosis, 3 hypophosphatemic rickets, 3 fibrous dysplasia, 2 mucopolysaccharidosis, and 10 miscellaneous. 25 patients were referred for hip problems (40 hips). 4 patients (7 hips) requiring a THA have not been operated (4 planned). 4 patients (6 hips) had a proximal femoral fixation (2 osteotomies, 4 fracture fixations). 17 patients (27 hips) sustained a THA (25 primary, 2 revisions). All of them were operated by one operator, using a posterolateral approach and standard implants (including 7 dysplastic and 2 short stems). No customized implant has been used. As regard the 27 THAs, the mean follow up was 4.2 years (1–12). The early complications included 2 femoral cracks and 1 femur fracture. There were 2 revisions (1 cup loosening at 2 years, 1 stem loosening at 4 years). No infection nor dislocation occurred. All the patients were satisfied with their treatment and regain some autonomy. 3 THA were considered as unfeasible. Constitutional bone diseases need a multidisciplinary program of care. The indication for surgery is based on a mutual trust patient/surgeon, a careful evaluation of benefits/risks, and an accurate imaging to anticipate the difficulties. The expected results are a better function and quality of life, and a stability over time.
Pelvic discontinuity (PD) is a detrimental complication following total hip arthroplasty (THA). The aim of this study was to assess the clinical and radiological results of patients with PD who were revised using a custom-made triflange acetabular component (CTAC). This is a single centre prospective study of patients with PD following THA who were treated with a CTAC. The Hip Disability and Osteoarthritis Outcome Score (HOOS), modified Oxford Hip Score (mOHS), EurQol five-dimension three-level (EQ-5D-3L) utility, and Numeric Rating Scale (NRS), including visual analogue score (VAS) for pain, were gathered at baseline, and at one- and two-year follow-up. Clinical and radiological complications, including reasons for revisions were registered. Trends over time are described and tested for significance and clinical relevance. 18 females with 22 CTACs were included with a mean age of 73.5 years (SD 7.7). There were significant improvements between baseline and final follow-up in HOOS (p<0.01), mOHS (p<0.01), EQ-5D-3L utility (p<0.01), EQ-5D-3L NRS (p<0.01), VAS pain rest (p<0.01), and VAS pain activity (p<0.01). A minimal clinically important improvement in mOHS and the HOOS was observed in 16 patients (73%) and 14 patients (64%), respectively. Definite healing of the PD was observed in 19 hips (86%). Complications included six cases with broken screws (27%), four cases (18%) with bony fractures, and one case (4.5%) with sciatic nerve paresthesia. One patient with concurrent bilateral PD had revision surgery due to recurrent dislocations. No revision surgery was performed for screw failure or implant breakage. This is the first prospective assessment in clinical outcome of patients with PD who were treated with a CTAC. We have demonstrated that CTAC in patients with THA acetabular loosening and PD can result in stable constructs with no mechanical failures. Moreover, clinically relevant improvements in health-related quality of life at two years’ follow-up was observed.
Cup-cage constructs are one of several methods commonly used to treat severe acetabular bone loss during contemporary revision total hip arthroplasty. The purpose of this study was to provide a long-term results of the technique with emphasis on implant survivorship, radiographic results, and clinical outcomes for both full and half cup-cage reconstructions. We identified 57 patients treated with a cup-cage reconstruction for major acetabular bone loss between 2002–2012. All patients had Paprosky Type 2B through 3B bone loss, with 60% having an associated pelvic discontinuity. Thirty-one patients received a full cup-cage construct, and 26 a half cup-cage. Mean age at reconstruction was 66 years, 75% were female, and the mean BMI was 27 kg/m2. Mean follow-up was 10 years. The 10-year cumulative incidences of any revision were 14% and 12% for the full and half cup-cage construct groups, respectively. Of the 9 revisions, 3 were for dislocation, 2 for aseptic loosening and construct failure (both were pelvic discontinuities), 1 for adverse local tissue reaction, and 1 for infection with persistent pelvic discontinuity. The 10-year cumulative incidences of revision for aseptic loosening were 4.5% and 5% for the full and half cup-cage constructs, respectively. Of the unrevised cases, incomplete and non-progressive zone 3 radiolucent lines were observed in 10% of patients in each group. Three patients experienced partial motor and sensory sciatic nerve palsies (2 in the full and 1 in the half cup-cage group). Both the full and half cup-cage cohorts demonstrated significantly improved Harris hip scores. Full and half cup-cage reconstructions for major acetabular defects were successful at 10 years in regards to acetabular fixation without appreciable differences between the two techniques. However, zone 3 radiolucent lines were not uncommon in association with discontinuities, and dislocation continues to be a problem.
Mechanical irritation or impingement of the iliopsoas tendon accounts for 2–6% of persistent postoperative pain cases after total hip arthroplasty (THA). The most common trigger is anterior cup overhang. CT-scan can be used to identify and measure this overhang; however, no threshold exists for symptomatic anterior iliopsoas impingement. We conducted a case–control study in which CT-scan was used to define a threshold that differentiates patients with iliopsoas impingement from asymptomatic patients after THA. We analyzed the CT-scans of 622 patients (758 CT-scans) between 2011 and 2020. Out of this population we identified 136 patients with symptoms suggestive of iliopsoas impingement. Among them, 6 were subsequently excluded: three because the diagnosis was reestablished intra-operatively (one metallosis, two anterior instability related to posterior prosthetic impingement) and three because they had another obvious cause of impingement (one protruding screw, one protruding cement plug, one stem collar), leaving 130 patients in the study (impingement) group. They were matched to a control group of 138 patients who were asymptomatic after THA. The anterior cup overhang (anterior margin of cup not covered by anterior wall) was measured by an observer (without knowledge of the clinical status) on an axial CT slice based on anatomical landmarks (orthogonal to pelvic axis). The impingement group had a median overhang of 8 mm [IQR: 5 to 11] versus 0 mm [IQR: 0 to 4] for the control group (p<.001). Using ROC curves, an overhang threshold of 4 mm was best correlated with a diagnosis of impingement (sensitivity 79%, specificity 85%, PPV = 75%, NPV = 85%). Pain after THA related to iliopsoas impingement can be reasonably linked to acetabular overhang if it exceeds 4 mm on a CT scan. Below this threshold, it seems logical to look for another cause of iliopsoas irritation or another reason for the pain after THA before concluding impingement is present.
In-hospital length of stay (LOS) and discharge disposition following arthroplasty could act as surrogate measures for improvement in patient pathways, and have major cost saving implications for healthcare providers. With the ever-growing adoption of robotic technology in arthroplasty, we wished to evaluate its impact on LOS. The objectives of this study were to compare LOS and discharge disposition following robotic-arm assisted (RO THA) versus conventional technique Total Hip Arthroplasty (CO THA). This large-scale, single institution study included patients of any age undergoing primary THA (N = 1,732) for any cause between May 2019 and January 2023. Data extracted included patient demographics, LOS, need for Post Anaesthesia Care Unit (PACU) admission, anaesthesia type, readmission within 30 days and discharge dispositions. Univariate and multivariate logistic regression models were also employed to identify factors and patient characteristics related to delayed discharge. The median LOS in the RO THA group was 54 hours (34, 78) versus 60 (51, 100) in the CO THA group, p<0.001. Discharge disposition was comparable between the two groups. In the multivariate model, age, need for PACU admission, ASA score > 2, female gender, general anaesthesia and utilisation of the conventional technique were significantly associated with LOS > 2 days. Our study showed that robotic-arm assistance was associated with a shorter LOS in patients undergoing primary THA and no difference in discharge destination. Our results suggest that robotic-arm assistance could be advantageous in partly addressing the upsurge of hip arthroplasty procedures and the concomitant health care burden; however, this needs to be corroborated by long-term cost effectiveness analyses and data from randomised controlled studies.
Majority of ultra-high molecular weight polyethylene (UHMWPE) medical devices used in total joint arthroplasty are crosslinked using gamma radiation to improve wear resistance. Alternative methods of crosslinking are urgently needed to replace gamma radiation due to rapid decline in its supply. Peroxide crosslinking is a candidate method with widespread industrial applications. Oxidative stability and biocompatibility, which are critical requirements for medical device applications, can be achieved using vitamin-E as an additive and by removing peroxide by-products through high temperature melting, respectively. We investigated compression molded UHMWPE/vitamin-E/di-cumyl peroxide blends followed by high-temperature melting in inert gas as a material candidate for tibial knee inserts. Wear resistance increased and mechanical properties remained largely unchanged. Oxidation induction time was higher than most of the other clinically available formulations. The material passed the local-end point biocompatibility tests per ISO 10993. Compounds found in exhaustive extraction were of no concern with margin-of-safety values well above the accepted level, indicating a desirable toxicological risk profile. Peroxide crosslinked, vitamin-E stabilized, and high temperature melted UHMWPE has recently been cleared for clinical use in tibial knee inserts. With all the salient characteristics needed in a material that can provide superior long-term performance in total joint patients, peroxide crosslinking can replace gamma radiation crosslinking of UHMWPE for use in all total joint replacement implant including acetabular liners.
Since 1977 we did implant ceramic on ceramic THR in younger and active population. In 1991 we published (JBJS B N°4) data's in a consecutive group of patients under 50 years of age. What about the same patients for more than 30 years? Eighty-six hips in 75 patients, 41 males 34 females, mean age 43 (18 to 50), mean weight 68 kg (36 to 100), Charnley class: 38 A, 28 (38 hips) B, 9 patients (10 hips) C. Sixty-six primary procedures, 20 revisions (18 failed arthroplasties: 6 THR, 5 resurfacing, four single cup, two hemiarthroplasty, one bipolar), one after acetabular fractures. Four hips previously infected. Eight Patients deceased (8 hips) prosthesis still in place, ten lost to follow-up before 2 years, eight hips in 8 patients were revised before the review, partially followed: from 2 to 20 years: 35, completely followed: 25 hips in 23 patients resuming in: No pain in 20, slight pain in 2, severe disability in 3 not related to the hip, no radiolucent lines in 22, radiolucent lines in 3, no osteolysis in 25. Revision for: early sepsis in one, socket loosening in 8 (3 revisions cases), femoral head fractures in 2: one extra small head (22mm) for Crowe 3 DDH, one fractured at 24 years. Inertness, stability related to fibrous tissue generation, no noise.
Dual mobility cups (DMC) reduce the risk of dislocation in femoral neck fractures (FNF). Direct anterior approach (DAA), historically promoted for better stability, has been developed in recent years for better functional results. The aim of this study was to compare the early functional results of DMC in FNF by DAA versus posterolateral approach (PLA). A prospective study was conducted on a continuous series of patients who received DMC for FNF by DAA or PLA. The primary endpoint was Harris Hip Score and Parker score assessed at the first follow-up visit. Intraoperative complications were collected during hospitalization. One year clinical results and all cause revision rate were also collected. Radiographic data of cup positioning and limb length were evaluated. Fifty-two patients were included in the DAA group and 54 in the PLA group. Two patients were lost to follow-up. The mean age was 72.8 years. There was no significant difference in HHS or Parker score at 3 and 12 months follow up (p=0.6, p= 0.75). DAA was associated with more intraoperative complications with 4 fractures and 1 femoral nerve deficit (p=0.018). There were 3 revisions in the DAA group (1 infection, 1 dislocation, 1 peri prosthetic fracture) and 1 in the PLA group (infection), which was not statistically significant (p=0.34). Cup anteversion was 6° greater and inclination 9° lesser in DAA group (p=0.028, p<0.01). Results suggest that DAA does not provide any early functional benefit in THA-DMC for FNF compared to PLA. It could lead to more intraoperative complications and a higher revision rate. DAA requires an experienced surgeon and careful patient selection.
The aim of the study was to evaluate radiological and clinical outcomes of surgical treatment of developmental dysplasia of the hip (DDH) with Periacetabular Osteotomy (PAO) and to determine the values of radiological parameters allowing us to obtain an optimal clinical result. Radiological evaluation included a standardized AP digital radiograph of the hip joints. Centre edge angle (CEA), medialization, distalization, femoral head coverage (FHC) and ilioischial angle were measured. Clinical evaluation based on HHS, WOMAC, Merle d'Aubigne-Postel scales and Hip Lag Sign. Radiological and clinical evaluation was performed preoperatively and approximately 12 months after the surgery. Statistically significant (p<0.05) differences in radiological measurements and all clinical scales have been observed pre- and postoperatively for all of the parameters. The results of PAO presented decreased medialization by 3.4mm (range: 3 to 3.7), distalization by 3.5mm (range: 3.2 to 3.8) and the ilioischial angle by 2.7° (range: 2.2 to 3.7). There was also an improvement in the femoral head bone coverage: CEA increased by 16.3° (range: 12.1˚ to 20.5˚) and FHC by 15.2% (range: 10.8 to 19.8). Clinically we observed an increase in HHS by 22 points (range: 15.8 to 28.2) and M. Postel d'Aubigne by 3.5 points (range: 2.0 to 4.4) and a decrease in WOMAC by 24% (range: 22.6 to 25.8). HLS improvement of gluteal muscles’ efficiency has been observed in 67% of patients postoperatively. This study revealed that the qualification of patients with DDH for an elective PAO is more justified due to the predicted optimal clinical outcomes based on three parameters: CEA <25 degrees, FHC <75%, and ilioischial angle >85.9 degrees. Accordingly, to achieve better clinical results for all scales, it is necessary to increase the average CEA value by 11˚, the average FHC by 11%, and reduce the average ilioischial angle by 3˚.
Finite element analysis (FEA) has been applied for the biomechanical analysis of acetabular dysplasia, but not for biomechanical studies of periacetabular osteotomy (PAO) or those performing analysis taking into consideration the severity of acetabular dysplasia. This study aimed to perform biomechanical evaluation of changes in stress distribution following PAO and to determine the effect of the severity of developmental dysplasia of the hip (DDH) using three-dimensional FEA. A normal model was designed with a 25° center-edge (CE) angle and a 25° vertical-center-anterior margin (VCA) angle. DDH models were designed with CE and VCA angles each of 10, 0, or −10°. Post-PAO models were created by separating each DDH model and rotating the acetabular bone fragment in the anterolateral direction so that the femoral head was covered by the acetabular bone fragment, with CE and VCA angles each at 25°. Compared to the normal hip joint model, the DDH models showed stress concentration in the acetabular edge and contacting femoral head, and higher stress values; stress increased with decreasing CE and VCA angles. Compared to the DDH models, the post-PAO models showed near-normal patterns of stress distribution in the acetabulum and femoral head, with stress concentration areas shifted from the lateral to medial sides. Stress dispersion was especially apparent in the severe acetabular dysplasia models. PAO provided greater decreases in the maximum values of von Mises stress in the load-bearing area of the acetabulum and femoral head when applied to the DDH models of higher degrees of severity, although the values increased with increasing severity of DDH. PAO is expected to provide biomechanical improvement of the hip joint, although the results also suggest a limitation in the applicability of PAO for the patients with severe acetabular dysplasia.
To evaluate the effects of 6 and 18 months of abaloparatide (ABL) compared with placebo (PBO) on bone mineral density (BMD) in the acetabular regions of postmenopausal women with osteoporosis (OP). Acetabular bone loss, as may occur in OP, increases risk of acetabular fragility fracturesa. In total hip arthroplasty (THA), low acetabular BMD adversely affects primary stability, osseointegration, and migration of acetabular cups.c ABL is an osteoanabolic agent for the treatment of men and postmenopausal women with OP at high risk for fracture. Effects of ABL on acetabular BMD are unknown. Hip DXA scans were obtained at baseline, 6, and 18 months from a random subgroup of postmenopausal women (aged 49–86 y) from the phase 3 ACTIVE trial randomized to either ABL 80 µg/d or PBO (n=250/group). Anatomical landmarks were identified in each DXA scan to virtually place a hemispherical shell model of an acetabular cup and define regions of interest corresponding to DeLee & Charnley zones 1 (R1), 2 (R2), and 3 (R3). BMD changes compared to baseline were calculated for each zone. Statistical BMD in all zones were similar at baseline in the ABL and PBO groups. BMD significantly increased in the ABL group at 6 and 18 months compared with PBO (all ABL treatment resulted in rapid and progressive increases in BMD of all 3 acetabular zones. Increasing acetabular BMD has the potential to improve acetabular strength, which may reduce risk of acetabular fragility fractures. In bone health optimization prior to THA, increased acetabular BMD via ABL may provide better primary stability and longevity of acetabular cups in postmenopausal women with OP.
Sound management decisions are critical to outcomes in revision arthroplasty. Aiming to improve outcomes, revision networks facilitate speciality trained, high volume surgeons, share experience and best practice, contributing to decision making within and away from their base hospital. We have reported the early clinical experience of East Midlands Specialist Orthopaedic Network (EMSON). In this paper we report beneficial clinical effects, both demonstrable and unquantifiable supporting the process. Using the UK HES database of revisions, performed before and after EMSON was established, (April 2011 – March 2018), data from EMSON hospitals were compared to all other hospitals in the same time-period. Primary outcome was re-revision surgery within 1 year. Secondary outcomes were re-revision, complications within first two years and median LOS. 57,621 RTHA and 33,828 RTKA procedures were involved with around 1,485 (2.6%) and 1,028 (3.0%) respectively performed within EMSON. Re-revision THA rates, within 1 year, in EMSON were 7.3% and 6.0% with re-revision knee rates 11.6% and 7.4%, pre- and post-intervention. Re-revision rates in the rest England in the same periods were 7.4% to 6.8% for hips and 11.7% to 9.7% for knees. This constituted a significant improvement in 1-year re-revision rates for EMSON knees. (β = −0.072 (−0.133 to −0.01), p = 0.024). The reduction in hip re-revision did not reach statistical significance. Secondary outcomes showed a significant improvement for 1 and 2-year RTHA complication rates. Re-revision rates for RTKA and complication rates for RTHA improved significantly after the introduction of EMSON. Other outcomes studied also improved to a greater extent in the network hospitals. While anecdotal experience with networks is positive, the challenge in collating data to prove clinic benefit should not be underestimated. Beyond the formal process, additional communication, interaction, and support has immeasurable benefit in both elective and emergency scenarios.
Previous reports on the outcomes of isolated head and liner exchange in revision total hip arthroplasty have found high rates of instability following these surgeries. Most reports have studied constructs using ≤28mm femoral heads. The purpose of this study was to determine if modern techniques with the use of larger head sizes can improve the rate of instability after head and liner exchange. We identified 138 hips in 132 patients who underwent isolated head and liner exchange for polyethylene wear/osteolysis (57%), acute infection (27%), metallosis (13%), or other (2%). All patients underwent revision with either 32mm (23%), 36mm (62%), or 40mm (15%) diameter heads. Crosslinked polyethylene was used in all revisions. Lipped and/or offset liners were used in 104 (75%) hips. Average follow up was 3.5 (1.0–9.1) years. Statistical analyses were performed with significance set at p<0.05. Revision-free survivorship for any cause was 94.6% and for aseptic causes was 98.2% at 5 years. 11 (8%) hips experienced a complication with 7 (5%) hips requiring additional revision surgery. Following revision, 4 (3%) hips experienced dislocation, 5 (4%) hips experienced infection, and 1 (1%) hip was revised for trunnionosis. No demographic or surgical factors significantly affected outcomes. Our study shows that isolated head and liner exchange using large femoral heads and modern liners provides for better stability than previous reports. The most common complication was infection. We did not identify specific patient, surgical or implant factors that reduced the risk of instability or other complication.
The interest in day-case hip arthroplasty is increasing; however, there are conflicting results regarding readmission risk, and little is known about patients’ attitude towards day-case surgery. We aimed to investigate differences in 30-day readmission rates between day-case patients and single-overnight-stay patients following total hip arthroplasty (THA) and explore patients’ attitude towards day-case surgery. From the Danish National Patient Register we identified 29,486 THAs (1353 day-case THAs and 28,133 single-overnight-stay THAs) performed between 2010 and 2020. Day-case surgery was defined as discharge on the day-of-surgery. Overnight admissions within 30 days of surgery were considered readmissions. Differences in readmission rates between day-case and single-overnight-stay patients were investigated using logistic regression adjusted for patient characteristics and year of surgery. In a single-center descriptive study, 2395 hip arthroplasty patients from 2016 to start-2023 answered a questionnaire on patient characteristics, attitude towards day-case surgery and patient-reported outcome measures (PROM). The overall 30-day readmission rate was 4.4% (CI: 4.2–4.6%) with no difference between day-case (4.4%) and single-overnight-stay THAs (4.4%) (odds-ratio: 1.2 [CI: 0.91–1.6]). In the descriptive study answers to the question whether patients were interested in being discharged on the day of surgery, were: “Yes” = 41%, “Do not know” = 20%, “No” = 39%. Patients responding “No” had lower preoperative PROM-scores, were older (“No” = 70.2 y vs. “Yes” = 65.3 y), and more often female (“No” = 72% vs. “Yes” = 52% female). Based on nationwide data from 2010–2020, day-case THA patients were not more likely to be readmitted compared to single-overnight-stay patients. However, most patients were not positive towards day-case surgery. While surgeons may consider day-case surgery to be safe, patients are not intuitively positive, indicating an attitude mismatch. To achieve high success rate and patient satisfaction in day-case surgery, shared-decision making initiatives within day-case surgery are needed.
Pelvic discontinuity is a separation through the acetabulum with the ilium displacing superiorly and the ischium/pubis displacing inferiorly. This is a biomechanically challenging environment with a high rate of failure for standard acetabular components. The cup-cage reconstruction involves the use of a highly porous metal cup to achieve biological bone ingrowth on both sides of the pelvic discontinuity and an ilioischial cage to provide secure fixation across the discontinuity and bring the articulating hip center to the correct level. The purpose of this study was to report long term follow up of the use of the cup-cage to treat pelvic discontinuity. All hip revision procedures between January 2003 and January 2022 where a cup-cage was used for a hip with a pelvic discontinuity were included in this retrospective review. All patients received a Trabecular Metal Revision Shell with either a ZCA cage or TMARS cage (Zimmer-Biomet Inc.). Pelvic discontinuity was diagnosed on pre-operative radiographs and/or intraoperatively. Kaplan-Meier survival analysis was performed with failure defined as revision of the cup-cage reconstruction. Fifty-seven cup-cages in 56 patients were included with an average follow-up of 6.25 years (0.10 to 19.98 years). The average age of patients was 72.09 years (43 to 92 years) and 70.2% of patients were female. The five year Kaplan-Meier survival was 92.0% (95% CI 84.55 to 99.45) and the ten year survival was 80.5% (95% CI 58.35 to 102.65). There were 5 major complications that required revision of the cup-cage reconstruction (3 infections and 2 mechanical failures). There were 9 complications that required re-operation without revision of the cup-cage reconstruction (5 dislocations, 3 washouts for infection and one femoral revision for aseptic loosening). In our hands the cup-cage reconstruction has provided a reliable tool to address pelvic discontinuity with an acceptable complication rate.
Osteolysis, fractures, and bone destruction caused by osteomyelitis or metastasis can cause large bone defects and present major challenges during acetabular reconstruction in total hip arthroplasty. We sought to evaluate the survivorship and radiographic outcomes of an acetabular reconstruction consisting of a polyethylene liner (semi-constrained) embedded in cement filling bone defect(s) reinforced with screws and/or plates for enhanced fixation (HiRISC). Retrospective chart review of 59 consecutive acetabular reconstructions as described above performed by 4 surgeons in a single institution (10/18/2018-1/5/2023) was performed. After radiographs and operative reports were reviewed, cases were classified following the Paprosky classification for acetabular defects. Paprosky type 1 cases (n=26) were excluded, while types 2/3 (n=33) were included for analysis. Radiographic loosening was evaluated up to latest follow-up. Mean follow-up was: 487 days (range, 20–1,539 days). Out of 33 cases, 2 (6.1%) cases were oncological (metastatic disease) and 22 (66.7%) had deep infection diagnosis (i.e., periprosthetic joint infection [PJI] or septic arthritis). In total, 7 (21.2%) reconstructions were performed on native acetabula (3 septic, 4 aseptic). At a mean follow-up of 1.3 years, 5 (15.2%) constructs were revised: 4 due to uncontrolled infection (spacer exchange) and 1 for instability. On follow-up radiographs, only 1 non-revised construct showed increased radiolucencies, but no obvious loosening. When compared to patients with non-revised constructs, those who underwent revision (n=5) were significantly younger (mean 73.8 vs. 60.6 years, p=0.040) and had higher body mass index (24.1 vs. 31.0 Kg/m2, p=0.045), respectively. Sex, race, ethnicity, American-Society-of-Anesthesiologist classification, infection diagnosis status (septic/aseptic), and mean follow-up (449.3 vs. 695.6 days, respectively, p=0.189) were not significantly different between both groups. HiRISC construct may be a viable short-term alternative to more expensive implants to treat large acetabular defects, particularly in the setting of PJI. Longer follow up is needed to establish long term survivorship.
Previous studies have reported excellent results with tapered, titanium alloy, porous plasma-sprayed components in patients undergoing uncemented primary total hip arthroplasty (THA). The purpose of this study was to examine survival and clinical results at minimum 25-year follow-up. We reviewed all patients who underwent primary THA at our center through 1995 with a specific femoral component, the Mallory-Head Porous (MHP; Zimmer Biomet, Warsaw, IN). This device, marketed in the U.S. until December 2021, was essentially unchanged since its 1984 introduction, except the porous coating was continued circumferentially along the lateral aspect in 1987, a hydroxyapatite-coated option was offered in 1988, and an offset option was added in 1999 after the study period. Three hundred thirty-two patients (396 THA) had a minimum of 25-year follow-up. Mean age at surgery was 47.6 years (range, 21–70 years). Mean follow-up in non-failed patients was 28.7 years (range, 25 to 37 years). There were 31 femoral revisions (7.8%): 9 infection, 3 failure of ingrowth, 5 aseptic loosening, 8 osteolysis revised well-fixed, 2 periprosthetic fracture, 2 polyethylene wear with trochanteric avulsion, 1 component breakage, and 1 malalignment well-fixed. Kaplan-Meier survival with endpoint of stem revision for all causes was 94.8% (95% CI: ±0.9%) at 36.7 years, and survival with endpoint of aseptic loosening/failure of ingrowth was 98.7% (95% CI: ±0.5) at 36.7 years. Harris hip scores improved significantly from 43 preoperatively to 76 most recently. This tapered, titanium, porous plasma spray-coated femoral component continues to demonstrate high long-term survival with a low rate of femoral component revision for any reason or aseptic loosening/failure of ingrowth.
The trend towards more minimal access has led to a series of instruments being developed to enable adequate access for Direct Anterior Approach (DAA) for hip arthroplasty. These include longer levers, hooks attached to the operating table and a series of special attachments to the operating table to position the leg and apply traction where necessary. The forces applied in this way may be transmitted locally, damaging muscle used as a fulcrum, or the knee and ankle joints when torque has to be applied to the femur through a boot. The arthroplasty surgeon's aim is to minimise the forces applied to both bone and soft tissue during surgery. We surmised that the forces needed for adequate access were related to the extent of the capsular and soft tissue releases, and that they could be measured and optimised. with the aim of minimising the forces applied to the tissues around the hip. Eight fresh frozen specimens from pelvis to mid tibia from four cadavers were approached using the DAA. A 6-axis force/torque sensor and 6-axis motion tracking sensor were attached to a threaded rod securely fastened to the tibial and femoral diaphysis. The torque needed to provide first extension, then external rotation, adequate for hip arthroplasty were measured as the capsular structures were divided sequentially. The Zona Orbicularis (ZO) and Ischiofemoral Ligament(IFL) contributed most of the resistance to both extension (4.0 and 3.1Nm) and external rotation torque (5.8 and 3.9Nm). The contributions of the conjoint tendon (1.5 and 2.4Nm) and piriformis (1.2 and 2.3Nm) were substantially smaller. By releasing the Zona Orbicularis and Ischiofemoral Ligament, the torque needed to deliver the femur for hip arthroplasty could be reduced to less than the torque needed to open a jar (2.9–5.5Nm).
At the end of 2018, the NZ Joint Registry introduced a “Surgeon Outlier” policy, whereby each year, if an individual surgeons’ lower 95% confidence interval of their revision rate, measured in revision/100 component years(r/ocys), was above the NZ mean (0.71 r/ocys), that surgeon was required to audit their results with a nominated peer. This study investigates whether outlier surgeons also have high early (1 month and 1 year) revision rates. In 2018, 236 surgeons performed 9,186 total hip arthroplasties in NZ. At the end of 2018, 11 surgeons received notification they were outliers. Results from all surgeons for years 2016, 2017 and 2018 were combined to form the first (pre-notification) time interval, and results from years 2019, 2020 and 2021 were combined to form the second time interval (post-notification). Outlier surgeons performed 2001 total hip replacements in the first time interval and 1947 hips in the second. Early revision rates (1 month and 1 year) of both outlier and nonoutlier surgeons for both time intervals were analysed. Non-outlier surgeons had a consistent mean early revision rate of 0.75% at one month and 1.6% at one year for both time intervals. The 11 outlier surgeons had a higher earlier revision rate of 1.35% at one month and 2.45% at one year for the pre-notification time interval. These values reduced for the post-notification time interval to a revision rate of 1.23% for one month and 2.36% for one year. Poor joint registry results of individual surgeons are often attributed to a poor choice of prosthesis. This study shows early revision rates of outlier surgeons, where prosthesis selection has minimal influence, are also high. A slight improvement in early revision rates of outlier surgeons since introduction of the policy shows it is working.
