Understanding spinopelvic mechanics is important for the success of total hip arthroplasty (THA). Despite significant advancements in appreciating spinopelvic balance, numerous challenges remain. It is crucial to recognize the individual variability and postoperative changes in spinopelvic parameters and their consequential impact on prosthetic component positioning to mitigate the risk of dislocation and enhance postoperative outcomes. This review describes the integration of advanced diagnostic approaches, enhanced technology, implant considerations, and surgical planning, all tailored to the unique anatomy and biomechanics of each patient. It underscores the importance of accurately predicting postoperative spinopelvic mechanics, selecting suitable imaging techniques, establishing a consistent nomenclature for spinopelvic stiffness, and considering implant-specific strategies. Furthermore, it highlights the potential of artificial intelligence to personalize care.

Cite this article: Bone Joint J 2024;106-B(11):1206–1215.

Aims

Custom-made partial pelvis replacements (PPRs) are increasingly used in the reconstruction of large acetabular defects and have mainly been designed using a triflange approach, requiring extensive soft-tissue dissection. The monoflange design, where primary intramedullary fixation within the ilium combined with a monoflange for rotational stability, was anticipated to overcome this obstacle. The aim of this study was to evaluate the design with regard to functional outcome, complications, and acetabular reconstruction.

The objective of this study was to assess the clinical and radiological results of patients who were revised using a new generation custom-made triflange acetabular component (CTAC) for component loosening and large acetabular defect (Paprosky 3A and 3B) after previous total hip arthroplasty (THA). New generation CTACs involve the use of patient-specific drill guides and incorporate three-dimensional printed bone models, enhancing precision during surgical implantation. Data were extracted from a single centre prospective database of patients with large acetabular defects who were treated with a new generation CTAC. Patients were included if they had a minimum follow-up of five years. The modified Oxford Hip Score (mOHS), EurQol EuroQoL 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 two- and five-year follow-up. Reasons for revision, and radiological and clinical complications were registered. Trends over time are described and tested for significance (p<0.05). A total of 49 (70%) of 70 patients with a mean age of 73.5 years (SD 7.7) had a complete follow-up of 5 years. A significant improvement was found in HOOS, mOHS, EQ-5D-3L utility and NRS, VAS pain rest and activity between baseline and final follow-up. Complications included 8 cases with loosening screws, 4 with bony fractures, 4 periprosthetic infections and 2 cases with dislocation. One patient with bilateral pelvic discontinuity had revision surgery due to recurrent dislocations. No revision surgery was performed for screw failure or implant breakage. New generation CTAC in patients with THA acetabular loosening and massive acetabular bone loss (Paprosky 3A and 3B) can result in stable constructs and significant improvement in functioning and health-related quality of life at five years’ follow-up

Chronic pelvic discontinuity (CPD) during revision hip arthroplasty is a challenging entity to address. The aim of this study was to evaluate the clinical and radiologic outcomes, and complications of the “acetabular distraction technique” for the management of CPD during revision hip arthroplasty. Patients with CPD, who underwent acetabular revision between 2014 and 2022 at two tertiary care centres, using an identical distraction technique, were evaluated. Demographic parameters, pre-operative acetabular bone loss, duration of follow-up, clinical and radiologic outcomes, and survivorship were evaluated. In all, 46 patients with a mean follow-up of 34.4 (SD=19.6, range: 24–120) months were available for evaluation. There were 25 (54.3%) male, and 21 (45.7%) female patients, with a mean age of 58.1 (SD=10.5, range: 40–81) years at the time of revision surgery. Based on the Paprosky classification of acetabular bone loss, 19 (41.3%), 12 (26.1%), and 15 (32.6%) patients had type 3b, 3a, and 2c defects. All patients were managed using the Trabecular Metal™ Acetabular Revision System; 16 patients required additional Trabecular Metal™ augments. The mean HHS improved from 50.1 (SD=7.6, range: 34.3 – 59.8) pre-operatively, to 86.6 (SD=4.2, range: 74.8 -91.8) at the last follow-up. Two patients (4.3 %) developed partial sciatic nerve palsy, two (4.3%) had posterior dislocation, and one (2.2%) required re-revision for aseptic loosening. Radiologically, 36 (78.3%) patients showed healing of the pelvic discontinuity. The Kaplan-Meier construct survivorship was 97.78% when using re-revision for aseptic acetabular loosening as an endpoint. The acetabular distraction technique has good clinical and radiologic outcomes in the management of CPD during revision hip arthroplasty

Aims

The use of a porous metal shell supported by two augments with the ‘footing’ technique is one solution to manage Paprosky IIIB acetabular defects in revision total hip arthroplasty. The aim of this study was to assess the medium-term implant survival and radiological and clinical outcomes of this technique.

Aims. The aims of this study were to determine the success of a reconstruction algorithm used in major acetabular bone loss, and to further define the indications for custom-made implants in major acetabular bone loss. Methods. We reviewed a consecutive series of Paprosky type III acetabular defects treated according to a reconstruction algorithm. IIIA defects were planned to use a superior augment and hemispherical acetabular component. IIIB defects were planned to receive either a hemispherical acetabular component plus augments, a cup-cage reconstruction, or a custom-made implant. We used national digital health records and registry reports to identify any reoperation or re-revision procedure and Oxford Hip Score (OHS) for patient-reported outcomes. Implant survival was determined via Kaplan-Meier analysis. Results. A total of 105 procedures were carried out in 100 patients (five bilateral) with a mean age of 73 years (42 to 94). In the IIIA defects treated, 72.0% (36 of 50) required a porous metal augment; the remaining 14 patients were treated with a hemispherical acetabular component alone. In the IIIB defects, 63.6% (35 of 55) underwent reconstruction as planned with 20 patients who actually required a hemispherical acetabular component alone. At mean follow-up of 7.6 years, survival was 94.3% (95% confidence interval 97.4 to 88.1) for all-cause revision and the overall dislocation rate was 3.8% (4 of 105). There was no difference observed in survival between type IIIA and type IIIB defects and whether a hemispherical implant alone was used for the reconstruction or not. The mean gain in OHS was 16 points. Custom-made implants were only used in six cases, in patients with either a mega-defect in which the anteroposterior diameter > 80 mm, complex pelvic discontinuity, and massive bone loss in a small pelvis. Conclusion. Our findings suggest that a reconstruction algorithm can provide a successful approach to reconstruction in major acetabular bone loss. The use of custom implants has been defined in this series and accounts for < 5% of cases. Cite this article: Bone Joint J 2024;106-B(5 Supple B):47–53

Aims

Instability is a common indication for revision total hip arthroplasty (THA). However, even after the initial revision, some patients continue to have recurrent dislocation. The aim of this study was to assess the risk for recurrent dislocation after revision THA for instability.

The advent of modular porous metal augments has ushered in a new form of treatment for acetabular bone loss. The function of an augment can be seen as reducing the size of a defect or reconstituting the anterosuperior/posteroinferior columns and/or allowing supplementary fixation. Depending on the function of the augment, the surgeon can decide on the sequence of introduction of the hemispherical shell, before or after the augment. Augments should always, however, be used with cement to form a unit with the acetabular component. Given their versatility, augments also allow the use of a hemispherical shell in a position that restores the centre of rotation and biomechanics of the hip. Progressive shedding or the appearance of metal debris is a particular finding with augments and, with other radiological signs of failure, should be recognized on serial radiographs. Mid- to long-term outcomes in studies reporting the use of augments with hemispherical shells in revision total hip arthroplasty have shown rates of survival of > 90%. However, a higher risk of failure has been reported when augments have been used for patients with chronic pelvic discontinuity. Cite this article: Bone Joint J 2024;106-B(4):312–318

Aims

To investigate the extent of bone development around the scaffold of custom triflange acetabular components (CTACs) over time.

Aims

Dislocation remains a leading cause of failure following revision total hip arthroplasty (THA). While dual-mobility (DM) bearings have been shown to mitigate this risk, options are limited when retaining or implanting an uncemented shell without modular DM options. In these circumstances, a monoblock DM cup, designed for cementing, can be cemented into an uncemented acetabular shell. The goal of this study was to describe the implant survival, complications, and radiological outcomes of this construct.

Aims

Achieving accurate implant positioning and restoring native hip biomechanics are key surgeon-controlled technical objectives in total hip arthroplasty (THA). The primary objective of this study was to compare the reproducibility of the planned preoperative centre of hip rotation (COR) in patients undergoing robotic arm-assisted THA versus conventional THA.

Aims

The burden of revision total hip arthroplasty (rTHA) continues to grow. The surgery is complex and associated with significant costs. Regional rTHA networks have been proposed to improve outcomes and to reduce re-revisions, and therefore costs. The aim of this study was to accurately quantify the cost and reimbursement for a rTHA service, and to assess the financial impact of case complexity at a tertiary referral centre within the NHS.

The use of trabecular metal (TM.) shells supported by two TM augments in the footing technique has been described as a potential option for the treatment of Paprosky 3B acetabular defects. The aim of this study was to assess the mid implant survivorship and radiological and clinical outcomes after acetabular revision using this technique. We undertook a retrospective, double-centre series of 39 hips in 39 patients (15 male, 24 female) treated with the footing technique using a TM shell supported by two TM augments, for severe acetabular bone loss between 2007 and 2020. The mean age at the time of surgery was 62,9 (28 to 86) years. The mean follow-up was 5,4 (1,5 to 15) years. The cumulative mid survivorship of the implant with revision for any cause was 89%. 3 hips (7,6%) required further revision due to aseptic loosening, and 1 (2,8%) required revision for infection. The mean Harris Hip Score improved significantly from 48 (29 to 65) preoperatively to 79 points (62 to 98) at the latest follow-up (p < 0.001). The reconstruction of Paprosky 3B acetabular defects with TM shells and two augments in footing-technique showed excellent mid-term results. This technique appears to be a viable option for treating these defects

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/m. 2. 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

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 fractures. a. 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 P values were based on a repeated mixed measures model. 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 P<0.0001 vs PBO). BMD in the PBO group was relatively stable over time. 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

Contemporary acetabular reconstruction in major acetabular bone loss often involves the use of porous metal augments, a cup-cage construct or custom implant. The aims of this study were: To determine the reproducibility of a reconstruction algorithm in major acetabular bone loss. To determine the subsequent success of reconstruction performed in terms of re-operation, all-cause revision and Oxford Hip Score (OHS) and to further define the indications for custom implants in major acetabular bone loss. Consecutive series of Paprosky Type III defects treated according to a reconstruction algorithm. IIIA defects were planned to use a superior augment and hemispherical cup. IIIB defects were planned to receive either augment and cup, cup-cage or custom implant. 105 procedures in cohort 100 patients (5 bilateral) with mean age 73 years (42–94). IIIA defects (50 cases) − 72.0% (95%CI 57.6–82.1) required a porous metal augment the remainder treated with a hemispherical cup alone. IIIB defects (55 cases) 71.7% (95%CI 57.6–82.1) required either augments or cup-cage. 20 patients required a hemispherical cup alone and 6 patients received a custom-made implant. Mean follow up of 7.6 years. 6 re-revisions were required (4 PJI, 2 peri-prosthetic fractures & 1 recurrent instability) with overall survivorship of 94.3% (95% CI 97.4–88.1) for all cause revision. Single event dislocations occurred in 3 other patients so overall dislocation rate 3.8%. Mean pre-op OHS 13.8 and mean follow-up OHS 29.8. Custom implants were used in: Mega-defects where AP diameter >80mm, complex discontinuity and massive bone loss in a small pelvis (i.e., unable to perform cup-cage). A reconstruction algorithm can >70% successfully predict revision construct which thereafter is durable with a low risk of re-operation. Jumbo cup utilized <1/3 of cases when morphology allowed. The use of custom implants has been well defined in this series and accounts for <5% of cases

Aims. It has been well documented in the arthroplasty literature that lumbar degenerative disc disease (DDD) contributes to abnormal spinopelvic motion. However, the relationship between the severity or pattern of hip osteoarthritis (OA) as measured on an anteroposterior (AP) pelvic view and spinopelvic biomechanics has not been well investigated. Therefore, the aim of the study is to examine the association between the severity and pattern of hip OA and spinopelvic motion. Methods. A retrospective chart review was conducted to identify patients undergoing primary total hip arthroplasty (THA). Plain AP pelvic radiographs were reviewed to document the morphological characteristic of osteoarthritic hips. Lateral spine-pelvis-hip sitting and standing plain radiographs were used to measure sacral slope (SS) and pelvic femoral angle (PFA) in each position. Lumbar disc spaces were measured to determine the presence of DDD. The difference between sitting and standing SS and PFA were calculated to quantify spinopelvic motion (ΔSS) and hip motion (ΔPFA), respectively. Univariate analysis and Pearson correlation were used to identify morphological hip characteristics associated with changes in spinopelvic motion. Results. In total, 139 patients were included. Increased spinopelvic motion was observed in patients with loss of femoral head contour, cam deformity, and acetabular bone loss (all p < 0.05). Loss of hip motion was observed in patients with loss of femoral head contour, cam deformity, and acetabular bone loss (all p < 0.001). A decreased joint space was associated with a decreased ΔPFA (p = 0.040). The presence of disc space narrowing, disc space narrowing > two levels, and disc narrowing involving the L5–S1 segment were associated with decreased spinopelvic motion (all p < 0.05). Conclusion. Preoperative hip OA as assessed on an AP pelvic radiograph predicts spinopelvic motion. These data suggest that specific hip osteoarthritic morphological characteristics listed above alter spinopelvic motion to a greater extent than others. Cite this article: Bone Joint J 2023;105-B(5):496–503

The computational modelling and 3D technology are finding more and more applications in the medical field. Orthopedic surgery is one of the specialties that can benefit the most from this solution. Three case reports drawn from the experience of the authors’ Orthopedic Clinic are illustraded to highlight the benefits of applying this technology. Drawing on the extensive experience gained within the authors’ Operating Unit, three cases regarding different body segments have been selected to prove the importance of 3D technology in preoperative planning and during the surgery. A sternal transplant by allograft from a cryopreserved cadaver, the realization of a custom made implant of the glenoid component in a two-stage revision of a reverse shoulder arthroplasty, and a case of revision on a hip prosthesis with acetabular bone loss (Paprosky 3B) treated with custom system. In all cases the surgery was planned using 3D processing software and models of the affected bone segments, printed by 3D printer, and based on CT scans of the patients. The surgical implant was managed with dedicated instruments. The use of 3D technology can improve the results of orthopedic surgery in many ways: by optimizing the outcomes of the operation as it allows a preliminary study of the bone loss and an evalutation of feasibility of the surgery, it improves the precision of the positioning of the implant, especially in the context of severe deformity and bone loss, and it reduces the operating time; by improving surgeon training; by increasing patient involvement in decision making and informed consent. 3D technology, by offering targeted and customized solutions, is a valid tool to obtain the tailored care that every patient needs and deserves, also providing the surgeon with an important help in cases of great complexity

THA in patients with acetabular bone defects is associated with a high risk of dislocation. Dual mobility (DM) cups are known to prevent and treat chronic instability. The aim of this study was to evaluate the dislocation rate and survival of jumbo DM cups. This was a retrospective, continuous, multicenter study of all the cases of jumbo DM cup implantation between 2010 and 2017 in patients with acetabular bone loss (Paprosky 2A: 46%, 2B: 32%, 2C: 15% and 3A: 6%). The indications for implantation were revisions for aseptic loosening of the cup (n=45), aseptic loosening of the femoral stem (n=3), bipolar loosening (n=11), septic loosening (n=10), periprosthetic fracture (n=5), chronic dislocation (n=4), intraprosthetic dislocation (n=2), cup impingement (n=1), primary posttraumatic arthroplasty (n=8), and acetabular dysplasia (n=4). The jumbo cups used were COPTOS TH (SERF), which combines press-fit fixation with supplemental fixation (acetabular hook, two superior flanges with one to four screws, two acetabular pegs). A bone graft was added in 74 cases (80%). The clinical assessment consisted of the Harris hip score. The primary endpoint was surgical revision for aseptic acetabular loosening or the occurrence of a dislocation episode. In all, 93 patients were reviewed at a mean follow-up of 5.3 ± 2.3 years [0, 10]. As of the last follow-up, the acetabular cup had been changed in five cases: three due to aseptic loosening (3.2%) and two due to infection (2.1%). The survivorship free of aseptic loosening was 96.8%. Three patients (3%) suffered a dislocation. At the last follow-up visit, the mean HSS scores were 72.15, (p < 0.05). Use of a jumbo DM cup in cases of acetabular bone defects leads to satisfactory medium-term results with low dislocation and loosening rates

We present the indications and outcomes of a series of custom 3D printed titanium acetabular implants used over a 9 year period at our institution (Sydney, Australia), in the setting of revision total hip arthroplasty. Individualised image-based case planning with additive manufacturing of pelvic components was combined with screw fixation and off-the-shelf femoral components to treat patients presenting with failed hip arthroplasty involving acetabular bone loss. Retrospective chart review was performed on the practices of three contributing surgeons, with an initial search by item number of the Medicare Benefits Scheme linked to a case list maintained by the manufacturer. An analysis of indications, patient demographics and clinical outcome was performed. The cohort comprised 65.2% female with a median age of 70 years (interquartile range 61–77) and a median follow up of 32.9 months (IQR 13.1 - 49.7). The indications for surgery were infection (12.5%); aseptic loosening (78.1%) and fracture (9.4%), with 65.7% of cases undergoing previous revision hip arthroplasty. A tumour prosthesis was implanted into the proximal femur in 21.9% of cases. Complications were observed in 31.3% of cases, with four cases requiring revision procedures and no deaths reported in this series. Kaplan-Meier analysis of all-cause revision revealed an overall procedure survival of 88.7% at two years (95%confidence interval 69 - 96.2) and 83.8% (95%CI 62 - 93.7) at five years, with pelvic implant-specific survival of 98% (95%CI 86.6 - 99.7) at two and five year follow up. We conclude that an individualised planning approach for custom 3D printed titanium acetabular implants can provide high overall and implant-specific survival at up to five years follow up in complex cases of failed hip arthroplasty and acetabular bone loss