The radiological evaluation of the hip joint after prosthetic arthroplasty of the proximal femur in patients with a tumour using a bipolar femoral head

Artificial intelligence-based classification of bone tumors in the proximal femur on plain radiographs: System development and validation

Purpose

Early detection and classification of bone tumors in the proximal femur is crucial for their successful treatment. This study aimed to develop an artificial intelligence (AI) model to classify bone tumors in the proximal femur on plain radiographs.

Methods

Standard anteroposterior hip radiographs were obtained from a single tertiary referral center. A total of 538 femoral images were set for the AI model training, including 94 with malignant, 120 with benign, and 324 without tumors. The image data were pre-processed to be optimized for training of the deep learning model. The state-of-the-art convolutional neural network (CNN) algorithms were applied to pre-processed images to perform three-label classification (benign, malignant, or no tumor) on each femur. The performance of the CNN model was verified using fivefold cross-validation and was compared against that of four human doctors.

Results

The area under the receiver operating characteristic (AUROC) of the best performing CNN model for the three-label classification was 0.953 (95% confidence interval, 0.926–0.980). The diagnostic accuracy of the model (0.853) was significantly higher than that of the four doctors (0.794) (P = 0.001) and also that of each doctor individually (0.811, 0.796, 0.757, and 0.814, respectively) (P<0.05). The mean sensitivity, specificity, precision, and F1 score of the CNN models were 0.822, 0.912, 0.829, and 0.822, respectively, whereas the mean values of four doctors were 0.751, 0.889, 0.762, and 0.797, respectively.

Conclusions

The AI-based model demonstrated high performance in classifying the presence of bone tumors in the proximal femur on plain radiographs. Our findings suggest that AI-based technology can potentially reduce the misdiagnosis of doctors who are not specialists in musculoskeletal oncology.

Is bipolar hemiarthroplasty an appropriate type of hip articulation following proximal femoral or total femoral resections for musculoskeletal malignancies?

BACKGROUND

Different approaches are applied for reconstruction in patients with a musculoskeletal malignancy which require a proximal femoral or total femoral resection. We aimed to evaluate the treatment outcomes of patients who underwent a proximal femoral or total femoral resection due to bone and soft tissue tumors and had an endoprosthetic reconstruction by a bipolar hemiarthroplasty type of hip articulation.

METHODS

We retrospectively identified 133 patients who underwent a proximal femoral or total femoral endoprosthetic replacement after resection of a bone or soft tissue malignancy. There were 74 male and 59 female patients, with a mean age of 55.02 ± 16.92 years (range 11-84 years) and a median follow-up of 24.47 ± 24.45 months (range 6-164 months). Patient demographics, surgical, and oncological data were recorded. Acetabular wear was measured using the classification proposed by Baker. Functional assessment was performed using the Musculoskeletal Tumor Society (MSTS) functional score.

RESULTS

There was no statistically significant difference among primary diagnostic groups in terms of gender, prosthesis type, trochanter major resection, local recurrence, complication/revision rate, and MSTS Score (p > 0.05, for each parameter). On the other hand, a statistically significant difference was detected in terms of degree of acetabular erosion among diagnostic groups (p < 0.001); the acetabular erosion rate (AER) was found to be lower in patients with metastatic carcinoma than in patients with a diagnosis of primary bone or soft tissue sarcoma. The univariable analysis revealed that the effect of age, primary diagnosis, localization, follow-up time, and presence and number of distant organ metastasis variables on AER were found to be statistically significant (p = 0.018, p = 0.035, p = 0.002, p = 0.007, p = 0.031, p = 0.040, respectively).

CONCLUSION

In patients who undergo a proximal femoral or a total femoral resection due to a musculoskeletal tumor, bipolar hemiarthroplasty is an adequate type of hip articulation method, since it does not affect the revision requirements and functional outcomes of patients with acetabular erosion.

Long-term outcome of patients with primary or secondary tumors of the proximal femur treated by bipolar modular tumor prosthesis

PURPOSE

The proximal femur is a common area for primary and also metastatic bone tumors. The objective of this study was to assess the long-term functional and oncological outcomes of patients with malignant primary or secondary tumors of the proximal femur, who underwent proximal femoral resection then reconstruction using bipolar modular tumor prosthesis.

METHODS

Sixty patients with proximal femoral malignant tumors underwent resection and bipolar modular prosthesis between 2000 and 2016, were retrospectively reviewed. Based on diagnosis and presence or absence of pathological fracture, patients were divided into groups. The functional outcome of the patients was evaluated using the Musculoskeletal Tumor Society (MSTS) functional scoring system for the lower extremities.

RESULTS

The mean age was 38 (9-80) years at the time of primary surgery. Pathological fracture was the presentation in 28 patients. The study included 44 patients with primary bone tumor and 16 patients with a secondary bone tumor. The mean MSTS functional score of the patients was 24.3 (range, 18-30) points with no significant difference in patients with primary or secondary tumors. The rate of complications in the present series was 45%. The most frequent complication was an infection in 10 patients (16.7%), followed by aseptic loosening in 7 patients (11.7%). Local recurrence of primary bone tumors occurred in three out of 44 patients (6.8%).

CONCLUSION

Modular bipolar tumor prosthesis has a good long-term functional result in both primary and secondary tumors of the proximal femur, with no significant effect of age, presence or absence of pathological fracture or femoral resection length on the functional outcome. It was found that the only statistically significant variable regarding the risk of infection is previous surgeries.

LEVEL OF EVIDENCE

Level IV, retrospective case series.

Acetabular complications are the most common cause for revision surgery following proximal femoral endoprosthetic replacement : what is the best bearing option in the primary and revision setting?

AIMS

Proximal femoral endoprosthetic replacements (PFEPRs) are the most common reconstruction option for osseous defects following primary and metastatic tumour resection. This study aimed to compare the rate of implant failure between PFEPRs with monopolar and bipolar hemiarthroplasties and acetabular arthroplasties, and determine the optimum articulation for revision PFEPRs.

METHODS

This is a retrospective review of 233 patients who underwent PFEPR. The mean age was 54.7 years (SD 18.2), and 99 (42.5%) were male. There were 90 patients with primary bone tumours (38.6%), 122 with metastatic bone disease (52.4%), and 21 with haematological malignancy (9.0%). A total of 128 patients had monopolar (54.9%), 74 had bipolar hemiarthroplasty heads (31.8%), and 31 underwent acetabular arthroplasty (13.3%).

RESULTS

At a mean 74.4 months follow-up, the overall revision rate was 15.0%. Primary malignancy (p < 0.001) and age < 50 years (p < 0.001) were risk factors for revision. The risks of death and implant failure were similar in patients with primary disease (p = 0.872), but the risk of death was significantly greater for patients who had metastatic bone disease (p < 0.001). Acetabular-related implant failures comprised 74.3% of revisions; however, no difference between hemiarthroplasty or arthroplasty groups (p = 0.209), or between monopolar or bipolar hemiarthroplasties (p = 0.307), was observed. There was greater radiological wear in patients with longer follow-up and primary bone malignancy. Re-revision rates following a revision PFEPR was 34.3%, with dual-mobility bearings having the lowest rate of instability and re-revision (15.4%).

CONCLUSION

Hemiarthroplasty and arthroplasty PFEPRs carry the same risk of revision in the medium term, and is primarily due to acetabular complications. There is no difference in revision rates or erosion between monopolar and bipolar hemiarthroplasties. The main causes of failure were acetabular wear in the hemiarthroplasty group and instability in the arthroplasty group. These risks should be balanced and patient prognosis considered when contemplating the bearing choice. Dual-mobility, constrained bearings, or large diameter heads (> 32 mm) are recommended in all revision PFEPRs. Cite this article: Bone Joint J 2021;103-B(10):1633-1640.

Megaprosthesis Reconstruction of the Proximal Femur following Bone Tumour Resection: When Do We Need the Cup?

Purpose

Reconstruction of the proximal femur after tumour resection can be performed with proximal femoral endopros-theses (PFE). Many studies have reported that bipolar hemiarthroplasty (BHA) reduce the risk of dislocation after oncological resections. However, progressive cotyloiditis which might require acetabular resurfacing (total hip arthroplasty [THA]) has been reported. The aim of this study is to compare the results of BHA and THA after proximal femur resection.

Materials and Methods

A total of 104 consecutive patients affected by primary (n=52) and metastatic (n=52) bone tumours were included. Ninety patients underwent BHA and 14 patients underwent THA. Complications were recorded and classified according to the Henderson classification. At final follow-up, patients with the implant in site were functionally evaluated with modified Harris hip score (HHS).

Results

The mean follow-up was 50 months (range, 2–171 months). Twenty-four (23.1%) patients developed major complications. Eleven (12.2%) BHA required acetabular resurfacing. Patients affected by primary bone tumours showed an increased risk of THA conversion (P=0.042). A reduced risk was observed in patients younger than 35 years (P=0.043) and in those older than 65 years (P=0.033). Dislocation occurred in four case (3.8%), in particular after THA (P=0.021). At final follow-up, 93 patients had the prosthesis in site (80 BHA and 13 THA). Mean postoperative HHS was 70 (range, 30–90).

Conclusion

The risk of dislocation is lower for bipolar endoprosthesis compared to THA. However cotyloiditis and acetabular resurfacing might occurred.

Clinical outcomes of endoprosthetic reconstruction for proximal femoral resection

INTRODUCTION

The proximal femur is a common site for primary sarcomas and metastatic lesions. Although the early results of tumor prostheses are promising, the long-term results of reconstruction are unknown. The purpose of this study is to evaluate the prognostic factors affecting prosthesis survival and complications after proximal femoral resection and reconstruction.

METHODS

We reviewed the results of 68 patients who underwent proximal femoral resection and reconstruction with a modular bipolar-type tumor prosthesis between 2005 and 2017. The mean follow-up was 55.6 months (range 6-172 months). There were 50 male and 18 female patients with a mean age of 41.5 years (range 11-80 years). Cumulative survival analysis was performed to analyze the risk factors of prosthesis survival. We also evaluated the complications after operation.

RESULTS

Fourteen (21%) patients required further surgery at a mean 37 months post-operatively (range 5-125 months). There were three cases of infection (4%), six of local recurrence (9%), three of acetabular erosion (4%) and two of stem loosening (3%). The implant survival rates were 83.9% at 5 years and 59.8% at 10 years. Prosthesis survivals did not differ based on fixation method (P = 0.085), age (P = 0.329) or resection length (P = 0.61). Acetabular chondrolysis was identified in 18 (26%) patients and longer resection length (≥20 cm) showed a trend for risk of acetabular wear (P = 0.132).

CONCLUSION

The results of proximal femoral resection and reconstruction with a modular bipolar-type prosthesis were found to be acceptable with infection and local recurrence as short-term complications and loosening and acetabular erosion as long-term complications.

Survival and outcomes of modular endoprosthetic reconstruction of the proximal femur for primary and non-primary bone tumors: Single institutional results

Purpose

This study assessed implant survival and dislocation following proximal femur tumor endoprosthetic replacement.

Methods

Thirty-eight procedures were performed between 2005 and 2019. The cumulative incidence of implant revision was calculated with death as a competing risk.

Results

The majority of endoprostheses were bipolar hemiarthroplasty (n = 33, 86.8%). The cumulative incidence of revision was 14.6% (95% CI, 3.2%-34.1%) at five years. Dislocation occurred in 7.9% (n = 3) of hips at a mean (SD) 44 ± 35.2 days.

Conclusions

Proximal femur tumor endoprosthetic replacement is a durable option that tends to outlive patients. Strict postoperative bracing may lower dislocation rates.

Level of evidence

III. Retrospective Study.

Harrington rods for periacetabular pathological lesion: is it an option?

Advancement in cancer treatment has prolonged the survival of cancer patients; as a result, there are an increased number of patients with bone metastases and pathological fractures referred to orthopaedic surgeons for surgical intervention for a better quality of life. Metastasis around the hip joint can be painful and intervene with patients' daily activity, and reconstruction of the hip joint with periacetabular metastasis is complex and challenging especially longer cancer survivals might out-live their fixation. Several acetabular reconstruction techniques and implants have been described to overcome this problem; acetabular reconstruction and total hip arthroplasty still remains the standard surgical treatment, to relief pain and to improve function and quality of life. Harrington reconstruction of periacetabular metastatic disease combined with hip arthroplasty is one of the options that can address this clinical scenario safely; it is reproducible and cost-effective. In this review, we present case series of patients treated in our institution using Harrington rod technique for acetabular pathological lesions with good outcome.

Acetabular Erosion After Bipolar Hemiarthroplasty in Proximal Femoral Replacement for Malignant Bone Tumors

BACKGROUND

Hemiarthroplasty megaprosthetic proximal femur reconstruction after tumor resection is a widespread procedure in orthopedic oncology. One potential complication is acetabular wear requiring secondary acetabular revision. The study's purpose is to investigate prevalence of acetabular erosion, secondary revisions, and potential risk factors.

METHODS

We retrospectively identified 112 patients who underwent proximal femur replacement after resection of a malignant bone tumor and had radiological follow-up longer than 12 months. Patient demographic, surgical, and oncologic factors were recorded, acetabular wear was measured using the classification proposed by Baker, and prosthetic failure was classified using the International Society on Limb Salvage classification. Functional assessment was performed using the Musculoskeletal Tumor Society Score and Harris Hip Score.

RESULTS

Prevalence of acetabular wear was 28.6%. Secondary conversion to total hip arthroplasty was required in 5 patients (4.6%), all treated for primary bone tumors. No patient treated for metastatic tumor had higher grade acetabular wear or required revision. Significant risk factors for the development of acetabular wear were age under 40 (P = .035) and longer follow-up (63 vs 43 months, P = .004). Other patient, surgical, or adjuvant treatment-related factors were not associated with acetabular revision or acetabular wear. The dislocation rate in the patient cohort was 0.9%.

CONCLUSION

Bipolar hemiarthroplasty proximal femoral replacement represents a durable reconstruction after tumor resection. Hip instability is rare. Acetabular erosion is rare and can be successfully treated with conversion to total hip arthroplasty. Young patients with long-term survival over 10 years are at risk. In reconstruction for metastases, instability and acetabular wear are rare.

Advances in tumour endoprostheses: a systematic review

Tumour endoprostheses have facilitated limb-salvage procedures in primary bone and soft tissue sarcomas, and are increasingly being used in symptomatic metastases of the long bones.

The objective of the present review was to analyse articles published over the last three years on tumour endoprostheses and to summarize current knowledge on this topic. The NCBI PubMed webpage was used to identify original articles published between January 2015 and April 2018 in journals with an impact factor in the top 25.9% of the respective category (orthopaedics, multidisciplinary sciences).

The following search-terms were used: tumour endoprosthesis, advances tumour endoprosthesis, tumour megaprosthesis, prosthetic reconstruction AND tumour. We identified 347 original articles, of which 53 complied with the abovementioned criteria.

Articles were categorized into (1) tumour endoprostheses in the shoulder girdle, (2) tumour endoprostheses in the proximal femur, (3) tumour endoprostheses of the knee region, (4) tumour endoprostheses in the pelvis, (5) (expandable) prostheses in children and (6) long-term results of tumour endoprostheses.

The topics of interest covered by the selected studies largely matched with the main research questions stated at a consensus meeting, with survival outcome of orthopaedic implants being the most commonly raised research question.

As many studies reported on the risk of deep infections, research in the future should also focus on potential preventive methods in endoprosthetic tumour reconstruction.

Cite this article: EFORT Open Rev 2019;4:445-459. DOI: 10.1302/2058-5241.4.180081

How Often Do Acetabular Erosions Occur After Bipolar Hip Endoprostheses in Patients With Malignant Tumors and Are Erosions Associated With Outcomes Scores?

BACKGROUND

Bipolar endoprosthetic replacement is an option for reconstruction of the proximal femur to restore a functional extremity and salvage the limb. However, because these patients are young, there is a theoretical risk for long-term degenerative changes of the acetabulum. Currently, there is a paucity of data concerning the proportion of patients who experience degenerative acetabulum changes after reconstruction and whether these changes are associated with Musculoskeletal Tumor Society (MSTS) scores.

QUESTIONS/PURPOSES

(1) What proportion of patients develop acetabular cartilage degeneration after bipolar hemiarthroplasty for malignant tumor-related reconstructions? (2) What is the survivorship free from revision for acetabular wear, erosions, or progressive arthritis? (3) Is there an association between the presence of acetabular erosions and lower MSTS scores?

METHODS

Between 2000 and 2015, 148 patients underwent endoprosthetic reconstruction of the proximal femur with a bipolar hemiarthroplasty for a malignant tumor and were potentially eligible for this retrospective study. Minimum followup was 1 year except for those who died or were revised earlier; of the 148, no patients were lost to followup before that time who were not known to have died; mean followup on the remainder was 79 months (range, 12-220 months), and the mean time to death after surgery for those who died was 28 months (range, 0-196 months). Over the course of the study, 93 (63%) patients died. The mean (± SD) patient age was 57 ± 17 years, and 55% (81 of 148) of the patients were men. We used magnification-corrected supine AP plain radiographs of the hip to evaluate degenerative acetabulum changes, and we used the 1993 MSTS score to assess function through chart review and a longitudinally maintained institutional database. We used a competing-risks survivorship estimator rather than Kaplan-Meier because of the high proportion of patients who had died during the surveillance period.

RESULTS

Nineteen patients (13%) developed cartilage erosion > 2 mm in the acetabulum, with two also developing protrusio after proximal femoral replacement with a bipolar endoprosthesis. Three additional patients also developed signs of protrusio. The mean acetabular wear after bipolar replacement was 1.2 mm. Patients with longer followup (p = 0.001) were at higher risk for developing acetabular wear. Six patients underwent conversion to THA to treat hip pain. At 10 years the cumulative incidence for conversion to THA for acetabular wear is 5% (95% confidence interval [CI], 0%-11%), whereas the cumulative incidence of death was 70% (95% CI, 61%-79%). There was no difference in mean MSTS scores between patients who developed > 2 mm of acetabular erosion (65% ± 25%) and those who did not (67% ± 20%; p = 0.77).

CONCLUSIONS

Wear was uncommon among patients with malignant hip tumors treated with bipolar endoprostheses, but the followup here was short, and some patients indeed developed wear and underwent wear-related revisions to THA. Patients expected to survive more than a few years should have periodic radiographic surveillance and should be followed for a longer period to get a better sense for whether the problem worsens with time, as we expect it may, among patients who survive for longer periods.

LEVEL OF EVIDENCE

Level III, therapeutic study.

Hemiarthroplasty proximal femoral endoprostheses following tumour reconstruction: is acetabular replacement necessary?

AIMS

Dislocation rates are reportedly lower in patients requiring proximal femoral hemiarthroplasty than for patients undergoing hip arthroplasty for neoplasia. Without acetabular replacement, pain due to acetabular wear necessitating revision surgery has been described. We aimed to determine whether wear of the native acetabulum following hemiarthroplasty necessitates revision surgery with secondary replacement of the acetabulum after proximal femoral replacement (PFR) for tumour reconstruction.

PATIENTS AND METHODS

We reviewed 100 consecutive PFRs performed between January 2003 and January 2013 without acetabular resurfacing. The procedure was undertaken in 74 patients with metastases, for a primary bone tumour in 20 and for myeloma in six. There were 48 male and 52 female patients, with a mean age of 61.4 years (19 to 85) and median follow-up of two years (interquartile range (IQR) 0.5 to 3.7 years). In total, 52 patients presented with a pathological fracture and six presented with failed fixation of a previously instrumented pathological fracture.

RESULTS

All patients underwent reconstruction with either a unipolar (n = 64) or bipolar (n = 36) articulation. There were no dislocations and no acetabular resurfacings. Articular wear was graded using the criteria of Baker et al from 0 to 3, where by 0 is normal; grade 1 represents a narrowing of articular cartilage and no bone erosion; grade 2 represents acetabular bone erosion and early migration; and grade 3 represents protrusio acetabuli. Of the 49 patients with radiological follow-up greater than one year, six demonstrated grade 1 acetabular wear and two demonstrated grade 2 acetabular wear. The remainder demonstrated no radiographic evidence of wear. Median medial migration was 0.3 mm (IQR -0.2 to 0.7) and superior migration was 0.3 mm (IQR -0.2 to 0.6). No relationship between unipolar versus bipolar articulations and wear was evident.

CONCLUSION

Hemiarthroplasty PFRs for tumour reconstruction eliminate joint instability and, in the short to medium term, do not lead to native acetabular wear necessitating later acetabular resurfacing. Cite this article: Bone Joint J 2018;100B:101-8.

Durability of Hemiarthroplasty for Pathologic Proximal Femur Fractures

BACKGROUND

The hip is a common location for metastatic tumors. Due to the high loads placed through the proximal femur, surgery is often indicated to provide pain relief and restore function. Historically, these lesions are reconstructed with a hemiarthroplasty; however, there are few reports on the outcome of these reconstructions. The purpose of this study is to evaluate the outcome of hemiarthroplasty for the treatment of proximal femur metastatic disease, with a specific focus on the rates of conversion to total hip arthroplasty (THA).

METHODS

One hundred ninety-nine patients (102 women, 97 men) were treated using a hemiarthroplasty to reconstruct the proximal femur for metastatic disease between 1992 and 2014. Mean age and body mass index were 62 years and 27.4 kg/m², respectively. The most common site of primary disease was the breast (n = 63). The most common location for the metastatic disease was the femoral neck (n = 148). Mean follow-up for surviving patients was 4 years.

RESULTS

Over the course of the study, 2 (1%) patients underwent conversion to a THA due to groin pain and degenerative changes. In addition, complications occurred in 12% of patients, most commonly a deep venous thrombosis (n = 5). Following the procedure, mean Harris Hip Score and Musculoskeletal Tumor Society 1993 scores were 73 and 63%, respectively.

CONCLUSION

Reconstruction of the proximal femur with a hemiarthroplasty endoprosthesis provides a majority of patients with a durable means of reconstruction, with a low rate of conversion to THA.

The stability of the hip after the use of a proximal femoral endoprosthesis for oncological indications: analysis of variables relating to the patient and the surgical technique

AIMS

Instability of the hip is the most common mode of failure after reconstruction with a proximal femoral arthroplasty (PFA) using an endoprosthesis after excision of a tumour. Small studies report improved stability with capsular repair of the hip and other techniques, but these have not been investigated in a large series of patients. The aim of this study was to evaluate variables associated with the patient and the operation that affect post-operative stability. We hypothesised an association between capsular repair and stability.

PATIENTS AND METHODS

In a retrospective cohort study, we identified 527 adult patients who were treated with a PFA for tumours. Our data included demographics, the pathological diagnosis, the amount of resection of the abductor muscles, the techniques of reconstruction and the characteristics of the implant. We used regression analysis to compare patients with and without post-operative instability.

RESULTS

A total of 20 patients out of 527 (4%) had instability which presented at a mean of 35 days (3 to 131) post-operatively. Capsular repair was not associated with a reduced rate of instability. Bivariate analysis showed that a posterolateral surgical approach (odds ratio (OR) 0.11, 95% confidence interval (CI) 0.02 to 0.86) and the type of implant (p = 0.046) had a significant association with reduced instability; age > 60 years predicted instability (OR 3.17, 95% CI 1.00 to 9.98). Multivariate analysis showed age > 60 years (OR 5.09, 95% CI 1.23 to 21.07), female gender (OR 1.73, 95% CI 1.04 to 2.89), a malignant primary bone tumour (OR 2.04, 95% CI 1.06 to 3.95), and benign condition (OR 5.56, 95% CI 1.35 to 22.90), but not metastatic disease or soft-tissue tumours, predicted instability, while a posterolateral approach (OR 0.09, 95% CI 0.01 to 0.53) was protective against instability. No instability occurred when a synthetic graft was used in 70 patients.

CONCLUSION

Stability of the hip after PFA is influenced by variables associated with the patient, the pathology, the surgical technique and the implant. We did not find an association between capsular repair and improved stability. Extension of the tumour often dictates surgical technique; however, our results indicate that PFA using a posterolateral approach with a hemiarthroplasty and synthetic augment for soft-tissue repair confers the lowest risk of instability. Patients who are elderly, female, or with a primary benign or malignant bone tumour should be counselled about an increased risk of instability. Cite this article: Bone Joint J 2017;99-B:531-7.