Medial protrusio technique for placement of a porous-coated, hemispherical acetabular component without cement in a total hip arthroplasty in patients who have acetabular dysplasia

Is step-cut shortening osteotomy a better choice than transverse osteotomy for total hip arthroplasty for Crowe type III-IV hip dysplasia?

INTRODUCTION

Total hip arthroplasty for developmental hip dysplasia is a challenging surgery due to anatomic abnormalities. Crowe III and Crowe IV hip dysplasia generally necessitates a subtrochanteric shortening osteotomy. Transverse and step-cut osteotomy are the most common procedures for shortening of femur although there is still no consensus which one is a superior method. The objective of this study was to demonstrate whether transverse or step-cut osteotomy is superior in hips who undergo arthroplasty for high riding hip dysplasia.

HYPOTHESIS

Our hypothesis was that higher rates of union would be achieved in patients with Crowe III-IV hip dysplasia when the step-cut osteotomy was performed compared to transverse osteotomies.

MATERIAL AND METHODS

A total of 99 hips from 90 patients (9 bilateral, 81 unilateral; 79 female, 11 male), each with a minimum follow-up duration of two years, were included in this study. The hips were classified as Crowe III (n=16) or IV (n=83). All hips were implanted cementless. Transverse or step-cut osteotomy was chosen for osteotomy type. The clinical and functional outcomes were assessed using the Harris Hip Score (HHS), limb length discrepancy (LLD), and limping. The complications and management of these were noted. The union rates were compared between osteotomy types.

RESULTS

The mean age at surgery was 48.8 (range, 21-79 years). The follow-up period was 64.3 months in average (range, 24 to 192 months). The mean Harris Hip Score before surgery was 35.6 (range, 18-50), and increased to 88.1 (range, 61-98) points at the most recent follow-up. The preoperative leg length discrepancy (LLD) measured 5.3cm (with a range of 3 to 6.8), while the postoperative LLD reduced to 0.8cm (with a range of 0 to 1.6). There were a total of 38 complications in 35 patients out of 99 cases, resulting in a complication rate of 38.4%. The most frequent complication observed was intraoperative femoral fractures, occurring in 13 cases. Residual limping was seen in 73.7% of all. Step-cut osteotomy was performed in 64 hips (35 CDH stem [Zimmer Biomet, Warsaw, IN, USA], 29 Wagner Cone stem [Zimmer Biomet, Warsaw, IN, USA]) and, transverse in 35 hips (22 CDH, 13 Wagner Cone). Six hips had nonunion problem and all of them were operated with a step-cut osteotomy (z-score: -7.12 and p<0.00001, Mann-Whitney U Test).

CONCLUSION

Transverse osteotomy may be a better option while performing a shortening subtrochanteric level osteotomy for total hip arthroplasty for Crowe III-IV hips.

LEVEL OF EVIDENCE

Level III; observational retrospective cohort study.

Midterm Results of Severe Hip Dysplasia after Using a Cementless Acetabular Component with Bulk Bone Graft in Total Hip Arthroplasty: A Minimum Five-Year Follow-Up Study

In patients with severe hip dysplasia, total hip arthroplasty (THA) using bulk bone graft (BBG) enhances anatomic cup positioning and provides early structural support. This study assesses the mid-term outcomes of THA with BBG in patients with over 50% graft bone coverage. Among 1951 patients who underwent THA between 2003 and 2007, 183 had BBG. After excluding early dropouts and infections, 151 patients remained. They were classified into uncovered (<50% coverage, 79 patients) and covered (>50% coverage, 72 patients) groups. The efficacy of cup fixation was compared between these groups. After ten years, the survival rate for not needing THA revision was 98% in the uncovered group and 100% in the covered group, while the rate for radiographic stability was 93% versus 99%, respectively. Although the cutoff value for the uncovered portion could not be clarified in this study, the mid-term results for 50% to approximately 70% uncovered were comparable to those for 50% or lesser, which have previously been expected to perform well. Recently, biomechanically advantageous bone grafting techniques have been identified, and based on the results of this study, it may be possible to expand the indications for THA with bone grafting for developmental dysplasia of the hip.

A new classification to characterize and predict treatment of acetabular bone defects

BACKGROUND

The increasing amount of revision surgeries in total hip arthroplasty (THA) represents a burden for orthopedic surgeons given the complexity and unpredictability of this kind of surgery. The aim of the current study was to develop a new radiographic classification of acetabular bone defects stratify the severity of the lesion and to suggest the surgical strategy to address it.

METHODS

Radiographs of 151 consecutive patients who underwent acetabular revision surgery in our institution were collected to develop a new classification that groups the acetabular bone defects in three zones (A, B and C). The performance to predict treatment and inter- and intra-rater agreement were evaluated.

RESULTS

The ability of the newly proposed classification to predict treatment was 87.3% (k weighted: 0.65). The inter-rater reliability was 90.1% (k: 0.81), and the intra-rater reliability between the two sets of evaluations performed by the observer at 1-month distance was 97.5% (k: 0.94).

CONCLUSIONS

The newly proposed classification was able to characterize the extent of acetabular bone defects and predict pre-operatively the appropriate surgical treatment strategy in 87.3% of cases. It showed a strong agreement among raters and an almost perfect agreement among different measurements at 1 month distance. This new tool could be used in the preoperative assessment to drive the use of secondary level image examinations and the type of surgical management.

Total Hip Arthroplasty With Subtrochanteric Osteotomy for Crowe IV Dysplasia Using an Extensile Direct Anterior Approach: A Surgical Technique

The direct anterior approach (DAA) has been increasing in popularity for primary total hip arthroplasty (THA). Despite previously documented anatomic limitations to its direct distal extension, alternative exposure methods have been described to safely access the femoral diaphysis and facilitate increasingly complex primary and revision THA scenarios. The DAA has several purported advantages compared to alternative approaches (eg, posterior and lateral-based), including its muscle-sparing nature, use of an internervous plane, and preservation of posterior stabilizing structures. Proponents of the DAA cite decreased postoperative pain, quicker recovery times, potentially lower dislocation rates, ease of intraoperative fluoroscopy, and improved implant placement/restoration of leg lengths. The current literature, however, is sparse when considering the use of this approach in the setting of severely dysplastic hips necessitating a concurrent subtrochanteric shortening osteotomy. When utilizing a posterior approach in this population, previous work from Ollivier and colleagues demonstrated high rates of cementless implant osseointegration and significantly improved clinical outcomes at long-term follow-up. Although relatively few reports of addressing this pathology via the DAA currently exist, initial results are promising. This study seeks to provide a detailed description of a surgical technique for performing primary THA and ipsilateral subtrochanteric shortening osteotomy in this patient population utilizing an extensile DAA.

Medial Protrusio Technique Versus Structural Autologous Bone-Grafting Technique in Total Hip Arthroplasty for Crowe Type II to III Hip Dysplasia

BACKGROUND

It is unclear whether acetabular reconstruction techniques have any impact on clinical outcomes. This study aimed to determine (1) whether acetabular reconstruction techniques influenced the position of the acetabular cup and (2) whether clinical outcomes based on the acetabular reconstruction techniques differ in patients undergoing total hip arthroplasty (THA) with Crowe II to III developmental dysplasia of the hip.

METHODS

This was a retrospective analysis of prospectively collected data from 69 patients (74 hips) who were treated with cementless THA using medial protrusio technique (MPT) or structural autologous bone-grafting technique (SABT). There were 39 patients (41 hips) included in the MPT group and 30 patients (33 hips) in the SABT group. Clinical and radiographic outcomes were evaluated.

RESULTS

All patients were followed up for at least 3 years. There were similar results between the 2 groups in terms of blood loss, Harris hip score, leg length discrepancy, cup inclination, cup anteversion, and proportion of cup coverage (P > .05). The operative time was significantly longer in the SABT group compared with the MPT group (P < .001). The postoperative vertical center of rotation was significantly higher in the MPT group compared with the SABT group (P = .001), and postoperative horizontal center of rotation was significantly shallower in the SABT group compared with the MPT group (P < .001).

CONCLUSION

The MPT and SABT provide similar clinical and radiographic outcomes in the management of Crowe II to III developmental dysplasia of the hip by cementless THA. However, the MPT has the advantage of a shorter operative time, whereas the SABT is more conducive to placing the acetabular cup in an anatomic position.

LEVEL OF EVIDENCE

Level III, Therapeutic, Case-Control Study.

Comparative Study of Highly Cross-Linked Polyethylene Liner Wear by Hip Center Location Using Elevated Hip Center Technique in Crowe I to III Hip Dysplasia: Outcomes for a Minimum of Eighteen Years of Follow-Up

BACKGROUND

The literature has reported that supero-lateralization of the femoral head increases the rates of aseptic loosening and prosthesis revision. However, there are few reports on the influence of different hip center positions on liner wear with more than a 15-year follow-up period.

METHODS

From April 2000 to August 2003, 91 patients underwent 108 total hip arthroplasties using a highly cross-linked polyethylene liner combined with zirconia femoral head and cup components. Pelvic radiographs were used to assess the vertical and horizontal distances to the center of the hip and the amount of liner wear. Mean patient age at the time of surgery was 54 years (range, 33 to 73), and mean follow-up duration was 19 years (range, 18 to 21).

RESULTS

Average liner wear was 0.221 mm, with average annual wear of 0.012 mm/year. Mean vertical and horizontal distances for the hip center were 24.9 and 31.8 mm, respectively. There was no difference in linear wear between patients who had different hip center heights (<20, 20 to 30, and >30 mm), and quadrant partitioning showed no differences across the 4 quadrant zones.

CONCLUSION

At a minimum of 18 years of follow-up in patients having developmental dysplasia of the hip who had different Crowe subtypes and different hip centers, elevated hip center and uncemented fixation techniques using a highly cross-linked polyethylene on ceramic components were associated with very low wear rates and excellent functional scores.

The Validation of Two-Dimensional and Three-Dimensional Radiographic Measurements of Host Bone Coverage in Total Hip Arthroplasty for Hip Dysplasia: A Comparison with Intra-Operative Measurements

Several methods have been introduced to measure the host bone coverage of the acetabular component after total hip arthroplasty (THA). The aims of this study were (1) to validate two-dimensional- and three-dimensional-based host bone coverage measurements by comparing intra-operative measurements, and (2) to determine the minimum host bone coverage for achieving stable cup fixation after THA in hip dysplasia. The clinical outcomes of each patient were evaluated during their final follow-up period using the Harris Hip score (HHS). The coverage of the host bone was analyzed by comparing 2D-based, 3D-based, and intraoperative assessments. The mean HHS was increased significantly from 60.84 ± 14.21 pre-operatively to 93.13 ± 4.59 (p < 0.0001). The host bone coverage ratio measured intraoperatively was 83.67 ± 3.40%, while the ratio measured by 3D CT reconstruction was 82.72 ± 3.59%. There was a strong positive correlation between the intra-operative host bone coverage and the 3D-based one (r = 0.826, p < 0.0001). It is recommended that 3D-based measurements are used to evaluate the host bone coverage after THA in patients with hip dysplasia. In addition, achieving a minimum host bone coverage of 75% is recommended for the attainment of stable cup fixation.

The press-fit technique without screws and bone graft can be used as an alternative method in Crowe type II and III hip dysplasia

Background/aim

Developmental dysplasia of the hip (DDH) is the most common cause of secondary hip arthrosis. The primary purpose of this study was to assess the results of an oversized hemispherical cup via the press-fit technique used for Crowe type II and III DDH without screws and to determine if adequate medialization and initial stability of the acetabular component would allow us to avoid screw and graft use.

Materials and methods

Between February 2012 and May 2020, the current study analyzed 43 hips with Crowe type II and III DDH treated with a porous-coated cup by placing the press-fit technique or screw. The acetabular cup was fixed with the press-fit technique without additional screws in 27 hips and with screws in 16 hips. The inclusion criterion in this study was a minimum 2-year-period after the surgery.

Results

The mean duration of follow-up was 6.83 ± 2.67 years in the press-fit group and 6.21 ± 2.01 years in the screw group. The mean age of the patients was 47.96 ± 12.37 years in the press-fit group and 50.5 ± 12.37 years in the screw group. Measurements revealed that the hip center of rotation (HCR) was located more medially and superiorly postoperatively than preoperatively in both groups. The mean cup coverage in the screw group was 85.58% ± 7.51% (75.3%-97.2%), while it was less than 90.41% ± 6.15% (76.3%-98.2%) in the press-fit group (p = 0.038). No component was revised because of loosening, and all of the implants were radiologically stable within the observation period. No statistically significant differences were observed regarding the postoperative limp-length discrepancy between the groups (p = 0.496).

Conclusion

Press-fit implantation of a porous-coated acetabular component without screws can also be used as an alternative method for THA in Crowe type II and III DDH. The initial stability was obtained using the press-fit technique with a small cup positioned more medially and superiorly, which may allow the surgeon to avoid screw and graft use.

Total Hip Arthroplasty in Patients with Crowe III/IV Developmental Dysplasia of the Hip: Acetabular Morphology and Reconstruction Techniques

The severe anatomic deformities render acetabular reconstruction as one of the greatest challenges in total hip arthroplasty (THA) for patients with Crowe III/IV developmental dysplasia of the hip (DDH). Thorough understanding of acetabular morphology and bone defect is the basis of acetabular reconstruction techniques. Researchers have proposed either true acetabulum position reconstruction or high hip center (HHC) position reconstruction. The former can obtain the optimal hip biomechanics, including bulk femoral head autograft, acetabular medial wall displacement osteotomy, and acetabular component medialization, while the latter is relatively easy for hip reduction, as it can avoid neurovascular lesions and obtain more bone coverage; however, it cannot achieve good hip biomechanics. Both techniques have their own advantages and disadvantages. Although there is no consensus on which approach is better, most researchers suggest the true acetabulum position reconstruction. Based on the various acetabular deformities in DDH patients, evaluation of acetabular morphology, bone defect, and bone stock using the 3D image and acetabular component simulation techniques, as well as the soft tissue tension around the hip joint, individualized acetabular reconstruction plans can be formulated and appropriate techniques can be selected to acquire desired clinical outcomes.

Medial wall reconstruction using metal disc augments in revision total hip arthroplasty

PURPOSE

Medial acetabular bone defects are frequently encountered in revision total hip arthroplasty (THA), but few studies have focused on their reconstruction. This study aimed to report the radiographic and clinical results after medial acetabular wall reconstruction using metal disc augments in revision THA.

METHODS

Forty consecutive revision THA cases using metal disc augments for medial acetabular wall reconstruction were identified. Post-operative cup orientation, the centre of rotation (COR), stability of acetabular components and peri-augments osseointegration were measured. The pre-operative and post-operative Harris Hip Score (HHS) and Western Ontario and McMaster Universities Arthritis Index (WOMAC) were compared.

RESULTS

The mean post-operative inclination and anteversion were 41.88 ± 6.70° and 16.73 ± 5.35°, respectively. The median vertical and lateral distance between the reconstructed CORs and the anatomic CORs were -3.45 mm (interquartile range [IQR]: -11.30 mm, -0.02 mm) and 3.18 mm (IQR: -0.03 mm, 6.99 mm). Thirty-eight cases completed the minimum two year clinical follow-up, whereas 31 had a minimum two year radiographic follow-up. Acetabular components were radiographically stable with bone ingrowth in 30 cases (30/31, 96.8%) while one case was classified as radiographic failure. Osseointegration around disc augments was observed in 25 of 31 cases (80.6%). The median HHS improved from 33.50 (IQR: 27.50-40.25) pre-operatively to 90.00 (IQR: 86.50-96.25) (p < 0.001), whereas the median WOMAC significantly improved from 38.02 (IQR: 29.17-46.09) to 85.94 (IQR: 79.43-93.75) (p < 0.001).

CONCLUSION

In revision THA with severe medial acetabular bone defect, disc augments could provide favorable cup position and stability, peri-augments osseointegration, with satisfactory clinical scores.

Revision of a Failed Primary Total Hip Arthroplasty following Excessive Reaming with a Medial Cup Protrusion

Background and Objectives: Atraumatic intrapelvic protrusion of the acetabular component following excessive reaming of the acetabulum with a far medial positioning of the cup is a rare, but serious complication of a total hip arthroplasty (THA). This study analyzes the factors contributing to this uncommon complication and presents the outcome after the revision surgery using the Ganz reinforcement ring combined with a bone graft and plating of the posterior column and/or screws for the anterior column. Materials and Methods: A retrospective case series study with seven patients (four males, mean age 76 ± 10 years (60−86)) that underwent a revision THA within 24 ± 17 days (5−60) after an atraumatic periprosthetic acetabular fracture with a medial cup protrusion was performed. All fractures were reconstructed with a Ganz reinforcement ring and bone graft with a mean follow-up of 1.7 ± 1.7 years (0.5−5). Radiographs were evaluated for the following: (i) cup positioning immediately after the primary THA and the revision surgery, (ii) cup migration in the follow-up, and (iii) fracture healing. Results: The position of the acetabular component as assessed on the postoperative radiographs after the index surgery and before the complete medial cup protrusion showed a cup placement beyond the ilioischial line indicative of a fracture of the medial wall. The revision surgery with the reconstruction of the medial wall with a Ganz reinforcement ring combined with a bone graft restored in the presented cases the center of rotation in the horizontal direction with a statistical significance (p < 0.05). During the follow-up, there was no aseptic loosening with the relevant cup migration or significant change in the position of the acetabular cup at the final follow-up (p > 0.05) after the revision. All seven fractures and bone grafts realized a bone union until the latest follow-up. Conclusions: Following excessive reaming, the acetabular component was placed too far medially and resulted in an intrapelvic cup protrusion. An unstable cup following a fracture of the medial wall was evident on the immediate postoperative radiographs. In the case of the medial wall perforation with an intrapelvic cup protrusion after the primary THA, the reconstruction with a Ganz reinforcement ring was a successful treatment option resulting in the fracture healing and a stable cup positioning. Surgeons should be aware of that rare and probably underreported complication and restore the anatomic center of rotation by treating the defect intraoperatively.

Anatomic acetabular reconstruction with femoral head autograft for developmental dysplasia of the hip (DDH) with a minimum follow-up of 10 years

BACKGROUND

DDH with coxarthrosis causes significant deformity and bone deficiency. Various reconstructive techniques have been proposed to treat developmental dysplasia of the hip. However, the existing literature has not yet reached a consensus on the best technique regarding long-term survival.

OBJECTIVES

This study aims to evaluate the long-term survival of uncemented hydroxyapatite (HA) coated acetabular components augmented with a femoral head autograft.

METHODS

We retrospectively reviewed the cases of 31 hips in 29 patients (24 female, 5 male, mean age 45.06 years) treated with HA-coated cementless components and femoral head autograft between 2000-2008 with a minimum follow-up of 10 years. Graft resorption, cup loosening and the anatomical hip centre were determined. Functional outcomes were calculated using the Harris Hip Scoring system. The survival of the acetabular component was evaluated using the Kaplan-Meier method.

RESULTS

In 24 hips (77,4%), we reconstructed the hip centre anatomically. The remaining cups had variable deviations from the anatomical rotation centre. Only one patient required revision due to loosening. Survival analysis revealed 96.8% survival at 10 years. The mean Harris Hip Score was 39.23 preoperatively and 84.77 at final follow-up. There was no statistical correlation between revision and any of the measured parameters.

DISCUSSION

Acetabular reconstruction with a femoral head autograft allows for anatomical cup positioning, early structural support and increases bone stock for future revisions. Although our prior cemented cup study showed that anatomical cup orientation is critical, this study demonstrated the absence of a correlation between implant failure and cup positioning, suggesting that HA-coated cementless cups are more stable and forgiving.

CONCLUSIONS

HA-coated acetabular cups augmented with femoral head autograft provided long-term, reliable and durable cup fixation in dysplastic hips of young adults.

Intraoperative two-stage evaluation of muscle contractures in Crowe type IV hips in total hip arthroplasty (a new surgical technique)

BACKGROUND

It is important to maintain soft-tissue balance and prevent muscle contractures after hip reduction during total hip arthroplasty (THA) in patients with Crowe type IV developmental dysplasia of the hip (DDH). To make such hips functional and durable, the techniques to achieve soft-tissue balance were studied to create an algorithm for intraoperative 2-stage evaluation of muscle contractures, specifying the optimal order for contracture release.

METHODS

Between February 2011 and March 2015, we evaluated 64 patients (75 hips) with DDH for muscle contractures as they underwent THA. Following acetabular implantation, femoral osteotomy was applied of various lengths according to limb-length discrepancy. First, the distal part of the femur was prepared by broaching, and the hip was then reduced. The tensor fascia lata, rectus femoris, sartorius, hamstrings, and adductor muscles were evaluated, and any contractures were released. A trial conjoining of the distal and proximal parts of the femur was made, and the hip was reduced again. Finally, the iliopsoas and abductor muscles were evaluated, and contractures were released.

RESULTS

The mean follow-up duration was 4.6 years. Preoperative and postoperative Harris Hip Scores were 52 and 87, respectively. Limb-length discrepancy was mean 4.2 cm preoperatively, and <1 cm postoperatively. All contractures were released according to our newly developed algorithm.

CONCLUSIONS

It is challenging to pinpoint the main muscle causing contractures, because other muscles acting on the hip joint have similar secondary functions. The method we describe here may provide better and more specific restoration of muscle function in a hypoplastic hemipelvis in DDH.

Femoral Head Autograft Can Reliably Reconstruct Dysplastic Acetabula Through the Direct Anterior Approach for Total Hip Arthroplasty

Background

Bone deficiencies in dysplastic acetabula create technical difficulties during total hip arthroplasty (THA). Bulk femoral head autograft (FHA) is one method to increase cup coverage and bone stock of the true acetabulum; however, only limited data exist on its efficacy through a direct anterior approach (DAA). This study aimed to evaluate the outcomes of FHA during THA via a DAA in dysplastic hips.

Methods

Retrospective review of 34 patients (41 hips) with hip dysplasia (Crowe I-III) who underwent primary THA via a DAA with FHA at a single institution was performed. Surgical procedures were performed on a traction table with intraoperative fluoroscopy and highly porous-coated cup placement in the true acetabulum. Patients were assessed clinically and radiographically at a minimum of 2 years postoperatively (range, 2 to 7).

Results

The average modified Harris Hip Score improved from 31.9 ± 10.8 to 94.1 ± 5.8, Merle d'Aubigné Hip Score from 7.5 ± 2.8 to 16.6 ± 1.1, and visual analog pain score from 7.9 ± 2.7 to 1.4 ± 1.4 (all P < .001). All hips had an “anatomic” inferomedial cup position postoperatively, with an average increase in horizontal coverage of 43.4%. Mean postoperative limb-length discrepancy improved from 21.8 ± 16.1 mm to 1.6 ± 5.7 mm (P < .001). There were no cases of revision THA, nor complications such as dislocation, infection, or osteolysis.

Conclusion

Reconstructing dysplastic acetabula (Crowe I-III) with FHA during THA can be successfully accomplished via the DAA with increased acetabular bone stock and accurate correction of limb-length discrepancy.

Developmental Hip Dysplasia Treated with Cementless Total Hip Arthroplasty Using a Straight Stem and a Threaded Cup-A Concise Follow-Up, At a Mean of Twenty-Three Years

We previously reported the 9-year follow-up results of 121 cementless total hip arthroplasties (THAs) from 1990 to 1994 in 93 patients with developmental dysplasia of the hip (DDH). The present study reports the updated long-term results after a mean follow-up of 23 years. Fifty-seven patients (72 hips) were alive and available for follow-up. Since our previous report, nine THAs had been revised. The cumulative implant survivorship of any component was 87% (95% CI, 78–92%). The cumulative probability of not having aseptic cup loosening was 87% (95% CI, 77–93%) and there was no revision surgery for aseptic stem loosening. In three hips (5%), an exchange of the ball and liner due to polyethylene wear was performed after a mean of 12 years. This study demonstrates that cementless THA for DDH with restoration of the hip joint center provides excellent long-term durability.

Anterior Total Hip Arthroplasty With Bulk Femoral Head Autograft in a Patient With Camurati-Engelmann Disease

Camurati-Engelmann disease (CED) is an extremely rare, sclerosing bone disorder of intramedullary ossification with only 300 reported cases worldwide. The pathogenesis is related to activating mutations in transforming growth factor beta 1, which results in bilateral, symmetric hyperostosis affecting primarily the diaphysis of long bones. Despite effective pharmacological treatment options, the diagnosis of CED is problematic owning to its rarity and variability of clinical presentation. We present a patient with known CED with advanced early hip osteoarthritis, secondary to underlying hip dysplasia, for which she underwent a successful total hip arthroplasty via a direct anterior approach with the use of bulk femoral head autograft to reconstruct her native acetabulum.

The fate of femoral head autograft in acetabular reconstruction in dysplastic hips at midterm

PURPOSE

To evaluate the acetabular cup and graft survival in patients who underwent total hip arthroplasty (THA) with the diagnosis of dysplastic hip osteoarthritis and received a femoral head autograft due to acetabular coverage deficiency.

METHODS

Between January 2005 and December 2016, 83 hip prostheses of 80 patients who underwent THA using femoral head autografts and were followed up for at least 2 years were retrospectively evaluated. Seventy-four hips of the remaining 71 patients (57 female (80%)) were included. Mean patient age at surgery was 51 ± 16 (range 18-76) years. The mean follow-up duration was 76 ± 25 (range 25-161) months. Acetabular inclination and graft thickness, contact length, percentage of coverage, and graft resorption were examined on postoperative and final follow-up radiographs. The presence of a radiolucent area around the acetabular and femoral components indicating loosening was also evaluated.

RESULTS

The mean postoperative acetabular component inclination was 44 ± 5.1° (range 30-48°) with mean graft coverage of 34 ± 4.8% (range 24-46%). In all patients, autograft union with the pelvis was seen and the lateral overflow was remodeled. Fifteen patients (20%) underwent revision surgery due to aseptic acetabular component loosening in four, nontraumatic recurrent dislocations in eight, periprosthetic infection in one, acetabular component protrusion in one, and traumatic hip dislocation in one.

CONCLUSION

In patients with osteoarthritis secondary to developmental hip dysplasia, the use of femoral head autografts to eliminate acetabular coverage deficiency during THA achieves acceptable midterm postoperative radiological outcomes. Increased acetabular bone stock may be beneficial in possible future revision surgeries.

Controlled fracture of the medial wall versus structural autograft with bulk femoral head to increase cup coverage by host bone for total hip arthroplasty in osteoarthritis secondary to developmental dysplasia of the hip: a retrospective cohort study

Background

Many methods have been proposed to increase cup coverage by host bone during primary total hip arthroplasty (THA) in hip osteoarthritis secondary to developmental dysplasia of the hip (DDH). However, there was no study comparing the results of controlled fracture of the medial wall with a structural autograft with a bulk femoral head.

Methods

Sixty-seven hips classified as Crowe II/III were retrospectively included in this cohort study, which consisted of 33 controlled fractures (group A) and 34 structural autografts (group B). The Harris Hip Scores (HHS) were recorded. The radiological assessments were analyzed. Also, complications are assessed. The paired-sample t test was used for data analysis before and after the operation, while the independent sample T test was used for the comparison between the two groups. The Pearson chi-square test or the Fisher exact test was used to analyze the qualitative comparative parameters. Kaplan-Meier was utilized in the analysis of survivorship with the end points as a revision for any component.

Results

All patients were reconstructed acetabulum at the anatomical location. HHS increased greatly for both groups (p = 0.18). No statistic difference was observed for the two groups in postoperative leg-length discrepancy (0.51 ± 0.29 cm for group A and 0.46 ± 0.39 cm for group B, p = 0.64 ), postoperative height of the hip center (2.25 ± 0.42 cm for group A and 2.09 ± 0.31 cm for group B, p = 0.13), and inclination of the cup (39 ± 4° for group A and 38 ± 3° for group B, p = 0.65 ). The rate of cup coverage for group B (94 ± 2%) was better than for group A (91 ± 5%), (p = .009). The rate of cup protrusio was 48 ± 4% for group A. For both groups, no statistical difference was observed in the cup diameter (p > .05), while group A showed less operation time than group B (p < .001). No complications were observed at the latest follow-up.

Conclusion

Controlled fracture of the medial wall to increase cup coverage by host bone at the anatomical location can act as an alternative technique for DDH Crowe II/III with the advantage of shorter operation time and less technically demanding.

Surgical Technique and Case Series of Total Hip Arthroplasty with the Hueter Anterior Approach for Crowe Type-IV Dysplasia

BACKGROUND

Total hip arthroplasty (THA) is being increasingly performed via the Hueter anterior approach (HAA), which has proven benefits with nondysplastic hips; however, little has been published on its outcomes with dysplastic hips, where it can provide better acetabular exposure. We describe our technique for THA via the HAA in hips with Crowe type-IV developmental dysplasia and report the mid-term outcomes of cases that were performed over 5 consecutive years.

METHODS

We retrospectively evaluated a continuous series of 8 hips (6 patients) with Crowe type-IV dysplasia; the patient ages ranged from 44 ± 20 years (range, 17 to 65 years) at the index THA. All of the patients received uncemented implants via the HAA on a traction table to restore the hip center of rotation to the true acetabulum. Femoral head autografts (FHAs) were used to increase acetabular coverage in 6 hips, and subtrochanteric shortening osteotomies (SSOs) were performed in 5 hips. Patients were assessed clinically and radiographically at a minimum follow-up of 2 years.

RESULTS

There were no revisions, deaths, dislocations, or infections. Two hips (25%) had intraoperative complications, and 1 hip (13%) had a postoperative complication that required reoperation without implant removal. All of the hips were assessed clinically and radiographically at 4 ± 1 years (range, 2 to 6 years). The modified Harris hip score (mHHS) improved from 33 ± 7 to 90 ± 7, and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) improved from 53 ± 14 to 89 ± 6; the postoperative leg-length discrepancy was 3.2 mm (range, -10 to 20 mm). None of the hips had osteolysis or radiolucent lines of >2 mm.

CONCLUSIONS

THA via the HAA on a traction table for hips with Crowe type-IV dysplasia yielded satisfactory mid-term outcomes. Both FHA and SSO can be adequately performed via the HAA to help restore the hip center of rotation to the true acetabulum.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Stepped osteotomy of femoral head autograft for acetabular reconstruction in total hip arthroplasty for dysplasia of the hip: 3 to 12 years' results

OBJECTIVES

This study aims to describe a stepped osteotomy technique applied to the femoral head autograft to keep the graft volume at a sufficient level, provide primary stability, and direct cancellous-cancellous bone contact.

PATIENTS AND METHODS

In this retrospective study, 24 hips of 20 patients (5 males, 15 females; mean age 53 years; range, 43 to 68 years) with dysplasia of the hip (DDH) who underwent total hip arthroplasty with femoral head stepped osteotomy technique were evaluated between April 2003 and June 2010. Patients' age, gender, operation side, and postoperative complications were recorded. Aseptic loosening of the acetabular cup and graft integration/resorption were evaluated radiographically. Radiological evaluations were performed according to the methods of DeLee and Charnley, and Mulroy and Harris. Functional status of the patients was determined according to the criteria of Merle d'Aubigné and Postel, and Harris hip score (HHS).

RESULTS

The mean follow-up period was 5.5 years (range, 3 to 12 years). None of the patients had any complications in the early postoperative period. In all patients, the percentage of acetabular component coverage by the graft was measured as 27% (range, 19 to 38%) on average. At the last follow-up, all patients were satisfied with the result and there was no sign of clinically loosening, osteointegration was complete, and there was no radiographic evidence of graft resorption or collapse of any hip. The overall Merle d'Aubigné scores and HHSs of the patients significantly improved at the final follow-up.

CONCLUSION

This stepped osteotomy technique increases the probability of osteointegration, reduces the need for early revision, and provides reliable stability with satisfactory clinical and radiological midterm results.

The Direct Anterior Approach for Total Hip Arthroplasty for Severe Dysplasia (Crowe III and IV) Provides Satisfactory Medium to Long-Term Outcomes

BACKGROUND

The direct anterior approach (DAA) is increasingly used for total hip arthroplasty (THA). Although the DAA can reduce pain, recovery time, and dislocations in nondysplastic hips, few studies report its results in patients with severe dysplasia. We aimed to evaluate outcomes of primary THA through the DAA with cup placement at the true acetabulum in hips with severe dysplasia.

METHODS

We retrospectively evaluated 23 consecutive patients (29 hips) who underwent THA by DAA for osteoarthritis secondary to Crowe III-IV dysplasia. Surgical procedures were performed on a traction table, and the acetabular cup was placed in the true acetabulum. Patients were assessed clinically (complications, modified Harris Hip Score, Western Ontario and McMaster Universities Osteoarthritis Index, Oxford Hip Score) and radiographically (radiolucencies, subsidence, leg length discrepancies, cup inclination, and cup coverage) at a minimum of 2 years.

RESULTS

One patient (2 hips) died with original implants (at 13 and 14 years), 3 patients (3 hips) were revised due to wear-induced loosening (at 14, 16, and 18 years), and there were no dislocations or infections. The remaining 19 patients (24 hips) were assessed at 8.4 ± 4.7 years (range 2-20); 2 patients (2 hips) had complications that required reoperation without implant removal. The modified Harris Hip Score improved from 32 ± 9 to 94 ± 7, Western Ontario and McMaster Universities Osteoarthritis Index from 46 ± 18 to 90 ± 7, and Oxford Hip Score was 56 ± 4. Patients were very satisfied (90%) or satisfied (10%). Limb length discrepancy was 2.5 ± 9.0 mm.

CONCLUSION

THA through the DAA with cup placement at the true acetabulum provides satisfactory mid to long-term clinical and radiographic outcomes compared to other approaches for hips with severe dysplasia.

LEVEL OF EVIDENCE

Level IV, retrospective cohort study.

Segmental uncoverage ratio analysis of Crowe type-IV developmental dysplasia of the hip via 3-dimensional implantation simulation

BACKGROUND

To study the segmental uncoverage ratio (UCR) of a 44-mm cup model placed in a true acetabulum of Crowe type-IV developmental dysplasia of the hip via 3-Dimensional (3D) implantation simulation.

METHODS

Qualified CT imaging data of 26 patients (involving 30 hips) with Crowe type-IV DDH were imported into Mimics software for reconstruction. Then a 44-mm eggshell cup model was placed in a true acetabulum. First, total uncoverage ratio (TUCR) was measured. Then the virtual cup was divided into 4 segments according to the quadrant setting of the true acetabulum, i.e., anterior-superior (A-S) segment, anterior-inferior (A-I) segment, posterior-superior (P-S) segment and posterior-inferior (P-I) segment. The UCRs of the aforementioned segments were measured, i.e., anterior-superior uncoverage ratio (A-SUCR), anterior-inferior uncoverage ratio (A-IUCR), posterior-superior uncoverage ratio (P-SUCR) and posterior-inferior uncoverage ratio (P-IUCR). The acetabular height and anterior-posterior diameter on the 3-D model were also calculated. Statistic analyses were performed by using SPSS software package.

RESULTS

TUCR was 0.2958 ± 0.1003 (95% [CI], 0.1020 to 0.5400) in this cohort of Crowe Type-IV hips. P-SUCR had the greatest value among all the segmental UCRs (0.1012 ± 0.0435, 95% confidence interval [CI],0.0152 to 0.1914) and the most significant positive correlation with TUCR (Pearson correlation = 0.889, p < 0.01. Linear regression R² = 0.791). Similarly, P-IUCR and A-SUCR showed a significant positive correlation with TUCR. However, A-IUCR exhibited no correlation with either total or other segmental UCRs. P-SUCR was found to bear significant positive correlation with P-IUCR (pearson correlation = 0.644, p < 0.01. Linear regression R² = 0.415). Acetabular height and A-P diameter were not correlated with TUCR.

CONCLUSION

Implantation of a 44-mm cup into Crowe type IV acetabulum is feasible and could achieve acceptable host bone coverage in most of the cases. P-SUCR contributed most to TUCR. TUCR had no linear relationship with the size of the host acetabulum, suggesting that the pre-operative plan should be individualized.

Use of ceramic-on-ceramic bearing in total hip arthroplasty for posttraumatic arthritis of the hip

PURPOSE

We aimed to evaluate (1) the intraoperative parameters, (2) cup position, (3) complications, (4) long-term results, and (5) the survivorship of cementless total hip arthroplastys (THAs) with use of ceramic bearings in patients with a history of acetabular fracture.

METHODS

We compared 57 THAs in patients, who were treated due to previous acetabular fracture (posttraumatic group), with 57 propensity score-matched THAs in patients, who were operated due to femoral head osteonecrosis (osteonecrotic group), at a minimum of 5-year follow-up.

RESULTS

The operation time was longer ( p = 0.008), and the volume of transfusion was larger ( p = 0.0.23) in the posttraumatic group. The cup abduction (39.4° ± 6.0° vs. 39.7°±4.8°) and anteversion (24.7° ± 8.0° vs. 26.7°±7.7°) were similar between the two groups. There was one dislocation in the posttraumatic group. There was no ceramic fracture in either group. One posttraumatic patient underwent excision of exuberant heterotrophic ossification at 3 years after the arthroplasty. The mean University of California, Los Angeles activity improved from 3.6 to 4.9 points in the posttraumatic group and 3.5 to 5.2 points in the osteonecrotic group. All acetabular cups and femoral stems had bone-ingrown stability. When reoperation for any reason was used as the end point, the 10-year survival rate was 98.3% (95% CI: 95.0-100) in the posttraumatic group and 100% in the osteonecrotic group.

CONCLUSION

In our study, posttraumatic patients had longer operation time and larger volume of transfusion than osteonecrotic patients. However, medium-term results and survivorship were similar with those of osteonecrotic patients.

Current concepts in developmental dysplasia of the hip and Total hip arthroplasty

Developmental dysplasia of the hip (DDH) is a spectrum of pathology that involves dysplasia of both the acetabulum and the femur. If left untreated, it can develop to hip pain and osteoarthritis, which eventually require total hip arthroplasty (THA). A broad array of anatomical abnormalities of the acetabulum and femur, plus the younger age of DDH patients make THA a great challenge. Meticulous operation planning with various options is one of the most important prerequisites of a successful THA. This review presents the current concepts of acetabular and femoral reconstruction in THA for DDH, including high hip center, acetabular bone deficiency, highly porous metal, correction of femoral anteversion, femoral shortening osteotomy, stem selection, among others.

Primary Total Hip Arthroplasty in Severe Dysplastic Hip Osteoarthritis With a Far Proximal Cup Position

BACKGROUND

Developmental hip dysplasia is the most common cause of secondary hip osteoarthritis. Due to severe acetabular bone deficiency, cup positioning in total hip arthroplasty (THA) of dysplastic hips remains a surgical challenge. The aim was to analyze the functional outcome of far proximal cup positions in primary THA.

METHODS

Fifty patients (61 hips) with THA for severe dysplastic osteoarthritis and a far proximal cup position were included. Patients were divided according to the heights of the implanted cups with increasing vertical distance from the interteardrop line (group A: 55-65 mm, group B: 65-75 mm, group C: >75 mm). Functional outcome was assessed at latest follow-up (38 ± 16 months) by Lower Extremity Functional Score, Tegner Activity Score, and Harris Hip Score (HHS). Patients answered a Patient Satisfaction Questionnaire. Leg length discrepancy was estimated radiographically.

RESULTS

The Lower Extremity Functional Score significantly decreased in C (45.3 ± 25) compared to A (66.7 ± 15.3) and B (67.9 ± 9.9). The Tegner Activity Score significantly increased in all subgroups from preoperative to postoperative (2.2 ± 1.3 to 4.1 ± 1.4; P < .05). The mean overall HHS was 89.3 ± 14.7 (A: 89.5 ± 14.3, B: 94.3 ± 6.5, C: 78.3 ± 22.1). The HHS domains of activity of daily life and gait were significantly reduced in C (P < .05). Patients described a high satisfaction level with the surgery. No significant differences were found with regard to preoperative and postoperative leg lengthening (P = .881). Neither dislocations, impingement problems nor neurologic complications were observed.

CONCLUSION

Primary THA without any concomitant surgical interventions with a far proximal cup position offers a safe and effective treatment option in severe dysplastic hip osteoarthritis.

How does anteroposterior cup placement affect bone coverage and range of motion in primary total hip arthroplasty for hip dysplasia?

BACKGROUND

Due to anterior bone defects, high and/or posterior placement of an acetabular cup is often required to achieve sufficient coverage in patients with hip dysplasia. We examined whether posterior cup placement affected the postoperative range of motion (ROM) in primary total hip arthroplasty (THA).

METHODS

Using computer software, bone coverage and ROM were examined in 32 patients with unilateral osteoarthritis of the hip with Crowe type II or III hip dysplasia. We determined the cup position to satisfy cup center-edge (Cup-CE) angle ≥0° and the required ROM. The cup was placed at the anatomic hip center and moved in 2-mm increments anteroposteriorly and 10-mm increments vertically.

RESULTS

At vertical anatomic hip center, less than 68.8% hips fulfilled Cup-CE ≥0° regardless of anteroposterior position. Significantly more hips at higher hip center with posterior cup placement achieved Cup-CE ≥0° than hips at vertical anatomic hip center, and 10 mm higher hip center was the most suitable for achieving bone coverage. However, posterior and superior cup placement significantly decreased the flexion and IR due to early bone impingement, whereas ER and extension were not affected. A smoothing spline curve demonstrated that more posterior cup placement than 4.8 mm and 3.6 mm did not satisfy the required ROM at 10 mm and 20 mm higher hip center, respectively.

CONCLUSIONS

Posterosuperior cup placement gained more bone coverage but decreased the range of hip flexion and internal rotation. Consequently, posterosuperior cup placement did not satisfy the required ROM.

Three-Dimensional Host Bone Coverage Required in Total Hip Arthroplasty for Developmental Dysplasia of the Hip and Its Relationship With 2-Dimensional Coverage

BACKGROUND

In total hip arthroplasty, the minimum host bone coverage required on the cup for stable fixation has been previously reported; however, the coverage was generally evaluated on a 2-dimensional (2D) image and 3-dimensional (3D) coverage has not been well described.

METHODS

We used postoperative computed tomography images to retrospectively measure 3D cup coverage in 151 hips with developmental dysplasia of the hip that underwent primary total hip arthroplasty. The aims were to (1) determine the minimum requirement of the 3D coverage for stable cup fixation; (2) evaluate the relationship between 2D and 3D coverage; and (3) identify the factors associated with 2D-3D discrepancy, defined as follows: 2D-3D discrepancy = 2D coverage-3D coverage.

RESULTS

All cups showed stable fixation as demonstrated by bone ingrowth with an average postoperative period of 48 months. The minimum 3D coverage was 61.2%, with a mean value of 77.1% ± 6.7% and maximum value of 97.6%. We found a significant positive but poor relationship between 3D and 2D coverage (bone coverage index; r = 0.30). Consequently, the 2D-3D discrepancy varied greatly, with a mean value of -1.6% ± 12.3% (range, -36.5% to 32.2%). Multiple linear regression analyses confirmed that lower cup center and anterior tilt of the pelvis relative to the computed tomography table were independent factors associated with increasing 2D-3D discrepancy.

CONCLUSION

This study showed that 2D coverage, measured on a projected image, carries a risk of overestimation, especially in hips with the aforementioned features.

Polyethylene Hip Resurfacing to Treat Arthritis and Severe Acetabular Insufficiency

BACKGROUND

Hip dysplasia is the leading cause of hip arthritis in young adults. These patients often participate in active lifestyles that require a full and stable range of motion.

METHODS

Between 2001 and 2011, 232 consecutive polyethylene resurfacing arthroplasties were performed in 201 patients with advanced arthritis from severe acetabular insufficiency due to dysplasia. All patients had Crowe II or III disease. Their mean age at surgery was 43 years. A 2-piece cementless acetabular resurfacing shell with dome screws and a highly cross-linked polyethylene liner were implanted to provide secure fixation, early weight bearing, and a stable hip. Additional structural bone grafts and/or fixation were not used. A cemented or cementless resurfacing prosthesis was used on the femur.

RESULTS

During a mean follow-up of 10 years, 8 hips (3.5%) were converted to a total hip arthroplasty due to acetabular loosening (1), femoral neck fracture (2), femoral osteonecrosis (2), infection (2), or persistent pain (1), resulting in a mean survival of the resurfacing prostheses of 96% (95% confidence interval 89-98). There were no pending revisions and no dislocations. At 2 years postoperative, Harris Hip Scores improved from a preoperative mean of 55 to 97 and University of California Los Angeles activity scores improved from 5 to 8.

CONCLUSION

Hip resurfacing using a 2-piece polyethylene acetabular component for advanced dysplasia has resulted in excellent function and implant survivorship with a low rate of complications at mid-term follow-up.

Inferomedial Hip Center Decreases Failure Rates in Cementless Total Hip Arthroplasty for Crowe II and III Hip Dysplasia

BACKGROUND

We sought to evaluate the outcomes of cementless acetabular components used in patients with Crowe II and III dysplasia, and to compare outcomes between cups placed within vs outside of an "anatomic" zone. Our specific aims were to (1) plot hip centers in these patients at our institution to characterize "anatomic" vs "nonanatomic" positions, (2) evaluate the association between hip center and radiographic loosening, (3) determine whether hip center was associated with acetabular component revision, and (4) compare patient-reported outcome scores between groups.

METHODS

We retrospectively reviewed 88 primary cementless total hip arthroplasties at a mean follow-up of 10 years (range 2-26 years). Patients were 85% female, with a mean age of 44 years (range 28-61 years) and a body mass index of 27 kg/m² (range 19-42 kg/m²). Medical records and radiographs were reviewed, and a survey was conducted for all patients. Anatomic hip center was defined using the 4-zone system, wherein centers are "anatomic" if they are <1 cm superior and <1 cm lateral to the approximate femoral head center. Cox proportional analyses were used to compare outcomes between groups.

RESULTS

Seventy hips (80%) had an anatomic hip center. Anatomic hips had a lower incidence of radiographic acetabular loosening (0% vs 17%, P = .007) and cup revision (0% vs 28%, P = .0002). There were no differences in Hip Disability and Osteoarthritis Outcome and Joint Replacement Scores (96.2 ± 5 vs 91.9 ± 12, P = .7).

CONCLUSION

The incidence of aseptic loosening and cup revision were lower when hip center was <1 cm superior and 1 cm lateral to the approximate femoral head center.

Clinical Results of Total Hip Arthroplasty in Two Patients with Charcot Hip Joints due to Congenital Insensivity to Pain with Anhydrosis

Traditionally, Charcot arthropathy has been considered an absolute contraindication for total hip arthroplasty (THA). However, some recent reports have shown that good short- to mid-term results can be achieved by improving the durability of the implant. This paper reports the mid- to long-term results of THA in two patients with Charcot hip joints caused by congenital insensivity to pain with anhydrosis. Both patients suffered multiple posterior dislocations in the six months immediately following surgery. However, with the continuous use of a hard abduction brace, one patient was eventually able to walk with a lofstrand cane and the other with the use of one crutch. Although one patient experienced a dislocation five years after surgery, X-rays taken after nine years and five years, respectively, revealed no clinical signs of implant loosening. We conclude that, with careful planning and appropriate precautions, THA may be a viable treatment option for Charcot hip joints caused by congenital insensivity to pain with anhydrosis.

A simple technique to strengthen the initial and mid-term to long-term stability of the cup during total hip arthroplasty in developmental dysplasia of the hip

Objectives:

To assess the effects of a technique of cup blocking screws combined with impaction bone grafting during total hip arthroplasty (THA) for patients with developmental dysplasia of the hip (DDH).

Methods:

From August 2011 to July 2015, 53 patients (59 hips) with DDH in our hospital were treated with THA using the technique of cup blocking screws combined with impaction particulate bone grafting. These patients were prospectively followed, and the clinical and imaging results were collected.

Results:

Harris hip score (HHS) was raised from 41.24 before surgery to 91.49 at the latest follow-up (p<0.001). Length discrepancy (LLD) was reduced from 28.97 mm before surgery to 6.08 mm after surgery (p<0.001). No loosening of the cup was detected at the last follow-up. The differences were insignificant in cup inclination and rate of cup coverage among the 3 groups of Crowe type II, type III, and type IV DDH (p>0.05).

Conclusion:

The technique of cup blocking screws combined with impaction particulate bone grafting is simple and reliable, and it not only simplifies the attainment of initial stability, but also strengthens the mid-term to long-term stability during THA in DDH.

Computed Tomographic Evaluation of Bone Stock in Patients With Crowe Type III Developmental Dysplasia of the Hip: Implications for Guiding Acetabular Component Placement Using the High Hip Center Technique

BACKGROUND

We evaluated acetabular cup coverage (CC) and rim contact (RC) to evaluate the bone stock above the acetabulum for guiding acetabular component placement using the high hip center technique in patients with Crowe type III developmental dysplasia of the hip.

METHODS

Using hip computed tomography and image processing software, pelvises were reconstructed digitally in 20 hips with Crowe type III developmental dysplasia of the hip. Mimicked cup was placed with anteversion angles of 0° (group I), 5° (group II), and 10° (group III) respectively. In each group, the cup was placed at the anatomical hip center at first, and then the cup was moved up to 40 mm vertically about the native rotation center with an increment of 2.5 mm at each step. CC and RC were calculated and documented with each movement.

RESULTS

CC was 65.87%, 67.77%, and 68.98% for group I, group II, and group III at the native rotation center, and increased progressively to 86.45%, 85.85%, and 84.71% at 25 mm above. RC was 49.17%, 50.25%, and 51.92% for group I, group II, and group III at the native rotation center, and increased progressively to 86.87%, 86.39%, and 84.94% at 22.5 mm above. CC and RC were positively correlated, despite the different anteversion angles (r = 0.687 at 0°, 0.683 at 5°, and 0.645 at 10°; P < .001).

CONCLUSION

Computed tomography analysis and computer stimulation demonstrate that it is feasible to use high hip center technique in Crowe type III hips.

Acetabular Reconstruction With the Medial Protrusio Technique for Complex Primary and Revision Total Hip Arthroplasties

BACKGROUND

In the setting of acetabular deficiency during total hip arthroplasty (THA), the medial protrusio technique (MPT) allows for increased component coverage while avoiding excessive component abduction or elevation of the hip center. The technique involves controlled reaming through the medial acetabular wall while maintaining the continuity of the anterior and posterior columns. The purpose of this study is to analyze the results of the largest reported series to date of primary and revision THAs using the MPT.

METHODS

A retrospective review of THAs performed by a single surgeon from July 2004 to July 2010 identified 102 patients who underwent THA necessitating the use of the MPT (primary 86 and revision 16), with at least 2 years follow-up.

RESULTS

This study reports the largest series to date of primary and revision THAs using the MPT for acetabular deficiency. Postoperatively, mean Harris hip score was 86 (range 31-96). There was no correlation with degree of medialization and change in Harris hip score (P = .12). At mean follow-up of 41.1 months (range 24-92 months), there were no intrapelvic structure injuries and no acetabular components required revision. The MPT provided a safe and effective method for addressing acetabular deficiency and avoiding component malposition.

CONCLUSION

The MPT provided a safe and effective method for addressing acetabular deficiency in this large series of patients. The technique was successful at improving component coverage while maintaining an anatomic hip center and avoiding excessive component abduction. Fixation remained durable with no cases of loosening at final follow-up.

Challenges in Total Hip Arthroplasty in the Setting of Developmental Dysplasia of the Hip

BACKGROUND

Developmental dysplasia of the hip (DDH) is a recognized cause of secondary arthritis, which may eventually lead to total hip arthroplasty (THA). An understanding of the common acetabular and femoral morphologic abnormalities will aid the surgeon in preparing for the complexity of the surgical case.

METHODS

We present the challenges associated with acetabular and femoral morphologies that may be present in the dysplastic hip and discuss surgical options to consider when performing THA. In addition, common complications associated with this population are reviewed.

RESULTS

The complexity of THA in the DDH patient is due to a broad range of pathomorphologic changes of the acetabulum and femur, as well as the diverse and often younger age of these patients. As such, THA in the DDH patient may offer a typical primary hip arthroplasty or be a highly complex reconstruction. It is important to be familiar with all the subtleties associated with DDH in the THA population. The surgeon must be prepared for bone deficiency when reconstructing the acetabulum and should place the component low and medial (at the anatomic hip center), and avoid oversizing the acetabular component. Femoral dysplasia is also complex and variable, and the surgeon must be prepared for different stem choices that allow for decoupling of the metaphyseal stem fit from the implanted stem version. In Crowe III and IV dysplasia, femoral derotation/shortening osteotomy may be required. Many complications associated with THA in the DDH patient may be mitigated with careful planning and surgical technique.

CONCLUSION

Performed correctly, THA can yield excellent results in this complex patient population.

Reliability of the acetabular reconstruction technique using autogenous bone graft from resected femoral head in hip dysplasia: Influence of the change of hip joint center on clinical outcome

INTRODUCTION

The previous studies have not reached on consensus as to the outcome of acetabular reconstruction with autogenous bone graft for dysplastic hips, especially in severe cases such as Crowe type IV. The current study aimed to determine the survivorship of the arthroplasty and the grafts as well as the change of hip joint center averagely 9.8 years (range, 5-19) after cementless total hip arthroplasty.

MATERIALS AND METHODS

We reviewed 52 cases including 19 cases of complete hip dislocation of which acetabular defects were augmented with autogenous bone grafts taken from the resected femoral heads. For radiographic evaluation, in addition to checking failures of THA, acetabular coverages of the grafts as well as lateral center-edge angles were measured and compared between two time points, immediately postoperative and the final evaluations. Those outcomes were also analyzed according to the degree of hip dysplasia, grouping the subjects by Crowe classification. Translations of the reconstructed hip joint center after THA were measured and checked if they affected clinical outcomes or caused any complications. To assess clinically, Harris hip score and visualized analogue pain scale were reviewed.

RESULTS

Mean coverage ratio of the sockets with the grafts was 28.4% immediately after the surgery (range, 11.1%-65.0%) and 27.2% at the final follow-up (range, 11.1%-63.6%). When comparing high grade dysplasia (Crowe type III, IV) to low grade dysplasia (Crowe type I, II), there was no significant difference of the above outcomes (p = 0.476). As to the location of hip joint center, 14 outliers were located distally within the normal horizontal range especially in cases with Crowe type IV. Those outliers showed no difference on clinical outcome. The mean HHS was 52.2 (range, 19-87) and VAS was 7.2 (range, 5-9) preoperatively, each of which was improved to 92.9 (range, 63-100) and 1.4 (range, 0-4) postoperatively. No failures were experienced during the study period.

CONCLUSIONS

Acetabular augmentation using autogenous bone graft from the resected femoral head is found to be a successful method for dysplastic hip, even in severe cases such as Crowe type IV, showing favorable results in more than 8 years. When inevitable, a degree of compromise on hip joint center can be needed in dealing with severe hip dysplasia.

Minimum Lateral Bone Coverage Required for Securing Fixation of Cementless Acetabular Components in Hip Dysplasia

Objectives. To determine the minimum lateral bone coverage required for securing stable fixation of the porous-coated acetabular components (cups) in hip dysplasia. Methods. In total, 215 primary total hip arthroplasties in 199 patients were reviewed. The average follow-up period was 49 months (range: 24–77 months). The lateral bone coverage of the cups was assessed by determining the cup center-edge (cup-CE) angle and the bone coverage index (BCI) from anteroposterior pelvic radiographs. Further, cup fixation was determined using the modified DeLee and Charnley classification system. Results. All cups were judged to show stable fixation by bone ingrowth. The cup-CE angle was less than 0° in 7 hips (3.3%) and the minimum cup-CE angle was −9.2° (BCI: 48.8%). Thin radiolucent lines were observed in 5 hips (2.3%), which were not associated with decreased lateral bone coverage. Loosening, osteolysis, dislocation, or revision was not observed in any of the cases during the follow-up period. Conclusion. A cup-CE angle greater than −10° (BCI > 50%) was acceptable for stable bony fixation of the cup. Considering possible errors in manual implantation, we recommend that the cup position be planned such that the cup-CE angle is greater than 0° (BCI > 60%).

Reconstruction of the Shallow Acetabulum With a Combination of Autologous Bulk and Impaction Bone Grafting Fixed by Cement

BACKGROUND

Acetabular bone deficiency, especially proximal and lateral deficiency, is a difficult technical problem during primary total hip arthroplasty (THA) in developmental dysplasia of the hip (DDH). We report a new reconstruction method using a medial-reduced cemented socket and additional bulk bone in conjunction with impaction morselized bone grafting (additional bulk bone grafting method).

QUESTIONS/PURPOSES

In a population of patients with acetabular dysplasia undergoing THA using a medial-reduced cemented socket and additional bulk bone with impacted morselized bone grafting, we evaluated (1) the radiographic appearance of bone graft; (2) the proportion of cups that developed loosening and subsequent revision; and (3) clinical results (outcome scores and complications).

METHODS

Forty percent of 330 THAs for DDH performed at one center between 1999 and 2009 were defined as shallow dysplastic hips. The additional bulk bone grafting method was performed on 102 THAs with shallow acetabulum (31% for DDH) at one center between 1999 and 2009. We used this approach and technique for shallow acetabuli when a cup protruded from the lateral acetabular edge in preoperative templating. The other 132 dysplastic hips without bone grafting had THA performed at the same periods and served as a control. Acetabuli were defined as shallow when the depth was less than or equal to one-fifth of the pelvic height (cranial-caudal length on radiograph). The additional bulk bone grafting technique was as follows: the resected femoral head was sectioned at 1 to 2 cm thickness, and a suitable size of the bulk bone graft was placed on the lateral iliac cortex and fixed by poly-L-lactate absorbable screws. Autologous impaction morselized bone grafting, with or without hydroxyapatite granules, was performed along with the implantation of a medial-reduced cemented socket. We defined an "incorporated" graft as remodeling and trabeculation including rounding off of the protruding edge of a graft beyond the socket. Radiographic criteria used for determining loosening were migration or a continuous radiolucent zone between the prosthesis/bone cement and host bone. Clinical outcomes were assessed using the Japanese Orthopaedic Association (JOA) and the Merle d'Aubigne and Postel score; complications were tallied from chart review. The followup was 10 ± 3 years (range, 6-15 years).

RESULTS

One acetabular component (1%) with severe shallow and steep acetabuli showed definite radiographic evidence of loosening and was revised. Clinically, the mean JOA score for the hips treated with additional bulk bone grafting THA in this study improved from 39 ± 10 points preoperatively to 95 ± 5 points postoperatively (p < 0.05, paired t-test). The mean Merle d'Aubigne and Postel score for the hips improved from 7 ± 2 points to 17 ± 1 points (p < 0.05, paired t-test). Complications included a Trendelenburg sign in one hip, dislocation in one, and transient partial sciatic nerve palsy in one. Within 3 years 6 months postoperatively, 101 of 102 additional bulk bone grafting cases showed successful bone remodeling and bone graft reorientation without collapse on radiographs. Partial resorption of the additional bone graft on the lateral side was observed in two hips (2%) with socket abduction angles of < 35°.

CONCLUSIONS

Achieving stable acetabular fixation is often challenging in the dysplastic hip, especially shallow acetabulum, and a variety of techniques have been described. Early results of combining bulk graft with impaction of morselized graft are promising. Although each surgical technique was well established, further investigation for clinical results of a combination of these techniques might be necessary to confirm longer term outcomes.

LEVEL OF EVIDENCE

Level IV, therapeutic study.

The necessity to restore the anatomic hip centre in congenital hip disease

Total hip replacement (THR) is the treatment of choice for the patient suffering from end-stage hip osteoarthritis. In the presence of deformities due to congenital hip disease (CHD), THR is, in most of the cases, a difficult task, since the technique of performing such an operation is demanding and the results could vary. We present our experience and preferred strategies focusing on challenges and surgical techniques associated with reconstructing the dysplastic hip.

Total hip arthroplasty without femoral osteotomy in patients who had high and low dislocation due to developmental dysplasia of the hip

BACKGROUND

Various surgical techniques and outcome results have been reported after primary total hip arthroplasty for the treatment of patients dysplastic hips. Low failure and complication rates have been reported when the acetabular component has been placed in the true acetabulum. The current study reports the results of primary total hip arthroplasty in patients with high and low dislocation for whom the acetabular component was placed in the true acetabulum without femoral or trochanteric osteotomy.

METHODS

26 primary total hip replacements were performed on 22 patients. The mean duration of follow-up was 8.9 years.There were 4 men and 18 women. 17 hips were classified as type B (low dislocation) and 9 as type C (high dislocation), according to the classification system of Hartofilakidis et al. Acetabular components were placed in the true acetabulum without osteotomy for all patients.

RESULTS

At the time of final follow-up (mean 8.9 years) the average Harris Hip Score was 85 points. Femoral head autograft was used in 9 hips to supplement acetabular coverage. In 8 patient linear calcar fracture. 7 fixed with Dall-Mile cable and 1 fixed with a side plate. On radiologic evaluation, 2 incidents of asymptomatic osteolysis, 1 of acetabular loosening, 1 graft resorption, and 1 impingement (correlated with physical examination) were identified. 2 patients had neuropraxia and were treated medically. There were no early or late infections. Only 1 patient with acetabular loosening required revision surgery.

CONCLUSIONS

Although it is surgically difficult to place the acetabular component in the true acetabulum without femoral or trochanteric osteotomy, at the final follow-up we report favourable results. Long-term follow-up is needed to verify our results.

Favorable Results of Primary Total Hip Arthroplasty With Acetabular Impaction Bone Grafting for Large Segmental Bone Defects in Dysplastic Hips

BACKGROUND

The aim of the present study was to assess midterm results after acetabular impaction bone grafting (IBG) in primary total hip arthroplasty (THA) for developmental dysplasia of the hip (DDH) with large acetabular segmental defect.

METHODS

Primary THA with IBG for DDH with large acetabular segmental defect was performed in 40 hips of 38 patients. The average age was 61.6 years (range: 33-82 years), and the average follow-up period was 7.5 years (range: 3-10.3 years). The Merle d'Aubigné and Postel hip score and complications were assessed. For radiological assessment, postoperative location of the hip rotation center, the socket inclination angle, and the socket center-edge angle were assessed. Kaplan-Meier survival analysis was performed with the end points of any type of reoperation and aseptic acetabular loosening.

RESULTS

The mean Merle d'Aubigné and Postel hip score improved from 10.4 points to 16.2 points at the final follow-up. Reoperation was performed in 1 case for acute infection without loosening. In 39 out of 40 hips (97.5%), the center of hip rotation was located beneath the "high hip center." The average socket inclination angle was 39.3° (range: 30°-54°), and the average socket center-edge angle was -11.8° (range: -23° to 9°). Survival rate of acetabular component at 8 years with the end point of any reoperation and of aseptic loosening was 96.6% (95% confidence interval: 89.9%-100%) and 100%, respectively.

CONCLUSION

Acetabular IBG represents one of the useful options for restoring a normal hip center and acetabular bone stock in primary THA for DDH with large acetabular defect.

Medial Protrusio Technique in Cementless Total Hip Arthroplasty for Developmental Dysplasia of the Hip: A Prospective 6- to 9-Year Follow-Up of 43 Consecutive Patients

BACKGROUND

The medial protrusio technique may be used during total hip arthroplasty (THA) on patients with developmental dysplasia. However, studies have yet to determine whether a cementless cup can be sufficiently stable to withstand loading forces. This study aimed to assess the clinical and radiographic outcomes of this technique. Furthermore, we sought to determine the relationship between the rate of medial protrusion and the incidence of cup loosening.

METHODS

Thirty-nine patients (43 hips) underwent cementless THA between April 2006 and March 2009 by using the medial protrusio technique. These patients participated in a 6- to 9-year follow-up. Their clinical and radiographic data were gathered prospectively.

RESULTS

The average Harris Hip Score improved from 43.1 ± 15.4 points preoperatively to 91.9 ± 12.8 points at the final follow-up (P < .001). The mean height of hip center and the distance of hip center medialization were 2.4 ± 0.6 and 2.5 ± 0.9 cm, respectively. The rate of medial protrusion and the rate of cup coverage were 42.1 ± 12.4% and 96.8 ± 5.1%, respectively. The rate of medial protrusion ranged from 18.3% to 58.3% in 38 hips (group A) and from 61.3% to 68.9% in 5 hips (group B). None of the cups in group A loosened or failed, 2 failures occurred in group B (0% vs 40.0%; P = .011).

CONCLUSIONS

Developmental dysplasia was treated through THA using the medial protrusio technique, which easily achieves a sufficient superolateral host bony coverage of the cup and promotes socket reconstruction at the true acetabulum. The rate of medial protrusion of <60% may be necessary to obtain excellent clinical and radiographic midterm results.

Acetabuloplasty at the anatomic centre for treating Crowe class III and IV developmental hip dysplasia: a case series

INTRODUCTION

Total hip replacement in patients with developmental dysplasia of the hip (DDH) is a difficult technical procedure for surgeons to perform because of the potential for these patients to have severe anomalies in their bones and soft tissues.

MATERIALS AND METHODS

We performed acetabuloplasty in 54 hips from 44 patients by reaming the posterior wall of the native acetabulum and medialising the acetabular component to restore the anatomic centre of hip rotation using a small cup without bone grafting. Median time to post-surgery follow-up was 5 (range 2-14) years.

RESULTS

Prosthetic survival rates in patients after 2 and 5 years post hip replacement were 93% (50/54) and 89% (48/54), respectively. 4 patients required early revision because of malposition and instability of the acetabular cup. 3 patients with Crowe type IV dislocations had transient sciatic nerve palsy and 3 had deep vein thrombosis.

CONCLUSIONS

Placement of the acetabular shell using posterior bone stock to provide normal hip rotation is a successful alternative technique for acetabuloplasty in patients with DDH.

Uncemented total hip arthroplasty in osteoarthritis of hip secondary to low and high dislocated hips: A mid-term follow-up study

Background:

Performing successful total hip replacement (THR) in dysplastic, subluxed, and dislocated hip is a challenging task. Here, we assessed midterm clinical and radiological outcomes of uncemented total hip arthroplasty in osteoarthritis (OA) of hip secondary to Hartofilakidis low and high-dislocated hips with a mean follow-up of 8.8 years.

Materials and Methods:

A retrospective study of prospectively collected data was designed involving all consecutive patients who underwent uncemented THR for OA of hip secondary to developmental dysplasia of the hip and Grade II or Grade III Hartofilakidis classification.

Results:

Thirty-two patients underwent 45 THR, with 23 Grade II (low dislocation) and 22 Grade III (high-dislocation) of Hartofilakidis classification. Thirteen patients had bilateral hip replacements, 19 patients had unilateral THR. There was highly statistically significant difference between preoperative and postoperative HHS and SF-36v2™ at each follow-up. Survivorship of original implant was 98.88% at a mean follow-up of 8.8 years. The mean improvement in leg length in this series was 3.6 cm (1.8-4.5, 95% confidence interval). No sciatic nerve or femoral nerve palsies were observed.

Conclusions:

Uncemented THR provides better function and quality of life. However, longer follow-up studies are needed to assess survivorship of uncemented THR in Hartofilakidis low and high-dislocations.

Anatomic Hip Center Decreases Aseptic Loosening Rates After Total Hip Arthroplasty with Cement in Patients with Crowe Type-II Dysplasia: A Concise Follow-up Report at a Mean of Thirty-six Years

We previously reported the two to twenty-two-year results of 145 total hip arthroplasties (THAs) with cement performed from 1969 to 1980 in 117 patients with Crowe type-II dysplasia. The purpose of the present study was to update the long-term effects of a nonanatomic hip center on component loosening and aseptic revision in this cohort. Forty-nine patients (sixty hips) were alive at a mean of thirty-six years. The overall cumulative incidence of aseptic revision at thirty-five years was 32% for acetabular cups and 21% for femoral stems. Acetabular loosening was less likely with a hip center placed within the true acetabular region (TAR), <15 mm superior to the approximate femoral head center (AFHC), <35 mm superior to the interteardrop line (ITL), or within zone 1. Femoral loosening and revision were less likely with the hip center placed <35 mm superior to the ITL and within zone 1. An anatomic hip center was associated with significantly lower loosening and aseptic revision rates for both acetabular and femoral components. The current study supports the placement of acetabular components in an anatomic position to promote long-term durability after THA with cement.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Custom-made femoral implants in total hip arthroplasty due to congenital disease of the hip: a review

Congenital disease of the hip (CDH) is a common reason for the development of secondary osteoarthritis at the hip joint and the need for total hip arthroplasty (THA). The distorted femoral anatomy in patients with CDH in combination with soft tissue considerations and leg length discrepancy complicate the procedure of THA and this sometimes precludes the implantation of classical industry designed femoral stems. In such cases a customised femoral implant must be used in order to optimise the fit of the stem to the femur, to improve strain distribution and to reconstruct hip biomechanics. The present study reviews the preoperative planning, the design and material selection of custom-made implants, the surgical techniques and the reported clinical results of the published literature on the use of custom-made femoral implants in patients with CDH.

Small diameter acetabulum and femoral head in total hip arthroplasty for developmental dysplasia of the hip, with no femoral osteotomy

We present the results of 66 total hip arthroplasties in 62 patients of mean age 46 years (24-74 years), with developmental dysplasia of the hip. In all cases the centre of rotation of the new hip was positioned at the site of the true acetabulum. In all patients cementless press fit acetabular components of small diameter (42-44 mm) were used, articulating exclusively with a 22.25 mm modular metal femoral head, without the use of bone grafts or shortening osteotomies of the femur. Despite the use of small diameter femoral heads the rate of dislocation was 3%. After an average follow-up period of 9 years (4-18 years), no revisions were required for infection, loosening or wear or implant migration. Osteolytic lesions were seen in the periacetabular region in 3 patients who were symptom free. A total of 2 revisions were required for instability and 2 patients had the wires of their trochanteric osteotomy removed because of bursitis. Leg length inequality was improved in 55% of the patients and one postoperative transient sciatic nerve lesion settled within 4 months. We believe that in patients with painful dysplastic hips, the use of small diameter implants with the centre of rotation at the true acetabulum, can give very satisfactory results, without any supplementary procedures.

Midterm Outcome of Cementless Total Hip Arthroplasty in Crowe IV-Hartofilakidis Type III Developmental Dysplasia of the Hip

BACKGROUND

Developmental dysplasia of the hip (DDH) is widespread in developing countries, and treating Crowe IV-Hartofilakidis Type III DDH in adults requires the use of a highly demanding technique.

METHODS

We sought to determine the outcome of cementless total hip arthroplasty using Zweymüller components to treat Crowe IV-Hartofilakidis Type III DDH. Fifty-eight patients (71 hips) with a mean age of 35.8 years at time of index operation were included in our study. The average duration of follow-up was 70.5 months. The acetabular component was placed in the true acetabulum in all cases, and subtrochanteric shortening osteotomy was performed in 61 hips.

RESULTS

With any component revision for any reason as the end point, Kaplan-Meier survivorship analysis at 98 months revealed a cumulative survival rate for implanted components of 91.40%. The mean Harris Hip Score improved from 35.6 preoperatively to 82.9 postoperatively. There were 20 cases of intraoperative fracture, 1 case of complete nerve palsy, and 7 cases of transient nerve palsy. Revision surgery was performed in 7 patients because of cup loosening in 1, severe polyethylene wear in 4, cup breakage in 1, and dislocation in 1.

CONCLUSIONS

Midterm results for cementless total hip arthroplasty in patients with Crowe IV-Hartofilakidis Type III DDH was satisfactory; however, intraoperative fracture and polyethylene wear were major complications.

Application of Rapid Prototyping Pelvic Model for Patients with DDH to Facilitate Arthroplasty Planning: A Pilot Study

Total hip arthroplasty (THA) is challenging in cases of osteoarthritis secondary to developmental dysplasia of the hip (DDH). Acetabular deficiency makes the positioning of the acetabular component difficult. Computer tomography based, patient-individual three dimensional (3-D) rapid prototype technology (RPT)-models were used to plan the placement of acetabular cup so that a surgeon was able to identify pelvic structures, assess the ideal extent of reaming and determine the size of cup after a reconstructive procedure. Intraclass correlation coefficients (ICCs) were used to analyze the agreement between the sizes of chosen components on the basis of preoperative planning and the actual sizes used in the operation. The use of the 3-D RPT-model facilitates the surgical procedures due to better planning and improved orientation.

Favorable outcome of a total hip arthroplasty with insufficient bone coverage of the roof reinforcement ring

•

THA in patients with developmental dysplasia of the hip can be a complex procedure due to acetabular and proximal femoral deformities.

•

An adequate fixation of an acetabular roof reinforcement ring to the pelvis with cancellous bone screws is crucial for the stability of the prosthesis.

•

The conical femoral stem is an efficient implant. Optimum anteversion of the stem is possible with no technical difficulties.

Introduction

Total hip arthroplasty in patients with developmental dysplasia of the hip can be a complex procedure due to acetabular and proximal femoral deformities.

Presentation of case

A 59-year-old male patient underwent a total hip arthroplasty for the treatment of end-stage dysplastic osteoarthritis. A roof reinforcement ring, a cemented polyethylene cup, and a cementless stem were used. A portion of the superior rim of the ring was uncovered by the host bone. Morsellized autogenous femoral-head graft was impacted to fill the space between the superior rim of the ring and the superior part of the dysplastic acetabulum. At the follow-up after 5-years, the patient had no complaints and was very satisfied with the operation result. The hip radiograph revealed no signs of instability of the acetabular component, and no bone graft resorption.

Discussion

Favorable results were described using metal rings and conical femoral stems for the treatment of the developmental dysplasia of the hip. The superior rim of the metal ring should be against host bone for 60% of its support. Despite the suboptimal implantation of the ring compromising, apparently, mechanical stability of the arthroplasty, the outcome was favorable.

Conclusion

This result can be supported by the good fixation of the metal ring to the pelvis with screws, the adequate orientation of both components of the total hip arthroplasty, and the bone graft incorporation.