Complex Primary Total Hip Arthroplasty Research Articles

SHORT-TERM OUTCOME OF A MODERN MONOBLOCK TITANIUM FLUTED TAPERED REVISION STEM FOR COMPLEX PRIMARY AND REVISION TOTAL HIP ARTHROPLASTY

For over a decade, modular titanium fluted tapered (TFT) stems have demonstrated excellent clinical success for femoral revision total hip arthroplasty (THA) surgery. The aim of this study was to report the short-term outcomes of a novel modern monoblock TFT stem used for revision and complex primary THA with a minimum of 2 years follow-up.We identified 126 patients who received a single monoblock TFT stem - 26 patients for complex THA (failed fracture fixation) and 100 patients for revision THA. The reasons for revision THA included 40 for previous prosthetic joint infection (PJI), 42 for aseptic loosening, 9 for trunnionosis, 9 for periprosthetic fractures. The Paprosky grading for femoral bone loss at the time of surgery and the measured subsidence of femoral stems at 3 months follow-up were determined. We evaluated the number and indications for re-operations.The mean time from surgery was 3.9 years (range 2.0 to 6.9 years). A paired t-test analysis showed significant improvement from pre-operative versus post-operative clinical outcome scores (p<0.001) for HHS (38.76 +/- 15.24vs. 83.42 +/- 15.38), WOMAC (45.6 ± 19.0 vs. 69.9 ± 21.3) and SF-12 Physical component (31.7 ± 8.1 vs. 37.8 ± 11.3) and SF-12 Mental component (48.2 ± 12.2 vs. 51.6 ± 12.5). The Paprosky grading for femoral bone loss was Grade 1 (3.9%), Grade 2 (35.7%), Grade 3A (47.6%), Grade 3B (11.1%) and Grade 4 (1.6%) cases. There were 18 re-operations (14.7%) with 13 for PJI (7 treated with implant retention, 6 treated with a two-staged revision), 4 for instability and one for acetabular aseptic loosening. There were no aseptic failures of the stem.This novel modern monoblock TFT stem provided reliable femoral fixation and has increasingly supplanted the use of modular TFT stems for complex primary and revision surgery in our institution.

Total Hip Arthroplasty Combined with Proximal Femoral Reconstruction Effectively Treats Severe Hip Deformities: A Novel Osteotomy Technique.

Total hip arthroplasty (THA) combined with proximal femoral reconstruction is a novel osteotomy technique developed to address severe hip deformities. There is a paucity of robust clinical and radiological evidence regarding the outcomes of this novel osteotomy technique. This study aimed to evaluate the clinical and radiological outcomes of THA combined with proximal femoral reconstruction during the early follow-up. This is a retrospective case series of 63 hips who underwent THA combined with proximal femoral reconstruction at a single institution between January 2020 and July 2023. The mean age of patients was 39.6 ± 12.6 years. The mean follow-up was 25.6 ± 3.8 months. Surgical characteristics and perioperative variables were evaluated to assess the efficacy of this technique. Harris hip score (HHS) was utilized to evaluate hip function. Leg length discrepancy (LLD) was evaluated in X-ray. The incidence of major adverse events including deep vein thrombosis (DVT), osteolysis, nonunion of the osteotomy, intraoperative femoral fracture, and infection was also evaluated. Paired-samples t-test was used to compare preoperative and postoperative HHS and LLD. The mean operative time was 125.1 min. The mean size of the acetabular components used was 45.2 mm, and the stem size was 7.5. The primary friction interface was ceramic-on-ceramic, accounting for 92.1% of cases. The average length of hospital stay was 8.5 days. The mean cost of treatment was 46,296.0 Yuan. There was a significant improvement in postoperative HHS (p < 0.001) and LLD (p < 0.001) compared to preoperative values. The incidence of deep venous thrombosis was 4.8%; osteolysis rates for the cup and stem were 4.8% and 6.4%, respectively. The non-union and dislocation rates were 1.6% and 3.2%, respectively. There was no incidence of postoperative infection. The novel osteotomy surgical procedure yields reliable and impressive clinical and radiological outcomes, with minimal complications. We advocate for its use in complex primary THA cases involving severe proximal femoral deformities.

Minimum 2-Year Outcomes of a Modern Monoblock Titanium Fluted Tapered Revision Stem for Complex Primary and Revision Total Hip Arthroplasty

BackgroundModular titanium fluted tapered (TFT) stems have demonstrated excellent clinical success for femoral revision total hip arthroplasty (THA) surgery. This study reports the short-term outcomes of a novel modern monoblock TFT stem used for revision and complex primary THA with a minimum of 2 years of follow-up. MethodsWe identified 126 patients who received a single monoblock TFT stem: 26 patients for complex THA (failed fracture fixation) and 100 patients for revision THA. The reasons for revision THA included 40 for previous periprosthetic joint infection, 42 for aseptic loosening, 9 for trunnionosis, and 9 for periprosthetic fractures. The Paprosky grading for femoral bone loss at the time of surgery and the measured subsidence of femoral stems at 3-month follow-up were determined. We evaluated the number and indications for reoperations. ResultsThe mean time from surgery was 3.9 years (range, 2.0 to 6.9). A paired t-test analysis showed significant improvement from preoperative versus postoperative clinical outcome scores (P < .001) for Harris Hip Score (38.76 ± 15.24 versus 83.42 ± 15.38), Western Ontario and McMaster Universities Arthritis Index (45.6 ± 19.0 versus 69.9 ± 21.3), Veterans RAND 12 Item Health Survey Physical component (31.7 ± 8.1 versus 37.8 ± 11.3), and Veterans RAND 12 Item Health Survey Mental component (48.2 ± 12.2 versus 51.6 ± 12.5). The Paprosky grading for femoral bone loss was Grade 1 (3.9%), Grade 2 (35.7%), Grade 3A (47.6%), Grade 3B (11.1%), and Grade 4 (1.6%) cases. There were 18 reoperations (14.7%), with 13 for periprosthetic joint infection (7 treated with implant retention and 6 treated with a 2-stage revision), 4 for instability, and 1 for acetabular aseptic loosening. There were no aseptic failures of the stem. ConclusionsThis novel modern monoblock TFT stem provided reliable femoral fixation and has increasingly supplanted the use of modular TFT stems for complex primary and revision surgery in our institution.

Using Three-Dimensional Printing Technology to Solve Complex Primary Total Hip Arthroplasty Cases: Do We Really Need Custom-Made Guides and Templates? A Critical Systematic Review on the Available Evidence.

An extensive literature review was conducted to retrieve all articles centered on the use of 3D printing in the setting of primary THA. A total of seven studies were included in the present systematic review. Four studies investigated the use of 3D-printed surgical guides to be used during surgery. The remaining three studies investigated the benefit of the use of 3D-printed templates of the pelvis to simulate the surgery. The use of 3D printing could be a promising aid to solve difficult primary total hip arthroplasty cases. However, the general enthusiasm in the field is not supported by high-quality studies, hence preventing us from currently recommending its application in everyday practice.

Greater Trochanteric Fixation Using Cable Plate Devices in Complex Primary and Revision Total Hip Arthroplasty.

Successful fixation of the greater trochanter (GT) in total hip arthroplasty (THA) is a challenging task. A wide range of clinical results are reported in the literature despite advancements in fixation technology. Previous studies may have lacked adequate sample sizes to detect differences. This study evaluates nonunion and reoperation rates and determines factors influencing successful fixation of the GT using current-generation cable plate devices. This retrospective cohort study included 76 patients who underwent surgery requiring fixation of their GT and had at least 1-year radiographic follow-up. Indications for a surgery were periprosthetic fracture (n= 25), revision THA requiring an extended trochanteric osteotomy (n= 30), GT fracture (n=3), GT fracture nonunion (n= 9), and complex primary THA (n= 3). Primary outcomes were radiographic union and reoperation. Secondary objectives were patient and plate factors influencing radiographic union. At a mean radiographic follow-up of 2.5 years, the union rate was 76.3% with a nonunion rate of 23.7%. Twenty-eight patients underwent plate removal, reasons for removal were pain (n= 21), nonunion (n= 5), and hardware failure (n= 2). Seven patients had cable-induced bone loss. Anatomic positioning of the plate (P= .03) and number of cables used (P= .03) were associated with radiographic union. Nonunion was associated with a higher incidence (+30%) of hardware failure due to broken cable(s) (P= .005). Greater trochanteric nonunion remains a problem in THA. Successful fixation using current-generation cable plate devices may be influenced by plate positioning and number of cables used. Plate removal may be required for pain or cable-induced bone loss.

Three-Dimensional Printed Models in Pre-Operative Planning of Complex Primary and Revision Total Knee Arthroplasty

Three-dimensional (3D) printing was introduced firstly for industrial use, but it gained popularity in different medical fields, including orthopedic surgeries. Particularly, 3D-printed models have been used in the pre-operative planning for spine surgery, oncology, acetabular fracture treatment and complex primary total hip arthroplasty (THA) or revision THA. In knee surgery, some authors described good accuracy with 3D-printed wedge for Opening Wedge High Tibial Osteotomy (OWHTO), but there are no studies describing its application in Total Knee Arthroplasty (TKA). In both primary and revision TKA, a 3D-printed model may be useful to better evaluate knee morphology and deformity, implants, bone losses and the compatibility between different components used. Furthermore, some companies provide a bone thickness evaluation, which may be useful to identify zones at risk of intra-operative fracture, especially in those cases in which a cone or sleeve must be used. The first aim of this manuscript was to evaluate possible application of 3D-printed model in pre-operative planning of both complex primary and revision TKA, compared to standard planning. Two clinical cases will also be described to show how these models can be used for planning purposes.

Direct Anterior Cup-Half Cage for Revision and Complex Primary Total Hip Arthroplasty: Surgical Technique.

As surgeons' comfort with the direct anterior approach (DAA) for total hip arthroplasty continues to increase, there is a growing interest in performing complex surgeries through this approach. Acetabular bone loss and/or pelvic discontinuity in the primary or revision setting often requires specialized implants such as a cup-cage construct. We describe our surgical technique for implanting modified cup-half cages through the DAA and show 2 case examples of how this technique was utilized in the setting of complex acetabular bone loss. In our experience, this is an effective method for complex total hip arthroplasty, with the potential added benefits of the DAA of reduced soft-tissue dissection, direct measurement of leg length, and ease of fluoroscopic navigation for implant positioning.

The Use of Robotic-Arm Assistance in Complex Primary Total Hip Arthroplasty: A Report of Three Challenging Cases

AbstractThe purpose of this case report was to demonstrate the utility, versatility, and efficacy of robotic-arm technology in complex primary total hip arthroplasty (THA) cases for acetabular bone loss, hip dysplasia, and post-traumatic arthritis with hardware. Preoperative computer templating allows precise and accurate acetabular and femoral stem positioning in cases that presented with significant native deformity and bone loss. Robotic-arm THA may be a viable option for complex primary cases to optimize implant positioning and mitigate postoperative instability and complications.

Midterm results of titanium conical Wagner stem with challenging femoral anatomy: Survivorship and unique bone remodeling

BackgroundComplex anatomy of the proximal femur makes total hip arthroplasty (THA) more challenging. Short, straight, fluted and conical titanium stem like the Wagner Cone can be helpful to address small femoral canal, increased femoral neck version, important leg length discrepancy or proximal femoral deformity. The outcome in these patients is less assured and associated with high rate of complications. Therefore, we did a retrospective study aiming to answer: 1) can the Wagner Cone stem provide acceptable mid- to long-term implant survivorship; 2) help minimizing perioperative adverse events; 3) produce favorable clinical outcome measured by WOMAC score; and 4) be associated with a favorable radiographic femoral bone remodeling at the last follow-up? HypothesisWagner Cone stem is an advantageous solution for the distorted proximal femur in complex THA. Patients and methodOur cohort was derived from the patient registries where medical records of 88 patients (103 hips) who underwent primary THA using the Wagner prosthesis were retrospectively reviewed. Then, data was analyzed for patients’ demographics and surgical data, and comparing preoperative, immediate postoperative and last follow-up data. Eleven patients (12 hips) were excluded (7 hips followed up less than 2 years or lost to follow-up, 3 hips that had the Wagner stem for revision and 2 Wagner stems inserted for periprosthetic fracture). This left 77 patients (91 hips) with Wagner cone stems implanted for more than 2 years between March 2003 and February 2017 by 7 surgeons in 3 academic hospitals. Implant revision, reoperations, WOMAC score and radiographic analyses were recorded at last follow-up. ResultsAfter a mean follow-up of 7.8 (range, 2.0–16.2) years, Wagner stem survivorship was 98.9% (95% CI: 94 to 100%) with one (1.1%) stem revision for failure of osteointegration. Five (5.5%) acetabular revisions, one for aseptic loosening, 2 for adverse reaction to metal debris and 2 for infection. One (1.1%) sciatic neuropathy and 4 (4.4%) intraoperative fractures were encountered. The mean WOMAC score was 90.5±11.4 (59–100). Radiographic analysis showed clear signs of stem osseointegration and hypertrophic bone remodeling in 82 cases (92.1%). ConclusionsUsed in complex cases with proximal distorted femurs, the Wagner Cone stem demonstrated a low complication rate, a high-rate consistent adaptive bone remodeling, excellent clinical results, and midterm survival. It is a safe, reliable and advantageous option in complex primary THA. However, the contribution of the underlying cause of the secondary osteoarthritis on the long-term survival of the stem remains to be demonstrated. Level of evidenceIV; retrospective study.

3D-планування і прототипування при складному первинному ендопротезуванні кульшового суглоба

Актуальність. Ендопротезування великих суглобів — одне з найбільш успішних оперативних втручань за останнє сторіччя. З кожним роком ми спостерігаємо збільшення кількості тотальних артропластик як у всьому світі, так і в нашій країні. Відповідно, зростає кількість різновидів імплантів і вдосконалюється методика їх імплантації. У випадку простого первинного ендопротезування передопераційне планування можна провести за допомогою стандартних шаблонів або відповідного програмного софта. При складному первинному ендопротезуванні, коли оперативному втручанню передували травми, остеотомії, операції остеосинтезу, провести повноцінне передопераційне планування без тривалої та трудомісткої підготовки дуже складно. Мета роботи: виконати аналіз передопераційного планування й інтраопераційної навігації при підготовці до складного первинного ендопротезування кульшового суглоба з використанням просторового 3D-моделювання та прототипування. Матеріали та методи. Наші пацієнти — 2 жінки та 1 чоловік, вік яких становив 31 рік, 48 та 56 років. Строк спостереження — від 6 до 19 місяців після тотального ендопротезування кульшового суглоба. Усі пацієнти раніше перенесли оперативні втручання в даній зоні. На етапах передопераційного обстеження була проведена мультиспіральна комп’ютерна та магнітно-резонансна томографія, на підставі цих даних були надруковані прототипи з пластика в натуральну величину. Було проведено передопераційне планування та складено план проведення оперативного втручання. Результати. Пацієнтам виконано тотальне ендопротезування кульшового суглоба з використанням імплантів механічної фіксації. У двох пацієнтів виконана коригуюча остеотомія проксимального відділу стегнової кістки. Одному пацієнтові проведена кісткова автопластика дна вертлюжної западини. Через 3 місяці після оперативного лікування спостерігалося повне відновлення функції, оцінка за шкалою Харріса становила 95,6 (95–97) бала. Висновки. Передопераційне планування — дуже важлива частина підготовки до оперативного втручання. При підготовці до складного первинного ендопротезування суглобів доцільно використання адитивних технологій для виготовлення пластикової моделі, що дозволить скласти детальний план майбутньої операції і буде виконувати функцію інтраопераційної навігації.

Clinical and Radiological Outcome of Acetabular Reconstruction Rings in Complex Primary and Revision Total Hip Arthroplasty.

Acetabular reconstruction in complex primary and revision total hip arthroplasty (THA) with bone loss poses a great challenge. We aim to evaluate the medium-term clinical and radiological outcome of reconstruction rings used in these difficult situations. We retrospectively reviewed a consecutive series of acetabular reconstructions with Muller ring or Bursh-Schneider cage from January 2009 to December 2016. The reconstruction rings were used in 66 hips (65 patients). There were 41 complex primary THA and 25 revision THA. The mean follow-up period was 76months (range, 37-167months). Clinical evaluation includes the assessment of Harris hip score, visual analogue scale (VAS) score, limb length discrepancy, and activities of daily living. The radiographs were analyzed for any signs of loosening, osteolysis, acetabular migration, and heterotopic ossification. The overall survival rate was 95% for revision in aseptic loosening and 87% for any reason at an average follow-up of 6.3years. Twelve patients died and 9 patients were lost to follow-up leaving 45 patients for final functional analysis. Among the 45 patients, excellent to good results were seen in 33 patients, fair results were seen in 5 patients, poor results were seen in seven patients. Two patients had aseptic loosening and another two patients developed deep chronic infection awaiting two-stage revision. Reconstruction rings still place a role in the armamentarium for complex acetabular reconstruction. It helps to reliably restore the bone stock, have an acceptable survival rate and satisfactory functional outcome at medium to long-term follow-up.

Long-Term Survivorship of Modular Cementless Femoral Stem in Complex Primary Total Hip Arthroplasty: A Concise Minimum 15-Year Follow-Up Report

BackgroundS-ROM hip is a well-established and versatile prosthesis that offers extensive metaphyseal and diaphyseal geometries providing solutions for a variety of surgical scenarios. The aim of this study is to report on long-term survivorship and radiographic outcomes of complex primary total hip arthroplasty (THA) using a modular cementless stem (S-ROM). MethodsRetrospective consecutive study was conducted of 167 patients (167 hips): 97 males and 70 females with average age at the time of surgery of 55 years (range 22-76). All patients underwent complex THA by the senior author from 1987 to 1999. Patients were identified using a prospective database. Demographic, clinical, and surgical data were collected from health records. All patients received a cementless acetabular component with a standard polyethylene liner. The primary outcome measure was survivorship beyond 15 years using stem revision for any cause as an end point. Secondary outcome measure was rate of radiographic loosening using Engh classification. ResultsOnly 3 patients required stem revision for aseptic loosening and 1 for periprosthetic fracture. Isolated acetabular revision was undertaken in 23 of 167 patients (13.8%) due to polythene wear, osteolysis, and aseptic loosening. Proximal femoral stress shielding (zone 1, 7) was noted in 34 of 167 hips (20.4%). Stable bony ingrowth was noted in 144 hips (86.2%) and the remaining 23 hips had stable fibrous ingrowth (13.8%). Using stem “any-cause revision” as an endpoint, the mean stem survivorship was 31.5 years (95% confidence interval 31.007-31.985) with 30-year estimated survivorship of 97.6%. ConclusionIn a single designer surgeon series, S-ROM stem has stood the test of time with long-term, 30-year survivorship of 97.6% and continues to play an important role in modern hip surgery providing longevity and versatility. However, further comparative long-term studies from independent centers are needed for a definitive conclusion. Level of EvidenceIV.

Complex Primary Total Hip Arthroplasty: Small Stems for Big Challenges.

Total hip arthroplasty is one of the most successful operations in all of medicine. Femoral deformities from malunion, prior osteotomy, and retained surgical implants all present unique challenges. Corrective osteotomy and hardware removal add significant morbidity to an operation that typically has a fast recovery. Short stems can be used in these cases to spare patients' increased morbidity. We present a case-based illustration and surgical technique for the use of short stems in complex primary total hip arthroplasty with femoral deformity and retained hardware. We discuss how these implants can spare significant morbidity, show radiographic examples of their use, and present short-term outcomes.

Augmentation for Acetabular Deficiencies in Complex Total Hip Arthroplasty

Introduction:Complex and revision Total Hip Arthroplasty (THA) is a challenging prospect in patients with acetabular bone deficiencies. Augmentation using allograft and trabecular metal (TM) are among some of the options in these situations. This study report the outcomes of 14 cases of complex and revision THA using acetabular augments performed in our institution between 2015 and 2018Materials and Methods:In this retrospective study, data included demographic features, indication for THA, type of augments and clinical outcomes using the Harris hip score were collected for the to determine early results following THA.Results:The mean cohort age was 51.3 years. Gender distribution was equal with 7 male and female patients each. 7 THAs were augmented with allograft and 7 cases with TM augments. The average duration of follow-up was 16.9 months. Most patients (11 of 14) required complex primary THA following prior traumatic hip dislocations and its subsequent complications. The mean post-operative Harris hip score for functionality was 80.84 in our cohort at final follow-up (from an average of 33.8 pre-operatively). At present, there have been no reports of wound complications, infections or dislocations in this early cohort.Discussions:Complex/revision THA using allografts for acetabular augmentation have been used for decades with good and replicable results as shown in our series. TM is relatively new but current literatures show encouraging results. Both options have resulted in good outcomes in our cohort and further long term studies would be necessary before TM augments were to replace the need for allograft.Conclusions:Both allografts and TM acetabular augments showed good early results post-operatively in our cohort. With the improved flexibility of component selection and the lower risk of allograft infection, TM augments is currently our choice of acetabular augmentation and the early results are promising.

Challenges in Primary Total Hip Arthroplasty

Total hip arthroplasty (THA) represents a meticulously standardized procedure with highly satisfactory results for surgeons and patients alike. Anyhow, due to rare diseases, anatomic varieties or in posttraumatic situations, the restauration of a normal hip joint anatomy and physiological kinematics can become a big challenge for the treating surgeon. This article gives an overview of the variety of these challenging conditions (including developmental hip dysplasia, osteopetrosis, skeletal dysplasia, Paget's disease and extraarticular deformities) and with a selection of complex cases it should give the reader some thought-provoking impulses considering the management of complex primary THA cases. This includes with the choice of implant, intraoperative characteristics, certain pitfalls and postoperative considerations alike. As a result, it should minimize the risk for complications in these complex cases without minimizing the patient's expectations in a nearly normal hip function and painless movement.

Novel technique for intraoperative sciatic nerve assessment in complex primary total hip arthroplasty: a pilot study.

Sciatic nerve injury (SNI) is a potentially devastating complication after total hip arthroplasty (THA). Intraoperative neural monitoring has been found in several studies to be useful in preventing SNI, but can be difficult to implement. In this study, we examine the results of using a handheld nerve stimulator for intraoperative sciatic nerve (SN) monitoring during complex THA requiring limb lengthening and/or significant manipulation of the SN. A consecutive series of 11 cases (9 patients, 11 hips) with either severe developmental dysplasia of the hip (Crowe 3-4) or other underlying conditions requiring complex hip reconstruction involving significant leg lengthening and/or nerve manipulation. SN function was monitored intraoperatively by obtaining pre- and post-reduction thresholds during component trialing. The results of nerve stimulation were then used to influence intraoperative decision-making. No permanent postoperative SN complications occurred, with an average increase of 28.5 mm in limb length, range (6-51 mm). In 2 out of 11 cases, a change in nerve response was identified after trial reduction, which resulted in an alternate surgical plan (femoral shortening osteotomy and downsizing femoral head). In the remaining cases, the stimulator demonstrated a response consistent with the baseline assessment, assuring that the appropriate lengthening was achieved without SNI. 1 patient had a transient motor and sensory peroneal nerve palsy, which resolved within 2 weeks. The intraoperative use of a handheld nerve stimulator facilitates surgical decision-making and can potentially prevent SNI. The real-time assessment of nerve function allows immediate corrective action to be taken before nerve injury occurs.

The Direct Anterior Approach for Complex Primary Total Hip Arthroplasty: The Extensile Acetabular Approach on a Regular Operating Room Table

BackgroundThe direct anterior approach on a regular operating room table has been reported with low dislocation rates. This might be beneficial for complex primary total hip arthroplasty (THA) such as in patients with cerebral palsy or following femoral or pelvic osteotomies. Extending the approach is often required to overcome problems such as acetabular deformities or severe contractures. MethodsWe retrospectively evaluated the results and complications of 29 patients with 37 complex primary THA in which an extensile approach was used. The extensile approach is described. Functional scores were collected in case the patient was ambulatory independently (n = 17). ResultsThe average age was 35 years (range 15-85) with a mean follow-up of 39 months (range 12-60). There were 3 (8%) intra-operative and 4 (11%) early post-operative complications (<3 months), of which 3 (8%) were anterior dislocations. Late complications (>3 months) consisted of a fibrous ingrown stem, a socket loosening following a pelvic fracture, and a late hematogenous infection (8%). Seventy-one percent of the complications occurred in the first 18 cases (49%) indicating a learning curve. The mean post-operative Harris Hip Score was 79 (range 56-97). ConclusionComplex THA can be safely conducted through the extensile anterior approach on a regular operating room table with the use of conventional implants, even in cases with a high risk of dislocation.

Can a Conical Implant Successfully Address Complex Anatomy in Primary THA? Radiographs and Hip Scores at Early Followup.

Total hip arthroplasty (THA) in patients with small or abnormal proximal femoral anatomy is challenging as a result of complex anatomic deformities in the hip. It is unclear which stem is the most appropriate for these patients. One possible implant design that may help meet this need is the modified Wagner Cone prosthesis, whose design consists of monoblock cone with splines; however, to our knowledge, no clinical results have been published using this implant. We evaluated the hip scores and radiographic results (including signs of osseointegration and subsidence) of complex primary THA using the modified Wagner Cone cementless femoral component in patients with small or abnormal proximal femoral anatomic proportions. Between 2006 and 2011, we performed 59 THAs on patients whose femoral geometry precluded the use of standard-sized implants. Of these, 49 (83%) received the modified Wagner Cone prosthesis. During this time, our indications for use of the Wagner Cone implant in such patients included: femoral neck retroversion, excessive anteversion of the femoral neck, or small proximal femora not suitable for standard implants. Of those, 40 patients with 49 THAs were available for radiographic and clinical followup at a minimum of 3 years, and no patients were lost to followup. The diagnosis included developmental dysplasia of hip (22 patients, 28 hips), secondary trauma or posttuberculosis osteoarthritis (nine patients, 10 hips), and hip disease secondary to other disorders (eight patients, nine hips) and osteonecrosis (one patients, two hips). Two versions of the stem with 135° (28 hips) or 125° (21 hips) neck angle versions were used to reestablish normal hip biomechanics. Version angle was chosen based on preoperative templating. Cementless cups with screws were used for the acetabulum. Mean followup was 4 years (range, 3-7 years). Study endpoints were the Harris hip score and radiographic evaluations by a surgeon not involved in the clinical care of the patients (QZ); radiographic analysis included evaluating for the presence or absence of signs of osseointegration (including Engh's criteria) and subsidence. The Harris hip score improved from a mean of 41 ± 9 preoperatively to a mean of 85 ± 10 at last followup (p < 0.01). The mean vertical subsidence was 1.5 ± 1.1 mm. Radiographic evaluation demonstrated stability (no further subsidence) of all implants at last followup. Endosteal spot welds were found in 32 hips (65%). No progressive radiolucencies were observed. One patient (one hip) underwent revision surgery as a result of late infection; no other revisions were performed. The modified Wagner Cone femoral stem has provided improvements in hip scores and promising short-term radiographic results at short-term followup in complex cementless THA associated with abnormal or small femoral anatomical proportions in which standard implants are inappropriate. Longer followup will be needed to see if these results endure. Randomized trials are needed to determine the optimal stem design for these patients. Level IV, therapeutic study.

(iii) Surgical tactics in the difficult primary hip replacement

Abstract The term complex primary total hip arthroplasty (THA) is used when THA is performed on patients with any combination of abnormal anatomy, bone loss and compromised soft tissues. This is often as a result of the development of secondary osteoarthritis complicating an underlying primary pathology. Those most commonly associated are developmental hip dysplasia, protrusio acetabuli, skeletal dysplasias, previous fractures or surgical procedures about the hip and neuromuscular conditions, but this is by no means an exhaustive list. The importance of preoperative planning and the use of reconstructive techniques including bone grafting, as well as the use of modular and customized implants to overcome these significant surgical challenges, are discussed.

A stemmed acetabular component in the management of severe acetabular deficiency

We evaluated the use of a stemmed acetabular component in the treatment of severe acetabular deficiency during revision and complex primary total hip arthroplasty. There were 31 hips of which 24 were revisions (20 for aseptic loosening, four for infection) and the remainder were complex primary arthroplasties. At a mean follow-up of 10.7 years (6 to 12.8), no component had been revised for aseptic loosening; one patient had undergone a revision of the polyethylene liner for wear. There was one failure because of infection. At the latest follow-up, the cumulative survival rate for aseptic loosening, with revision being the end-point, was 100%; for radiographic loosening it was 92% and for infection and radiographic loosening it was 88%. These results justify the continued use of this stemmed component for the reconstruction of severe acetabular deficiency.