Purpose. Minimally invasive anterolateral approach (ALA) for total hip arthroplasty (THA) has gained popularity in recent years as better postoperative functional recovery and lower risk of postoperative dislocation are claimed. However, difficulties for femur exposure and intraoperative complications during femoral canal preparation and component placement have been reported. This study analyzes the anatomical factors likely to be related with intraoperative complications and the difficulties of access noted by the surgeons through a modified minimally invasive ALA. The aim is to define the profile for patient at risk of intraoperative complications during minimally invasive ALA. Methods. We retrospectively included 310 consecutive patients (100 males, 210 females) who had primary unilateral THA using the same technique in all cases. The approach was performed between the tensor fascia lata and the gluteus medius and minimus, without incising or detaching muscles and tendons. Posterior translation was combined to external rotation for proximal femur exposure (Fig. 1). All patients were reviewed clinically and radiologically. For the radiological evaluation, all patients underwent pre- and postoperative standing and sitting full-body EOS acquisitions. Pelvic [Sacral slope, Pelvic incidence (PI), Anterior pelvic plane angle] and femoral parameters were measured preoperatively. We assessed all intraoperative and postoperative complications for femoral preparation and implantation. Intraoperative complications included the femoral fractures and difficulties for femoral exposure (limitations for exposure and lateralization of the proximal femur). The patients were divided into two groups: patients with or without intraoperative complications. Results. Ten patients (3.2%) had intraoperative femoral fractures (greater trochanter: 2 cases, calcar: 8 cases). Five fractures required additional wiring. Difficult access to proximal femur was reported in the operative records for 10 other patients (3.2%). There was no difference in diagnosis, age, sex, BMI between the patients with or without intraoperative complications. No significant group differences were found for surgical time, and blood loss. Patients with intraoperative complication, presented a significantly lower pelvic incidence than patients without intraoperative complications (mean PI: 39.4° vs 56.9°, p<0.001). The relative risk of intraoperative complications in patients with low PI (PI<45°) was more than thirteen times (relative risk; 13.3, 95% CI= 8.2 to 21.5. p<0.001) the risk for patients with normal and high PI (PI>45°). Conclusions. Anterolateral approach for THA implantation in lateral decubitus is reported to have anatomical and functional advantages. Nevertheless, the exposure of the femur remains a limitation. This study highlights a significant increased risk in case of low PI less than 45°. This specific anatomical pattern reduces the local working space as the possibility for posterior translation and elevation of the proximal femur is less on a narrow pelvis. This limitation is due to the length and the orientation of the hip abductor and short external rotator muscles related to the relative positions of iliac wing and greater trochanter (Fig. 2). This study points out the importance of pelvic incidence for the detection of anatomically less favourable patients for THA implantation using ALA. For any figures or tables, please contact the authors directly

The Dall approach is a modified anterolateral approach with osteotomy of the anterior part of the greater trochanter. This approach relatively preserves the soft tissue tension during total hip arthroplasty (THA). We insert the stem and select a ball neck size so as to have a stable hip which will not dislocate easily during the trial reduction. The aim of this study is to evaluate the adequacy of this method, to measure leg length discrepancy and offset discrepancy at postoperative radiographs. We selected patients for inclusion in this study from those who have more than a 120 degree of affected hip flection angle, the opposite hip is almost normal with a low leg length discrepancy (primary OA, osteonecrosis, Crowe 1 secondary OA, femoral neck fracture). All THA were performed with cement fixation using an alignment guide to ensure accurate acetabular positioning. The ball head's diameter used were all 26mm. From September 2011 to October 2013, 22 patients met inclusion criteria among 103 THA. The mean age for 22 subjects was 66.6±12 years. The mean flexion angle of preoperative hip joints was 127.2±6.1 degrees. The cup inclination was 43.8° ± 3.5°. Anteversion was 11.8°±6°. The mean preoperative leg length discrepancy was 5.8mm±6.3mm. The mean postoperative leg length discrepancy was 0.7±3.5mm. The mean postoperative offset discrepancy was 0.7±6.6mm. There were no dislocations in this series of 103 cases. Discussion. Dislocation and leg length discrepancies are major complications following a total hip arthroplasty. A good range of motion of the preoperative hip joint is considered a high risk dislocation factor. The Dall approach with minimal release of soft tissue related to a tension of hip joint offers maximal stability and the ability to accurately restore leg length

The purpose of this experimental study was to elucidate the accuracy of neck-cut PSG setting, and femoral component implantation using neck-cut PSG in the THA through the anterolateral-approach relative to the preoperative planning goals, and to determine the usefulness of PSG compared with the procedure without PSG. A total of 32 hips from 16 fresh Caucasian cadaveric samples were used and classified into 4 groups: cementless anatomical stem implantation with wide-base-contact PSG (AWP: 8 hips, Fig.2); (2) cementless anatomical stem implantation with narrow-base-contact PSG (ANP: 8 hips, Fig.2); (3) cementless anatomical stem implantation without PSG (Control: 8 hips); and (4) cementless taper-wedge stem implantation with wide-base-contact PSG (TWP: 8 hips). The absolute error of PSG setting in the sagittal plane of the AWP group was significantly less than that of the ANP (p=0.003).THA with wide-base- contact PSG resulted in better alignment of the femoral component than THA without PSG or with narrow- base-contact PSG. Although the neck-cut PSG did not control the sagittal alignment of taper-wedge stem, the neck-cut PSG was effective to realise the preoperative coronal alignment and medial height for THA via the anterolateral approach regardless of the femoral component type. For figures and tables, please contact authors directly

Introduction. Migration of the trial femoral head is a rarely occurring complication of total hip arthroplasty (THA) performed using the anterolateral approach (ALA). This migration of the trial femoral head under the rectus femoris is extremely risky because of the anatomical situation. Analyzing the morphological character of a case of migration may help us to avoid this risk. Objective. We analyzed the three-dimensional bone morphology using computed tomography (CT) scan images to investigate the physiological characteristics of five migration cases. Methods. We examined 108 patients (21 men, 87 women, 113 hips) who underwent THA via the ALA. The average patient age was 62.9 (range: 30–87) years and average body mass index was 24.4 (range: 18.0–36.0) kg/m2. The exclusion criteria were dysplastic coxarthroses greater than Crowe type II, previous fractures, previous hip operations, and muscle disease. Three-dimensional models of the pelvis and femur were made using ZedHip software® (Lexi, Tokyo, Japan). The anterior superior iliac spine on the affected side (A) and contralateral side (A’), anterior inferior iliac spine (I), and greater trochanter tip (G) were noted in these models. The distances A–I, I–G, and A–G and the angle formed by AA’ and AI were measured (Figure 1, 2). Each hip was classified by the presence (group M) or absence (group N) of migration during surgery. A Fisher's exact probability test, Student's t-test, and Welch's t-test were used to compare the two groups, and p-values less than 0.05 were considered significant. Results. In 5 of the 113 hips, the trial femoral heads migrated under the rectus femoris and were removed safely. No significant differences were found between the gender, height, weight, or BMI of the groups. The average A–I distance was 32.3±3.0 mm (mean±SD) in group M and 39.4±10.4 mm in group N; I–G was 52.2±8.2 mm in group M and 59.7±10.6 mm in group N; and A–G was 64.3±10.3 mm in group M and 76.3±12.3 mm in group N. The average angle formed by AA’ and AI was 50.5±5.8°. Significant differences between the two groups were found for the distances A–I and A–G. Conclusions. In 4.4% of cases, the trial femoral heads migrated under the rectus femoris, which creates a risk for serious complications because major nerve and blood vessels are located nearby. The tendency for migration was expected to be related to the balance between soft tissues. In this study, we found that migration tends to occur in patients with shorter distances between A and I, and A and G. The trial head should be dislocated more carefully in those patients

Aim. The objective of this study was to evaluate the intermediate term clinical and radiological results of a new short stem hip implant. Methods. In 20 consecutive patients suffering from osteoarthritis with 25 affected hip joints (five cases were bilateral), the clinical and radiological results of 25 hip arthroplasties performed in one hospital between October 2009 and May 2014 through a minimally invasive anterolateral approach using a cementless short stem prosthesis type Aida and a cementless cup type Ecofit with a ceramic on ceramic pairing were evaluated prospectively. The median age of patients at time of surgery was 60 years (range, 42–71 years), 15 male (4 were bilateral) and 5 female patients (one was bilateral) were included in the study. The median clinical follow up was 30 months (range, 2–88 months), and the median radiological follow up was 30 months (range, 2–88 months). Results. Harris Hip Score improved from a median preoperative value of 53 to a median postoperative value of 96 (range, 73–100) at follow up. 22 hips (88%) showed an excellent postoperative Harris Hip Score, 2 hips (8%) a good postoperative Harris Hip Score, and one hip (4%) a fair postoperative Harris Hip Score. Only two patients complained of postoperative thigh pain. Regarding patient satisfaction, 15 patients (60%) were very satisfied, 10 patients (40%) were satisfied. None was unsatisfied. Radiological analysis showed that 19 stems (76%) were with stable bony ingrowth, two cases (8%) showed stable fibrous ingrowth. Four cases need further follow up for proper evaluation of stem fixation.(See Figures 1,2,3). Conclusion. The intermediate term survival of this new short stem is very promising, and achieving the goals of a standard hip arthroplasty. For any figures or tables, please contact the authors directly

Hip abductor tears(AT) have long been under-recognized, under-reported and under-treated. There is a paucity of data on the prevalence, morphology and associated factors. Patients with “rotator cuff tears of the hip” that are recognized and repaired during total hip arthroplasty(THA) report comparable outcomes to patients with intact abductor tendons at THA. The study was a retrospective review of 997 primary THA done by a single surgeon from 2012–2022. Incidental findings of AT identified during the anterolateral approach to the hip were documented with patient name, gender, age and diagnosis. The extent and size of the tears of the Gluteus medius and Minimus were recorded. Xrays and MRI's were collected for the 140 patients who had AT and matched 1:1 with respect to age and gender against 140 patients that had documented good muscle quality and integrity. Radiographic measurements (Neck shaft angle, inter-teardrop distance, Pelvis width, trochanteric width and irregularities, bodyweight moment arm and abductor moment arm) were compared between the 2 groups in an effort to determine if any radiographic feature would predict AT. The prevalence of AT were 14%. Females had statistically more tears than males(18vs10%), while patients over the age of 70y had statistically more tears overall(19,7vs10,4%), but also more Gluteus Medius tears specifically(13,9vs5,3%). Radiographic measurements did not statistically differ between the tear and control group, except for the presence of trochanteric irregularities. MRI's showed that 50% of AT were missed and subsequently identified during surgery. Abductor tears are still underrecognized and undertreated during THA which can results in inferior outcomes. The surgeon should have an high index of suspicion in elderly females with trochanteric irregularities and although an MRI for every patient won't be feasible, one should always be prepared and equipped to repair the abductor tendons during THA

The direct lateral (or anterolateral) approaches to the hip for revision THA involve detachment of the anterior aspect of the gluteus medius from the trochanter along with a contiguous sleeve of the vastus lateralis. Anterior retraction of this flap of gluteus medius and vastus lateralis and simultaneous posterior retraction of the femur creates an interval for division of gluteus minimus and deeper capsular tissues and exposure of the joint. To enhance reattachment of this flap of the anterior portion of the gluteus medius and vastus lateralis back to the trochanter, an oblique wafer of bone can be elevated along with the muscle off of the anterolateral portion of the trochanter. This bony wafer prevents suture pull out when large nonabsorbable sutures are used around or through the fragment and passed into the bone of the trochanteric bed for reattachment during closure. To prevent excessive splitting proximally into the gluteus medius muscle (and resulting damage to the superior gluteal nerve), it is often helpful to extend the muscle split further distally down into the vastus lateralis. This combined with careful elevation of the gluteal muscles off of the ilium (instead of splitting them) helps provide excellent and safe exposure of the entire rim of the acetabulum and access to the supracetabular region for bone grafting, acetabular augment placement and even fixation of the flanges of a cage. A simple method for posterior column plating via the anterolateral approach involves contouring of the distal end of the plate around the base of the ischium at the inferior edge of the socket. When an extended osteotomy of the femur is needed to correct deformity, remove a well-fixed implant or cement, the “extensile” variation of this same surgical approach involves a Wagner style (lateral to medial) osteotomy of the greater trochanter and proximal femur. The anterior portion of the femur after it is osteotomised is elevated as a separate segment while maintaining the soft tissue attachments to the bone as much as possible to aid osteotomy healing. After implant or cement removal, this approach gives excellent direct access to the distal femur for placement of a long stem revision femoral component without bone-implant conflict proximally because of the bow of the femur. The anterolateral approach (and extensile variants detailed above) can be used routinely and safely in the full range of revision THA procedures, or it can be employed selectively, if desired, in cases at increased risk for dislocation

In 12 patients, we measured the oxygen concentration in the femoral head-neck junction during hip resurfacing through the anterolateral approach. This was compared with previous measurements made for the posterior approach. For the anterolateral approach, the oxygen concentration was found to be highly dependent upon the position of the leg, which was adjusted during surgery to provide exposure to the acetabulum and femoral head. Gross external rotation of the hip gave a significant decrease in oxygenation of the femoral head. Straightening the limb led to recovery in oxygen concentration, indicating that the blood supply was maintained. The oxygen concentration at the end of the procedure was not significantly different from that at the start. The anterolateral approach appears to produce less disruption to the blood flow in the femoral head-neck junction than the posterior approach for patients undergoing hip resurfacing. This may be reflected subsequently in a lower incidence of fracture of the femoral neck and avascular necrosis

Purpose. The purpose of this study was to compare and evaluate the cost-effectiveness of the MIS Anterolateral Approach to that of the MIS Posterolateral and MIS Direct Lateral Approach. Method. A prospective randomized control trial was designed and conducted to compare the MIS Anterolateral Approach to that of the MIS Posterolateral and MIS Direct Lateral Approach. Contemporary methods for economic evaluation were used to ascertain direct and indirect costs (in Canadian dollars) along with clinical effectiveness outcomes (SF6D and Pat5D utility measures). University and hospital ethics was obtained and patients were recruited and consented to participate in the RCT resulting in the assignment of 130 patients MIS hip arthroplasty procedures. Baseline patient demographics, comorbidity, quality of life, and utility were obtained for all patients. In-hospital costing data was obtained including operating room and patient room costs as well as medication, rehab and complications. Post-discharge costs were calculated from direct and indirect costs of medication, rehab, medical costs and complications until one year post-operatively. Clinical effectiveness measures were administered at intervals until one year post-operatively. Results. Patient groupings were similar pre-operatively with regards to demographic variables and quality of life measures (WOMAC, SF36, Pat5D). Post-operatively comparison of costs and complications were not different across the different surgical approaches (p>.05). Cost-effectiveness analyses (cost/QALY) were not statistically different (p>.05) when comparing the three MIS hip arthroplasty procedures. Conclusion. Primary total hip arthroplasty is a cost-effective surgical procedure and compares favorably with other health interventions. Our study is among the first to compare the cost-effectiveness of different MIS surgical approaches using contemporary methods of cost-effectiveness analyses. Our data suggests that the MIS Anterolateral approach is not superior to the MIS Posterolateral or MIS Direct Lateral approach with regards to cost-effectiveness of the intervention. Our economic evaluation was sensitive to early post-op complications including dislocation and re-operation. Surgeons should select an MIS approach based on criteria including technical preference, reliable implant placement, patient safety and complication minimization

Subcapital fractures about the hip continue to be a common clinical scenario with which we all face. There are estimated to be over 350,000 hip fractures annually in the U.S. with 40% being displaced femoral neck fractures. The mean cost is over $30,000. Optimizing surgical care is essential with the overall goal being to perform the most effective treatment with the lowest risk of reoperation that provides the best postoperative function and pain relief. In the “young” (which is often defined as whatever age is younger than you!) reduction and internal fixation is often the most effective retaining the native femoral head. The risk of non-union and AVN is often less than potential complications that can follow an arthroplasty with 40% of displaced fractures treated with ORIF eventually requiring reoperation. Essentially for every 100 patients that undergo ORIF for displaced femoral neck fracture, choosing arthroplasty instead results in 17 conversions avoided. In the “elderly” in general we treat all displaced fractures with a total hip replacement which reduced re-admissions and is more cost effective for displaced femoral neck fractures. Aside from the medical morbidity following an arthroplasty dislocation is the primary concern. We have found the anterolateral approach reduces this significantly. Non-displaced fractures that are valgus impacted and biomechanically stable are treated with cannulated screws. Perhaps it can be argued that a hemiarthroplasty (bipolar or monopolar) has a lower risk of dislocation compared to a total hip replacement if performed by a surgical team with less frequent total hip replacement experience. However, total hip replacement results in less pain and better function when the patients are independent with intact mental status (patient not the surgeon…!). My algorithm is non-displaced valgus impacted or “stable” fractures undergo cannulated screws and the displaced fractures receive a total hip arthroplasty via an anterolateral approach

There are numerous examples in medicine where “eminence trumps evidence.” The direct anterior approach (DA) is no exception. Its meteoric rise has largely been driven by industry and surgeon promotion. This surgical approach continues to garner interest, but this interest is largely for marketing purposes, as emerging data would suggest a high risk, low reward operation. In addition, factors such as selection bias and impact bias, have substantially swayed peoples interest into making an inferior operation look better. There are several factors related to the direct anterior approach that should give us pause. Those include the surgeon learning curve, limited functional benefit and increased complications. There is no question the DA approach for total hip arthroplasty (THA) has a long and steep learning curve. The majority of studies would suggest at minimum, 50–100 cases before a surgeon is comfortable with this approach and some studies would suggest the technical difficulties of this approach remain an issue even with increasing experience. This proves difficult with an attempted rapid adoption of this technique by a surgeon who may perform less than 50 THAs per year but feel the need to offer this approach to their patients for marketing purposes. One of the many touted benefits of the DA approach is the perception of improved functional outcomes. Many of the early studies showed early improvement in gait, pain and mobility. However, these studies compared the DA approach to an anterolateral approach. Even when compared to the anterolateral approach, considered the most invasive and least muscle sparing, the benefits of the DA approach were only short term (6 weeks). The majority of retrospective studies, prospective randomised studies and meta-analyses comparing DA to a posterior approach show little, if any, benefit of one approach over another with regards to functional benefit. Another touted benefit includes a low or no dislocation risk associated with the posterior approach. On the contrary many studies have failed to demonstrate lower dislocation rates with the DA approach compared to a contemporary posterior approach. A recent registry study from the Michigan Arthroplasty Registry Quality Initiative (MARQI) showed equal dislocation rates between the DA and posterior approach. Concerns have also been raised regarding unique and more frequent complications with the DA approach compared to other surgical approaches for total hip arthroplasty. Unique complications such as ankle fractures and a high incidence of nerve injury, especially damage to the lateral femoral cutaneous nerve, have been reported. In addition, the data now clearly show a higher incidence of complications on the femoral side, including early loosening and periprosthetic fracture. As responsible surgeons, if we want to say the DA approach is different, then fine, we can say it's different. Claims of superiority of one approach over another have not been born our in the literature and in fact much of the data would suggest a high risk no reward operation for the DA approach compared to other surgical approaches for total hip arthroplasty

Anterior surgical approaches for total hip arthroplasty (THA) have increased popularity due to expected faster recovery and less pain. However, the direct anterior approach (Heuter approach which has been popularised by Matta) has been associated with a higher rate of early revisions than other approaches due to femoral component loosening and fractures. It is also noted to have a long learning curve and other unique complications like anterior femoral cutaneous and femoral nerve injuries. Most surgeons performing this approach will require the use of an expensive special operating table. An alternative to the direct anterior approach is the anterior-based muscle-sparing approach. It is also known as the modified Watson-Jones approach, anterolateral muscle-sparing approach, minimally invasive anterolateral approach and the Röttinger approach. With this technique, the hip joint is approached through the muscle interval between the tensor fascia lata and the gluteal muscles, as opposed to the direct anterior approach which is between the sartorius and rectus femoris and the tensor fascia lata. This approach places the femoral nerve at less risk for injury. I perform this technique in the lateral decubitus position, but it can also be performed in the supine position. An inexpensive home-made laminated L-shaped board is clamped on end of table allowing the ipsilateral leg to extend, adduct, and externally rotate during the femoral preparation. This approach for THA has been reported to produce excellent results. One study reports a complication rate of 0.6% femoral fracture rate and 0.4% revision rate for femoral stem loosening. In a prospective randomised trial looking at the learning curve with new approach, the anterior-based muscle-sparing anterior approach had lower complications than a direct anterior approach. The complications and mean operative time with this approach are reported to be no different than a direct lateral approach. Since this surgical approach is not through an internervous interval, a concern is that this may result in a permanent functional defect as result of injury to the superior gluteal nerve. At a median follow-up of 9.3 months, a MRI study showed 42% of patients with this approach had fat replacement of the tensor fascia lata, which is thought to be irreversible. The clinical significance remains unclear, and inconsequential in my experience. A comparison MRI study showed that there was more damage and atrophy to the gluteus medius muscle with a direct lateral approach at 3 and 12 months. My anecdotal experience is that there is faster recovery and less early pain with this approach. A study of the first 57 patients I performed showed significantly less pain and faster recovery in the first six weeks in patients performed with the anterior-based muscle-sparing approach when compared to a matched cohort of THA patients performed with a direct lateral approach. From 2004 to 2017, I have performed 1308 total hip replacements with the anterior-based muscle sparing approach. Alternatively, I will use the direct lateral approach for patients with stiff hips with significant flexion and/or external rotation contractures where I anticipate difficulty with femoral exposure, osteoporotic femurs due to increased risk of intraoperative trochanteric fractures, previously operated hips with scarring or retained hardware, and Crowe III-IV dysplastic hips when there may be a need for a femoral shortening or derotational osteotomy. Complications have been very infrequent. This approach is a viable alternative to the direct anterior approach for patients desiring a fast recovery. The anterior-based muscle-sparing approach is the approach that I currently use for all outpatient total hip surgeries

The anterolateral MIS-THA approach can be divided into the Modified Watson-Jones approach (MWJ) performed in the lateral position and the Anterolateral Supine method (ALS) performed in the supine position. Femoral preparation is flexible in stem selection in the MWJ method. On the other hand, the ALS method is more stable for placement on the acetabular implant. Now we introduce novel anterolateral MIS approach named AL60, it makes use of the merits of both MWJ and ALS methods. Technique. The patient is fixed at 30 degrees on the dorsal side from lateral position. That is 60 degrees on the half side from the horizontal plane, and the platform of the operating table is removed just as in the MWJ method. During surgery, the pelvis is fixed by the posterior support, and the stability of the pelvis is very good. Also, if the inclination is accurate at 30 degrees, by holding the holder parallel to the operating table when inserting the cup, the cup is theoretically inserted at Anatomical anteversion 30 degrees. The intraoperative field of view is also visible to the assistant due to the semi-lateral position. Femoral preparation is easier than the MWJ method because the affected limbs have fallen to the dorsal side already. Discussion. Since March 2017 to the end of August 2018, the AL60 method was used for 207 primary THA. There were no dislocations or fractures and any other complications. Full weight bearing was possible from the next day. The AL60 method has stability of the ALS method for acetabular preparation and the operability of the MWJ method for femoral preparation. Therefore, it can be said that new AL60 approach method makes use of the merits of both MWJ and ALS methods

Aims. To assess the accuracy of posterior and anterolateral methods of injection into the subacromial space (SAS) of the shoulder. Patients and methods. Ethical approval was obtained and 50 patients (23 women and 27 men) with mean age of 64.5 years (42-87 years) and clinical diagnosis of subacromial impingement were recruited. Patients with old or recent shoulder fracture, bleeding disorders, and allergy to iodine were excluded. All injections were given by the consultant or an experienced registrar after obtaining informed consent. Patients were randomised into posterior and anterolateral groups and the method of injection was revealed by opening sealed envelopes just before the injection. A combination of 3mls 0.5% bupivacaine and 2mls of radiographic dye (Niopam) was injected in the subacromial space (SAS) using either anterolateral (n-22) and posterior approaches (28). AP and lateral radiographs of shoulder were taken after injection and were reported by a Consultant Radiologist blinded to the method of injection. Visual analogue scale (VAS) and Constant-Murley shoulder score was used to assess pain and function respectively. Both scores were determined before and 30 minutes after the injection. Results. 22 injections (78.5%) were accurately placed in SAS with the posterior approach and in 14 patients (63.6%) with anterolateral approach. This difference was statistically significant (P< 0.05). Only patients who received injection accurately in SAS with either method had a reduction in pain of an average of 4 points on VAS, and improvement in the Constant score of average 14 points. Conclusions. The posterior approach of SAS injection is more accurate than anterolateral approach. Injections that are correctly placed in the SAS lead to better reduction of pain and improvement in the Constant score

Larger diameter femoral heads and improved operative approaches and soft tissue repair/closure have somewhat reduced the incidence of recurrent instability after total hip arthroplasty (THA). Nevertheless, hip instability remains one of the most common reasons for reoperation after THA, and accounts for roughly a quarter of hip revisions in the United States in Medicare patients. The prevalence of instability after THA varies widely, from 0.3% to 15%. Surgeons have come to understand that hip instability can be caused by implant malposition, impingement, and inadequate soft tissue tension or integrity. While the cumulative risk of instability is acceptable at approximately 2.8% with transtrochanteric approaches, this is based upon the trochanter actually healing (and often being advanced). On the other hand, trochanteric nonunion and proximal migration have been noted by many, and this frequently results in catastrophic instability. Moreover, and importantly, abductor insufficiency is one the most difficult causes of hip instability to solve. Woo and Morrey reported a 17.6% instability rate when trochanteric nonunion occurred with 1 cm proximal trochanteric migration. Alternatively, the contemporary incidence of instability with the posterolateral or anterolateral approaches, and an adequate soft tissue repair, is approximately 1–2%

Protrusio acetabuli can be either primary or secondary. Primary or idiopathic protrusio is a rare condition of unknown etiology. Secondary protrusio may be associated with rheumatoid arthritis, ankylosing spondylitis, osteoarthritis, osteomalacia, trauma and Paget's disease. Challenges in surgery include: lack of bone stock, deficient medial support to the cup, difficulty in dislocating the femoral head, and medialization of the hip joint center. Several surgical techniques have been described: use of cement alone without bone graft; morselised impacted autograft or allograft with a cemented cup; metal cages, reinforcement rings, and solid grafts. We describe our technique of impaction grafting using autologous bone and a cementless porous-coated hemispherical cup without the use of acetabular rings or cages in patients with an average age of 46 years. Protrusion was graded depending on distance of medial wall from Kohler's line as mild (1–5 mm medial), moderate (6–15 mm medial) and severe if it was more than 15 mm medial to the Kohler's line. All patients were operated in the lateral position using a modified Hardinge's anterolateral approach. Adductor tenotomy may be required in cases of severely stiff hips. After careful dislocation of the femoral head, it was sectioned in situ into slivers to facilitate obtaining the graft. The periphery was reamed and care was taken to preserve the membrane lining the floor of the defect. Morselised graft was impacted with hemispherical impactors and the trial cup 1–2 mm larger than the last reamer placed in the desired position. The final socket was then inserted. Femoral preparation was performed in routine fashion. The mean pre-operative Harris Hip Score of 52 improved to 85 points at a mean follow up of 4 years. The average acetabular inclination angle was 42 degrees. Our results have shown incorporation of the graft in all cases. There was no evidence of progression of the protrusio or cup loosening in any of the cases. Thus far, our hips have not shown osteolytic lesions. The technique described is a satisfactory biological solution of restoring bone stock particularly in young and middle-aged patients

Introduction & aims. Correct prosthetic alignment is important to the longevity and function of a total hip replacement (THR). With the growth of 3-dimensional imaging for planning and assessment of THR, the importance of restoring, not just leg length and medial offset, but anterior offset has been raised. The change in anterior offset will be influenced by femoral anteversion, but there are also other factors that will affect the overall change after THR. Consequently, the aim of this study was to investigate the relationship between anterior offset and stem anteversion to determine the extent to which changing anteversion influences anterior offset. Method. Sixty patients received a preoperative CT scan as part of their routine planning for THR (Optimized Ortho, Sydney). All patients received a Trinity cementless shell and a cemented TaperFit stem (Corin, UK) by the senior author through an anterolateral approach. Stem anteversion was positioned intraoperatively to align with cup anteversion via a modified Ranawat test. Postoperatively, patients received a CT scan which was superimposed onto the pre-op CT scan. The difference between native and achieved stem anteversion was measured, along with the 3-dimensional change in head centre from pre-to post-op. Finally, the relationship between change in stem anteversion and change in anterior offset was investigated. Results. Mean change in anterior offset was −2.3mm (−14.0 to 7.0mm). Mean change in anteversion from native was −3.0° (−18.8° to 10.5°). There was a strong correlation between change in anterior offset and change in anteversion, with a Pearson correlation coefficient of 0.89. A 1° increase in anteversion equated to a 0.7mm increase in anterior offset. Conclusions. A change in the anteroposterior position of the femoral head is primarily affected by a change in stem anteversion, with a 1° increase in anteversion equating to a 0.7mm increase in anterior offset. The AP position of the stem in the canal, along with the flexion of the stem will also contribute. Given the well-recognised influence of leg length, medial offset and combined anteversion on restoring hip function, it seems reasonable to assume that anterior offset will also have a significant effect on the biomechanics of the replaced hip

Hip abductor deficiency (HAD) associated with hip arthroplasty can be a chronic, painful condition that can lead to abnormalities in gait and instability of the hip. HAD is often confused with trochanteric bursitis and patients are often delayed in diagnosis after protracted courses of therapy and steroid injection. A high index of suspicion is subsequently warranted. Risk factors for HAD include female gender, older age, and surgical approach. The Hardinge approach is most commonly associated with HAD because of failure of repair at the time of index surgery or subsequent late degenerative or traumatic rupture. Injury to the superior gluteal nerve at exposure can also result in HAD and is more commonly associated with anterolateral approaches. Multiple surgeries, chronic infection, and chronic inflammation from osteolysis or metal debris are also risk factors especially as they can result in bone stock deficiency and direct injury to muscle. Increased offset and/or leg length can also contribute to HAD, especially when both are present. Physical exam demonstrates abductor weakness with walking and single leg stance. There is often a palpable defect over the greater trochanter and palpation in that area usually elicits significant focal pain. Note may be made of multiple incisions. Increased leg length may be seen. Radiographs may demonstrate avulsion of the greater trochanter or significant osteolysis. Significant polyethylene wear or a metal-on-metal implant should be considered as risk factors, as well as the presence of increased offset and/or leg length. Ultrasound or MRI are helpful in confirming the diagnosis but false negatives and positive results are possible. Treatment is difficult, especially since most patients have failed conservative management before diagnosis of HAD is made. Surgical options include allograft and mesh reconstruction as well as autologous muscle transfers. Modest to good results have been reported, but reproducibility is challenging. In the case of increased offset and leg length, revision of the components to reduce offset and leg length may be considered. In the case of significant instability, abductor repair may require constrained or multi-polar liners to augment the surgical repair. HAD is a chronic problem that is difficult to diagnose and treat. Detailed informed consent appropriately setting patient expectations with a comprehensive surgical plan is required if surgery is to be considered. Be judicious when offering this surgery

Introduction. Optimal implant position is critical to hip stability after total hip arthroplasty (THA). Recent literature points out the importance of the evaluation of pelvic position to optimize cup implantation. The concept of Functional Combined Anteversion (FCA), the sum of acetabular/cup anteversion and femoral/stem neck anteversion in the horizontal plane, can be used to plan and control the setting of a THA in standing position. The main purpose of this preliminary study is to evaluate the difference between the combined anteversion before and after THA in weight-bearing standing position using EOS 3D reconstructions. A simultaneous analysis of the preoperative lumbo pelvic parameters has been performed to investigate their potential influence on the post-operative reciprocal femoro-acetabular adaptation. Material and Methods. 66 patients were enrolled (unilateral primary THAs). The same mini-invasive anterolateral approach was performed in a lateral decubitus for all cases. None of the patients had any postoperative complications. For each case, EOS full-body radiographs were performed in a standing position before and after unilateral THA. A software prototype was used to assess pelvic parameters (sacral slope, pelvic version, pelvic incidence), acetabular / cup anteversion, femoral /stem neck anteversion and combined anteversion in the patient horizontal functional plane (the frontal reference was defined as the vertical plane passing through centers of the acetabula or cups). Sub-analysis was made, grouping the sample by pelvic incidence (<55°, 55°–65°, >65°) and by pre-operative sacral slope in standing position (<35°, 35°–45°, >45°). Paired t-test was used to compare differences between preoperative and postoperative parameters within each subgroup. Statistical significance was set at p < 0.05. Results. In the full sample, mean FCA increased postoperatively by 9,3° (39,5° vs 30,2°; p<0.05). In groups with sacral slope < 35° and sacral slope > 45°, postoperative combined anteversion increased significantly by 11,7° and 12,9°, respectively. In the group with pelvic incidence > 65°, postoperative combined anteversion increased significantly by 14,4°. There was no significant change of combined anteversion in the remaining subgroups. Discussion. In this series the FCA increased after THA, particularly in patients with a low or high sacral slope on the pre-operative evaluation in standing position. This may be related to a greater difficulty for the surgeon in anticipating the postoperative standing orientation of the pelvis in these patients, as they were standardly oriented during surgery (lateral decubitus). Interestingly the combined anteversion was also increased in patients with a high pelvic incidence that is commonly associated with a high sacral slope. Conclusion. Post-operative increase of anatomical cumulative anteversion has been previously reported using anterior approach. The FCA concept based on EOS 3D reconstructions brings new informations about the reciprocal femoro-acetabular adaptation in standing position. Differences found in combined anteversion before and after the surgery show that a special interest should be given to patients with high pelvic incidence and low or high sacral slope, to optimize THA orientation in standing position

Hip resurfacing, like other orthopaedic procedures, depends for its success upon the confluence of three factors: a well-designed device, implanted using good technique, in a properly selected patient. Cleveland Clinic has had good mid-term results in more than 2,200 patients using the Birmingham device since its FDA approval in 2006. These results are quite similar to other reported series from many centers around the world. All surgery was performed using an anterolateral approach. Males accounted for 72% of the patients, and the average age was 53 years (12‐84). More than 90% of the patients had a diagnosis of osteoarthritis, and femoroacetabular impingement was the predominant pathology. The average component head size in males was 51mm, and in females 45mm. Complications were few, with no dislocations, no femoral loosening, one socket loosening, one head collapse, 2 femoral neck fractures, and 2 deep infections. There were two patients with metallosis, one due to component malposition, and one in a small, dysplastic female. There were no destructive pseudotumors. Overall survivorship at up to 8 years was more than 99%. Survivorship in young males, under age 50 with OA was 100%. New mushroom templates for head size are described. Additional imaging recommendations including a standing lateral of the pelvis, and a CT scan for femoral anteversion may be helpful in patient selection