Restoration Of Leg Length Research Articles

Does the utilization of fluoroscopy affect the accuracy of prosthesis position in patients undergoing hip replacement surgery via the direct anterior approach compared to the posterolateral approach for an experienced surgeon? A single-center retrospective study

BackgroundThe direct anterior approach (DAA) for total hip arthroplasty (THA) has gained popularity due to perceived advantages in achieving better early outcomes. However, the theoretical benefits such as precise implant positioning and accurate leg length restoration are still inconsistent. In this study, we compared implant position and leg length discrepancy (LLD) of the DAA and posterolateral approach (PLA) conducted by a single surgeon who had mastered both approaches.MethodsThis study retrospectively reviewed the medical records and radiographic images of 244 patients who underwent THA between 2012 and 2021 by a single experienced surgeon using either the DAA (n = 120) or PLA (n = 124). Postoperative pelvic anteroposterior radiographs at 6 months follow-up were used to assess acetabular component inclination and anteversion, as well as LLD. Mann-Whitney U tests and Chi-squared test were performed to compare outcomes between the two approaches.ResultsNo significant differences were observed in patient demographics between the two groups. The DAA group demonstrated significantly lower postoperative LLD (0.00 mm) compared to the PLA group (5.00 mm, p < 0.0001). No significant difference was observed in the Lewinnek zone for cup anteversion and inclination angles between the two groups.ConclusionsFor experienced surgeons in other approaches, our findings suggest transferring to the DAA may not substantially improve cup positioning, but it might slightly enhance limb length measurement. For surgeons already proficient in other approaches and deciding to maintain those approaches, their primary concern for optimal THA outcome should be striving for leg length equivalence.

Two-Dimensional Versus Three-Dimensional Preoperative Planning in Total Hip Arthroplasty

BackgroundPreoperative planning in total hip arthroplasty (THA) involves utilizing radiographs or advanced imaging modalities, including computerized tomography scans, for precise prediction of implant sizing and positioning. This study aimed to compare 3-dimensional (3D) versus 2-dimensional (2D) preoperative planning in primary THA with respect to key surgical metrics, including restoration of the horizontal and vertical center of rotation (COR), combined offset, and leg length. MethodsThis study included 60 patients undergoing primary THA for symptomatic hip osteoarthritis (OA), randomly allocated to either robotic arm–assisted or conventional THA. Digital 2D templating and 3D planning using the robotic software were performed for all patients. All measurements to evaluate the accuracy of templating methods were conducted on the preoperative computerized tomography scanogram, using the contralateral hip as a reference. Sensitivity analyses explored differences between 2D and 3D planning in patients who had superolateral or medial OA patterns. ResultsCompared to 2D templating, 3D templating was associated with less medialization of the horizontal COR (−1.2 versus −0.2 mm, P = .002) and more accurate restoration of the vertical COR (1.63 versus 0.3 mm, P < .001) with respect to the contralateral side. Furthermore, 3D templating was superior for planned restoration of leg length (+0.23 versus −0.74 mm, P = .019). Sensitivity analyses demonstrated that in patients who had medial OA, 3D planning resulted in less medialization of horizontal COR and less offset reduction. Conversely, in patients who had superolateral OA, there was less lateralization of horizontal COR and less offset increase using 3D planning. Additionally, 3D planning showed superior reproducibility for stem, acetabular cup sizes, and neck angle, while 2D planning often led to smaller stem and cup sizes. ConclusionsOur findings indicated higher accuracy in the planned restoration of native joint mechanics using 3D planning. Additionally, this study highlights distinct variances between the 2 planning methods across different OA pattern subtypes, offering valuable insights for clinicians employing 2D planning.

A Consecutive Series of Vancouver B2 Periprosthetic Femur Fractures Treated With Contemporary Monoblock Versus Modular Revision Stems: Clinical and Radiographic Outcomes

BackgroundTapered fluted titanium (TFT) stems are the implant design of choice for managing Vancouver B2 periprosthetic femur fractures (PFFs), producing reliable results over the past few decades. The aim of this study was to compare the radiographic and clinical outcomes of Vancouver B2 PFFs treated with contemporary monoblock versus modular TFTs. MethodsA consecutive series of 113 patients (72 women, 64%, mean age 70 years [range, 26 to 96]) who had a B2 PFF were treated with either a monoblock (n = 42) or modular (n = 71) TFT stem between 2008 and 2021. The mean body mass index was 30 ± 7. The mean follow-up was 2.9 years. A radiographic review was performed to assess leg length and offset restoration, endosteal cortical contact length, and stem subsidence. Kaplan-Meier analyses were used to determine survivorship without revision, reoperation, or dislocation. ResultsThere was no difference in the restoration of leg length (0.3 ± 8.0 mm) or offset (2.8 ± 8.2 mm) between the monoblock and modular cohorts (P > .05). Mean endosteal cortical contact length (47.2 ± 26.6 versus 46.7 ± 2 6.4 mm, P = .89) and stem subsidence (2.7 ± 3.5 versus 2.4 ± 3.2 mm, P = .66) did not differ. No difference in patient-reported outcome measures (Hip Disability and Osteoarthritis Outcome Score-Joint Replacement; Veterans RAND 12 Item Health Survey Physical and Mental; visual analog score; and Lower Extremity Activity Scale) between the groups was observed. Survivorship at 2 years free from reoperation, revision, and dislocation was 90.4, 90.3, and 97.6%, respectively, for the monoblock cohort; and 84.0, 86.9, and 90.0%, respectively, for the modular cohort. ConclusionsNo significant differences in radiographic or clinical outcomes were observed between patients treated with monoblock or modular TFTs in this large series of B2 PFFs.

Leg Length Discrepancy After Hip Fracture Repair is Associated With Reduced Gait Speed.

A negative correlation exists between functional outcomes and leg length discrepancy (LLD) following hip fracture repair. We have assessed the effects of LLD following hip fracture repair in elderly patients on 3-meter walking time, standing time, activities of daily living (ADL), and instrumental activities of daily living (IADL). One hundred sixty-nine patients enrolled in the STRIDE trial were identified with femoral neck, intertrochanteric, and subtrochanteric fractures that were treated with partial hip replacement, total hip replacement, cannulated screws, or intramedullary nail. Baseline patient characteristics recorded included age, sex, body mass index Charlson comorbidity index (CCI) score. ADL, IADL, grip strength, sit-to-stand time, 3-meter walking time and return to ambulation status were measured at 1 year after surgery. LLD was measured on final follow-up radiographs by either the sliding screw telescoping distance or the difference from a trans-ischial line to the lesser trochanters, and was analyzed as a continuous variable using regression analysis. Eighty eight patients (52%) had LLD <5mm, 55 (33%) between 5-10mm and 26 subjects (15%) >10mm. Age, sex, BMI, Charlson score, and ambulation status had no significant impact on LLD occurrence. Type of procedure and fracture type did not correlate with severity of LLD. Having a larger LLD was not found to have a significant impact on post-operative ADL (P = .60), IADL (P = .08), sit-to-stand time (P = .90), grip strength (P = .14) and return to former ambulation status (P = .60), but did have a statistically significant impact on 3-meter walking time (P = .006). LLD after hip fracture was associated with reduced gait speed but did not affect many parameters associated with recovery. Continued efforts to restore leg length after hip fracture repair are likely to be beneficial.

Does robot-assisted surgery reduce leg length discrepancy in total hip replacement? Robot-assisted posterior approach versus direct anterior approach and manual posterior approach: a propensity score-matching study

BackgroundAdvocates of robot-assisted technique argue that robots could improve leg length restoration in total hip replacement. However, there were few studies to compare the robot-assisted posterior approach (RPA) with conventional posterior approach (PA) THA and direct anterior approach (DAA) THA in LLD. This study aimed to determine whether robot-assisted techniques could significantly reduce LLD compared to manual DAA and manual PA.MethodsWe retrospectively reviewed the cohort of consecutive ONFH patients who underwent THA robot-assisted posterior, manual posterior, and manual DAA from January 2018 to December 2020 in one institution. One experienced surgeon performed all procedures. We calculated the propensity score to match similar patients in different groups by multivariate logistic regression analysis for each patient. We included confounders consisting of age at the time of surgery, sex, body mass index (BMI), and preoperative LLD. Postoperative LLD and Harris hip scores (HHS) at two years after surgery of different cohorts were compared.ResultWe analyzed 267 ONFH patients treated with RPA, DAA, or PA (73 RPA patients, 99 DAA patients, and 95 PA patients). After propensity score matching, we generated cohorts of 40 patients in DAA and RPA groups. And we found no significant difference in postoperative LLD between RPA and DAA cohorts (4.10 ± 3.50 mm vs 4.60 ± 4.14 mm, p = 0.577) in this study. The HHS at 2 years postoperatively were 87.04 ± 7.06 vs 85.33 ± 8.34 p = 0.202. After propensity score matching, we generated cohorts of 58 patients in manual PA and RPA groups. And there were significant differences in postoperative LLD between the RPA and PA cohorts. (3.98 ± 3.27 mm vs 5.38 ± 3.68 mm, p = 0.031). The HHS at 2 years postoperatively were 89.38 ± 6.81 vs 85.33 ± 8.81 p = 0.019. After propensity score matching, we generated cohorts of 75 patients in manual DAA and PA groups. And there were significant differences in postoperative LLD between the DAA and PA cohorts. (4.03 ± 3.93 mm vs 5.39 ± 3.83 mm, p = 0.031) The HHS at 2 years postoperatively were 89.71 ± 6.18 vs 86.91 ± 7.20 p = 0.012.ConclusionThis study found no significant difference in postoperative LLD between RPA and DAA, but we found a significant difference between RPA and manual PA, DAA and manual PA in ONFH patients. We found a significant advantage in leg length restoration in primary total hip arthroplasty with robot-assisted surgery.

A Video Teaching Tool Is Effective for Training Residents in Hip Arthroplasty Templating.

Work hour restrictions imposed on orthopedic surgery residents since the early 2000s have reduced educational opportunities at the workplace and encouraged alternative strategies for teaching outside the clinical setting. Preoperative templating is essential for safe and effective total hip arthroplasty (THA) and is accurate in predicting final implants. We sought to determine the effectiveness of a video tool for teaching orthopedic residents basic THA templating skills. We developed a video-based teaching tool with instructions on proper THA templating techniques. Ten cases were selected for testing, after excluding patients with severe hip deformities and poor-quality radiographsand only retaining those with concordance betweentemplating by the senior authors and implanted components. The study subjects included three postgraduate year 1 (PGY-1), three PGY-2, and three PGY-5 residents, and three adult reconstruction fellows (PGY-6). Templating skills were assessed before and after watching the instructional video. The evaluation included the size and positioning of femoral and acetabular components, as well as the restoration of leg length. Each templating session was repeated twice. Variance was measured to evaluate consistency in measurements. A linear mixed model and F-test were used for statisticalanalyses. The number of years in training significantly affected performance prior to exposure to the instructional video. Post-exposure, there was a significant improvement in the accuracy of sizing and positioning of acetabular and femoral components for PGY-1, PGY-2, and PGY-5 residents. The results achieved were comparable to PGY-6 examiners, who did not gain substantial performance benefits from the instructional video. Limb length restoration was less affected byexperience or exposure to the video. Component positioning and sizing, as well as leg lengthdiscrepancy (LLD), showed a significant decrease in variance after the intervention in all study groups. Video learning is reliable in teaching invaluable skills to orthopedic surgery residentswithout encroaching on work hours. We conceived a concise video to train orthopedic residentsto perform THA templating with proper technique and demonstrated its efficiency andreproducibility.

Resection and reconstruction of the proximal femur with revision stems: a cost-effective alternative.

Modular oncologic megaprosthesis is the standard method for reconstruction after resection of tumors of the proximal femur. These implants have been utilized for either primary tumors or metastatic disease of bone and multiple myeloma. Fixation is based on either cemented or cementless stems, and a collar supporting the body of the prosthesis. For those patients with advanced disease and/or limited life span, a judicious approach should balance the functional expectations, prognosis, and the issue of cost of the surgical procedure and the implant that is selected. Based on the principles of distal fixation of tapered stems, the authors have utilized implants originally designed for hip revision surgery to reconstruct the proximal femur in 19 patients, after resection because of metastases, multiple myeloma and some aggressive primary tumors. The essentials of the technique consist of distal fixation in the remaining isthmus of the femur by means of tapered stems, impacted in such a way to achieve solid primary fixation, balanced with accurate leg length restoration. Proximally, the implant remains devoid of bone coverage. In this retrospective study, proper distal fixation, leaving the proximal part of the implant uncovered with bone, has resulted in good functional results in mid-term follow-up of patients. Primary fixation has led to secondary bone ongrowth and remodeling, providing secondary fixation. Complications such as instability, loosening and infection are comparable with those associated to the traditional management with mega prosthesis. The utilization of tapered stems for distal fixation after proximal femoral resections has shown reliable results after mid-term follow-up. The method might be considered as a cost-effective alternative for selected patients.

Gluteus Maximus Tendon Reference: A Novel Method to Restore Leg Length in Total Hip Arthroplasty With Femoral Bone Loss

Accurate restoration of leg length and proximal femoral geometry is essential for achieving satisfactory outcomes in both primary and revision total hip arthroplasty. Although common landmarks such as the greater trochanter and the lesser trochanter (LT) may be used to measure limb length intraoperatively in primary cases, these landmarks may be absent or disrupted in fractures and revision procedures. We propose the distance between the gluteus maximus tendon gluteal sling (GS) and the center of the femoral head (FHC) as a novel anatomic landmark beyond the zone of injury, which can be used to restore limb length in the setting of proximal femoral bone loss or fracture. One hundred healthy hips were retrospectively reviewed using MRI to determine the distance between the proximal edge of the GS and the FHC. Additional measurements were collected including the distance between the GS and the greater trochanter and LT, as well as the FHC to the LT and greater trochanter.Results: The distance between the GS and the femoral head was consistent and measured 8.0 cm (±1.88 cm, SD = 0.66). A moderate positive correlation (r = 0.37, P < 0.001) was observed between patient height and GS to FHC distance. The distance between the GS and the center of the femoral head consistently measures 8 cm and can be used to set implant height to restore proximal femoral geometry and leg length in total hip arthroplasty with proximal femoral bone loss.

Hip offset and leg-length restoration in revision hip arthroplasty with a monoblock, hydroxyapatite-coated stem.

Restoration of normal hip biomechanics in arthroplasty surgery is important in order to achieve good muscle function and joint stability. In this retrospective cohort study, we examined the postoperative radiographs of 131 femoral revision arthroplasty procedures using a monoblock, fully hydroxyapatite (HA)-coated titanium stem. Femoral offset, modified-global offset and leg length were measured of the operated and contralateral hips. Femoral offset was restored to ±10 mm in 108 cases (82%), modified-global offset was restored ±10 mm in 93 cases (71%) and leg length was restored to ±10 mm in 102 cases (81%). There were 4 dislocations with a mean follow-up period of 38 months. Restoration of hip biomechanics is achievable with a monoblock stem and thus is a viable option in revision hip arthroplasty.

Robotic-assisted versus manual total hip arthroplasty in obese patients: a retrospective case–control study

AimsThe objective of this study was to evaluate the accuracy of acetabular cup positioning in the obese patients when using robotic-assisted technology during total hip arthroplasty (THA).MethodsData were retrospectively collected from patients who underwent primary (THA) with a body mass index (BMI) ≥ 28 kg/m2 and ≥ 1 year of follow-up between January 2018 and December 2019. Their demographics, diagnosis, acetabular cup positioning, American Society of Anesthesiologists (ASA) score, Harris Hip Score (HHS), and Forgotten Joint Score (FJS) at the final follow-up were recorded for analysis.ResultsThere were no statistically significant differences between the two groups in height, weight, BMI, ASA score, or preoperative Harris Hip Score (HHS). Also, there was no difference in inclination angle between the two groups (R-THA: 41.29° ± 3.04°; manual THA (M-THA): 40.47° ± 5.46°; P = 0.312). However, the mean anteversion angle was greater in the R-THA group (20.71° ± 1.98° vs. 19.08° ± 4.04°; P < 0.001). Compared to M-THA, R-THA more frequently achieved an acetabular cup angle within 5° of the target (anteversion, 98.1% vs. 78.1% P = 0.001; inclination, 88.5% vs. 53.1%, P < 0.001). The R-THA group was more advantageous in restoring the hip center of rotation (COR) and leg length difference (LLD). There was no statistical difference in postoperative HHS (P = 0.404) or FJS (P = 0.497) between the two groups.ConclusionsCompared to manual technique, robotic-assisted technique provided more precise acetabular cup positioning and better leg length restoration for obese patients. The robotic-assisted technique was more advantageous in recovering the center of rotation position and achieved a higher proportion of the acetabular cup placed in the target safety zone. Further studies are needed to confirm the clinical outcomes of surgeries in obese patients using robotic-assisted technology.

Relative Femoral Neck Lengthening in Legg-Calvé-Perthes Total Hip Arthroplasty.

BackgroundTotal hip replacement (THR) in patients with a history of Legg-Calvé-Perthes disease can be a technically challenging procedure due to the distorted hip morphology. We propose a technique in which THR is preceded by a modified relative femoral neck lengthening (RFNL) procedure. Hereby, we aim to restore the biomechanical parameters.MethodsTwenty-eight patients underwent RFNL in preparation of a second-stage THR between December 2011 and September 2019. The mean age was 38.1 ± 11.4 years. Radiographs were analyzed for centrotrochanteric distance, lateral displacement of the greater trochanter, and leg length discrepancy to assess the biomechanical restoration. Complication rate, reoperation rate, and patient-reported outcome measures were measured.ResultsMean centrotrochanteric distance increased from −18.7 ± 6.7 mm preoperatively to 1.9 ± 9.0 mm (P < .001) after RFNL and to 11.4 ± 10.4 mm after THR (P < .001). Mean lateral displacement of the greater trochanter increased from 34.2 ± 8.1 mm preoperatively to 42.4 ± 5.2 mm (P < .001) after RFNL and to 49.9 ± 8.3 mm after THR (P < .001). Leg length discrepancy decreased from 17.5 ± 10.5 mm to 2.7 ± 2.2 mm after THR (P < .001). Mean Harris Hip Score improved from 56.9 ± 17.6 preoperatively to 89.4 ± 10.7 at the latest follow-up (P < .001). Eight patients (8 hips) postponed THR because of sufficient clinical improvement, at a mean follow-up of 4.2 ± 2.1 years. Two hips needed a revision RFNL due to non-union (7.1%), and 1 hip replacement was revised due to a deep infection (5.0%).ConclusionsRFNL prior to THR in patients with end-stage osteoarthritis following Legg-Calvé-Perthes disease allows for utilizing regular implants with straight access to the femoral canal, with restored biomechanics and restoration of leg length. The prominent overhanging greater trochanter is reduced to prevent postoperative extra-articular impingement.

Effect of Vertical and Lateral Offset Restoration on Clinical Outcomes in Intracapsular and Extracapsular Hip Fractures Undergoing Hemiarthroplasty

ObjectiveWe aimed to investigate whether there is a change in the postoperative lateral and vertical femoral offset (FO) in patients who underwent bipolar straight stem hemiarthroplasty (SSHA) and calcar stem hemiarthroplasty (CRHA) and whether this change makes a difference in the comparison of both groups.Material and methodsThis study included 109 patients who met these criteria. Patients are divided into two groups according to treatment methods. There were 58 patients (group 1) who underwent SSHA due to intracapsular (AO type 31-B neck and 31-C head fracture) femur fracture, and there were 51 patients (group 2) who underwent CRHA due to extracapsular (AO type 31-A intertrochanteric) femur fracture. We analyzed femoral vertical and lateral femoral offset, Wiberg angle, and head-neck angle difference in both groups.ResultsThe median age was significantly higher in the CRHA group (p=0.042). The Harris hip score (HHS) was significantly higher in the SSHA group (p=0.023). The femoral offset difference was 5 mm in the SSHA group, while it was significantly lower (-6 mm) in the CRHA group (p<0.001). The Wiberg angle difference did not differ significantly between patient groups (p=0.214). The limb length difference was found to be similar in both surgical groups (p=0.483).ConclusionsThe study results show that there was no negative correlation between clinical and radiological outcomes in the SSHA group, whereas there was a negative correlation between clinical and radiological outcomes in the CRHA group. It is very difficult to control vertical and lateral offset reconstruction, especially in extracapsular hip fractures reconstructed by hemiarthroplasty. Deficiencies in lateral and vertical stabilization restoration may be associated with poor clinical outcomes in CRHA patients. Orthopedic surgeries should be performed carefully when restoring leg length and femoral offset, especially calcar replacement hemiarthroplasties.

Effect of the acetabular cup positioning and leg length restoration after total hip arthroplasty using robotic-assisted surgery system

Objective: To assess the improvement of the robotic-assisted total hip arthroplasty (rTHA) regarding the acetabular cup positioning and the leg length restoration. Methods: Clinical data of 246 patients undergoing primary unilateral THA from September 2019 to June 2021 in Peking University Third Hospital were retrospectively reviewed, including patients treated with rTHA (n=113) and conventional THA (cTHA) (n=133). Thirty-seven male patients along with 76 females were enrolled into the rTHA group with a mean age of (62±9) years. In comparison, the average age of cTHA group was (60±12) years with 59 males and 74 females. The postoperative inclination and anteversion of the acetabular cup and the rate of acetabular cup within the Lewinnek and Callanan "safe zone" were documented and analyzed. For the patient with normal or surgically restored contralateral hip, the leg length discrepancy was also measured and compared between the two groups. Results: The overall mean postoperative inclination and anteversion was 39.0°±5.5° and 14.1°±5.1°, respectively. No statistically significant difference was found between the rTHA and cTHA group regarding postoperative inclination (39.3°±2.9° vs 38.7°±7.0°, P=0.383) and anteversion (13.4°±4.3° vs 14.7°±5.6°, P=0.054). In rTHA group, 97.3%(110/113) of the cups were implanted within the Lewinnek"safe zone"(75.9%(101/133) in cTHA group) and 94.7%(107/113) were within the Callanan"safe zone"(66.2%(88/133) in cTHA group), and those were both higher in rTHA group (both P<0.01). There was no significant difference in postoperative leg length discrepancy between the two groups (P=0.445). Meanwhile, 29(23.0%) cases of cTHA group had leg length discrepancy more than 5 mm, and it was 9.7%(9/93) in rTHA group. Conclusion: It indicated the benefit of rTHA in acetabular cup positioning as well as the leg length restoration.

Femoral antetorsion after calcar-guided short-stem total hip arthroplasty: A cadaver study.

Calcar‐guided short stems in total hip arthroplasty (THA) permit surgeons to successfully reconstruct postoperative femoroacetabular offset, accurately restore leg length, and adequately re‐establish a wide range of caput‐collum‐diaphyseal angles. However, their effect on femoral antetorsion is less known. Indeed, controlling antetorsion of the femoral stem can be challenging because of the differences in individual femoral geometry and curvature. Therefore, we investigated if calcar‐guided short‐stem THA alters femoral antetorsion and compared it with conventional‐stem THA. Using 12 Thiel‐fixed, full‐body cadaver specimens from donors without known hip disorders, we compared an uncemented calcar‐guided femoral short‐stem prosthesis with an uncemented conventional straight‐stem prosthesis. In a paired study setup, each specimen received a calcar‐guided short stem on one side and a conventional stem on the other. On the acetabular side, all specimens received a press‐fit, monobloc acetabular cup. Femoral antetorsion angles were measured using the Waidelich method, and pre‐ and post‐operative angles of both sides were recorded. The mean preoperative femoral antetorsion angles were similar in both groups (24.8° ± 7.5° vs. 23.8° ± 6.1°, p = 0.313). Mean postoperative femoral antetorsion angles were 23.0° ± 5.5° in short‐stem and 13.5° ± 7.1° in conventional‐stem hips. Short‐stem hips had a small but nonsignificant difference in femoral antetorsion angles pre‐ and post‐operatively (1.8° ± 3.2°, p = 0.109), while the difference for conventional‐stem hips was much larger and highly significant (10.3° ± 5.8°, p < 0.001). Calcar‐guided short‐stem THA effectively restores femoral antetorsion. However, how this affects long‐term clinical outcomes and complications warrants further exploration.

KingMark's dual-marker versus a conventional single-marker templating system: is there a difference in accuracy of predicting final implant sizes and leg lengths?

Pre-operative templating for total hip replacement (THR) surgery leads to more accurate implant sizing and positioning. This study aimed to compare the KingMark™ dual-marker system for magnification calibration to the current gold standard single-marker system in accuracy of predicting implant size and restoration of leg length post-operatively. This is a retrospective analysis of patients who had primary THR surgery from 2013 to 2019 by a single surgeon. Patients were in two cohorts whose operations were completed at separate healthcare facilities. Patients in the first cohort had pre-operative templating using the KingMark system; patients in the second cohort had templating using a single-marker. For all patients, pre-operative radiographs were reviewed; predicted implants noted; and leg length discrepancies calculated. These were compared to post-operative data. We then tested the null hypothesis that there was no difference between the templating methods for prediction accuracy of implant size and achieving restoration of leg length. A total of 121 patients were included in the KingMark cohort, and 104 were included in the single-marker cohort. In the KingMark cohort, 83.5% of patients had implantation of a cup within one size of that predicted, compared to 71.2% of the single-marker cohort. This superiority was statistically significant. There was a greater proportion of exact cup size predictions in the KingMark cohort, but this was not statistically significant. We did not find any significant difference between the cohorts for stem size, or stem placement, or reduction of leg length discrepancy. We have demonstrated statistically significant superiority of the KingMark over a single-marker templating system for predicting cup size in primary THR surgery. For post-operative restoration of leg length, our study did not show any advantage of KingMark templating compared to single-marker templating.

Key performance and training parameters in primary total hip arthroplasty - an expert consensus using the Delphi technique.

Primary total hip arthroplasty (THA) is a commonly performed and successful operation which orthopaedic trainees must demonstrate competence in prior to completion of surgical training. An assessment of agreement between surgical trainers regarding the critical steps of a primary THA has never been undertaken. The aim of this study was to define and rank the key steps of a primary THA regards ease of teaching and their importance in achieving the best patient outcome. The Delphi technique with 3 iterative rounds was used to establish expert group consensus. The benchmark for consensus was set at an 80% agreement in any category for each step of a THR. The intra-class correlation coefficient (ICC) was used to report on the inter- and intra-rater reliabilities between and within participants responses respectively in rounds 2 and 3. 50 consultant orthopaedic hip surgeons completed round 2, and 28 completed round 3. Overall, 27 steps (54 parameters) were identified, with 16 parameters achieving consensus agreement for their impact on patient outcome, and 17 for ease of teaching. The inter-rater ICC for patient outcome parameters was 0.89 and 0.92 in rounds 2 and 3 respectively while for teaching parameters it was 0.82 and 0.73. 50% of surgeons agreed that acetabular reaming, assessing and accurately restoring leg length, and acetabular cup anteversion were the 3 most difficult steps to teach trainees, while 90% agreed these 3 steps were substantially important to patient outcome. Another 5 steps achieved consensus for their substantial impact on patient outcome but failed to achieve consensus for ease of teaching. The results of this expert consensus have produced a rank-order list of the key steps in primary THA, which may be used for orthopaedic curriculum development and guiding focused improvements for surgical training in primary THR including simulation.

Robotic-arm assisted THA can achieve precise cup positioning in developmental dysplasia of the hip : a case control study.

AimsThis study aimed to evaluate the accuracy of implant placement with robotic-arm assisted total hip arthroplasty (THA) in patients with developmental dysplasia of the hip (DDH).MethodsThe study analyzed a consecutive series of 69 patients who underwent robotic-arm assisted THA between September 2018 and December 2019. Of these, 30 patients had DDH and were classified according to the Crowe type. Acetabular component alignment and 3D positions were measured using pre- and postoperative CT data. The absolute differences of cup alignment and 3D position were compared between DDH and non-DDH patients. Moreover, these differences were analyzed in relation to the severity of DDH. The discrepancy of leg length and combined offset compared with contralateral hip were measured.ResultsThe mean values of absolute differences (postoperative CT-preoperative plan) were 1.7° (standard deviation (SD) 2.0) (inclination) and 2.5° (SD 2.1°) (anteversion) in DDH patients, and no significant differences were found between non-DDH and DDH patients. The mean absolute differences for 3D cup position were 1.1 mm (SD 1.0) (coronal plane) and 1.2 mm (SD 2.1) (axial plane) in DDH patients, and no significant differences were found between two groups. No significant difference was found either in cup alignment between postoperative CT and navigation record after cup screws or in the severity of DDH. Excellent restoration of leg length and combined offset were achieved in both groups.ConclusionWe demonstrated that robotic-assisted THA may achieve precise cup positioning in DDH patients, and may be useful in those with severe DDH.Cite this article: Bone Joint Res 2021;10(10):629–638.

Supine versus lateral position for total hip replacement: accuracy of biomechanical reconstruction.

Restoration of normal hip anatomy and biomechanics is a key surgical goal for success in total hip arthroplasty. The aim of this study was to evaluate the influence, if any, that patient positioning in the supine and lateral decubitus positions has in achieving this goal. A single center multi-surgeon case-matched series from a tertiary level referral center of patients undergoing primary unilateral THA for osteoarthritis between April 2018 and December 2019 was retrospectively analyzed. Patients (n = 200) were divided into two matched groups: supine (anterior approach, n = 100) and lateral decubitus (direct lateral or posterior/SuperPATH™ approaches, n = 100). Post-operative anteroposterior pelvic radiographs were analyzed using a previously validated software (SurgiMap, Nemaris Inc., USA) for parameters of reconstruction of the hip in the coronal plane; leg length discrepancy, vertical and horizontal displacement of the center of rotation, femoral offset, and total offset. Mean absolute leg length discrepancy in the supine group was 0.6 ± 3.3mm (95% [CI] -0.1 to 1.2mm) versus 2.4 ± 3.8mm (95% [CI] 1.6 to 3.1) in the lateral decubitus position (p < 0.001). The center of rotation was displaced medially by a mean of 3.2 ± 2.7mm in the supine group versus 1.3 ± 4.0mm in the lateral decubitus group (p < 0.001). For a surgical target of reconstructing both leg length and total offset within 5mm of native anatomy, the supine group was more than twice as likely to achieve these goals with fewer outliers (OR 2.631, 95% [CI] 1.901-3.643) (76% v 30%, p < 0.001). Total hip arthroplasty through the anterior approach in the supine position is more consistent and accurate for the restoration of leg length and total offset. Further study is required to assess how this translates with outcome. III-retrospective cohort study.

Comparing Postoperative Leg Length Discrepancy and Femoral Offset Using Two Different Surgical Approaches for Hemiarthroplasty of the Hip.

INTRODUCTIONThe direct anterior approach (DAA) and anterolateral approach (ALA) may be used for hip hemiarthroplasty (HHA) as a treatment for femoral neck fractures. The DAA often utilizes intraoperative fluoroscopy to determine leg length and offset, while the ALA traditionally utilizes an intraoperative clinical exam to determine offset and leg length. This study will evaluate two techniques: the “grid fluoroscopy [GF] technique” and the “intraoperative exam [IE] technique,” each performed by one of two separate surgeons, and compare each technique’s accuracy to restore leg length and femoral offset in a patient population that underwent HHA.METHODSTwo investigators retrospectively reviewed charts of 208 randomly selected patients who had an HHA from either a DAA or ALA performed by two different surgeons for the treatment of femoral neck fractures. Postoperative AP pelvis radiographs were measured to determine offset and leg length compared with the non-operative extremity. Non-normal continuous variables were provided by median and interquartile range. Data were analyzed with the Mann-Whitney U test and Student’s t-test.RESULTSAfter inclusion and exclusion criteria, data were reviewed on 173 hemiarthroplasties. The mean age was 80.3 years (± 11.2 years). Of the surgical patients, 65.9% were female, and 70.9% identified their ethnicity as white. The DAA was used in 93 patients and ALA in 80 patients. Analysis comparing the two techniques demonstrated no statistically significant differences in median leg length between GF technique (1.02 IQR -0.1, 2.0 mm) and IE technique (1.25 IQR -2.4, 1.3 mm,) (p=0.67). There was also no statistically significant difference in offset between GF technique (1.3 IQR 0.2, 2.1 mm) and IE technique (0.6 IQR -2.7 mm, 3.2 mm) (p=0.13). However, a difference was found in mean length of surgery that was statistically significant. We found that the mean length of surgery for the IE technique was 74.8 ± 24.7 minutes versus the GF technique, which was 95.1 ± 23.0 minutes, (p<0.0001).DISCUSSIONThere was no significant difference between leg length and offset with the use of intraoperative fluoroscopy with DAA compared to no intraoperative imaging with ALA. Our study suggests that DAA and ALA are equally effective approaches for re-establishing symmetric leg length and offset in HHA for femoral neck fractures. In this study, the ALA had a shorter surgical time compared to DAA, potentially due to the utilization of intraoperative fluoroscopy for this particular technique during the DAA.

CORR Insights®: The External Obturator Footprint Is a Usable, Accurate, and Reliable Landmark for Stem Depth in Direct Anterior THA.

CORR Insights®: The External Obturator Footprint Is a Usable, Accurate, and Reliable Landmark for Stem Depth in Direct Anterior THA.