Previous reports have shown the efficacy of muscle interposition grafts in treating recalcitrant infection in the presence of hip arthroplasty. We report our experience with a two stage debridement and rectus femoris pedicled interposition graft technique in chronic severe native hip infection with a persistent draining sinus. During the last 16 months, three paraplegic patients presented with persistently draining sinuses and chronic osteomyelitis of the pelvis, acetabulum and proximal femur, in a total of four hips. The mean patient age was 49 years (range, 40 to 59 years). In all patients there had been previous attempts to control the infection with wound debridement and long-term antibiotics. A two-stage operative treatment was used in all patients. The first stage comprised wound debridement, washout, gentamycin-bead application and temporary vacuum assisted wound coverage. At the second stage, approximately ten days later, through a standard anterior midline incision, the rectus femoris muscle was elevated on its pedicle, rolled, transposed into the acetabulum and sutured to the transverse acetabular ligament. At the second stage, all patients had local administration of antibiotics with genetamycin impregnated absorbable collagen fleece and all wounds were closed by delayed primary closure with a negative pressure dressing placed over the closed wound. All patients were commenced on a 6 week course of intravenous antibiotics, according to sensitivities. No loss of flap occurred in any of the patients. One wound had partial dehiscence and required a split skin graft. At the final follow-up examination all the wounds were healed and there was no recurrence of draining sinuses, pressure sores or systemic sepsis. The two stage technique with a pedicled rectus femoris interposition graft may be a useful technique for the treatment of complex chronic persistent osteomyelitis of the pelvis, acetabulum and proximal femur, with the primary aim of stopping the discharging sinus

Purpose. Rectus femoris avulsion (RFA) injuries in paediatric patients are currently managed conservatively. However, the proximal attachment of the rectus femoris muscle lies in a critical zone in the hip joint with attachments to the anterior hip capsule and anterior inferior iliac spine. Violent avulsions therefore could cause damage to the adjacent acetabular labrum and articular cartilage initiating a process leading to early degenerative changes in the hip. To date, the association between rectus avulsions and labral tears has not been studied. Method. The complete medical records of patients who were presented to McMaster University Medical Center with rectus femoris avulsions between 1983 and 2008 who were between the ages of 2 and 18 were identified. Patients were included if they had documented plain radiographs and magnetic resonance arthrography images of their hip. MRIs were reviewed by an independent musculoskeletal radiologist blinded from the history of the patients. Results. 16 patients were identified in the database with rectus femoris avulsions diagnosed on plain radiograph and 7 were included in the study with documented MRIs. The average age of patients was 13 (Range 7–16). All injuries occurred during sports activity with 43% occurred during running, 29% with kicking during soccer and during skating acceleration while playing hockey. One patient had a concurrent sartorius avulsion. All patients with rectus femoris avulsions had labral tears identified on MRI in the zone adjacent to rectus insertion. All patients were treated conservatively. Clinical records suggested 72% of patients were still limping and 86% were experiencing residual pain at last follow-up. Conclusion. Patients with rectus femoris avulsions may be at risk for concurrent traumatic labral tears. These patients should be assessed for labral pathology including a clinical examination and MRI arthrography. Level of Evidence: Level IV

BACKGROUND. Our modified procedure for rotational acetabular osteotomy (RAO) aimed to reduce operative invasion of soft tissue and to minimize incision length. SURGICAL TECHNIQUE. A shortened skin incision (10–15 cm versus 20–30 cm in traditional RAO) is curved over greater trochanter and exposed by transtrochanteric approach. Medial gluteus muscle is retracted to expose the ilium without detachment from iliac crest. Similarly the rectus femoris muscle tendon was retracted, not excised, from the anterior inferior iliac spine. The lateral part of the osteotomized ilium is cut in lunate and trapezoid shape to form the bone graft instead of the outer cortical bone of the ilium. PATIENTS. We performed RAO on 66 patients (75 hips) using this modified procedure between 2000 and 2009. Follow-up rate was 95% (71/75 hips). Of 71 hips, 28 had early-stage, and 43 had advanced-stage osteoarthritis. Mean patient age was 39.7 years at time of surgery. Mean length of follow-up was 5.3 years. Clinical assessment was performed using the Merle d'Aubigne & Postel scores. Radiographically, the lateral center-edge (CE) angle, the Sharp angle and acetabular head index (AHI) were evaluated pre- and post-operatively. RESULTS. Mean CE angle, Sharp angle and AHI improved pre- to post-operatively from −1.3 degrees to 36.5 degrees (p<0.00001), 50.3 degrees to 39.4 degrees (p<0.00001), 54.0 % to 95.7 % (p<0.00001), respectively. Clinical hip scores at latest follow-up were significantly improved. No progression of osteoarthritis was seen in hips with early-stage osteoarthritis. Ten hips with advanced-stage osteoarthritis preoperatively had radiographic evidence of progression of osteoarthritis, and six of those were converted to total hip arthroplasty. Complications included two transient lateral femoral cutaneous nerve palsies and ectopic bone formation in 15 hips, one of which required excision 1.5 years post-RAO. Kaplan-Meier survivorship analysis, with decreased clinical scores from pre-operatively and radiographic signs of progression of osteoarthritis as the end point, predicted a 10-year survival rate of 100% for early-stage osteoarthritis hips and 72.1 % for advanced-stage osteoarthritis. CONCLUSIONS. Less invasive surgical procedure for RAO preserved function of hip abductor muscle and did not adversely influence on clinical or radiographic outcome

INTRODUCTION:. The popularity of the direct anterior approach (DAA) for total hip arthroplasty (THA) is increasing as this approach causes less soft tissue damage and no muscular detachments and significantly shorter postoperative recovery time. Despite the promising early results the complication rate in the DAA cases has been concerning such as 9% rate in 247 DAA cases reported by Woolen et. al [1]. As DAA has not conventionally being used by surgeons these complications are expected to be reduced when the surgeons are more experienced. Therefore to better understand the issues that cause the postop complications in DAA we have conducted the present study. OBJECTIVES:. The objective of the current study is to investigate the postop complications in individuals with arthritic hips treated by DAA THA over a period of 3.5 years by a one surgeon. METHODS:. The procedure was performed with the patient supine on a fracture table via DAA [2]. Briefly, the approach consisted of making a 8–10 cm incision 2 cm distal and lateral to the anterior superior iliac spine to a point several centimeters anterior to the greater trochanter. The dissection advanced to visualize the anterior capsule at the interval between the tensor and the sartorius and rectus femoris muscles. The neck was osteotomized at a pre-determined level through pre-operative templating. The acetabular component was prepared through sequential reaming followed by proper exposure for preparation of the femur, with sequential increasing size broaches used until a tight proximal fit was obtained with rotational stability. Hip stability with trial components was assessed by externally rotating the hip using the fracture table along with intra-operative radiographs. All post-operative clinic notes were reviewed retrospectively for any type of complication at any follow-up visit following primary THA. Intraoperative data and complications were collected prospectively. RESULTS:. 709 consecutive patients underwent primary hip arthroplasty from 8/2007 to 12/2010 via DDA performed by a single surgeon. The overall major complication rate was 2.81% (19/709). Overall revision rate due to any cause was 1.83% (13/709). Wound related complications were 6.67% which included any type of drainage noted during post op clinic visits, wound dehiscence, stitch abscesses, or superficial infections requiring irrigation and debridement. CONCLUSION:. The lack of familiarity with the DAA in THA has prevented widespread adoption of the method. Our overall major complication rate was in the lower end of the range that is published complication rates (range of 1.36% >15.79%). The location of the incision is in an area where large skin folds and the moist skin make healing difficult. This may result in higher infections. Therefore a preoperative protocol to sterilize the sections near the inguinal area has been implemented to reduce wound related complications. Future studies should be conducted to evaluate the learning curve in different surgeons who perform THA using DAA

Biomechanical considerations are relevant to cup positioning in total hip replacement (THR) to optimise the patient-specific post-operative outcome. One goal is to place the hip centre of rotation (COR) such that parameters characterising the biomechanics of the hip joint lie within physiological ranges. Different biomechanical models have been developed and are based on exact knowledge about muscle insertion points whose positions can be estimated on the basis of bony landmarks. Therefore, accurate landmark localisation is necessary to obtain reliable and comparable parameter values. As most biomechanical considerations are limited to the frontal plane, landmark localisation relying on standardised pre-operative radiographs has been established in clinical practice. One potential drawback of this approach is that user-interactive landmark localisation in radiographs might be more error-prone and subjective than localisation in 3D images. Therefore, we investigated the possibility of increasing the reproducibility of interactive landmark localisation by providing 3D localisation techniques. As the so-called BLB score based on Blumentritt's biomechanical hip model has already been introduced into clinical practice as a criterion for cup position planning, we examined the anatomical landmarks involved in BLB score evaluation. We developed a CT-based simulation tool allowing for the generation of 3D bone surface models and standardised digitally reconstructed radiographs (DRRs). Correspondences between points in the 2D DRR and rays in the 3D bone surface model are automatically established and optionally visualised by the tool. Two modes of landmark localisation were examined: In the 2D-mode, only AP DRRs were displayed, and the users had to localise the landmarks by clicking within the DRR image. In the 3D-mode, additionally the arbitrarily rotatable bone surface models together with the aforementioned 2D/3D correspondences were visualised. The user could then choose between landmark localisation by clicking either within the DRR image or within the 3D view. In either case, the 2D landmark positions within the DRR were recorded. The participants were given both an example AP pelvis radiograph with highlighted anatomical landmarks and the following landmark descriptions from the user's manual (v2.06) of the mediCAD software (Hectec GmbH, Landshut, Germany): P4: ca. 3cm distal lesser trochanter minor (in the imagined direction of pull of the rectus femoris muscle towards the medial upper edge of the patella); P5:lateral, most proximal edge of the trochanter major; P6: most cranial edge of the sclerotic area; P7:spina iliaca anterior inferior; P8/P9:most lateral/cranial point of the wing of the ilium. (P1 and P2 are only needed to define the position of the mid-sagittal plane, and P3 is the pre-operative COR. Due to correct radiograph standardisation, we assumed this plane and P3 to be known prior to landmark localisation.). Thirteen surgeons repeated the experiments on four hips (CT datasets of two male patients). The following results were obtained (SD of relevant coordinates obtained with 2D localisation vs. SD of those obtained with 3D localisation) in the first patient (left hip: 1L; right hip: 1R) and the second patient (left hip: 2L; right hip: 2R):P4: 6.3 vs. 9.0 (1L); 6.7 vs. 5.6 (1R); 9.0 vs. 11.1 (2L); 7.1 vs. 8.6 (2R); P5: 4.4 vs. 2.8 (1L); 3.1 vs. 3.1 (1R); 4.3 vs. 2.4 (2L); 4.7 vs. 4.1 (2R); P6: 4.8 vs. 3.8 (1L); 2.9 vs. 2.8 (1R); 3.7 vs. 5.2 (2L); 6.9 vs. 3.5 (2R); P7: 12.2 vs. 6.1 (1L); 12.1 vs. 3.7 (1R); 7.6 vs. 4.6 (2L); 6.2 vs. 4.5 (2R); P8: 1.2 vs. 2.8 (1L); 2.0 vs. 2.6 (1R); 1.5 vs. 2.1 (2L); 2.0 vs. 1.6 (2R);P8: 4.1 vs. 2.1 (1L); 7.3 vs. 3.9 (1R); 1.6 vs. 2.6 (2L); 4.1 vs. 3.2 (2R). The greatest differences in reproducibility were observed in P7, which was barely distinguishable in the radiographs and, hence, showed very low reproducibility only for the 2D-mode. P4 showed low reproducibility in both modes due to its vague description and the relatively small portions of the femurs contained in the CT-scanned volume. In P9 the low reproducibility obtained with the 2D-mode might be partly explained by truncation artefacts present in the DRRs. Although our study needs to be extended to more datasets, we conclude that the availability of 3D data allows for higher landmark localisation reproducibility when compared with the conventional X-ray-based approach, which has additional drawbacks: Standardisation of X-ray imaging, which is necessary to retain comparability of biomechanical parameter values determined in different patients, is hard to achieve; specifications e.g. concerning the central beam may be met only after acquiring several radiographs. Moreover, once a 2D target cup position is defined based on the 2D biomechanical analyses, the transfer of this position into the 3D surgical site is difficult without additional 3D imaging. Hence, the use of 3D imaging and 3D landmark localisation techniques seems more promising for cup positioning based on biomechanical models, which, however, need validation

Introduction. Quadriceps weakness, which is often reported following total knee arthroplasty (TKA), affects patients' abilities to perform activities of daily living [1]. Implant design features, particularly of the patella-femoral joint, influence the mechanical advantage of the extensor mechanism. This study quantifies the changes in extensor mechanism moment arms due to different patellar resurfacing options during TKA. Methods. Posterior-stabilized TKR surgery was performed on seven cadaveric knees which were subsequently mounted in the Kansas Knee Simulator (KKS) [2]. A dynamic physiological squat was simulated between 5° and 80° knee flexion at 50% body weight while knee kinematics, including the lines of action of the rectus femoris (RF) muscle and patellar tendon (PT), were recorded using an optical tracking system. The simulation was performed after three patella treatment options: 1) leaving the native patella Unresurfaced, 2) resurfaced with a medialized Dome patella, and 3) resurfaced with a medialized Anatomic patella which included a conforming lateral facet. Moment arms from the tibio-femoral helical axis to the line of action of the PT and the RF were calculated for each patella condition. Results. The quadriceps moment arm for the Anatomic patella is smaller than the Dome during extension (Fig. 1A). Past 55° the Anatomic moment arm becomes larger than the dome. Patellar tendon moment arm for Anatomic is bigger than the dome in extension (0–50°) but smaller in flexion (50–80°) (Fig. 1B). The overall shape of the Unresurfaced patella moment arm through flexion, for both the patellar tendon and the quadriceps, was more similar to the Anatomic than the Dome although the difference in magnitude was not consistent between the six knees. Discussion. The orientations of both the RF and PT lines of action, which were used to determine the moment arm, were correlated with patellofemoral kinematics. A more extended position of the patella resulted in an increase of the PT while decreased the RF moment arm. This explains the difference between the Anatomic and dome moment arms for both PT and RF since the Anatomic patella was more extended between 0–60° knee flexion (Fig. 1C). The similarity in the PT and RF moment arms shape between the Anatomic and the Unresurfaced resurfaced was due to the similarity in their conforming geometry. The less conforming geometry of the Dome patella made it less constrained and allowed the forces applied by the RF and PT to have a greater influence on patellofemoral kinematics and moment arms than Anatomic and Unresurfaced patellae. The small changes in PT and RF moment arm observed in this study can result in large effect on muscle loads that are required to perform more strenuous activities. Multiple methodologies have been reported in literature to calculate moment arm. Future work will examine the effects of different methodologies on moment arm calculations as well as validation of results by examining the change in quadriceps moment arm required to perform certain activities