The purpose of this study was to determine if a short femoral stem (Lima Corporate, Udine, Italy) would result in a strain distribution which mimicked the intact bone better than a traditional length stem, thereby eliminating the potential for stress-shielding. A 2 mm thick moldable plastic (PL-1, Vishay Micromeasurements, Raleigh, NC) was contoured to six fourth-generation composite femoral bones (Pacific Research Laboratories, Vashon, WA). The intact femurs were then loaded (82 kg) in a rig which simulated mid-stance single limb support phase of gait (Figure 1). During testing, the femurs were viewed and video recorded through a model 031 reflection polariscope. Observing the photoelastic coating through the polariscope, a series of fringes could be seen, which represented the difference in principal strain along the femur. The fringes were quantified using Fringe Order, N, as per the manufacturers technical notes. In order to analyze the strain distribution, the femur was separated into 6 zones, 3 lateral and 3 medial, and the maximum fringe order determined. Upon completion of testing of the intact femur, the short length femoral stem was inserted and tested, and finally the traditional length femoral stem was inserted and tested. Anterior and lateral radiographs were obtained of the femur with each femoral stem in order to confirm proper alignment.INTRODUCTION:
METHODS:
The surgical management of musculoskeletal tumours is a challenging problem, particularly in pelvic and diaphyseal tumour resection where accurate determination of bony transection points is extremely important to optimise oncologic, functional and reconstructive options. The use of computer assisted navigation in these cases could improve surgical precision. We resected musculoskeletal tumours in fifteen patients using commercially available computer navigation software (Orthomap 3D). Of the eight pelvic tumours, three underwent biological reconstruction with extra corporeal irradiation; three endoprosthetic replacement (EPR) and two required no bony reconstruction. Four diaphyseal tumours had biological reconstruction. Two patients with proximal femoral sarcoma underwent extra-articular resection and EPR. One soft tissue sarcoma of the adductor compartment involving the femur was resected with EPR. Histological examination of the resected specimens revealed tumour free margins in all cases. Post-operative radiographs and CT show resection and reconstruction as planned in all cases. Several learning points were identified related to juvenile bony anatomy and intra-operative registration. The use of computer navigation in musculoskeletal oncology allows integration of local anatomy and tumour extent to identify resection margins accurately. Furthermore, it can aid in reconstruction following tumour resection. Our experience thus far has been encouraging.
Obtaining accurate bone cuts based on mechanical axes and ligament balancing, are necessary for a successful total knee procedure. The Orthosensor Tibial Trial displays on a GUI the magnitude and location of the lateral and medial contact forces at surgery. The goal of this study was to develop the algorithms to inform the surgeon which bone cuts or soft tissue releases were necessary to achieve balancing, from an initial unbalanced state. A rig was designed for lower body specimens mounted on a standard operating table. Surgical Tests were then defined: Sag Test, leg supported at the foot; Dynamic Heel Push test, flexing to 120 degrees with the foot sliding along a rail; Varus-Valgus test; AP Drawer test; Internal-External Rotation test. The bone cuts were made using a Navigation system, to match the Triathlon PCL retaining knee. To determine the initial thickness of the tibial trial, the Sag Test was performed to reach 0 deg flexion. The Heel Push Test was then performed to check the AP position of the lateral and medial contacts, from which the rotational position of the tibial tray was determined. Pins were used to reproduce this position during the experiments. Surgical Variables were then defined, which would influence the balancing: LCL Stiffness, MCL Stiffness, Distal Femoral Cut Level, Tibial Sagittal Slope, Tibial Varus or Valgus, and AP Femoral Component Length. Balancing was defined as equal lateral and medial forces due to soft tissue tensions throughout the flexion range, equal varus and valgus stiffnesses, and no contacts closer than 10mm to component edges. All of the above tests were then performed sequentially, and the changes in the contact force readings were considered as a signature of that Surgical Variable. In an actual surgical case, having obtained readings from the Surgical Tests, the data will be compared with the signatures of the Surgical Variables. This will then identify the Variable which needed correction. The Surgical Tests will be repeated and the readings should be closer to balanced. Further correction of another Variable is carried out if necessary. In early clinical cases, it was found that this method allowed for identification of how to reach a balanced state, and achieved soft tissue balancing in a quantitative way.
The Pelvic Support Osteotomy (PSO) or Ilizarov Hip Reconstruction(IHR) is well described for the treatment of septic sequelae of infancy. The purpose of this study was to clinically, functionally and radiographically assess our short-term results of this procedure. 25 patients (16 boys, 9 girls) who had undergone a IHR using the Ilizarov/TSF construct over a period of 10 years for a variety of pathologies were reviewed. The mean age at surgery was 15 years 4 months. The pre-operative diagnoses were SCFE(10), hip sepsis (6), DDH (6) and Perthes (3). All had significant leg length discrepancies, 16 had a painful stiff hip, 6 had a painful mobile hip and 3 had a painless unstable hip. At surgery, a mean measured proximal valgus angle of 51° and a mean extension angle of 15° was achieved. Distal femoral lengthening averaged 4.2 cm and distal varus correction was a mean of 8°. The mean fixator time was 173 days. At a mean of 2 years and 7 months follow-up the lower-extremity length discrepancy had improved from a mean of 5.6 cm apparent shortening to 2.3 cm. Trendelenberg sign was eliminated in 18/25 cases. Improvements in range of hip movements and gait parameters were observed. Stance time asymmetry, step length asymmetry, pelvic dip and trunk lurch improved significantly. One patient had conversion to a total hip replacement after 7 years, 4 patients required re-do PSO due to remodelling of the proximal osteotomies, two had heterotopic ossification and two had significant knee stiffness due to lack of compliance. The early results of IHR are encouraging to equalise limb lengths, negate trendelenburg gait, provide a mobile hip with a reasonable axis and the possibility of conversion to THR in the future if needed. Complications need to be anticipated and the effects of remodelling and maintaining adequate knee range of motion must be emphasised.
The surgical management of musculoskeletal tumours is a challenging problem, particularly in pelvic and diaphyseal tumour resection where accurate determination of bony transection points is extremely important to optimise oncologic, functional and reconstructive options. The use of computer assisted navigation in these cases could improve surgical precision. We resected musculoskeletal tumours in fifteen patients using commercially available computer navigation software (Orthomap 3D).Background
Materials and methods
Tenodesis of the long head of biceps is an established technique for management of biceps pathology including tears, instability, and chronic tendinosis intractable to non-operative management. Very few studies have reported on clinical outcomes of all-arthroscopic, non-interference, biceps tenodesis techniques. The purpose of this study is to evaluate the functional and quality of life outcomes of patients treated with an all-arthroscopic biceps tenodesis with a suture anchor. Case Series Level 4 Evidence Fifty-eight (58) patients with a mean age of 58.5 years were treated with an arthroscopic biceps tenodesis in a single surgeons practice. A single suture anchor was used with a non-interference technique, either in isolation or in association with an arthroscopic rotator cuff repair. A retrospective analysis was performed on prospectively collected outcome measures on patients with a minimum one-year follow-up. Patients were evaluated with an ASES, Constant, and WORC scores pre-operatively and at 6 and 12 months post-operatively. In addition, patients were questioned post-operatively as to whether they experienced any biceps cramping, fatigue, or cosmetic deformity (popeye sign).Purpose
Method
Bony tumours of the foot account for approximately 3% of all osseous tumours. However, literature regarding os calcis and talar tumours comprises individual case reports, short case series or literature reviews with no recent large series. We retrospectively reviewed the medical notes and imaging for all patients with calcaneal or talar tumours recorded in the Scottish Bone Tumour Registry since the 1940's. Demographics, presentation, investigation, histology, management and outcome were reviewed.Introduction
Methods
Controversy exists regarding the optimal technique for arthroscopic rotator cuff repair. The purpose of this multicentre randomized double-blind controlled study was to compare the functional outcomes and healing rates of double-row suture techniques with single row repair. Patients undergoing arthroscopic rotator cuff repair were randomized to receive either a double row (DR) or single row (SR) repair. The primary objective was to compare the WORC score at 24 months. Secondary objectives included anatomical outcomes by MRI or ultrasound, the Constant, and ASES scores. A sample size calculation determined that 84 patients provided 80% power with a 50% effect size to detect a statistical difference between groups.Purpose
Method
The purpose of this study was to determine if the use of a new 4 Dimensional CT scan aids the clinician in defining the size and area of the scapular bone to be removed arthroscopically in patients with Snapping Scapular Syndrome. From January 2009 – January 2011 nine consecutive patients with Snapping Scapular Syndrome were included. In six patients, (mean age 21±5 years, range 15–27) conservative treatment failed. These patients were positioned prone and demonstrated their snapping motion during the 7 seconds duration of the scan. The 4D CT machine scans 16 cm volumes in 0.3 seconds. It also scans motion, allowing a 3D reconstruction of the scapulothoracic joint, its’ movements and the dynamic area of impingement of the scapula on the surrounding structures. This scan has already improved arthroscopic removal of the supero-medial angle of the scapula. The scan showed in one case not only snapping of the superior medial angle of the scapula on the 2nd rib, but also extra bone impinging on the 3rd rib. Another case showed no real impingement but movement of the 2nd and 3rd rib by a tethering structure and a third case demonstrated impingement of the lateral third of the clavicle on the 2nd rib. The images provided by this new 4D CT scan offer greater pre-operative insight on the pathology in each individual patient with Snapping Scapular Syndrome. Therefore, we feel that it is a valuable addition to the assessment and treatment of these patients.
Controversy exists regarding the optimal technique of subscapularis mobilization during shoulder arthroplasty. The purpose of this multicentre randomized double-blind study was to compare the functional outcomes and healing rates of the lesser tuberosity osteotomy (LTO) to the subscapularis tenotomy (ST). Patients undergoing shoulder arthroplasty were randomized to receive either a LTO or ST. The primary outcome was to compare subscapularis strength, as measured by an electronic hand-held dynamometer at 12 months. Secondary outcomes included range of motion, WOOS, Constant and ASES scores. A sample size calculation determined that 80 patients provided 80% power with a 50% effect size to detect a significant difference between groups.Purpose
Method
An open superior capsular shift is a well-established technique for the management of patients with multidirectional shoulder laxity and the absence of a Bankart lesion. Few studies have reported on functional and quality of life outcomes using arthroscopic technique for shoulder stabilization using superior capsular shift in patients with no Bankart lesion. The purpose of this study was to assess the functional and quality of life outcome scores following shoulder stabilization with a selective arthroscopic superior capsular shift with suture anchors, for treatment of multidirectional laxity and the absence of a Bankart lesion. Case Series Level 4 Evidence Thirty-six (36) patients with a mean age of 30.8 years, with a diagnosis of recurrent anterior atraumatic shoulder instability, and no Bankart lesion, were identified in a single surgeons practice. These patients underwent an arthroscopic shoulder stabilization with an anterior inferior to superior capsular shift. The labrum was arthroscopically released from the anterior/inferior glenoid and was shifted superiorly in conjunction with a capsular plication. A retrospective analysis was performed on prospectively collected outcome scores of patients who had with a minimum of 1 year of follow-up. The ASES and WOSI scores were administered pre-operatively and at 6 and 12 month follow-up. The presence of a positive post-operative apprehension sign was also recorded on follow-up.Purpose
Method
The purpose of this study was to determine the motion pattern of the Acromio-Clavicular (AC) joint in a normal shoulder with the use of the new 4 Dimensional CT scan. From April 2010 till January 2011 fourteen healthy volunteers (4 female, 10 male)(mean age 42±11 years) with no previous history of shoulder complaints participated in this study. The 4D CT machine scans motion, allowing a 3D reconstruction of the shoulder joint and its movements. Patients were positioned supine with their arm elevated 90° in the sagittal plane. During the 7 seconds duration of the scan they adducted their arm at that level and then elevated their arm upwards resisted by the gantry for 4 seconds, in this way simulating the clinical Bell-van Riet test for AC pathology. In the transverse plane the mean AC joint space measured in the neutral position is 1.8±0.5 mm. While adducting the arm the AC joint narrows 0.0±0.4 mm (with a positive value being narrowing and a negative value widening). On resisted elevation the joint space is narrowed 0.2±0.6 mm. The mean antero-posterior (AP) translation in this same plane is 0.2±2.2 mm on adduction (with a positive value being posterior translation of the clavicle and a negative value anterior translation) and 0.4±2.9 mm on resisted elevation. The new 4D CT scan demonstrates that the AC joint in a normal shoulder mainly translates in an AP direction, rather than being narrowed or widened, when the arm is adducted (with or without resisted active elevation).
Posterolateral spinal fusion using autograft in adult rabbits has been reported by many groups using the Boden model. Age in general has an adverse effect on skeletal healing; although, its role in posterolateral fusion is not well understood. This study examined the influence of animal age on spinal fusion using a standard model and experimental endpoints. We hypothesised that fusion quality and quantity would be less with increasing age. A single level posterolateral fusion between the fifth and sixth lumbar segments were performed in six-month and two-year-old New Zealand white rabbits (n=6 per group) using morcelized iliac crest autograft. All animals were sacrificed at 12 weeks following surgery. Posteroanterior Faxitron radiographs and CT scans were taken and DICOM data was analysed (MIMICS Version 12, Materialise, Belgium). Axial, sagittal, coronal and three-dimensional models were created to visualise the fusion masses. Bone mineral density (BMD) of the fusion mass was measured using a Lunar DPXL Dexa machine. An MTS Bionix testing machine was then used to assess peak load and stiffness. Sagittal and coronal plane histology was evaluated in a blinded fashion using H&E, Tetrachrome and Pentachrome stains. Assessment included overall bony response on and between the transverse processes. Radiographs and CT confirmed a more robust healing response in younger animals. Radiographic union rates decreased from 83% to 50% in the aged animals. A neo- cortex surrounding the fusion mass was observed in the younger group but absent in the aged animals. Fusion mass BMD and that of the vertebral body was decreased in the older animals (P<0.05). Tensile mechanical data revealed a 30% reduction in peak load (P=0.024) and 34% reduction in stiffness (P=0.073) in the two-year-old animals compared with the six-month-old animals. Histological evaluation demonstrated a reduction in overall biological activity in the two-year-old animals. This reduction in activity was observed in the more challenging intertransverse space as well as adjacent to the transverse processes and vertebral bodies at the decortication sites. Numerous sites of new bone formation was present in the middle of the fusion mass in the six-month-old animals while the bone graft in the two-year- old animals were less viable. Skeletal healing is complex and mediated by both local and systemic factors. This study demonstrated that ageing leads to an impaired and delayed skeletal repair. Where autograft is utilised, diminished graft osteoinductivity and reduced levels of growth factors and nutritional supply in the surrounding milieu explains our observations. The aged rabbit posterolateral spinal fusion model has not been previously described but would be a useful to evaluate new treatment modalities in a more challenging host environment.
