The Hip & Knee Clinic at Olympic Park is dedicated to advancement of orthopaedic research. It carries out this mission through education in research, dissemination of research knowledge, advocacy for increasing of resources for research, and increasing awareness of the importance and impact of such research on orthopaedic patients and the public.
The Hip & Knee Clinic at Olympic Park welcomes applications from interested surgeons to apply to complete a fellowship at the clinic.
Bruce Warwick, Higgs Robin J E D, Munidasa Duminda, Hunjan Jaspal S, Van der Wall Hans
Clin Nucl Med 01/08/2002; 8 (27) :547-9
Acute osteochondral injuries of the hip are rare in the absence of associated dislocation. A series of cases is presented in which these injuries were sustained after relatively minor trauma to the hip. Radiologic studies revealed evidence of mild hip dysplasia and, in one case, an osteochondral fracture of the right femoral head. Scintigraphy revealed the fracture and unexpected uptake in the acetabulum, which was subsequently confirmed as being due to labral tears or acetabular osteochondral injuries. In addition, the scan showed evidence of a possible avulsion-type injury of the iliofemoral ligament, suggesting the mechanism of subluxation.
Rosa Richard A, Bert Jack M, Bruce Warwick, Gross Michael, Carroll Mike, Hartdegen Vernon
J Bone Joint Surg Am 01/01/2002
Walsh William R, Stephens Paul, Vizesi Frank, Bruce Warwick, Huckle James, Yu Yan
Arthroscopy 01/02/2007; 2 (23) :197-204
This study reports the mechanical and histologic properties of intra-articular tendon-bone healing with the application of low-intensity pulsed ultrasound (LIPUS) in an ovine knee model.
A single digital extensor tendon autograft from the right hoof was used as the graft in 89 adult sheep. Femoral fixation was achieved with an EndoButton (Smith & Nephew Endoscopy, Andover, MA) and tibial fixation by tying over a bony post. LIPUS treatment was performed daily for 20 minutes over the femoral and tibial tunnels until sacrifice in all groups, apart from the 26-week group, which was treated only for the first 12 weeks. Histology was performed at 3, 6, 12, and 26 weeks. Mechanical testing was performed at 6, 12, and 26 weeks.
The LIPUS-treated group showed increased cellular activity at the tendon-bone interface and general improvement in tendon-bone integration and vascularity. Stiffness and peak load were greater compared with the control group at 26 weeks after surgery (P < .05).
The application of LIPUS appears to improve healing at the tendon-bone interface for soft tissue grafts fixed with a suspensory fixation technique. Histology supports a benefit based on increased integration between tendon and bone and a biologically more active interface, which would account for the improved mechanical properties.
The indications of LIPUS may be expanded to include tendon-bone healing, for example, in anterior cruciate ligament reconstruction.
Bruce Warwick, Van Der Wall Hans, Storey Geoffrey, Loneragan Robert, Pitsis George, Kannangara Siri
Clin Nucl Med 01/08/2004; 8 (29) :465-8
Acetabular labral tears are an increasingly recognized cause of hip pain in young adults with hip dysplasia and older patients with degenerative disease of the hips.
The authors analyzed retrospectively bone scintigraphy in 27 patients with acetabular labral tears diagnosed by MRI/arthroscopy. Analysis was also made of scintigraphy in 30 patients without labral tears being investigated for other causes of hip pain for comparison.
Patients with labral tears had hyperemia of the superior or superomedial aspect of the acetabulum and increased delayed uptake in either a focal superior pattern or in an "eyebrow" pattern of a superomedial tear. This pattern was not seen in any other sources of hip pathology.
Uptake in the superior or superomedial aspect of the acetabular rim is characteristic of a labral tear. Absence of this pattern carries a high negative predictive value for the diagnosis.
Bruce Warwick, Van der Wall Hans, Peters Matthew, Morgan Lucy, Hian Liaw Yong, Storey Geoffrey
ANZ J Surg 01/09/2004; 9 (74) :723-6
Respiratory complications are common after arthroplasty with fat emboli and thromboembolic disease (PTE) being the most serious. As fat embolism from bone marrow should contain reticuloendothelial cells, we hypothesized that these cells take up colloid in the lung. A prospective tomographic study of 99m Tc phytate and perfusion was performed within 24 h after arthroplasty.
Tomographic lung studies were acquired after 99m Tc phytate and 99m Tc MAA injection. Pre- and postoperative arterial blood gases (ABG), radiography/computed tomography were obtained. ABG were analysed as the difference in alveolar-arterial oxygen gradients, pre- and postoperatively (D(A-a)).
Forty patients were studied, 16 with hip and 24 with knee arthroplasties. Lung uptake of 99m Tc phytate was present in 35% of cases. PTE was detected in 25 of 38 (67%) patients evaluated. D(A-a) was significantly different between patients with PTE/fat embolism and without either entity (P < 0.05).
A simple test is available for the detection of fat embolism in the lungs. It can specifically differentiate this common cause of hypoxia from PTE.
Deakin Mark, Stubbs David, Bruce Warwick, Goldberg Jerome, Gillies Ronald M, Walsh William R
Arthroscopy 01/12/2005; 12 (21) :1447-51
To assess the effect of suture material, anchor orientation, and anchor eyelet design on the static loading properties of suture anchors.
TYPE OF STUDY:
Biomechanical bench study.
Two metallic suture anchors, Mitek GII (Mitek, Westwood, MA) and Corkscrew (Arthrex, Naples, FL) and a bioabsorbable anchor (Biocorkscrew; Arthrex) were tested with single strand of No. 2 Ethibond (Ethicon, Norderstedt, Germany) or No. 2 FiberWire (Arthrex) suture. Suture pull angle was varied through 0 degrees, 45 degrees, and 90 degrees with the anchor rotation angle in either a sagittal or coronal plane. Constructs were tested to failure using an MTS 858 Bionix testing machine (Material Testing Systems, Eden Prairie, MN). Peak loads, stiffness, energy to peak load, and failure modes were determined for all samples.
FiberWire showed superior static mechanical properties when compared with single-strand Ethibond over all testing conditions (P < .05). Suture pull angle had a significant effect on load to failure with both metallic anchors but not on the bioabsorbable anchor (P < .05).
Suture pull angle and anchor rotation angle play an important role in the failure load of suture when placed in an eyelet. The polyaxial nature of the Biocorkscrew eyelet allows for increased degrees of freedom but introduces failure of the suture eyelet as a new failure mode.
The loading direction and placement of the suture anchor plays a role in the performance of the suture anchor-suture complex.
Walsh William R, Langdown Andrew J, Auld Jason W, Stephens Paul, Yu Yan, Vizesi Frank, Bruce Warwick J M, Pounder Neill
J. Biomed. Mater. Res. Part B Appl. Biomater. 01/07/2008; 1 (86) :74-81
A 1.5 cm unilateral rabbit ulna defect model was performed in 18 adult NZ white rabbits. The defects were filled with a beta-tricalcium phosphate bone graft substitute (JAX TCP). The surgical site in half the animals was treated daily with 20 min of low intensity pulsed ultrasound (LIPUS). Animals were sacrificed at 4 weeks (n = 3 per group) or 12 weeks (n = 6 per group) following surgery for radiographic and histologic endpoints. Radiography revealed some resorption of the JAX TCP by 12 weeks in the control and LIPUS treated groups. LIPUS treatment did not accelerate this resorption. Some new bone formation was noted in the control groups at the defect margins while little bone formed in the center of the defect at 4 and 12 weeks. In contrast, radiographs revealed more new bone at 4 and 12 weeks in the LIPUS treated animals throughout the section. Bone mineral density (DEXA) revealed a statistically significant difference at 4 weeks with LIPUS while no differences were found at 12 weeks. Histology of the LIPUS treated sections demonstrated new woven bone formation on and between the JAX TCP bone graft substitute particles across the defect. VEGF expression was increased with LIPUS treatment at 4 weeks and remained elevated at 12 weeks compared with controls. CBFA-1 expression levels were elevated with LIPUS treatment at both time points. LIPUS treatment increased bone formation in ulna defect healing with a beta-tricalcium phosphate bone graft substitute.
Walsh William R, Cotton Nick J, Stephens Paul, Brunelle John E, Langdown Andy, Auld Jason, Vizesi Frank, Bruce Warwick
Arthroscopy 01/07/2007; 7 (23) :757-65, 765.e1-2
The purpose of this study was to compare polylactide carbonate (PLC) interference screws with poly-L-lactide (PLLA) screws in an ovine anterior cruciate ligament reconstruction model.
A PLC screw or PLLA screw was placed in the center of a 4-strand soft-tissue autograft fixating the graft within the tibial tunnel. Assessments were made at 6 and 12 weeks for fixation strength and at time points of 6, 12, 26, and 52 weeks via computed tomography and histology.
No adverse or inflammatory reactions were noted for either material at any time point. Mechanical fixation strength increased from 6 to 12 weeks for both the PLC and PLLA screws, with no significant differences in fixation strength being found between the 2 groups. By 26 weeks, the PLC screw was partially replaced by new bone, a process that was completed by 52 weeks. The PLLA screws were intact and surrounded by a fibrous layer at 52 weeks with no obvious resorption. New bone formation within the tendon construct located in the bone tunnel proximal to the interference screw was also noted in the PLC screw group but was not observed in the PLLA group.
This study has supported the hypothesis that this bioabsorbable composite has sufficient mechanical properties and strength retention to function successfully as an interference screw but also stimulates a biologic healing response, enabling replacement by bone and tunnel healing.
This study shows both the satisfactory mechanical characteristics and osteoconductive nature of PLC used in an interference screw in an ovine anterior cruciate ligament reconstruction model.
Walsh William R, Vizesi Frank, Michael Dean, Auld Jason, Langdown Andy, Oliver Rema, Yu Yan, Irie Hiroyuki, Bruce Warwick
Biomaterials 01/01/2008; 3 (29) :266-71
The use of artificial bone graft substitutes has increased as the surgical applications widen and the availability of allograft bone decreases. The ideal graft substitute should reabsorb with time to allow and encourage new bone formation whilst maintaining its properties as an osteoconductive scaffold until it is no longer required. A potential disadvantage of some synthetic substitutes is their long dissolution time. Beta-tricalcium phosphates (beta-TCPs) have some advantages when compared to hydroxyapatite (HA), when used as a filler, in that it is more rapidly reabsorbed. Three commercially available and clinically used beta-TCP bone graft substitutes with the same chemistry (Vitoss, Osferion, Chronos) but with varying macro and microscopic characteristics were investigated using a bilateral tibial metaphyseal defect model in New Zealand white rabbits. When placed into tibial defects all three materials performed similarly in terms of mechanical properties of the healing defects. A decrease in properties was found at 12 weeks where implant resorption was nearly achieved while remodelling of the anteromedial cortex had yet to be completed. All materials were osteoconductive and supported new bone formation while implant resorption with time differed between materials. Vitoss resorbed faster than the other materials and is likely to differences in particle geometry, pore structure and interconnectivity.
Biant Leela C, Bruce Warwick J M, van der Wall Hans, Walsh William R
J Arthroplasty 01/02/2010; 2 (25) :334.e11-6
Metal-on-metal articulations are increasingly used in total hip arthroplasty. Patients can be sensitive to metal ions produced by the articulation and present with pain or early loosening. Infection must be excluded. Correct diagnosis before revision surgery is crucial to implant selection and operation planning. There is no practical guide in the literature on how to differentiate between allergy and infection in a painful total hip arthroplasty. We present the history, clinical findings and hip scores, radiology, serology, hip arthroscopy and aspirate results, labeled white cell scan, revision-hip findings, histology and clinical results of a typical patient with a hypersensitivity response to a metal-on-metal hip articulation, and how results differ from patients with an infected implant. A practical scheme to investigate patients with a possible hypersensitivity response to an implant is presented.
Shiramizu Kei, Vizesi Frank, Bruce Warwick, Herrmann Sebastian, Walsh William R
Int Orthop 01/04/2009; 2 (33) :403-6
The tibiofemoral articulating interfaces of six high flexion knee designs were examined using a standard testing protocol developed by Harris et al. [J Biomech 32:951-958 (1999)] to investigate the polyethylene insert contact areas and pressures. A load of 3600 N was applied for 10 s at 0, 30, 60, 90, 110, 135 and 155 degrees of flexion. Contact areas and pressures at the femoral-polyethylene insert interface were measured with a I-scan 4000 system. Up to 110 degrees of flexion, the VANGUARD RP HI-FLEX showed the highest contact area and lowest pressure. At the deep flexion angles, contact area decreased and contact pressure increased significantly in all knees. The NexGen series showed a constant contact area throughout the various flexion angles. In general, all high flexion knees could result in almost point contact in an extremely high range of motion.
Evans Richard O N, Goldberg Jerome A, Bruce Warwick J M, Walsh William
J Shoulder Elbow Surg 2004; 5 (13) :573-5
Goldberg Jerome A, Bruce Warwick J M, Walsh William, Sonnabend David H
ANZ J Surg 01/10/2003; 10 (73) :797-9
Diagnostic ultrasound examination has become the most commonly used investigation in Australia for diagnosing rotator cuff tears. The authors felt that the results of such investigations were often inaccurate in their clinical practices.
The diagnostic ultrasound findings in 336 cases were compared to arthrography, and in 225 cases findings at surgery.
A very poor accuracy rate of 0.38 was found for diagnostic ultrasound examination. The sensitivity was 0.24 and specificity was 0.61.
Extreme caution is recommended in the use of diagnostic ultrasound, as currently practised in a general community setting, in diagnosing full-thickness rotator cuff tears.
Langdown Andrew J, Low Adrian K, Auld Jason W, Bruce Warwick J M, Walker Peter M S
Ann R Coll Surg Engl 01/11/2005; 6 (87) :473-4
Full Text of this article is available as a PDF (296K).
Walker P, Harris I, Leicester A
J Pediatr Orthop 1998; 1 (18) :129-31
Patellofemoral problems are common in skeletally immature patients. In the evaluation of this condition, it is important to determine the position of the patella on lateral radiographs. There are no normal values to determine this ratio (patellar tendon-to-patella ratio). In this study, 225 anteroposterior (AP) and lateral radiographs of skeletally immature knees were examined and bone ages determined. The patellar tendon-to-patella ratio was then calculated for each age group until skeletal maturity. These ratios allow a more accurate assessment of patella alta in the pediatric population, assisting in diagnosis and surgical planning.
Nicklin S, Waller C, Walker P, Chung W K, Walsh W R
Am J Sports Med 2000; 6 (28) :790-3
In an effort to increase strength in hamstring tendon grafts for anterior cruciate ligament reconstruction, braiding or weaving of the tendons has been suggested. The purpose of this study was to examine the biomechanical properties of two braiding techniques compared with a four-stranded tendon graft using a sheep model. Digital extensor tendons from 5 adult sheep were harvested in 28 matched pairs and randomly allocated to French plait or four-stranded weave. The grafts were tested in a hydraulic testing machine with the tendons secured in brass grips frozen with liquid carbon dioxide. The tendons were preconditioned to a distraction of 1 mm for 10 cycles followed by testing to failure at 50 mm/sec, with a data acquisition rate of 1,000 Hz. The stiffness, ultimate load to failure, and the mode of failure were recorded. All braided samples failed at the midsubstance, while the four-stranded controls failed at the grip interface. There was a significant reduction in strength and stiffness of the braided samples compared with the controls. This study demonstrated that braiding decreases the strength and stiffness of a four-stranded tendon graft by up to 54% and 85%, respectively. This finding is supported by the work of Hearle et al. (1969), who demonstrated that the decrease in strength of fiber bundles is equal to the square of the cosine of the twist angle. The twist angle in our samples was approximately 45 degrees, which equates to a decrease in strength of 50%.
Mohammed K D, Sonnabend D H, Goldberg J A, Hutabarat S, Walker P, Walsh W R
Am J Sports Med 1998; 6 (26) :831-5
The objective of this study was to develop a method to evaluate the biomechanical performance of Bankart repairs in a human cadaveric shoulder in a clinically relevant orientation. Twenty fresh-frozen human cadaveric shoulder girdles were used to compare the biomechanical performance of intact anteroinferior capsulolabral complexes with the biomechanical performance of three Bankart lesion reconstruction techniques. Repairs were performed on surgically created Bankart lesions. Evaluations were performed with the shoulders in glenohumeral abduction and external rotation. The repair techniques employed interosseous sutures, Mitek GII suture anchors, or Acufex T-Fix devices. The suture material used in all repairs was No. 2 Ti-Cron. The biomechanical performance of the three reconstruction techniques did not differ, but each was significantly inferior compared with that of the intact shoulder samples. The interosseous repairs failed by suture pullout through soft tissue. Repairs in the Mitek GII group failed by pullout of the suture anchors, suture breakage, or pullout of the suture through soft tissue. Repairs in the T-Fix group failed by pullout of the suture through soft tissue or failure of the polymer portion of the T-Fix suture.
Biant L C, Bruce W J M, Assini J B, Walker P M, Walsh W R
J Bone Joint Surg Br 01/04/2008; 4 (90) :430-5
This prospective study presents the ten-year (5 to 16) clinical and radiological results of 55 primary total hip replacements (THR) using a cementless modular femoral component (S-ROM). All patients had a significant anatomical abnormality which rendered the primary THR difficult. The mean Harris hip score was 36 (12 to 72) pre-operatively, 83 (44 to 100) at five years, and 85 (45 to 99) at ten years. The Western Ontario and McMaster Universities osteoarthritis index (WOMAC) and short-form (SF)-12 scores were recorded from the year 2000. The mean SF-12 score at five years after surgery was 45.24 (22.74 to 56.58) for the physical component and 54.14 (29.20 to 66.61) for the mental component. By ten years the SF-12 scores were 42.86 (21.59 to 58.95) and 51.03 (33.78 to 61.40), respectively. The mean WOMAC score at five years post-operatively was 25 (0 to 59), and at ten years was 27 (2 to 70). No femoral components were radiologically loose, although five had osteolysis in Gruen zone 1, three had osteolysis in zone 7, and two showed osteolysis in both zones 1 and 7. No osteolysis was observed around or distal to the prosthetic sleeve. No femoral components were revised, although three hips underwent an acetabular revision and two required a liner exchange. At a mean of ten years' follow-up the S-ROM femoral component implanted for an anatomically difficult primary THR has excellent clinical and radiological results.
Biant Leela C, Yeoh Kwan, Walker Peter M, Bruce Warwick J M, Walsh William R
Knee 01/06/2008; 3 (15) :238-41
Many studies have shown that computer navigation in total knee arthroplasty aids the surgeon to place the prosthesis in a more accurate overall alignment. Bony resection creates the flexion and extension gaps; important in balancing the knee and implant selection in TKR. The computer plans the bone cuts but has variables that it cannot control: the surgeon, the saw blade thickness and oscillation, the accuracy of the jigs, movement of the pins, and the quality of initial mapping data inputted by the surgeon. The accuracy of computer navigated bone resections are validated on cadavers, but this is the first study to compare the predicted bone cuts to that physically resected during TKR. For 89 patients undergoing primary TKR, the bone cut from the distal femur and proximal tibia was measured using Vernier callipers and compared to the computer calculation of the same. Results show that computer measurement of the physical space left by the resected bone is accurate.
Langdown Andrew J, Tsai Nicholas, Auld Jason, Walsh William R, Walker Peter, Bruce Warwick J M
J Arthroplasty 01/04/2006; 3 (21) :381-4
We have prospectively recorded ambient operating theater temperature from 186 total knee arthroplasties and the time taken for the cement to set at implantation. The majority of cases used Antibiotic Simplex cement (n = 131), and the rest, Simplex with tobramycin (n = 55). Set time was defined as when a no. 15 scalpel could not indent the cement surface at either the femoral or tibial interface. There was a reasonable negative correlation between temperature and setting time (Antibiotic Simplex: Pearson correlation coefficient, R = -0.674; Simplex with tobramycin: R = -0.655). There was also a considerable variation of setting time at any given theater temperature. There is an inverse relationship between ambient theater temperature and the setting time for Simplex cement, and surgeons should be aware that the setting time can vary considerably. Their operative protocol should take this into account.
Bruce Warwick, Lee Tack Shin, Sundarajan Vijaya, Walker Peter, Magnussen John, Van der Wall Hans
Knee 01/08/2004; 4 (11) :303-6
Ultrasound of the musculoskeletal system is an attractive imaging modality due to the lack of ionising radiation, cost and ease of availability. A role has been established in the shoulder and pediatric hip but not in the knee. Ultrasound studies of the knee performed at six general radiological practices without established musculoskeletal expertise were compared with clinical examination in 56 patients. Final diagnoses were established by arthroscopy and/or MRI. The sensitivity and specificity for detection of superficial lesions in the knee were 88 and 41% for clinical examination and 32 and 59% for ultrasound. For deep lesions sensitivity and specificity were 61 and 64% for clinical examination and 13 and 100% for ultrasound. Ultrasound studies of the knee in a general radiological practice do not offer significant information above clinical examination.
Walker Peter, Kannangara Siri, Bruce Warwick J M, Michael Dean, Van der Wall H
Clin Orthop Relat Res. 2007 Apr; 457:144-9.
Lateral hip pain is a common complaint in patients with a history of lower back pain from spinal disease. These patients often are diagnosed and treated for trochanteric bursitis because of localized pain and tenderness in the lateral hip. We presumed numerous scintigraphic features could provide diagnostic criteria for diagnosing gluteus medius tendinitis and trochanteric bursitis. A study was designed to assess the scintigraphic criteria for diagnosis of trochanteric bursitis and to evaluate the relationship of trochanteric bursitis to gluteus medius tendinitis and lumbar degenerative disease in predicting relapse after injection. We evaluated 97 patients with greater trochanteric pain syndrome to find a correlation between trochanteric bursitis, gluteus medius tendinitis, and spinal degenerative disease using scintigraphy and magnetic resonance imaging. We also evaluated predictors for responding to trochanteric injection of local anesthetic/glucocorticoid injection. We found a correlation between lumbar degenerative disease, gluteus medius tendinopathy, and trochanteric bursitis. Of these, 30 of 48 patients (63%) responded to injection of local anesthetic and glucocorticoids. The major predictor of relapse of pain after injection in 18 patients was the presence of moderate to severe lumbar degenerative disease seen on scintigraphic imaging. We propose a mechanistic model of the greater trochanteric pain syndrome to explain the interrelationship and response to therapy. Scintigraphy can provide sensitive and specific diagnoses of gluteus medius tendinitis and trochanteric bursitis.
Harris Ian, Walker Peter M, Trieu Lawrence
ANZ J Surg 01/05/2002; 5 (72) :349-51
Ionizing radiation from intraoperative fluoroscopy presents a serious occupational health and safety concern to orthopaedic surgeons.The long-term effects of ionizing radiation are well known; they include damage to the eyes, increased risk of haematological malignancy and carcinomas throughout the body. We studied the effect of using an attachable laser aiming guide on radiation exposure during intraoperative fluoroscopy.
A prospective, randomized controlled trial was performed at a single institution. Eight hundred and eighty consecutive orthopaedic procedures involving fluoroscopy were randomized into two groups. One group had fluoroscopy without an aiming guide, the other group had fluoroscopy with the aiming guide. Total exposure time, number of exposures and the body region examined were recorded.
For most regions studied, no significant difference in exposure time or number of exposures was found. For hip fractures, use of the laser aiming device was associated with an increase in the number of exposures (P = 0.035), but there was no significant difference in average exposure time (P = 0.31). Use of the aiming device was associated with an increased number of exposures (P = 0.0025) and an increased exposure time (P = 0.0016)for examination of the wrist, but this may represent selection bias. Conclusion: Use of a laser aiming device during intraoperative fluoroscopy was not associated with decreased exposure to radiation.
Biant Leela C, Bruce Warwick J M, Assini Joseph B, Walker Peter M, Walsh William R
J Arthroplasty. 2009 Jan;24(1):27-32. Epub 2008 Nov 5.
We report the average 10-year clinical and radiographic results of 28 hips with Crowe III or IV developmental dysplasia of the hip (DDH) and a technically difficult primary hip arthroplasty using the cementless modular S-ROM stem (DePuy Orthopedics, Warsaw, Ind). Twenty-one patients required significant autologous bone grafting, 1 had a large allograft, and 6 patients required femoral shortening at the time of their total hip arthroplasty. Three patients had an intraoperative technical complication. The average preoperative Harris hip score was 37; at 10 years, 81. The Short Form 12 was 41.64 physical/54.03 mental at 10 years, and the WOMAC average score was 23 at 10 years. None of the S-ROM stems had been revised or were loose at latest follow-up. Six hips had osteolysis in Gruen zones 1 or 7 but none around or distal to the sleeve. The 10-year results of the S-ROM stem used in patients with osteoarthritis secondary to severe DDH are excellent.