Proximal hamstring tendon avulsion from the ischial tuberosity is a significant injury, with surgical repair shown to have superior functional outcomes compared to non-surgical treatment. However, limited data exists regarding the optimal rehabilitation regime following surgical repair. The aim of this study was to investigate patient outcomes following repair of proximal hamstring tendon avulsions between a conservative (CR) versus an accelerated rehabilitation (AR) regimen. This prospective randomized controlled trial (RCT) randomised 50 patients undergoing proximal hamstring tendon repair to either a braced, partial weight-bearing rehabilitation regime (CR=25) or an accelerated, unbraced regime, that permitted full weight-bearing as tolerated (AR=25). Patients were evaluated pre-operatively and at 3 and 6 months post-surgery, via patient-reported outcome measures (PROMs) including the Lower Extremity Functional Scale (LEFS), Perth Hamstring Assessment Tool (PHAT) and 12-item Short Form Health Survey (SF-12). Primary analysis was per protocol and based on linear mixed models. Both groups were matched at baseline with respect to patient characteristics. All PROMs improved (p>0.05) and, while the AR group reported a significantly better Physical Component Score for the SF-12 at 3 months (p=0.022), there were no other group differences. Peak isometric hamstrings strength and peak isokinetic quadriceps and hamstrings torque symmetry were all comparable between groups (p>0.05). Three re-injuries have been observed (CR=2, AR=1). After proximal hamstring repair surgery, post-operative outcomes following an accelerated rehabilitation regimen demonstrate comparable outcomes to a traditionally conservative rehabilitation pathway, albeit demonstrating better early physical health-related quality of life scores, without an increased incidence of early re-injury.
Augmentation of meniscus repairs with fibrin clot may enhance the healing capacity. Pulling the clot into the tear with a suture ensures that it stays in position. This paper aims to assess the outcome of this technique. 52 patients over 4 years undergoing suture repair of a meniscus tear with blood clot augmentation were collected from a prospective database. Follow up included outcome scores and a questionnaire. Failure was defined as pain or further surgery secondary to meniscal pathology.Abstract
Introduction
Methods
COVID 19 led to massive disruption of elective services across Scotland. This study was designed to assess the impact on elective service that the COVID-19 pandemic had, to what extent services have been restarted and the associated risks are in doing so. This is a retrospective observational study. The primary outcomes are the number of operations completed, 30-day mortality, 30-day complication rates and nosocomial infection with COVID-19 compared to previous years. Data was collected from 4 regions across Scotland from 27th March 2020 - 26th March 2021. This was compared to the same time period the previous year. 3431 elective operations were completed in the year post-pandemic compared with 12255, demonstrating a reduction of 72%. Both groups had comparable demographics. Major joint arthroplasty saw a 72% reduction, with TKR seeing a reduction of 82%. Each of the 4 health boards were affected in a similar fashion. Nosocomial COVID-19 infection was 0.4% in the post covid group. 30 day mortality was the same at 0.1%. Total complications rose from 5.7% to 10.1% post covid. This study shows that there has been a substantial reduction in elective activity across Scotland that is disproportionate to the level of COVID-19. The risk of developing COVID-19 from elective surgery is low at 0.4%, however all complications saw a significant rise. This is likely multifactorial. This study will inform decision makers in future pandemics, that it is safe to continue elective orthopaedic surgery and of the potential impact of cessation of services.
Gram staining is used as an initial indicator of synovial joint infection but has widely varied false negative rates in the literature. Clinical decisions are often made on the basis of gram stain results, such as whether a patient requires urgent surgery, and therefore it is important to understand the tests efficacy. A retrospective review of synovial fluid aspirates in NHS Tayside for the years 2017 and 2018 was performed from the departmental microbiology database. Aspirates of large joints were included (hip, knee, shoulder, wrist, elbow, ankle). Any joints with prosthesis were excluded, including fixation metalwork. Any abscess overlying a joint that was not proven to penetrate the joint was also excluded. Initial gram stain results and formal culture results were reviewed. Final culture results were considered to be the gold standard to compare gram stain results to. 2167 samples were reviewed. Of these 1552 were excluded base on inclusion criteria. Of the remaining 615, 120 (19.5%) were culture positive. There were 33 positive gram stain results, 1 false positive and 32 true positive results. The sensitivity was 26.67% with a specificity of 99.80% (p=0.0001). The negative predictive value is 84.88% (CI 83.44% – 86.21%). These results show that gram stain tests of native joints have a low sensitivity and poor negative predictive value. This is reflected in the current literature with prosthetic joints. Based on this study caution should be used when interpreting a negative gram stain result with appropriate safety netting and follow up required alongside clinical assessment.
The number of hip fracture admissions is rising; with reduced hospital bed capacity and increasing patient numbers, care pathways must be optimised to maximise inpatient bed efficiency. There is currently significant interest in improving healthcare services across all 7 days in the United Kingdom. It is unclear whether lack of allied healthcare professional review at the weekend is detrimental to hip fracture patient care. This study aims to examine whether providing 7-day physiotherapy and occupational therapy (7DPOT) service improves outcomes for fractured neck of femur patients compared to a 5-day service (5DPOT). All patients admitted with an acute neck of femur fracture were grouped into three cohorts, depending on provision of 7DPOT services: the initial cohort received 5DPOT between December 2012 and March 2013. Seven-day physiotherapy and occupational therapy was introduced for one year from October 2014 until September 2015 (2nd cohort). The service then reverted to 5DPOT between January to June 2016 (3rd cohort). The third cohort was utilised to nullify changes in the overall service which had occurred which were not attributable to 7DPOT. Data was collected prospectively using a specially designed audit tool.Introduction
Methods
Patients with asymptomatic bacteriuria (ASB) have a significantly increased risk of both superficial wound infection and deep infection following arthroplasty. Debate continues as to whether treatment of pre-operative ASB reduces the risk of subsequent prosthetic joint infection. All arthroplasty units in Scotland were contacted by telephone and asked a standard series of questions regarding pre-operative urine testing in arthroplasty patients. A review of the literature was also performed.Introduction
Patients/Materials & Methods
The availability of seven-day NHS services for patients is currently receiving widespread national attention. Rehabilitation services including physiotherapy and occupational therapy are not routinely available at the weekend. The aim of this pilot study was to determine if seven-day rehabilitation services led to improved outcomes for hip fracture patients. All proximal femur fractures were included and formed into two cohorts. Data were collected prospectively in each cohort. Cohort one underwent standard five-day rehabilitation (n=79). Cohort two received seven-day rehabilitation (n=338). Both groups were followed up to 120 days. No significant differences were observed between the cohorts for pre-fracture place of residence, ASA score or age. Combined median length-of-stay in hospital and rehabilitation improved from 28 to 21 days (p=0.054) Combined median length of stay for patients admitted from home improved from 26 to 19 days (p=0.016). This pilot study suggests that a seven-day physiotherapy and occupational therapy service may result in decreased total length-of-stay in hospital and subsequent rehabilitation. This is a clear benefit for our patients but also for our hospitals and rehabilitation units where beds are at such a premium. A wider study across multiple institutions within NHS Scotland is now needed to investigate this further.
The K2M MESA Rail is a new implant with a unique beam-like design which provides increased rigidity compared with a standard circular rod of equivalent diameter potentially allowing greater control and maintenance of correction. The aim of this study was to review our early experience of this implant. We retrospectively reviewed the case notes and radiographs of all consecutive cases of spinal deformity correction in which at least one rail was used. All radiological measurements were made according to the Scoliosis Research Society definitions. Since June 2012 thirty-three cases of spinal deformity correction were performed using the K2M Rail system. One case was excluded as there were no pre-operative radiographs. Median age was 15 years; there were 23 females. There were 26 scoliosis cases of which two had associated Chiari malformation, three were neuromuscular, and the remainder were adolescent idiopathic cases. Six patients had kyphotic deformity secondary to Scheuermann's disease. Mean length of follow-up was 16 months. In the scoliosis cases the mean pre-operative Cobb angle of the major curve was 58.6° with a mean correction of 35.6°. The mean post-operative thoracic kyphosis was 21.1°. The median number of levels included in the correction was 13. Bilateral rails were used in four cases, the remainder had one rail on the concave side and a contralateral rod. No patients required an anterior release or staged surgery. All kyphosis cases had posterior apical corrective osteotomies. The mean pre-operative thoracic kyphosis was 75.5° with a mean correction of 31°. The median number of levels included in the correction was 11. Four patients had bilateral rails. No patients required anterior release. Complications: two patients had prominent hardware. One patient had a malpositioned screw causing nerve root irritation, which was removed. There were three superficial infections, which settled with antibiotics. There were no cases of implant breakage, screw pull-out, or loss of correction. The K2M MESA Rail is a powerful new implant design which helps to achieve and maintain satisfactory correction of complex spinal deformity, and is particularly strong at correcting kyphotic deformity. It also enables restoration of normal thoracic kyphosis, particularly in idiopathic thoracic curves, which tend to be lordosing. This may prevent thoracic flat back and potential long-term sequelae. Early results show that the system is as safe and effective as other posterior deformity correction implants on the market, however, it requires further prospective follow-up to ascertain its outcomes in the long-term.
To determine the efficacy and safety of the Magec system in early onset scoliosis (EOS). In 2011, 6 males and 2 females had Magec rods, with an average age of 8.5 years (2.9–12.7 years), 7 patients had dual rods, and 1 had single. The main cause of EOS was idiopathic scoliosis (n=6), followed by Congenital (n=1), and Syndromic (n=1). Average follow up was 19.4 months (14–26 months). 4 of these patients had their previous Paediatric Isola growing rods exchanged to Magec, and 1 patient had an exchange from single to Dual Magec rods.Aim:
Methods:
To measure truncal parameters for patients treated with growing rod systems for early onset scoliosis (EOS). 44 patients underwent growth rod surgery for EOS between 1999 and 2013 (24 females and 20 males). 27 patients had idiopathic scoliosis, 13 congenital, 3 syndromic and 1 neuromuscular. 26 patients had Paediatric Isola, 8 had Paediatric Expedium, 4 had dual growth rods with domino's and 9 each had VEPTR and MAGEC rods systems. Medical records and radiographs were analysed. Cobb angle, T1-T12 and T1-S1 length, coronal and sagittal balance, apical vertical translation (AVT), space available for the lung (SAL) and shoulder balance were measured.Aim:
Methods:
Retrospective review of growth sparing spinal instrumentation. Medical records of 30 children with spinal deformity treated were evaluated. There were 14 male and 16 female patients at an average age of 4.9 years (1-14) at the time of presentation. These included 18 idiopathic, 11 congenital and a 14 year old with delayed growth having GH treatment. All patients underwent dual growing rod construct using hook and pedicle screw instrumentation. Extensions were carried out at approximately 6 monthly intervals. Average follow up was 4.2 years (2-8.5) with an average of 7.3(3-15) extension/exchange procedures per patient. Average immediate postoperative Cobb angle was 29(15-55) from a preoperative Cobb of 68(55-100) and this was maintained to a final mean Cobb angle of 30(15-60). Average gain in T1-S1 length was 5.7(3.5-9.8) cm. Five patients had final fusion at an average age of 15.5 years. There were no infections following primary operation. Out of 249 procedures including extensions/exchange, there were 9(4.5%) episodes of deep infection in 7 patients requiring debridement. Four patients (13%) had revisions for rod breakage/screw loosening/hook pullout/junctional kyphosis and three(10%) had prominent implants.Purpose
Methods and results
To evaluate efficacy of blood conservation strategies on transfusion requirements in adult scoliosis surgery and establish a protocol for cross matching. Retrospective review of 50 consecutive adult scoliosis patients treated using anterior only(14,28%), posterior only(19,38%) or combined(17,34%) approaches. All patients were anaesthetised by the same anaesthetist implementing a standard protocol using cell salvage, controlled hypotension and antifibrinolytics. Mean age was 24.6 years. BMI was 21.9. On an average 9.5(6-15) levels were fused, with an average duration of surgery of 284.6(130-550) minutes. Antifibrinolytics were used in 31(62%) of the patients which included Aprotinin in 21(42%) and Tranexamic acid in 10(20%). Patients on antifibrinolytics had a significantly (p<0.05) lower blood loss (530ml) as compared to other patients (672ml). Mean volume of the cell saved blood re-transfused was 693.8 ml and mean postoperative HB level dropped to 10.7 g/dl(7.7-15) from a mean preoperative of 13.3 g/dl(10-17). 7(42%) with combined approaches and 3(15.8%) with posterior only approach required blood transfusion, 4/50(8%) of which required intra while 6/50(12%) required intra and postoperative transfusion. None of the patients having anterior surgery alone required blood transfusion.Purpose
Methods and Results
To assess adverse events related to XLIF approach in lumbar degenerative disease. Recently novel minimally disruptive spine procedure eXtreme lateral Interbody Fusion i.e XLIF has been developed. It is 90 (off the midline true lateral approach, which allows large graft placement, excellent disc height restoration and indirect decompression at the stenotic motion segment. We describe our experience in 28 patients. Retrospective review of records of patients undergoing surgery between July 2008- Jan 2010. Presenting complaints, number of levels performed and complications (medical, approach, or implant related) were audited. Results: 28 patients (17 female: 11 male) with median age of 47 yrs, range (38-75) formed the study group. Average stay was 4 days. All patients had MRI of lumbar spine. 2/3 rd patients had low back pain as their presenting complaint. All patients had nerve monitoring through out the procedure. There were 12 single, 15 two level and 1 three level cases (total 45 levels). 14/28 patients underwent plating at the same time. EBL was 100ml. There were 11/45 adverse events (24.4%). 6 events were approach, 4 were implant bone interface and 1 medical related. Major complication occurred in 1 patient (3.6%). 2/3 rd of patients, were better after the surgery. Almost negligible blood loss, low infection rate and short average stay seemed to work in favour of this approach. Complications are there as (with any new procedure) our results indicate, but these are manageable and less common with this technique. This did not require Ethics approval and there was no grant or industry support for the above.
We aimed to evaluate the effects of implementing blood conservation strategies on transfusion requirements in adult patients undergoing scoliosis correction surgery. We retrospectively studied 50 consecutive adult patients who underwent scoliosis correction surgery (anterior, posterior or combined) between 2003 and 2007. All patients had a standard transfusion protocol. Age, BMI, pre and post operative haemoglobin, levels fused, duration of surgery, hospital stay, anti-fibrinolytics used and blood transfused was noted. 50 patients with mean age 24.6 years and mean BMI 21.9 kg/m2 were studied. 14 patients had anterior surgery, 19 patients had posterior surgery and 17 had combined anterior and posterior procedures. Mean number of levels fused was 9.5 (6–15) and mean duration of surgery was 284.6 minutes (135–550 minutes). Antifibrinolytics were used in 31 patients (62%), Aprotinin in 21(42%) and Tranexamic acid in 10 (20%). Mean blood loss in patients who received anti fibrinolytics was 530mls while mean blood loss in the other patients was 672mls. (p<
0.05). Blood transfusion was not required in any of the patients undergoing anterior correction only while 7 patients (41%) undergoing anterior and posterior correction and 3 patients (15.8%) undergoing posterior correction only required blood transfusion. Mean volume of cell saved blood re-transfused was 693.8 mls and mean hospital stay was 9.2 days. Mean pre-op haemoglobin was 13.2 g/dl (10.4–17.4) and mean post-op haemoglobin was 10.7 g/dl (7.7–15). 4 patients (8%) required intra and post-operative blood transfusion while 6 patients (12%) required blood transfusion postoperatively. In conclusion, the use of anti-fibrinolytics like Aprotinin and Tranexamic acid reduces blood loss in scoliosis surgery. In the current scenario, with Aprotinin no longer available for use, our study would recommend the use of Tranexamic acid alongwith other blood conservation measures. In our unit we do not have blood cross matched for anterior surgery alone.
On review of the 550 other scans the average age was 51.9 years old. The incidence of SBO within this group is 10%. Only 6% of these patients were under 18. Out of these 33 patients 30.3% (10 patients) had SBO. Over 18 the incidence of SBO was only 8.5%.
This study aims to evaluate the accuracy of sheer off self limiting screw drivers and to assess repeatability with age. It has been reported that overzealous tightening of halo pins is associated with co-morbidity. Our unit has recently received a tertiary referral where the patient over tightened a pin leading to intracranial haematoma, hence our interest in this subject. The torque produced by six new and nine old screw drivers was tested using an Avery Torque Gauge and a Picotech data recorder. These devices are designed to produce a torque of 0.68 Nm, any greater than this is potentially hazardous. Accepted error for each device was +/− 10%. The average torque produced by the new screw drivers was 0.56 Nm with a range of 0.35–0.64 Nm (SD 0.120). The older screw drivers produced an average torque of 0.67 Nm ranging from 0.52–0.85 Nm (SD 0.123). In conclusion, sheer off self limiting screw drivers are not accurate devices. The older devices are more likely to produce a torque exceeding a safe range and therefore we would recommend the use of new devices only.
In a high-risk technically advanced speciality like spine surgery, detailed information about all aspects of possible complications could be frightening for the patients, and thereby increase anxiety and distress. Therefore, aim of this study was to
Analyze written evidence of the consenting procedure pertaining to (a) nature of operation (b) benefits intended as a result of the operation (c) risks specific to the particular type of operation (c) general risks of spine surgery and anaestheia. Patients’ experiences of information regarding the risk of such complications and how the information affects the patients.
The study had a non-randomized design and patients divided into TWO groups Group A and group B. The patients in the group A received standard information and were consented in a routine way without being given written proforma with all complications. The patients in the group B were given the same information as patients in the control group, with written information about common and rare complications. Patients in both groups were assessed on an ‘impact of events scale’ and hospital anxiety and depression scale immediately before ad after the consent process and again after surgery when they were discharged from the hospital. For comparison of the proportion of Yes and No answers in 2 groups, Fisher’s exact test was used, and for comparison of more than 2 groups, the Chi-square test was used. For graded answers and other ordinal scales, the Mann–Whitney U-test was used for comparison of 2 groups and the Kruskal–Wallis test for comparison of more than 2 groups. Spearman’s test was used when assessing the correlation between 2 variables measured on an ordinal scale.
In our unit we do not have blood cross matched for anterior surgery alone.
Anterior Lumbar Interbody Cages are used to recreate the lumbar lordosis in scoliosis surgery as anterior instrumentation is usually kyphogenic. We report two cases in which an anterior release was performed and interbody cages were used.In both these patients the cage was displaced anteriorly by an incorrectly positioned pedicle screw during posterior instrumentaion. In one case the cage was retrieved and correctly repositioned from the back using a TLIF approach, in the other this was noticed only post-operatively and patient needed another anterior surgery. We recommend a lateral Image Intensifier screening for combined anterior and posterior cases in which anterior cages are used in addition to posterior pedicle screws to prevent this complication.
Routine inclusion of imaging of the SI joint as part of lumbosacral spine MRI for back pain and sciatica shows only 3% positive results. SI joint should be imaged only if clinically suspected.
Paravertebral anaesthesia is a particularly effective, safe and reliable option in scoliosis patients undergoing anterior release in whom percutaneous epidural placement may be difficult to perform. A recent systematic review and meta-analysis of randomized trials has demonstrated that whilst paravertebral block and thoracic epidural insertion provide comparable pain relief after thoracic surgery, paravertebral block placement is associated with a better side effect profile, including a reduction in pulmonary complications, hypotension, nausea and vomiting and urinary retention. We describe a case of a 16 year old female patient who underwent staged correction of her thoracolumbar scoliosis. A paravertebral catheter was inserted under direct vision for continuous infusion post operative analgesia following the anterior release. 48 hours after surgery a swelling was noted in the groin, which was confirmed with ultrasonography as a fluid collection. The swelling resolved upon removing the paravertebral catheter. This suggests that it was caused by the local anaesthetic fluid tracking along the psoas muscle. Retroperitoneal infections, venous thrombosis, femoral hernia, femoral artery aneurysm and inguinal lymphadenopathy are other differentials. Ultrasonography was a fast and sensitive investigation to rule out these differentials and determined that fluid communicating with the abdominal cavity was the cause for this swelling. The infused local anaesthetic had tracked down into the femoral triangle and the swelling resolved upon cessation of the infusion.
Average age was 6.5 years(2–12). Average follow-up was 24 months (6m-36m).
Five specimens were implanted for each group 1) with pedicle screw (into L3 and L5) and tested with/without Synex (expandable) cage anteriorly, 2) implanted with a Synex cage and Double screw+rod Ventrofix system, 3) Synex cage and Double screw+ Single rod Ventrofix construct and 4) Synex cage and Single screw+ Single rod Ventrofix system.
The double screw/ single rod system is less effective than the Ventrofix System but is comparable to the pedicle screw construct. The single screw/ single rod construct leads to unacceptable movement about the axis of the inferior screw particularly in extension with a ROM much greater than the intact spine (p<
0.001)
We studied the correction achieved and the maintenance of the correction at a minimum 15 months follow up using the Paediatric USS.
Controversy exists as to whether the biomechanical properties of a 360 lumbar fusion are influenced by the order in which the anterior and posterior components of the procedure are performed. The fusion technique used Magerl screws to effect the posterior fusion and a Syncage implant (Stratec) to effect the anterior component of the fusion. Isolated motion segments from calf spines were tested in each of two groups of five. In the first group the posterior fusion was performed first and in the second group the anterior fusion was performed first. Loads were applied as a dead weight of 2Nm in each range of movement of the spine (flexion/extension, lateral flexion and rotation). The range of movement was measured using the Qualisys motion analysis software linked to a set of five cameras, using external marker clusters attached to the vertebral bodies. Each motion segment was tested prior to instrumentation, post anterior or posterior instrumentation and with both anterior and posterior instrumentation. Ranges of movement following 360 instrumentation were increased in all planes tested when posterior fixation was performed first; flexion/extension 26% v 55% (p=0.020), lateral flexion 18% v 34% (p=0.382), and rotation 18% v 73% (p=0.034). It was concluded that posterior fixation should not be performed prior to anterior fixation as this results in a significant loss of stability in both flexion/extension and rotation
Interbody fusion is increasingly widely used as a treatment for intervertebral disc disorders, but the biomechanics of the procedure are not well understood. The compressive loads through the spine are largely carried by the implant or bone graft, which typically rests on a relatively small area of the vertebral body. As the compressive strength of the bone is very low, subsidence of the implants into the vertebral bodies is a common clinical complication. Previous biomechanical studies of spinal fusion have concentrated on the stiffness of the constructs, which is important in promoting fusion. Preliminary studies have shown that there are large differences in compressive strength between different implant systems, and gave an insight into the biomechanical factors that are important in determining the strength of spinal fusion constructs. This paper reports part of a larger on going study comparing anterior and posterior fusion systems, with various methods of fixation. A major problem in interpreting the results of these tests is to distinguish between initial settling of the implants and the onset of failure to construct. We have developed a novel technique using acoustic emission monitoring to detect microcracking in the bones, which allows the onset of failure to be distinguished from initial bedding in of the implants. Two implant systems were tested, the Syncage and the Contact fusion cage. The cages were implanted into porcine lumbar spines at L4-L5, and the implanted motion segment was then dissected out. Steel plates were mounted on each end using bone cement to ensure an even distribution of load through the vertebral body. The complete constructs were then loaded in compression, using acoustic emission sensors to detect microcracking in the bones. The load was cyclically increased in o.5kN steps until failure occurred. The acoustic emission technique gave a sensitive indication of the onset of damage in the bones and allowed the initial settling of the implant under load to be identified. Using cyclic unloading and reloading, it was possible to accurately identify whether this damage had weakened the construct or increased its strength by redistributing stress concentrations. Initial results indicate that the Contact fusion cage fails at a much lower load than the Syncage in this model; this is ascribed to the very small contact areas between the cage and the vertebral body, which results in high compressive stresses in the bone. Under large compressive loads it appears that the constructs become unstable, and fail by buckling and plastic collapse of the vertebral bodies. Various failure models are therefore possible depending on which part of the vertebral body starts to collapse first.
Of the 4172 patients in a survey of all cases of tuberculosis notified in a six-month period in England and Wales in 1978-79, 198 had a bone or joint lesion; 79 were white and 108 were of Indian subcontinent (Indian, Pakistani or Bangladeshi) ethnic origin. The estimated annual notification rates for orthopaedic tuberculosis were 29 per 100 000 for the Indian subcontinent group and 0.34 per 100 000 in the white group, a ratio of 85 to 1. Rates increased with age in both groups. The spine was the most common site, and was affected in 30% of the white patients and 43% of the Indian subcontinent patients; the distribution of other sites was similar in both groups. Positive culture from a bone or joint lesion was obtained in 99 (50%) of the 198 patients (58% of white patients and 47% of the Indian subcontinent patients). Bacteriological or histological confirmation of tuberculosis either from a bone or joint lesion or from another site was obtained in 68% of the patients. Mycobacterium tuberculosis was isolated from the orthopaedic lesions in 79 of the 82 patients with identification test results and M. bovis in the 3 remaining patients. Of the 61 patients with M. tuberculosis and with no history of previous chemotherapy, 5 had resistant strains compared with 1 of the 18 patients who had previously received chemotherapy. All 6 patients with resistant strains were of Indian subcontinent ethnic origin.