The phenomenon of twisted growth: humeral torsion in dominant arms of high performance tennis players.

This manuscript is driven by the need to understand the fundamental mechanisms that cause twisted bone growth and shoulder pain in high performance tennis players. Our ultimate goal is to predict bone mass density in the humerus through computational analysis. The underlying study spans a unique four level complete analysis consisting of a high-speed video analysis, a musculoskeletal analysis, a finite element based density growth analysis and an X-ray based bone mass density analysis. For high performance tennis players, critical loads are postulated to occur during the serve. From high-speed video analyses, the serve phases of maximum external shoulder rotation and ball impact are identified as most critical loading situations for the humerus. The corresponding posts from the video analysis are reproduced with a musculoskeletal analysis tool to determine muscle attachment points, muscle force vectors and overall forces of relevant muscle groups. Collective representative muscle forces of the deltoid, latissimus dorsi, pectoralis major and triceps are then applied as external loads in a fully 3D finite element analysis. A problem specific nonlinear finite element based density analysis tool is developed to predict functional adaptation over time. The density profiles in response to the identified critical muscle forces during serve are qualitatively compared to X-ray based bone mass density analyses.

Congruent spinopelvic alignment on standing lateral radiographs of adult volunteers.

STUDY DESIGN AND OBJECTIVES: Radiographs of 75 healthy volunteers were measured to decide parameters and ranges for "congruent" sagittal spinopelvic alignments using the pelvic radius technique. A subset of 30 of the volunteers subsequently had a second radiograph to assess for changes in the repeated measurements. SUMMARY OF BACKGROUND DATA: Measurement of spinal alignment is important. Radiographic parameters for "congruent" spinopelvic balance over the hips and changes in sagittal spinal alignments over time have not been defined. Measurement techniques for spinal alignments and to quantitate pelvic morphology need to be standardized. METHODS: The 75 volunteers (44 men/31 women, mean age 39 years, range, 20 to 63 years) had 36-inch standing lateral radiographs of the thoracolumbar spine and pelvis taken that included both hips. Thirty volunteers (19 men/11 women) had a second radiograph taken 5 to 6 years later. Radiographic measurements were made using the pelvic radius technique. This required locating a midpoint between the approximate centers of both femoral heads to establish a pelvic hip axis. A line between the hip axis and the posterior superior corner of S1 for the pelvic radius was drawn and measured for length. Angles were measured from the pelvic radius to tangents along the vertebral endplates on the 105 films with an electronic digital readout device. These angles included PR-S1 for pelvic morphology and PR-T12 for total lumbopelvic lordosis. A pelvic angle was measured from a vertical line through the hip axis to the pelvic radius. This angle gave the sagittal alignment for the pelvis over the hips. Longitudinal measurements between radiographs were compared for minimum and maximum change. Significant statistical correlations for the measurements were carefully studied to determine potentially important clinical relationships. In addition, thoracic kyphosis/lumbar lordosis ratios were assessed. RESULTS: The most constant measurement with the least change on the repeated radiographs was that for pelvic morphology (PR-S1 angle) followed by length of the pelvic radius, pelvic alignment over the hips (pelvic angle), and total lumbopelvic (PR-T12) and lumbosacral (T12-S1) lordosis. Other longitudinal measurements, including those for thoracic kyphosis and spinal balance by a plumbline, showed greater change. Measurements for pelvic morphology by the pelvic radius technique were correlative with standing total lumbosacral lordosis, regional lumbopelvic lordosis, pelvic alignment, pelvic radius length, and gender (P< or = 0.006 for each). The correlations between total and regional lumbopelvic lordosis and pelvic alignment measurements were even higher(P<0.0001). Of possible clinical importance was the finding that standard measurements for lordosis were dependent on individual pelvic morphology quantitated by the pelvic radius technique. CONCLUSIONS: In all of the sagittally balanced subjects studied, "congruent" spinopelvic alignment on all 105 standing lateral radiographs could be defined by four parameters using the pelvic radius technique: total lumbopelvic lordosis (PR-T12), incorporating complementary angles for lumbosacral lordosis (T12-S1), and pelvic morphology (PR-S1 angle) that summarily were always between -69 degrees to -116 degrees (+/-3 degrees ); centered pelvic alignment over the hips, as determined by the pelvic angle, that was always between -3 degrees to -32 degrees (+/-2 degrees ); compensated spinal balance, with a sagittal plumbline from the center of the T4 body always posterior to the hip axis as well as the center of the L4 vertebral body; and a concordant T4-T12 kyphosis/PR-T12 lordosis ratio that was always negative and between 0.15 to 0.75. [Key words: congruent alignment, pelvic radius technique, pelvic morphology, lumbopelvic lordosis, lumbosacral lordosis]

Lumbopelvic lordosis and pelvic balance on repeated standing lateral radiographs of adult volunteers and untreated patients with constant low back pain.

STUDY DESIGN: Twenty volunteers and 20 patients with no prior spine surgery had two standing lateral radiographs taken, on the average, 66 months apart and 2 weeks apart, respectively. OBJECTIVES: To first determine the reliability of the measurement techniques used, and then the longitudinal variation between radiographs for the sagittal spinopelvic alignments measured in two stable populations, the one manifesting no back symptoms (volunteers) and the other showing no changes in symptoms (patients). Pelvic morphology also was assessed quantitatively, and significant correlations for the measurements were studied. SUMMARY OF BACKGROUND DATA: There are no published studies on longitudinal variation for measurements of sagittal spinal alignments in asymptomatic control subjects or untreated patients with stable back problems. It may be helpful to know not only how much variation in alignments can be expected between radiographs of the same individual, but also which measurements and measurement techniques offer the greatest clinical reliability and application. METHODS: Each patient in this study reported mechanical type low back pain that was constant in location and character as well as clinically consistent with symptomatic degenerative lumbar disc disease. Each patient and volunteer had 36-inch-long lateral radiographs taken of the entire thoracic and lumbar spine, which included the pelvis. After intervening periods of 1 to 4 weeks (patients) and 5 to 6 years (volunteers), a second radiograph was taken for comparison. Two observers made 24 different measurements on the radiographs including determinations for lumbopelvic lordosis, pelvic balance, and pelvic morphology using the pelvic radius technique. Reliabilities, longitudinal variations, and correlations for the measurements were compared. RESULTS: The most reliable measurements were for pelvic morphology, pelvic balance, and regional lumbopelvic lordosis by the pelvic radius technique. Pelvic morphology was the most constant measurement between individual radiographs. Pelvic morphology and total lumbosacral lordosis were dependent measurements that were complementary in determining total lumbopelvic lordosis. Lumbopelvic lordosis and pelvic balance also had strong correlation, whereas lumbosacral lordosis and pelvic balance were independent measurements. CONCLUSIONS: The pelvic radius technique is recommended for evaluating lordosis to the pelvis because this approach provided not only good measurement reliability on standing radiographs for lumbopelvic lordosis, but also determination of pelvic balance over the hips and the option to assess pelvic morphology quantitatively. Lumbopelvic lordosis and pelvic balance were strongly correlative. This finding, along with higher reliability and lower longitudinal variation on repeated radiographs, indicated greater clinical application for these specific measurements.

Compensatory spinopelvic balance over the hip axis and better reliability in measuring lordosis to the pelvic radius on standing lateral radiographs of adult volunteers and patients.

STUDY DESIGN: Sagittal alignments, including lumbar lordosis and spinopelvic balance (measured from C7, S1, and hip axis reference points for the relative positions of the spine and sacropelvis over the hips), were studied on standing 36-in. lateral radiographs of adult volunteers (control subjects) and patients who had specific spinal disorders. OBJECTIVES: To determine the most reliable methods for measuring lumbopelvic lordosis and to define significant spinopelvic compensations for sagittal balance. SUMMARY OF BACKGROUND DATA: Measurements for standing sagittal balance, obtained using a C7 plumb line, and segmental angulations of the spinal vertebrae, including lordosis to the sacrum, have been reported. Absolute values, even for normative data, have had wide variation and limited clinical usefulness. Correlations of sagittal balance with the reported spinopelvic angulations (spinal vertebral and sacropelvic angulations) have not been well defined. In addition, determinates of balance (spinal and pelvic) have not been studied for reliability, and compensatory mechanisms for maintenance of balance have not been carefully evaluated. Better recognition of the correlations and more reliable methods to measure lordosis and balance and the spinopelvic compensations for its maintenance may be beneficial in treating patients who have spinal disorders. METHODS: Measurements on standing 36-in. lateral radiographs were made for sagittal alignments in adult volunteers (n = 50) and in adult patients who had symptomatic degenerative lumbar disc disease (n = 50), low grade L5-S1 isthmic (lytic) spondylolisthesis (n = 30), and idiopathic or degenerative scoliosis (n = 30). All participants exhibited clinical compensation for balance. Data were analyzed for significant correlations within each group to determine compensatory correlations of spinopelvic balance with the other sagittal alignments. Intraobserver and interobserver reliability for the parameters evaluated were calculated. This included two methods for determining lordosis (S1 end-plate and pelvic radius techniques). RESULTS: Plumb line measurements for balance from the S1 and hip axis reference points, as defined, were similar in all four groups. However, the groups appeared to adjust for balance by using common and distinctive spinopelvic compensations that resulted in significantly and characteristically different angular alignments among the four groups. Lordosis and balance measurements were closely correlated, and the correlation was characterized by pelvic rotation and translation around the hip axis. The subjects with less lordosis typically stood with the C7 plumb line anterior to and at a longer distance from the sacral reference point. This was primarily because of posterior sacropelvic translation around the hip axis and not because the sagittal plumb line initially moved anteriorly away from the sacrum. This was true in all four groups and gave the appearance that the sacropelvis was less well balanced over the hips in the subjects with less lordosis. Even small differences in lordosis appeared to be associated with considerable adjustments in the other spinopelvic alignments. Therefore, it was important to determine that lordosis was lumbopelvic more reliably measured by the pelvic radius technique. CONCLUSIONS: Lower lumbar lordosis, by the pelvic radius technique, and compensatory sacropelvic translation around a hip axis, in addition to measurements from this axis to the C7 plumb line, were the primary determinates and most reliable radiographic assessments for sagittal balance. Understanding the common and characteristically different compensations that occur with balance in these patients who had specific spinal disorders may help to improve their care.

The effect of operative position on lumbar lordosis. A radiographic study of patients under anesthesia in the prone and 90-90 positions.

STUDY DESIGN: The effect of intraoperative positioning on lumbar lordosis was retrospectively studied by radiographic analysis of 40 patients under general anesthesia. OBJECTIVES: The aim of this study was to document changes in segmental and total lumbar lordosis between preoperative standing and intraoperative radiographs taken in the "90-90" and prone positions. SUMMARY OF BACKGROUND: Preservation of physiologic lordosis was an important consideration in reconstructive lumbar spine surgery. To avoid iatrogenic loss of lordosis when using spinal instrumentation and to facilitate decompressive procedures, it was necessary to understand how segmental alignments were affected by intraoperative positioning. Although many positioning techniques were used, the effect on lumbar lordosis was not well established. METHODS: Preoperative (standing 36" lateral spine) and intraoperative radiographs (lateral lumbar spine L1 to the sacrum) in either the "90-90" position on a Hastings frame (n = 20) or the prone position on a Jackson table (n = 20) were measured twice by two independent observers using Cobb methodology for total and segmental lordosis between L1 and S1. Data were analyzed for intra- and interobserver reliability and changes in segmental and total lordosis between standing and intraoperative radiographs. RESULTS: Analysis of intra- and interobserver reliability revealed measurements were accurate and reproducible. The "90-90" position produced significant loss (P < or = 0.01) of total and segmental lordosis at all levels except L1-L2, which showed no change. Segmental lordosis was reduced nearly 60% at L2-L3, L3-L4, and L4-L5, and total lordosis was reduced by more than 35%. The prone position on the Jackson table increased segmental lordosis at L5-S1 by 22% (P < or = 0.01) and preserved total and segmental standing lordosis at all other levels. CONCLUSIONS: The "90-90" position on the Hastings frame was associated with significant reduction of total and segmental lordosis in the middle and lower lumbar spine. Positioning prone on a Jackson table maintained standing lumbar lordosis and increased lumbosacral lordosis.

Radiographic analysis of sagittal plane alignment and balance in standing volunteers and patients with low back pain matched for age, sex, and size. A prospective controlled clinical study.

STUDY DESIGN: A global and segmental study on standing lateral radiographs of 100 volunteers and 100 patients who had low back pain was undertaken to further define sagittal plane alignment and balance. The volunteer control group and the patient group were matched for age, sex, and size. METHODS: Measurements and determinations made on the standing radiographs included the following: segmental and total lordosis L1-S1 (Cobb method); thoracic kyphosis; thoracic apex; plumbline dropped from the center of C7; and sacral inclination measured between the plumbline and a line drawn along the back of the proximal sacrum. RESULTS: Segmental lordoses were significantly different between each motion segment in both groups. Approximately two-thirds of total lordosis occurred at the bottom two discs, i.e., L4-5 and L5-S1. Total lordosis was significantly less in the patients and was not age- or sex-related in either group. Patients tended to stand with less distal segmental lordosis, but more proximal lumbar lordosis, a more vertical sacrum and, therefore, more hip extension. This may be related to compensation as C7 sagittal plumb lines were comparable in both groups. Both groups had similar thoracic kyphosis. A much higher percentage of smokers was found in the low back pain patient population studied. Because of the significant amount of angulation in the lower lumbar spine, measurement of lordosis should include the L5-S1 motion segment and be done standing to better assess balance. Sacral inclination is a determinate of both standing pelvic rotation and hip extension. It is strongly correlated with segmental and total lordosis in both volunteers and patients. CONCLUSIONS: Definitions of sagittal balance are provided as well as additional sagittal plane data by which to compare corrections and fusions for different spinal disorders.

The iliac buttress. A computed tomographic study of sacral anatomy.

Fifty randomly selected computed tomographic (CT) scans of the lumbosacral spine (25 males and 25 females) were studied to determine: 1) if the lateral sacral masses could safely accept a 7 mm diameter rod (i.e., intrasacral rod insertion) and 2) what percentage of patients, both males and females, demonstrated coverage of the posterolateral sacrum by the ilia (i.e., iliac buttressing). In all patients the lateral masses (i.e., the lateral intrasacral mass measurements) appeared wide enough on CT to allow for safe insertion of a 7 mm diameter rod, or other similar size implant, down to at least the level of S2. The smallest distance measured for the width between the posteromedial margin of the sacroiliac joint and the lateral cortex of the S1 neuroforamen (i.e., the lateral intrasacral mass measurement) at its location approximately midway (anteroposterior) through the sacrum on CT cuts was 17 mm (mean 28 mm). This would appear to give adequate room for a 7 mm diameter rod to be inserted at this level in the lateral sacrum (i.e., intrasacral rod insertion). Forty-six patients (24 males, 96%; and 22 females, 88%) appeared to have sufficient CT coverage of the sacrum to conceptually provide for so called "sacroiliac buttressing" of rods, if rods or other implants were to be inserted distally into the lateral masses. After a review of the sacral anatomy by CT it appears that: 1) insertion of rods into the lateral sacral masses (i.e. intrasacral rod insertions), or intrasacral fixation with other similar size implants, would be possible and apparently safe; and 2) the ilia along with the sacroiliac interosseous ligaments sufficiently surround the back and sides of the posterolateral sacrum in most patients (92%), at least by CT assessment, to conceptually offer an indirect "buttress" for implants so inserted. Theoretically, this could biomechanically help resist the flexural loads across the lumbosacral level and possibly provide a method for improved sacral fixation with spinal instrumentation in certain patients.

The facet syndrome. Myth or reality?

The lumbar facet joint has long been considered a significant source of low back pain (LBP). Facet blocks with anesthetic and cortisone, and even facet denervation procedures, have been recommended as treatment for patients with LBP. The literature, however, fails to conclusively document the role of the facet in the production of LBP. Based on a review of the literature and the author's clinical studies, the following statements appear to be appropriate and defensible: (1) The lumbar facet joints are very important biomechanically. (2) The facet is not a common or clear source of significant pain. (3) The facet syndrome is not a reliable clinical diagnosis. (4) Injection of intraarticular saline into the facets in control cases is as effective as local anesthetic and steroids in relieving the patient's pain temporarily. (5) Response to facet joint injection in patients with LBP does not correlate with or predict their clinical results after solid posterior lumbar fusion, and it should not be used preoperatively as a clinical criterion in selection of patients for fusion. (6) More prospective, controlled and randomized clinical studies are recommended.

Giant lateral neck swellings.

Four patients with extremely large lateral neck swellings are described. In the discussion the controversy about using radiotherapy: (i) to make an 'inoperable tumour operable', and (ii) to 'sterilise the operative field' is considered. It is concluded that modern radiotherapeutic techniques probably satisfy these requirements.

Coronal and sagittal plane spinal deformities correlating with back pain and pulmonary function in adult idiopathic scoliosis.

One hundred one referred adult patients (ages 20-63; mean, 36 years) with painful idiopathic scoliosis were evaluated. None had prior surgical treatment. Severity of pain was graded and localized over radiographic deformities in the coronal and sagittal planes. Radiographic changes in primary as well as full and fractional compensatory curves were studied. Degrees of scoliosis, percent correction on side bending, vertebral body rotation at curve apex, spinal balance, and lateral olisthesis in the coronal plane, degenerative disc disease, and other degenerative changes in all curves were measured and graded in both the coronal and sagittal planes. Lordosis and kyphosis were measured on all standing sagittal radiographs. Forty-one patients had pulmonary function studies. Multiple variable statistical analysis (Spearman correlation coefficients) of the data found fractional lumbosacral curves most painful and disabling. Scoliosis greater than 40 degrees and kyphosis greater than 50 degrees correlated with increasing pain and decreasing forced vital capacity. Reduction in forced vital capacity also correlated with curve rigidity. Rotation correlated closely with degrees of scoliosis (r = 0.70; P less than 0.0001) and had the highest correlation with pain (r = 0.59; P less than 0.0001) of all radiographic findings and deformities studied.

The neuroradiographic diagnosis of lumbar herniated nucleus pulposus: I. A comparison of computed tomography (CT), myelography, CT-myelography, discography, and CT-discography.

The accuracy of five imaging modalities for the diagnosis of lumbar herniated nucleus pulposus (HNP) is compared prospectively in 124 patients, all of whom underwent surgical exploration. All tests were read independently of each other and the level of confidence in each diagnosis was recorded. The results are based on negative (106) as well as positive (125) findings at the 231 disc sites (level and side) explored. Computed tomography-discography (disco-CT) was the most accurate test (87%) compared to 77% for CT-myelography (myelo-CT), 74% for CT, 70% for myelography, 64% for disc injection pain, and 58% for discography. The false positive rate was lower for disco-CT (19%) than for myelo-CT (24%), CT (24%), and myelography (30%). The false negative rate was also lower for disco-CT (8%) than for myelo-CT (22%), CT (29%), and myelography (30%). Disco-CT was the most accurate test (94%) in patients who had prior disc surgery compared with 81% for myelo-CT, 80% for CT, and 74% for myelography. Disco-CT was also the most accurate test for patients with foraminal HNP (91% compared with 71% for CT, 65% for myelo-CT, and 58% for myelography). Disc injection reproduced the patient's clinical pain pattern in only 36% of herniated discs. This test has high specificity (89%), but low sensitivity (43%). The risks from myelography followed by discography within a 72-hour period are similar to those reported for myelography alone. Disco-CT is the most accurate of these tests (P less than 0.05) for the diagnosis of lumbar HNP.(ABSTRACT TRUNCATED AT 250 WORDS)

The neuroradiographic diagnosis of lumbar herniated nucleus pulposus: II. A comparison of computed tomography (CT), myelography, CT-myelography, and magnetic resonance imaging.

The accuracy of computed tomography (CT), myelography, CT-myelography (myelo-CT) and magnetic resonance imaging (MRI) for the diagnosis of lumbar herniated nucleus pulposus (HNP) is compared prospectively in 59 patients, all of whom underwent surgical exploration. All tests were read independently of each other and the level of confidence in each diagnosis was recorded. The results are based on the negative (61) as well as positive (59) findings at the 120 disc sites (level and side) explored. Magnetic resonance imaging was the most accurate test (76.5%) compared with myelo-CT (76.0%), CT (73.6%), and myelography (71.4%). The false positive rate was lowest for MRI (13.5%) followed by myelography (13.7%), CT (13.8%), and myelo-CT (21.1%). The false negative rate was lowest for myelo-CT (27.2%) followed by MRI (35.7%), CT (40.2%), and myelography (44.1%). In that subset of 19 patients who had prior surgery, myelography was the most accurate means of diagnosing lumbar HNP (88.8%), followed by MRI (83.3%), myelo-CT (78.4%), and CT (72.6%). The false positive rates in these patients were 11.6% for myelography, 13.2% for MRI, 14.5% for CT, and 16.4% for myelo-CT; the false negative rates were 22.7% for MRI, 24.4% for myelography, 29.5% for myelo-CT, and 47.7% for CT. Magnetic resonance imaging compares very favorably with other currently available imaging modalities for diagnosing lumbar HNP. Magnetic resonance imaging is painless, has no known side effects or morbidity, no radiation exposure, and is noninvasive. The authors recommend it as the procedure of choice for the diagnosis of most lumbar disc herniations.

Enhancement of lumbar spine fusion by use of translaminar facet joint screws.

From January 1983 to March 1986 the authors have performed 88 consecutive lumbosacral spine fusion, enhanced with translaminar facet screws, as described by F. Magerl of St. Gallen, Switzerland. Forty-three patients have a follow-up of 12 months or greater, for a mean follow-up time of 16 months. The median time to fusion in this group was 6 months, with a range of 6 weeks to 10 months. Ninety-three percent of the patients were found to be clinically improved, and 91% of patients were judged solidly fused on evaluation of motion radiographs. Compared with our previously reported results for lumbar fusion without internal fixation, supplementation of lumbar fusion by translaminar facet screw fixation significantly improved the clinical results, as well as the time required for fusion, with no significant increased risk.

1988 Volvo award in clinical sciences. Facet joint injection in low-back pain. A prospective statistical study.

From January 1980 through December 1984, 454 patients were evaluated with facet joint injections. All had the chief complaint of low-back pain, normal neurologic examinations and no root tension signs. Three hundred and ninety completed the protocol, which included a lumbar motion pain assessment before and after facet injection. A total of 127 variables were studied. There were 229 males and 161 females with a median age of 38. Facet joint arthrograms were performed prior to intra-articular injection of local anesthetic and cortisone. Initial mean pain relief was only 29%. Variables correlating significantly (P less than 0.05) with more postinjection pain relief were older age, prior history of low-back pain, normal gait, maximum pain on extension following forward flexion in the standing position, and the absence of leg pain, muscle spasm and aggravation of pain on Valsalva. Greatest pain relief immediately after injection was seen with lumbar extension and rotation, motions reported to stress the facet joints or aggravate pain of facet joint origin. Patients with more pain on lumbar extension and rotation as a group, however, did not get more pain relief. From this study we were not able to identify clinical facet joint syndromes or predict patients responding better to this procedure. The facet joints were not commonly the single or primary source for low-back pain in the great majority (greater than 90%) of patients studied.

Foraminal and extraforaminal lumbar disc herniation: diagnosis and treatment.

During a 1-year period from December 1, 1984, through November 30, 1985, a total of 174 patients underwent lumbar discectomy for herniated nucleus pulposus. Eighteen (10.3%) were diagnosed as having foraminal or extraforaminal disc herniations. Sixteen patients are included in this study. All patients were evaluated with computed tomography, metrizamide myelography, discography, and discography-enhanced computed tomography (disco-CT). Accurate diagnosis of foraminal or extraforaminal herniation was made with disco-CT in 15 of 16 cases (93.8%), compared with discography alone (37.5%), computed tomography alone, and/or myelography-enhanced computed tomography (50%) and myelography alone (12.5%). Surgical treatment with bilateral hemilaminectomy, partial medial facetectomy, and partial internal foraminotomy, if needed, followed by discectomy is very effective and the favored surgical management for nerve root decompression in most all cases.

Incidence and severity of back pain in adult idiopathic scoliosis.

Incidence of back pain in a referred and followed group of 197 adults with idiopathic scoliosis and in a comparable control group of 180 adults without known spinal deformity was the same. Severity of pain, however, was greater in scoliotic patients. The clinical course of back pain in adults without spinal deformity and in scoliotics was different: 64% improvement in adults without scoliosis versus 83% persistence and progression in adults with scoliosis. Fifty-one percent of adult scoliotics (101 patients) had significant pain. Pain increased with age and degree of scoliotic curvature (P less than 0.0005). Patients with major lumbar curves had more pain. Major complaint was frequently below major deformity. Compensatory lumbosacral fractional curves were most painful and disabling. Pain comes mainly from concavity of curves and includes discogenic, facet joint, and radicular origins. Surgery significantly reduced pain (P less than 0.0001); conservative therapy did not. Eighty-three percent of surgical patients had sufficient pain relief to make surgery worthwhile at five years average follow-up.

Dynamic bone scanning in fractures.

In 20 cases routine static bone scans were no value in the detection of delayed fracture healing. Using the 7.5-15 min net uptake of technetium labelled phosphate, disturbed fracture healing was detected in a series, of 37 cases. Normally healing fractures had an increase of 3 per cent per month and delayed unions less than half that amount. Non-unions had no net uptake.