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Scintigraphic evaluation of tibial shaft fracture healing
Injury, Int. J. Care Injured 31 (2000) 51±54
www.elsevier.com/locate/injury
Scintigraphic evaluation of tibial shaft fracture healing J.W. Barros a, C.H. Barbieri b,*, C.D. Fernandes a a Department of Orthopaedics, FMTM, Uberaba MG, Brazil Department of Orthopaedic and Trauma Surgery, FMRP-USP, RibeiraÄo Preto SP, Brazil
b
Accepted 13 August 1999
Abstract A scintigraphic study of the healing process of type A and B closed tibial shaft fractures was carried out in 40 cases treated non-operatively, comprising 32 men and eight women aged 30.6 yr on average. Scintigraphic scans were obtained with technetium methylenediphosphonate (MDP-Tc99m, 25 mCi) at 6, 12 and 24 weeks after the fracture and an activity index was calculated taking the mean of three consecutive uptake counts for both fractured and normal opposite leg, used for comparison. The results showed that the activity index in general decreased progressively from the ®rst to the third evaluation, with little dierence in behaviour between the two types of fractures. However, for B type fractures the activity index remained stable from the ®rst to the second evaluation, followed by a marked decrease at the third evaluation, with a comparable end result for both fracture types. It was concluded that a decrease of the activity index occurs in both types of closed fractures undergoing uneventful healing and that such a decrease can be taken as a parameter for further studies which include delayed union and non-union. # 2000 Elsevier Science Ltd. All rights reserved.
1. Introduction Fractures of the tibial shaft are common and may be complicated by delayed union or nonunion, whose late diagnosis is usually easy thanks to the typical clinical ®ndings and X-ray appearance [8], particularly after it is well established, at 6 months from the fracture [9]. On the other hand, ongoing slow or poor healing is dicult to diagnose so that early treatment can be instituted. The use of bone scintigraphy has long been proposed to evaluate the bone healing process and its disturbances, beginning with the pioneer work by Bauer and Wenderberg [1], who used 47-calcium (Ca 47) and 85-strontium (Sr 85) as bone markers and concluded that high levels of isotope uptake would indicate nonunion. Later, it was found that normal bone healing is characterised by temporarily increased uptake, while delayed union is indicated by a more diuse uptake and nonunion by a persistently increased uptake [3]. * Corresponding author.
Despite the demonstration that a decreased isotope uptake indicates atrophic nonunion [6], increased uptake seems to be the common scintigraphic ®nding of most nonunions. Three dierent bone scan patterns have been demonstrated in the diagnosis of nonunions, the most frequent one (69.5%) being the intense, uniform and diuse uptake [2]. Early phase static and sequential scintigraphy have been used to try and detect `cold spots', supposed to indicate impaired blood supply and to correlate uptake pattern with fracture healing pattern, respectively. However, no correlation was demonstrated between the `cold spots' and uptake pattern or the progression of union [4]. The comparison between the fracture site and a normal area of the same bone, instead of the normal opposite tibia, was proposed by Smith et al. [10]. This would diminish the error factor due to the amount of circulating isotope in a bone aected by an overall increased blood ¯ow. Also, a 1.3 or lower quotient between those two areas would be a prognostic sign of nonunion, with 70% sensitivity and 90% speci®city. A similar ®nding was observed by Oni et al. [7], who
0020-1383/00/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 0 2 0 - 1 3 8 3 ( 9 9 ) 0 0 2 3 4 - X
52
J.W. Barros et al. / Injury, Int. J. Care Injured 31 (2000) 51±54
they were inversely proportional to the stability of ®xation [11]. It seemed to us that the value of scintigraphic evaluation of tibial shaft fracture healing and its anomalies is not suciently clear and that a pattern has not been de®ned for each event. We have, therefore, carried out the present study to try and de®ne scintigraphic parameters for tibial shaft fractures which healed within what is considered a normal time.
Fig. 1. Graphic of the distribution of the fractures according to type.
used static and dynamic scintigraphy to compare the fracture site and a normal area of the same bone. According to their ®ndings, an uptake ratio between the fracture site and the normal area greater than 2 at six weeks would indicate the potential to heal normally. Furthermore, a single static scintigram at this same time would be of predictive value. It is well known that the type of treatment may in¯uence the fracture outcome and this may also imply dierent results in the scintigraphic evaluation of tibial fractures. Accordingly, lower ratios were observed in quantitative early phase scintigraphy for fractures treated with a reamed nail (1.1 20.2) than for those treated with external ®xators (1.262 0.22) or plaster casts (1.4 2 0.21). The dierences between the uptake ratios were apparently related to biomechanical factors since
2. Material and methods Forty closed unilateral fractures of the tibial shaft of 32 men and eight women were studied. The patients' average age was 30.6 years (range: 19±57 years) and the right tibia was involved in 23 patients. The fractures were classi®ed according to the AO classi®cation [5], 31 being type A and nine being type B fractures (Fig. 1). All cases were treated non-operatively, by immediate closed reduction and immobilisation with a long leg plaster cast, the knee being kept in about 108 ¯exion. Surveillance of the circulatory condition of the leg was maintained for 48 h before patient discharge and patients with any circulatory disturbances were not considered for the study. Partial weight bearing was stimulated from the second week onward. The long leg plaster cast was replaced with a below-knee Sarmiento type plaster cast at 6 weeks after the fracture, full
Fig. 2. Scintigram of both fractured and normal tibia, showing the increased overall uptake in the fractured tibia, with more intense activity at the fracture site.
J.W. Barros et al. / Injury, Int. J. Care Injured 31 (2000) 51±54
weight bearing being allowed thereafter. X-ray controls were taken at 2, 6 and 12 weeks after the fracture and at 4-week intervals thereafter, till union was solid. Scintigraphic evaluation of all cases was carried out at 6, 12 and 24 weeks after the fracture using a gamma camera provided with a high resolution collimator. The plaster cast was removed and the patient received an intravenous injection of 25 mCi of technetium methylene-diphosphonate (99mTc-MDP) three hours before the examination. The patient was positioned supine on the table, both legs parallel and in neutral rotation. Three consecutive counts were taken from each leg, the average of which was calculated. The quotient between the average count on the fractured and normal tibia was the individual activity index (AI) for each period. A general AI as well as a separate one for type A and B fractures was calculated for each period. An increase or decrease of 20% or more was referred to as marked increase or decrease, respectively, while variations of less than 20% were referred to as stable or stability. The data were submitted to analysis of variance (ANOVA), with signi®cance at the 5% level ( p < 0.05). 3. Results Bone healing occurred in all cases within up to 20 weeks (average: 12 weeks), as detected by clinical and radiographic examination. The scintiscans showed the usual appearance of increased radionuclide uptake at the fracture site (Fig. 2). The overall results showed that, between the ®rst and second evaluations, the individual AI remained stable in 21 cases, decreased markedly in 14 and increased markedly in the remaining ®ve. Between the second and third evaluation, a marked decrease of the individual AI was observed in 29 cases, while stability occurred in seven and a marked increase in four. Considering the ®rst and third evaluations, a marked decrease of the individual AI was observed in the vast majority of cases (31), getting to 71% in one case. Stability was observed in seven cases and increase in two. The general average AI was 3.33 (variation: 1.19± 4.76) at 6 weeks, 2.97 (variation: 1.56±6.2) at 12 weeks and 2.28 (variation: 1.19±4.7) at 24 weeks, corresponding to an 11% decrease between the ®rst and second evaluation and a 23% decrease between the second and third. Between the ®rst and third evaluation, the decrease was 31.5%. Separate analysis according to fracture type showed that the average AI was 3.26 (variation: 1.19±4.76), 2.64 (variation: 1.56±4.1) and 2.25 (variation: 1.19±4.7) for type A fractures and 3.57 (variation: 1.8±6), 3.69 (variation: 1.73±6.2) and 2.38 (variation: 1.2±3.9) for type B fractures, at 6, 12 and 24 weeks, respectively.
53
Fig. 3. Evolution of the general activity index and activity indices according to fracture type.
From the ®rst to the second evaluation, the AI of type A fractures remained stable in 16 cases, but presented a marked decrease in 12 and a marked increase in only three, altogether corresponding to a 19% decrease. For type B fractures, the AI remained stable in ®ve, but presented a marked decrease in two and a marked increase in two, altogether corresponding to a 3.3% increase (Fig. 3). From the second to the third evaluation, the AI of type A fractures remained stable in 22 cases, while a marked decrease was observed in six and a marked increase in three, corresponding to a 15% decrease. For type B fractures, the AI showed stability in only one, a marked increase in another one, but a marked decrease in seven, corresponding to a 35% overall decrease. When the ®rst and third evaluations are considered alone, type A fractures showed a marked decrease in 24 cases, stability in six and a marked increase in only one, corresponding to an overall 31% decrease. Type B fractures showed a marked decrease in seven cases, a marked increase in one and stability in another, with an overall 33% decrease. ANOVA showed that the data were signi®cant for the progressive overall decrease of uptake with time p 0:0001). 4. Discussion Bone scintigraphy has a potential for application to predict the future evolution of bone healing, whether to complete healing or to a healing anomaly, such as delayed union or nonunion. However, the scintigraphic parameters of normal bone healing are not clearly de®ned, although it has been suggested that radionuclide uptake decreases with time [1,3,4]. In this study, a scintigraphic evaluation of the normal bone healing process was carried out from the beginning of ossi®cation to the moment of well de®ned ossi®cation, as detected by conventional X-ray studies
54
J.W. Barros et al. / Injury, Int. J. Care Injured 31 (2000) 51±54
at 24 weeks after the fracture. An activity index (AI), de®ned as the isotope uptake ratio between the fractured and the normal tibia, was used for comparisons, as usual. The comparison between the fracture site and a normal area of the same bone has been recently proposed, based on the fact that the increased blood ¯ow in the fractured bone leads to an increased amount of locally circulating radionuclide. As a result of this, the overall scintigraphic count in the fractured bone is in fact the sum of the actual radionuclide bone uptake and the circulating radionuclide [7,10,11]. We have preferred to establish comparisons with the opposite normal tibia, considering that the increased blood ¯ow in the fractured tibia is part of the bone healing process and should not be exclude from the calculations, unless we were only interested in the actual bone metabolic activity. Furthermore, all counts were taken in a late phase (three hours from the radionuclide injection), when most of the radionuclide has already been taken up by the metabolically active bone and the amount of circulating radionuclide is very small. The general average AI remained practically stable from the ®rst to the second evaluation (3.33 to 2.97, or 11%), indicating that the metabolic activity at the fracture site was in a plateau, compatible with the radiographic appearance at both times. However, there was a marked decrease from the second to the third evaluation (2.97 to 2.28, or 23%), when the fracture was already undergoing remodelling, also evident by X-ray examination. The decrease of the general average AI from the ®rst to the third evaluations was even more marked (31.5%). This probably indicates that from the moment when ossi®cation begins to when remodelling is taking place there is a marked decay in the metabolic activity of the bone healing process, which becomes slower. The correlation of the general average AI with the fracture type showed that type B fractures tended to present higher AI than type A fractures, particularly in the ®rst and second evaluations. The AI for both types became similar at the time of the third evaluation. Such ®nding is compatible with the fact that type B fractures are produced by a higher energy trauma, involving wider bone and soft tissue injury and need a higher metabolic activity to heal. Our data indicate that the AI of fractures undergoing a normal healing process follows a pattern of
progressive decrease from the beginning of ossi®cation to remodelling. We conclude that the pattern demonstrated here is reliable and should be used as a parameter for further studies. It is of predicting value since the change in the pattern, such as the persistence of increased AI, will probably indicate the future development of a healing anomaly as delayed union or nonunion.
References [1] Bauer GCH, Wenderberg B. External counting of Ca47 and Sr85 in studies of skeletal lesions in man. Journal of Bone and Joint Surgery 1959;41:558±80. [2] Esterhai JL, Brighton CT, Heppenstall RB, et al. Detection of synovial pseudarthrosis by 99mTc scintigraphy: application to treatment of traumatic nonunion with constant direct current. Clinical Orthopedics and Related Research 1981;161:15±23. [3] Fueger GF, Tscherne H, Schwartz G, Szyskowitz R. Szintigraphische Untersuchungen mit 87m Strontium zitrat zur Beurteilungen der Frakturheilung. In: Glauner R, editor. Angiologie und Szintigraphie bei Knochen und Gelenkeskrankungen. Stuttgart: Georg Thieme Verlag, 1971. p. 133±43. [4] Gregg PJ, Clayton CB, Fenwick JD, et al. Static and sequential dynamic scintigraphy of the tibia follwing fracture. Injury 1986;17:95±103. [5] MuÈller ME, Nazarian S, Koch P. Classi®cation AO des fractures. Berlin Heidelberg: Springer-Verlag, 1987. [6] Muhein G. Assessment of fracture healing in man by serial 87m strontium scintimetry. Acta Orthopaedica Scandinavica 1973;44:621±7. [7] Oni OA, Graebe A, Pearse M, Gregg PJ. Prediction of the healing potential of closed adult tibial shaft fractures by bone scintigraphy. Clinical Orthopedics and Related Research 1989;245:239±45. [8] Rodgers LF. Traumatic Lesions of Bone and Joints. In: Juhl JH, Crummy AB, Kuhlman JE, editors. Paul and Juhl's Essentials of Radiologic Imaging, 7th ed. Lippincott-Raven, Philadelphia, 1998, pp. 29, 40-41. [9] Russell TA, Taylor JC, LaVelle DG. Fractures of the tibia and ®bula. In: Rockwood Jr. CA, Green DP, Bucholz RW, editors. Rockwood and Green's fractures in adults, 3rd ed. Philadelphia: J.B. Lippincott Co, 1991. p. 1952. [10] Smith MA, Jones EA, Strachan RK, Nicoll JJ, Best JJK, Tothill P, Hughes SPF. Prediction of fracture healing in the tibia by quantitative radionuclide imaging. Journal of Bone and Joint Surgery 1987;69:441±7. [11] Wallace L, Strachan RK, Blane A, Best JJK, Hughes SPF. Quantitative early phase scintigraphy in the prediction of healing of tibial fractures. Skeletal Radiology 1992;21:241±5.
www.elsevier.com/locate/injury
Scintigraphic evaluation of tibial shaft fracture healing J.W. Barros a, C.H. Barbieri b,*, C.D. Fernandes a a Department of Orthopaedics, FMTM, Uberaba MG, Brazil Department of Orthopaedic and Trauma Surgery, FMRP-USP, RibeiraÄo Preto SP, Brazil
b
Accepted 13 August 1999
Abstract A scintigraphic study of the healing process of type A and B closed tibial shaft fractures was carried out in 40 cases treated non-operatively, comprising 32 men and eight women aged 30.6 yr on average. Scintigraphic scans were obtained with technetium methylenediphosphonate (MDP-Tc99m, 25 mCi) at 6, 12 and 24 weeks after the fracture and an activity index was calculated taking the mean of three consecutive uptake counts for both fractured and normal opposite leg, used for comparison. The results showed that the activity index in general decreased progressively from the ®rst to the third evaluation, with little dierence in behaviour between the two types of fractures. However, for B type fractures the activity index remained stable from the ®rst to the second evaluation, followed by a marked decrease at the third evaluation, with a comparable end result for both fracture types. It was concluded that a decrease of the activity index occurs in both types of closed fractures undergoing uneventful healing and that such a decrease can be taken as a parameter for further studies which include delayed union and non-union. # 2000 Elsevier Science Ltd. All rights reserved.
1. Introduction Fractures of the tibial shaft are common and may be complicated by delayed union or nonunion, whose late diagnosis is usually easy thanks to the typical clinical ®ndings and X-ray appearance [8], particularly after it is well established, at 6 months from the fracture [9]. On the other hand, ongoing slow or poor healing is dicult to diagnose so that early treatment can be instituted. The use of bone scintigraphy has long been proposed to evaluate the bone healing process and its disturbances, beginning with the pioneer work by Bauer and Wenderberg [1], who used 47-calcium (Ca 47) and 85-strontium (Sr 85) as bone markers and concluded that high levels of isotope uptake would indicate nonunion. Later, it was found that normal bone healing is characterised by temporarily increased uptake, while delayed union is indicated by a more diuse uptake and nonunion by a persistently increased uptake [3]. * Corresponding author.
Despite the demonstration that a decreased isotope uptake indicates atrophic nonunion [6], increased uptake seems to be the common scintigraphic ®nding of most nonunions. Three dierent bone scan patterns have been demonstrated in the diagnosis of nonunions, the most frequent one (69.5%) being the intense, uniform and diuse uptake [2]. Early phase static and sequential scintigraphy have been used to try and detect `cold spots', supposed to indicate impaired blood supply and to correlate uptake pattern with fracture healing pattern, respectively. However, no correlation was demonstrated between the `cold spots' and uptake pattern or the progression of union [4]. The comparison between the fracture site and a normal area of the same bone, instead of the normal opposite tibia, was proposed by Smith et al. [10]. This would diminish the error factor due to the amount of circulating isotope in a bone aected by an overall increased blood ¯ow. Also, a 1.3 or lower quotient between those two areas would be a prognostic sign of nonunion, with 70% sensitivity and 90% speci®city. A similar ®nding was observed by Oni et al. [7], who
0020-1383/00/$ - see front matter # 2000 Elsevier Science Ltd. All rights reserved. PII: S 0 0 2 0 - 1 3 8 3 ( 9 9 ) 0 0 2 3 4 - X
52
J.W. Barros et al. / Injury, Int. J. Care Injured 31 (2000) 51±54
they were inversely proportional to the stability of ®xation [11]. It seemed to us that the value of scintigraphic evaluation of tibial shaft fracture healing and its anomalies is not suciently clear and that a pattern has not been de®ned for each event. We have, therefore, carried out the present study to try and de®ne scintigraphic parameters for tibial shaft fractures which healed within what is considered a normal time.
Fig. 1. Graphic of the distribution of the fractures according to type.
used static and dynamic scintigraphy to compare the fracture site and a normal area of the same bone. According to their ®ndings, an uptake ratio between the fracture site and the normal area greater than 2 at six weeks would indicate the potential to heal normally. Furthermore, a single static scintigram at this same time would be of predictive value. It is well known that the type of treatment may in¯uence the fracture outcome and this may also imply dierent results in the scintigraphic evaluation of tibial fractures. Accordingly, lower ratios were observed in quantitative early phase scintigraphy for fractures treated with a reamed nail (1.1 20.2) than for those treated with external ®xators (1.262 0.22) or plaster casts (1.4 2 0.21). The dierences between the uptake ratios were apparently related to biomechanical factors since
2. Material and methods Forty closed unilateral fractures of the tibial shaft of 32 men and eight women were studied. The patients' average age was 30.6 years (range: 19±57 years) and the right tibia was involved in 23 patients. The fractures were classi®ed according to the AO classi®cation [5], 31 being type A and nine being type B fractures (Fig. 1). All cases were treated non-operatively, by immediate closed reduction and immobilisation with a long leg plaster cast, the knee being kept in about 108 ¯exion. Surveillance of the circulatory condition of the leg was maintained for 48 h before patient discharge and patients with any circulatory disturbances were not considered for the study. Partial weight bearing was stimulated from the second week onward. The long leg plaster cast was replaced with a below-knee Sarmiento type plaster cast at 6 weeks after the fracture, full
Fig. 2. Scintigram of both fractured and normal tibia, showing the increased overall uptake in the fractured tibia, with more intense activity at the fracture site.
J.W. Barros et al. / Injury, Int. J. Care Injured 31 (2000) 51±54
weight bearing being allowed thereafter. X-ray controls were taken at 2, 6 and 12 weeks after the fracture and at 4-week intervals thereafter, till union was solid. Scintigraphic evaluation of all cases was carried out at 6, 12 and 24 weeks after the fracture using a gamma camera provided with a high resolution collimator. The plaster cast was removed and the patient received an intravenous injection of 25 mCi of technetium methylene-diphosphonate (99mTc-MDP) three hours before the examination. The patient was positioned supine on the table, both legs parallel and in neutral rotation. Three consecutive counts were taken from each leg, the average of which was calculated. The quotient between the average count on the fractured and normal tibia was the individual activity index (AI) for each period. A general AI as well as a separate one for type A and B fractures was calculated for each period. An increase or decrease of 20% or more was referred to as marked increase or decrease, respectively, while variations of less than 20% were referred to as stable or stability. The data were submitted to analysis of variance (ANOVA), with signi®cance at the 5% level ( p < 0.05). 3. Results Bone healing occurred in all cases within up to 20 weeks (average: 12 weeks), as detected by clinical and radiographic examination. The scintiscans showed the usual appearance of increased radionuclide uptake at the fracture site (Fig. 2). The overall results showed that, between the ®rst and second evaluations, the individual AI remained stable in 21 cases, decreased markedly in 14 and increased markedly in the remaining ®ve. Between the second and third evaluation, a marked decrease of the individual AI was observed in 29 cases, while stability occurred in seven and a marked increase in four. Considering the ®rst and third evaluations, a marked decrease of the individual AI was observed in the vast majority of cases (31), getting to 71% in one case. Stability was observed in seven cases and increase in two. The general average AI was 3.33 (variation: 1.19± 4.76) at 6 weeks, 2.97 (variation: 1.56±6.2) at 12 weeks and 2.28 (variation: 1.19±4.7) at 24 weeks, corresponding to an 11% decrease between the ®rst and second evaluation and a 23% decrease between the second and third. Between the ®rst and third evaluation, the decrease was 31.5%. Separate analysis according to fracture type showed that the average AI was 3.26 (variation: 1.19±4.76), 2.64 (variation: 1.56±4.1) and 2.25 (variation: 1.19±4.7) for type A fractures and 3.57 (variation: 1.8±6), 3.69 (variation: 1.73±6.2) and 2.38 (variation: 1.2±3.9) for type B fractures, at 6, 12 and 24 weeks, respectively.
53
Fig. 3. Evolution of the general activity index and activity indices according to fracture type.
From the ®rst to the second evaluation, the AI of type A fractures remained stable in 16 cases, but presented a marked decrease in 12 and a marked increase in only three, altogether corresponding to a 19% decrease. For type B fractures, the AI remained stable in ®ve, but presented a marked decrease in two and a marked increase in two, altogether corresponding to a 3.3% increase (Fig. 3). From the second to the third evaluation, the AI of type A fractures remained stable in 22 cases, while a marked decrease was observed in six and a marked increase in three, corresponding to a 15% decrease. For type B fractures, the AI showed stability in only one, a marked increase in another one, but a marked decrease in seven, corresponding to a 35% overall decrease. When the ®rst and third evaluations are considered alone, type A fractures showed a marked decrease in 24 cases, stability in six and a marked increase in only one, corresponding to an overall 31% decrease. Type B fractures showed a marked decrease in seven cases, a marked increase in one and stability in another, with an overall 33% decrease. ANOVA showed that the data were signi®cant for the progressive overall decrease of uptake with time p 0:0001). 4. Discussion Bone scintigraphy has a potential for application to predict the future evolution of bone healing, whether to complete healing or to a healing anomaly, such as delayed union or nonunion. However, the scintigraphic parameters of normal bone healing are not clearly de®ned, although it has been suggested that radionuclide uptake decreases with time [1,3,4]. In this study, a scintigraphic evaluation of the normal bone healing process was carried out from the beginning of ossi®cation to the moment of well de®ned ossi®cation, as detected by conventional X-ray studies
54
J.W. Barros et al. / Injury, Int. J. Care Injured 31 (2000) 51±54
at 24 weeks after the fracture. An activity index (AI), de®ned as the isotope uptake ratio between the fractured and the normal tibia, was used for comparisons, as usual. The comparison between the fracture site and a normal area of the same bone has been recently proposed, based on the fact that the increased blood ¯ow in the fractured bone leads to an increased amount of locally circulating radionuclide. As a result of this, the overall scintigraphic count in the fractured bone is in fact the sum of the actual radionuclide bone uptake and the circulating radionuclide [7,10,11]. We have preferred to establish comparisons with the opposite normal tibia, considering that the increased blood ¯ow in the fractured tibia is part of the bone healing process and should not be exclude from the calculations, unless we were only interested in the actual bone metabolic activity. Furthermore, all counts were taken in a late phase (three hours from the radionuclide injection), when most of the radionuclide has already been taken up by the metabolically active bone and the amount of circulating radionuclide is very small. The general average AI remained practically stable from the ®rst to the second evaluation (3.33 to 2.97, or 11%), indicating that the metabolic activity at the fracture site was in a plateau, compatible with the radiographic appearance at both times. However, there was a marked decrease from the second to the third evaluation (2.97 to 2.28, or 23%), when the fracture was already undergoing remodelling, also evident by X-ray examination. The decrease of the general average AI from the ®rst to the third evaluations was even more marked (31.5%). This probably indicates that from the moment when ossi®cation begins to when remodelling is taking place there is a marked decay in the metabolic activity of the bone healing process, which becomes slower. The correlation of the general average AI with the fracture type showed that type B fractures tended to present higher AI than type A fractures, particularly in the ®rst and second evaluations. The AI for both types became similar at the time of the third evaluation. Such ®nding is compatible with the fact that type B fractures are produced by a higher energy trauma, involving wider bone and soft tissue injury and need a higher metabolic activity to heal. Our data indicate that the AI of fractures undergoing a normal healing process follows a pattern of
progressive decrease from the beginning of ossi®cation to remodelling. We conclude that the pattern demonstrated here is reliable and should be used as a parameter for further studies. It is of predicting value since the change in the pattern, such as the persistence of increased AI, will probably indicate the future development of a healing anomaly as delayed union or nonunion.
References [1] Bauer GCH, Wenderberg B. External counting of Ca47 and Sr85 in studies of skeletal lesions in man. Journal of Bone and Joint Surgery 1959;41:558±80. [2] Esterhai JL, Brighton CT, Heppenstall RB, et al. Detection of synovial pseudarthrosis by 99mTc scintigraphy: application to treatment of traumatic nonunion with constant direct current. Clinical Orthopedics and Related Research 1981;161:15±23. [3] Fueger GF, Tscherne H, Schwartz G, Szyskowitz R. Szintigraphische Untersuchungen mit 87m Strontium zitrat zur Beurteilungen der Frakturheilung. In: Glauner R, editor. Angiologie und Szintigraphie bei Knochen und Gelenkeskrankungen. Stuttgart: Georg Thieme Verlag, 1971. p. 133±43. [4] Gregg PJ, Clayton CB, Fenwick JD, et al. Static and sequential dynamic scintigraphy of the tibia follwing fracture. Injury 1986;17:95±103. [5] MuÈller ME, Nazarian S, Koch P. Classi®cation AO des fractures. Berlin Heidelberg: Springer-Verlag, 1987. [6] Muhein G. Assessment of fracture healing in man by serial 87m strontium scintimetry. Acta Orthopaedica Scandinavica 1973;44:621±7. [7] Oni OA, Graebe A, Pearse M, Gregg PJ. Prediction of the healing potential of closed adult tibial shaft fractures by bone scintigraphy. Clinical Orthopedics and Related Research 1989;245:239±45. [8] Rodgers LF. Traumatic Lesions of Bone and Joints. In: Juhl JH, Crummy AB, Kuhlman JE, editors. Paul and Juhl's Essentials of Radiologic Imaging, 7th ed. Lippincott-Raven, Philadelphia, 1998, pp. 29, 40-41. [9] Russell TA, Taylor JC, LaVelle DG. Fractures of the tibia and ®bula. In: Rockwood Jr. CA, Green DP, Bucholz RW, editors. Rockwood and Green's fractures in adults, 3rd ed. Philadelphia: J.B. Lippincott Co, 1991. p. 1952. [10] Smith MA, Jones EA, Strachan RK, Nicoll JJ, Best JJK, Tothill P, Hughes SPF. Prediction of fracture healing in the tibia by quantitative radionuclide imaging. Journal of Bone and Joint Surgery 1987;69:441±7. [11] Wallace L, Strachan RK, Blane A, Best JJK, Hughes SPF. Quantitative early phase scintigraphy in the prediction of healing of tibial fractures. Skeletal Radiology 1992;21:241±5.