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METACARPAL DESCENT, DEFINITION AND NORMAL RANGE
METACARPAL DESCENT, DEFINITION AND NORMAL RANGE S. C. TUCKER and O. G. TITLEY From the West Midlands Regional Unit for Plastic and Reconstructive Surgery, Wordsley Hospital, Stream Road, Stourbridge, West Midlands, UK
Metacarpal descent, an indication of carpometacarpal (CMC) joint mobility, was measured in 90 normal subjects by assessing the alignment of the metacarpal heads with the hand in a relaxed posture and when making a tight fist. Metacarpal descent was greater in women. Hand dominance was associated with an increase in positional angles but not metacarpal descent. Journal of Hand Surgery (British and European Volume, 2002) 27B: 3: 289–292 is relaxed but becomes deeper and wider as the fifth metacarpal descends during power grip (Zancolli, 1979). This allows cupping of the hand and moulding to objects for power grip, and grip strength is decreased if little finger carpometacarpal joint movement is restricted (Wise, 1975). The measurement of metacarpal descent may therefore be a useful indicator of hand function, particularly in cases of disease or trauma affecting the little finger carpometacarpal joint.
INTRODUCTION Metacarpal descent is a term that has been loosely used to describe the change in the profile of the metacarpal heads that occurs when the hand is moved from a relaxed posture to a clenched fist (Clendenin and Smith, 1984) (Fig 1). Despite the fact that hand movements are extremely complex, simple goniometer measurements are reliable as long as hand position and goniometer placement are standardized (Weiss et al., 1994). With this in mind we have measured metacarpal descent in 90 subjects using a simple, reproducible method. The distal row of carpal bones form a fixed transverse arch, by virtue of their anatomic configurations and ligamentous connections. The ring and little fingers on the ulnar side, and the thumb on the radial side, form two mobile longitudinal arches with varying ranges of motion at the carpometacarpal joints, but the second and third metacarpals are relatively firmly fixed to the distal carpal row (Gurland, 1992). This results in a complex, mobile transverse arch at the level of the metacarpal heads which is shallow when the hand
METHOD Measurements were obtained from 45 men and 45 women, who were stratified equally into the age ranges 20–40, 41–60 and over 60 years. Each subject’s age, hand dominance and occupation (manual or nonmanual) were recorded. Individuals with previous hand pathology were excluded from the study. Since the second and third carpometacarpal joints do not move significantly during the active formation of a fist, a line joining the skyline of the second and third
Fig 1 Metacarpal descent refers to the change in the profile of the metacarpal heads when the hand moves from a relaxed posture (a) to a clenched fist position (b). 289
290
Fig 2 The angle measured with the goniometer is represented here as angle x. It is the angle between a line joining the skyline view of the second and third metacarpals and another line joining the skyline view of the third and fifth metacarpals.
metacarpal heads was used as a reference, from which the descent of the fifth metacarpal head was measured. The position of the fifth metacarpal head was thus documented as an angle, as represented by angle ‘‘x’’ in Fig 2. We defined metacarpal descent as the difference between angle ‘‘x’’ in the relaxed and clenched fist positions. Metacarpal descent was also calculated for the fourth metacarpal by repeating these measurements in relation to the fourth metacarpal head. The relaxed position was standardized by placing the forearm, wrist and palm on a shaped block of wood such that the wrist was held in 251–301 extension by a triangular spur that supported the third metacarpal only (Fig 3). It was ensured that movement of the fourth and fifth metacarpals was not impaired and that the fingers hung freely over the end of the block. The clenched fist position was assessed by asking
Fig 3 The relaxed posture is standardized by placing the hand on a shaped block of wood such that the 3rd metacarpal is supported but the fingers hang freely over the end.
THE JOURNAL OF HAND SURGERY VOL. 27B No. 3 JUNE 2002
the subject to squeeze a softened piece of putty as hard as possible. During a pilot study it was found that subjects often had difficulty forming a natural fist when they knew which part of the hand was going to be measured, but giving them something to squeeze distracted them and allowed them to clench the hand normally. The putty ball was small and soft so that it was squeezed between the fingers when the patient formed a fist and thus did not prevent the joints from fully flexing. Measurements were obtained with a clear goniometer (BaselineTM) so that the profile of the metacarpal heads could be easily seen. One limb of the goniometer was aligned with the skyline view of the second and third metacarpals and the angle ‘‘x’’ was then determined by aligning the other limb of the goniometer with the skyline view of the fourth or fifth metacarpal (Fig 4). A reproducibility study was first carried out to ensure that this method of measuring metacarpal descent was accurate. One subject was measured three times by each of three assessors. The main study was carried out by a single assessor taking all the measurements. Results were analysed using Student’s t-test and analysis of variance. RESULTS Repeated measurements taken by the same observer in the manner described varied by +/ 11. Measurement of the positional angles showed inter-observer differences with a range of +/ 21. The results for the fourth metacarpal are shown in Tables 1 and 2 and those for the fifth metacarpal in Tables 3 and 4. Metacarpal descent of the fifth metacarpal of both hands was significantly greater for women, with a mean of 71 (95% CI, 61–81) as compared with a mean of 41 (95% CI 31–51) for the men (Students t-test, Po0.001). In the men the angle ‘‘x’’ for the fifth metacarpal decreased with age, but the difference between
Fig 4 Measurements are taken with a clear goniometer.
METACARPAL DESCENT
291
Table 1FMean (range) angles (angle ‘‘x’’) between the third and fourth metacarpal heads in men (n=45) Right
21–40 41–60 460 Total
Relaxed
Fist
31 27 25 28
32 30 24 29
(18–40) (17–40) (15–32) (15–40)
Left Metacarpal descent
(26–43) (15–45) (15–40) (15–45)
5 4 6 5
(1–9) (0–10) (0–13) (0–13)
Relaxed
Fist
30 26 25 27
31 28 24 28
(18–40) (18–37) (15–31) (15–40)
Metacarpal descent
(15–40) (20–35) (17–34) (15–40)
3 4 3 3
(0–9) (0–9) (0–6) (0–9)
Table 2FMean (and range) angles (angle ‘‘x’’) between the third and fourth metacarpal heads in women (n=45) Right
21–40 41–60 460 Total
Relaxed
Fist
31 32 31 31
31 29 30 30
(20–42) (21–47) (21–40) (20–47)
Left Metacarpal descent
(22–38) (20–39) (25–44) (20–44)
5 5 4 5
(0–13) (0–14) (0–11) (0–14)
Relaxed
Fist
27 30 30 29
26 30 29 28
(13–37) (25–40) (19–40) (13–40)
Metacarpal descent
(19–35) (22–40) (18–48) (18–48)
5 6 5 5
(0–17) (0–12) (1–11) (0–17)
Table 3FMean (and range) angles (angle ‘‘x’’ ) between the third and the fifth metacarpal heads in men (n=45) Right
21–40 41–60 460 Total
Relaxed
Fist
37 33 30 34
37 33 28 32
(28–46) (22–46) (20–42) (20–46)
Left Metacarpal descent
(27–43) (19–49) (17–42) (17–49)
4 4 6 5
(1–12) (0–9) (1–12) (0–12)
Relaxed
Fist
33 33 29 32
34 32 25 30
(20–42) (21–40) (15–39) (15–42)
Metacarpal descent
(19–40) (22–40) (17–36) (17–40)
4 3 6 4
(0–9) (0–10) (1–10) (0–10)
Table 4FResults of the mean (range) angles in degrees between the third and the fifth metacarpal heads in women (n=45) Right
21–40 41–60 460 Total
Relaxed
Fist
32 37 35 35
34 33 31 33
(23–40) (25–54) (21–44) (21–54)
(23–45) (19–42) (12–48) (12–48)
Left Metacarpal descent 6 8 8 7
(0–20) (1–19) (0–20) (0–20)
angle ‘‘x’’ in the relaxed and fist positions remained the same. Therefore metacarpal descent, as we have defined it, did not change. This decrease in angle ‘‘x’’ was significant for the right fifth metacarpal relaxed and fist positions (ANOVA: Po0.01 and 0.002 respectively) and the fist position on the left (ANOVA: Po0.0002). In contrast, women showed no significant differences between the various age groups for any of the variables tested. Angle ‘‘x’’ for the fifth metacarpal was greater in the dominant hand in the fist position. Mean angle ‘‘x’’ values were 331 (95% CI 311–341) in the dominant hand and 301 (95% CI 291–311) in the nondominant hand (t-test, Po0.005). There was no relationship between metacarpal descent and hand dominance. There were 23 manual workers and 67 non-manual workers. There were no significant differences in angle ‘‘x’’ or metacarpal descent between these two groups.
Relaxed
Fist
30 34 30 31
28 31 28 29
(13–40) (25–45) (10–47) (10–47)
(18–36) (24–42) (15–47) (15–47)
Metacarpal descent 6 7 5 6
(2–13) (1–17) (0–12) (0–17)
Angle ‘‘x’’ for the fifth metacarpal bore no relationship to angle ‘‘x’’ for the fourth metacarpal in either of the hand positions.
DISCUSSION Previous studies have shown up to 401 of flexion/ extension and slight supination at the articulation between the base of the fifth metacarpal and the hamate (Wise, 1975; Clendenin and Smith, 1984). However, we feel that measurement of metacarpal descent is more clinically relevant and reproducible than measurement of flexion/extension at the carpometacarpal joint, especially as this requires specialist instrumentation. The range of motion at any joint is limited by three factors: the shape of the bones themselves, the configuration of the ligaments, and the volume of the soft tissue that lies between the two bones involved. Angle
292
‘‘x’’ and metacarpal descent are therefore dependent on how the above factors affect the little finger carpometacarpal joint, and this probably explains the differences which we found in our population. For example, the difference between the men and women is probably due to differences in ligament laxity. Decreasing values for angle ‘‘x’’ with age, as found in the men, indicate flattening of the hand. This may have been due to arthritic changes affecting the shape of the joints, and may be greater in the men because of the heavier demands placed on their hand joints. Metacarpal descent of the fourth ray is independent of the fifth and thus the position of the fourth metacarpal head is probably dependent on factors related to the ring finger carpometacarpal joint rather than the mobility of the fifth metacarpal. The formation of the distal metacarpal arch is more variable than might be assumed. The measurement of metacarpal descent would be a useful tool in the assessment of disease, trauma or surgery to the little finger carpometacarpal joint, and also in determining the correct position for fusion on the rare occasions when arthrodesis of this joint is indicated. Since the movement of the little finger carpometacarpal joint is what allows the hand to mould itself around objects in power grip, fusion of this joint should not be undertaken unless the level of pain is severe. We would recommend that the position of the fusion should be within the functional arc of carpometacarpal joint
THE JOURNAL OF HAND SURGERY VOL. 27B No. 3 JUNE 2002
movement as this should cause less disability than not being able to place the palm absolutely flat (Gurland, 1992). Therefore in cases where fusion of the little finger carpometacarpal joint is indicated, a knowledge of the normal range for metacarpal descent may be helpful. Acknowledgements Michael Tonkin, Professor of Hand Surgery, Royal North Shore Hospital, Sydney. Medical Photography, Selly Oak. Medical Illustration, Frenchay Hospital. Pete Nightingale, Department of Medical Statistics, Selly Oak.
References Clendenin MB, Smith RJ (1984). Fifth metacarpal/hamate arthrodesis for posttraumatic osteoarthritis. Journal of Hand Surgery, 9A: 374–378. Gurland M (1992). Carpometacarpal joint injuries of the fingers. Hand Clinics, 8: 733–744. Weiss PI, August S, Peters G, Sampalis J (1994). Using the Exos Handmaster to measure digital range of motion: reliability and validity. Medical Engineering and Physics, 16: 323–328. Wise KS (1975). The anatomy of the metacarpophalangeal joints, with observations of the aetiology of ulnar drift. Journal of Bone and Joint Surgery, 57(B): 485–490. Zancolli E. Normal balance of the metacarpophalangeal joint during finger function. In: Structural and dynamic bases of hand surgery. Philadelphia, J.B. Lippincott Company, 1979: 326–336.
Received: 17 November 2000 Accepted after revision: 9 January 2002 Mrs S. C. Tucker, 1 Hillsborough, Main Road, Temple Cloud, Bristol BS39 5BL, UK. E-mail: [email protected] r 2002 The British Society for Surgery of the Hand doi: 10.1054/jhsb.2002.0751, available online at http://www.idealibrary.com on
Metacarpal descent, an indication of carpometacarpal (CMC) joint mobility, was measured in 90 normal subjects by assessing the alignment of the metacarpal heads with the hand in a relaxed posture and when making a tight fist. Metacarpal descent was greater in women. Hand dominance was associated with an increase in positional angles but not metacarpal descent. Journal of Hand Surgery (British and European Volume, 2002) 27B: 3: 289–292 is relaxed but becomes deeper and wider as the fifth metacarpal descends during power grip (Zancolli, 1979). This allows cupping of the hand and moulding to objects for power grip, and grip strength is decreased if little finger carpometacarpal joint movement is restricted (Wise, 1975). The measurement of metacarpal descent may therefore be a useful indicator of hand function, particularly in cases of disease or trauma affecting the little finger carpometacarpal joint.
INTRODUCTION Metacarpal descent is a term that has been loosely used to describe the change in the profile of the metacarpal heads that occurs when the hand is moved from a relaxed posture to a clenched fist (Clendenin and Smith, 1984) (Fig 1). Despite the fact that hand movements are extremely complex, simple goniometer measurements are reliable as long as hand position and goniometer placement are standardized (Weiss et al., 1994). With this in mind we have measured metacarpal descent in 90 subjects using a simple, reproducible method. The distal row of carpal bones form a fixed transverse arch, by virtue of their anatomic configurations and ligamentous connections. The ring and little fingers on the ulnar side, and the thumb on the radial side, form two mobile longitudinal arches with varying ranges of motion at the carpometacarpal joints, but the second and third metacarpals are relatively firmly fixed to the distal carpal row (Gurland, 1992). This results in a complex, mobile transverse arch at the level of the metacarpal heads which is shallow when the hand
METHOD Measurements were obtained from 45 men and 45 women, who were stratified equally into the age ranges 20–40, 41–60 and over 60 years. Each subject’s age, hand dominance and occupation (manual or nonmanual) were recorded. Individuals with previous hand pathology were excluded from the study. Since the second and third carpometacarpal joints do not move significantly during the active formation of a fist, a line joining the skyline of the second and third
Fig 1 Metacarpal descent refers to the change in the profile of the metacarpal heads when the hand moves from a relaxed posture (a) to a clenched fist position (b). 289
290
Fig 2 The angle measured with the goniometer is represented here as angle x. It is the angle between a line joining the skyline view of the second and third metacarpals and another line joining the skyline view of the third and fifth metacarpals.
metacarpal heads was used as a reference, from which the descent of the fifth metacarpal head was measured. The position of the fifth metacarpal head was thus documented as an angle, as represented by angle ‘‘x’’ in Fig 2. We defined metacarpal descent as the difference between angle ‘‘x’’ in the relaxed and clenched fist positions. Metacarpal descent was also calculated for the fourth metacarpal by repeating these measurements in relation to the fourth metacarpal head. The relaxed position was standardized by placing the forearm, wrist and palm on a shaped block of wood such that the wrist was held in 251–301 extension by a triangular spur that supported the third metacarpal only (Fig 3). It was ensured that movement of the fourth and fifth metacarpals was not impaired and that the fingers hung freely over the end of the block. The clenched fist position was assessed by asking
Fig 3 The relaxed posture is standardized by placing the hand on a shaped block of wood such that the 3rd metacarpal is supported but the fingers hang freely over the end.
THE JOURNAL OF HAND SURGERY VOL. 27B No. 3 JUNE 2002
the subject to squeeze a softened piece of putty as hard as possible. During a pilot study it was found that subjects often had difficulty forming a natural fist when they knew which part of the hand was going to be measured, but giving them something to squeeze distracted them and allowed them to clench the hand normally. The putty ball was small and soft so that it was squeezed between the fingers when the patient formed a fist and thus did not prevent the joints from fully flexing. Measurements were obtained with a clear goniometer (BaselineTM) so that the profile of the metacarpal heads could be easily seen. One limb of the goniometer was aligned with the skyline view of the second and third metacarpals and the angle ‘‘x’’ was then determined by aligning the other limb of the goniometer with the skyline view of the fourth or fifth metacarpal (Fig 4). A reproducibility study was first carried out to ensure that this method of measuring metacarpal descent was accurate. One subject was measured three times by each of three assessors. The main study was carried out by a single assessor taking all the measurements. Results were analysed using Student’s t-test and analysis of variance. RESULTS Repeated measurements taken by the same observer in the manner described varied by +/ 11. Measurement of the positional angles showed inter-observer differences with a range of +/ 21. The results for the fourth metacarpal are shown in Tables 1 and 2 and those for the fifth metacarpal in Tables 3 and 4. Metacarpal descent of the fifth metacarpal of both hands was significantly greater for women, with a mean of 71 (95% CI, 61–81) as compared with a mean of 41 (95% CI 31–51) for the men (Students t-test, Po0.001). In the men the angle ‘‘x’’ for the fifth metacarpal decreased with age, but the difference between
Fig 4 Measurements are taken with a clear goniometer.
METACARPAL DESCENT
291
Table 1FMean (range) angles (angle ‘‘x’’) between the third and fourth metacarpal heads in men (n=45) Right
21–40 41–60 460 Total
Relaxed
Fist
31 27 25 28
32 30 24 29
(18–40) (17–40) (15–32) (15–40)
Left Metacarpal descent
(26–43) (15–45) (15–40) (15–45)
5 4 6 5
(1–9) (0–10) (0–13) (0–13)
Relaxed
Fist
30 26 25 27
31 28 24 28
(18–40) (18–37) (15–31) (15–40)
Metacarpal descent
(15–40) (20–35) (17–34) (15–40)
3 4 3 3
(0–9) (0–9) (0–6) (0–9)
Table 2FMean (and range) angles (angle ‘‘x’’) between the third and fourth metacarpal heads in women (n=45) Right
21–40 41–60 460 Total
Relaxed
Fist
31 32 31 31
31 29 30 30
(20–42) (21–47) (21–40) (20–47)
Left Metacarpal descent
(22–38) (20–39) (25–44) (20–44)
5 5 4 5
(0–13) (0–14) (0–11) (0–14)
Relaxed
Fist
27 30 30 29
26 30 29 28
(13–37) (25–40) (19–40) (13–40)
Metacarpal descent
(19–35) (22–40) (18–48) (18–48)
5 6 5 5
(0–17) (0–12) (1–11) (0–17)
Table 3FMean (and range) angles (angle ‘‘x’’ ) between the third and the fifth metacarpal heads in men (n=45) Right
21–40 41–60 460 Total
Relaxed
Fist
37 33 30 34
37 33 28 32
(28–46) (22–46) (20–42) (20–46)
Left Metacarpal descent
(27–43) (19–49) (17–42) (17–49)
4 4 6 5
(1–12) (0–9) (1–12) (0–12)
Relaxed
Fist
33 33 29 32
34 32 25 30
(20–42) (21–40) (15–39) (15–42)
Metacarpal descent
(19–40) (22–40) (17–36) (17–40)
4 3 6 4
(0–9) (0–10) (1–10) (0–10)
Table 4FResults of the mean (range) angles in degrees between the third and the fifth metacarpal heads in women (n=45) Right
21–40 41–60 460 Total
Relaxed
Fist
32 37 35 35
34 33 31 33
(23–40) (25–54) (21–44) (21–54)
(23–45) (19–42) (12–48) (12–48)
Left Metacarpal descent 6 8 8 7
(0–20) (1–19) (0–20) (0–20)
angle ‘‘x’’ in the relaxed and fist positions remained the same. Therefore metacarpal descent, as we have defined it, did not change. This decrease in angle ‘‘x’’ was significant for the right fifth metacarpal relaxed and fist positions (ANOVA: Po0.01 and 0.002 respectively) and the fist position on the left (ANOVA: Po0.0002). In contrast, women showed no significant differences between the various age groups for any of the variables tested. Angle ‘‘x’’ for the fifth metacarpal was greater in the dominant hand in the fist position. Mean angle ‘‘x’’ values were 331 (95% CI 311–341) in the dominant hand and 301 (95% CI 291–311) in the nondominant hand (t-test, Po0.005). There was no relationship between metacarpal descent and hand dominance. There were 23 manual workers and 67 non-manual workers. There were no significant differences in angle ‘‘x’’ or metacarpal descent between these two groups.
Relaxed
Fist
30 34 30 31
28 31 28 29
(13–40) (25–45) (10–47) (10–47)
(18–36) (24–42) (15–47) (15–47)
Metacarpal descent 6 7 5 6
(2–13) (1–17) (0–12) (0–17)
Angle ‘‘x’’ for the fifth metacarpal bore no relationship to angle ‘‘x’’ for the fourth metacarpal in either of the hand positions.
DISCUSSION Previous studies have shown up to 401 of flexion/ extension and slight supination at the articulation between the base of the fifth metacarpal and the hamate (Wise, 1975; Clendenin and Smith, 1984). However, we feel that measurement of metacarpal descent is more clinically relevant and reproducible than measurement of flexion/extension at the carpometacarpal joint, especially as this requires specialist instrumentation. The range of motion at any joint is limited by three factors: the shape of the bones themselves, the configuration of the ligaments, and the volume of the soft tissue that lies between the two bones involved. Angle
292
‘‘x’’ and metacarpal descent are therefore dependent on how the above factors affect the little finger carpometacarpal joint, and this probably explains the differences which we found in our population. For example, the difference between the men and women is probably due to differences in ligament laxity. Decreasing values for angle ‘‘x’’ with age, as found in the men, indicate flattening of the hand. This may have been due to arthritic changes affecting the shape of the joints, and may be greater in the men because of the heavier demands placed on their hand joints. Metacarpal descent of the fourth ray is independent of the fifth and thus the position of the fourth metacarpal head is probably dependent on factors related to the ring finger carpometacarpal joint rather than the mobility of the fifth metacarpal. The formation of the distal metacarpal arch is more variable than might be assumed. The measurement of metacarpal descent would be a useful tool in the assessment of disease, trauma or surgery to the little finger carpometacarpal joint, and also in determining the correct position for fusion on the rare occasions when arthrodesis of this joint is indicated. Since the movement of the little finger carpometacarpal joint is what allows the hand to mould itself around objects in power grip, fusion of this joint should not be undertaken unless the level of pain is severe. We would recommend that the position of the fusion should be within the functional arc of carpometacarpal joint
THE JOURNAL OF HAND SURGERY VOL. 27B No. 3 JUNE 2002
movement as this should cause less disability than not being able to place the palm absolutely flat (Gurland, 1992). Therefore in cases where fusion of the little finger carpometacarpal joint is indicated, a knowledge of the normal range for metacarpal descent may be helpful. Acknowledgements Michael Tonkin, Professor of Hand Surgery, Royal North Shore Hospital, Sydney. Medical Photography, Selly Oak. Medical Illustration, Frenchay Hospital. Pete Nightingale, Department of Medical Statistics, Selly Oak.
References Clendenin MB, Smith RJ (1984). Fifth metacarpal/hamate arthrodesis for posttraumatic osteoarthritis. Journal of Hand Surgery, 9A: 374–378. Gurland M (1992). Carpometacarpal joint injuries of the fingers. Hand Clinics, 8: 733–744. Weiss PI, August S, Peters G, Sampalis J (1994). Using the Exos Handmaster to measure digital range of motion: reliability and validity. Medical Engineering and Physics, 16: 323–328. Wise KS (1975). The anatomy of the metacarpophalangeal joints, with observations of the aetiology of ulnar drift. Journal of Bone and Joint Surgery, 57(B): 485–490. Zancolli E. Normal balance of the metacarpophalangeal joint during finger function. In: Structural and dynamic bases of hand surgery. Philadelphia, J.B. Lippincott Company, 1979: 326–336.
Received: 17 November 2000 Accepted after revision: 9 January 2002 Mrs S. C. Tucker, 1 Hillsborough, Main Road, Temple Cloud, Bristol BS39 5BL, UK. E-mail: [email protected] r 2002 The British Society for Surgery of the Hand doi: 10.1054/jhsb.2002.0751, available online at http://www.idealibrary.com on