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Arm rotated medially with supination - the ARMS variant: description of its surgical correction.

Nath RK, Somasundaram C, Melcher SE, Bala M, Wentz MJ - BMC Musculoskelet Disord (2009)

Bottom Line: Mallet score increased by an average of 5.2 (p < 0.05).Overall forearm position was not significantly changed from an average of 5 degrees to an average of 34 degrees maximum apparent supination after both shoulder rotation and forearm rotation corrective surgeries.In reality, the neutral-appearing position of the hand indicates a fixed supination posture of the forearm in the face of a medial rotation contracture of the shoulder.

View Article: PubMed Central - HTML - PubMed

Affiliation: Texas Nerve and Paralysis Institute, Houston, TX, USA. drnath@drnathmedical.com

ABSTRACT

Background: Patients who have suffered obstetric brachial plexus injury (OBPI) have a high incidence of musculoskeletal complications stemming from the initial nerve injury. The presence of muscle imbalances and contractures leads to typical bony changes affecting the shoulder, including the SHEAR (Scapular Hypoplasia, Elevation and Rotation) deformity. The SHEAR deformity commonly occurs in conjunction with Medial Rotation Contracture (MRC) of the arm. OBPI also causes muscle imbalances at the level of the forearm, that lead to a fixed supination deformity (SD) in a small number of patients. Both MRC and SD will cause severe functional limitations without surgical intervention.

Methods: Fourteen OBPI patients were diagnosed with MRC of the shoulder and SD of the forearm along with SHEAR deformity during a 16 month study period, with eight patients available to long-term follow-up (age range 2.2 - 18 years). Surgical correction of the MRC was performed as a triangle tilt or humeral osteotomy depending on the age of the child, after which, the patients were treated with a radial osteotomy to correct the fixed supination deformity. Function was assessed using the modified Mallet scale, examination of apparent supination and appearance of the extremity at rest.

Results: Significant functional improvements were observed in patients with surgical reconstruction. Mallet score increased by an average of 5.2 (p < 0.05). Overall forearm position was not significantly changed from an average of 5 degrees to an average of 34 degrees maximum apparent supination after both shoulder rotation and forearm rotation corrective surgeries.

Conclusion: The simultaneous presence of two opposing deformities in the same limb will visually offset each other at the level of the wrist and hand, giving the false impression of neutral positioning of the limb. In reality, the neutral-appearing position of the hand indicates a fixed supination posture of the forearm in the face of a medial rotation contracture of the shoulder. Both of these deformities require surgical attention, and the presence of concurrent MRC and SD should be monitored for in OBPI patients.

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Apparent supination in OBPI patients with medial rotation contracture. A. A 9-year-old male patient with MRC showing a lack of supination ability of the left arm due to the medial rotation position of the upper arm. B. An 18-year-old female patient with MRC and SD (ARMS variant) showing apparently normal supination of the left arm (Patient 5). Note the position of the left elbow crease as compared with the right side.
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Figure 2: Apparent supination in OBPI patients with medial rotation contracture. A. A 9-year-old male patient with MRC showing a lack of supination ability of the left arm due to the medial rotation position of the upper arm. B. An 18-year-old female patient with MRC and SD (ARMS variant) showing apparently normal supination of the left arm (Patient 5). Note the position of the left elbow crease as compared with the right side.

Mentions: The MRC is a major cause of shoulder deformity in children with OBPI, requiring surgery in more than one third of patients whose injury did not resolve spontaneously [1]. The term SHEAR (Scapular Hypoplasia Elevation And Rotation) deformity has been used to describe the ultimate bony consequence of the muscular fibrosis, and is potentially relevant to the majority of OBPI patients exhibiting MRC [2-4]. The most clearly visible manifestation of the SHEAR deformity is elevation of the scapula[4]. Scapular elevation has also been observed to be further complicated by a forward rotation which occurs along with an abnormal twisting of the clavicle, tilting the entire acromio-clavicular plane forward and causing impingement of the acromion upon the humeral head. [4-6]. Progression of the SHEAR deformity, due largely to unrelieved MRC, may contribute to or further exacerbate the deleterious effect of the MRC on glenohumeral development [7-9]. This is visible as a persistent elbow-bent posture, shortening of the arm and awkward lateral rotation [5,10] (Figure 1A). The act of supination in patients with MRC alone will typically only generate apparent rotation to the neutral position or less, because medial rotation at the level of the shoulder masks the true supination ability (Figure 2A).


Arm rotated medially with supination - the ARMS variant: description of its surgical correction.

Nath RK, Somasundaram C, Melcher SE, Bala M, Wentz MJ - BMC Musculoskelet Disord (2009)

Apparent supination in OBPI patients with medial rotation contracture. A. A 9-year-old male patient with MRC showing a lack of supination ability of the left arm due to the medial rotation position of the upper arm. B. An 18-year-old female patient with MRC and SD (ARMS variant) showing apparently normal supination of the left arm (Patient 5). Note the position of the left elbow crease as compared with the right side.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2664782&req=5

Figure 2: Apparent supination in OBPI patients with medial rotation contracture. A. A 9-year-old male patient with MRC showing a lack of supination ability of the left arm due to the medial rotation position of the upper arm. B. An 18-year-old female patient with MRC and SD (ARMS variant) showing apparently normal supination of the left arm (Patient 5). Note the position of the left elbow crease as compared with the right side.
Mentions: The MRC is a major cause of shoulder deformity in children with OBPI, requiring surgery in more than one third of patients whose injury did not resolve spontaneously [1]. The term SHEAR (Scapular Hypoplasia Elevation And Rotation) deformity has been used to describe the ultimate bony consequence of the muscular fibrosis, and is potentially relevant to the majority of OBPI patients exhibiting MRC [2-4]. The most clearly visible manifestation of the SHEAR deformity is elevation of the scapula[4]. Scapular elevation has also been observed to be further complicated by a forward rotation which occurs along with an abnormal twisting of the clavicle, tilting the entire acromio-clavicular plane forward and causing impingement of the acromion upon the humeral head. [4-6]. Progression of the SHEAR deformity, due largely to unrelieved MRC, may contribute to or further exacerbate the deleterious effect of the MRC on glenohumeral development [7-9]. This is visible as a persistent elbow-bent posture, shortening of the arm and awkward lateral rotation [5,10] (Figure 1A). The act of supination in patients with MRC alone will typically only generate apparent rotation to the neutral position or less, because medial rotation at the level of the shoulder masks the true supination ability (Figure 2A).

Bottom Line: Mallet score increased by an average of 5.2 (p < 0.05).Overall forearm position was not significantly changed from an average of 5 degrees to an average of 34 degrees maximum apparent supination after both shoulder rotation and forearm rotation corrective surgeries.In reality, the neutral-appearing position of the hand indicates a fixed supination posture of the forearm in the face of a medial rotation contracture of the shoulder.

View Article: PubMed Central - HTML - PubMed

Affiliation: Texas Nerve and Paralysis Institute, Houston, TX, USA. drnath@drnathmedical.com

ABSTRACT

Background: Patients who have suffered obstetric brachial plexus injury (OBPI) have a high incidence of musculoskeletal complications stemming from the initial nerve injury. The presence of muscle imbalances and contractures leads to typical bony changes affecting the shoulder, including the SHEAR (Scapular Hypoplasia, Elevation and Rotation) deformity. The SHEAR deformity commonly occurs in conjunction with Medial Rotation Contracture (MRC) of the arm. OBPI also causes muscle imbalances at the level of the forearm, that lead to a fixed supination deformity (SD) in a small number of patients. Both MRC and SD will cause severe functional limitations without surgical intervention.

Methods: Fourteen OBPI patients were diagnosed with MRC of the shoulder and SD of the forearm along with SHEAR deformity during a 16 month study period, with eight patients available to long-term follow-up (age range 2.2 - 18 years). Surgical correction of the MRC was performed as a triangle tilt or humeral osteotomy depending on the age of the child, after which, the patients were treated with a radial osteotomy to correct the fixed supination deformity. Function was assessed using the modified Mallet scale, examination of apparent supination and appearance of the extremity at rest.

Results: Significant functional improvements were observed in patients with surgical reconstruction. Mallet score increased by an average of 5.2 (p < 0.05). Overall forearm position was not significantly changed from an average of 5 degrees to an average of 34 degrees maximum apparent supination after both shoulder rotation and forearm rotation corrective surgeries.

Conclusion: The simultaneous presence of two opposing deformities in the same limb will visually offset each other at the level of the wrist and hand, giving the false impression of neutral positioning of the limb. In reality, the neutral-appearing position of the hand indicates a fixed supination posture of the forearm in the face of a medial rotation contracture of the shoulder. Both of these deformities require surgical attention, and the presence of concurrent MRC and SD should be monitored for in OBPI patients.

Show MeSH
Related in: MedlinePlus