Minimizes Ulnohumeral Distraction in Unstable Elbows...
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The Supine, Gravity-assisted Overhead Motion Protocol Minimizes Ulnohumeral Distraction in Unstable Elbows Ronak Patel BS 1 , Arthur Lee MD 2 , Mark Schrumpf MD 2 , Dan Choi MS 2 , Kathleen Meyers MS 2 , Timothy Wright PhD 2 , Robert Hotchkiss MD 2 , Aaron Daluiski MD 2 1 University of Texas Medical Branch, Galveston, TX, 2 Hospital for Special Surgery, New York, NY Introduction Early range of motion is important for optimizing the functional outcome in patients with elbow dislo- cations 1 . Despite the agreement that early motion aids in maximizing functional outcomes, there is no consensus on the “best practice” for this method of rehabilitation. Currently, therapeutic rehabilitation is performed with the patient seated in a an upright position, with or without the use of a hinged elbow brace. However, in this position, the weight of the forearm produces a distracting force at the ulno- humeral joint and can lead to subluxation or even redislocation. Wolff and Hotchkiss presented a protocol designed to minimize instability and allow for early motion 2 . In their scheme, gravity was converted from a dis- locating force to a reducing force by having the pa- tient rehab in the supine position with the forearm above the humerus. While this methodology is sup- ported by anecdotal evidence there are no clinical or biomechanical data validating this rehabilitation protocol. The purpose of this study was to determine whether the weight of the forearm in a simulated supine po- sition produces enough force to reduce an unsta- ble elbow joint. We also asked whether the use of a hinged elbow brace is sufficient to counteract the force of gravity. Methods Seven fresh, frozen upper extremity specimens were potted at the mid-diaphysis of the humerus. Elbows were initially imaged in 90 degrees of flex- ion with fluoroscopy in both the upright (forearm below distal humerus) and supine (forearm above distal humerus) positions to document reduction or subluxation of the ulnohumeral joint in the intact state. The specimens were then mounted to a stable testing jig, which allowed for unrestricted full flex- ion and extension of the elbow in the upright and supine positions (Figures 1 and 2). Steinmann pins were placed on the mid-humerus and lateral ole- cranon and mounted with passive retro-reflective optical marker arrays. Figure 1: Upright elbow mounted on testing apparatus Figure 2: Supine elbow mounted on testing apparatus For the control group, elbows were ranged pas- sively in a flexion/extension arc for 30 cycles with the arm in the upright and supine positions. A sham incision was performed, in which a ligament sparing dissection was performed through the skin and common extensor mass, and the upright and supine motions were repeated. The LCL was then sectioned and the test motions were repeated. Each elbow was fitted with a hinged brace and upright testing was repeated. Throughout testing, motion between the humerus and forearm were tracked using a three-camera motion analysis sys- tem. Following testing, fluoroscopic imaging was repeated for the LCL-sectioned state. The ulnohumeral distance was measured at 10-90 degrees of flexion for the control (intact) and three treatment groups (sham, LCL-sectioned, and hinged brace). Comparison was made using two- way repeated measures ANOVA across all flexion angles. For the fluoroscopic imaging, ulnohumeral distraction was normalized to the width of the ulna and then, statistical differences were measured us- ing a simple paired t-test. Results The results showed significantly less distraction at the ulnohumeral joint using supine, gravity-assist- ed range of motion when compared to upright mo- tion. The individual mean distraction values were plotted in a flexion versus distraction plot (Figure 3). The subsequent data discussion is summarized in Table 1. Figure 3: Mean distraction values through 90 degrees of flexion Table 1 With respect to the controls, there was no signif- icant difference between upright intact and sham conditions (mean 0.09 mm; p=0.93) and supine in- tact and sham conditions (mean 0.08 mm; p=0.94). In addition, there was no significant difference be- tween upright intact group and supine intact group (mean 0.07 mm; p=0.95). In the upright position, there was a significant dif- ference between the treatment groups. The up- right LCL-sectioned group showed greater distrac- tion than the upright sham group (mean 3.4 mm; p=0.003). The upright LCL-sectioned group and upright brace group showed significantly greater ulnohumeral distraction than the upright intact group (mean 3.5 mm; p=0.002 and mean 5.1 mm; p<0.001, respectively). Although there was a trend towards increased distraction in the up- right brace group compared to the upright LCL- sectioned group, no significant difference was ob- served (mean 1.6 mm; p=0.15). There were no significant differences in displace- ment across the ulnohumeral joint between any of the supine treatment comparisons. The mean dif- ference between supine sham and supine LCL- sectioned was 0.40 mm (p=0.70). The mean dif- ference between supine intact versus supine LCL- sectioned was 0.32 mm (p=0.76). Finally, the upright LCL-sectioned group demon- strated greater distraction across the ulnohumeral joint than the supine LCL-sectioned group (mean 3.8 mm; p=0.001). However, the greatest distrac- tion across the ulnohumeral joint across all flexion angles was in the upright brace group (mean 5.3 mm, range 1.8-9.8mm). In fluoroscopic analysis, the upright LCL-sectioned group showed statistically significant displacement compared to upright intact (p< 0.001). Conclusions This experiment confirms the concepts illustrated in the supine, overhead, gravity-assisted rehabilita- tion protocol for elbow instability 2 . The motion cap- ture analysis demonstrates a significant difference in distraction between upright and supine, gravi- ty-assisted rehabilitation. In the supine, gravity-as- sisted position, the ulnohumeral joint remains re- duced, with the least amount of distraction across all flexion angles. The overhead motion protocol is conceptually sim- ple and patients can perform this with minimal as- sistance once taught 2 . The effects of gravity are helpful in the overhead, supine position, but detri- mental across the ulnohumeral joint in an upright position (Figures 4 and 5). This is most evident in the effects of the hinged brace, as noted in this study. Among all of the testing groups, the greatest amount of ulnohumeral distraction occurred in the upright position with the hinged brace. The weight of the forearm exerts a distraction force on the ul- nohumeral which is magnified by the weight of the hinged elbow brace. Figure 4: Upright, LCL-deficient elbow showing radio- capitellar joint discontinuity Figure 5: Supine, LCL-deficient elbow showing radio- capitellar joint continuity In conclusion, elbow rehabilitation is a critical as- pect of treatment following complex elbow injuries. The supine, gravity-assisted overhead motion pro- tocol is simple and logical while maintaining con- centric reduction of the ulnohumeral joint. Rehabil- itation in the upright position may cause unneces- sary distraction and possible frank dislocation as gravity imparts a distraction force. Future clinical studies may provide insight into the benefit of this protocol in reducing the chances of joint contrac- ture and redislocation. References & Acknowledgements 1. Anakwe RE, Middleton SD, Jenkins PJ, McQueen MM, Court-Brown CM. Patient-reported outcomes after simple dislocation of the elbow. J Bone Joint Surg Am. 2011;93(13):1220-1226. 2. Wolff AL, Hotchkiss RN. Lateral elbow instability: nonoperative, operative, and postoperative manage- ment. J Hand Ther. 2006;19(2):238-243. Acknowledgements: I would like to sincerely thank my mentors, Dr. Aaron Daluiski and Dr. Arthur Lee, for providing me with guidance and support.
Transcript of Minimizes Ulnohumeral Distraction in Unstable Elbows...
The Supine, Gravity-assisted Overhead Motion Protocol Minimizes Ulnohumeral Distraction in Unstable Elbows
Ronak Patel BS1, Arthur Lee MD2, Mark Schrumpf MD2, Dan Choi MS2, Kathleen Meyers MS2, Timothy Wright PhD2, Robert Hotchkiss MD2, Aaron Daluiski MD2
1University of Texas Medical Branch, Galveston, TX, 2Hospital for Special Surgery, New York, NY
IntroductionEarly range of motion is important for optimizingthe functional outcome in patients with elbow dislo-cations1. Despite the agreement that early motionaids in maximizing functional outcomes, there is noconsensus on the “best practice” for this method ofrehabilitation. Currently, therapeutic rehabilitationis performed with the patient seated in a an uprightposition, with or without the use of a hinged elbowbrace. However, in this position, the weight of theforearm produces a distracting force at the ulno-humeral joint and can lead to subluxation or evenredislocation.
Wolff and Hotchkiss presented a protocol designedto minimize instability and allow for early motion2.In their scheme, gravity was converted from a dis-locating force to a reducing force by having the pa-tient rehab in the supine position with the forearmabove the humerus. While this methodology is sup-ported by anecdotal evidence there are no clinicalor biomechanical data validating this rehabilitationprotocol.
The purpose of this study was to determine whetherthe weight of the forearm in a simulated supine po-sition produces enough force to reduce an unsta-ble elbow joint. We also asked whether the use ofa hinged elbow brace is sufficient to counteract theforce of gravity.
MethodsSeven fresh, frozen upper extremity specimenswere potted at the mid-diaphysis of the humerus.Elbows were initially imaged in 90 degrees of flex-ion with fluoroscopy in both the upright (forearmbelow distal humerus) and supine (forearm abovedistal humerus) positions to document reduction orsubluxation of the ulnohumeral joint in the intactstate.
The specimens were then mounted to a stabletesting jig, which allowed for unrestricted full flex-ion and extension of the elbow in the upright andsupine positions (Figures 1 and 2). Steinmann pinswere placed on the mid-humerus and lateral ole-cranon and mounted with passive retro-reflectiveoptical marker arrays.
Figure 1: Upright elbow mounted on testing apparatus
Figure 2: Supine elbow mounted on testing apparatus
For the control group, elbows were ranged pas-sively in a flexion/extension arc for 30 cycles withthe arm in the upright and supine positions. Asham incision was performed, in which a ligamentsparing dissection was performed through the skinand common extensor mass, and the upright andsupine motions were repeated. The LCL was thensectioned and the test motions were repeated.Each elbow was fitted with a hinged brace andupright testing was repeated. Throughout testing,motion between the humerus and forearm weretracked using a three-camera motion analysis sys-tem. Following testing, fluoroscopic imaging wasrepeated for the LCL-sectioned state.
The ulnohumeral distance was measured at 10-90degrees of flexion for the control (intact) andthree treatment groups (sham, LCL-sectioned, andhinged brace). Comparison was made using two-way repeated measures ANOVA across all flexionangles. For the fluoroscopic imaging, ulnohumeraldistraction was normalized to the width of the ulnaand then, statistical differences were measured us-ing a simple paired t-test.
ResultsThe results showed significantly less distraction atthe ulnohumeral joint using supine, gravity-assist-ed range of motion when compared to upright mo-tion. The individual mean distraction values wereplotted in a flexion versus distraction plot (Figure3). The subsequent data discussion is summarizedin Table 1.
Figure 3: Mean distraction values through 90 degrees offlexion
Table 1
With respect to the controls, there was no signif-icant difference between upright intact and shamconditions (mean 0.09 mm; p=0.93) and supine in-tact and sham conditions (mean 0.08 mm; p=0.94).In addition, there was no significant difference be-tween upright intact group and supine intact group(mean 0.07 mm; p=0.95).
In the upright position, there was a significant dif-ference between the treatment groups. The up-right LCL-sectioned group showed greater distrac-tion than the upright sham group (mean 3.4 mm;p=0.003). The upright LCL-sectioned group andupright brace group showed significantly greaterulnohumeral distraction than the upright intactgroup (mean 3.5 mm; p=0.002 and mean 5.1mm; p<0.001, respectively). Although there wasa trend towards increased distraction in the up-right brace group compared to the upright LCL-sectioned group, no significant difference was ob-served (mean 1.6 mm; p=0.15).
There were no significant differences in displace-ment across the ulnohumeral joint between any ofthe supine treatment comparisons. The mean dif-ference between supine sham and supine LCL-sectioned was 0.40 mm (p=0.70). The mean dif-ference between supine intact versus supine LCL-sectioned was 0.32 mm (p=0.76).
Finally, the upright LCL-sectioned group demon-strated greater distraction across the ulnohumeraljoint than the supine LCL-sectioned group (mean3.8 mm; p=0.001). However, the greatest distrac-tion across the ulnohumeral joint across all flexionangles was in the upright brace group (mean 5.3mm, range 1.8-9.8mm).
In fluoroscopic analysis, the upright LCL-sectionedgroup showed statistically significant displacementcompared to upright intact (p< 0.001).
ConclusionsThis experiment confirms the concepts illustratedin the supine, overhead, gravity-assisted rehabilita-tion protocol for elbow instability2. The motion cap-ture analysis demonstrates a significant differencein distraction between upright and supine, gravi-ty-assisted rehabilitation. In the supine, gravity-as-sisted position, the ulnohumeral joint remains re-
duced, with the least amount of distraction acrossall flexion angles.
The overhead motion protocol is conceptually sim-ple and patients can perform this with minimal as-sistance once taught2. The effects of gravity arehelpful in the overhead, supine position, but detri-mental across the ulnohumeral joint in an uprightposition (Figures 4 and 5). This is most evident inthe effects of the hinged brace, as noted in thisstudy. Among all of the testing groups, the greatestamount of ulnohumeral distraction occurred in theupright position with the hinged brace. The weightof the forearm exerts a distraction force on the ul-nohumeral which is magnified by the weight of thehinged elbow brace.
Figure 4: Upright, LCL-deficient elbow showing radio-capitellar joint discontinuity
Figure 5: Supine, LCL-deficient elbow showing radio-capitellar joint continuity
In conclusion, elbow rehabilitation is a critical as-pect of treatment following complex elbow injuries.The supine, gravity-assisted overhead motion pro-tocol is simple and logical while maintaining con-centric reduction of the ulnohumeral joint. Rehabil-itation in the upright position may cause unneces-sary distraction and possible frank dislocation asgravity imparts a distraction force. Future clinicalstudies may provide insight into the benefit of thisprotocol in reducing the chances of joint contrac-ture and redislocation.
References & Acknowledgements1. Anakwe RE, Middleton SD, Jenkins PJ, McQueenMM, Court-Brown CM. Patient-reported outcomesafter simple dislocation of the elbow. J Bone JointSurg Am. 2011;93(13):1220-1226.
2. Wolff AL, Hotchkiss RN. Lateral elbow instability:nonoperative, operative, and postoperative manage-ment. J Hand Ther. 2006;19(2):238-243.
Acknowledgements: I would like to sincerely thankmy mentors, Dr. Aaron Daluiski and Dr. Arthur Lee,for providing me with guidance and support.
