Quick T.J and Brown H. 2018

Subjective assessment of successful re-innervation leading to return of elbow flexion.


1.1                Overview

Oberlin et al (1994) described a nerve transfer to renervate elbow flexion and thus improve arm function. It is performed with the aim of returning sufficient elbow flexion force to lift weight. Traditionally, surgical success is measured by the return of power and assessed by Maximal Peak Force (MPF) but is this outcome, in isolation, significant to patients?

This study has been designed to explore whether peak power is a parameter that is meaningful to the patient. Patient satisfaction with outcome is often complicated and can include aspects such as: what an individual anticipated to achieve and what has made a difference to their day to day function.

To the author’s knowledge there has been no published data on subjective assessment and in particular, the patient’s opinion of their outcome following an Oberlin procedure.

1.2                Method

Study participants were recruited from the hospital database and comprised of 18 patients who were at least 24 months post double Oberlin transfer. The study received institutional ethical approval and informed consent was given by all participants.

A mixed methods approach was adopted whereby the cohort underwent a quantitative assessment (maximal peak force (KgF) and completed a subjective questionnaire regarding the patient’s view of their individual recovery.

This study set out with the null hypothesis (H0) that patient satisfaction with outcome would be directly related to the level of recovery of elbow flexion force (as measured by peak power).

Ethical approval was gained from the NHS ethical board after IRAS application.


1.3                Results

Despite Maximal Peak Force (MPF) being the most commonly assessed outcome following nerve transfer surgery is shown to not be a responsive or representative outcome measure to reflect the patient experience of muscle re-innervation. There was no significant correlation between the commonly used outcome measure of peak power and the patient’s perception of the impact on their life (R 0.488 with a non-significant level of evidence p= 0.108).

Patients significantly under-estimate the outcome of surgery as assessed by a comparison of the subjective assessment and objective measurement of elbow flexion peak force. There is significant correlation between the patients’ assessment of their current function and expectation attainment. Whereas, objectively measured force was strongly correlated with patients’ assessment of difference (R=0.619 P=0,006).

Patient satisfaction levels were universally high with 100% of respondents reporting that they would both recommend the operation to others and undergo the same procedure if they were back in the same situation. As all patients had regained power of elbow flexion as was the aim of the operation this is not surprising. Of the cohort 11/16 (61%) rated the impact as having had made a huge difference to them.

It is thus demonstrated that patients do notice the difference of having greater peak force but do not translate that into their assessment of impact.

1.4                Conclusion

Satisfaction with this nerve transfer operation to renervate elbow flexion shows no correlation with how much force (KgF) against gravity the biceps muscle can provide. When correlation was sought between a range of subjective assessment questions and force outcome there was some degree of face validity when using peak force as an outcome measure. However, this study begins to provide some evidence to support the necessity of a multimodal assessment to reflect a complicated picture of motor recovery. There is no related literature in the field of nerve injury on which to reflect.


8.2                  Introduction

Loss of active elbow flexion creates a considerable deficit in function. Activities such as hand to mouth for feeding and hand to midline to allow for independent dressing are commonly reported functional goals. Nerve injuries to the upper trunk, lateral cord and musculocutaneous nerve can all result in the loss of active biceps contraction.


8.3                  Measurements of surgical outcome

Traditionally, clinicians have used maximal peak force (measured by MRC grade) as a primary outcome measure. Hand Held Dynamometry (HHD) has been identified as a method to give a valid and continuous numerical value to force outcome assessment. A previous study within our institute examined the maximal force outcomes following Oberlin Transfer using HHD (Quick et al. 2016). The benefits of ease of use and utility within a clinical environment were also highlighted. The results produced a continuous metric of KgF normally distributed around 7.2KgF for this patient group (Quick et al 2016). Data was consistent with a previous study which  reported strength to be around 1/3 that of the uninjured contralateral limb (Carlsen et al. 2011). HHD therefore seems to be a useful method to measure peak force outcome within this cohort.

Within the clinic environment it is common for many postoperative patients to report pain, fatigue and difficulty placing the arm to be limiting factors to their everyday life. Anecdotally the weight they can lift in a single maximal contraction is seldom raised as an issue. Nevertheless, in the literature it is peak force that is almost universally used to assess outcome of muscle renervation procedures.

The World Health Organisation (WHO) developed the International Classification of Functioning, Disability and Health (ICF) as a framework for measuring health and disability at both individual and population levels (WHO, 2001). In this framework both muscle function and the person’s perceptions are considered alongside their ability to participate in everyday activities. This reflects the change in modern day healthcare where patient perceptions and satisfaction are considered with equal status to a clinician’s “objective” outcome. Recent analysis of outcome following nerve injury has endorsed the use of patient-reported outcomes and functional assessments (Novak et al. 2009, Ahmed-Labib et al. 2007, Kitajima et al. 2006).  A literature search on subjective and patient reported outcome measures (PROMs) of Oberlin transfer or nerve transfer produced no results. This represents a significant void in the literature.

Information regarding patient reported outcome in Oberlin transfer could provide a framework for clinicians to better tailor their assessment towards patient experience. Furthermore, the assessment of patient experience may thus provide information on how to improve patient satisfaction with their care.


4:                 Aims, objectives & Methodology

4.1                Study question:

  • Is there a positive correlation between an individual’s reported satisfaction with their outcome and the amount of elbow flexion strength that is regained following renervation surgery?

4.2                Aims:

  1. Identify a cohort of Oberlin transfer patients with documented MRC grade 4 recovery of elbow flexion at greater than 2 years post-operatively.
  2. Design and administer a questionnaire to assess patient perception, expectation and satisfaction with surgical outcome.
  3. Carry out a standardised peak force assessment using HHD for comparison with the subjective findings from the questionnaire.

4.3                Objectives:

  1. To use a mixed methods format to gain information on the impression patients had of their outcome.
  2. To collect patients’ assessment of their own peak power and whether they thought they had attained their original expectation of outcome.
  3. To assess if patient satisfaction correlated with the degree of muscle strength of elbow flexion or attainment of preoperative expectation.
  4. To assess a cohort of patients to assess whether difference within attainment of peak power outcome is reflected in satisfaction

5                  Hypotheses

Null Hypothesis (H0): Patient assessment of satisfaction in their outcome is directly related to their recovery of force (as measured by Maximal Peak Force).

Primary Hypothesis (H1): Patient assessment of satisfaction in their outcome is not directly related to their recovery of force (as measured by Maximal Volitional Force).


6                  Materials and Methods

Ethical approval was gained from the NHS ethical board after IRAS application.

 REC reference: 16/LO/0623  
 IRAS project ID:  202847  


The hospital database was examined to identify patients who were at a point greater than 24 months following Oberlin nerve transfer. These individuals were then further reviewed against the inclusion and exclusion criteria which included documented recovery of a minimum of MRC grade IV within their medical records (full criteria is outlined in Table 8.1). Sixty-two patients were identified as being eligible to participate in the study. All participants were contacted by post with a letter to invite them to complete an online questionnaire and to attend a clinical review. If no response was received after one month a second invitation letter was sent. A total of 18 patients were recruited in the study; of these 12 participants attended for a force outcome assessment.



Inclusion Exclusion
Oberlin/double Oberlin transfer – treated with standard post-operative regimen

>24 months post surgery

Documented activity of elbow flexion of grade 4 MRC or above from clinical notes

Adult 18+

Oberlin transfer <24months post surgery

Oberlin transfer >24 months post surgery with MRC <3

Oberlin transfer >24 months post surgery proceeded to free functioning muscle transfer

Child (0 -18 years)

Figure 1:

Inclusion / Exclusion criteria.

The time period of 24 months post surgery was chosen by consensus agreement between the researchers as a suitable period for full motor recovery to have occurred. Clinically, after this time, there is very little evidence of further renervation. All patients underwent a standard regimen of post operative rehabilitation; an initial immobilisation period of 6 weeks followed by a milestone driven process of passive mobilisation, active movement and strengthening when signs of renervation returned.

A mixed methods approach was adopted whereby a subjective qualitative questionnaire focussing on satisfaction and participant’s opinions relating to their motor recovery was compared to an objective quantitative maximal force outcome measured using a HHD (Biometrics Ltd, Cwmfelinfach Wales).


6.1                Stage 1. Subjective data collection

The qualitative questionnaire was designed by the researchers (TQ, HB and KJ) utilising a mixed approach of discrete, framework supported and Likert questions to pose questions around the concepts of interest (impression of current function, expectation of function, minimal accepted expectation of function, impression of change and impact of change). These were then developed into an online ‘Google forms’ survey (Google Inc. Mountain View, California, United States). The questionnaire commenced with an animated video of an isolated elbow flexion motion to focus the mind of the responder. Additional text was provided to direct respondents to solely consider elbow flexion as they answered the questions. In order to gather as much information as possible tick box, Likert scales and free text entry functions were utilised.


Figure 2:

Screen grab from Google Forms assessment tool questionnaire.


The questionnaire focused on various elements of recovery to explore different dimensions of patient experience. The themes included patient/participants’ assessment of their current force of elbow flexion, a percentage assessment of their overall elbow function, their hopes preoperatively, their minimum expectation and their impression of change following the renervation and the impact this change has had. Finally, standard frequently used questions, such as those in the Friends and Family test (NHS England 2014), guided questions towards the subjects’ perception and finally satisfaction of their outcome (for example; would they recommend the surgery to others? and would they chose to have the surgery again?).


6.2                Stage 2. Objective Quantitative data

In order to anchor the answers to the questionnaire 12 of the 18 patients (67%) agreed to attend an assessment of their maximal peak force MPF. This assessment was carried out by 2 experienced therapists (HB and KJ). The assessment protocol utilises a HHD (Biometrics Ltd, Cwmfelinfach Wales) and is described in a previous publication (Quick et al. 2016).  During this assessment; participants were asked to relate and disclose the maximal weight in kilograms that they believe that they can lift using their biceps muscle (i.e. elbow flexion). These were related to everyday objects (such as: 2kgs is approximately a four-pint bottle of milk and 5kgs approximately the weight of a vacuum cleaner). The validity of the test is shown by inter-observer R= 0.958 and intra-observer reliability R=0.941 of the test is documented in figures 8 and 9.








  Question: Question focus:                         Quantification
Q1 How much are you currently able to bend your elbow? Current function/ Subjective assessment Discrete; statements describing MRC
Q2 Before surgery I would have realistically hoped to…  

Pre operative Expectation/ Hope

Discrete; statements describing MRC
 Q2b ..be able to lift the following with operated arm alone. Discrete KgF with anchor statements
Q3 Before surgery I would have agreed to go ahead only if I could have realistically expected to… Minimum Expectation Discrete; statements describing MRC
 Q4 A normal elbow is one which is pain-free, has full range of movement, normal strength and allows you to do what you feel your elbow should allow you to do this is scored at 100% (10/10). 0/10 is no function. How would you score your elbow?  



Percentage assessed  function with definition of range
Q5 How much do you think that your elbow function has improved since your surgery? Impression of Change/ Improvement Likert scale with each point defined  0-6
Q6 What difference has this operation made to you? Impression of Impact/Difference Likert scale with end points defined  0-6
Q7 Would you recommend this operation to somebody else (who has had the same injury as you) to improve their ability to bend their elbow?  



Binary Y/N

Q8 With your current knowledge, if we were to take you back in time to before the operation would you say yes to the offer of an operation to gain movement in your elbow?  



Binary Y/N

Figure 3.

Summary of focus of subjective asessment tool questions.



7                    Results:

18 patients (15 Male and 3 Female) consented to participate in stage one of the study (qualitative questionnaire). Of these, 12 (10 males and 2 females) proceeded to stage two (quantitative muscle force assessment). The mean age of the participants was 45 years (27- 69 years old). Right hand dominance (RHD) was reported in 16 participants with the remaining 2 being left handed (LHD). Injured dominant side 10, non-dominant 8 (dominant 5, non-dominant 7) The days since injury at time of assessment were an average of 2704.17 (range 642-7227). Full results and demographics are presented in Figure 8.4.



Participant Gender Age Injured side Injured side Injury Op date Peak 





1 M 47 L ND Avulsion C5/6 27/08/14 7.73 7
2 M 27 L ND Avulsion C5

Rupture C6

02/10/15 16.27 7
3 M 27 L ND UT neuroma 23/01/15 8.92 5
4 F 69 L ND UT neuroma 17/09/10 6.33 5
5 M 52 L ND UT neuroma 30/09/11 6.83 5
6 M 44 L ND C5 Avulsion

C6 neuroma

23/05/14 9.57 1
7 M 51 R D Avulsion C5/6 15/06/09 12.3 4
8 F 47 R D Tumour

upper trunk

06/07/98 3.12 1
9 M 36 R D Avulsion C5/6 27/08/10 5.36 4
10 M 53 R D MCN Rupture

Humeral fracture

23/08/96 10.38 5
11 M 43 L D Avulsion C5/6/7 +/-8 17/10/14 4.65 3
12 M 50 L ND Avulsion C5/6/7 09/09/09 7.21 5
13 M 41 R D Avulsion C 5/6 01/09/14   6
14 M 51 L ND Avulsion C5/6/7 11/02/15   0
15 M 29 R D Avulsion C5/6 31/01/14   2
16 M 26 L D Avulsion C5/6

Rupture C7/8

05/03/08   5
17 F 45 R D MCN iatrogenic 20/11/15   6
18 M 59 R D MCN Rupture

Humeral fracture

15/04/15   7

Figure 4:

Research Subjects demographics & information (first n-=12 have force data) In the text the numbers quoted first (and highlighted in bold) are the group of n=12 who both completed the questionnaire and underwent an objective assessment of their peak force.



 Stage 1. Subjective Outcomes.

7.1                Q1. How much are you currently able to bend your elbow.

All subjects by selection criteria had recovered MRC grade 4.

Figure  5

.Bar chart representing answers to Q1. “How much are you currently able to bend your elbow?”


Current force assessment n=18 MRC

Equivalent (/5)



I am unable to bend my elbow unless I use another part of my body to bend it 1 or 2 1
I am able to bend my elbow a bit by itself but would not be able to lift any weight 3 3
I am able to bend my elbow by itself and would be able to lift some weight 4 11
My elbow can bend to what I consider to be just less than full power 5 3

Figure  6:

Tabulated results for  Q1. How much are you currently able to bend your elbow?


Commentary on Q1: 14/18 (78%) identified that the restoration of innervation to the elbow flexors has allowed them to lift some weight. This corresponds with at least MRC grade IV classification. 4/18 (22%) report that the return of power is insufficient to lift a weight.

7.2                Q2a. Before surgery I would have realistically hoped to…

Figure 7:

Bar chat representation for results for Q2a. Before surgery I would have realistically hoped to …


Before surgery I would have realistically hoped to…(Expectation) MRC Equivalent (/5) No.(/18)
Be unable to bend my elbow unless I use another part of my body to bend it 1 – 2 3
Be able to bend my elbow a bit by itself but would not be able to lift any weight 3 3
Be able to bend my elbow by itself and able to lift some weight 4 10
Be able to bend my elbow to what I consider to be just less than full power 5 2

Figure 8:

Tabulated representation for results for Q2. Before surgery I would have realistically hoped to …


Q2b. Before surgery I would have realistically hoped to lift the following with the operated arm alone.

Before surgery I would have realistically hoped to lift the following with the operated arm alone



Equivalent (/5)



50gs (approx. the weight of a chocolate bar) 4 1
100gs (approx. the weight of a tube of tooth paste) 4 0
300gs (approx. the weight of a small tin of beans) 4 1
500gs (approx the weight of a small bottle of water) 4 2
1kg (approx the weight of a litre bottle of water) 4 2
2kgs (approx the weight of a 4 pint bottle of milk) 4 4
3kgs (approx the weight of 3 litre tin of paint) 4 0
5kgs (approx the weight of a vacuum cleaner) 4 1
10kgs (approx the weight of a lawn mower ) 4/5? 2
15kgs (approx the weight of 12 bottles of wine ) 5 2

Figure 9:

Tabulated representation for results for Qb2. Before surgery I would have realistically hoped to … (n=1 “Depends on how much I have trained the muscles” n=1 did not answer                                                                                n=1 “I can lift a heavy weight but not using biceps”

Table 10:

Bar chat representation for results for Q2b. Before surgery I would have realistically hoped to …


Commentary on Q2a and b:

The findings from Q2a MRC questions show that 3/18 (17%) patients hoped to achieve the equivalent of MRC grade V (normal or just less than normal – accepting 95-100% being near normal and classically classified as MRC 5/5). 11/18 (61%) expected MRC 4/5 power, 3/18 (17%) hoped for MRC 3/5 and finally, 1/12 (8%) expected MRC 2/5 or less.

In Q2b a level of internal dissonance is demonstrated as 15 patients stated they would have MRC 4+ power. (n=3 either did not answer or stated they didn’t use biceps to lift a heavy weight or they stated “it depends on how much I have trained the muscle”. This distribution tri-modal and has an overall mean resonance as 4 KgF the mode is 2kgF.


7.3                Q3. Before surgery I would have agreed to go ahead only if I could have realistically expected to…

Figure 11:

Bar Chart representation for results for Q3. Before surgery I would have agreed to go ahead only if I could have realistically expected to.





I would only have gone ahead with surgery if I could have realistically

expected  to… n=18






Be unable to bend my elbow unless I use another part of my body to bend it. 0 1
Be unable to bend my elbow unless I use another part of my body to bend it BUT be able to feel the muscle responding as if it wanted to work. 1 – 2 1
Be able to bend my elbow a bit by itself but would not be able to lift any weight 3 4
Be able to bend my elbow by itself and would be able to lift some weight 4 12
Be able to bend my elbow at full power 5 0

Figure 12:

Tabulated results for Q3. Before surgery I would have agreed to go ahead only if I could have

realistically expected to…


Commentary on Q3:

This question aimed to assess a minimal expectation level (what the patient expected as a minimum) in order to give consent to surgery. 12/18 (67%) expected as a minimum to achieve MRC grade IV recovery. This is well within the boundaries of any series of Oberlin outcome results. It represents a real and attainable expectation.

It is interesting that 2/18 (11%) would have been happy with no visible functional improvement and 6/18 (23%) would have been happy to proceed if they could have, as a minimum, expected no functional improvement.



Review of Q1, Q2 & Q3:

MRC Grade Cohort Actual*


(Clinically assessed)

Cohort self Assessed

Present Outcome

Cohort Realistic Expectation of


Cohort Minimum Expectation of Outcome
1/5 1
2/5 1 3 1
3/5 3 3 4
4/5 18 11 10 12
5/5 3 2

Figure 13:

Tabulated results for Q1, Q2& Q3. To demonstrate the number of the cohort in each category of MRC force (* this cohort was purposefully selected to be MRC grade 4)


>/ =4/5

Population** actual Cohort actual* Cohort assessed Cohort expected Cohort minimum
80% 100% 78% 67% 67%


Figure 14:

Tabulated results to demonstrate the percentage of the cohort for each category with function (MRC>/=4) (* this cohort was selected to be MRC grade 4) (**expectation of an MRC 4+ outcome following Oberlin transfer in non selected standard population)


Table 13 demonstrates the shifting distribution of where the cohort currently believes themselves to be (despite a purposeful sample of MRC grade IV being selected for the study). The table shows where the cohort had hoped they would be (expectation of outcome) and the spread of expectations which they would have considered as a minimum to consent to surgery. Table 8.14 displays these same concepts as a percentage of the cohort at or above MRC 4 (a commonly quoted outcome in the literature). 

In summary, when Qs 1,2 and 3 are reviewed in relation to one another the following can be asserted:

The (retrospectively assessed) expectation or hope of the procedure was for 78% greater than, or equal to MRC grade IV. This is in line with published rates of outcome from Oberlin procedure and thus represents a realistic expectation.

However only 14/18 (78%) stated that they thought they had attained MRC grade IV despite being purposely included in the study based on a documented clinical record of grade IV being achieved.

This suggests that the remaining 22% did not achieve their expected level of strength or force (a Negative Expectation Attainment). It may therefore be surmised that subjective impression of change is less than the objective observer may think.

Two thirds of participants expected as a minimum to attain their expectation: The minimum expectation assessment relates 12/18 hoping for function (elbow flexion >/=MRC IV) and expectation relates the same figure 12/18 hoping to gain at least some function to lift weight.

  • Interestingly 2/12 patients’ minimum expectation was no functional return whereas 3 stated they expected they would get no functional return. i.e. 2 subjects were happy to go ahead with surgery even if they got no function and one was happy to go ahead only if they could as a minimum expect a flicker of activity but actually realistically expected to get no function.

However, 33% predicted they would not achieve their expectation of the benefit of the operation (a negative predicted personal experience: NPPE).

Objective Anchor comparison with Q2b

12 participants attended for stage 2 (objective force assessment) the force they generated in objective testing was compared with what they predicted the maximal weight that they could lift with their affected arm.

Actual current function: (Objective force assessment data) n=12:(7.73/16.27/8.92/6.33/6.83/9.57/12.30/3.12/5.36/10.38/4.65/7.2 KgF) mean 78.22 (range3.12-16.27 ) SD 3.59

Patient assessed current function (Subjective assessment anchor question)  “At 2 years post nerve transfer surgery I am able to lift”:

The same n=12: (2/15/2/0/0.5/2/depends/10/0.5/0/1/2) Kg mean 3.5 (range0-15 SD 4.94)

These are two differing groups with differing means:

A paired samples analysis n=10 (2 predicted values missing thus excluded) shows a difference of -4.1Kg between the mean (predicted being lower than actual) with a 95 CI between -7.1 and -1.1) t-3.044 and significance (2 tailed) of 0.014. That is to say; the average subjective assessment of our patients was to attain a lesser outcome than demonstrated they could lift, or we can say there was an average over-attainment or a positive expectation mismatch.

Figure 15:

a paired data analysis of Expectation mismatch- blue circles are the value the patients prediction (subjective assessment) and in Green the actual or (objectively) observed KgF of elbow flexion









7.4                Q4. A normal elbow is one which is pain-free, has full range of movement, normal strength and allows you to do what you feel your elbow should allow you to do this is scored at 100% (10/10). 0/10 is no function. How would you score your elbow? [SPONEA] N=18

Figure 16:

Bar Chart  results to demonstrate the SPONEA outcome.


A normal elbow is one which is pain-free, has full range of movement, normal strength and allows you to do what you feel your elbow should allow you to do this is scored at 100%

% 10 20 30 40 50 60 70 80 90 100
N 1 2 1 1 2 6 2 3 0 0


N=18 mode 5 mean 4.3 (range0-8) SD 2.14

Figure 17:

Tabulation of reponses to the SPONEA question.


Commentary on Q4:

When the subjective SPONEA is compared with the MPF scores there is a definite relationship between the two as demonstrated by a Pearson’s correlation of 0.604 with a two tailed significance of 0.008.

Figure 18:

Funnel Scatter plot of SPONEA against Objectively assessed peak force with a linear best fit surrounded by 95% CI.


7.5                Q5. How much do you think that your elbow function has improved since your surgery?

  1. No change (or condition has got worse).
  2. Almost the same, hardly any change at all.
  3. A little better, but no noticeable improvement in my function.
  4. Somewhat better, but the change has made no noticeable improvement in my function.
  5. Moderately better with a slight but noticeable change in my function.
  6. Better with a definite improvement that has made a real and worthwhile difference in my function.
  7. A great deal better with a considerable improvement that has made all the difference in my function.

Figure  19:

Bar chart results to demonstrate impression of change since surgery. Plot of overall satisfaction Likert Scale no better (1) – a great deal better (7)- mode = 5 mean= 4.78

Q5. How much do you think that your elbow function has improved since your surgery?

0-    No change

1-    Almost the same hardly any change at all.

2-    A little better, but no noticeable improvement in my function.

3-    Somewhat better, but the change has made no noticeable improvement in my function.

4-    Moderately better with a slight but noticeable change in my function.

5-    Better with a definite improvement that has made a real and worthwhile difference in my function.

6-    A great deal better with a considerable improvement that has made all the difference in my function

change 0 1 2 3 4 5 6
n 0 1 0 2 3 7 5


Figure 20:

Tabulated results to Q5.


Commentary on Q5:

The mode of 5 represents another facet of the patient experience – “moderately better with a slight but noticeable change” and with 12/18 rating the change as noticeable or better.




7.6                Q6a.what difference has this made from 0 (no difference) – 5 (a huge difference)

Figure 21:

Bar chart results to Q6. Demonstrating the subjective impact of the re-innervation

(0)- no difference to (5) a huge difference



Q6 what difference has this made from 0 (no difference) – 5 (a huge difference)

0-    No change

5-    A huge difference

Difference 0 1 2 3 4 5  
N 1 1 0 0 6 10  


Figure 22:

Bar chart results to demonstrate distribution of difference made 5: huge difference to 0: no difference. N=18 Mean 4.22/5, Mode 5/5 SD 1.309.


Characterisation of groups by assessment of impact

                                                N                                              Mean                Std. Deviation   Std. Error Mean

force of those with impact 5/5                           8                                              9.9600                                     4.44762           1.81573

force of those with less than 5/5                        8                                              7.4150                                     3.43892           1.40393

Comparison of groups by assessment of impact

                                                                                                                        t                       n                      Sig 2t               Mean Diff          95% CI

force of those with impact 5/5                           5.485               8                      p=.003*    9.96000       5.2925-14.6275

force of those with less than 5/5                        5.282               8                      p=.003*     7.41500                   3.8061-11.0239

Figure 23:

Comparison of groups by assessment of impact. Two groups were created those who deemed the impact 5/5 (a huge difference and those who did not; the peak Force they developed were compared in KgF.



Free text entry following question on degree of impact of recovery.

“Can move my arm where as before it was useless.”

“Can still do my job as a heavy plant engineer”

“Because my arm was completely useless before the surgery yes I would like it to be better and continue to try to improve it!”

“I went from a totally non functional arm to Semi-functional.”

“My arm was totally dead. The ability to move the elbow and hold or lift light items is a great comfort. It also offers some worthwhile useful functions when cooking, dressing or carrying things.”

“I had no function in my arm and limited movement. No I have some and it is getting stronger”

“No difference at all really, but to be fair it was a long time ago and it was a long shot to get my elbow moving again!”

“Prior to my operation I had very limited use of my arm. I can not be sure that the operation has been the sole reason for progress, I do believe ‘other’ muscles compensate.”

“Although not perfect, to one that doesn’t know, it all looks and operates quite normal though my arm tires very quickly.”

“Before the operation I had no movement at all in my left arm and now I have quite a bit of muscle contraction. So I think that it has definitely made a huge difference.”

“Prior to my op, I had no biceps / triceps function – now both work to a reasonable / useful level”

“Living through the progress”

“Prior to operation the whole left arm from shoulder to hand did not have any function. along with tendon transfers & nerve surgery this operation has transformed my daily living.”

“As a PE teacher and a right arm injury the flexion of my arm is essential to work.”

“Before was unable to move now I have full movement with not many restrictions in what I can do. I would recommend it to anyone”

These qualitative data provides texture to the qualitative subjective experience where the impact is rated as a Mean 4.22/5, Mode 5/5 SD 1.309.

Commentary on Q6a and b:

There is significant population difference when the means of those individuals who stated the operation has made a 5/5 huge difference (n=6, 9.96 KgF) with those who graded it as less than this (n=6, 7.42 KgF). However, 16/18 of the respondents graded the impact as 4/5 or greater therefore this difference is less clinically relevant. The respondent who graded the impact as 0/5 scored an MPF of 3.12KgF. The overall satisfaction with the impact is 4.78/5 satisfaction. Over 50% (10/18) scored 5/5. The majority (11/12) reported a 4/5 or 5/5 difference.


7.7                Q7. Would you recommend it to another with the same problem?

18/18 (100%) responded Yes

7.8                Q8. Given the chance would you undergo the same treatment again?

18/18 (100%) responded Yes

7.9    Stage 2. Quantitative Outcomes.

Patient’s re-innervated force outcomes (as measured with a continuous measure of Kilogram Force; KgF, with a HHD) were normally distributed (mean = 8.2KgF SD = 3.6).



Figure 23:

Histogram of the spread of objectively assessed force (KgF) as measured with a HHD. Line of best fit depicting MRC Grade 4 subset distribution. Mean 7.2 kgf (3 to 15.5; SD 3.3). (Best fit line as calculated by SPSS software)

Figure 24:

Table demonstrating multi input bi-variate analysis of two tailed significance of Pearsons correlation


When subjective outcomes are compared to Maximal Peak Force (MPF) there is poor correlation between the majority of the qualitative data and the quantitative outcome. However, there was a link between two of the subjective assessments and peak force, but neither had a very strong correlation (r= 0.631 and 0.694) Figure 24.

  • Improvement/impression of change (Q5) had a correlation of 0.694 at a significance level of 0.12
  • The SPONEA (Q4) correlated to a similar level (0.631) with a higher significance of 0.028.

The strongest correlations within the collective of subjective assessments were between:

  • Hope (Q2.) showed a correlation of 0.59 (at a sig of 0.01) with minimal expectation
  • The SPONEA Q4 correlated with several measures as well as the peak objective force:
  • Current function: 0.604 at the 0.008 level.
  • Assessment of improvement (Q5.): (0.519 sig 0.27)
  • Impression of impact/difference (Q6.): (0.560 sig 0.16)
  • Assessment of Improvement (Q5) and the assessment of the difference this made (Q6) correlate to 0.889 (with a significance of 0.000)
  • Expectation mismatch (*EM) (Q123) and current function; (0.817 sig 0.004) but, as EM is a derivative of current function, (current function – expectation = EM) this may be likely a product of the relationship rather than demonstrate a causal relationship.

The findings therefore enable us to reject the null hypothesis. The results demonstrate that satisfaction with nerve transfer surgery for elbow reanimation is unrelated to the peak force attainment.

This study demonstrates that the patient related impact of restoring active elbow flexion is unrelated to the amount of force restored. However, the subjective satisfaction for Oberlin nerve transfer is high across the range in force (8.22Kg SD 3.595).

There is a disparity seen between the standard objective outcome assessment of muscle function (as assessed by clinicians) compared to the objective experience and patient’s perception of the strength and use of their arm. Peak force is not a responsive or representative outcome measure to reflect the patient experience of muscle re-innervation. This reinforces that the objective assessment of peak force is not reflective of the breadth of subjective factors that influence a patient’s perception of their outcome. However, the study does indicate that maximal peak force does show some correlation with the patient’s impression of change and some improvement in function. Patients do not appear to relate peak power in an unrelated or unqualified way to their outcome


8                  Discussion

This study aimed to evaluate the patient’s perspective of their return of muscle function following Oberlin nerve transfer. To the author’s knowledge this is the first study to do this. The standard outcome for this operation has been peak force and these data suggest this is a poor measure of outcome with little validity to patient experience.

Patient reported outcomes are growing in popularity and the strengths and weaknesses of these are well discussed. In designing this battery of questions a multidimensional approach was used in order to try to be as reflective of the many layers and aspects of patient experience as possible. Health Transition Questions (HTQs) do this by directly asking patients to assess whether they consider their health or functioning to have changed in comparison with a previous time point, often pre intervention, pre surgical intervention. Particularly when short measures are employed or single global questions are grouped with HTQs that probe experiences of adverse events or side effects. For example, to assess the accuracy and sensitivity of measures designed to specifically probe PROs in Orthopaedic surgery, treatment satisfaction questions have been posed alongside direct HTQs as an external anchor (Dawson et al. 2008; 2014).

In a recent review (Lloyd et al. 2014) suggest that there are a number of benefits associated with combining a simple set of questions to elicit patients’ assessments of the outcomes of hospital treatment. Most importantly, it directly identifies outcomes relevant to the individual patient, which can differ between patients and also from what clinicians believe to be important to measure. The results of surveys using this type of question may feed into improvements in clinical practice more easily. There is also evidence in the literature that asking patients to assess the outcome of their treatment has face validity. Indeed, Jaeschke et al. (1989) concluded that in the absence of a gold standard measure external global ratings represent a credible meaning of change in a new measure.  This is shown in the widespread use of such questions, particularly transition questions as external anchors to assess the performance of other PROMs. This methodology allows identification of outcomes relevant to the patient. Dawson et al. (2010) found that patient satisfaction with surgery poorly correlated with clinician ratings at follow up, and therefore provided more evidence of the difference between patients’ and clinicians’ perceptions of which aspect of outcome to rate as important  (Jenkinson et al. 2002; Wright et al. 1994).

In designing the questions for our data collection tool we utilised a spread of question type, methodology and subject areas. We combined closely defined parameter questions and Likert methods; to bring together investigations on subjective measures of expectation, attainment, function and satisfaction. It has been shown that, questions that interrogate patients as to the extent to which an intervention has helped improve their health, or that explore the direct experience of treatment may be less subject to bias than satisfaction questions (Pathak 1981) Likert-type satisfaction rating scales provide a high degree of precision (Fitzpatrick et al. 1998). It is also known that in order to to avoid the problems of using a single global measure which is likely to reflect numerous features of the treatment received, and be closely related to the quality of the care received- satisfaction and assessment of the outcomes of treatment should be measured multi-dimensionally (Cleary & McNeil 1988). In addition, multi-item scales generally yield more score variability, and higher reliability and validity score than single items measures (Ware et al. 1978).

In selecting our anchor objective assessment we rely on our previous work which identified the use of a hand held dynamometer (HHD) as reliable method to measure peak force of elbow strength in this cohort (Quick et al. 2016, Maricq et al. 2014). A previously published pilot study outlined the protocol for use and discusses its weakness (Quick et al. 2016).

A cohort of patients was identified who met the inclusion criteria. They had undergone nerve transfer surgery and successfully gained reanimated elbow flexion to MRC grade IV at 24 months post operatively. A mixed-methods approach was adopted as it seemed best suited to provide a holistic overview and gain the maximum amount of information to answer the research question.

Stage 1 of the study utilised a structured questionnaire to provide insight into patient experience, expectations and satisfaction levels with surgical outcome. Several aspects of the qualitative information were of particular interest:

Firstly, in asking patients to assess their current function (when they had been selected as being able to lift some weight) only 14/18 (78%) identified that the restoration of innervation to the elbow flexors has allowed them to lift some weight (this corresponds with at least MRC grade IV classification). Thus; 4/18 (22%) failed to recognise the functional ability of their renervated muscle.

A literature review to identify experience in assessing subjectively rated force (in PubMEd and Google Scholar) for the strings (“Muscle strength” AND “subjective assessment”) and (“Muscle power” AND  “subjective assessment”)  (“Muscle power” AND “patients assessment”) (“Muscle force” AND “experience”) (“Muscle assessment” AND  “experience”) (“Muscle assessment” AND “subjective” AND “objective”) identified no pertinent studies.

The authors’ discussions with colleagues identified a systematic review on shoulder outcome named “Patient reports of the outcomes of treatment: a structured review of approaches’ by Lloyd ( 2014) highlighted, as one of its themes, force assessment in shoulder outcomes. From here two studies were identified which showed assessment of force (Smith et al. 2006; Yang et al. 2015)

Yang (Yang et al. 2015) identified one hundred and  twenty consecutive patients at their 1-year postoperative visit after shoulder arthroplasty and captured patient assessed, home-based questionnaire. Within this study the patients lifted bags filled with water up to a mean weight of 2.72Kg. This test was designed to test range of motion under differing loads not peak force.

Smith (Smith et al. 2006) assessed that “physicians rated … strength as being closer to normal [in comparison with the subjective assessment]”. This study was an assessment of a consecutive series of 68 patients encounters who were at the point of assessment at an average of 51 months following shoulder surgery (range 6 months – 22 years). The assessment was framed as a rating of ‘the overall strength of the shoulder” and was graded with a 10 point Likert scale (with non linear ‘advisory statements’) such as -normal was 1,  Good- 3,  Fair- 4.5 , Poor 6.5, very poor – 8 and Paralysis – 10.


They had patients complete this assessment by colouring in a circle and a similar assessment was preformed by the treating surgeon or one of the junior medical staff. The two groups graded the force – physicians 3.75 +/-  2.3 and the patients 4.43 +/- 2.3. The mean difference is assessed as being -0.68 with the 95% intervals as being -1.12 and -.025).

This does appear to be an area of research which will require more attention. It is however important not just to assess what the disparity is between subjective and objective assessment of force (as shown in Figure 15)  but to investigate why. These data have shown an overall pessimistic assessment of elbow flexion assessment both in terms of global MRC (anchored statement scale) and the KgF (anchored statement scale). This may represent a lack of internal validity of the measure- that the cohort do not fully understand how to assess their elbow flexion force, but it is considered that it more likely represents that muscle peak force is not a quantity which represents patient experience.

When patients were asked to disclose their realistic expectation of surgery (Q2) 78% reported an expected outcome of MRC >/= 4/5. As previously discussed, the published data regarding the outcome of Oberlin transfer in terms of peak force is considered to be MRC grade IV in an average of 80% of cases (Sedain et al. 2011; Goubier & Teboul 2007; Ray et al. 2011). This suggests that the expectations of patients with regards to their likely outcome are being well met.  Furthermore, it may act as an indicator that patients have been appropriately informed during the consent process with realistic outcomes portrayed. It is interesting to note that patient expectations are closely associated with their ratings of satisfaction with medical care (Kravitz 2016; Williams et al. 1995) and it may be an effect of treatment in a specialist centre that the patient cohort receives multimodal education and a common message to prepare expectations.

The inclusion criteria of the study purposely selected individuals who had documented recovery of at least grade IV elbow flexion. Conversely, 4/18 (22%) participants reported that the return of power was insufficient for them to lift weight. Furthermore, one respondent reported that they were unable to bend their elbow without assistance. This demonstrates some conflict with the clinical documented outcome of grade IV MRC. There is the possibility that these outliers may have misunderstood the nature of the question. Equally their answers display the potential mismatch between clinical assessment of force and patient perception of outcome. In order to assess the demonstrated variance between the predicted and observed force for the Q3b it is noted that there have strangely been few studies to assess patient’s assessment of their own force as above. Several questions highlighted that it is not just the recovery of elbow flexion force that is important to the patient. This is illustrated keenly in the free text responses only two patients use the word ‘elbow’ the vast majority refer to their ‘arm’ as a wider assessment.


Question 4 focussed on the SPONEA which was an adaptation of the SPONSA. The SPONSA – the Validation of the Stanmore percentage of normal shoulder assessment is a validated outcome measure (Noorani et al. 2012) for shoulder function now widely used  (George, Malal et al. 2014, Torrance et al. 2017). Our modification is asking the same question “A normal shoulder is one which is pain-free, with a full range of movement, normal strength and stability, and allows you to do what you feel your shoulder, if normal, should allow you to do. A normal shoulder is scored as 100 percent, while a completely useless shoulder is scored as 0 percent. Overall where would you rate your shoulder between 0 and 100 percent, at this present time” but replacing the word shoulder for elbow. This a novel subjective measure of elbow function introduced specifically for this study and whilst it takes face validity from the SPONSA it is not yet formally fully validated. However, the SPONEA was able to demonstrate a significant correlation with Maximal Peak Force (two tailed significance p= 0.008) suggesting that it may have some clinical utility as an assessment tool. This is not a surprise though as integral to the question is a concept of ‘normal strength’ and thus it would be expected to be reactive to differences in the force of elbow flexion. Further studies are required to validate its use but this may be a valid tool  to assess outcomes for the Oberlin.

Most patients reported that the surgery had made a worthwhile or huge difference to their life with 16/18 (89%) rating it as providing a 4/5 or 5/5 difference to their lives. Patient satisfaction is perhaps the most important criterion of success. This concept  is well recognised in the service industries, though remains something of a nebulous concept in clinical care (Hamilton et al. 2013). Patient reported outcomes measures (PROM) difference reporting for many orthopaedic musculoskeletal procedures have high ratings and varicose vein and breast reduction surgery.

In a large cohort (n=4709) of prospectively followed cohort with 95% take up Hamilton (Hamilton et al. 2013) patients were also asked to rate their overall satisfaction with their operated hip or knee on a four-point scale (very satisfied, satisfied, unsure or dissatisfied). Data on satisfaction with five specific facets of surgical outcome were obtained with the following questions, answered on a six-point scale (excellently, very well, well, fairly, poorly, don’t know): (1) ‘How well did the surgery relieve the pain in your affected joint?’; (2) ‘How well did the surgery increase your ability to perform regular activities?’; (3) ‘How well did the surgery allow you to perform heavy work or sport activities?’; (4) ‘How well did the surgery meet your expectations?’ We then asked our patients to indicate their satisfaction with the care they received at the hospital with the question (5) ‘rate your overall hospital experience’ using the response scale; excellent, very good, good, fair, poor or unknown. We also asked further two questions that enquired as to the patient’s attitude towards further surgery: (1) ‘Would you have this operation again if it were required on another joint?’ and (2) ‘Would you recommend this operation to someone else?’ (Possible responses: definitely yes, possibly yes, probably not, certainly not or not sure) Overall patient satisfaction was predicted by: (1) meeting preoperative expectations (OR 2.62 (95% CI 2.24 to 3.07)), (2) satisfaction with pain relief (2.40 (2.00 to 2.87)), (3) satisfaction with the hospital experience (1.7 (1.45 to 1.91)), (4) 12 months Oxford scores (1.08 (1.05 to 1.10)) and (5) preoperative (0.95 (0.93 to 0.97)) Oxford scores. These five factors contributed to a model able to correctly predict 97% of the variation in overall patient satisfaction response.

The two final questions focussed on satisfaction in the context of whether the patient would undergo the same procedure again and whether they would recommend it to someone else. 100% of respondents said yes to both. The answers to these questions demonstrate the subjective impression of the impact of the surgery. When reviewed alongside the free text answers to Question 6 the strong positive results can be visualised. Several participants’ report that their arm was “useless” prior to surgery and many comments also focus on a return to “function” or “semi-function” within the arm. Furthermore one participant reported that they get comfort from being able to grasp and lift light items. It may be surmised that in cases of life changing injury, satisfaction or impression of change tools may not be sensitive to the multidimensional and bio-psychosocial effects of injury and therefore struggle to guide improvements in outcome measurement Stage 2 of the study was to compare the most commonly used current assessment technique (of maximal peak force) correlated with the information gained in stage 1. The results again correlated with other literature (Quick et al. 2016; Carlsen et al. 2011)  with an average of 8.2KgF (SD 3.6). When compared to the findings of Stage 1 and when considered in relation to the research question maximal peak force does demonstrate some face validity to the patient as an outcome measure; but only as part of a much more complicated picture. The findings of this study indicate that patients determine the impact of an intervention by how much they feel they are able to do.  When the answers from the questions regarding what difference the surgery had made to their lives were compared to actual force outcome there was no significant correlation (0.488 with a non-significant level of evidence p= 0.108).


9                  Study limitations

There are various limitations within this study. Firstly, assessment of self reported function was solely focussed on motor recovery. Although recognised as important considerations for holistic management; Features such as Quality of life (QoL), pain and body image were not incorporated. This streamlined the study and reduced the scope of the commentary limiting the possibility of the full breadth of subjective experience from being expressed.

The retrospective nature of the study is not ideal; it was conceived as a pilot to inform the design of future prospective data capture studies. A 30% (18/62) follow up rate undoubtedly raises concerns of outcome bias however this response rate for trauma patient follow up is quite usual and representative of a typical trauma population (Leukhardt et al. 2010; Crandall et al. 2014). Commonly cited difficulties when arranging long term follow up with this cohort typically refer to patients who are young, mobile and wish to return to normal life. Future studies may be advised to establish prospective data collection methods to enhance follow up rates.

Patients were given the opportunity to remain anonymous or disclose their identity when completing the questionnaire. All participants chose to discard anonymity. In order to avoid any further bias the researchers ensured that any treating clinicians were absent during the data collection process and that the entry of data was not overseen.

Finally, this study adapted the wording from the SPONSA (a validated shoulder assessment) to create an elbow specific SPONEA. Although the SPONSA has been shown to be a legitimate measure for use with shoulder patients. It has not yet been assessed if it will have the same validity when modified for different joints (Noorani et al. 2012). However, the findings of this study suggest that the SPONEA may be a useful indicator of patient reported outcome for elbow reanimation. Considering the results of this investigation, future studies to validate the use of the SPONEA are recommended.

 10                Conclusion

In summary, muscle is a complex organ and its functions beyond strength alone should be considered during assessment of outcome following a denervated period. Proprioception, functional co- contraction and mechanisms of smooth and controllable recruit-ability are some of a myriad of aspects of muscle renervated function which have been identified as limiting factors to recovery post injury. Asking the patient’s opinions with regards to outcomes will enable clinicians to specifically measure valid improvements that exceed the minimal clinically important difference for that outcome. If we are to, quite acceptably, used peak power to inform studies on outcome it should be with one eye to the other dimensions of muscle function and global patient function. The results of this study have provided insight into the spectrum of motor outcomes. Ongoing studies of a qualitative nature such as focus group discussions are recommended to further direct care.