Pinch and Grasp (Key-Pinch and Hook Grip)

The most commonly performed surgeries to obtain key-pinch and hook grip are:

Wrist Extension – If the person does not have adequate wrist extension, Brachioradialis (BR) to Extensor Carpi Radialis Brevis (ECRB) is performed prior to any surgery for pinch reconstruction.

Key-Pinch and Hook Grip – Extensor Carpi Radialis Longus (ECRL) to Flexor Digitorum Profundus (FDP). This is a synergistic transfer in which dorsiflexion of the wrist potentiates the effects of the transfer. The amplitude of excursion provides strong flexion of the fingers into the palm. Brachioradialis (BR) is also transferred to Flexor Pollicis Longus (FPL).

The aim of these transfers is to provide mass finger flexion for grasp and independent thumb flexion for key-pinch against the side of the middle phalanx of the index finger. Adjustment of tension in these transfers is also completed (Lamb & Chan 1983).

Author Year


Research Design


Total Sample Size

Methods Outcome
Coulet et al., 2018




Population: Mean age=34 yr; Gender: males=23, females=8; Time since injury: 7.3 yr; Level of injury: tetraplegia=31; Severity of injury: groups 1 to 5 of Giens international classification of tetraplegia levels.

Intervention: Participants received active (n=18) or passive (n=22) key pinch reconstructive surgery using a technique that either preserved the carpometacarpal (CMC) joint or required arthrodesis. Outcome measures were assessed at baseline and an average of 7.3 yr following surgery.

Outcome Measures: Grip strength; Key pinch opening; Stability.

1.     Active key pinch strength was significantly higher than passive key pinch strength (p<0.05) in patients who underwent CMC arthrodesis. 2.     No significant differences in key pinch strength were observed in passive key pinch surgery patients with and without CMC (p>0.05).

3.     Active key pinch reconstruction with CMC arthrodesis hinders key pinch opening similarly to passive key pinch reconstruction. No significant difference was observed (p>0.05).

4.     No significant differences in key pinch stability were observed for either surgical technique (p>0.05).

Mohindra et al., 2017




Population: Mean age=42.2 yr; Gender: males=9, females=3; Time since injury: 6 mo; Level of injury: C6 – C8; Severity of injury: not reported.

Intervention: Key pinch was restored using Brachioradialis to Flexor Pollicis Longus transfer and hook using Pronator Teres to Flexor Digitorum Profundus transfer. Outcome measures were assessed at baseline, six mo and a final follow up time averaging 26 mo post surgery.

Outcome Measures: Key pinch and hook grip (Modified Lamb and Chan score).

1.     Prior to surgery the average value for key pinch and hook grip was 0 kg; Following surgery, the average value was 1.67 kg for key pinch and 2.58 kg for hook grip at final follow up.

2.     A significant increase in key pinch (p=0.0010) and hook grip (p=0.0015) was observed between 6 and 26 months demonstrating that gains achieved are maintained over time.

3.     The Modified Lamb and Chan score revealed good to fair outcome in 75% of patients.

Forner-Cordero et al., 2003


Retrospective Follow-up

NInitial=15; NFinal=14

Population: Age: 20-62 yr; Level of injury: C4-C7; Time since injury: 15-239 mo.

Intervention: Surgical reconstruction.

Outcome Measures: Increased hand movement and strength, Activities of Daily Living (ADL), Patient’s satisfaction, Fulfillment of patient’s expectations, Surgical complications.

1.     Strength: key-pinch strength average of 17.2 kPa (5-50 kPa); grasp strength average 18.8 kPa (3-45 kPa).

2.     No relation found between the ADL test and the key pinch strength (p=0.7976) or grasp strength (p=0.6948).

3.     Modification of ADL questionnaire; excellent (3) 21.4%; good (7) 50.0%; fair (2) 14.3 %; poor (2) 14.3%. Scores ranged from 54-122 points.

Meiners et al., 2002 Germany

Case Series

NInitial=24; NFinal=22

Population: Age: 21-57 yr; Gender: males=21, females=3; Time since injury: 9-59 mo.

Intervention: Surgery.

Outcome Measures: Activities of Daily Living (ADL) questionnaire, Satisfaction Survey, Key grip, Lateral force grip.

1.     Operative interventions on the tetraplegic hand brings gains in cylindrical and lateral grip and improvement in ADL.

2.     Subjective acceptance is high.

3.     Complication rate is high.

4.     Long duration of treatment.

Lo et al., 1998


Case Series


Population: Level of injury: C5-6; Time since injury: ≥1 yr.

Intervention: Surgery.

Outcome Measures: Key pinch strength; Minnesota rate of manipulation; Satisfaction with surgery.

1.     All reported they would have surgery again.

2.     Key pinch strength in non-op limbs was 1.0±1.3 kg, in surgically treated arms it was 1.2±1.1 kg.

3.     Minnesota rate of manipulation: non-operative limbs were 1.50±0.25 sec, post-operative limbs was 2 min 56 secs±1 min 56 sec.

Failla et al., 1990


Case Series


Population: Age: 9-58 yr; Level of injury: tetraplegia.

Intervention: Surgery.

Outcome Measures: Key pinch, Grip strength, Activities of Daily Living (ADL).

1.     No statistical results reported-eight patients interviewed, five completed questionnaires.

2.     Conclusion-transfer of brachioradialis tendon provides key pinch and grip of sufficient quality to improve the ADLs in patients with loss of flexion of the thumb and fingers.

Gansel et al., 1990


Case Series


Population: Age: 20-47 yr.

Intervention: Surgery.

Outcome Measures: Range of motion (ROM); Finger flexion; ADL performance.

1.     No statistical analysis reported.

2.     Passive range of motion (ROM) of the elbow and wrist remained unchanged post-surgery. Functional active flexion of the fingers was gained in 10/11 subjects.

3.     Improved performance of Activities of Daily Living (ADL) was reported.

Rieser & Waters 1986


Case Series


Population: Mean age: 23.6 yr; Mean time since injury: 6.2 yr.

Intervention: Surgery.

Outcome Measures: Subjective rating of power.

1.     Self-assessment questionnaire results indicated: power decreased since surgery in all patients.
Kelly et al., 1985


Case Series


Population: Age: 19-60 yr; Gender: males=17, females=7; Level of injury: group III=3(normal shoulder control, elbow flexion, radial wrist extensors), group IV=11 (same as group III with functioning FCR, PT & triceps, weak fingers), group V=7 (intrinsic hand muscle paralysis), group VI=4 (incomplete paralysis); Time since injury: 1-17 yr; Follow-up time: 1-17 yr.

Intervention: Surgery.

Outcome Measures: Self reported surgery satisfaction and function; Key pinch; Grasp; Palmar pinch.

1.     Seven extremities had had post deltoid to triceps transfer before opponensplasty; 24 patients, 11 (46%) had bilateral opponensplasty.

2.     Thirty-five opponensplasties were done. 22 flexor tendon transfers were done for voluntary grasp and then opponensplasty.

3.     Fourteen patients (22 extremities) evaluated.

4.     Subjects reported that they would have the operation again (95% of the extremities) and had improved function (91%).

5.     One patient reported that function was unchanged; one was dissatisfied. Overall value of key pinch 35 extremities was 1.47±1.29 kg (mean± SD).

6.     Grasp measured in 20 extremities; 2.81±2.89 kg (mean±SD) (range trace to 10kg).

7.     Palmar pinch; 9 of 20 extremities (45%) achieved palmar pinch (1.04±1.02 kg; mean±SD) (range 0.20-3.0 kg). Palmar pinch achieved in 17% of the extremities in group III, 71% in group IV, and 33% in group V.

Colyer & Kappelman 1981


Case Series


Population: Age: 16-36 yr; Time since injury: 4 mo-18 yr.

Intervention: Surgery.

Outcome measures: Self-reported satisfaction; Hand function; Key grip strength.

1.     6/8 subjects were evaluated. Subjects indicated they were pleased with the surgery.

2.     Hand function tests indicated an improvement (16-49% improvement).

3.     5/6 subjects showed key grip strength remained constant.

Wangdell et al., 2014




Population: Mean Age: 38.8 yr; Gender: males=10, females=1; Level of Injury: C4=1, C5=2, C6=6, C7=1, Unspecified=1.

Intervention: Patients who underwent hand surgery between February 2009 to March 2011 participated in an interview in order to discuss the individual experiences of regained hand control after grip reconstruction. Interviews were conducted at 12 mo post-surgery at the patients’ home clinic. A grounded theory approach was adopted for analyzing the interviews.

Outcome Measures: Self-reported mood.

1.     The patients’ responses revealed three phases of recovery; initiating activity training, establishing hand control in daily life, and challenging dependence.

2.     During phase one, patients reported experiencing mood swings (both positive and negative) such as fascination, eagerness and fear, encouragement from rehabilitation staff, and practicing their hand control in real life situations with beneficial results keeping them motivated. Patients transitioned into phase 2 after gaining confidence and belief in trying new activities.

3.     At phase 2, establishing hand control in daily life, patients reported diverse learning strategies with some patients using trial and error whilst others planned their activities ahead of time but patients consistently approached one task at a time. Patients also reported that new abilities and tasks required time and effort.

4.     External factors in phase 2 also reported that home environments for practicing activities were more beneficial than clinics and that positive feedback maintained high motivation levels. A theme emerged in that patients transitioned to phase 3 after developing confidence and self-efficacy in hand control.

5.     At phase 3, patients reported the use of celebrations to promote motivation and self-affirmation, changing habits and roles to improve awareness, trusting and using their new skills to become more independent, adapting their physical environment to accommodate their new skills, and that social peers had to allow the patients to use their new skills.

6.     After phase 3, a theme emerged of higher independence with patients stating several examples of autonomy.

Wangdell et al., 2013




Population: Mean Age: 38.8 yr; Gender: males=10, females=1; Level of Injury: C4=1, C5=2, C6=6, C7=1, Unspecified=1.

Intervention: Patients who underwent hand surgery between February 2009 to March 2011 participated in an interview in order to discuss the individual experiences of regained hand control after grip reconstruction. Interviews were conducted at least 7-17 mo post-surgery.

Outcome Measures: Self-reported physical ability and psychological mood.

1.     The patients’ responses revealed three key areas that enhanced recovery; physical, psychological, and self-efficacy.

2.     Self-efficacy was considered an important element in developing independence, especially when gripping and grasping objects. Self-efficacy was also revealed to be a motivator for further improvements and learning new skills.

3.     Ability to perform more activities such as making food, picking up objects, opening/closing doors were among the practical aspects that enhanced independence. Participating in social activities (e.g. eating at a restaurant, sports/games, shopping), increasing levels of activity and decreasing dependence on assistance, and being less restricted by physical environments (i.e. improvising in environments not suited to their needs) were common themes for increasing independence.

4.     Psychological aspects that enhanced independence post-surgery included being able to regain privacy and perform self-care tasks alone, and developing a sense of manageability in controlling their own actions which both increased feelings of self-esteem and a decrease in “psychologically bad days”. Further patients reported a sense of identity and a sense of equality ( work, as a caregiver to children, etc).