Does a minimal invasive approach reduce anterior chest wall numbness and postoperative pain in plate fixation of clavicle fractures?

Patients

The inclusion criteria for the study cohort comprised patients with an age between
18 and 75 years having sustained an acute displaced fracture of the clavicle (delay
of trauma-repair 14 days), necessitating plate fixation. Written informed consent
was obtained from each patient. The individuals shown in the figures gave their written
permission to publish their images. All fractures were classified according to the
Orthopaedic Trauma Association 9] (OTA). Preoperative standard radiographs of the clavicle (anterior-posterior perpendicular
to cassette and anterior-posterior 30 degree angle cephalad) were performed. Patients
with a history of any other pathology such as preexisting chest wall numbness, cervical
root symptoms, former surgery of the affected shoulder or chest wall, neurological
or sensorial deficits or signs of neuropathy were excluded from the study. The study
protocol was approved by the local ethics committee (Ethics Committee of the medical
faculty, Klinikum rechts der Isar, Technical University of Munich, Germany; study
number 5536/12). Between March 2014 and August 2014, 24 displaced fractures of the
clavicle in 24 patients (22 men, 2 women) with a mean age of 38.2?±?14.2 years (22–78
years) were enrolled in the study (see Table 1). Open reduction and internal fixation (ORIF) was performed by using the Synthes®
LCP superior anterior clavicle plate in each patient. According to the OTA classification
9] 2 patients had a type B1.2, 5 a type B2.2, 7 a type B2.3, 5 a type B3.1, 1 a type
C1.1 and 4 a type C1.2 fracture.

Table 1. Patient demographics and outcomes

Surgical technique

All patients underwent ORIF in beachchair position with the affected arm in a mobile
position. The decision regarding the surgical approach was based upon the surgeon’s
individual preferences, all MOP procedures were done by the senior author (CK). Conventional
open plating was performed by two equally experienced upper extremity surgeons (SH,
PB). Surgery was done in general anesthesia, perioperative antibiotic prophylaxis
was administered either using a 2^nd generation cephalosporin or gentamycin. In all patients a standard implant (locking
compression plate (LCP), superior anterior clavicle plate, Depuy-Synthes®, 4528 Zuchwil,
Switzerland) was used. The duration of the surgical procedure was measured from the
time of skin incision until the time of skin suture.

Conventional open plating

A transverse skin incision was made along the long axis of the clavicle. The length
of the skin incision depended on the estimated plate length according to the fracture
pattern. After sharp dissection of the platysma, the soft tissue covering the clavicle
was extensively separated from the bone to expose the fracture zone and to prepare
the estimated plate position. The fracture hematoma was debrided. To gain anatomical
reduction the fracture was temporarily reduced using reduction forceps. The position
was checked using fluoroscopy. Lag screws (Depuy-Synthes®, 4528 Zuchwil, Switzerland)
were used to fixate wedge fragments. The plate was superiorly centered onto the clavicular
shaft and after confirmation of correct plate positioning in fluoroscopy, screw holes
were consecutively drilled.

Mini open plating

In the minimal invasive technique, a small transverse skin incision not extending
the length of the fracture zone was made (Fig. 1a?+?b). After sharp dissection of the platysma and the underlying soft tissue, the
fracture was sparingly exposed to debride the fracture hematoma. Anatomical reduction,
temporary fixation and fixation of wedge fragments were analogically performed to
the COP group (Fig. 1c). The plate was inserted through the small skin incision and superiorly centered
onto the clavicular shaft. After confirmation of correct plate positioning in fluoroscopy,
screw holes were consecutively drilled. Two additional stab incisions were performed
to drill the medial and lateral plate holes (Fig. 1d?+?e).

Fig. 1. Operation technique in a fracture of the clavicular midshaft (OTA B2.3; patient 11,
MOP group)). (a) anatomical landmarks and estimated skin incision; (b) skin incision to expose the fracture; (c) anatomical fixation of the wedge fragments by using two lag screws; (d) fixation of the plate; (e) stab incisions to drill the medial and lateral plate holes; (f) skin suture

Standardized postoperative protocol

The postoperative analgesia included metamizole and a combination of codeine phosphate
and paracetamol. The arm was immobilized in a sling (Medi Sling, Medi SAK, Bayreuth,
Germany) and patients started physiotherapy on the first postoperative day following
a standard rehabilitation protocol: abduction and flexion were restricted to 90° for
the first six weeks. With decreasing pain, this training was progressed with strengthening
exercises of the rotator cuff and shoulder muscles. Return to sportive activity of
the upper extremities was allowed after another 6 weeks.

Postoperative assessment

Pain was measured using the Visual Analogue Scale (VAS) on the first, second and fourteenth
postoperative day. Values between 0 and 10 could be achieved, whereas 0 stood for no pain and 10 stood for very severe pain.

Anterior chest wall numbness was assessed on the second postoperative day and six
months postoperatively. A grid (1 cm x 1 cm) was superimposed on a transparency slide
and temporary put on the patient’s clavicle and anterior chest wall (Fig. 2). The patients were instructed to palpate their chest wall for areas of numbness
or decreased sensation to light touch. This line was traced by an examiner onto the
transparency slide and measured by summarizing all 1 cm² boxes.

Fig. 2. Clinical photograph demonstrating the anterior chest wall numbness on the second postoperative
day. (a) area of numbness 3 cm² (patient 11, MOP group); (b) area of numbness 73 cm² (patient 7, COP group)

Fig. 3. Radiological outcome of a clavicle midshaft fracture OTA B2.3 (patient 11, MOP group).
(a)?+?(b) preoperative; (c)?+?(d) postoperative

Statistics

We calculated the incision-plate ratio (incision length in mm / plate length in mm)
to facilitate the comparability of the skin incision length in both groups. A small
ratio implied a small skin incision taking into account the plate length. The numbness-plate
ratio (area of numbness in mm² / plate length in mm) was calculated to facilitate the comparability of the area
of anterior chest wall numbness in both groups. A small ratio implied a small area
of numbness taking into account the plate length. Data are given in terms of the arithmetic
mean?±?standard deviation. First the data were tested on normality. Data that were
not normally distributed were tested with the Mann Whitney U test. Normally distributed
data were tested for equality of variances. Data with equal variances were tested
with the t-test und data that showed a difference in variances were evaluated with
the Welch’s unpaired t-test (two-sample unpooled t-test for unequal variances). The
t-test and the Mann Whitney U test were calculated using the software SigmaStat 3.1
(Systat Software Inc., Chicago, USA). The Welch’s t-test was performed with the software
QuickCalcs (GraphPad Software, Inc. La Jolla, California, USA). A p-value 0.05 was
considered to be significant.