The aim of this thesis was to progress our understanding of clavicle nonunion and the ability
to accurately predict fracture healing in order to improve the current management of these
injuries.
Although only one in seven fractures go onto nonunion, these are challenging to predict. It is
unclear if the recent widespread increase in the use of acute plate fixation for displaced
fractures is justified on current evidence. It is unknown whether the early accurate prediction
of fractures at high risk of nonunion is advantageous. Currently the perceived risk of nonunion
is largely based on factors available at time of injury alone. The evaluation of clinical recovery
following non-operative management and the novel use of ultrasound may advance our ability
to accurately predict fracture healing for these injuries.
The cost-effectiveness of acute clavicle plate fixation versus non-operative treatment was
estimated from randomized controlled trial data that had been previously published. This was
completed prior to the start of this thesis and the author was not involved in the original trial.
A large retrospective review of clavicle fracture fixations was undertaken to determine whether
delayed clavicle fixation has an increased risk of complications compared to acute operative
management. A prospective study of displaced midshaft fractures was carried out over a two-year period to determine the influence of functional recovery on the ability to predict fracture
healing. The influence of clavicle fracture management on the early functional recovery was
evaluated with data from a randomized controlled trial and second prospective cohort. Finally,
the novel use of ultrasound to detect early callus formation and determine whether this allows
accurate prediction of fracture healing was evaluated for a cohort of clavicle and tibia fractures.
The estimated cost per quality-of-life adjusted year of acute plate fixation over non-operative
treatment is £480,309.41/QALY. For a threshold of £20,000/QALY the benefit of acute
fixation would need to be present for 24 years to be cost-effective over conservative treatment.
Linear regression analysis identified nonunion as the only factor to negatively influence the
SF-6D at 12-months (p<0.001).
A ten-year cohort of 259 clavicle plate fixations found failed primary surgery requiring revision
fixation occurred in 7.7% of all patients. Smoking (p<0.001), presence of a post-operative
infection (<0.001), increasing age (p=0.018), and greater time delay from injury to surgery
(p=0.015) was identified as significant independent predictors on regression analysis. Receiver
operating curve analysis (ROC) revealed that surgery beyond 96 days from injury has an
increased rate of major complications and revision surgery. Using a matched case cohort of
cases before (n=67) and after the ‘safe window’ (n=77), the risk of post-operative infection
increased (Odds ratio (OR) 7.7, p=0.028), fixation failure (OR 3.8, p=0.017) and revision
surgery (OR 4.8 p=0.004). A delay to operative fixation beyond 3 months following injury
would appear to be associated with an increased risk of major operative complications and
revision surgery.
A large prospective cohort of 200 patients managed non-operatively with a displaced midshaft
clavicle fracture were recruited. Regression modelling found a QuickDASH ≥40 (p=0.001), no
callus on radiograph (p=0.004) and fracture movement on examination (p=0.001) were
significant predictors of nonunion. If none were present the predicted nonunion risk was 3%,
found in 40% of the cohort. Conversely if two or more of the predictors were present, found in
23.5% of the cohort, the predicted nonunion risk was 60%. The delayed assessment nonunion
model appeared to have superior accuracy when compared to the estimation of nonunion at
time of injury alone healing on ROC curve analysis (Area Under Curve analysis; 87.3% vs
64.8% respectively).
Data from a randomized controlled trial was used to compare 86 patients who underwent
operative fixation against 76 patients that united with non-operative treatment. The recovery
of normal shoulder function, as defined by a DASH score within the predicted 95% confidence
interval for each respective patient was similar between each group at six-weeks (operative
26.7% vs non-operative 25.0%, p=0.80), three-months (52.3% vs 44.2%, p=0.77) and six-months post-injury (86.0% vs 90.8%, p=0.35). The mean DASH score and return to work was
also comparable at each time point. Regression analysis found no specific patient, injury or
fracture predictor was associated with an early return of function following non-operative
management at six or twelve weeks.
From a pilot study of twenty clavicle fractures, six-week sonographic bridging callus appeared
to be the most accurate, and repeatable, predictor of fracture healing with a strong agreement
on intra class correlation (ICC) between four reviewers (ICC 0.82, 95% confidence interval
0.68-0.91). In a large prospective study of 112 patients, sonographic bridging callus was
detected in 62.5% (n=70/112) of the cohort at six weeks post-injury. If present, union occurred
in 98.6% of the fractures (n=69/70). If absent, nonunion developed in 40.5% of cases
(n=17/42). The sensitivity to predict union with sonographic bridging callus at six weeks was
73.4% and the specificity was 94.4%. Three-dimensional fracture reconstruction can be created
using multiple ultrasound images in order to evaluate the presence of bridging callus. This
imaging modality has the potential to enhance the usability and accuracy of identification of
fracture healing at an early stage following injury.
Nonunion following a displaced midshaft clavicle fractures accounts for the majority of poor
functional recovery and impaired quality of life over the first-year post-injury. Prediction of
clavicle fracture healing at six weeks following injury maybe a safe and effective strategy to
identify patients at greatest risk of nonunion. The use of functional recovery enables a more
accurate estimation of nonunion risk compared to conventional prediction at time of injury
alone. The use of ultrasound may further refine our ability to predict fracture healing
