This is a unique three-fold prospective and retrospective study. With this approach, all previous and current PLIs presented at participating study sites will have the potential to be included in the study. Our goal is to collect all relevant injury and surgical parameters of the Perilunate spectrum. The investigators plan to identify each hospital within Canada that normally treats PLIs and to record injury and demographic information on each PLI that occurs in this country over a two to three-year period. Our protocol includes scheduled two, five, and 10-year follow-up intervals.

Perilunate injuries commonly occur from high-energy sporting or automobile accidents and require urgent surgical intervention. Although these wrist injuries are commonly encountered in the population, their complexity often goes unrecognized. In fact, some perilunate dislocations (PLDs) or perilunate fracture-dislocations (PLFDs) may be missed in spite of critical clinical and radiographic examination, leading to a delay in treatment. If left untreated for an extended period of time the outcomes of surgical repair are significantly compromised. The recovery process is very long, often with poor prognosis (a high incidence of post-traumatic osteoarthritis and chronic wrist pain).

Early surgical management with the restoration of normal carpal anatomy is the gold standard for surgical repair of perilunate injuries. Surgical repair may involve an open reduction of the carpal bones, repair or reconstruction of the ligaments, and internal fixation of the fractures for PLDs and PLFDs. However, there is a huge variability with respect to approach and a lot to be desired with respect to outcomes. Open surgical procedures have been reported to lead to capsular scarring and joint stiffness and further interfere with the tenuous blood supply to the scaphoid and the torn ligaments. Another treatment options, which may aid in healing with reduced stiffness, is a combination of fluoroscopy and wrist arthroscopy which allows for anatomic reduction and fixation of the carpal bones with minimal tissue dissection. Injury variability and a wide array of surgical strategies make it difficult to treat and/or make improvements on specific techniques. Given the varied nature of the injury to this joint and varied outcomes, it is important to categorize the injury characteristics, the subsequent treatment options and the long-term outcomes of different clinical interventions. Many different surgical techniques have been advocated with a variety of reduction and fixation maneuvers, but unfortunately, the literature is sparse. There are disagreements with respect to volar, dorsal or combined surgical approaches. There is no consensus on the value of prophylactic carpal tunnel release. Some surgeons advocate direct ligament repair, while others feel it is unnecessary. A third group advocates for augmentation of the scapholunate ligament with screws or a graft. While most surgeons use smooth k-wires to hold the carpal reduction, there is no agreement on direction, number, size and position of k-wires. Further, there is no agreement on how long these k-wires should be left in place or on any aspect of rehabilitation.

Globally these injuries have been poorly studied and ideal timing for surgical intervention, optimal treatment and rehabilitation are unknown. The investigators hope to establish best-evidence clinical practice guidelines for the treatment of perilunate injuries including recommendations on the timing of reduction, the timing of surgery, best-practice surgical techniques and rehabilitation protocols. The C3PO Trial will represent the single largest prospective dataset ever accrued on perilunate injuries with the support of both Canadian hand and trauma-fellowshipped trained orthopaedic surgeons and corresponding research societies. This project has the potential to create a paradigm shift in the way surgeons think about the perilunate injuries from identification through to prognosis which would be beneficial to all orthopaedic traumatologists managing these patients.

The study has 3 major nested arms. The investigators have designed a national prospective registry intended to capture all perilunate injuries suffered in Canada over a 2 year period. Within this registry, the investigators have an embedded cohort to capture all injuries that present to registered trial centres. These patients will be consented to the cohort and subsequently have extensive perioperative data recorded as well as both short and long-term follow-up (with no modification of treatment). All data collection (i.e. relevant demographics, injury characteristics, surgical and management parameters) will be obtained and managed by a customized REDCap database housed at the trial coordinating centre. The third arm of this trial is a retrospective cohort in which patients previously treated for PLIs will be contacted as asked if they would be willing come back to clinic and be follow for the remaining period of the 10-year study.

Participants, 14 years of age or older, clinically diagnosed with a perilunate injury and willing to adhere to the study protocol will be included for study participation. They must be willing and able to attend all recommended post-operative follow-up visits based on the advice of their surgeon. All participants will complete questionnaires and undergo both clinical and radiographic evaluations. These evaluations will begin at baseline, continue at the first post-operative visit, and the following intervals: 3, 6, 12, 24, 60 and 120 months. Individuals will be excluded if they have cognitive impairment or unable to understand what participation in this study entails, a known alcohol or drug abuser, or anticipated to be non-compliant. The investigators anticipate overall 150 patients entered into the cohort, an additional 150 in the registry arm, and 150 patients identified retrospectively.

Inclusion Criteria:

• The subject is 14 years of age or older
• The subject has been clinically diagnosed with a perilunate injury
• The subject is willing to adhere to the study protocol including required post-operative therapy, all scheduled follow-up visits, evaluations, and questionnaires (if applicable).

Exclusion Criteria:

There will be no limiting exclusion criteria.

Patients who sustain a perilunate spectrum injury including dislocation and/or fracture.