To our knowledge, this was the first cohort study to evaluate the outcome of DRF in PD patients. The most significant finding of this study was the substantially higher failure rate noted in PD (39.1% vs. 4.6%; p<0.05). In current literature, there are many studies that have indicated PD patients have inferior outcomes and have increased risks for surgical complications after orthopaedic procedures.3, 5, 10, 11. Most studies have focused on hip fractures, and the outcome for DRF remains unknown.
The outcome of fractures in patients with Parkinson’s Disease and elderly patients
Although the majority of patients that receive surgical fixation for DRF have good to excellent outcomes, PD patients appear to have inferior results. In the general population, the nonunion rate is reported to be as low as < 1% and the overall complication rate in current literature for DRF ranges from 14% to 30% in the general population.4, 12-14 In our study, we considered patients to have a treatment failure if there was loss of reduction, malunion or nonunion of fracture, or persistent pain at the injured site 6 months after surgery. We noted 4.6% of the non-PD patients had treatment failure, while 39.1% of the patients in the PD group were considered to have treatment failure. The cause for this substantially higher rate of treatment failure is currently unknown, but it is most likely multifactorial. For instance, PD patients often exhibit severe rigidity which may cause early failure of fixation.15 Hence, there was a significantly higher rate of loss of reduction in the PD group. In addition, the frail status and frequent falls exhibited in this patient population may further complicate the postoperative recovery course.6 Lastly, the frequent resting tremors observed in PD may also have altered the healing process. In order to facilitate optimal bone healing to occur, stabilizing the fracture either through relative stability or absolute stability is essential.16 Most of the current studies for fractures in PD patients have focused on hip fractures. Roche et al. evaluated 2448 patients that sustained a hip fracture, 97 of whom had PD. Their results suggested PD was not a risk for 1-year mortality. On the other hand, several reports noted an inferior outcome for PD patients after sustaining a hip fracture with mortality rates as high as 47%.6, 17 Karadsheh et al. reported PD as an independent predictor of mortality after operative treatment for femoral neck fractures. Interestingly, PD patients were more likely to sustain a dislocation after hemiarthroplasty and fixation failure for minimally displaced fractures.6 The reoperation rates for PD were 4% and 22% for displaced femoral neck fractures and nondisplaced fractures respectively. Although the two groups received different surgical interventions, the significantly higher reoperation rates in the nondisplaced group prompted the authors to favor the use of hemiarthroplasties for non-displaced femoral neck fractures in PD patients.
The choice of fixation method for DRF in PD patients
Although k-wire fixation and ESF are often considered to be relatively stable fixation techniques and provides fairly good outcomes in the general population, it should be used with caution in PD. In this study, there was a higher percentage of patients undergoing k-wire or ESF fixation in PD (n=10, 43.5% vs. n=14, 21.6%; for PD and non-PD respectively). For patients that underwent k-wire fixation, 4 (66.7%) PD patients had treatment failure while none were observed in the non-PD group (n<0.05). Meanwhile, 3 (75%) patients that received ESF had treatment failure while only 1 patient in non-PD (10%) had a treatment failure (p<0.05) (table 3). The higher rate of failure is currently unknown. However, PD patients often have frequent tremors and may cause micro-instability over the fracture site and may impede proper fracture healing. In addition, the constant rigidity exhibited in these patients may also cause excessive muscle contracture, leading to displacement of the fracture fragments. In agreement with our results, we noted the most common mode of failure were loss of reduction and nonunion of fracture in PD patients. Therefore, our authors recommend a rigid fixation method such as locked plates for PD patients in order to assure proper fracture healing.
Length of hospital stay and potential problems in caring PD patients
PD patients often have multiple comorbidities which may complicate their postoperative care. Pouwels et al. identified cancer, ischemic heart disease, and cerebrovascular disease as the three most common associated comorbidities in PD patients that have sustained a fracture.4 In this study, we noted osteoporosis to be the most commonly associated disease in a relatively small sample size, which can partly explain the higher incidence of osteoporotic fractures. In a comprehensive review of 9225 patients with hip fracture (452 patients with PD), Coomber et el. noted a significantly longer hospital stay for PD patients.3 In-hospital complications were relatively common, of which postoperative delirium, pressure sores, pneumonia all occurred more often in patients with PD. In this study, PD patients were admitted in an acute orthopedic ward for 5.3 ± 4.69 days while non-PD patients had a shorter stay of 3.78 ± 0.96 days (p=0.01). There was one PD patient complicated with aspiration pneumonia which required extended stay for treatment. Most of the postoperative complications recorded in literature can be partly attributed to the disease nature of PD as well as medication side effects (eg. sedatives). Therefore, we routinely consult neurology and geriatric specialists to manage the postoperative course.
For patients in the non-PD group, only one patient had wound dehiscence which was treated in under local anesthesia with debridement and primary closure of the wound. This patient was subsequently admitted for intravenous antibiotics. As for 30-day readmissions, there was a significantly higher rate of readmissions for PD (13% vs 1.5%, p=0.05). One patient required removal of implant, another patient received treatment for postoperative pneumonia, and another patient had a hip fracture that required surgical fixation. In addition to proper management of the DRF, detailed workup for osteoporosis and fall prevention measures is essential for PD patients to reduce postoperative complications. Since the bone mineral density in patients with PD is lower compared with healthy controls, appropriate medications such as bisphosphonates and denosumab should be initiated once osteoporosis is confirmed.18
There are several limitations in this study. This was a retrospective medical record review which may have certain bias due to the nature of the study design. In addition, there was a relatively small sample size for PD patients. In order to determine the adequate sample size, we conducted a pilot study to assure statistical significance was achieved. Furthermore, we matched our patients for age and gender in a 1 to 3 ratio with non-PD patients to overcome the relatively small sample size. Another limitation is that we did not assess the clinical function and PD disease status of our patients which could provide a better overall evaluation. Finally, Future studies should also include a group of PD patients that received nonoperative management after DRF to better assess the necessity of surgical fixation in this unique group.