Table 1 Summary of characteristics of study

Li et al. [19] RAGA

China

71–82 (77) [77 / 77]

ASA I-IV I: 39 II: 713 III: 188 IV: 2

Closed reduction and internal fixation of femur

Open reduction + internal fixation of femur

NA: SA / EA/ CSE; Type, dose, and use of nerve block were at discretion of anesthesiologist (No sedation)

GA: IV induction agents, maintained with IV or inhalational agents

*Adjunct regional blocks encouraged in both groups

* Any medications known to impair cognitive function were prohibited

Defined by: Confusion Assessment Method (CAM)

Included

Baseline assessment conducted

Postoperative D1-7

POD: Incidence, episodes, subtypes, severity of delirium; Postoperative cognitive dysfunction; Length of hospital stay; Pain control;30-day mortality; Intraoperative adverse events

Neuman et al. [18] REGAIN

United States

 > 50 [77.7 / 78.4]

ASA I-IV

I: 40

II: 499 III: 949 IV: 87

N/A

NA: Single shot SA (Sedation as needed; adjusted to ensure OAAS scale between 5 and 2) GA: Inhaled anaesthetic agent for maintenance

*Choice of agent conforming to their usual practice, all other aspects of care determined by the clinical team

Defined by: Confusion Assessment Method (CAM)

Excluded

Baseline assessment conducted Postoperative D1-3

Mortality; Recovery of walking ability;

Incidence of delirium; Length of hospital stay

Tang et al. [38]

China

 > 65 [78/ 76.6]

ASA II – IV II: 42 III: 60 IV: 8

Osteosynthesis, Artificial femoral head replacement,

Total hip replacement

NA: single shot SA; (4 ml of 0.25% hypobaric ropivacaine) (Sedation with propofol; maintained BIS 60–80) GA: combined lumbar sacral plexus block (total 40 ml 0.25% ropivacaine) + 5 μg IV sufentanil for pain relief

Induction: propofol (1–1.5 mg/kg), sufentanil (0.1–0.2 μg/kg), and cis- atracurium (0.2 mg/kg) Maintenance: propofol with effect site concentration adjusted to maintain depth of sedation (BIS: 60–80)

Defined by Confusion Assessment Method (CAM)

Excluded

Baseline assessment conducted Postoperative D1-7 or until discharged

Postoperative delirium; 30-day function status; Pain scores; In-hospital cost; Major postoperative complications

Ren and Wu [37]

China

65–79 (74.12 ± 4.15)

[73.12 ± 6.15 / 74.12 ± 4.15]

ASA I-III I: 122

II: 126

III: 33

N/A

NA: Single shot SA

(20 μg fentanyl/kg and 0.75% ropivacaine, exact dosage not specified) (sedation not specified)

GA: Induction with fentanyl 3.5ug/kg and propofol 1.5 mg/kg, Maintenance agent not specified

Not well defined and no actual data provided for this outcome

Excluded

Baseline assessment – not specified Postoperative D1-7

Postoperative delirium; cognitive impairment; Activities of Daily Living

Shin et al. [39]

Korea

71–88

[81.6/ 80]

N/A No difference in comorbidities among patient groups

Hemiarthroplasty (bipolar) / Internal fixation of femur

NA: Single shot hyperbaric bupivacaine (Dose dependent on height, Height < 160 cm: 9 mg, Height ≥ 160 cm: 11 mg) (sedation as required; midazolam starting at dose 0.02 mg/kg)

GA: TIVA group – Induction: propofol, remifentanil, cis-atracurium (exact dosage not specified) Maintenance: TCI propofol (Marsh) and TCI remifentanil (Minto), BIS 40–60 Inhaled group – Induction: pentothal sodium, cis-atracurium, remifentanil (exact dosage not specified) Maintenance: Desflurane in oxygen-air mixture (40:60) + remifentanil infusion

Defined by: aggravation or new onset delirium after surgery Assessment method N/A

Included

Baseline assessment conducted N/A

Post-inflammatory marker changes; Mortality; Morbidity

Tzimas et al. [40]

Greece

 > 65 (76)

ASA I-III (ASA I: 2 ASA II: 41 ASA III: 27)

N/A

NA: single shot SA (fentanyl 20 mcg and ropivacaine 0.75%, exact dosage not specified); (No sedation) GA: Induction: fentanyl 3–5 mg/kg and propofol 1.5 mg/kg, rocuronium 0.6 mg/kg Maintenance: Desflurane

Defined by: Confusion Assessment Method (CAM)

Excluded

Baseline assessment conducted Postoperative D1-4

Postoperative cognitive dysfunction; Incidence of delirium

Parker and Griffiths [41]

United Kingdom

52–105 (83) [82.9 / 83.0]

ASA I-II

Arthroplasty, Sliding hip screw/ plate & screws, Intramedullary nail

Exact technique and dose of drugs was the choice of the anesthetist

Defined by: 10-question mental test score

Included

Baseline assessment conducted N/A

Mortality; General complications; Postoperative delirium; Length of stay; Surgical outcome

Heidari et al. [42]

Iran

 > 30

ASA I-III

N/A

NA: SA/ EA SA: plain bupivacaine 0.5% (3 ml)

EA: plain bupivacaine 0.5% (total 25 ml) with epinephrine (1:200,000) (No sedation) GA: halothane + nitrous oxide Induction: fentanyl (2 μg/kg), thiopental (5 mg/kg); lidocaine (1.5 mg/kg); pancuronium (0.1 mg/kg) Maintenance: halothane (0.5–1.5%) in oxygen and nitrous oxide (ratio 1:1)

Defined by: new postoperative cognitive dysfunction (disorientation to time, place or person)

Excluded

Baseline assessment conducted Postoperative D1-2

Postoperative cognitive dysfunction; 30-day mortality; General surgical Complications; Pain relief;

Casati et al. [43]

Italy

67–94 (84) [ 84 / 84]

ASA II-III II: 13 III: 17

Hemiarthroplasty

NA: single shot spinal anesthetic (hyperbaric bupivacaine 7.5 mg 0.5%)

(No sedation) GA: Sevoflurane

Volatile induction (inspired concentration 5%) Maintenance anesthesia: sevoflurane

Defined by: Decline in MMSE score from baseline ≥ 2 points

Included

Baseline assessment conducted Postoperative D1-7

Postoperative cognitive dysfunction; Intraoperative hemodynamic changes and blood loss; Pain relief; PACU discharge time; Duration of hospital stay

Kamitani et al. [21]

Japan

 > 70 ( 82)[83 / 81.4]

N/A Comparable physical status between GA and SA groups

N/A

NA: single shot SA (0.5% bupivacaine, exact dosage not specified) (No sedation) GA: sevoflurane + nitrous oxide

Defined by: Confusion Assessment Method (CAM)

Excluded

Baseline assessment – not specified Postoperative D1-4

Postoperative delirium; Length of surgery; hemodynamic status; analgesic requirements