Intraoperative Nerve Block

Nerve blocks offer the advantage of extended pain relief after complex knee surgeries with decreased narcotic requirements in the early postoperative period. Multiple nerve blocks have been described, most commonly sciatic and femoral. The proximal location of femoral and sciatic nerve blocks results in both sensory and motor deficits. Although early measurable decreases in quadriceps strength have been described with these blocks, they do not appear to have long-term implications on functional testing or return to sport. ^, Combined femoral and sciatic nerve blocks have been demonstrated to result in lower perioperative opioid requirements compared with femoral nerve block alone, but there are no differences in opioid consumption, pain scores or patient satisfaction over the first 3 postoperative days. Adductor canal blocks are performed more distal than femoral nerve blocks, approximately 12 to 14 cm proximal to the knee. The adductor canal is bounded by the vastus medialis, sartorius and adductor magnus, and within it run the femoral artery and vein, sensory branch of the obturator nerve, saphenous nerve and motor nerve to the vastus medialis. Although some weakness of the vastus medialis is possible, this block affects fewer motor branches of the femoral nerve, therefore offering the benefit of similar pain relief to femoral nerve blocks without significant motor deficits.

Nerve blocks can be performed as a single shot or as an indwelling nerve catheter. A study comparing these two in a population of patients treated with total knee arthroplasty found no difference in the cumulative opioid requirements and functional outcomes after 48 hours, despite lower visual analogue scale (VAS) pain scores in the early postoperative period.

Intraarticular catheters have fallen out of favour because of the chondrotoxic effects of anaesthetics. Buchko et al. described a 28% incidence of chondrolysis associated with intraarticular pain pumps with bupivacaine and adrenaline (epinephrine).

Periarticular Injections

Periarticular injections at the time of wound closure have been demonstrated to provide excellent pain control after knee ligament reconstruction. These can be performed with liposomal bupivacaine, ropivacaine or multimodal drug cocktails. As opposed to nerve blocks, which have the potential to cause unwanted motor deficits or iatrogenic nerve injury, periarticular injections have not been reported to have these potential complications. In a randomised controlled, double-blinded study, 56 adults undergoing anterior cruciate ligament (ACL) reconstruction with a femoral nerve block and local bupivacaine had no difference in VAS pain scores, narcotic consumption or patient satisfaction in the first 3 postoperative days compared with local periarticular bupivacaine alone. Based on results such as this, there may not be enough of a significant clinical benefit of a femoral nerve block over a periarticular injection to justify its routine use.

In a randomised controlled study comparing intra- and periarticular injections after ACL reconstruction, Koh et al. found that a periarticular multidrug cocktail of ropivacaine, ketorolac, adrenaline (epinephrine) and cefuroxime resulted in lower VAS pain scores on postoperative day 1 than patients who received an intraarticular multidrug cocktail. These authors postulated that the periarticular injection more efficiently blocks peripheral pain sources by reducing peripheral sensitisation caused by surgical trauma.

If a periarticular injection is to be performed in combination with a nerve block, the cumulative dose of local anaesthetic must be calculated to ensure the maximal dose for each particular patient is not exceeded.

Oral Medications

In the outpatient setting, oral pain medications are the gold standard for postoperative pain management after orthopaedic procedures. There are endless options for pain control, ranging from immediate release opioids, extended release opioids, over-the-counter analgesics, benzodiazepines, anxiolytics and sedatives.

Opioids remain the cornerstone in managing acute postoperative pain, despite their abuse potential and side effects of nausea, vomiting, drowsiness and constipation. Paracetamol (acetaminophen)–containing opioids must be dosed with caution to avoid paracetamol toxicity. Non–paracetamol-containing opioids, such as oxycodone, can be considered in patients who might otherwise exceed recommended doses of paracetamol with routine use. The maximum daily adult dose of paracetamol is 4000 mg. For children younger than 12 years and/or less than 50 kg, the maximum daily dose is 75 mg/kg. Responsible prescribing of opioid medications requires patient and family education regarding side effects, abuse potential and expectations regarding dosing and duration of use of opioid medications.

One alternative strategy to narcotic medications is to prevent the pain before it starts by desensitising the central nervous system. Drugs such as gabapentin and pregabalin act by this mechanism. Results from patients treated with gabapentin at the time of ACL reconstruction have been mixed. ^, One randomised controlled trial demonstrated lower VAS pain scores and fewer opioids in patients treated with a single preoperative dose of 600 mg gabapentin compared with placebo, whereas another found no difference in pain scores or opioid consumption in the first 3 postoperative days when comparing a single preoperative dose of gabapentin versus controls. Gabapentin, when used, is often used in the perioperative period or as one component of a postoperative multimodal pain management strategy.

Sleep deprivation has been associated with increased sensitivity to pain, and therefore administration of a sleep aid has been used as part of a multimodal strategy to improve pain control. Tompkins et al. found a 28% reduction in opioid consumption in 29 patients treated with zolpidem once daily for 7 days after ACL reconstruction compared with placebo, with no difference in overall fatigue.

Cryotherapy

Nonpharmacological approaches to pain management are designed to reduce the use of prescription pain medications. In the setting of the current opioid epidemic, the use of effective nonpharmacological strategies for postoperative pain should be a priority. Cryotherapy reduces intraarticular temperatures, which interferes with the conduction of nerve signals and reduces local blood flow, leading to decreased swelling and perceived pain. Cryotherapy can be administered in numerous forms, including combined compression and cryotherapy systems such as Game Ready (CoolSystems, Inc, Concord, CA, USA), NICE (Nice Recovery Systems, Boulder, CO, USA) and numerous other brands; commercial cold wraps such as Cryo-Cuff (DJO Global, Dallas, TX, USA); and simple ice packs. Duration of treatment varies based on the system used. Most importantly, patients and their families should be educated on the importance of having a barrier, such as a towel or pillowcase, between the skin and ice to avoid frostbite. Multiple level I studies have demonstrated lower VAS pain scores and prescription narcotic use among patients treated with cryotherapy compared with controls. ^,

Incidence of Deep Vein Thrombosis and Pulmonary Embolism

VTE, including DVT and pulmonary embolism (PE), is a common complication after major surgical procedures, and patients having orthopaedic surgery are commonly cited as one of the highest risk groups. Risk factors specific to orthopaedic patients include the use of a tourniquet, immobilisation, extremity surgery causing endothelial vascular injuries and a history of trauma. The incidence of DVT after major orthopaedic surgery ranges from 40% to 60%. Although VTE, when detected, is easily treatable, rates of death within 1 month of diagnosis are alarmingly high. Approximately 6% of patients with DVT and 12% of patients with PE have been reported to die within 1 month of diagnosis. Although the highest risk patients are those with lower extremity fractures, hip or knee arthroplasty, and spinal cord injury, arthroscopic knee surgery is deemed a moderate risk factor VTE.

Multiple studies describe the risks of VTE after knee arthroscopy and ligament reconstruction procedures, which range from 0% to 18%. The largest of these studies used the US Department of Defense medical data repository and identified 87 symptomatic VTE events after 16,558 ACL reconstructions, a rate of 0.53%. The odds of a VTE increased with age older than 35 years, nicotine use, concomitant high tibial osteotomy or posterior cruciate ligament reconstruction and postoperative use of nonsteroidal antiinflammatory drugs (NSAIDs). Although the rate of symptomatic VTE is less than 1%, the risk of asymptomatic VTE is high in some studies. A systematic review of six studies with 692 patients with a mean age of 31 years treated with ACL reconstruction and no postoperative pharmacological anticoagulation identified 58 patients (8.5%) with a DVT diagnosed by screening ultrasound. Of those, only 27% were symptomatic.

Two studies have assessed the risk of thromboembolism after multiligament knee reconstruction. Engebretsen et al. described a 3.5% incidence of DVT after multiligamentous knee reconstruction in 85 patients who did not receive thromboprophylaxis. Among a cohort of 136 patients with a mean age of 32 years (range 15 to 61 years), Born et al. identified 3 patients who developed a postoperative symptomatic DVT within 3 months of their reconstruction. All occurred on the operative extremity at a mean time of 39 days after surgery and involved the popliteal, posterior tibial and peroneal veins. All three patients were on low molecular weight heparin after surgery. No risk factors for DVT could be identified secondary to the small number of affected patients.

Mechanical Prophylaxis

Mechanical methods of VTE prophylaxis include mobilisation, graduated compression stockings, pneumatic compression devices and foot pumps. The benefits of these therapies, compared with pharmacological prophylaxis, include the lack of bleeding events and no need for laboratory monitoring. Mechanical prophylaxis can also be used in combination with pharmacological prophylaxis. Although a simple strategy, implementation of mechanical prophylaxis may be difficult in patients who have recently undergone a significant lower extremity reconstructive surgery. Perhaps the simplest of these methods is mobilisation. Although weightbearing restrictions and early postoperative elevation may limit early mobility, we recommend that patients be encouraged to mobilise for simple tasks such as using the restroom, eating meals and sitting upright in a chair rather than prolonged periods of lying flat. Early mobilisation has been most studied in the arthroplasty literature, with multiple studies describing dramatically decreased rates of DVT associated with mobilisation in the first 24 hours.

Pharmacological Prophylaxis

Pharmacological prophylaxis includes aspirin, unfractionated or low molecular weight heparin (LMWH), factor Xa inhibitors and vitamin K antagonists. The use of aspirin as a sole strategy for VTE prophylaxis is largely unsupported by the AAOS, although their formal guidelines for VTE prophylaxis are specific to patients undergoing elective hip and knee arthroplasty. There are no formal evidence-based guidelines for VTE prophylaxis in nonarthroplasty knee reconstruction. Therefore we recommend that surgeons consider each patient’s age, risk profile and surgical procedure to determine whether he or she may be appropriate for a combination of mobilisation and aspirin as VTE prophylaxis.

Vitamin K antagonists, such as warfarin, are effective anticoagulants that require monitoring of the prothrombin time (PT) and international normalised ratio (INR). Warfarin requires a minimum of 48 hours to reach therapeutic levels, so if immediate anticoagulation is necessary, warfarin must be bridged with LMWH until the INR reaches therapeutic levels. The American College of Chest Physicians (ACCP) and CHEST guidelines recommend warfarin in patients undergoing hip or knee arthroplasty and hip fracture surgery, but there are no specific recommendations for their use in nonarthroplasty knee reconstruction.

LMWH is considered the gold standard for VTE prophylaxis in orthopaedic patients, largely in part to its efficacy, better risk profile compared with heparin and warfarin and lack of need for monitoring of blood levels. However, its effects, with respect to VTE and bleeding events in patients after knee arthroscopy and ACL reconstruction, are mixed. Michot et al. performed a randomised trial of LMWH versus no prophylaxis among 218 patients after knee arthroscopy, including ligament reconstruction, and identified asymptomatic DVT in 15% of controls and 1.5% of patients treated with LMWH on screening ultrasound. LMWH was associated with minor bleeding in 12% of patients compared with 6% of controls. Similar results were described by Wirth et al. among 262 patients undergoing knee arthroscopy, with symptomatic DVT occurring in 4% of controls and 0.8% of those treated with LMWH. The relatively small number of patients in these studies, combined with the low rates of DVT and PE, limit the authors’ conclusions.

A 2019 meta-analysis of randomised controlled trials evaluated the benefits of LMWH with respect to simple knee arthroscopy and ACL reconstruction. In a cohort of 4113 patients, LMWH, compared with non-LMWH, had no significant efficacy in preventing VTE in patients undergoing simple knee arthroscopy but increased the risk of bleeding events in this population. In contrast, LMWH had significant efficacy in preventing VTE in patients undergoing ACL reconstruction and did not increase the risk of bleeding events.

There are multiple new oral anticoagulants on the market, including factor Xa inhibitors (rivaroxaban and apixaban) and thrombin inhibitors (dabigatran). These have been recommended for VTE prophylaxis after hip and knee arthroplasty, but are not described in detail in this chapter because there are not currently indications for their use in nonarthroplasty knee reconstruction.

Ultimately the benefits of prophylaxis for each individual patient must be weighed against the medication-associated side effects to determine the appropriate recommendation for VTE prophylaxis. ACCP guidelines recommend that no VTE prophylaxis be provided to patients undergoing knee arthroscopy without a history of VTE. The National Institute for Health and Care Excellence recommends LMWH for 2 weeks for patients undergoing arthroscopic knee surgery with anaesthesia time greater than 90 minutes or if the patient’s VTE risk outweighs the risk of bleeding. Although specific recommendations do not exist for nonarthroplasty knee reconstructions, given the extensive nature of the dissections, longer surgical times and prolonged altered weightbearing status, we recommend in general that surgeons err towards arthroplasty-type DVT prophylaxis regimens, more so than published recommendations, for simple knee arthroscopy. However, more aggressive DVT prophylaxis regimens must be carefully considered in the setting of high-energy injuries in which the sequelae of bleeding complications may result in significant morbidity.

Fever

Classic postoperative causes for fever include atelectasis, wound infection, DVT or PE and urinary tract infection (in the setting of an intraoperative or postoperative Foley catheter). An occasional temperature of less than 38.6 °C (101.5 °F) in the first several postoperative days is not unusual, and patients can be reassured that this is normal. Mobilisation and the use of an incentive spirometer should be encouraged and recommended for patients with a low-grade temperature. Consistent temperatures of 38.6 °C (101.5 °F) or greater, however, are a clear indication for the patient to be evaluated in person.

Infection

The risk of infection after knee arthroscopy and reconstructive procedures is low. Multiple large database studies report an incidence of infection after knee arthroscopy of 0.25% to 0.41%. ^, More significant procedures with longer operative times may have slightly higher, albeit low, rates of infection. Patients and their families should be instructed regarding concerning signs or symptoms, including fever greater than 38.6 °C (101.5 °F), wound drainage and erythema. Although we recommend that the risk of infection be discussed in the informed consent process, patients should be reassured that this is rare and unlikely in routine arthroscopy cases. Fortunately, in the majority of knee reconstruction cases prompt treatment of the infection with surgical irrigation and debridement and antibiotics can result in successful treatment with the ability to maintain the ligament graft.

Frostbite

Frostbite, as a result of ice applied directly to the skin or with too thin a barrier, can cause patches of erythema in the area of ice application. To the patient, family member or nonorthopaedic physician, these can be concerning for potential infection. These erythematous patches may be slightly raised, generally do not occur directly overlying the incision, are less confluent than erythema secondary to infection and do not cause wound drainage. In addition, cryotherapy systems that are applied with too tight of straps may cause a constrictive force on the knee and increased pain as the sleeve expands with water inflow.

If patients have a concern regarding infection or any postoperative wound complication, they should be encouraged to contact their surgeon rather than their primary care physician or urgent care/emergency department to ensure proper management.

Arthrofibrosis

Arthrofibrosis, in the setting of complex knee reconstruction surgery, can be a potentially devastating complication with significant impacts on patient function and outcomes. Rates of arthrofibrosis after ACL reconstruction have been described to be approximately 5%, with higher rates of 9% to 13% ^, after multiligament knee reconstruction. Multiple risk factors for arthrofibrosis have been described, including age younger than 18 years, concomitant meniscal or chondral procedures, female sex, surgery within 28 days of injury and quadriceps tendon and patellar tendon grafts. Historically, ligament repair, unnecessarily staged procedures, nonanatomical reconstructions and improper rehabilitation protocols required prolonged immobilisation and weightbearing restrictions that likely contributed to the development of arthrofibrosis and graft failure. However, trends towards biomechanically superior anatomical reconstruction allow the safe initiation of early motion to restore stability and reduce the risk of arthrofibrosis. ^{, ,} For this reason, the authors recommend anatomical reconstructions with early range of motion as allowed based on the patient’s specific surgical procedure. Postoperative protocols, with respect to weightbearing status and range of motion, should be clear and expectations discussed with the patient and physical therapist to ensure anticipated outcomes are achieved.