• Tears of the medial collateral ligament (MCL) are the most common knee ligament injury.

• Incomplete tears (grade I, II) and isolated tears (grade III) of the MCL without valgus instability can be treated without surgery, with early functional rehabilitation.

• Failure of non-surgical treatment can result in debilitating, persistent medial instability, secondary dysfunction of the anterior cruciate ligament, weakness, and osteoarthritis.

• Reconstruction or repair of the MCL is a relatively uncommon procedure, as non-surgical treatment is often successful at returning patients to their prior level of function.

• Acute repair is indicated in isolated grade III tears with severe valgus alignment, MCL entrapment over pes anserinus, or intra-articular or bony avulsion. The indication for primary repair is based on the resulting quality of the native ligament and the time since the injury. Primary repair of the MCL is usually performed within 7 to 10 days after the injury.

• Augmentation repair for the superficial MCL (sMCL) is a surgical technique that can be used when the resulting quality of the native ligament makes primary repair impossible.

• Reconstruction is indicated when MCL injuries fail to heal in neutral or varus alignment. Reconstruction might be advisable to correct chronic instability. Chronic, medial-sided knee injuries with valgus misalignment should be treated with a two-stage approach. A distal femoral osteotomy should be performed first, followed by reconstruction of the medial knee structures.

Cite this article: EFORT Open Rev 2018;3:398-407. DOI: 10.1302/2058-5241.3.170035

• The most frequent indications for arthroscopy in patients with total knee arthroplasty (TKA) are soft-tissue impingement, arthrofibrosis (knee stiffness), periprosthetic infection and removal of free bodies or cement fragments.

• When performing a knee arthroscopy in a patient with a symptomatic TKA, look for possible free/retained bone or cement fragments, which can be anywhere in the joint.

• Patellar tracking should be evaluated and soft-tissue impingement under the patella or between the femoral and tibial prosthetic components should be ruled out.

• Current data suggest that knee arthroscopy is an effective procedure for the treatment of some patients with symptomatic TKA.

• The approximate rates of therapeutic success vary according to the problem in question: 85% in soft-tissue impingement; 90% in arthrofibrosis; and 55% in periprosthetic infections.

• More clinical studies are needed to determine which patients with symptomatic TKA can be the best candidates for knee arthroscopy.

Cite this article: EFORT Open Rev 2019;4:33-43. DOI: 10.1302/2058-5241.4.180035.

• The treatment of small to moderate size defects in revision total knee arthroplasty (rTKA) has yielded good results with various techniques (cement and screws, small metal augments, impaction bone grafting and modular stems). However, the treatment of severe defects remains problematic.

• Severe defects have typically been treated with large allograft and metaphyseal sleeves. The use of structural allograft has decreased in recent years due to increased long-term failure rates and the introduction of highly porous metal augments (cones and sleeves).

• A systematic review of level IV evidence studies on the outcomes of rTKA metaphyseal sleeves found a 4% rate of septic revision, and a rate of septic loosening of the sleeves of 0.35%. Aseptic re-revision was required in 3% of the cases. The rate of aseptic loosening of the sleeves was 0.7%, and the rate of intraoperative fracture was 3.1%. The mean follow-up was 3.7 years.

• Another systematic review of tantalum cones and sleeves found a reoperation rate of 9.7% and a 0.8% rate of aseptic loosening per sleeve. For cones, the reoperation rate was 18.7%, and the rate of aseptic loosening per cone was 1.7%.

• The reported survival of metal sleeves was 99.1% at three years, 98.7% at five years and 97.8% at 10 years. The reported survival free of cone revision for aseptic loosening was 100%, and survival free of any cone revision was 98%. Survival free of any revision or reoperation was 90% and 83%, respectively.

Cite this article: EFORT Open Rev 2021;6:1073-1086. DOI: 10.1302/2058-5241.6.210007

• The main complications of surgical reconstruction of multiligament injuries of the knee joint are residual or recurrent instability, arthrofibrosis, popliteal artery injury, common peroneal nerve injury, compartment syndrome, fluid extravasation, symptomatic heterotopic ossification, wound problems and infection, deep venous thrombosis, and revision surgery.

• Careful surgical planning and execution of the primary surgical reconstruction of multiligament injuries of the knee joint can minimize the risk of the aforementioned complications.

• Careful postoperative follow-up is required to detect complications. Early recognition and prompt treatment are of paramount importance.

• To obtain good results in the revision surgery of failed multiligamentary knee reconstructions, it is crucial to perform a thorough and exhaustive evaluation to detect all the causes of failure.

• Addressing all associated injuries during revision surgery will lead to the best possible subjective and objective results, although functional outcomes are often modest.

• However, advanced age and high-energy injuries have been associated with the poorest functional outcomes after revision surgery of failed multiligament injuries of the knee joint.

Cite this article: EFORT Open Rev 2021;6:973-981. DOI: 10.1302/2058-5241.6.210057

• The use of an external fixator (EF) in the emergency department (ED) or the emergency theatre in the ED is reserved for critically ill patients in a life-saving attempt. Hence, usually only fixation/stabilization of the pelvis, tibia, femur and humerus are performed. All other external fixation methods are not indicated in an ED and thus should be performed in the operating room with a sterile environment.

• Anterior EF is used in unstable pelvic lesions due to anterior-posterior compression, and in stable pelvic fractures in haemodynamically unstable patients.

• Patients with multiple trauma should be stabilized quickly with EF.

• The C-clamp has been designed to be used in the ED to stabilize fractures of the sacrum or alterations of the sacroiliac joint in patients with circulatory instability.

• Choose a modular EF that allows for the free placement of the pins, is radiolucent and is compatible with magnetic resonance imaging (MRI).

• Planning the type of framework to be used is crucial.

• Avoid mistakes in the placement of EF.

Cite this article: EFORT Open Rev 2020;5:204-214. DOI: 10.1302/2058-5241.5.190029

• The number of rotating-hinge total knee arthroplasties (RH-TKAs) is increasing. As a result, the number of complications related to these procedures will also increase.

• RH-TKAs have the theoretical advantage of reducing bone implant stresses and early aseptic loosening. However, these implants also have complication rates that cannot be ignored. If complications occur, the options for revision of these implants are limited.

• Dislocation of RH-TKAs is rare, with an incidence between 0.7% and 4.4%. If it occurs, this complication must be accurately diagnosed and treated quickly due to the high incidence of neurovascular complications.

• If the circulatory and neurological systems are not properly assessed or if treatment is delayed, limb ischemia, soft tissue death, and the need for amputation can occur.

• Dislocation of a RH-TKA is often a difficult problem to treat. A closed reduction should not be attempted, because it is unlikely to be satisfactory. In addition, in patients with dislocation of a RH-TKA, the possibility of component failure or breakage must be considered.

• Open reduction of the dislocation should be performed urgently, and provision should be made for revision (that is, the necessary instrumentation should be available) of the RH-TKA, if it proves necessary.

• The mobile part that allows rotation can have various shapes and lengths. This variance in design could explain why the reported outcomes vary and why there is a probability of tibiofemoral dislocation.

Cite this article: EFORT Open Rev 2021;6:107-112. DOI: 10.1302/2058-5241.6.200093

• The complication rate of ankle arthroscopy (AA) ranges from 3.5% to 14%.

• To avoid such complications, it is essential to have a thorough understanding of the anatomy of the ankle, to perform the procedure very carefully and with appropriate instrumentation, and to use a non-invasive distraction technique.

• The most frequent complications are neurological (cutaneous nerve injuries), which are usually caused by direct injury during arthroscopic portals or by a distracting pin when using an invasive distraction technique. They usually resolve spontaneously within a few months.

• The iatrogenic formation of a pseudoaneurysm is a severe but extremely rare complication (an incidence of 0.008%).

• There are several treatments for pseudoaneurysms: external compression; direct thrombin injection, surgical intervention (resection of the damaged segment of the artery and reconstruction with a reversed long saphenous vein interposition graft), and endovascular embolisation.

• Other rare complications include wound infections (localised superficial infection), problems at the portal incisions (prolonged portal drainage, residual pain in the portal, portal scar dehiscence, cyst at the portal site), type I complex regional pain syndrome, instrument breakage, painful scars and nodules, and a number of other rarer complications.

• In conclusion, when performing AA, it is important to remember the potential complications and try to avoid them. When they do occur, it is essential to diagnose and treat them appropriately.