Proximal tibiofibular joint (PTFJ) dislocation due to Ehlers-Danlos syndrome: posterolateral open-wedge high tibial osteotomy combined with medial closed-wedge distal femoral osteotomy can correct the severe valgus deformity with a markedly increased tibial posterior slope.

Ehlers-Danlos syndrome (EDS) causes joint hypermobility and joint dislocation. Since there are no reports of proximal tibiofibular joint (PTFJ) dislocation caused by EDS, little is known about the long-term course of this disease. A woman in her 40s presented with a posterolaterally depressed tibial condyle and severe valgus deformity caused by a long-standing PTFJ dislocation due to EDS. Considering the pathology, posterolateral open-wedge high tibial osteotomy (PLOWHTO) and medial closed-wedge distal femoral osteotomy were performed according to the deformity analysis. A favourable short-term clinical outcome was obtained and the PTFJ dislocation was reduced over time. Although PLOWHTO has several pitfalls, it is a logical and useful surgical technique that can help treat posterolateral dysplasia of the tibial plateau concomitant with severe valgus deformity, regardless of joint laxity, if performed with attention to pitfalls.

[Traumatic dislocation of the knee].

Traumatic dislocation of the knee is a rare orthopaedic injury with often severe concomitant damage. In addition to the ligamentous injuries there is a significant risk of vascular injury, which can be potentially limb-threatening if undiagnosed or late recognized. It is therefore crucial with a correct and safe diagnostic method in the acute phase. Dislocation is caused by both high- and low-velocity mechanisms. Obesity is a single risk factor of low-velocity knee dislocation. Other than nerve and vascular damage, dislocation is associated with numerous intra- and extraarticular injuries, as argued in this review.

Review of Extensor Mechanism Injuries in the Dislocated Knee.

Knee dislocations, aka multiligamentous injuries, are uncommon but devastating injuries often following high-energy trauma. Tears of the major knee stabilizers are well documented; however, injuries of the knee extensor mechanism are less commonly reported. The extensor mechanism is comprised of the patella, patellar tendon, and quadriceps tendons. Magnetic resonance imaging (MRI) is the preferred imaging modality of internal derangements of the knee due to its excellent soft tissue contrast. In this article, we will discuss the normal imaging findings of the extensor mechanism and review abnormalities following knee dislocation.

Knee Dislocation With Acute Anterior Cruciate Ligament Reconstruction and Posterior Cruciate Ligament and Medial Collateral Ligament Repair.

SUMMARY: This video depicts the materials and steps for the repair of a Schenck classification KD III multiligamentous injury in a patient who had bilateral injuries after his car pinned him to a cabinet in his garage. The video demonstrates acute allograft reconstruction of anterior cruciate ligament and primary repair of the avulsions of posterior cruciate ligament and medial collateral ligament in the patient.

Systematic review and meta-analysis of bearing dislocation in lateral meniscal bearing unicompartmental knee replacement: Domed versus flat tibial surface.

BACKGROUND: Bearing dislocation is a problem following mobile bearing Oxford lateral Unicompartmental Knee Replacement (UKR). Therefore, the design of the tibial component was changed from a flat tibial surface to a domed tibial surface with a biconcave bearing to increase bearing entrapment. This systematic review compared the dislocation and revision rates of the two designs. METHODS: Two authors independently searched MEDLINE, EMBASE and ISI Web of Science, reference lists of retrieved articles, and the internet. Randomised, cohort, case-control and case studies of adult patients with lateral knee osteoarthritis treated with flat or domed Oxford lateral UKR and their outcomes were included. The overall dislocation rate and the annual revision rate (per 100 component years) were determined. RESULTS: Nine studies (937 knees) met the inclusion criteria (3 flat, 6 domed). Four studies (all domed) had a low risk of bias and five had a high risk (3 flat, 2 domed), so data should be interpreted with caution. The bearing dislocation rate decreased from 17% (flat) to 3.7% (domed). Dislocations occurred on average at 16 months and medial dislocations were most common. The revision rate excluding dislocation decreased from 1.1%pa to 0.7%pa. PROSPERO registration: CRD42019139250. CONCLUSION: Modifying the tibial component from a flat to a domed shape decreased the bearing dislocation rate to 3.7% and increased the 10 year survival rate excluding dislocation to 93%. The dislocation rate is still relatively high so bearing stability should be assessed intra-operatively and if unacceptable, a fixed bearing version of the Oxford lateral tibial component can be inserted.

Bearing dislocation of mobile bearing unicompartmental knee arthroplasty in East Asian countries: a systematic review with meta-analysis.

BACKGROUND: Bearing dislocation is a common postoperative complication of mobile-bearing unicompartmental knee arthroplasty, and East Asian patients tend to be at higher risk. However, whether this high dislocation rate is common in all East Asian populations remains unclear. This meta-analysis was performed to explore this issue and describe various features of dislocation in East Asians, including the onset time, dislocation direction, and re-dislocation rate. METHODS: The literature was searched in PubMed, Embase, Ovid, and Cochrane Library up to May 2020. Studies were scrutinized by two independent authors, and the bearing dislocation rate, onset time, direction, and re-dislocation rate were specifically analyzed. RevMan 5.3 was used for the statistical analysis. RESULTS: Seven case series from Korea, China, and Japan were included. The pooled analysis showed that the total dislocation rate was 2.37%, while the subgroup analysis showed that the dislocation rate in Korea and other countries was 4.50% and 0.74%, respectively (P < 0.01). Another subgroup analysis of the onset time showed a significant difference before and after the first 5 years postoperatively (P < 0.01). Anterior and posterior dislocations were more frequent than medial and lateral dislocations (P < 0.01). The average re-dislocation rate was 32.45%, which was approximately seven times higher than the primary dislocation rate (P < 0.01). CONCLUSION: Our meta-analysis demonstrated that Korea had a higher bearing dislocation rate among East Asian countries, especially in the first 5 years after primary UKA. Anterior and posterior dislocations were common. The most important finding is that the re-dislocation rate can be much higher than the initial dislocation rate.

Distal biceps femoris avulsions: Associated injuries and neurological sequelae.

BACKGROUND: The aim of this study was to describe associated injuries in cases of distal biceps femoris avulsions (DBFA) as well as the incidence of neurological injury and radiographic abnormalities of the common peroneal nerve (CPN). METHODS: A retrospective chart review was conducted of patients presenting to our office or trauma center with DBFA injuries. Demographic data was obtained as well as mechanism of injury. Assessment of concomitant injuries and presence of neurologic injury was completed via chart review and magnetic resonance imaging (MRI) review. The CPN was evaluated for signs of displacement or neuritis. RESULTS: Sixteen patients were identified (mean age-at-injury 28.6 years, 87.5% male) with DBFA. Three patients (18.8%) sustained their injuries secondary to high energy trauma while 13 (81.3%) had injuries secondary to lower energy trauma. Nine patients (56.3%) initially presented with CPN palsy. All patients presenting with CPN palsy of any kind were found to have a displaced CPN on MRI and no patient with a normal nerve course had a CPN palsy. CONCLUSIONS: This case series demonstrates a strong association between DBFA and CPN palsy as well as multi-ligamentous knee injury (MLKI). These injuries have a higher rate of CPN palsy than that typically reported for MLKI. Furthermore, these findings suggest that CPN displacement on MRI may be a clinically significant indicator of nerve injury. LOE: IV.

Initial Evaluation and Classification of Knee Dislocations.

The traumatic knee dislocation (KD) is a complex condition resulting in injury to >1 ligament or ligament complexes about the knee, termed multiligament knee injuries. Typically, KDs result in injury to both cruciate ligaments with variable injury to collateral ligament complexes. Very rarely, KD may occur with single cruciate injuries combined with collateral involvement but it is important to understand that not all multiligament knee injuries are KDs. Patients can present in a wide spectrum of severity; from frank dislocation of the tibiofemoral joint to a spontaneously reduced KD, either with or without neurovascular injury. The initial evaluation of these injuries should include a thorough patient history and physical examination, with particularly close attention to vascular status which has the most immediate treatment implications. Multiple classification systems have been developed for KDs, with the anatomic classification having the most practical application.

Combined ACL-PCL-Medial and Lateral Side Injuries (Global Laxity).

The multiple ligament injured knee is a complex problem in orthopedic surgery. These injuries may or may not present as acute knee dislocations, and careful assessment of the extremity vascular and neurological status is essential because of the possibility of arterial and/or venous compromise, and nerve injury. These complex injuries require a systematic approach to evaluation and treatment. Physical examination and imaging studies enable the surgeon to make a correct diagnosis and formulate a treatment plan. Knee stability is improved postoperatively when evaluated with knee ligament rating scales, arthrometer testing, and stress radiographic analysis. Surgical timing depends upon the injured ligaments, vascular status of the extremity, reduction stability, and the overall health of the patient. The use of allograft tissue is preferred because of the strength of these large grafts, and the absence of donor site morbidity.

Knee Dislocations in the Morbidly Obese Patient.

Ultra-low-velocity knee dislocations are historically rare but increasingly common events. They occur most frequently in obese, morbidly obese, and super obese patients during everyday activities, but they can be as severe or more severe than high-velocity knee dislocations. Ultra-low-velocity knee dislocations frequently are associated with neurovascular injury and other complications. Diagnosis, early reduction, and identification and treatment of vascular injuries are critical to reducing the risk of limb ischemia and possibly amputation. Given the size of the limb, maintenance of reduction in these patients almost always requires external fixation. Although surgery on morbidly obese patients may be technically challenging, surgical reconstruction leads to improved subjective and objective results and is recommended.

Dislocation of modern design rotating hinge total knee arthroplasty : case series and narrative review.

Knee dislocation is an infrequent complication after rotating hinge total knee arthroplasty (RHTKA). The aim of the present study was to describe our experience with dislocating RHTKA in a consecutive prospective large series, its occurrence rate, causative mechanisms and to perform a review of available literature. In total, six dislocations were observed in 303 RHTKA procedures (NexGen RHK, ZimmerBiomet, Warsaw, Indiana, US) at a mean of 10 (range, 2 - 24) months after surgery. This results in a 2% dislocation rate, which is lower than the 3.1% cumulative rate reported earlier in literature. Men and women were distributed equally, with a mean age of 56 years old. The indication for RHTKA among the six dislocations was revision in 4 cases and primary arthroplasty for the other 2 cases. Analysis revealed that the main mechanism of hinge dislocation was forced knee flexion with concomitant extensor mechanism insufficiency (4/6 cases). The second cause was unscrewing of the locking pin (2/6 cases). This is probably caused by the screw home mechanism that results in a counterclockwise torque -and therefore a loosening- effect on locking bolts, specifically in right-sided RHTKA. Obesity probably predisposes to hinge dislocation since 83% of patients in this series were obese (BMI, range 34 to 52). The findings of this study suggest that dislocation of RHTKA is a rare complication that could happen to obsese patients without an adequate extensor mechanism. Level of evidence : IV.

The Irreducible Knee Dislocation.

Irreducible knee dislocations are a small subset of acute knee dislocations and are extremely rare. The most common type of irreducible knee dislocation is posterolateral, which can be challenging to diagnose both clinically and on plain radiographs. Vascular injury is uncommon and closed reduction is seldom possible due to medial femoral condyle buttonholing through soft tissues requiring open or arthroscopic reduction. Ligament injuries mostly include medial collateral ligament, anterior cruciate ligament, and posterior cruciate ligament. Literature has numerous case reports with a couple of small series giving short- to mid-term outcomes of posterolateral knee dislocations. There is, however, no consensus on management of ligament injuries with case reports showing good outcomes in early or delayed ligament reconstruction. This article sheds light on previous case reports and describes how to identify irreducible knee dislocations and provides an algorithm on how to manage ligament injuries in posterolateral dislocations.

Long-term clinical and radiological outcomes after multiligament knee injury using a delayed ligament reconstruction approach: A single-center experience.

PURPOSE: To present long-term clinical and radiological results of patients treated with delayed reconstruction of multiligament knee injuries. METHODS: Clinical data from 26 patients (21 men, five women, mean age 27.44 years) were retrospectively reviewed. Patients were evaluated at final follow-up with the use of: The International Knee Documentation Committee score (IKDC), Knee injury and Osteoarthritis Outcome Score (KOOS), Tegner Activity level, Lysholm Knee Scoring Scale, EuroQol subjective knee evaluation form, and KT-2000 arthrometer. Mean follow-up time was 105.38 months. Both knees were radiographically evaluated for osteoarthritis according to the Kellgren-Lawrence classification. RESULTS: No patient required mobilization under anesthesia for adhesion lysis at the immediate or later postoperative duration. There was no statistically significant difference in range of motion between the healthy and operated sides (P = 0.713). Mean time to final range of motion regain was 2.1 ±â€¯0.4 months. Average KT-2000 side-to-side (operated vs. normal) difference was 2.03 ±â€¯1.1 mm, and the difference was statistically significant (P = 0.007). The mean IKDC, KOOS, Lysholm, Tegner, and Euroqol-5D postoperative scores were 82.13 ±â€¯17.5, 84.59 ±â€¯16.8, 90.6 ±â€¯6.4, 4.3 ±â€¯1.3, and 80 ±â€¯11.74, respectively. Multiple regression analysis showed that age and follow-up time had significant effects on each clinical score, except for the Lysholm and Tegner scores. Progression of osteoarthritic changes of the reconstructed knee and its contralateral side was significantly different (P = 0.003). CONCLUSION: Excellent clinical results were reported from this center's long-term experience with delayed ligament reconstruction, and osteoarthritic changes of reconstructed knees were recorded.

Importance of Early Diagnosis and Care in Knee Dislocations Associated with Vascular Injuries.

BACKGROUND: Arterial injury secondary to acute knee dislocation (KD) is a rare but devastative complication. The aim of this study is to evaluate functional sequelae and factors of poor prognosis. METHODS: A retrospective monocentric series of consecutive KD with acute ischemia by popliteal artery injury was analyzed between 2005 and 2017. The main outcome was the amputation rate. RESULTS: Sixteen dislocations were included. Nine (56%) were due to public road accidents, 5 (31%) were due to falls from height, and 2 (13%) were due to sports injuries. Dislocation had occurred in the posterior location in 8 (50%) cases. Regarding arterial injury, there were 7 (44%) ruptures, 7 (44%) dissections, and 2 (13%) isolated thromboses. Eleven (69%) KDs with vascular trauma were associated with signs of acute ischemia. Revascularization was achieved by anatomical venous bypass in 14 (88%), resection and direct anastomosis in one (6%), and isolated thrombectomy in one (6%). Median time to surgery (time between trauma and vascular repair) was 7 hours (3.25-60.92 hours). Primary revascularization was performed in 12 (75%) cases. In three cases (19%), orthopedic reduction and stabilization were performed first. In one case, (6%) three-step management with vascular shunt at first, then with knee stabilization, and finally vascular bypass was carried out. Stabilization was achieved by using an external fixator in 13 (82%) cases, by open reduction and internal fixation in one case (6%), by ligamentoplasty in one (6%), and by using a long leg cast in one (6%). Fasciotomy was required in 12 (75%) cases. Two patients had early vascular complications, and 2 had early systemic complications. Three secondary transfemoral amputations were performed. Median follow-up duration was 23 months. No secondary amputation was recorded. At the end of follow-up, functional outcomes were evaluated using the Oxford Knee Score (OKS). The median OKS was 30 versus the pretrauma median OKS of 47 (P < 0.00028). No risk factor associated with limb amputation has been highlighted. CONCLUSIONS: Analysis of these results provided indications for therapeutic management of this condition. This study shows poor functional outcomes because of severity of vascular lesion in patients with orthopedic trauma but with healthy arteries.

Tibiofemoral dislocation after primary total knee arthroplasty: a systematic review.

INTRODUCTION: Tibiofemoral dislocation is the most serious form of instability following total knee arthroplasty (TKA). It is little reported in the literature, despite severity comparable to that in the native knee. The present systematic review and meta-analysis aimed to identify risk factors and treatment strategies. METHODS: The Cochrane, Medline (via PubMed), Google, and PROSPERO data-bases were searched in January 2018 following the PRISMA meta-analysis guidelines. All articles referring to tibiofemoral dislocation following primary TKA were included for analysis and extraction of individual data. Study data comprised age, gender, comorbidities, primary and revision implant design, aetiology, and treatment strategy. RESULTS: Individual data for 57 patients (23 studies) were analyzed. A total of 62.0% of primary implants were posterior-stabilized (49 patients) and 30.4% posterior-cruciate-retaining (24 patients). Obesity was the most frequent comorbidity (39.2%; 31 patients), followed by severe pre-operative deformity (31.6%; 25 patients). Aetiologies of dislocation were mainly related to comorbidity (15 studies; 65.2%) or intra-operative iatrogenic destabilization (14 studies; 60.9%). Non-operative treatment (splint) after dislocation was associated with high rates of recurrence (39.1%) but significantly fewer complications (p = 0.033). Implant revision surgery (45 patients; 80.4%) usually involved higher-constraint models (31 patients; 70.8%). CONCLUSIONS: Improved implant design has reduced the rate of tibiofemoral dislocation, although this complication remains serious in both the short and the long term. The present review identified patient- and surgeon-related risk factors. Awareness of the former, which are identifiable pre-operatively, and of the most frequent technical errors is critical.

Posterior dislocation following revision total knee replacement arthroplasty: a case report and literature analysis.

Knee dislocation following total knee replacement arthroplasty is a rare but serious complication. The incidence of dislocation following primary total knee arthroplasty with posterior stabilized implants ranges from 0.15 to 0.5%, and posterior dislocation after revision total knee arthroplasty is even rarer. Here, we report the case of a 76-year-old male who presented with posterior dislocation after posterior stabilized revision total knee arthroplasty.

Traumatic Knee Dislocation and Popliteal Artery Injury: A Case Series.

Popliteal artery injury is a potentially limb-threatening complication of traumatic knee dislocation. We describe 2 such cases that had been treated in our unit over the last decade. The first one was a 23-year-old woman who injured her right knee during a long jump competition, and the second was a 27-year-old man who had a motorbike accident. Both suffered traumatic knee dislocation along with significant ligament and neurovascular injuries. In the first patient, the popliteal artery was found thrombosed due to intimal rupture and required thrombectomy and vein patch repair, whereas in the second patient, the artery was completely transected and required end-to-end anastomosis. Both limbs were successfully revascularized and required subsequent orthopedic procedures to stabilize the knee joint. Traumatic knee dislocations are rare injuries that may be associated with potentially devastating vascular complications. A prompt diagnosis and timely arterial repair is of paramount importance if limb salvage is to be achieved.

Anterolateral Ligament Injury in Knee Dislocations.

PURPOSE: The purpose of this study is to describe the prevalence and associated factors of anterolateral ligament (ALL) injury in knee dislocation (KD). METHODS: A retrospective review of charts and radiological images was done for patients who underwent multiligamentous knee reconstruction surgery for KD in the authors' institution from May 2008 to December 2016. The inclusion criteria were both genders, skeletally mature, and first dislocation. Previous anterior cruciate ligament injury or surgery were the exclusion criteria. Magnetic resonance imaging was used to describe the ALL injury. The association of ALL injury with other variables related to the injury and the patient's background features was examined. RESULTS: Forty-eight patients (49 knees) were included. The mean age of the patients was 32.3 ± 10.6 years. High-energy trauma was the mechanism of dislocation in 28 (57.1%) knees. Thirty-one knees (63.3%) were classified as KD type IV. Forty-five (91.8%) knees had a complete ALL injury, and 3 (6.1%) knees had incomplete ALL injury. Forty (81.6%) knees had a complete ALL injury at the proximal fibers of the ALL, while 23 (46.9%) knees had complete distal ALL injury. None of the 46 (93.9%) knees with lateral collateral ligament injury had normal proximal ALL fibers (P = .012). Injury to the distal fibers of the ALL, as well as overall ALL injury, was not associated with any other variables (P > .05). Moreover, all patients with associated tibial plateau fractures (9; 18.4%) had abnormality of the proximal fibers of the ALL (P = .033). CONCLUSIONS: ALL injury is highly prevalent among dislocated knees. Most of the injuries are of high grade and involve the proximal, suprameniscal, fibers of the ligament. LEVEL OF EVIDENCE: Level IV, retrospective case series with no comparison group.

Paediatric physeal sparing posterior cruciate ligament (PCL) reconstruction with parental donation allograft: Rationale and operative approach.

BACKGROUND: Paediatric PCL injuries are rare but constitute a significant management challenge. We describe a novel approach to the surgical management of an 11-year-old boy who presented with persisting symptomatic instability following 18months of failed conservative therapy. METHODS: PCL reconstruction was performed using a physeal sparing, all-inside technique under fluoroscopic control. This avoids the potential for iatrogenic growth injury. A parentally donated hamstrings allograft was used to ensure adequate graft size, and reinforced using a non-elastic two millimetre braided suture. Graft reinforcement safeguards against stretching during the early healing phase, but must be removed thereafter to avoid creating a physeal tether. RESULTS: At three months, clinical examination under anaesthesia showed equivalent PCL laxity in the operated knee compared to the normal contralateral knee. The graft reinforcement tape was incised as planned with no change in laxity assessment. Arthroscopic evaluation demonstrated a quiet joint with a well healed graft and no synovitis. Postoperative long leg radiographs showed no growth deformity against preoperative status. CONCLUSION: In paediatric patients with persisting symptomatic instability despite appropriate conservative management, surgical reconstruction of the PCL should be considered. Standard treatment has higher complication rates and poorer graft survival than in an adult cohort. Specific problems include iatrogenic growth plate injury causing growth arrest or angular deformity, inadequate graft size if using hamstrings autograft, and the additional technical challenge of small patient size. Early results from extra-physeal, all-inside PCL reconstruction using a parentally donated allograft are promising and may provide an alternative solution to traditional surgical management.