Recurrent dislocation of total knee arthroplasty: an unusual cause

Recurrent Left Periprosthetic Posterior Knee Dislocation in an Elderly Woman With Dementia and Altered Mental Status: A Case Report

The case presented in this article is one of recurrent left posterior periprosthetic knee dislocation (PPKD) in a patient with altered mental status (AMS). The patient, a 69-year-old female with a complex medical history including dementia, Ménière's syndrome, and left total knee arthroplasty, presented to the emergency department with AMS whereupon a left PPKD was discovered. Less than three weeks before this presentation, she sustained a left PPKD during a previous admission. During her current admission, she sustained yet another left PPKD after trials of closed reduction and immobilization. The patient eventually underwent a left cemented revision total knee arthroplasty with a hinged prosthesis. The implant was noted to be stable, and the patient had minimal pain postoperatively with no vascular or neurological injury. Upon outpatient follow-up, the patient reported doing well. There have been few documented cases of recurrent or chronic PPKD in individuals with AMS or restricted intellect. These comorbidities create a complex approach to diagnosing and treating the aforementioned orthopedic injury, and as this injury can have devastating consequences, quickly and effectively delivering diagnosis and treatment is vital. This case highlights the importance of early identification, risk factors, preoperative management, and appropriate operative course for patients with AMS and recurrent PPKDs.

A novel technique of reshaping the post of a constrained liner to avoid post and primary box mismatch in a case of recurrent dislocation after total knee arthroplasty

Knee dislocation after total knee arthroplasty, although rare, is a dangerous injury that can lead to neurovascular compromise and permanent disability. With the increase in number of total knee arthroplasty, more and more cases of dislocations are being reported. We describe a novel technique of reshaping the post of a constrained liner to fit into the box of a vanguard primary knee system in a patient with recurrent posterior knee dislocation after a PS TKA with a follow-up of 5 years.

Tibiofemoral Dislocation After Total Knee Arthroplasty

BACKGROUND

Tibiofemoral dislocation after total knee arthroplasty (TKA) is a rare complication. Published case reports describe fewer than 6 patients, making conclusions about the etiology, epidemiology, complications, and treatment of tibiofemoral dislocation difficult. This case series highlights common demographic features, potential causes, and difficulties during the management of tibiofemoral dislocations after TKA.

METHODS

Between 2005 and 2014, 14 patients presented to our institution with a tibiofemoral dislocation. Patients were excluded if they had patellofemoral dislocation or subluxation without a tibiofemoral dislocation. We retrospectively reviewed patient demographics, time to first dislocation, number of dislocations, time to surgical intervention, complications, and potential etiologies of tibiofemoral dislocation.

RESULTS

Twelve of 14 patients were female. Their mean body mass index was 33 ± 10 kg/m(2). Thirteen of 14 patients had a mean of 2.0 ± 1.4 dislocations. Four patients dislocated due to polyethylene damage and 5 due to ligamentous incompetence. Twelve of 14 patients required open surgical intervention. Complications in this patient population were common with 3 cases of infection, 7 cases of multiple dislocation, 2 cases of popliteal artery laceration, 1 case receiving a fusion, and 1 case receiving an amputation.

CONCLUSION

Patients with tibiofemoral dislocation after TKA are predominantly obese, female, and have a high risk for complications. They dislocate predominantly because of polyethylene damage or ligamentous incompetence. Re-dislocation is common if treated with closed reduction alone.

Simultaneous posterior dislocation of primary total knee arthroplasty with ipsilateral tibial shaft fracture: A case report and review of literature

Dislocation following total knee arthroplasty (TKA) is a rare but serious complication. Here, a 74-year-old woman with posterior dislocation of her right cruciate-retaining TKA and ipsilateral tibia diaphysis fracture was presented. She only slipped down on the ground with a quick twist of her right leg. She underwent revision semiconstrained TKA and osteosynthesis of tibial fracture with plate and screw. Her partially avulsed patellar tendon was repaired as well. She was ambulatory with a cane and satisfied with revision operation at last control. Extensor mechanism and functional posterior cruciate ligament is especially important in patients receiving cruciate-retaining TKA. As far as we know, simultaneous dislocation of TKA with fracture of tibia diaphysis has never been reported before.

Case report: Total knee arthroplasty polyethylene liner disengagement identified by arthrography

We report a case of total knee arthroplasty polyethylene liner disengagement identified by plain film arthrography and CT arthrography.

Results of revision surgery and causes of unstable total knee arthroplasty

Background

The aim of this study was to evaluate causes of unstable total knee arthroplasty and results of revision surgery.

Methods

We retrospectively reviewed 24 knees that underwent a revision arthroplasty for unstable total knee arthroplasty. The average follow-up period was 33.8 months. We classified the instability and analyzed the treatment results according to its cause. Stress radiographs, postoperative component position, and joint level were measured. Clinical outcomes were assessed using the Hospital for Special Surgery (HSS) score and range of motion.

Results

Causes of instability included coronal instability with posteromedial polyethylene wear and lateral laxity in 13 knees, coronal instability with posteromedial polyethylene wear in 6 knees and coronal and sagittal instability in 3 knees including post breakage in 1 knee, global instability in 1 knee and flexion instability in 1 knee. Mean preoperative/postoperative varus and valgus angles were 5.8°/3.2° (p = 0.713) and 22.5°/5.6° (p = 0.032). Mean postoperative α, β, γ, δ angle were 5.34°, 89.65°, 2.74°, 6.77°. Mean changes of joint levels were from 14.1 mm to 13.6 mm from fibular head (p = 0.82). The mean HSS score improved from 53.4 to 89.2 (p = 0.04). The average range of motion was changed from 123° to 122° (p = 0.82).

Conclusions

Revision total knee arthroplasty with or without a more constrained prosthesis will be a definite solution for an unstable total knee arthroplasty. The solution according to cause is very important and seems to be helpful to avoid unnecessary over-constrained implant selection in revision surgery for total knee instability.

High early failure rate of the Columbus posterior stabilized high-flexion knee prosthesis

BACKGROUND

Most studies report high survivorship rates for TKAs, however, we observed higher than anticipated rates of dislocation and femoral component loosening after implanting a Columbus posterior stabilized prosthesis.

QUESTIONS/PURPOSE

We therefore determined (1) the incidence of dislocation and aseptic loosening that occurred after implantation of posterior stabilized high-flexion prostheses in TKAs, (2) the causative factors of dislocation and aseptic femoral component loosening when comparing two designs of prostheses, and (3) the mechanisms of dislocation.

METHODS

We retrospectively reviewed 319 patients who underwent 384 TKAs from May 2007 to July 2008. These patients had been assigned alternately to receive a Scorpio posterior stabilized knee prosthesis (Group I, 158 patients, 187 knees) or a Columbus posterior stabilized knee prosthesis (Group II, 161 patients, 197 knees). We followed the patients with clinical and radiographic evaluations for a minimum of 24 months (mean, 26 months; range, 24-38 months). Ten retrieved prostheses were examined visually.

RESULTS

Ten dislocations (5.1%; 10 of 197 knees) and seven aseptic loosenings of femoral components (3.6%; seven of 197 knees) occurred in Group II at a mean of 10.9 months postoperatively. However, no dislocation or loosening occurred in patients in Group I. Most dislocations were associated with varus flexion or flexion rotation movements during normal daily activities. The cam jump distance at 90º flexion for the Columbus prosthesis was lower than for the Scorpio prosthesis.

CONCLUSIONS

We observed a high rate of early failure during short-term followup after implantation of a Columbus posterior stabilized prosthesis. It appears that early failures of the Columbus design were related to a different cam-post design attributable to a low jump distance during knee flexion. We no longer recommend using this device.

LEVEL OF EVIDENCE

Level II, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.

Anterior dislocation after a posterior stabilized total knee arthroplasty

Dislocation of a total knee arthroplasty is a rare but serious complication. In previous literature, when dislocation does occur, it is usually in the posterior direction in cases with a posterior stabilized total knee arthroplasty due to cam jump. We report an unusual case of anterior dislocation of an 11-year-old posterior stabilized total knee arthroplasty in a 55-year-old woman with rheumatoid arthritis occurred after a slip.

How to treat a tibial post fracture in total knee arthroplasty? A systematic review

BACKGROUND

Posterior-stabilized TKAs, which use a polyethylene tibial post to articulate against a metal femoral cam, are used regularly. Reported complications are related to the patellofemoral articulation or the tibial post-cam mechanism. Fracture of the tibial post is an uncommon but disabling complication after posterior-stabilized TKA that requires operative treatment.

QUESTIONS/PURPOSES

The literature was reviewed to determine the frequency of tibial post fracture and address three questions: (1) Is there a specific prosthetic design or patient demographics in knees with a fracture of the tibial post? (2) What are the common presenting complaints and methods of diagnosis? (3) What methods of treatment have been used?

METHODS

A PubMed search of English language articles from February 1982 to April 2010 was performed and 20 articles, all Level IV studies, were identified.

RESULTS

One specific design of posterior-stabilized tibial post with a central screw hole had a 12.4% incidence of fracture. Tibial post fracture has been reported with other designs, but with an incidence of 1% or less. The most common presenting symptoms include effusion, instability, or patella clunk syndrome. The most common method of diagnosis was clinical examination followed by arthroscopic examination. Treatment with revision to a new tibial polyethylene liner generally has been successful at short-term followup.

CONCLUSIONS

Tibial post fracture is a relatively uncommon complication after posterior-stabilized TKA that usually is treated successfully with liner exchange. The low quality of available literature makes it difficult to recommend a specific treatment protocol.

Highly crosslinked polyethylene in posterior-stabilized total knee arthroplasty: in vitro performance evaluation of wear, delamination, and tibial post durability

Recent advances in total knee arthroplasty (TKA) include the development of highly crosslinked polyethylene (HXPE). To assess the suitability of using HXPE in posterior-stabilized TKA, knee simulator wear testing and a novel tibial post durability test were performed on a modern posterior-stabilized implant design with both conventional polyethylene (CPE) and HXPE materials. The laboratory testing reproduced clinically relevant wear and tibial post damage mechanisms. For the designs tested, wear volume was reduced by 67% to 75% for aged HXPE compared with aged CPE. Components of HXPE also demonstrated superior tibial post durability compared with the CPE design, despite the use of unaged material to represent best-case CPE tibial post strength. With appropriate design considerations, HXPE can be successfully incorporated into a posterior-stabilized TKA.

Two stage fracture of a polyethylene post in a 9-year-old posterior-stabilized knee prosthesis: a case report

Introduction

Several cases of tibial post breakage are reported in the literature. To the best of our knowledge, only three cases of NexGen knee prosthesis (Zimmer, Warsaw, Indiana, USA) tibial post failure have been reported.

Case presentation

In November 1999, a 63-year-old Caucasian woman from Italy with a history of symptomatic left knee osteoarthritis underwent a total knee arthroplasty. In March 2008, while rising from a chair, she felt a sudden pain and instability in her left knee. She reported a fracture of the polyethylene post of the tibial insert. No malposition or malalignment of either the femoral or tibial components were identified. The polyethylene tibial insert was studied under light microscopy and scanning electron microscopy. The fracture was also noted to have occurred without any notable polyethylene wear.

Conclusion

Scanning electron microscopy revealed two different damage patterns that could be explained with a two-stage rupture of our patient's polyethylene post. This could have been caused by a non-optimal ligamentous balancing during first implant surgery. Her knee probably developed a varus instability that weakened the post, and then a posterior anterior stress finally broke the polyethylene.

Dislocation following total knee arthroplasty: A report of six cases

BACKGROUND

Dislocation following total knee arthroplasty (TKA) is the worst form of instability. The incidence is from 0.15 to 0.5%. We report six cases of TKA dislocation and analyze the patterns of dislocation and the factors related to each of them.

MATERIALS AND METHODS

Six patients with dislocation of knee following TKA are reported. The causes for the dislocations were an imbalance of the flexion gap (n=4), an inadequate selection of implants (n=1), malrotation of components (n=1) leading to incompetence of the extensor mechanism, or rupture of the medial collateral ligament (MCC). The patients presented complained of pain, giving way episodes, joint effusion and difficulty in climbing stairs. Five patients suffered posterior dislocation while one anterior dislocation. An urgent closed reduction of dislocation was performed under general anaesthesia in all patients. All patients were operated for residual instability by revision arthroplasty after a period of conservative treatment.

RESULTS

One patient had deep infection and knee was arthrodesed. Two patients have a minimal residual lag for active extension, including a patient with a previous patellectomy. Result was considered excellent or good in four cases and fair in one, without residual instability. Five out of six patients in our series had a cruciate retaining (CR) TKA designs: four were revised to a posterior stabilized (PS) TKA and one to a rotating hinge design because of the presence of a ruptured MCL.

CONCLUSION

Further episodes of dislocation or instability will be prevented by identifying and treating major causes of instability. The increase in the level of constraint and correction of previous technical mistakes is mandatory.

Intraoperative fractures and ligament tears during total knee arthroplasty. A 1795 posterostabilized TKA continuous series

INTRODUCTION

Intraoperative fractures are a reported complication during the course of primary total knee replacement. Major ligament disruptions can also occur. Clinical data are lacking to tell how much these incidents affect implantation quality and outcome.

HYPOTHESIS

A thorough knowledge of these occasional incidents helps proper decision making when confronted to such situations at surgery.

MATERIALS AND METHODS

This report is based on a series of primary, posterostabilized total knee arthroplasties (posterostabilized, mobile bearing TKA with a third median condyle from Tornier Laboratory). We studied all possible mechanical complications that developed during the course of arthroplasty and analyzed their cause. We compared the functional results of patients presenting these complications to those of the total series and to data from the literature. The entire operative reports for the 1795 TKA performed during this study were available and evaluated. A clinical and radiological review was performed for 1624 patients at an average follow-up time of 36.8+/-34 (2-193) months.

RESULTS

At this last follow-up, the average International Knee Society (IKS) score was 91.2 (19-100) and the function score was 77.76 (0-100). One hundred and thirty-two patients were deceased (unrelated to TKA) at this last follow-up evaluation. A total of 69 mechanical complications were accounted for at the time of surgery (3.8%): 40 definite fractures or fissures around the knee (2.2%), 29 tendon or ligament disruptions or attenuations (1.6%). The risk of tibial cracks was statistically more significant, with the smaller sizes tibial trays (size 1) (p=0.019) or when an anterior tibial tuberosity elevation had been performed (p=0.02). Survival curve analysis (at an average seven and a half-years postoperative follow-up) showed that all prosthetic components were still present in 93.3% of cases in the series of patients with these peroperative complications, and in 93.8% of cases in the series of patients without these intraoperative complications; this survival rate amounted to 91.9% of cases at an average 16-years postoperative follow-up.

CONCLUSION

This large, homogeneous series of primary, posterostabilized TKA took on 3.8% of intraoperative bone or ligament complications. All these complications could be prevented by a rigorous surgical technique. The improvement of ancillary materials, the saws, and good knowledge of such complications by the surgeon are essential.

LEVEL OF EVIDENCE

Level IV. Therapeutic Study.

Managing skin necrosis and prosthesis subluxation after total knee arthroplasty

Skin necrosis and prosthetic subluxation are dreaded complications after total knee arthroplasty. It can result in deep infection with subsequent failure of prosthesis. The incidence of infection in patients with rheumatoid arthritis who undergo knee arthroplasty is high when compared to patients with primary osteoarthritis. The gastrocnemius muscle flap has been described for cover of proximal tibia and tendon loss because of malignancy and has been used as a bridge graft in trauma patients with patellar tendon loss. We describe a patient with total knee arthroplasty with anterior knee skin necrosis and prosthesis subluxation because of attenuation and loss of continuity of patellar tendon. This was managed by using gastrocnemius bridge grafting. Here, the gastrocnemius bridge graft was used as a soft tissue cover as well as a dynamic anterior stabilizer for the prosthesis.

Kinematic analysis of kneeling in cruciate-retaining and posterior-stabilized total knee arthroplasties

Kneeling is an important function of the knee for many activities of daily living. In this study, we evaluated the in vivo kinematics of kneeling after total knee arthroplasty (TKA) using radiographic based image-matching techniques. Kneeling from 90 to 120 degrees of knee flexion produced a posterior femoral rollback after both cruciate-retaining and posterior-stabilized TKA. It could be assumed that the posterior cruciate ligament and the post-cam mechanism were functioning. The posterior-stabilized TKA design had contact regions located far posterior on the tibial insert in comparison to the cruciate-retaining TKA. Specifically, the lateral femoral condyle in posterior-stabilized TKA translated to the posterior edge of the tibial surface, although there was no finding of subluxation. After posterior-stabilized TKA, the contact position of the post-cam translated to the posterior medial corner of the post with external rotation of the femoral component. Because edge loading can induce accelerated polyethylene wear, the configuration of the post-cam mechanism should be designed to provide a larger contact area when the femoral component rotates.

Failure of a metal-reinforced tibial post in total knee arthroplasty

Failures of the polyethylene tibial post in posterior stabilized total knee arthroplasty are usually associated with pain and knee instability. We report an unusual presentation of a tibial post failure that occurred after the polyethylene insert was revised in a posterior-stabilized total knee. The tibial post on the revised insert broke off, exposing a metal reinforcing pin. During the resulting posterior subluxations of the tibia, the metal pin articulated against the cam on the femoral component, resulting in the generation of metallic debris in the knee joint.

Anteroposterior stability in posterior cruciate ligament-retaining total knee arthroplasty

Anteroposterior stability was evaluated using a KT-2000 arthrometer in 18 patients (21 knees) continuously for up to 5 years after posterior cruciate ligament-retaining total knee arthroplasty. The Knee Society score, functional score, and the maximum flexion angle did not change significantly during the postoperative period. The mean anteroposterior displacement of all joints studied at both 30 degrees and 75 degrees of flexion did not change significantly during the 5-year period of observation, but 4 individual knees did exhibit increases in anteroposterior displacement of 3 mm or more. One of the 4 knees exhibited osteolysis beneath the tibial component. Three of these knees had undergone high tibial osteotomy at some time before the total knee arthroplasty.