Arthrofibrosis is a less common complication following anterior cruciate ligament (ACL) reconstruction and there are concerns that undergoing early surgery may be associated with arthrofibrosis. The aim of this study was to identify the patient and surgical risk factors for arthrofibrosis following primary ACL reconstruction. Primary ACL reconstructions prospectively recorded in the New Zealand ACL Registry between April 2014 and December 2019 were analyzed. The Accident Compensation Corporation (ACC) database was used to identify patients who underwent a subsequent reoperation with review of operation notes to identify those who had a reoperation for “arthrofibrosis” or “stiffness”. Univariate Chi-Square test and multivariate Cox regression analysis was performed. Hazard ratios (HR) with 95% confidence intervals (CI) were computed to identify the risk factors for arthrofibrosis. 9617 primary ACL reconstructions were analyzed, of which 215 patients underwent a subsequent reoperation for arthrofibrosis (2.2%). A higher risk of arthrofibrosis was observed in female patients (adjusted HR = 1.67, 95% CI 1.22 – 2.27, p = 0.001), patients with a history of previous knee surgery (adjusted HR = 1.97, 95% CI 1.11 – 3.50, p = 0.021) and when a transtibial femoral tunnel drilling technique was used (adjusted HR = 1.55, 95% CI 1.06 – 2.28, p = 0.024). Patients who underwent early ACL reconstruction within 6 weeks of their injury did not have a higher risk of arthrofibrosis when compared to patients who underwent surgery more than 6 weeks after their injury (3.5% versus 2.1%, adjusted HR = 1.56, 95% CI 0.97 – 2.50, p = 0.07). Age, graft type and concomitant meniscal injury did not influence the rate of arthrofibrosis. Female sex, a history of previous knee surgery and a transtibial femoral tunnel drilling technique are risk factors for arthrofibrosis following primary ACL reconstruction

Background

With the projected 673% increase in total knee arthroplasties (TKA) through the year 2030 in the United States alone, arthrofibrosis will become one of the more commonly encountered challenges in orthopaedic surgery.

Introduction. Arthrofibrosis following total knee arthroplasty (TKA) is a complex and multifactorial complication that may require manipulation under anesthesia (MUA). However, patient and surgical factors that potentially influence the development of knee stiffness following TKA are not fully understood. The purpose of this study was to identify patient and surgical factors that may influence arthrofibrosis following TKA by assessing a cohort of patient that underwent MUA and comparing them to a matched cohort of patients without arthrofibrosis. Methods. The joints registry of a university hospital was searched for patient that underwent MUA following primary TKA between 2004 and 2013. Demographic and surgical information was obtained from the electronic medical record including range of motion (ROM), comorbidities and timing of MUA. Patients who underwent MUA were then double-matched by baseline (prior to primary TKA) knee ROM to patients who underwent primary TKA without postoperative arthrofibrosis during the same time period. Results. Fifty-two patients (56 TKAs, 71% female, mean BMI 32.2kg/m2) underwent MUA after TKA during the study period. MUA was performed a mean of 13.6 weeks after primary TKA. Study patient were then double-matched by baseline flexion (mean 107º±2º) to 111 patients (112 TKAs) with a similar mean baseline flexion (104º±2º, p=0.138). Patient requiring MUA were younger (mean age 56 vs. 64 years, p<0.001), had more comorbidities (5 vs. 3, p<0.001), and a higher number of previous knee surgery (56% vs. 21%, p<0.001) compared with controls. The risk for requiring MUA following primary TKA was significantly higher (2.4, p<0.001) in patient with previous knee surgery (arthroscopy for meniscal pathology, ACL reconstruction, osteotomies). Tourniquet time, length of stay, number of physical therapy sessions, blood loss >50 mL and any complication during the hospital stay were not found to be associated with increased risk of requiring MUA. Discussion. Younger patients with more comorbidities and a history of previous knee surgery were found to have significantly higher risk for developing arthrofibrosis and requiring MUA after primary TKA in the current study. Patients with this risk profile need to counseled regarding the risk for arthrofibrosis possibly requiring MUA after primary TKA

Stiffness after total knee arthroplasty (TKA) is a common problem occurring between 5% and 30% of patients. Stiffness is defined as limited range of motion (ROM) that affects activities of daily living. A recent International Consensus on definition of stiffness of the knee graded stiffness as mild, moderate or severe (90–100, 70–89, <70, respectively) or an extension deficit (5–10, 11–20, >20). Stiffness can be secondary to an osseous, soft tissue, or prosthetic block to motion. Heterotopic bone or retained posterior osteophytes, abundant fibrotic tissue, oversized components with tight flexion or extension gaps or component malrotation can all limit knee motion. Infection should always be considered in the knee that gradually loses motion. Alternative causes include complex regional pain syndrome and Kinesiophobia that can limit motion without an underlying mechanical cause. The evaluation of knee stiffness radiographs of the knee and cross-section imaging should be performed if component malrotation is considered. A metal suppression MRI assists in quantifying the extent of fibrosis and its location in the anterior or posterior compartment of the knee. Inflammatory markers and joint aspiration as indicated to rule out infection. Arthrofibrosis, or post-surgical fibrosis, is related to abnormal scar formation after surgery that leads to loss of motion. The cause of arthrofibrosis is multifactorial and likely related to genetic host factors. Current research is focusing on molecular signatures that may better identify patients at risk. In addition, therapeutic interventions are being studied that best prevent fibrosis and its recurrence and include the use of anti-inflammatories, corticosteroids, Colchicine, biologic medications (IL-1 inhibitors) and low-dose radiation. Early treatment of the stiff TKA includes physical therapy and manipulation under anesthesia (MUA). MUA performed within 3 months may have the greatest increase in ROM but notable improvement can occur up to 6 months after TKA. After six months, arthroscopic or open surgery is recommended for persistent stiffness. Arthroscopic lysis of adhesions can improve ROM greater than 1 year after index TKA. Average improvement of ROM for both MUA and arthroscopic lysis of adhesions (usually in conjunction with MUA) is approximately 30 degrees. The outcome after open lysis of adhesions are reportedly poor but current adjuvant therapies may improve these clinical outcomes as this addresses the biologic, in addition to the mechanical, basis of fibrosis. Component revision performed for component malposition and stiffness has variable outcomes but a recent study reports a mean increase in ROM of 20 degrees and a modest improvement in overall knee function. The cause of post-operative stiffness after TKA is a complex interplay of the patient, surgeon, and post-operative factors. Correct diagnosis of the underlying cause of the stiff total knee is essential to optimizing treatment outcomes. More research in needed in how to best prevent and treat the biologic risk factors and pathways that contribute to post-surgical fibrosis

Introduction. Revision Total Knee Arthroplasty (TKA) is becoming increasingly prevalent as the number of TKA procedures grow in a younger, higher-demand population. Factors associated with patients requiring multiple revision TKAs are not yet well understood. The purpose of this study is to investigate the epidemiology of re-revision TKA, and identify risk factors that are associated with failure of re-revision TKA. Methods. A retrospective analysis was performed on 358 patients who underwent revision TKA at a single institution between 1/2012 and 12/2013. Patients who underwent revision knee arthroplasty two or more times were included. Patients were excluded if their indication for the first revision was periprosthetic joint infection (PJI). Patient demographics, surgical indications, revision details, and available follow-up information were collected. Re-revision failure was defined as the need for any additional operative intervention. A logistic regression analysis was performed to assess for significant predictors of re-revision failure. Results. A total of 66 re-revision TKA patients were included in this study. Mean age at re-revision was 60 (±11 years). There were 48 (73%) females. Mean BMI was 31.8 (±6.9). Median ASA level was 2 (40/59; 68%). Average follow up was 2.1 (±1.0) years, with 68% (45/66) of patients having greater than 2 year follow up (Table 1). The median number of revisions was 2 (range 2–11). The most common indication for re-revision was arthrofibrosis (15; 23%), followed by PJI (14; 21%) and aseptic component loosening (13; 20%). Among re-revision patients, the most common indication of the first revision was aseptic component loosening (17; 30%), followed by arthrofibrosis (16; 28%) and instability (9; 16%) (Table 2). Among the top four indications for re-revision, both the re-revision and initial revision indication were the same. Additionally, 42% of patients possessed the same indication for re-revision as the initial revision. The proportion of patients that had a lateral release performed in either the index procedure or initial revision was higher in re-revisions performed for patellar maltracking (p=0.013). There was a significantly increased risk of re-revision failure if the patient had a higher BMI (OR=1.22; p=0.006). Re-revision survival at 30 days was 92% (60/65), at 1 year was 81% (52/64), and at 2 years 73% (33/45). The indication history of re-revision failure is shown on Table 3. Discussion. Arthrofibrosis and PJI were the most common indications for re-revision. There was an increased risk of re-revision failure in patients with a higher BMI. It was common to have a re-revision TKA for the same indication as the initial revision. A better understanding of the indications and patient factors that are associated with re-revision failures can help align surgeon and patient expectations in this challenging population. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Arthrofibrosis remains a dominant post-operative complication and reason for returning to the OR following total knee arthroplasty. Trauma induced by ligament releases during TKA soft tissue balancing and soft tissue imbalance are thought to be contributing factors to arthrofibrosis, which is commonly treated by manipulation under anesthesia (MUA). We hypothesized that a robotic-assisted ligament balancing technique where the femoral component position is planned in 3D based on ligament gap data would result in lower MUA rates than a measured resection technique where the implants are planned based solely on boney alignment data and ligaments are released afterwards to achieve balance. We also aimed to determine the degree of mechanical axis deviation from neutral that resulted from the ligament balancing technique. Methods. We retrospectively reviewed 301 consecutive primary TKA cases performed by a single surgeon. The first 102 consecutive cases were performed with a femur-first measured resection technique using computer navigation. The femoral component was positioned in neutral mechanical alignment and at 3° of external rotation relative to the posterior condylar axis. The tibia was resected perpendicular to the mechanical axis and ligaments were released as required until the soft tissues were sufficiently balanced. The subsequent 199 consecutive cases were performed with a tibia-first ligament balancing technique using a robotic-assisted TKA system. The tibia was resected perpendicular to the mechanical axis, and the relative positions of the femur and tibia were recorded in extension and flexion by inserting a spacer block of appropriate height in the medial and lateral compartments. The position, rotation, and size of the femoral component was then planned in all planes such that the ligament gaps were symmetric and balanced to within 1mm (Figure 1). Bone resection values were used to define acceptable limits of implant rotation: Femoral component alignment was adjusted to within 2° of varus or valgus, and within 0–3° of external rotation relative to the posterior condyles. Component flexion, anteroposterior and proximal-distal positioning were also adjusted to achieve balance in the sagittal plane. A robotic-assisted femoral cutting guide was then used to resect the femur according to the plan (Figure 2). CPT billing codes were reviewed to determine how many patients in each group underwent post-operative MUA. Post-operative mechanical alignment was measured in a subset of 50 consecutive patients in the ligament balancing group on standing long-leg radiographs by an independent observer. Results. Post-operative MUA rates were significantly lower in the ligament balancing group (0.5%; 1/199) than in the measured resection group (3.9%; 4/102), p=0.051. 91.3% (42/46) of knees were within 3° and 100% (46/46) were within 4° of neutral alignment to the mechanical axis post-operatively in the ligament balancing group. Conclusions. Gap driven femoral based planning in TKA resulted in a significantly lower post-operative manipulation rate than in the measured resection approach, while maintaining acceptable overall alignment to the mechanical axis

The process by which pathologic scar tissue forms after TKA and restricts functional range of motion is relatively poorly understood. Arthrofibrosis may develop in patients who have normal intra-operative range of motion (ROM). However, passive flexion, extension, or both can become restricted and painful, sometimes several weeks after surgery following an early post-operative period of normal motion. The response to both nonsurgical and surgical treatment is often unsatisfactory. Arthrofibrotic scar contains dense fibrous tissue with abundant fibroblasts. Heterotopic bone is frequently found in patients with arthrofibrosis. Stiffness may result from inadequate postsurgical pain management or rehabilitation or from a biologic process that causes rapid proliferation of scar tissue. Genetic factors also may play a role, although it is difficult to predict which patients are at increased risk for arthrofibrosis after TKA. Surgical technique also can contribute; oversizing the femoral component, overstuffing the patella, or rotational malalignment can play a role. Manipulation can be helpful, particularly during the first three months after surgery. However, maintaining motion long term also requires an effective pain management and physical therapy program after manipulation. Arthroscopy may also have a role to remove scar tissue in the suprapatellar pouch and medial and lateral gutters usually between six months and one year after TKA. After one year following TKA, open surgical release or revision surgery is the most effective method to increase motion. However, only modest gains are likely to be achieved and pain may not be improved

INTRODUCTION. Use of a novel ligament gap balancing instrumentation system in total knee arthroplasty (TKA) resulted in femoral component external rotation values which were higher on average, compared to measured bone resection systems. In one hundred twenty knees in 110 patients the external rotation averaged 6.9 degrees (± 2.8) and ranged from 0.6 to 12.8 degrees. The external rotation values in this study were 4° and 2° larger, respectively, than the typical 3° and 5° discrete values that are common to measured resection systems. The purpose of the present study was to determine the effect of these greater external rotation values for the femoral component on patellar tracking, flexion stability and function of two different TKA implant designs. METHODS. In the first arm of the study, 120 knees in 110 patients were consecutively enrolled by a single surgeon using the same implant design (single radius femur with a medial constraint tibial liner) across subjects. All patients underwent arthroplasty with tibial resection first and that set external rotation of the femoral component based upon use of a ligament gap balancing system. Following ligament tensioning / balancing, the femur was prepared. The accuracy of the ligament balancing system was assessed by reapplying equal tension to the ligaments using a tensioning bolt and torque wrench in flexion and extension after the bone resections had been made. The resulting flexion and extension gaps were then measured to determine rectangular shape and equality of the gaps. Postoperative Merchant views were obtained on all of the patients and patellar tracking was assessed and compared to 120 consecutive total knee arthroplasties previously performed by the same surgeon with the same implant using a measured resection system. In the second arm of the study, 100 unilateral knees in 100 patients were consecutively enrolled. The same instrumentation and technique by the same surgeon was used, but with a different implant design (single radius femur without a medial constraint tibial liner). RESULTS. Rectangular flexion and extension gaps were obtained within ± 0.5mm in all cases. Equality of the flexion and extension gaps was also obtained within ± 0.5mm in all cases. Merchant views of the total knee arthroplasties showed central patellar tracking with no tilt or subluxation in 90% of the ligament gap balanced knees and 74% of the measured resection knees. Arthrofibrosis resulting in a closed manipulation under anesthesia was required in 6% of the knees with single radius femurs and medial constaint tibial liners, but only in 1% of the single radius femur knees without medial constraint liners. DISCUSSION AND CONCLUSION. External rotation values are higher on average, when ligament tensioning / balancing is employed with this novel system compared to measured resection systems. In this study this resulted in consistent matching of the flexion gap to the extension gap and better patellar tracking. These findings suggest that limiting the surgeon to discrete rotation values may be at odds with where the femur “desires” to be, given soft tissue considerations for each patient. Also, even with ideal soft tissue balancing, TKA implant design can have a significant affect on the outcome measure of development of arthrofibrosis