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10 Articles in Volume 14, Issue #3
Practical Guide To Safe Use of Nonprescription Pain Medications
Common Causes of Acute Abdominal Pain
Early Treatment of TMD May Prevent Chronic Pain and Disability
Insomnia: Focus on New Dosing Concerns In Women
Is Marijuana Use Associated With Non-adherence To Opioid Therapy—Insights Gained From Urine Drug Monitoring
New Evidence-Based Diagnosis Criteria for TMD
New Rating Scale Helps Evaluate Refractory Chronic Migraine Patients
The Effect of Prolonged Knee Extension Immobilization on Knee Active Range of Motion: A Case Study on Arthrofibrosis
Opioid Bias Hurts Pain Patients
Can misoprostol be used for refractory chronic constipation?

The Effect of Prolonged Knee Extension Immobilization on Knee Active Range of Motion: A Case Study on Arthrofibrosis

History

A 71-year-old female presented to our physical therapy clinic with postoperative right knee pain, stiffness, and weakness after suffering a severe, high-energy hyperextension-type injury to the knee on January 29, 2013. The postoperative report that included a description of the injury confirmed rupture of the medial collateral ligament (MCL), lateral collateral ligament (LCL), and posterior cruciate ligament (PCL), along with tearing of the posterior tibial artery at the level of the popliteal fossa. The patellar tendon and patella both suffered damage as well but to a lesser extent. Figure 1 shows the anatomy of the knee.

The patient underwent emergency surgery a few hours after the accident, with the vascular event taking precedence, followed by the orthopedic reconstruction of the PCL and MCL ligaments. The LCL was left unrepaired. The patient’s knee was immobilized using external fixation device (outrigger) to allow the patella and extensor mechanism to heal without further incident. The outrigger device was worn by the patient for 12 weeks after the surgery (Figure 2).

In early February 2013, she went to a rehabilitation facility for 1 week to begin early-phase physical therapy followed by home rehabilitation for the next 9 weeks. This involved home care services including physical therapy. On May 20, 2013, the patient had the stabilizing hardware removed and was fitted with an immobilizer brace locked at zero degrees extension, which weeks later, was followed with a hinged brace that could accommodate gradual knee flexion range of motion. At this time, the patient was using a wheelchair to get around. She was also referred to outpatient physical therapy to improve strength and mobility of the knee.

Physical Examination

The patient presented to outpatient physical therapy with an orthopedic prescription to treat right knee pain, weakness, and limited active range of motion (AROM). The clinical exam revealed a 15-degree arc of available motion in knee flexion (ie, AROM flexion 15, extension 0 [normal]) in the right knee. The knee was mildly swollen, primarily in the supra-patellar pouch, and had mild to moderate tender areas, including the LCL, MCL, quadriceps/patellar tendons, and posterior knee joint. The tenderness correlated with the areas of injury and subsequent surgical repair, along with contact points from her hinged brace.

The most striking functional deficit in this particular case was the knee flexion range of motion loss that resulted from “positional gelling” secondary to post surgical scarring/fibrosis as a result of protracted immobilization in knee extension. Although there were deficits in other domains such as strength, balance, and gait, the most dramatic loss was definitely in knee joint motion. As she started physical therapy, she was wheelchair bound due to lack of right knee mobility and pain, leading to weakness on the right side. Weakness in her case had a twofold origin: neurologically mediated reflex inhibition caused by both edema in the joint and nociceptive input, and atrophic changes in muscle tissue as measured by girth differences between the 2 limbs. The culmination of the 2 factors manifested as weakness of the quadriceps, hamstring, hip adductors, and hip abductors, with resultant decreases in general motor control.

As a result of poor knee motor control, the patient had problems in both gait and dynamic balance, with both domains needing attention and inclusion in the care plan. At the time of intake (first visit), strength scores were documented as 2+/5 for quadriceps and 3- for hamstrings. The “red flag” was clearly the gross limitation in knee flexion that had been caused by positional locking of the knee in extension for long periods of time (Figures 3-5). The trade off made by the orthopedic and vascular team (stability over mobility) optimized the environment for subsequent knee soft tissue contracture. Indeed, both the posterior tibial artery and the soft tissue structures (ligaments and tendons) that were injured would require a lengthy period of immobility to ensure biological healing. The downside in this management plan is that postoperative immobilization (outrigger/bracing), which is designed to protect the repaired elements, can have a devastating effect on collagen-based elements of the knee. This will require force loading (mechanobiology) in cycles of stretching and shortening, which is critical to mobility and, ultimately, functional recovery down the line.


Differential Diagnosis

Our treatment approach evolved from a shared team perspective that was shaped by the context of the case presentation: the knee had suffered catastrophic musculoskeletal injury that required extensive surgical interventions, which later necessitated a prolonged exposure time (14 weeks) of immobilization in knee extension.

At approximately 2 months into physical therapy, the patient’s progress leveled off. During those 2 months progress was slow and steady until it abruptly halted. Continued manual passive range of motion (PROM) exer-cises began to cause pain and swelling. Shorter but more aggressive bouts of flexion PROM efforts resulted in knee joint irritation leading to edema and motor control inhibition. We tried to vary both the duration and magnitude of applied stretch force to the knee, consistent with our understanding of collagen creep. The idea of prolonged low force application for extended periods of time is the rationale behind dynamic tension devices where both force and time of application can be controlled by the patient. This intervention yielded no net gains in AROM in flexion beyond what we previously achieved with manual PROM methods. Her symptoms (pain, swelling, tenderness, redness) were clearly being exacerbated by persistent passive stretch to the knee and she identified the medial joint line and quadriceps/patellar tendon extensor mechanism as tender/pain sites during stretching. Table 1 lists possible differential diagnoses.

Final Diagnosis

The primary lesion and main obstacle to mobility progression was a thick, taut (palpable) band of scar tissue (arthrofibrosis), which was confirmed (verified and measured) using ultrasonography.

Treatment

From May to August 2013, the patient was diligent with physical therapy that included therapeutic exercises for lower extremity strengthening and knee stabilization, along with ultrasound and ice after exercises to reduce activity-induced inflammation. When the knee was able to reach 80 degrees flexion, it became apparent that it was not going to give any further. At that point we changed tack and concentrated primarily on gaining motion and began to apply high-level acoustic compression therapy. The rationale for choosing this treatment was to weaken or break down the offending scar tissue that was binding up the extensor mechanism of the knee and causing the extension contracture. When this failed, we reverted to dynamic flexion splinting for approximately 1 month. This also failed—the contracture was deep and had set.

The patient had been through extensive and oftentimes painful physical therapy sessions, but the motion restriction continued. We advised the patient to rest for the next 6 weeks, and she was referred to another orthopedic surgeon who recommended an arthrolysis or surgical excision of the fibrotic band causing the restriction. In October 2013, she underwent arthroscopic arthrolysis and manipulation under anesthesia and recovered from the procedure without incident.

In early November 2013, the patient restarted physical therapy using the usual therapeutic exercises for strengthening/stabilization, along with aggressive PROM followed by cold laser and ice to control post-exercise-induced tissue irritation and swelling. By early January 2014, the patient had regained most of her flexion ROM (120 degrees), which represented just over 90% of ideal based on her contralateral side. Sometime during this final phase of rehab, she was put into a knee brace to protect the unrepaired lateral ligament structure (LCL brace, Figure 6).

Discussion

We chose to highlight this case for several reasons—most importantly, to emphasize the need to coordinate between conservative and surgical interventions. Physical therapy alone can successfully treat many conditions, or, at least help the patients better manage a problem without the need for surgery—but not always. When it comes to treating the 5% to 15% of postsurgical reconstruction and arthroplasty knee patients who go on to develop arthrofibrosis, physical therapy (manual PROM) might not be enough, and often the patient will require surgical assistance in the form of manipulation under anesthesia (MUA), arthroscopic debridement, and/or the more popular arthroscopic arthrolysis. This latter procedure involves surgically dissecting problematic scar tissue.

If we apply what we already know about the condition of arthrofibrosis, it becomes imperative that patients begin PT as early as possible after a knee surgery, especially in patients who have developed scar tissue at a faster pace than normal (hyper-scarring). There appears to be a possible genetic predisposition to hyper-scarring, and it is not necessarily incident-specific, meaning if a patient developed arthrofibrosis after a first knee reconstructive procedure, there is an increased likelihood and probability that they will develop the same problem in a subsequent surgery.There are, however, what appear to be factors that can either add or detract from the likelihood of early pathologic postsurgical scarring.

Arthrofibrosis has been scientifically linked to diabetes, juvenile rheumatoid arthritis, ankylosing spondylitis, and complex regional pain syndrome (CRPS).1 If a patient has one of these conditions, and they undergo major knee surgery, there is a statistically greater chance of that patient developing arthrofibrosis after surgery.

In bilateral total knee arthroplasty (TKA) cases that were done simultaneously, the appearance of arthrofibrosis in both knees were similar in pattern of occurrence (incidence) to cases where the patient had each knee operated on at different times and by different surgeons. In both scenarios, more often than not, we see arthrofibrosis develop bilaterally, but the severity of the condition appears to be modified by either the surgeon (technique, implant choice, etc.), or the temporal factor, or both. The rehabilitation factor was controlled because patients were coming to the same therapist, who applied the same protocol to the knees in both scenarios.

Another interesting observation is that patients who are put on therapeutic warfarin (blood thinner) after knee surgery have a greater chance of developing arthrofibrosis than patients not put on warfarin or another anticoagulant.2

 Conclusion

When managing a traumatic postsurgical knee arthroplasty or reconstruction patient, clinicians should keep in mind some general guidelines—specifically, the timeline for the application of certain therapies. In light of the evidence suggesting that prophylactic anticoagulation therapy plays a role in increasing the likelihood of joint arthrofibrosis, physicians will need to perform a risk-benefit analysis on each patient and then make that determination. In patients who are predisposed to scarring, it is imperative that aggressive PROM begins immediately after surgery. Dynamic tension splinting can gain another 25 degrees of ROM, on average.3 Therefore, if the therapist can get a patient’s knee flexion score to 95 degrees, the tension splint might then be able to move the knee to that functional 115 degree benchmark. Timing is everything, and to prevent further surgical interventions, the involved knee should get to the 95-100 degree flexion mark by approximately week 6 (post surgery) to optimize the odds of not needing invasive interventions to achieve functional status of 115-degree knee flexion minimum (Figure 7).

The main point is the sooner we meet these benchmarks, the better the outcome for the patient. If conservative methods fail, there are promising alternative interventions, including arthrolysis, which addresses the arthrofibrotic lesion through dissection. Unfortunately, the predisposing factors that exist for the initial surgery tend to remain for any subsequent procedures. Therefore, scarring after surgery will be expected to occur after arthrolysis as well; hence, in these cases surgical and rehab providers will need to closely coordinate the patient’s surgical and physical therapy care plan.

 

Last updated on: May 5, 2014
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