Background

Total Knee Arthroplasty (TKA) provides patients with significant improvements in quality of life. Subjective patient reported outcome measures (PROMs) are traditionally used to measure preoperative functional status and postoperative outcomes. However, there are limitations to PROMs. In particular, they provide virtually no functional information in the first 3 weeks after surgery, which could be used to guide the patient's recovery. Newly available wearable electronic sensors make it possible to: 1) measure important functional outcomes following TKA; 2) guide the patient's physical therapy (PT); and 3) provide real-time functional and clinical information to the provider.

Compliance with PT after TKA is a challenge. Patients cite time, transportation, and cost as deterrents to PT appointments. However, an intensive PT program is essential in TKA. Surface sensor devices may be able to increase PT compliance by guiding patients through exercises at home. Additionally, these devices can transmit PT progress in real-time to the providers, allowing them to monitor and assist the patient's recovery.

Our study investigates the feasibility of using a surface sensor device (TracPatch™) on patients following TKA. We sought to answer the following questions: 1) Will patients tolerate the device; 2) Will patients comply with device instructions; 3) Will patients be able to use the smart phone application; 4) Will the device collect, transmit, and store data as it was designed? We believe these fundamental questions must be answered as we enter the era of personal sensor-measured functional outcomes.

Background

Total hip arthroplasty (THA) is a highly successful procedure, yet access to arthroplasty is limited in many developing nations. In response, organizations around the world have conducted service trips to provide international arthroplasty care to underserved populations. Little outcomes data are currently available related to these trips. We present a 1-year follow up.

Background

Total hip replacement is a highly successful procedure, yet access to arthroplasty is limited in many developing nations. In response, organizations in the United States have conducted service trips to provide international arthroplasty care to underserved populations. Little outcomes data are currently available related to these trips. We aimed to assess patient outcomes following total hip arthroplasty performed on a surgical mission trip.

Introduction

Neck-stem corrosion has been associated with Adverse Local Tissue Reaction (ALTR) in dual-taper femoral stems. Several diagnostic tests, of varying specificity and sensitivity, are used to identify ALTR. The purpose of this study was to document the clinical presentation, diagnostic workup and surgical findings in a large cohort of patients with dual modular stems, and use this information to propose an evaluation protocol that assists surgical decision-making.

Introduction:

The addition of neck-stem modularity of femoral components allowed for increased versatility in controlling stability, head center, and limb length in total hip arthroplasty (THA). Recent reports of neck-stem corrosion, complicated by adverse local tissue reaction, have raised concern and prompted further patient evaluation for revision arthroplasty.

The most reported benefit of TKA navigation technologies has been the reduction in limb and component alignment outliers. This improvement has not been shown to effect clinical outcomes. This study was designed to compare the functional outcomes between computer assisted techniques and manual techniques.

Each group had 60 patients with similar demographics. The average functional outcomes (SF-36, WOMAC, range of motion, pain relief, and knee society score) were the same.

The average scores of the SF-36, Knee Society Score, WOMAC were similar for the two groups. However, fewer patients in Group II reported visual analog pain scores greater than 40 at 6 wks, 3 mos and 6 mos. At 1 yr, the pain scores of the two groups were similar. Fewer patients in Group II had KSS scores less than 70 at 3 months, 80 at 6 months, and 90 at one year, than those in Group I. The average range of motion in Group II was greater by 8 degrees at 4 wks and 3 mos, but equal to the average ROM in Group I at 6 and 12 mos. However, the number of patients with less than 90 degrees of motion at each follow-up period was less in Group II than in Group I at each follow-up period. There were fewer superficial wound infections in Group II than in Group I.

The average functional outcomes were similar; the results indicate a consistent reduction in outliers in most measured parameters of functional outcomes. In particular, the guidelines for administering pain medication and providing physical therapy were similar for the two groups. The results of this study are parallel to the radiographic results comparing TKA’s performed with manual and computer assisted instrumentation. In those studies, a reduction in outliers was consistently associated with the use of computer assisted techniques.

Customization makes it possible to fulfill design requirements during MIS-THA procedures, and has helped define the parameters of fit and fill. This study describes the results of using customization techniques to develop a femoral implant for utilization.

CT-based design criteria for femoral implants has-been developed and used for primary, cement-less, non-minimally invasive THA surgery. Over 1000 procedures performed with these devices have been associated with displaced femoral fractures, and have been revised for septic loosening. This study has 2 parts:

20 implants were designed and implanted with CT-based criteria that utilized the identical fit and fill standards of the custom implants previously established, but had short (< 115 mm), tapered stems;

The stem of these implants was shortened (95–115 mm) and tapered. Implants in both groups were inserted using a single incision, posterior-lateral MIS approach. Patients were followed clinically and radiographically for six months. Immediate full weightbearing and use of a single cane were encouraged.

The use of CT-based customization techniques is helpful for defining design criteria of femoral implants, but the instrumentation for inserting these implants must be adapted to the specific surgery. Customization also facilitates the design and evaluation of CAOS applications for inserting these MIS implants.

Introduction: Hospital accrediting organizations have recently emphasized the evaluation of and response to postoperative pain as the “fifth vital sign”. However, there are no prospective studies describing normal pain patterns after TKA to guide appropriate clinical responses. Similarly, there are no studies describing those at risk for unusual pain.

Purpose: To outline the pattern of normal recovery and identify factors predictive of significant pain after TKA.

Method: Prospective, observational, single surgeon design. Inclusion criteria: primary, cemented TKA for osteoarthritis. Clinical & radiographic measures obtained pre-op and at 1,3,6 and 12 months post-operatively. Predictive factors and post-operative outcomes included body mass index visual analogue scale (VAS), demographics, physical therapy, and component design, alignment and fixation. Psychometric testing included the Beck Depression Inventory and McGill Pain Questionnaire.

Results: 96 patients, 125 knees (mean age = 66, 55.2% women). Mean VAS at pre-op, 1,3, 6 and 12 month visits were 51.1(SD 23.8), 37.4(21.8), 27.0(22.2), 20.8(20.3), and 18.0(21.0), respectively. significant pain (VAS> 40) was reported by 61.51% of patients pre-op, 41.7% at 1 month, 24.0% 3 months, 16.7% 6 months, and 8.3% 12 months. There were no differences in pain based on the type of anesthesia, weight, age or gender. Preoperative elevated depression, anxiety and pain-related suffering descriptors predicted greater pain during the first 6 months after surgery, but did not ultimately affect recovery. Patients who had greater pain (VAS> 40) used more home and outpatient physical therapy (p=0.25).

Conclusion: Contrary to common beliefs, many patients (22%) still experience significant pain up to six months after TKA, despite absence of clinical or radiographic abnormalities. significant pain (VAS > 40mm) after six months may be indicative of an abnormal pain experience. Preoperative pain, depression and suffering are associated with increased early pain andutilization of therapy.

Significance: Since DRG-based Medicare payments to hospitals, length of stay (LOS) after Total Knee Arthroplasty (TKA) has declined dramatically. This reduction was accomplished in part by transferring patients to DRG-exempt rehabilitation units. Despite the regular use and expense of inpatient rehabilitation after TKA, there have been no prospective studies defining its efficacy. Purpose: Determine the impact of inpatient rehabilitation on TKA outcome.

Methods: Prospective, observational, single surgeon, single facility design.Inclusion criteria:primary,cemented TKA for OA between 1998–1999. All postoperative and rehabilitative care dictated by clinical protocol. Subjects were evaluated pre-op, at 1,3 and 6 months post-op. Patient (demographics, comorbidities), psychological (depression, anxiety), surgical (implant type, fixation, alignment), resource utilization (LOS, outpatient/home PT visits, rehabilitation LOS), complications, functional (knee flexion, gait, assistive device, Knee Society Score (KSS)) and pain (visual analogue scale, medication use) data obtained. Principle outcomes were pain, knee flexion, function, KSS, number of PT visits.

Results: 125 knees, 56 bilateral. No patient lost to follow-up. Mean age 66 years (36–85). At six months follow-up, postoperative KSS score was 164.4(94–200), flexion 114.3(80–130), VAS 18(SD 21). Patients discharged to rehabilitation had significantly lower preoperative KSS scores (89, SD30) than those discharged to home (104.6, SD24.4)p=035. There were no other differences between groups. Patients discharged directly to home had a greater knee flexion (p=005), walk farther (p=024), climb stairs easier (p=036), and utilized less home physical therapy (p=030) than patients discharged to rehabilitation.

Conclusion: This study was unable to demonstrate a benefit of inpatient rehabilitation after TKA. However, patients transferred to inpatient rehabilitation were less functional before surgery than those discharged home. Further studies are needed to determine if these patients benefit from inpatient rehabilitation versus home care.

Osteolysis secondary to polyethylene wear is the most serious aseptic long-term complication following THR. Studies have shown that fixation with screws, modularity and lack of extensive bone ingrowth are associated with increased osteolysis. This study examines the initial experience with a cup designed to address these issues.

One hundred and twenty-seven consecutive primary THR were performed between 1997–1999 using unce-mented monoblock, elliptical, tantalum cup without screw holes. Average follow-up 40 months (range 24 to 61). 79 THR in females, 48 in males. 48% THR hybrid fixed, 52% uncemented. Average age 61.6 years (range 19 to 88). Pre and post-operative clinical assessment with Harris hip score (hhs), WOMAC, SF-36. One independent, blinded observer performed zonal radiographic analysis with modified DeLee and Charnley method.

Average hhs at recent follow-up 93 (range 85 to 100). All shells appear fixed with bone ingrowth. Dome-gaps present in 6 cups post-op; all have filled in. Radiolucencies at follow-up: 4% zone 1, 8% zone 2; none greater than 1 mm. No cup migration. 8 cup related complications: 5 dislocations (4%) 1 subluxation, 2 undisplaced rim fractures (1.7% – no treatment). 3 dislocations, 1 subluxation occurred more than three months post-op. 3 revisions: 1 deep wound infection, 1 liner exchange (using reaming technique), 1 femoral head exchange.

Uncemented monoblock, elliptical tantalum cup without holes provides secure, symptom-free fixation at 4 years. No complications associated with use of tantalum. Elliptical shape associated with dome gaps, all of which appeared to fill by 3 months. Monoblock design results in increased polyethylene lip prominence associated with 6 cases of instability. Effect of prominent rim on impingement and long-term wear requires careful follow-up.

Pelvic osteolysis secondary to polyethylene wear is a major complication following THR. Identification of implant specific characteristics associated with osteolysis is essential. The purpose of this study is to compare incidence of CT scan identifiable osteolysis in 2 groups of young, active patients following THR; one with multi-holed acetabular shells with screws, one with cups without screw holes.

Between 1990–1993, 77 patients (85 hips) underwent THR with a cementless titanium, multi-holed shell with screws, modular, compression molded polyethylene and an uncemented titanium femoral stem. Average follow-up: 9 years, average age at surgery: 51 years. Between 1984–1987, 163 patients (183 hips) underwent THR with a cementless cobalt-chrome, solid shell, modular, heat-pressed polyeth-ylene liner and uncemented cobalt-chrome femoral stem. Average follow-up: 16 years, average age at operation: 52 years. All polyethylene was irradiated in air. At most recent follow-up, CT scans with metal suppression software was obtained to evaluate incidence of pelvic osteolysis. Patients classified: Group 1-no osteolysis, Group 2-cavitary osteolysis, Group 3-segmental osteolysis.

Patients with titanium, multi-holed shells had: Group 1-50.0%, Group 2-38.7%, and Group 3-11.3%. Patients with cobalt-chrome, solid shells had: Group 1-59.3%, Group 2-33.3% and Group 3-7.4%.

Although the patients with solid cups had much longer follow-up, less secure capture mechanism, less congruency between polyethylene and shell, and heat-pressed polyethylene, the incidence and extent of pelvic osteolysis was less than in the patients with multi-holed shell with screws. The presence of 6.5 mm cancellous screws is a serious independent risk factor for pelvic osteolysis following THR.