Clinical Study Comparing Two Implant Surface Finishes in Patients Undergoing Cementless Total Hip Replacement - Study Results

Study Type:	Interventional
Study Design:	Allocation: Randomized; Endpoint Classification: Safety/Efficacy Study; Intervention Model: Parallel Assignment; Masking: Open Label; Primary Purpose: Treatment
Conditions:	Osteoarthritis Rheumatoid Arthritis Post-traumatic Arthritis Avascular Necrosis Acute Fracture
Interventions:	Device: non-coated femoral hip stem Device: coated femoral hip stem

Participant Flow

Recruitment Details

Key information relevant to the recruitment process for the overall study, such as dates of the recruitment period and locations
Recruitment began in September 2002 and ended June 2006. Study subjects were recruited and enrolled in medical clinics by orthopaedic surgeons at eight investigational sites. Each site could enroll a maximum of 50 subjects. Recruitment was based on the inclusion and exclusion criteria as indicated in the study protocol.

Pre-Assignment Details

Significant events and approaches for the overall study following participant enrollment, but prior to group assignment
Immediately before surgery, the implant type was determined according to the randomization schedule. Enrolled subjects may have been excluded from the trial before assignment to the study arm based upon results of pre-operative clinical evaluations and radiographs that would exclude a subject based on exclusion criteria in the study protocol.

Reporting Groups

Description

DuoFix HA

The Summit™ DuoFix™ HA stems are primary, cementless hip implants. Summit™ cementless stems feature 3°-tapered body geometry to enhance fit, and are manufactured from forged titanium alloy. The Summit™ cementless stems are designed to load the femur toward the upper part of the stem, and therefore the Porocoat® porous coating is applied only to the upper body of the stem. The DuoFix™ HA stem also has a thin coating of hydroxyapatite on this porous-coated surface. This HA coating is only 35 microns thick, so the optimum pore size is maintained. The lower portion of the stem has a grit-blasted surface, which promotes bone on-growth and the polished bullet-tip prevents end-stem loading.

Porocoat Porous Coated

The Summit™ Porocoat® stems are primary, cementless hip implants that a feature 3°-tapered body geometry to enhance fit, and are manufactured from forged titanium alloy. The Summit™ cementless stems are designed to load the femur toward the upper part of the stem, and therefore the Porocoat® porous coating is applied only to the upper body of the stem. The lower portion of the stems has a grit-blasted surface, which promotes bone on-growth and the polished bullet-tip prevents end-stem loading.

Participant Flow: Overall Study

	DuoFix HA	Porocoat Porous Coated
STARTED	121 ^[1]	124 ^[1]
Postoperative to 6 Month Follow up	93	100
12 Month Follow	86	94
24 Month Follow up	60	71
36 Month Follow up	56	42
48 Month Follow up	29	22
60 Month Follow up	13	15
COMPLETED	13	15
NOT COMPLETED	108	109

[1]	400 subjects were to be followed for 5 years; due to slow enrollment study closed early with 245.

Baseline Characteristics

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Reporting Groups

	Description
DuoFix HA	The Summit™ DuoFix™ HA stems are primary, cementless hip implants. Summit™ cementless stems feature 3°-tapered body geometry to enhance fit, and are manufactured from forged titanium alloy. The Summit™ cementless stems are designed to load the femur toward the upper part of the stem, and therefore the Porocoat® porous coating is applied only to the upper body of the stem. The DuoFix™ HA stem also has a thin coating of hydroxyapatite on this porous-coated surface. This HA coating is only 35 microns thick, so the optimum pore size is maintained. The lower portion of the stem has a grit-blasted surface, which promotes bone on-growth and the polished bullet-tip prevents end-stem loading.
Porocoat Porous Coated	The Summit™ Porocoat® stems are primary, cementless hip implants that a feature 3°-tapered body geometry to enhance fit, and are manufactured from forged titanium alloy. The Summit™ cementless stems are designed to load the femur toward the upper part of the stem, and therefore the Porocoat® porous coating is applied only to the upper body of the stem. The lower portion of the stems has a grit-blasted surface, which promotes bone on-growth and the polished bullet-tip prevents end-stem loading.
Total	Total of all reporting groups

Baseline Measures

	DuoFix HA	Porocoat Porous Coated	Total
Number of Participants [units: participants]	121	124	245
Age [units: years] Mean ± Standard Deviation	64.5 ± 8.2	63.2 ± 9.2	63.8 ± 8.7
Gender [units: participants]
Female	67	64	131
Male	54	60	114
Region of Enrollment [units: participants]
United States	121	124	245

Outcome Measures

1. Primary:

Harris Hip Score (HHS) [ Time Frame: Preoperative, 6, 12, 24, 36, 48, and 60 months ]

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Measure Type	Primary
Measure Title	Harris Hip Score (HHS)
Measure Description	The Harris Hip scoring system assigns a numeric value to responses from patients and assessments made by a surgeon. A score of 90-100 is excellent, 80-90 is good, 70-80 is fair, 60-69 is poor, and 60 or below is failed. The patient records the following: pain level, need for assistance when walking, presence of a limp, distance able to walk, ability to put on shoes and socks, climb stairs, use public transportation and the length of time one is able to comforatably sit in a chair are all scored. The doctor assesses patient hip function by testing flexion, extension, adduction and abduction.
Time Frame	Preoperative, 6, 12, 24, 36, 48, and 60 months
Safety Issue	No

Population Description

Explanation of how the number of participants for analysis was determined. Includes whether analysis was per protocol, intention to treat, or another method. Also provides relevant details such as imputation technique, as appropriate.
Before the first interval there were five missing HHS scores for the DuoFix arm and four missing HHS scores for the Porocoat Porous Coated arm. At the final interval (60 months), there were eleven subjects in the DuoFix arm with complete HHS scores and there were fourteen subjects in the Porocoat Porous Coated arm with complete HHS scores.

Reporting Groups

Description

DuoFix HA

The Summit™ DuoFix™ HA stems are primary, cementless hip implants. Summit™ cementless stems feature 3°-tapered body geometry to enhance fit, and are manufactured from forged titanium alloy. The Summit™ cementless stems are designed to load the femur toward the upper part of the stem, and therefore the Porocoat® porous coating is applied only to the upper body of the stem. The DuoFix™ HA stem also has a thin coating of hydroxyapatite on this porous-coated surface. This HA coating is only 35 microns thick, so the optimum pore size is maintained. The lower portion of the stem has a grit-blasted surface, which promotes bone on-growth and the polished bullet-tip prevents end-stem loading.

Porocoat Porous Coated

The Summit™ Porocoat® stems are primary, cementless hip implants that a feature 3°-tapered body geometry to enhance fit, and are manufactured from forged titanium alloy. The Summit™ cementless stems are designed to load the femur toward the upper part of the stem, and therefore the Porocoat® porous coating is applied only to the upper body of the stem. The lower portion of the stems has a grit-blasted surface, which promotes bone on-growth and the polished bullet-tip prevents end-stem loading.

Measured Values

	DuoFix HA	Porocoat Porous Coated
Number of Participants Analyzed [units: participants]	121	124
Harris Hip Score (HHS) [units: Units on a scale] Mean ± Standard Deviation
Preoperative HHS	49.9 ± 13.4	51.2 ± 14.0
Postoperative to 6 Month HHS	90.2 ± 10.3	91.6 ± 8.3
12 Month HHS	92.8 ± 7.9	92.3 ± 11.6
24 Month HHS	93.3 ± 7.8	93.5 ± 9.7
36 Month HHS	94.0 ± 8.5	93.8 ± 9.4
48 Month HHS	91.8 ± 12.2	95.5 ± 10.5
60 Month HHS	93.8 ± 7.9	93.6 ± 7.8

No statistical analysis provided for Harris Hip Score (HHS)

2. Secondary:

Medical Imaging [ Time Frame: postoperative, 6, 12, 24, 36, 48 and 60 months ]

Results not yet posted. Anticipated Posting Date: No text entered. Safety Issue: Yes

Serious Adverse Events

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Other Adverse Events

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More Information

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Certain Agreements:

Principal Investigators are NOT employed by the organization sponsoring the study.

There IS an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.

The agreement is:

	The only disclosure restriction on the PI is that the sponsor can review results communications prior to public release and can embargo communications regarding trial results for a period that is less than or equal to 60 days. The sponsor cannot require changes to the communication and cannot extend the embargo.
	The only disclosure restriction on the PI is that the sponsor can review results communications prior to public release and can embargo communications regarding trial results for a period that is more than 60 days but less than or equal to 180 days. The sponsor cannot require changes to the communication and cannot extend the embargo.
	Other disclosure agreement that restricts the right of the PI to discuss or publish trial results after the trial is completed.

Limitations and Caveats

Limitations of the study, such as early termination leading to small numbers of participants analyzed and technical problems with measurement leading to unreliable or uninterpretable data
The protocol called for 400 subjects to be followed for 5 years, but due to slow enrollment the study closed early. 245 subjects were enrolled & study endpoint was modified to 2 years. Enrollment closed on June 30, 2006; study closed on Jan 29, 2009.

Results Point of Contact:

Name/Title: Barry Sisson
Organization: DePuy Orthopaedics, Inc
phone: 574-372-7156
e-mail: BSisson@its.jnj.com

No publications provided

Responsible Party:	DePuy Orthopaedics
ClinicalTrials.gov Identifier:	NCT00306917 History of Changes
Other Study ID Numbers:	SPD
Study First Received:	March 23, 2006
Results First Received:	January 29, 2010
Last Updated:	December 1, 2011
Health Authority:	United States: Food and Drug Administration