MAUDE Adverse Event Report: ZIMMER GMBH ALLOCLASSIC SL STEM, UNCEMENTED, 4, TAPER 12/14; ALLOCLASSIC ZWEYMUELLER SL/SLL FEMORAL STEM

Model Number N/A

Device Problem Retraction Problem (1536)

Patient Problems Failure of Implant (1924); Injury (2348)

Event Date 12/20/2011

Event Type  Injury  

Manufacturer Narrative

The manufacturer did not receive devices for review.X-ray pictures were received and will be reviewed within the investigation.Where lot numbers were received for the device, the device history records were reviewed and found to be conforming.A cause for this specific event cannot be ascertained from the information provided.As soon as additional information become available and/or an investigation result be available, an amended medical device report will be submitted.Zimmer¿s reference number of this file is (b)(4).

Event Description

It was reported that the patient was implanted an alloclassic sl stem, uncemented, 4, taper 12/14 on the right side on (b)(6) 2011 and was revised on (b)(6) 2011 due to luxation and sinking of the stem.Only the stem and the head were removed.

Manufacturer Narrative

Investigation results were made available.Additional: if follow-up, what type? update: model/lot #, date received by mfr, type of reports, if follow-up, what type?, evaluation codes, additional mfr narrative.Device history records (dhr): the device manufacturing quality records indicate that the released components met all requirements to perform as intended.Trend analysis: no trend identified.Review of event description: it was reported that the patient underwent a total hip replacement on (b)(6) 2011.It was reported that after seven days the alloclassic sl uncemented stem subsided approximately 10mm and that the patient was experiencing dislocation of the hip.The hip prosthesis was revised on (b)(6) 2011, but only the stem and the head were replaced.Review of received data: six x-rays were received for investigation.One x-ray is dated (b)(6) 2011 and shows the postoperative situation after the total hip replacement of the right hip.The x-ray has a poor image quality therefore comments regarding the bony situation cannot be made.On the x-ray it can be observed that the stem is protruding from the femoral resection plane.Three x-rays are dated (b)(6) 2011.Two x-rays have an acceptable image quality, while the third, which show a dislocated hip, has poor image quality.The first x-ray, taken approximately at 8:30 show the hip implant of the patient and compared to the postoperative x-ray the stem is seated more distal in the bone.This observation can be easily recognized by the changed position of the proximal end of the stem, which is first above and then approximately at the height of the femoral resection plane.The third radiograph taken at 11:16 shows the dislocated hip joint of the patient.No other conspicuousness can be observed as the x-ray image has poor quality.Two x-rays are dated (b)(6) 2011.The first x-ray has poor image contrast, but it can be recognized that the hip is dislocated.The second x-ray has a better image quality and shows the hip of the patient which has been reduced.The position of the stem can be compared with the ap x-ray dated (b)(6) 2011.Although the angle of the x-ray projection is slightly different, it seems that the stem further subsided.No changes in the position of the cup are observed.Two additional x-rays are available for investigation.According to the file name, the x-rays were taken on (b)(6) 2012, which is after the revision of the alloclassic stem and head.As the cup and the inlay have not been revised, the ap x-ray without date was used to measure the inclination angle which is approx.50°.A reliable analysis of the ante- or retroversion is not possible on planar x-rays.Therefore a template was overlaid on the cup profile shown on the x-ray to estimate this angle.With this method it is not possible to define if the profile comes from an ante- or retroversion since the profile of the cup is the same on the x-rays independent of the direction of rotation.In this case the ante- or retroversion is estimated to be approx.15°.The surgical report of the implantation performed on (b)(6) 2011 was received for review.The surgical report describes the implantation of a variall cup size 48, an alloclassic sl stem size 4, a ceramic inlay and a biolox ceramic head size 28 m with autologous cancellous bone grafting on the right hip due to pronounced cranio-lateral coxarthrosis.A lateral approach was chosen and the surgery was initiated.The surgical notes report that the removal of the femoral head was difficult due to the extremely taut patient's ligaments.By using additional instruments, the resected femoral head could be removed.The acetabulum was prepared and reamed until size 48.The bone was noted to have a good spherical shape and the size 48 cup could be fixed to the bone with the screws.The ceramic inlay was then placed in the cup and its fixation was tested.Afterward the leg was abducted and rotated and the preparation of the femur was started.The femur was rasped until size 4, where the sound of the cortical bone was heard.Trial reduction of the hip with a medium neck.Tight position and no tendency to luxation were noted.Therefore the definitive implants were implanted.Before doing this, some autologous cancellous bone taken from the resected femoral head was used to fill the gap between stem and cortical bone and the stem was impacted.After lavage of the joint, the joint was tested with no conspicuousness.Devices analysis: no product was returned to zimmer biomet for in-depth analysis.Review of product documentation: according to the surgical technique for alloclassic variall cup valid at the time of implantation and revision, a cerasul inlay can only be used in combination with a cerasul head.It is mentioned as follows: "important: a metasul gamma insert may only be combined with metasul heads and a cerasul gamma insert only with cerasul heads." therefore the product combination was not approved by zimmer biomet.The surgical technique for alloclassic zweymüller stem states for templating the femur: "select the femoral template size that will best fit the proximal and distal femur and equalize the leg length" and "the proximal tip of the prosthesis and the tip of the greater trochanter are suitable reference points for determining the height of the final implant." for stem implantation, it is further stated that: "the stem is inserted and impacted with the impactor in contact with the proximal tip of the prosthesis.As with the rasp, the tone of the hammer blow will change once cortical bone is engaged".According to the surgical technique for alloclassic variall cup: "correct alignment of the reamer is an important requirement for correctly positioning the implant.The reamer axis is ideally positioned at 35° to 45° of inclination and of 10° to 20° of anteversion.".Additionally it is stated that "placing the cup in a too vertical position must definitely be avoided, particularly when using ceramic inserts." root cause analysis: the surgical report mentions the grafting of the femur by autologous cancellous bone before implantation of the definitive stem and head.The postoperative x-ray suggests that the definitive stem was not completely impacted as intended as its proximal end is higher than the greater trochanter.Six days after implantation, on (b)(6) 2011, the stem subsided and the patient experienced dislocation of the hip.One day later, on (b)(6) 2011, the hip was reduced and from the review of the x-ray it seems that the stem has subsided further.The inclination angle of the cup was measured to be approx.50° and the ante- or retroversion is estimated to be approx.15°.According to surgical technique for alloclassic variall cup, the ideal cup position is 35° to 45° of inclination and of 10° to 20° of anteversion, and it is also stated that a too vertical position must definitely be avoided, particularly when using ceramic inserts.The same surgical technique also states that a cerasul inlay may only be used in combination with a cerasul head.Therefore, the product combination biolox head-cerasul inlay was not approved by zimmer biomet.The above observations could lead to the hypothesis that the stem was not fully impacted as intended.This then potentially caused the implant to subside, which could have contributed to mis-balance of the soft tissues and to hip dislocation.Additionally, the inclination angle of the cup was measured to be approx.50° which is more than the ideal cup inclination.However, it is unknown if and to which extent the mentioned factors contributed to the reported stem subsidence and hip dislocation.Conclusion summary: the investigation could lead to following hypothesis that the stem was not fully impacted as intended.This then potentially caused the implant to subside, which could have contributed to mis-balance of the soft tissues and to hip dislocation.Additionally, the inclination angle of the cup was measured to be approx.50° which is more than the ideal cup inclination.However, it is unknown if and to which extent the mentioned factors contributed to the reported stem subsidence and hip dislocation.Additionally, it has to be mentioned that the product combination was not approved by zimmer biomet.The need for corrective measures is not indicated and zimmer (b)(4) considers this case as closed.(b)(4).

• Brand Name: ALLOCLASSIC SL STEM, UNCEMENTED, 4, TAPER 12/14
• Type of Device: ALLOCLASSIC ZWEYMUELLER SL/SLL FEMORAL STEM
• Manufacturer (Section D): ZIMMER GMBH; sulzer allee 8; sulzer industrie park; winterthur 8404 ; SZ 8404
• Manufacturer (Section G): ZIMMER GMBH; sulzer allee 8; sulzer industrie park; winterthur 8404 ; SZ 8404
• Manufacturer Contact: kevin escapule ; 1800 west center street; warsaw, IN 46580 ; 8006136131
• MDR Report Key: 5824822
• MDR Text Key: 50509263
• Report Number: 0009613350-2016-01090
• Device Sequence Number: 1
• Product Code: LZO
• Combination Product (y/n): N
• Reporter Country Code: AU
• Number of Events Reported: 1
• Summary Report (Y/N): N
• Report Source: Manufacturer
• Source Type: foreign,health professional
• Reporter Occupation: Physician
• Type of Report: Initial,Followup
• Report Date: 07/03/2016

1 Device was Involved in the Event

1 Patient was Involved in the Event

• Date FDA Received: 07/27/2016
• Is this an Adverse Event Report?: Yes
• Is this a Product Problem Report?: No
• Device Operator: Lay User/Patient
• Device Expiration Date: 07/31/2015
• Device Model Number: N/A
• Device Catalogue Number: 2844
• Device Lot Number: 2591283
• Other Device ID Number: 00889024465572
• Was Device Available for Evaluation?: No
• Is the Reporter a Health Professional?: Yes
• Date Manufacturer Received: 11/02/2016
• Was Device Evaluated by Manufacturer?: Device Not Returned to Manufacturer
• Date Device Manufactured: 01/20/2011
• Is the Device Single Use?: Yes
• Is This a Reprocessed and Reused Single-Use Device?: No
• Type of Device Usage: Initial
• Removal/Correction Number: N/A
• Patient Sequence Number: 1
• Patient Outcome(s): Hospitalization; Required Intervention
• Patient Age: 71 YR
• Patient Weight: 115