Metal-backed versus all-polyethylene tibial components in primary total knee arthroplasty

Figures & data

Figure 1. Flow diagram of selection process.

Table 1. Characteristics of studies included

Study	Methods	Participants	Interventions	Outcomes
Adalberth et al. (2000) Sweden	Sealed envelope	MB: 20 knees; AP: 20 knees Similar DC Inclusion criteria: primary OA (Ahlbäck grades 3–4, >60 years old, body weight <100kg) Exclusion criteria: previous ipsilateral knee surgery; inpropriate marking of the implant and bone	Brand: AGC (Anatomic Graduated Component) Cement: yes Patella: resurfacing PCL: retention Arthrotomy: MPP Identical postoperative regime	Radiographic outcome KSS score ROM Complications Follow-up:24months
Gioe et al. (2000) USA	Method of randomization, allocation concealment or blinding not described	MB: 102knees; AP: 111 knees Similar DC Inclusion criteria: OA, IA, PTA (≥60 years old) Exclusion criteria: necessitating bone grafting, modular stems or more constrained designs	Brand: PFC (Depuy) PCL: retention Cement: yes Arthrotomy: MPP 4 senior surgeons Identical postoperative regime	Radiographic outcome KSS score ROM SF-36 Complications Survivorship Follow-up: 3–5 years
Adalberth et al. (2001) Sweden	Sealed envelope	MB: 18 knees; AP: 20 knees Similar DC Inclusion criteria: primary OA (Ahlbäck grades 3–4, >50 years old, body weight <100kg) Exclusion criteria: previous ipsilateral knee surgery; inpropriate marking of the implant and bone	Brand: Freeman-Samuelson (Sulzer Orthopedics) Cement: yes (AP) Patella: resurfacing PCL: sacrifice(if necessary) 2 experienced surgeons Identical postoperative regime	Radiographic outcome KSS score ROM Complications Follow-up: 24months
Norgren et al. (2004) Sweden	Sealed envelope	MB: 11knees; AP: 12 knees Similar DC Inclusion criteria: primary OA (Ahlbäck grades 3–4, >60 years old, body weight <120kg)	Brand: Profix (Smith & Nephew) Cement: yes (cement applied at the cut proximal tibia and partly around the stem) Single surgeon The same surgical technique Identical postoperative regime	Radiographic outcome KSS score ROM Complications Follow-up: 24months
Hyldahl et al. (2005a) Sweden	Stratified randomization	MB: 16 knees; AP: 20 knees Similar DC Inclusion criteria: primary OA (Ahlbäck grades 3–4, Exclusion criteria: previous Surgery; unvisualized markers	Brand: AGC (Anatomic Graduated Component) PCL: retention Cement: yes (proximal cementing leaving the stem uncemented) Patella: no resurfacing Arthrotomy: medial 2 experienced surgeons Identical postoperative regime	Radiographic outcome HSS score Complications Follow-up:24months
Hyldahl et al. (2005b) Sweden	Stratified randomization	MB: 20 knees; AP: 20 knees Similar DC Inclusion criteria: primary OA (Ahlbäck grades 3–4, Exclusion criteria: previous Surgery; unvisualized markers	Brand: AGC (Anatomic Graduated Component) PCL: retention Cement: yes (proximal cementing with cement around the stem) Patella: no resurfacing Arthrotomy: medial 2 experienced surgeons Identical postoperative regime	Radiographic outcome HSS score Complications Follow-up: 24months
Muller et al. (2006) UK	Block randomization Sealed envelope	MB: 19 knees; AP: 21 knees Similar DC Inclusion criteria: OA, RA (>65 years old) Exclusion criteria: previous knee surgery; renal transplant; Paget's disease; metabolic bone disease, joint sepsis; steroid use; psychosocial or physical disability; bone deficiencies	Brand: PFC-Σ (Depuy) Arthrotomy: MPP 4 consultant surgeons Identical postoperative regime	Radiographic outcome OKS score SF-12 Follow-up: 24months
Gioe et al. (2007) USA	Method of randomization, allocation concealment or blinding not described	MB: 70knees; AP: 97 knees Similar DC Inclusion criteria: OA, IA, PTA (≥60 years old) Exclusion criteria: necessitating bone grafting, modular stems or more constrained designs	Brand: PFC (Depuy) PCL: retention Cement: yes Arthrotomy: MPP 4 senior surgeons Identical postoperative regime	Radiographic outcome KSS score ROM SF-36 Complications Survivorship Follow-up: 10 years
Bettinson et al. (2009) UK	Computer-generated random codes and stratified randomization Sealed envelope	MB: 304 knees; AP: 262 knees Similar DC Inclusion criteria: primary OA, RA (≥55 years old) Exclusion criteria: infection; unstable knee requiring constrained or semi-constrained prosthesis	Brand: Kinemax Plus (Stryker) PCL: retention Cement: yes Patella: no resurfacing The same surgical technique Identical postoperative regime	Complications Survivorship Follow-up: 10 years
The KAT Trial Group (2009) UK	Automated centralized telephone randomization and stratified randomization	MB: 202 knees; AP: 207 knees Similar DC Inclusion criteria: primary OA, RA	116 surgeons follow their standard practice	OKS score, SF-12 EQ-5D Complications Follow-up: 24months

AP: all-polyethylene; MB: metal-backed; DC: demographic characteristic; OA: osteoarthritis; RA: rheumatoid arthritis; PTA: posttraumatic arthritis; IA: inflammatory arthritis; PCL: posterior cruciate ligament; MPP: medial parapatellar; ROM: range of motion; KSS: Knee Society score; OKS: Oxford Knee score; HSS: Hospital for Special Surgery; SF: Short Form; EQ-SD: EuroQol SD.

Figure 2. Funnel plot for these studies reporting postoperative complications after total knee arthroplasty.

Figure 3. Forest plot assessing postoperative complications after total knee arthroplasty.

Table 2. Summary of postoperative complications reported in the trials included in this analysis

Complications	MB	AP
Local complications
Infection	10	14
Knee pain	0	2
Stiffness	2	3
Patellofemoral problem	2	3
(patellar fracture, patellar maltracking, anterior knee pain)
Femoral neck fracture or fall	2	0
Instability	1	1
Skin complication	2	2
Surgical complications	3	0
Subtotal	22	25
Systemic complications
DVT or pulmonary embolism	4	8
Thrombolytic complications	2	3
Myocardial infarction	1	1
Urinary complications	2	3
Medical complications	16	14
Subtotal	25	28
Grand total	47	54

DVT: deep vein thrombosis.

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